diff options
author | Karl Berry <karl@freefriends.org> | 2021-09-21 16:46:46 +0000 |
---|---|---|
committer | Karl Berry <karl@freefriends.org> | 2021-09-21 16:46:46 +0000 |
commit | 307dd6b08adb9d64007e887bd99927bf55567f13 (patch) | |
tree | 7dceeefebd8ee7b2f593235e4454500194640763 /Build/source/texk | |
parent | 659b02c307c05da212ec98a3069ed1c4d39ab58d (diff) |
hitexdir: initial import, omitted from build by default
git-svn-id: svn://tug.org/texlive/trunk@60569 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/texk')
-rwxr-xr-x | Build/source/texk/configure | 17 | ||||
-rw-r--r-- | Build/source/texk/web2c/ChangeLog | 6 | ||||
-rw-r--r-- | Build/source/texk/web2c/Makefile.am | 6 | ||||
-rw-r--r-- | Build/source/texk/web2c/Makefile.in | 809 | ||||
-rw-r--r-- | Build/source/texk/web2c/ac/web2c.ac | 3 | ||||
-rw-r--r-- | Build/source/texk/web2c/c-auto.in | 2 | ||||
-rwxr-xr-x | Build/source/texk/web2c/configure | 30 | ||||
-rw-r--r-- | Build/source/texk/web2c/configure.ac | 2 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/am/hitex.am | 100 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/format.w | 10509 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/hitex.w | 4753 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/htex.w | 29180 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/lex.sed | 5 | ||||
-rw-r--r-- | Build/source/texk/web2c/hitexdir/yacc.sed | 3 |
14 files changed, 45184 insertions, 241 deletions
diff --git a/Build/source/texk/configure b/Build/source/texk/configure index d0a121e16f6..81475012866 100755 --- a/Build/source/texk/configure +++ b/Build/source/texk/configure @@ -765,6 +765,7 @@ enable_uptex_synctex enable_euptex enable_euptex_synctex enable_aleph +enable_hitex enable_pdftex enable_pdftex_synctex enable_luatex @@ -1560,6 +1561,7 @@ Optional Features: --disable-euptex do not compile and install e-upTeX --disable-euptex-synctex build e-upTeX without SyncTeX support --disable-aleph do not compile and install Aleph + --enable-hitex compile and install HiTeX --disable-pdftex do not compile and install pdfTeX --disable-pdftex-synctex build pdfTeX without SyncTeX support --disable-luatex do not compile and install LuaTeX @@ -4560,6 +4562,21 @@ case $enable_aleph in #( *) : enable_aleph=yes ;; esac +# Check whether --enable-hitex was given. +if test ${enable_hitex+y} +then : + enableval=$enable_hitex; +fi +case $enable_hitex in #( + yes | no) : + ;; #( + *) : + enable_hitex=no ;; +esac + +test "x$enable_web2c:$enable_hitex" = xyes:yes && { + need_zlib=yes +} # Check whether --enable-pdftex was given. if test ${enable_pdftex+y} then : diff --git a/Build/source/texk/web2c/ChangeLog b/Build/source/texk/web2c/ChangeLog index 480f59239f6..ef1f540253c 100644 --- a/Build/source/texk/web2c/ChangeLog +++ b/Build/source/texk/web2c/ChangeLog @@ -1,3 +1,9 @@ +2021-09-21 Karl Berry <karl@freefriends.org> + + * ac/web2c.ac (kpse_tex_progs): include hitex, disabled by default. + * Makefile.am: include hitexdir/am/hitex.am. + * hitexdir: new directory. + 2021-09-16 Andreas Scherer <https://ascherer.github.io> * Makefile.in, diff --git a/Build/source/texk/web2c/Makefile.am b/Build/source/texk/web2c/Makefile.am index 0ad8e4db3ab..1d8f29f4d63 100644 --- a/Build/source/texk/web2c/Makefile.am +++ b/Build/source/texk/web2c/Makefile.am @@ -274,6 +274,9 @@ include $(srcdir)/uptexdir/am/uptex.am ## e-upTeX include $(srcdir)/euptexdir/am/euptex.am +## hiTeX +include $(srcdir)/hitexdir/am/hitex.am + ## pdfTeX include $(srcdir)/pdftexdir/am/libpdftex.am include $(srcdir)/pdftexdir/am/pdftex.am @@ -289,12 +292,9 @@ include $(srcdir)/luatexdir/am/libluatex.am include $(srcdir)/luatexdir/am/luaffi.am include $(srcdir)/luatexdir/am/luatex.am - ## luahbTeX include $(srcdir)/luatexdir/am/luaharfbuzz.am - - ## XeTeX include $(srcdir)/xetexdir/am/xetex.am diff --git a/Build/source/texk/web2c/Makefile.in b/Build/source/texk/web2c/Makefile.in index eab99a2e180..7273a62c1ed 100644 --- a/Build/source/texk/web2c/Makefile.in +++ b/Build/source/texk/web2c/Makefile.in @@ -112,7 +112,8 @@ EXTRA_PROGRAMS = $(am__EXEEXT_1) tex$(EXEEXT) mf$(EXEEXT) \ mfluajit$(EXEEXT) mfluajit-nowin$(EXEEXT) mpost$(EXEEXT) \ pmpost$(EXEEXT) upmpost$(EXEEXT) etex$(EXEEXT) ptex$(EXEEXT) \ $(am__EXEEXT_2) eptex$(EXEEXT) uptex$(EXEEXT) $(am__EXEEXT_3) \ - euptex$(EXEEXT) pdftex$(EXEEXT) ttf2afm$(EXEEXT) \ + euptex$(EXEEXT) hitex$(EXEEXT) hishrink$(EXEEXT) \ + histretch$(EXEEXT) pdftex$(EXEEXT) ttf2afm$(EXEEXT) \ pdftosrc$(EXEEXT) luatex$(EXEEXT) luajittex$(EXEEXT) \ luahbtex$(EXEEXT) luajithbtex$(EXEEXT) xetex$(EXEEXT) \ $(am__EXEEXT_4) aleph$(EXEEXT) synctex$(EXEEXT) \ @@ -128,22 +129,23 @@ bin_PROGRAMS = tangle$(EXEEXT) ctangle$(EXEEXT) $(am__EXEEXT_5) \ $(am__EXEEXT_21) $(am__EXEEXT_22) $(am__EXEEXT_23) \ $(am__EXEEXT_24) $(am__EXEEXT_25) $(am__EXEEXT_26) \ $(am__EXEEXT_27) $(am__EXEEXT_28) $(am__EXEEXT_29) \ - $(am__EXEEXT_30) $(am__EXEEXT_31) $(am__EXEEXT_32) + $(am__EXEEXT_30) $(am__EXEEXT_31) $(am__EXEEXT_32) \ + $(am__EXEEXT_33) noinst_PROGRAMS = tangleboot$(EXEEXT) ctangleboot$(EXEEXT) \ - $(am__EXEEXT_33) $(am__EXEEXT_34) $(am__EXEEXT_35) \ - $(am__EXEEXT_36) $(am__EXEEXT_37) $(am__EXEEXT_38) \ - $(am__EXEEXT_39) $(am__EXEEXT_40) $(am__EXEEXT_41) \ - $(am__EXEEXT_42) -TESTS = tangle.test $(am__EXEEXT_45) ctiedir/ctie.test \ + $(am__EXEEXT_34) $(am__EXEEXT_35) $(am__EXEEXT_36) \ + $(am__EXEEXT_37) $(am__EXEEXT_38) $(am__EXEEXT_39) \ + $(am__EXEEXT_40) $(am__EXEEXT_41) $(am__EXEEXT_42) \ + $(am__EXEEXT_43) +TESTS = tangle.test $(am__EXEEXT_46) ctiedir/ctie.test \ cwebdir/cweave.test tiedir/tie.test $(am__append_6) \ $(am__append_16) $(am__append_25) $(am__append_34) \ $(am__append_42) $(am__append_55) $(am__append_56) \ $(am__append_58) $(am__append_63) $(am__append_66) \ $(am__append_68) $(am__append_73) $(am__append_76) \ - $(am__append_78) $(am__append_83) $(am__append_104) \ - $(am__append_105) $(am__append_106) $(am__append_107) \ - $(am__append_115) $(am__append_117) $(am__append_119) \ - $(am__append_153) libmd5/md5.test + $(am__append_78) $(am__append_84) $(am__append_105) \ + $(am__append_106) $(am__append_107) $(am__append_108) \ + $(am__append_116) $(am__append_118) $(am__append_120) \ + $(am__append_154) libmd5/md5.test @WEB_TRUE@am__append_1 = $(web_programs) @WEB_TRUE@am__append_2 = $(web_tests) @TEX_TRUE@am__append_3 = tex @@ -228,150 +230,151 @@ TESTS = tangle.test $(am__EXEEXT_45) ctiedir/ctie.test \ @EUPTEX_TRUE@am__append_78 = $(euptex_tests) @EUPTEX_TRUE@am__append_79 = euptrip.diffs @EUPTEX_TRUE@am__append_80 = euptrip-clean -@MINGW32_TRUE@am__append_81 = \ +@HITEX_TRUE@am__append_81 = hitex hishrink histretch +@MINGW32_TRUE@am__append_82 = \ @MINGW32_TRUE@ pdftexdir/regex/regex.c \ @MINGW32_TRUE@ pdftexdir/regex/regex.h -@PDFTEX_TRUE@am__append_82 = pdftex ttf2afm pdftosrc -@PDFTEX_TRUE@am__append_83 = $(pdftex_tests) $(ttf2afm_tests) \ +@PDFTEX_TRUE@am__append_83 = pdftex ttf2afm pdftosrc +@PDFTEX_TRUE@am__append_84 = $(pdftex_tests) $(ttf2afm_tests) \ @PDFTEX_TRUE@ $(pdftosrc_tests) -@LUATEX_TRUE@am__append_84 = luatex -@LUATEX_TRUE@@WIN32_TRUE@am__append_85 = call_luatex -@LUATEX_TRUE@@WIN32_TRUE@am__append_86 = install-luatex-links -@LUATEX_TRUE@@WIN32_TRUE@am__append_87 = uninstall-luatex-links -@LUATEX_TRUE@@WIN32_FALSE@am__append_88 = luatex$(EXEEXT):texlua luatex$(EXEEXT):texluac -@LUAHBTEX_TRUE@am__append_89 = luahbtex -@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_90 = call_luahbtex -@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_91 = install-luahbtex-links -@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_92 = uninstall-luahbtex-links +@LUATEX_TRUE@am__append_85 = luatex +@LUATEX_TRUE@@WIN32_TRUE@am__append_86 = call_luatex +@LUATEX_TRUE@@WIN32_TRUE@am__append_87 = install-luatex-links +@LUATEX_TRUE@@WIN32_TRUE@am__append_88 = uninstall-luatex-links +@LUATEX_TRUE@@WIN32_FALSE@am__append_89 = luatex$(EXEEXT):texlua luatex$(EXEEXT):texluac +@LUAHBTEX_TRUE@am__append_90 = luahbtex +@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_91 = call_luahbtex +@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_92 = install-luahbtex-links +@LUAHBTEX_TRUE@@WIN32_TRUE@am__append_93 = uninstall-luahbtex-links # keep texlua[c] as links to luatex unless luatex is not installed. -@LUAHBTEX_TRUE@@LUATEX_FALSE@@WIN32_FALSE@am__append_93 = luahbtex$(EXEEXT):texlua luahbtex$(EXEEXT):texluac -@LUAJITTEX_TRUE@am__append_94 = luajittex -@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_95 = call_luajittex -@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_96 = install-luajittex-links -@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_97 = uninstall-luajittex-links -@LUAJITTEX_TRUE@@WIN32_FALSE@am__append_98 = luajittex$(EXEEXT):texluajit luajittex$(EXEEXT):texluajitc -@LUAJITHBTEX_TRUE@am__append_99 = luajithbtex -@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_100 = call_luajithbtex -@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_101 = install-luajithbtex-links -@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_102 = uninstall-luajithbtex-links +@LUAHBTEX_TRUE@@LUATEX_FALSE@@WIN32_FALSE@am__append_94 = luahbtex$(EXEEXT):texlua luahbtex$(EXEEXT):texluac +@LUAJITTEX_TRUE@am__append_95 = luajittex +@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_96 = call_luajittex +@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_97 = install-luajittex-links +@LUAJITTEX_TRUE@@WIN32_TRUE@am__append_98 = uninstall-luajittex-links +@LUAJITTEX_TRUE@@WIN32_FALSE@am__append_99 = luajittex$(EXEEXT):texluajit luajittex$(EXEEXT):texluajitc +@LUAJITHBTEX_TRUE@am__append_100 = luajithbtex +@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_101 = call_luajithbtex +@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_102 = install-luajithbtex-links +@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__append_103 = uninstall-luajithbtex-links # keep texluajit[c] as links to luajittex unless luajittex is not installed. -@LUAJITHBTEX_TRUE@@LUAJITTEX_FALSE@@WIN32_FALSE@am__append_103 = luajithbtex$(EXEEXT):texluajit luajithbtex$(EXEEXT):texluajitc -@LUATEX_TRUE@am__append_104 = $(luatex_tests) -@LUAHBTEX_TRUE@am__append_105 = $(luahbtex_tests) -@LUAJITTEX_TRUE@am__append_106 = $(luajittex_tests) -@LUAJITHBTEX_TRUE@am__append_107 = $(luajithbtex_tests) -@XETEX_TRUE@am__append_108 = xetex -@XETEX_MACOSX_TRUE@am__append_109 = -DXETEX_MAC -@XETEX_MACOSX_TRUE@am__append_110 = -std=c++11 -@XETEX_MACOSX_FALSE@am__append_111 = $(FONTCONFIG_INCLUDES) -@XETEX_MACOSX_FALSE@am__append_112 = $(FONTCONFIG_LIBS) -@XETEX_MACOSX_TRUE@am__append_113 = \ +@LUAJITHBTEX_TRUE@@LUAJITTEX_FALSE@@WIN32_FALSE@am__append_104 = luajithbtex$(EXEEXT):texluajit luajithbtex$(EXEEXT):texluajitc +@LUATEX_TRUE@am__append_105 = $(luatex_tests) +@LUAHBTEX_TRUE@am__append_106 = $(luahbtex_tests) +@LUAJITTEX_TRUE@am__append_107 = $(luajittex_tests) +@LUAJITHBTEX_TRUE@am__append_108 = $(luajithbtex_tests) +@XETEX_TRUE@am__append_109 = xetex +@XETEX_MACOSX_TRUE@am__append_110 = -DXETEX_MAC +@XETEX_MACOSX_TRUE@am__append_111 = -std=c++11 +@XETEX_MACOSX_FALSE@am__append_112 = $(FONTCONFIG_INCLUDES) +@XETEX_MACOSX_FALSE@am__append_113 = $(FONTCONFIG_LIBS) +@XETEX_MACOSX_TRUE@am__append_114 = \ @XETEX_MACOSX_TRUE@ xetexdir/XeTeXFontInst_Mac.cpp \ @XETEX_MACOSX_TRUE@ xetexdir/XeTeXFontInst_Mac.h \ @XETEX_MACOSX_TRUE@ xetexdir/XeTeXFontMgr_Mac.mm \ @XETEX_MACOSX_TRUE@ xetexdir/XeTeXFontMgr_Mac.h \ @XETEX_MACOSX_TRUE@ xetexdir/XeTeX_mac.c -@XETEX_MACOSX_FALSE@am__append_114 = \ +@XETEX_MACOSX_FALSE@am__append_115 = \ @XETEX_MACOSX_FALSE@ xetexdir/XeTeXFontMgr_FC.cpp \ @XETEX_MACOSX_FALSE@ xetexdir/XeTeXFontMgr_FC.h -@XETEX_TRUE@am__append_115 = $(xetex_tests) -@OTANGLE_TRUE@am__append_116 = $(omegaware_programs) -@OTANGLE_TRUE@am__append_117 = $(OTANGLE_tests) $(OMFONTS_tests) -@ALEPH_TRUE@am__append_118 = aleph -@ALEPH_TRUE@am__append_119 = $(aleph_tests) -@SYNCTEX_TRUE@am__append_120 = synctex -@SYNCTEX_TRUE@am__append_121 = $(LTLIBSYNCTEX) -@SYNCTEX_TRUE@am__append_122 = $(LIBSYNCTEX) -@MINGW32_TRUE@am__append_123 = -lshlwapi +@XETEX_TRUE@am__append_116 = $(xetex_tests) +@OTANGLE_TRUE@am__append_117 = $(omegaware_programs) +@OTANGLE_TRUE@am__append_118 = $(OTANGLE_tests) $(OMFONTS_tests) +@ALEPH_TRUE@am__append_119 = aleph +@ALEPH_TRUE@am__append_120 = $(aleph_tests) +@SYNCTEX_TRUE@am__append_121 = synctex +@SYNCTEX_TRUE@am__append_122 = $(LTLIBSYNCTEX) +@SYNCTEX_TRUE@am__append_123 = $(LIBSYNCTEX) @MINGW32_TRUE@am__append_124 = -lshlwapi -@TEX_SYNCTEX_TRUE@am__append_125 = -I$(srcdir)/synctexdir \ +@MINGW32_TRUE@am__append_125 = -lshlwapi +@TEX_SYNCTEX_TRUE@am__append_126 = -I$(srcdir)/synctexdir \ @TEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @TEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-tex.h\" -@TEX_SYNCTEX_TRUE@am__append_126 = $(ZLIB_LIBS) -@TEX_SYNCTEX_TRUE@am__append_127 = $(ZLIB_DEPEND) -@TEX_SYNCTEX_TRUE@am__append_128 = \ +@TEX_SYNCTEX_TRUE@am__append_127 = $(ZLIB_LIBS) +@TEX_SYNCTEX_TRUE@am__append_128 = $(ZLIB_DEPEND) +@TEX_SYNCTEX_TRUE@am__append_129 = \ @TEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @TEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @TEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @TEX_SYNCTEX_TRUE@ synctexdir/synctex-tex.h -@ETEX_SYNCTEX_TRUE@am__append_129 = -I$(srcdir)/synctexdir \ +@ETEX_SYNCTEX_TRUE@am__append_130 = -I$(srcdir)/synctexdir \ @ETEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @ETEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-etex.h\" -@ETEX_SYNCTEX_TRUE@am__append_130 = $(ZLIB_LIBS) -@ETEX_SYNCTEX_TRUE@am__append_131 = $(ZLIB_DEPEND) -@ETEX_SYNCTEX_TRUE@am__append_132 = \ +@ETEX_SYNCTEX_TRUE@am__append_131 = $(ZLIB_LIBS) +@ETEX_SYNCTEX_TRUE@am__append_132 = $(ZLIB_DEPEND) +@ETEX_SYNCTEX_TRUE@am__append_133 = \ @ETEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @ETEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @ETEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @ETEX_SYNCTEX_TRUE@ synctexdir/synctex-etex.h -@PTEX_SYNCTEX_TRUE@am__append_133 = -I$(srcdir)/synctexdir \ +@PTEX_SYNCTEX_TRUE@am__append_134 = -I$(srcdir)/synctexdir \ @PTEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @PTEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-ptex.h\" -@PTEX_SYNCTEX_TRUE@am__append_134 = $(ZLIB_LIBS) -@PTEX_SYNCTEX_TRUE@am__append_135 = $(ZLIB_DEPEND) -@PTEX_SYNCTEX_TRUE@am__append_136 = \ +@PTEX_SYNCTEX_TRUE@am__append_135 = $(ZLIB_LIBS) +@PTEX_SYNCTEX_TRUE@am__append_136 = $(ZLIB_DEPEND) +@PTEX_SYNCTEX_TRUE@am__append_137 = \ @PTEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @PTEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @PTEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @PTEX_SYNCTEX_TRUE@ synctexdir/synctex-ptex.h -@UPTEX_SYNCTEX_TRUE@am__append_137 = -I$(srcdir)/synctexdir \ +@UPTEX_SYNCTEX_TRUE@am__append_138 = -I$(srcdir)/synctexdir \ @UPTEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @UPTEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-uptex.h\" -@UPTEX_SYNCTEX_TRUE@am__append_138 = $(ZLIB_LIBS) -@UPTEX_SYNCTEX_TRUE@am__append_139 = $(ZLIB_DEPEND) -@UPTEX_SYNCTEX_TRUE@am__append_140 = \ +@UPTEX_SYNCTEX_TRUE@am__append_139 = $(ZLIB_LIBS) +@UPTEX_SYNCTEX_TRUE@am__append_140 = $(ZLIB_DEPEND) +@UPTEX_SYNCTEX_TRUE@am__append_141 = \ @UPTEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @UPTEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @UPTEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @UPTEX_SYNCTEX_TRUE@ synctexdir/synctex-uptex.h -@EPTEX_SYNCTEX_TRUE@am__append_141 = -I$(srcdir)/synctexdir \ +@EPTEX_SYNCTEX_TRUE@am__append_142 = -I$(srcdir)/synctexdir \ @EPTEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @EPTEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-eptex.h\" -@EPTEX_SYNCTEX_TRUE@am__append_142 = $(ZLIB_LIBS) -@EPTEX_SYNCTEX_TRUE@am__append_143 = $(ZLIB_DEPEND) -@EPTEX_SYNCTEX_TRUE@am__append_144 = \ +@EPTEX_SYNCTEX_TRUE@am__append_143 = $(ZLIB_LIBS) +@EPTEX_SYNCTEX_TRUE@am__append_144 = $(ZLIB_DEPEND) +@EPTEX_SYNCTEX_TRUE@am__append_145 = \ @EPTEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @EPTEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @EPTEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @EPTEX_SYNCTEX_TRUE@ synctexdir/synctex-eptex.h -@EUPTEX_SYNCTEX_TRUE@am__append_145 = -I$(srcdir)/synctexdir \ +@EUPTEX_SYNCTEX_TRUE@am__append_146 = -I$(srcdir)/synctexdir \ @EUPTEX_SYNCTEX_TRUE@ $(ZLIB_INCLUDES) -D__SyncTeX__ \ @EUPTEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-euptex.h\" -@EUPTEX_SYNCTEX_TRUE@am__append_146 = $(ZLIB_LIBS) -@EUPTEX_SYNCTEX_TRUE@am__append_147 = $(ZLIB_DEPEND) -@EUPTEX_SYNCTEX_TRUE@am__append_148 = \ +@EUPTEX_SYNCTEX_TRUE@am__append_147 = $(ZLIB_LIBS) +@EUPTEX_SYNCTEX_TRUE@am__append_148 = $(ZLIB_DEPEND) +@EUPTEX_SYNCTEX_TRUE@am__append_149 = \ @EUPTEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @EUPTEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @EUPTEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @EUPTEX_SYNCTEX_TRUE@ synctexdir/synctex-euptex.h -@PDFTEX_SYNCTEX_TRUE@am__append_149 = -I$(srcdir)/synctexdir \ +@PDFTEX_SYNCTEX_TRUE@am__append_150 = -I$(srcdir)/synctexdir \ @PDFTEX_SYNCTEX_TRUE@ -D__SyncTeX__ \ @PDFTEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-pdftex.h\" -@PDFTEX_SYNCTEX_TRUE@am__append_150 = \ +@PDFTEX_SYNCTEX_TRUE@am__append_151 = \ @PDFTEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @PDFTEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @PDFTEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @PDFTEX_SYNCTEX_TRUE@ synctexdir/synctex-pdftex.h -@XETEX_SYNCTEX_TRUE@am__append_151 = -I$(srcdir)/synctexdir \ +@XETEX_SYNCTEX_TRUE@am__append_152 = -I$(srcdir)/synctexdir \ @XETEX_SYNCTEX_TRUE@ -D__SyncTeX__ \ @XETEX_SYNCTEX_TRUE@ -DSYNCTEX_ENGINE_H=\"synctex-xetex.h\" -@XETEX_SYNCTEX_TRUE@am__append_152 = \ +@XETEX_SYNCTEX_TRUE@am__append_153 = \ @XETEX_SYNCTEX_TRUE@ synctexdir/synctex.c \ @XETEX_SYNCTEX_TRUE@ synctexdir/synctex.h \ @XETEX_SYNCTEX_TRUE@ synctexdir/synctex-common.h \ @XETEX_SYNCTEX_TRUE@ synctexdir/synctex-xetex.h -@SYNCTEX_TRUE@am__append_153 = $(synctex_tests) +@SYNCTEX_TRUE@am__append_154 = $(synctex_tests) subdir = . ACLOCAL_M4 = $(top_srcdir)/aclocal.m4 am__aclocal_m4_deps = $(top_srcdir)/m4/web2c-disable.m4 \ @@ -461,30 +464,32 @@ am__EXEEXT_4 = odvicopy$(EXEEXT) odvitype$(EXEEXT) otangle$(EXEEXT) \ @UPTEX_TRUE@am__EXEEXT_21 = uptex$(EXEEXT) @UPWEB_TRUE@am__EXEEXT_22 = $(am__EXEEXT_3) @EUPTEX_TRUE@am__EXEEXT_23 = euptex$(EXEEXT) -@PDFTEX_TRUE@am__EXEEXT_24 = pdftex$(EXEEXT) ttf2afm$(EXEEXT) \ +@HITEX_TRUE@am__EXEEXT_24 = hitex$(EXEEXT) hishrink$(EXEEXT) \ +@HITEX_TRUE@ histretch$(EXEEXT) +@PDFTEX_TRUE@am__EXEEXT_25 = pdftex$(EXEEXT) ttf2afm$(EXEEXT) \ @PDFTEX_TRUE@ pdftosrc$(EXEEXT) -@LUATEX_TRUE@am__EXEEXT_25 = luatex$(EXEEXT) -@LUAHBTEX_TRUE@am__EXEEXT_26 = luahbtex$(EXEEXT) -@LUAJITTEX_TRUE@am__EXEEXT_27 = luajittex$(EXEEXT) -@LUAJITHBTEX_TRUE@am__EXEEXT_28 = luajithbtex$(EXEEXT) -@XETEX_TRUE@am__EXEEXT_29 = xetex$(EXEEXT) -@OTANGLE_TRUE@am__EXEEXT_30 = $(am__EXEEXT_4) -@ALEPH_TRUE@am__EXEEXT_31 = aleph$(EXEEXT) -@SYNCTEX_TRUE@am__EXEEXT_32 = synctex$(EXEEXT) +@LUATEX_TRUE@am__EXEEXT_26 = luatex$(EXEEXT) +@LUAHBTEX_TRUE@am__EXEEXT_27 = luahbtex$(EXEEXT) +@LUAJITTEX_TRUE@am__EXEEXT_28 = luajittex$(EXEEXT) +@LUAJITHBTEX_TRUE@am__EXEEXT_29 = luajithbtex$(EXEEXT) +@XETEX_TRUE@am__EXEEXT_30 = xetex$(EXEEXT) +@OTANGLE_TRUE@am__EXEEXT_31 = $(am__EXEEXT_4) +@ALEPH_TRUE@am__EXEEXT_32 = aleph$(EXEEXT) +@SYNCTEX_TRUE@am__EXEEXT_33 = synctex$(EXEEXT) am__installdirs = "$(DESTDIR)$(bindir)" "$(DESTDIR)$(libdir)" \ "$(DESTDIR)$(libdir)" "$(DESTDIR)$(man1dir)" \ "$(DESTDIR)$(man5dir)" "$(DESTDIR)$(pkgconfigdir)" \ "$(DESTDIR)$(syncincludedir)" -@MF_TRUE@@WIN32_TRUE@am__EXEEXT_33 = call_mf$(EXEEXT) -@MFLUA_TRUE@@WIN32_TRUE@am__EXEEXT_34 = call_mflua$(EXEEXT) -@MFLUAJIT_TRUE@@WIN32_TRUE@am__EXEEXT_35 = call_mfluajit$(EXEEXT) -@MP_TRUE@@WIN32_TRUE@am__EXEEXT_36 = call_mpost$(EXEEXT) -@PMP_TRUE@@WIN32_TRUE@am__EXEEXT_37 = call_pmpost$(EXEEXT) -@UPMP_TRUE@@WIN32_TRUE@am__EXEEXT_38 = call_upmpost$(EXEEXT) -@LUATEX_TRUE@@WIN32_TRUE@am__EXEEXT_39 = call_luatex$(EXEEXT) -@LUAHBTEX_TRUE@@WIN32_TRUE@am__EXEEXT_40 = call_luahbtex$(EXEEXT) -@LUAJITTEX_TRUE@@WIN32_TRUE@am__EXEEXT_41 = call_luajittex$(EXEEXT) -@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__EXEEXT_42 = \ +@MF_TRUE@@WIN32_TRUE@am__EXEEXT_34 = call_mf$(EXEEXT) +@MFLUA_TRUE@@WIN32_TRUE@am__EXEEXT_35 = call_mflua$(EXEEXT) +@MFLUAJIT_TRUE@@WIN32_TRUE@am__EXEEXT_36 = call_mfluajit$(EXEEXT) +@MP_TRUE@@WIN32_TRUE@am__EXEEXT_37 = call_mpost$(EXEEXT) +@PMP_TRUE@@WIN32_TRUE@am__EXEEXT_38 = call_pmpost$(EXEEXT) +@UPMP_TRUE@@WIN32_TRUE@am__EXEEXT_39 = call_upmpost$(EXEEXT) +@LUATEX_TRUE@@WIN32_TRUE@am__EXEEXT_40 = call_luatex$(EXEEXT) +@LUAHBTEX_TRUE@@WIN32_TRUE@am__EXEEXT_41 = call_luahbtex$(EXEEXT) +@LUAJITTEX_TRUE@@WIN32_TRUE@am__EXEEXT_42 = call_luajittex$(EXEEXT) +@LUAJITHBTEX_TRUE@@WIN32_TRUE@am__EXEEXT_43 = \ @LUAJITHBTEX_TRUE@@WIN32_TRUE@ call_luajithbtex$(EXEEXT) PROGRAMS = $(bin_PROGRAMS) $(noinst_PROGRAMS) am__vpath_adj_setup = srcdirstrip=`echo "$(srcdir)" | sed 's|.|.|g'`; @@ -1382,12 +1387,27 @@ nodist_gftype_OBJECTS = gftype.$(OBJEXT) gftype_OBJECTS = $(nodist_gftype_OBJECTS) gftype_LDADD = $(LDADD) gftype_DEPENDENCIES = $(proglib) $(am__DEPENDENCIES_1) +nodist_hishrink_OBJECTS = hishrink-hformat.$(OBJEXT) \ + hishrink-hishrink.$(OBJEXT) hishrink-shrink-lexer.$(OBJEXT) \ + hishrink-shrink-parser.$(OBJEXT) +hishrink_OBJECTS = $(nodist_hishrink_OBJECTS) +hishrink_DEPENDENCIES = $(am__DEPENDENCIES_1) +nodist_histretch_OBJECTS = histretch-hformat.$(OBJEXT) \ + histretch-histretch.$(OBJEXT) +histretch_OBJECTS = $(nodist_histretch_OBJECTS) +histretch_DEPENDENCIES = $(am__DEPENDENCIES_1) +am__objects_37 = hitex-htex.$(OBJEXT) +am__objects_38 = hitex-hitex.$(OBJEXT) +nodist_hitex_OBJECTS = hitex-hformat.$(OBJEXT) hitex-hput.$(OBJEXT) \ + $(am__objects_37) $(am__objects_38) +hitex_OBJECTS = $(nodist_hitex_OBJECTS) +hitex_DEPENDENCIES = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) nodist_initex_OBJECTS = initex-callexe.$(OBJEXT) initex_OBJECTS = $(nodist_initex_OBJECTS) initex_DEPENDENCIES = -am__objects_37 = luatexdir/luahbtex-luatex.$(OBJEXT) \ +am__objects_39 = luatexdir/luahbtex-luatex.$(OBJEXT) \ mplibdir/luahbtex-lmplib.$(OBJEXT) -nodist_luahbtex_OBJECTS = $(am__objects_37) +nodist_luahbtex_OBJECTS = $(am__objects_39) luahbtex_OBJECTS = $(nodist_luahbtex_OBJECTS) am__DEPENDENCIES_6 = $(am__DEPENDENCIES_1) am__DEPENDENCIES_7 = libmplibcore.a $(am__DEPENDENCIES_1) \ @@ -1398,16 +1418,16 @@ am__DEPENDENCIES_7 = libmplibcore.a $(am__DEPENDENCIES_1) \ luahbtex_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CXX $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CXXLD) $(luahbtex_CXXFLAGS) \ $(CXXFLAGS) $(luahbtex_LDFLAGS) $(LDFLAGS) -o $@ -am__objects_38 = luatexdir/luajithbtex-luatex.$(OBJEXT) \ +am__objects_40 = luatexdir/luajithbtex-luatex.$(OBJEXT) \ mplibdir/luajithbtex-lmplib.$(OBJEXT) -nodist_luajithbtex_OBJECTS = $(am__objects_38) +nodist_luajithbtex_OBJECTS = $(am__objects_40) luajithbtex_OBJECTS = $(nodist_luajithbtex_OBJECTS) luajithbtex_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CXX $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CXXLD) $(luajithbtex_CXXFLAGS) \ $(CXXFLAGS) $(luajithbtex_LDFLAGS) $(LDFLAGS) -o $@ -am__objects_39 = luatexdir/luajittex-luatex.$(OBJEXT) \ +am__objects_41 = luatexdir/luajittex-luatex.$(OBJEXT) \ mplibdir/luajittex-lmplib.$(OBJEXT) -nodist_luajittex_OBJECTS = $(am__objects_39) +nodist_luajittex_OBJECTS = $(am__objects_41) luajittex_OBJECTS = $(nodist_luajittex_OBJECTS) am__DEPENDENCIES_8 = libmplibcore.a $(am__DEPENDENCIES_1) \ $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ @@ -1416,9 +1436,9 @@ am__DEPENDENCIES_8 = libmplibcore.a $(am__DEPENDENCIES_1) \ luajittex_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \ $(luajittex_LDFLAGS) $(LDFLAGS) -o $@ -am__objects_40 = luatexdir/luatex-luatex.$(OBJEXT) \ +am__objects_42 = luatexdir/luatex-luatex.$(OBJEXT) \ mplibdir/luatex-lmplib.$(OBJEXT) -nodist_luatex_OBJECTS = $(am__objects_40) +nodist_luatex_OBJECTS = $(am__objects_42) luatex_OBJECTS = $(nodist_luatex_OBJECTS) luatex_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \ @@ -1444,8 +1464,8 @@ mflua_DEPENDENCIES = libmflua.a libmfluaotfcc.a $(am__DEPENDENCIES_2) \ mflua_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \ $(mflua_LDFLAGS) $(LDFLAGS) -o $@ -am__objects_41 = mfluadir/mflua_nowin-mfluaextra.$(OBJEXT) -nodist_mflua_nowin_OBJECTS = $(am__objects_41) +am__objects_43 = mfluadir/mflua_nowin-mfluaextra.$(OBJEXT) +nodist_mflua_nowin_OBJECTS = $(am__objects_43) mflua_nowin_OBJECTS = $(nodist_mflua_nowin_OBJECTS) mflua_nowin_DEPENDENCIES = libmflua.a libmfluaotfcc.a \ $(am__DEPENDENCIES_2) $(windowlib) $(am__DEPENDENCIES_6) @@ -1460,8 +1480,8 @@ mfluajit_DEPENDENCIES = libmfluajit.a libmfluaotfcc.a \ mfluajit_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \ $(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \ $(mfluajit_LDFLAGS) $(LDFLAGS) -o $@ -am__objects_42 = mfluajitdir/mfluajit_nowin-mfluajitextra.$(OBJEXT) -nodist_mfluajit_nowin_OBJECTS = $(am__objects_42) +am__objects_44 = mfluajitdir/mfluajit_nowin-mfluajitextra.$(OBJEXT) +nodist_mfluajit_nowin_OBJECTS = $(am__objects_44) mfluajit_nowin_OBJECTS = $(nodist_mfluajit_nowin_OBJECTS) mfluajit_nowin_DEPENDENCIES = libmfluajit.a libmfluaotfcc.a \ $(am__DEPENDENCIES_2) $(windowlib) $(am__DEPENDENCIES_1) @@ -1473,8 +1493,8 @@ nodist_mft_OBJECTS = mft.$(OBJEXT) mft_OBJECTS = $(nodist_mft_OBJECTS) mft_LDADD = $(LDADD) mft_DEPENDENCIES = $(proglib) $(am__DEPENDENCIES_1) -am__objects_43 = mpost-mpxout.$(OBJEXT) -nodist_mpost_OBJECTS = mpost-mpost.$(OBJEXT) $(am__objects_43) +am__objects_45 = mpost-mpxout.$(OBJEXT) +nodist_mpost_OBJECTS = mpost-mpost.$(OBJEXT) $(am__objects_45) mpost_OBJECTS = $(nodist_mpost_OBJECTS) mpost_DEPENDENCIES = libmplibcore.a libmplibextramath.a \ libmplibbackends.a $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ @@ -1507,12 +1527,12 @@ am__dist_pdftex_SOURCES_DIST = pdftexdir/pdftexextra.c \ pdftexdir/etex_version.h synctexdir/synctex.c \ synctexdir/synctex.h synctexdir/synctex-common.h \ synctexdir/synctex-pdftex.h -@PDFTEX_SYNCTEX_TRUE@am__objects_44 = \ +@PDFTEX_SYNCTEX_TRUE@am__objects_46 = \ @PDFTEX_SYNCTEX_TRUE@ synctexdir/pdftex-synctex.$(OBJEXT) dist_pdftex_OBJECTS = pdftexdir/pdftex-pdftexextra.$(OBJEXT) \ - $(am__objects_44) -am__objects_45 = pdftex-pdftexini.$(OBJEXT) pdftex-pdftex0.$(OBJEXT) -nodist_pdftex_OBJECTS = $(am__objects_45) pdftex-pdftex-pool.$(OBJEXT) + $(am__objects_46) +am__objects_47 = pdftex-pdftexini.$(OBJEXT) pdftex-pdftex0.$(OBJEXT) +nodist_pdftex_OBJECTS = $(am__objects_47) pdftex-pdftex-pool.$(OBJEXT) pdftex_OBJECTS = $(dist_pdftex_OBJECTS) $(nodist_pdftex_OBJECTS) am__DEPENDENCIES_11 = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ $(am__DEPENDENCIES_1) libmd5.a @@ -1539,20 +1559,20 @@ nodist_pltotf_OBJECTS = pltotf.$(OBJEXT) pltotf_OBJECTS = $(nodist_pltotf_OBJECTS) pltotf_LDADD = $(LDADD) pltotf_DEPENDENCIES = $(proglib) $(am__DEPENDENCIES_1) -am__objects_46 = pmpost-pmp.$(OBJEXT) -am__objects_47 = pmpost-pmpmath.$(OBJEXT) -am__objects_48 = pmpost-pmpmathbinary.$(OBJEXT) -am__objects_49 = pmpost-pmpmathdecimal.$(OBJEXT) -am__objects_50 = pmpost-pmpmathdouble.$(OBJEXT) -am__objects_51 = pmpost-pmpstrings.$(OBJEXT) -am__objects_52 = pmpost-pmpxout.$(OBJEXT) -am__objects_53 = pmpost-ppngout.$(OBJEXT) -am__objects_54 = pmpost-ppsout.$(OBJEXT) -am__objects_55 = pmpost-psvgout.$(OBJEXT) -nodist_pmpost_OBJECTS = $(am__objects_46) $(am__objects_47) \ - $(am__objects_48) $(am__objects_49) $(am__objects_50) \ - pmpost-pmpost.$(OBJEXT) $(am__objects_51) $(am__objects_52) \ - $(am__objects_53) $(am__objects_54) $(am__objects_55) \ +am__objects_48 = pmpost-pmp.$(OBJEXT) +am__objects_49 = pmpost-pmpmath.$(OBJEXT) +am__objects_50 = pmpost-pmpmathbinary.$(OBJEXT) +am__objects_51 = pmpost-pmpmathdecimal.$(OBJEXT) +am__objects_52 = pmpost-pmpmathdouble.$(OBJEXT) +am__objects_53 = pmpost-pmpstrings.$(OBJEXT) +am__objects_54 = pmpost-pmpxout.$(OBJEXT) +am__objects_55 = pmpost-ppngout.$(OBJEXT) +am__objects_56 = pmpost-ppsout.$(OBJEXT) +am__objects_57 = pmpost-psvgout.$(OBJEXT) +nodist_pmpost_OBJECTS = $(am__objects_48) $(am__objects_49) \ + $(am__objects_50) $(am__objects_51) $(am__objects_52) \ + pmpost-pmpost.$(OBJEXT) $(am__objects_53) $(am__objects_54) \ + $(am__objects_55) $(am__objects_56) $(am__objects_57) \ pmpost-ptfmin.$(OBJEXT) pmpost_OBJECTS = $(nodist_pmpost_OBJECTS) pmpost_DEPENDENCIES = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ @@ -1570,10 +1590,10 @@ am__dist_ptex_SOURCES_DIST = ptexdir/ptexextra.c ptexdir/ptexextra.h \ ptexdir/ptex_version.h synctexdir/synctex.c \ synctexdir/synctex.h synctexdir/synctex-common.h \ synctexdir/synctex-ptex.h -@PTEX_SYNCTEX_TRUE@am__objects_56 = synctexdir/ptex-synctex.$(OBJEXT) -dist_ptex_OBJECTS = ptexdir/ptex-ptexextra.$(OBJEXT) $(am__objects_56) -am__objects_57 = ptex-ptexini.$(OBJEXT) ptex-ptex0.$(OBJEXT) -nodist_ptex_OBJECTS = $(am__objects_57) ptex-ptex-pool.$(OBJEXT) +@PTEX_SYNCTEX_TRUE@am__objects_58 = synctexdir/ptex-synctex.$(OBJEXT) +dist_ptex_OBJECTS = ptexdir/ptex-ptexextra.$(OBJEXT) $(am__objects_58) +am__objects_59 = ptex-ptexini.$(OBJEXT) ptex-ptex0.$(OBJEXT) +nodist_ptex_OBJECTS = $(am__objects_59) ptex-ptex-pool.$(OBJEXT) ptex_OBJECTS = $(dist_ptex_OBJECTS) $(nodist_ptex_OBJECTS) @PTEX_SYNCTEX_TRUE@am__DEPENDENCIES_12 = $(am__DEPENDENCIES_1) am_ptftopl_OBJECTS = @@ -1594,10 +1614,10 @@ tangleboot_LDADD = $(LDADD) am__dist_tex_SOURCES_DIST = texextra.c synctexdir/synctex.c \ synctexdir/synctex.h synctexdir/synctex-common.h \ synctexdir/synctex-tex.h -@TEX_SYNCTEX_TRUE@am__objects_58 = synctexdir/tex-synctex.$(OBJEXT) -dist_tex_OBJECTS = tex-texextra.$(OBJEXT) $(am__objects_58) -am__objects_59 = tex-texini.$(OBJEXT) tex-tex0.$(OBJEXT) -nodist_tex_OBJECTS = $(am__objects_59) tex-tex-pool.$(OBJEXT) +@TEX_SYNCTEX_TRUE@am__objects_60 = synctexdir/tex-synctex.$(OBJEXT) +dist_tex_OBJECTS = tex-texextra.$(OBJEXT) $(am__objects_60) +am__objects_61 = tex-texini.$(OBJEXT) tex-tex0.$(OBJEXT) +nodist_tex_OBJECTS = $(am__objects_61) tex-tex-pool.$(OBJEXT) tex_OBJECTS = $(dist_tex_OBJECTS) $(nodist_tex_OBJECTS) @TEX_SYNCTEX_TRUE@am__DEPENDENCIES_14 = $(am__DEPENDENCIES_1) tex_DEPENDENCIES = $(am__DEPENDENCIES_2) $(am__DEPENDENCIES_1) \ @@ -1622,21 +1642,21 @@ am_updvitype_OBJECTS = nodist_updvitype_OBJECTS = updvitype-updvitype.$(OBJEXT) updvitype_OBJECTS = $(am_updvitype_OBJECTS) \ $(nodist_updvitype_OBJECTS) -am__objects_60 = upmpost-pmp.$(OBJEXT) -am__objects_61 = upmpost-pmpmath.$(OBJEXT) -am__objects_62 = upmpost-pmpmathbinary.$(OBJEXT) -am__objects_63 = upmpost-pmpmathdecimal.$(OBJEXT) -am__objects_64 = upmpost-pmpmathdouble.$(OBJEXT) -am__objects_65 = upmpost-pmpstrings.$(OBJEXT) -am__objects_66 = upmpost-pmpxout.$(OBJEXT) -am__objects_67 = upmpost-ppngout.$(OBJEXT) -am__objects_68 = upmpost-ppsout.$(OBJEXT) -am__objects_69 = upmpost-psvgout.$(OBJEXT) -am__objects_70 = $(am__objects_60) $(am__objects_61) $(am__objects_62) \ - $(am__objects_63) $(am__objects_64) upmpost-pmpost.$(OBJEXT) \ - $(am__objects_65) $(am__objects_66) $(am__objects_67) \ - $(am__objects_68) $(am__objects_69) upmpost-ptfmin.$(OBJEXT) -nodist_upmpost_OBJECTS = $(am__objects_70) +am__objects_62 = upmpost-pmp.$(OBJEXT) +am__objects_63 = upmpost-pmpmath.$(OBJEXT) +am__objects_64 = upmpost-pmpmathbinary.$(OBJEXT) +am__objects_65 = upmpost-pmpmathdecimal.$(OBJEXT) +am__objects_66 = upmpost-pmpmathdouble.$(OBJEXT) +am__objects_67 = upmpost-pmpstrings.$(OBJEXT) +am__objects_68 = upmpost-pmpxout.$(OBJEXT) +am__objects_69 = upmpost-ppngout.$(OBJEXT) +am__objects_70 = upmpost-ppsout.$(OBJEXT) +am__objects_71 = upmpost-psvgout.$(OBJEXT) +am__objects_72 = $(am__objects_62) $(am__objects_63) $(am__objects_64) \ + $(am__objects_65) $(am__objects_66) upmpost-pmpost.$(OBJEXT) \ + $(am__objects_67) $(am__objects_68) $(am__objects_69) \ + $(am__objects_70) $(am__objects_71) upmpost-ptfmin.$(OBJEXT) +nodist_upmpost_OBJECTS = $(am__objects_72) upmpost_OBJECTS = $(nodist_upmpost_OBJECTS) am__DEPENDENCIES_16 = $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ $(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \ @@ -1650,12 +1670,12 @@ am__dist_uptex_SOURCES_DIST = uptexdir/uptexextra.c \ uptexdir/uptexextra.h uptexdir/uptex_version.h \ synctexdir/synctex.c synctexdir/synctex.h \ synctexdir/synctex-common.h synctexdir/synctex-uptex.h -@UPTEX_SYNCTEX_TRUE@am__objects_71 = \ +@UPTEX_SYNCTEX_TRUE@am__objects_73 = \ @UPTEX_SYNCTEX_TRUE@ synctexdir/uptex-synctex.$(OBJEXT) dist_uptex_OBJECTS = uptexdir/uptex-uptexextra.$(OBJEXT) \ - $(am__objects_71) -am__objects_72 = uptex-uptexini.$(OBJEXT) uptex-uptex0.$(OBJEXT) -nodist_uptex_OBJECTS = $(am__objects_72) uptex-uptex-pool.$(OBJEXT) + $(am__objects_73) +am__objects_74 = uptex-uptexini.$(OBJEXT) uptex-uptex0.$(OBJEXT) +nodist_uptex_OBJECTS = $(am__objects_74) uptex-uptex-pool.$(OBJEXT) uptex_OBJECTS = $(dist_uptex_OBJECTS) $(nodist_uptex_OBJECTS) @UPTEX_SYNCTEX_TRUE@am__DEPENDENCIES_17 = $(am__DEPENDENCIES_1) am_uptftopl_OBJECTS = @@ -1694,12 +1714,12 @@ am__dist_xetex_SOURCES_DIST = xetexdir/xetexextra.c \ xetexdir/xetex_version.h synctexdir/synctex.c \ synctexdir/synctex.h synctexdir/synctex-common.h \ synctexdir/synctex-xetex.h -@XETEX_SYNCTEX_TRUE@am__objects_73 = \ +@XETEX_SYNCTEX_TRUE@am__objects_75 = \ @XETEX_SYNCTEX_TRUE@ synctexdir/xetex-synctex.$(OBJEXT) dist_xetex_OBJECTS = xetexdir/xetex-xetexextra.$(OBJEXT) \ - $(am__objects_73) -am__objects_74 = xetex-xetexini.$(OBJEXT) xetex-xetex0.$(OBJEXT) -nodist_xetex_OBJECTS = $(am__objects_74) xetex-xetex-pool.$(OBJEXT) + $(am__objects_75) +am__objects_76 = xetex-xetexini.$(OBJEXT) xetex-xetex0.$(OBJEXT) +nodist_xetex_OBJECTS = $(am__objects_76) xetex-xetex-pool.$(OBJEXT) xetex_OBJECTS = $(dist_xetex_OBJECTS) $(nodist_xetex_OBJECTS) @XETEX_MACOSX_FALSE@am__DEPENDENCIES_18 = $(am__DEPENDENCIES_1) am__DEPENDENCIES_19 = $(libxetex) $(am__DEPENDENCIES_1) \ @@ -1750,7 +1770,15 @@ am__depfiles_remade = ./$(DEPDIR)/aleph-aleph-pool.Po \ ./$(DEPDIR)/euptex-euptex-pool.Po \ ./$(DEPDIR)/euptex-euptex0.Po ./$(DEPDIR)/euptex-euptexini.Po \ ./$(DEPDIR)/gftodvi.Po ./$(DEPDIR)/gftopk.Po \ - ./$(DEPDIR)/gftype.Po ./$(DEPDIR)/initex-callexe.Po \ + ./$(DEPDIR)/gftype.Po ./$(DEPDIR)/hishrink-hformat.Po \ + ./$(DEPDIR)/hishrink-hishrink.Po \ + ./$(DEPDIR)/hishrink-shrink-lexer.Po \ + ./$(DEPDIR)/hishrink-shrink-parser.Po \ + ./$(DEPDIR)/histretch-hformat.Po \ + ./$(DEPDIR)/histretch-histretch.Po \ + ./$(DEPDIR)/hitex-hformat.Po ./$(DEPDIR)/hitex-hitex.Po \ + ./$(DEPDIR)/hitex-hput.Po ./$(DEPDIR)/hitex-htex.Po \ + ./$(DEPDIR)/initex-callexe.Po \ ./$(DEPDIR)/libluahbtexspecific_a-luainit-hb.Po \ ./$(DEPDIR)/libluahbtexspecific_a-luastuff-hb.Po \ ./$(DEPDIR)/libluahbtexspecific_a-printing-hb.Po \ @@ -2433,6 +2461,15 @@ AM_V_CXXLD = $(am__v_CXXLD_@AM_V@) am__v_CXXLD_ = $(am__v_CXXLD_@AM_DEFAULT_V@) am__v_CXXLD_0 = @echo " CXXLD " $@; am__v_CXXLD_1 = +@MAINTAINER_MODE_FALSE@am__skiplex = test -f $@ || +LEXCOMPILE = $(LEX) $(AM_LFLAGS) $(LFLAGS) +LTLEXCOMPILE = $(LIBTOOL) $(AM_V_lt) $(AM_LIBTOOLFLAGS) \ + $(LIBTOOLFLAGS) --mode=compile $(LEX) $(AM_LFLAGS) $(LFLAGS) +AM_V_LEX = $(am__v_LEX_@AM_V@) +am__v_LEX_ = $(am__v_LEX_@AM_DEFAULT_V@) +am__v_LEX_0 = @echo " LEX " $@; +am__v_LEX_1 = +YLWRAP = $(top_srcdir)/../../build-aux/ylwrap OBJCXXCOMPILE = $(OBJCXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) \ $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_OBJCXXFLAGS) $(OBJCXXFLAGS) LTOBJCXXCOMPILE = $(LIBTOOL) $(AM_V_lt) $(AM_LIBTOOLFLAGS) \ @@ -2451,6 +2488,16 @@ AM_V_OBJCXXLD = $(am__v_OBJCXXLD_@AM_V@) am__v_OBJCXXLD_ = $(am__v_OBJCXXLD_@AM_DEFAULT_V@) am__v_OBJCXXLD_0 = @echo " OBJCXXLD" $@; am__v_OBJCXXLD_1 = +@MAINTAINER_MODE_FALSE@am__skipyacc = test -f $@ || +am__yacc_c2h = sed -e s/cc$$/hh/ -e s/cpp$$/hpp/ -e s/cxx$$/hxx/ \ + -e s/c++$$/h++/ -e s/c$$/h/ +YACCCOMPILE = $(YACC) $(AM_YFLAGS) $(YFLAGS) +LTYACCCOMPILE = $(LIBTOOL) $(AM_V_lt) $(AM_LIBTOOLFLAGS) \ + $(LIBTOOLFLAGS) --mode=compile $(YACC) $(AM_YFLAGS) $(YFLAGS) +AM_V_YACC = $(am__v_YACC_@AM_V@) +am__v_YACC_ = $(am__v_YACC_@AM_DEFAULT_V@) +am__v_YACC_0 = @echo " YACC " $@; +am__v_YACC_1 = SOURCES = $(libff_a_SOURCES) $(libkanji_a_SOURCES) \ $(nodist_libluaffi_a_SOURCES) $(libluaharfbuzz_a_SOURCES) \ $(nodist_libluahbtexspecific_a_SOURCES) \ @@ -2493,8 +2540,10 @@ SOURCES = $(libff_a_SOURCES) $(libkanji_a_SOURCES) \ $(dist_euptex_SOURCES) $(nodist_euptex_SOURCES) \ $(gftodvi_SOURCES) $(nodist_gftodvi_SOURCES) \ $(nodist_gftopk_SOURCES) $(nodist_gftype_SOURCES) \ - $(nodist_initex_SOURCES) $(nodist_luahbtex_SOURCES) \ - $(nodist_EXTRA_luahbtex_SOURCES) $(nodist_luajithbtex_SOURCES) \ + $(nodist_hishrink_SOURCES) $(nodist_histretch_SOURCES) \ + $(nodist_hitex_SOURCES) $(nodist_initex_SOURCES) \ + $(nodist_luahbtex_SOURCES) $(nodist_EXTRA_luahbtex_SOURCES) \ + $(nodist_luajithbtex_SOURCES) \ $(nodist_EXTRA_luajithbtex_SOURCES) \ $(nodist_luajittex_SOURCES) $(nodist_luatex_SOURCES) \ $(md5main_SOURCES) $(dist_mf_SOURCES) $(dist_mf_nowin_SOURCES) \ @@ -2755,14 +2804,14 @@ am__set_TESTS_bases = \ bases=`echo $$bases` AM_TESTSUITE_SUMMARY_HEADER = ' for $(PACKAGE_STRING)' RECHECK_LOGS = $(TEST_LOGS) -am__EXEEXT_43 = bibtex.test dvicopy.test dvitype.test gftodvi.test \ +am__EXEEXT_44 = bibtex.test dvicopy.test dvitype.test gftodvi.test \ gftopk.test gftype.test mft.test patgen.test pktogf.test \ pktype.test pltotf.test pooltype.test tftopl.test vftovp.test \ vptovf.test weave.test -am__EXEEXT_44 = $(am__EXEEXT_43) tests/bibtex-openout-test.pl \ +am__EXEEXT_45 = $(am__EXEEXT_44) tests/bibtex-openout-test.pl \ tests/bibtex-longline-test.pl tests/bibtex-mem.test \ tests/bibtex-bigauth.test tests/bibtex-auxinclude.test -@WEB_TRUE@am__EXEEXT_45 = $(am__EXEEXT_44) +@WEB_TRUE@am__EXEEXT_46 = $(am__EXEEXT_45) TEST_SUITE_LOG = test-suite.log am__test_logs1 = $(TESTS:=.log) am__test_logs2 = $(am__test_logs1:@EXEEXT@.log=.log) @@ -2790,7 +2839,8 @@ am__DIST_COMMON = $(dist_man_MANS) $(srcdir)/../../am/bin_links.am \ $(srcdir)/am/cweb.am $(srcdir)/am/texmf.am $(srcdir)/am/web.am \ $(srcdir)/c-auto.in $(srcdir)/ctangleboot-sh.in \ $(srcdir)/eptexdir/am/eptex.am $(srcdir)/etexdir/am/etex.am \ - $(srcdir)/euptexdir/am/euptex.am $(srcdir)/libmd5/am/md5.am \ + $(srcdir)/euptexdir/am/euptex.am \ + $(srcdir)/hitexdir/am/hitex.am $(srcdir)/libmd5/am/md5.am \ $(srcdir)/luatexdir/am/libluatex.am \ $(srcdir)/luatexdir/am/libunilib.am \ $(srcdir)/luatexdir/am/luaffi.am \ @@ -2822,6 +2872,7 @@ am__DIST_COMMON = $(dist_man_MANS) $(srcdir)/../../am/bin_links.am \ $(top_srcdir)/../../build-aux/ltmain.sh \ $(top_srcdir)/../../build-aux/missing \ $(top_srcdir)/../../build-aux/test-driver \ + $(top_srcdir)/../../build-aux/ylwrap \ $(top_srcdir)/../texlive/w32_wrapper/callexe.c \ $(top_srcdir)/luatexdir/luafontloader/ff-config.in \ $(top_srcdir)/synctexdir/synctex.pc.in ../../build-aux/ar-lib \ @@ -2985,7 +3036,7 @@ NM = @NM@ NMEDIT = @NMEDIT@ OBJCXX = @OBJCXX@ OBJCXXDEPMODE = @OBJCXXDEPMODE@ -OBJCXXFLAGS = @OBJCXXFLAGS@ $(am__append_110) +OBJCXXFLAGS = @OBJCXXFLAGS@ $(am__append_111) OBJDUMP = @OBJDUMP@ OBJEXT = @OBJEXT@ OTANGLE = @OTANGLE@ @@ -3127,8 +3178,8 @@ EXTRA_LIBRARIES = libmf.a libmflua.a libmfluaotfcc.a libmfluaotfcc.a \ libluajithbtexspecific.a libluaffi.a libluaharfbuzz.a \ libluajitharfbuzz.a libxetex.a libsynctex.a libmd5.a EXTRA_LTLIBRARIES = libsynctex.la -lib_LIBRARIES = $(am__append_122) -lib_LTLIBRARIES = $(am__append_121) +lib_LIBRARIES = $(am__append_123) +lib_LTLIBRARIES = $(am__append_122) dist_man_MANS = synctexdir/man1/synctex.1 synctexdir/man5/synctex.5 nodist_man_MANS = TEST_EXTENSIONS = .pl .test @@ -3245,21 +3296,21 @@ EXTRA_DIST = PROJECTS cftests cpascal.h help.h w2c/config.h \ euptexdir/euptrip/euptrip.diffs euptexdir/euptrip/texmf.cnf \ euptexdir/pdfprimitive.test \ eptexdir/tests/pdfprimitive-test.tex \ - euptexdir/tests/pdfprimitive-euptex.log \ - pdftexdir/regex/COPYING.LIB pdftexdir/regex/README \ - $(pdftex_ch_srcs) pdftexdir/pdftex.defines pdftexdir/ChangeLog \ - pdftexdir/NEWS pdftexdir/README pdftexdir/change-files.txt \ - $(pdftex_tests) tests/wprob.tex pdftexdir/tests/pdfimage.tex \ - tests/1-4.jpg tests/B.pdf tests/basic.tex \ - tests/lily-ledger-broken.png tests/expanded.tex \ - tests/expanded.txt tests/cnfline.tex tests/partoken-ok.tex \ - tests/partoken-xfail.tex $(ttf2afm_tests) \ - pdftexdir/tests/postV3.afm pdftexdir/tests/postV3.ttf \ - pdftexdir/tests/postV7.afm pdftexdir/tests/postV7.ttf \ - $(pdftosrc_tests) pdftexdir/tests/test-13.pdf \ - pdftexdir/tests/test-13.xref pdftexdir/tests/test-15.pdf \ - pdftexdir/tests/test-15.xref $(libluasocket_sources) \ - luatexdir/luasocket/src/ftp_lua.c \ + euptexdir/tests/pdfprimitive-euptex.log hitexdir/ChangeLog \ + $(hitex_web) lex.sed yacc.sed pdftexdir/regex/COPYING.LIB \ + pdftexdir/regex/README $(pdftex_ch_srcs) \ + pdftexdir/pdftex.defines pdftexdir/ChangeLog pdftexdir/NEWS \ + pdftexdir/README pdftexdir/change-files.txt $(pdftex_tests) \ + tests/wprob.tex pdftexdir/tests/pdfimage.tex tests/1-4.jpg \ + tests/B.pdf tests/basic.tex tests/lily-ledger-broken.png \ + tests/expanded.tex tests/expanded.txt tests/cnfline.tex \ + tests/partoken-ok.tex tests/partoken-xfail.tex \ + $(ttf2afm_tests) pdftexdir/tests/postV3.afm \ + pdftexdir/tests/postV3.ttf pdftexdir/tests/postV7.afm \ + pdftexdir/tests/postV7.ttf $(pdftosrc_tests) \ + pdftexdir/tests/test-13.pdf pdftexdir/tests/test-13.xref \ + pdftexdir/tests/test-15.pdf pdftexdir/tests/test-15.xref \ + $(libluasocket_sources) luatexdir/luasocket/src/ftp_lua.c \ luatexdir/luasocket/src/headers_lua.c \ luatexdir/luasocket/src/http_lua.c \ luatexdir/luasocket/src/ltn12_lua.c \ @@ -3568,7 +3619,10 @@ DISTCLEANFILES = CXXLD.sh tangle.c tangle.h tangle.p tangle-web2c \ uptests/yuparse.* uptests/ygkhuge*.* uptrip.diffs \ $(nodist_euptex_SOURCES) euptex.web euptex.ch euptex-web2c \ euptex.p euptex.pool euptex-tangle euptrip.diffs \ - pdfprimitive-euptex.* $(nodist_pdftex_SOURCES) pdftex-final.ch \ + pdfprimitive-euptex.* $(nodist_hitex_SOURCES) \ + $(nodist_hishrink_SOURCES) $(nodist_histretch_SOURCES) \ + format-tangle htex-tangle hitex-tangle shrink-parser.* \ + shrink-lexer.* $(nodist_pdftex_SOURCES) pdftex-final.ch \ pdftex-web2c pdftex.p pdftex.pool pdftex-tangle pwprob.log \ pwprob.tex pdfimage.fmt pdfimage.log pdfimage.pdf expanded.log \ cnfline.log partoken-ok.log partoken-xfail.log postV3.afm \ @@ -3607,16 +3661,16 @@ TRIPTRAP = $(am__append_7) $(am__append_17) $(am__append_26) \ $(am__append_79) bin_links = $(am__append_5) $(am__append_14) $(am__append_15) \ $(am__append_24) $(am__append_33) $(am__append_41) \ - $(am__append_49) $(am__append_54) $(am__append_88) \ - $(am__append_93) $(am__append_98) $(am__append_103) + $(am__append_49) $(am__append_54) $(am__append_89) \ + $(am__append_94) $(am__append_99) $(am__append_104) install_exe_links = $(am__append_12) $(am__append_22) $(am__append_31) \ $(am__append_39) $(am__append_47) $(am__append_52) \ - $(am__append_86) $(am__append_91) $(am__append_96) \ - $(am__append_101) + $(am__append_87) $(am__append_92) $(am__append_97) \ + $(am__append_102) uninstall_exe_links = $(am__append_13) $(am__append_23) \ $(am__append_32) $(am__append_40) $(am__append_48) \ - $(am__append_53) $(am__append_87) $(am__append_92) \ - $(am__append_97) $(am__append_102) + $(am__append_53) $(am__append_88) $(am__append_93) \ + $(am__append_98) $(am__append_103) NEVER_DIST = `find . $(NEVER_NAMES)` cwebdir/cweave.log \ cwebdir/cweave.trs cwebdir/ctwill.log cwebdir/ctwill.trs \ cwebdir/refsort.log cwebdir/refsort.trs cwebdir/twinx.log \ @@ -3787,18 +3841,18 @@ tie_CPPFLAGS = $(AM_CPPFLAGS) -DNOT_WEB2C initex_CPPFLAGS = -DEXEPROG=\"tex.exe\" nodist_initex_SOURCES = callexe.c initex_LDADD = -tex_CPPFLAGS = $(AM_CPPFLAGS) $(am__append_125) +tex_CPPFLAGS = $(AM_CPPFLAGS) $(am__append_126) # With --enable-ipc, TeX may need to link with -lsocket. -tex_LDADD = $(LDADD) $(ipc_socketlibs) $(am__append_126) +tex_LDADD = $(LDADD) $(ipc_socketlibs) $(am__append_127) # TeX C sources tex_c_h = texini.c tex0.c texcoerce.h texd.h nodist_tex_SOURCES = $(tex_c_h) tex-pool.c -dist_tex_SOURCES = texextra.c $(am__append_128) +dist_tex_SOURCES = texextra.c $(am__append_129) # We must create texd.h before building the tex_OBJECTS. -tex_prereq = texd.h $(am__append_127) +tex_prereq = texd.h $(am__append_128) tex_ch_srcs = \ tex.web \ tex.ch \ @@ -4274,21 +4328,21 @@ libmplib_web = mplibdir/mp.w mplibdir/psout.w mplibdir/svgout.w \ mplibdir/pngout.w mplibdir/mpmath.w mplibdir/mpmathbinary.w \ mplibdir/mpmathdecimal.w mplibdir/mpmathdouble.w \ mplibdir/mpstrings.w mplibdir/tfmin.w -etex_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) $(am__append_129) +etex_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) $(am__append_130) # With --enable-ipc, e-TeX may need to link with -lsocket. -etex_LDADD = $(LDADD) $(ZLIB_LIBS) $(ipc_socketlibs) $(am__append_130) +etex_LDADD = $(LDADD) $(ZLIB_LIBS) $(ipc_socketlibs) $(am__append_131) etex_DEPENDENCIES = $(ZLIB_DEPEND) # e-TeX C sources etex_c_h = etexini.c etex0.c etexcoerce.h etexd.h nodist_etex_SOURCES = $(etex_c_h) etex-pool.c dist_etex_SOURCES = etexdir/etexextra.c etexdir/etexextra.h \ - etexdir/etex_version.h $(am__append_132) + etexdir/etex_version.h $(am__append_133) # We must create etexd.h and etexdir/etex_version.h before building the # etex_OBJECTS. -etex_prereq = etexd.h etexdir/etex_version.h $(am__append_131) +etex_prereq = etexd.h etexdir/etex_version.h $(am__append_132) etex_web_srcs = \ tex.web \ etexdir/etex.ch @@ -4317,20 +4371,20 @@ pweb_programs = pbibtex pdvitype ppltotf ptftopl pproglib = lib/libp.a libkanji_a_SOURCES = ptexdir/kanji.c ptexdir/kanji.h ptexdir/kanji_dump.c libkanji_a_CPPFLAGS = $(ptex_cppflags) -ptex_CPPFLAGS = $(ptex_cppflags) $(am__append_133) +ptex_CPPFLAGS = $(ptex_cppflags) $(am__append_134) # With --enable-ipc, pTeX may need to link with -lsocket. -ptex_LDADD = $(ptex_ldadd) $(ipc_socketlibs) $(am__append_134) +ptex_LDADD = $(ptex_ldadd) $(ipc_socketlibs) $(am__append_135) ptex_DEPENDENCIES = $(ptex_dependencies) # pTeX C sources ptex_c_h = ptexini.c ptex0.c ptexcoerce.h ptexd.h nodist_ptex_SOURCES = $(ptex_c_h) ptex-pool.c dist_ptex_SOURCES = ptexdir/ptexextra.c ptexdir/ptexextra.h \ - ptexdir/ptex_version.h $(am__append_136) + ptexdir/ptex_version.h $(am__append_137) # We must create ptexd.h and ptexdir/ptex_version.h before building the ptex_OBJECTS. -ptex_prereq = ptexd.h ptexdir/ptex_version.h $(am__append_135) +ptex_prereq = ptexd.h ptexdir/ptex_version.h $(am__append_136) ptex_web_srcs = \ tex.web \ tex.ch \ @@ -4374,22 +4428,22 @@ pweb_tests = ptexdir/pbibtex.test ptexdir/pdvitype.test \ ptexdir/nissya.test ptexdir/sample.test ptexdir/yokotate.test \ ptexdir/skipjfmp.test eptex_CPPFLAGS = $(PTEXENC_INCLUDES) $(AM_CPPFLAGS) -I$(srcdir)/libmd5 \ - $(ZLIB_INCLUDES) $(am__append_141) + $(ZLIB_INCLUDES) $(am__append_142) # With --enable-ipc, e-pTeX may need to link with -lsocket. eptex_LDADD = libkanji.a $(pproglib) $(PTEXENC_LIBS) $(LDADD) \ - $(ipc_socketlibs) libmd5.a $(ZLIB_LIBS) $(am__append_142) + $(ipc_socketlibs) libmd5.a $(ZLIB_LIBS) $(am__append_143) eptex_DEPENDENCIES = libkanji.a $(pproglib) $(PTEXENC_DEPEND) $(default_dependencies) libmd5.a $(ZLIB_DEPEND) # e-pTeX C sources eptex_c_h = eptexini.c eptex0.c eptexcoerce.h eptexd.h nodist_eptex_SOURCES = $(eptex_c_h) eptex-pool.c dist_eptex_SOURCES = eptexdir/eptexextra.c eptexdir/eptexextra.h \ - eptexdir/eptex_version.h $(am__append_144) + eptexdir/eptex_version.h $(am__append_145) # We must create eptexd.h and eptexdir/eptex_version.h before building the eptex_OBJECTS. eptex_prereq = eptexd.h etexdir/etex_version.h ptexdir/ptex_version.h \ - eptexdir/eptex_version.h $(am__append_143) + eptexdir/eptex_version.h $(am__append_144) eptex_web_srcs = \ tex.web \ etexdir/etex.ch \ @@ -4423,21 +4477,21 @@ up_tangle = $(tangle_silent)WEBINPUTS=.:$(srcdir)/uptexdir:$(srcdir) $(buildenv) upweb_programs = upbibtex updvitype uppltotf uptftopl libukanji_a_SOURCES = uptexdir/kanji.c uptexdir/kanji.h uptexdir/kanji_dump.c libukanji_a_CPPFLAGS = $(uptex_cppflags) -uptex_CPPFLAGS = $(uptex_cppflags) $(am__append_137) +uptex_CPPFLAGS = $(uptex_cppflags) $(am__append_138) # With --enable-ipc, upTeX may need to link with -lsocket. -uptex_LDADD = $(uptex_ldadd) $(ipc_socketlibs) $(am__append_138) +uptex_LDADD = $(uptex_ldadd) $(ipc_socketlibs) $(am__append_139) uptex_DEPENDENCIES = $(uptex_dependencies) # upTeX C sources uptex_c_h = uptexini.c uptex0.c uptexcoerce.h uptexd.h nodist_uptex_SOURCES = $(uptex_c_h) uptex-pool.c dist_uptex_SOURCES = uptexdir/uptexextra.c uptexdir/uptexextra.h \ - uptexdir/uptex_version.h $(am__append_140) + uptexdir/uptex_version.h $(am__append_141) # We must create uptexd.h and uptexdir/uptex_version.h before building the uptex_OBJECTS. uptex_prereq = uptexd.h ptexdir/ptex_version.h \ - uptexdir/uptex_version.h $(am__append_139) + uptexdir/uptex_version.h $(am__append_140) uptex_web_srcs = \ tex.web \ tex.ch \ @@ -4485,23 +4539,23 @@ upweb_tests = \ uptexdir/gkhuge.test euptex_CPPFLAGS = $(PTEXENC_INCLUDES) $(AM_CPPFLAGS) \ - -I$(srcdir)/libmd5 $(ZLIB_INCLUDES) $(am__append_145) + -I$(srcdir)/libmd5 $(ZLIB_INCLUDES) $(am__append_146) # With --enable-ipc, e-upTeX may need to link with -lsocket. euptex_LDADD = libukanji.a $(pproglib) $(PTEXENC_LIBS) $(LDADD) \ - $(ipc_socketlibs) libmd5.a $(ZLIB_LIBS) $(am__append_146) + $(ipc_socketlibs) libmd5.a $(ZLIB_LIBS) $(am__append_147) euptex_DEPENDENCIES = libukanji.a $(pproglib) $(PTEXENC_DEPEND) $(default_dependencies) libmd5.a $(ZLIB_DEPEND) # e-upTeX C sources euptex_c_h = euptexini.c euptex0.c euptexcoerce.h euptexd.h nodist_euptex_SOURCES = $(euptex_c_h) euptex-pool.c dist_euptex_SOURCES = euptexdir/euptexextra.c euptexdir/euptexextra.h \ - $(am__append_148) + $(am__append_149) # We must create euptexd.h and [eu]ptexdir/[eu]ptex_version.h before building the euptex_OBJECTS. euptex_prereq = euptexd.h etexdir/etex_version.h \ ptexdir/ptex_version.h eptexdir/eptex_version.h \ - uptexdir/uptex_version.h $(am__append_147) + uptexdir/uptex_version.h $(am__append_148) euptex_web_srcs = \ tex.web \ etexdir/etex.ch \ @@ -4532,6 +4586,47 @@ euptex_ch_srcs = \ # e-upTeX Tests # euptex_tests = euptexdir/euptriptest.test euptexdir/pdfprimitive.test euptexdir/eupver.test + +#kb hitex_CFLAGS = $(AM_CFLAGS) \ +#kb -Wno-parentheses -Wno-maybe-uninitialized -Wno-unused-function -Wno-unused-variable +hitex_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +hitex_LDADD = $(KPATHSEA_LIBS) $(ZLIB_LIBS) +# +histretch_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +histretch_LDADD = $(ZLIB_LIBS) +# +hishrink_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +hishrink_LDADD = $(ZLIB_LIBS) + +# We want debugging for the parser, and we use features not in POSIX yacc. +# I guess the result is that we assume bison? Not sure if that's ok. +AM_YFLAGS = -d -v -Wno-yacc + +# HiTeX CWEB sources +hitex_web = hitexdir/format.w hitexdir/htex.w hitexdir/hitex.w + +# Creating several files: need stamp file and two rules with identical recipes +hi_ctangle_sh = CWEBINPUTS=$(srcdir)/hitexdir AM_V_P=$(AM_V_P) $(SHELL) ./tangle-sh $@ $(CTANGLE) + +# HiTeX C/yacc/lex sources generated using ctangle. +# For each cweb (.w) source file, list the files generated. +format_c_h_l_y = basetypes.h error.h hformat.h \ + mkhformat.c \ + hput.c hput.h \ + hget.c hget.h \ + shrink.lex-in shrink.yacc-in \ + hishrink.c histretch.c + +htex_c_h = htex.c htex.h +hitex_c_h = hitex.c hitex.h + +# Other web2c/*dir/am/*.am engine Makefile fragments define a bunch of +# _OBJECTS variables. This does not seem right to me. Instead, we +# correctly define the _SOURCES. +# +nodist_hitex_SOURCES = hformat.c hput.c $(htex_c_h) $(hitex_c_h) +nodist_histretch_SOURCES = hformat.c histretch.c +nodist_hishrink_SOURCES = hformat.c hishrink.c shrink-lexer.l shrink-parser.y libpdftex_a_CPPFLAGS = $(REGEX_INCLUDES) $(pdftex_cppflags) libpdftex_a_CXXFLAGS = $(WARNING_CXXFLAGS) libpdftex_a_SOURCES = pdftexdir/avl.c pdftexdir/avl.h \ @@ -4545,7 +4640,7 @@ libpdftex_a_SOURCES = pdftexdir/avl.c pdftexdir/avl.h \ pdftexdir/writejbig2.c pdftexdir/writejpg.c \ pdftexdir/writepng.c pdftexdir/writet1.c pdftexdir/writet3.c \ pdftexdir/writettf.c pdftexdir/writettf.h pdftexdir/writezip.c \ - $(am__append_81) + $(am__append_82) @MINGW32_TRUE@REGEX_INCLUDES = -I$(srcdir)/pdftexdir/regex EXTRA_libpdftex_a_SOURCES = pdftexdir/macnames.c \ pdftexdir/regex/regcomp.c pdftexdir/regex/regex_internal.c \ @@ -4561,7 +4656,7 @@ pdftex_dependencies = $(proglib) $(KPATHSEA_DEPEND) $(LIBPNG_DEPEND) \ # Force Automake to use CXXLD for linking nodist_EXTRA_pdftex_SOURCES = dummy.cxx pdf_tangle = WEBINPUTS=.:$(srcdir)/pdftexdir AM_V_P=$(AM_V_P) $(SHELL) ./tangle-sh $@ $(TANGLE) -pdftex_CPPFLAGS = $(pdftex_cppflags) $(am__append_149) +pdftex_CPPFLAGS = $(pdftex_cppflags) $(am__append_150) pdftex_CXXFLAGS = $(WARNING_CXXFLAGS) # With --enable-ipc, pdfTeX may need to link with -lsocket. @@ -4574,7 +4669,7 @@ pdftex_c_h = pdftexini.c pdftex0.c pdftexcoerce.h pdftexd.h nodist_pdftex_SOURCES = $(pdftex_c_h) pdftex-pool.c dist_pdftex_SOURCES = pdftexdir/pdftexextra.c pdftexdir/pdftexextra.h \ pdftexdir/pdftex_version.h pdftexdir/etex_version.h \ - $(am__append_150) + $(am__append_151) pdftex_ch_srcs = \ pdftexdir/pdftex.web \ pdftexdir/tex.ch0 \ @@ -5248,18 +5343,18 @@ libxetex = libxetex.a xetex_cppflags = $(AM_CPPFLAGS) -I$(srcdir)/xetexdir $(ICU_INCLUDES) \ $(FREETYPE2_INCLUDES) $(TECKIT_INCLUDES) $(HARFBUZZ_INCLUDES) \ $(GRAPHITE2_INCLUDES) $(LIBPNG_INCLUDES) $(ZLIB_INCLUDES) \ - $(PPLIB_INCLUDES) -I$(srcdir)/libmd5 $(am__append_109) \ - $(am__append_111) + $(PPLIB_INCLUDES) -I$(srcdir)/libmd5 $(am__append_110) \ + $(am__append_112) xetex_ldadd = $(libxetex) $(HARFBUZZ_LIBS) $(GRAPHITE2_LIBS) \ $(ICU_LIBS) $(ICU_LIBS_EXTRA) $(TECKIT_LIBS) $(LIBPNG_LIBS) \ $(FREETYPE2_LIBS) $(PPLIB_LIBS) $(ZLIB_LIBS) libmd5.a \ - $(am__append_112) + $(am__append_113) xetex_dependencies = $(proglib) $(KPATHSEA_DEPEND) $(ICU_DEPEND) \ $(TECKIT_DEPEND) $(HARFBUZZ_DEPEND) $(GRAPHITE2_DEPEND) \ $(LIBPNG_DEPEND) $(FREETYPE2_DEPEND) $(ZLIB_DEPEND) \ $(PPLIB_DEPEND) libmd5.a @XETEX_MACOSX_TRUE@xetex_LDFLAGS = -framework ApplicationServices -framework Cocoa -xetex_CPPFLAGS = $(xetex_cppflags) $(am__append_151) +xetex_CPPFLAGS = $(xetex_cppflags) $(am__append_152) xetex_CFLAGS = $(WARNING_CFLAGS) xetex_CXXFLAGS = # $(WARNING_CXXFLAGS) xetex_LDADD = $(xetex_ldadd) $(LDADD) $(ipc_socketlibs) @@ -5268,7 +5363,7 @@ xetex_c_h = xetexini.c xetex0.c xetexcoerce.h xetexd.h nodist_xetex_SOURCES = $(xetex_c_h) xetex-pool.c dist_xetex_SOURCES = xetexdir/xetexextra.c xetexdir/xetexextra.h \ xetexdir/etex_version.h xetexdir/xetex_version.h \ - $(am__append_152) + $(am__append_153) xetex_ch_srcs = \ xetexdir/xetex.web \ xetexdir/tex.ch0 \ @@ -5299,7 +5394,7 @@ libxetex_a_SOURCES = xetexdir/XeTeXFontInst.cpp \ xetexdir/image/jpegimage.h xetexdir/image/mfileio.c \ xetexdir/image/mfileio.h xetexdir/image/numbers.c \ xetexdir/image/numbers.h xetexdir/image/pngimage.c \ - xetexdir/image/pngimage.h $(am__append_113) $(am__append_114) + xetexdir/image/pngimage.h $(am__append_114) $(am__append_115) # We must create xetexd.h etc. before building the libxetex_a_OBJECTS. libxetex_prereq = xetexd.h $(xetex_dependencies) @@ -5404,12 +5499,12 @@ synctex_SOURCES = \ synctexdir/synctex_main.c synctex_CPPFLAGS = -I$(srcdir)/synctexdir -synctex_LDADD = $(libsynctex) $(ZLIB_LIBS) $(am__append_123) +synctex_LDADD = $(libsynctex) $(ZLIB_LIBS) $(am__append_124) libsynctex = $(LTLIBSYNCTEX) $(LIBSYNCTEX) libsynctex_la_CPPFLAGS = -I$(srcdir)/synctexdir $(ZLIB_INCLUDES) -DSYNCTEX_USE_LOCAL_HEADER libsynctex_a_CPPFLAGS = $(libsynctex_la_CPPFLAGS) libsynctex_la_LDFLAGS = -rpath @libdir@ -bindir @bindir@ -no-undefined -version-info $(SYNCTEX_LT_VERSINFO) -libsynctex_la_LIBADD = $(ZLIB_LIBS) $(am__append_124) +libsynctex_la_LIBADD = $(ZLIB_LIBS) $(am__append_125) libsynctex_la_SOURCES = \ synctexdir/synctex_parser.c \ synctexdir/synctex_parser_local.h \ @@ -5523,10 +5618,10 @@ all: ff-config.h $(MAKE) $(AM_MAKEFLAGS) all-recursive .SUFFIXES: -.SUFFIXES: .c .cc .cin .cpp .cxx .h .hin .lo .log .mm .o .obj .p .pin .pl .pl$(EXEEXT) .test .test$(EXEEXT) .trs +.SUFFIXES: .c .cc .cin .cpp .cxx .h .hin .l .lo .log .mm .o .obj .p .pin .pl .pl$(EXEEXT) .test .test$(EXEEXT) .trs .y am--refresh: Makefile @: -$(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am $(srcdir)/../../am/dist_hook.am $(srcdir)/am/bootstrap.am $(srcdir)/am/web.am $(srcdir)/am/cweb.am $(srcdir)/am/texmf.am $(srcdir)/mfluadir/am/mflua.am $(srcdir)/mfluadir/am/mfluaotfcc.am $(srcdir)/mfluajitdir/am/mfluajit.am $(srcdir)/mplibdir/am/mplib.am $(srcdir)/pmpostdir/am/pmpost.am $(srcdir)/mplibdir/am/libmputil.am $(srcdir)/mplibdir/am/libmplib.am $(srcdir)/etexdir/am/etex.am $(srcdir)/ptexdir/am/ptex.am $(srcdir)/eptexdir/am/eptex.am $(srcdir)/uptexdir/am/uptex.am $(srcdir)/euptexdir/am/euptex.am $(srcdir)/pdftexdir/am/libpdftex.am $(srcdir)/pdftexdir/am/pdftex.am $(srcdir)/pdftexdir/am/ttf2afm.am $(srcdir)/pdftexdir/am/pdftosrc.am $(srcdir)/luatexdir/am/luasocket.am $(srcdir)/luatexdir/am/luamisc.am $(srcdir)/luatexdir/am/libunilib.am $(srcdir)/luatexdir/am/luafontforge.am $(srcdir)/luatexdir/am/libluatex.am $(srcdir)/luatexdir/am/luaffi.am $(srcdir)/luatexdir/am/luatex.am $(srcdir)/luatexdir/am/luaharfbuzz.am $(srcdir)/xetexdir/am/xetex.am $(srcdir)/omegaware/am/omegaware.am $(srcdir)/alephdir/am/aleph.am $(srcdir)/synctexdir/am/synctex.am $(srcdir)/libmd5/am/md5.am $(srcdir)/../../am/bin_links.am $(am__configure_deps) +$(srcdir)/Makefile.in: @MAINTAINER_MODE_TRUE@ $(srcdir)/Makefile.am $(srcdir)/../../am/dist_hook.am $(srcdir)/am/bootstrap.am $(srcdir)/am/web.am $(srcdir)/am/cweb.am $(srcdir)/am/texmf.am $(srcdir)/mfluadir/am/mflua.am $(srcdir)/mfluadir/am/mfluaotfcc.am $(srcdir)/mfluajitdir/am/mfluajit.am $(srcdir)/mplibdir/am/mplib.am $(srcdir)/pmpostdir/am/pmpost.am $(srcdir)/mplibdir/am/libmputil.am $(srcdir)/mplibdir/am/libmplib.am $(srcdir)/etexdir/am/etex.am $(srcdir)/ptexdir/am/ptex.am $(srcdir)/eptexdir/am/eptex.am $(srcdir)/uptexdir/am/uptex.am $(srcdir)/euptexdir/am/euptex.am $(srcdir)/hitexdir/am/hitex.am $(srcdir)/pdftexdir/am/libpdftex.am $(srcdir)/pdftexdir/am/pdftex.am $(srcdir)/pdftexdir/am/ttf2afm.am $(srcdir)/pdftexdir/am/pdftosrc.am $(srcdir)/luatexdir/am/luasocket.am $(srcdir)/luatexdir/am/luamisc.am $(srcdir)/luatexdir/am/libunilib.am $(srcdir)/luatexdir/am/luafontforge.am $(srcdir)/luatexdir/am/libluatex.am $(srcdir)/luatexdir/am/luaffi.am $(srcdir)/luatexdir/am/luatex.am $(srcdir)/luatexdir/am/luaharfbuzz.am $(srcdir)/xetexdir/am/xetex.am $(srcdir)/omegaware/am/omegaware.am $(srcdir)/alephdir/am/aleph.am $(srcdir)/synctexdir/am/synctex.am $(srcdir)/libmd5/am/md5.am $(srcdir)/../../am/bin_links.am $(am__configure_deps) @for dep in $?; do \ case '$(am__configure_deps)' in \ *$$dep*) \ @@ -5548,7 +5643,7 @@ Makefile: $(srcdir)/Makefile.in $(top_builddir)/config.status echo ' cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles)'; \ cd $(top_builddir) && $(SHELL) ./config.status $@ $(am__maybe_remake_depfiles);; \ esac; -$(srcdir)/../../am/dist_hook.am $(srcdir)/am/bootstrap.am $(srcdir)/am/web.am $(srcdir)/am/cweb.am $(srcdir)/am/texmf.am $(srcdir)/mfluadir/am/mflua.am $(srcdir)/mfluadir/am/mfluaotfcc.am $(srcdir)/mfluajitdir/am/mfluajit.am $(srcdir)/mplibdir/am/mplib.am $(srcdir)/pmpostdir/am/pmpost.am $(srcdir)/mplibdir/am/libmputil.am $(srcdir)/mplibdir/am/libmplib.am $(srcdir)/etexdir/am/etex.am $(srcdir)/ptexdir/am/ptex.am $(srcdir)/eptexdir/am/eptex.am $(srcdir)/uptexdir/am/uptex.am $(srcdir)/euptexdir/am/euptex.am $(srcdir)/pdftexdir/am/libpdftex.am $(srcdir)/pdftexdir/am/pdftex.am $(srcdir)/pdftexdir/am/ttf2afm.am $(srcdir)/pdftexdir/am/pdftosrc.am $(srcdir)/luatexdir/am/luasocket.am $(srcdir)/luatexdir/am/luamisc.am $(srcdir)/luatexdir/am/libunilib.am $(srcdir)/luatexdir/am/luafontforge.am $(srcdir)/luatexdir/am/libluatex.am $(srcdir)/luatexdir/am/luaffi.am $(srcdir)/luatexdir/am/luatex.am $(srcdir)/luatexdir/am/luaharfbuzz.am $(srcdir)/xetexdir/am/xetex.am $(srcdir)/omegaware/am/omegaware.am $(srcdir)/alephdir/am/aleph.am $(srcdir)/synctexdir/am/synctex.am $(srcdir)/libmd5/am/md5.am $(srcdir)/../../am/bin_links.am $(am__empty): +$(srcdir)/../../am/dist_hook.am $(srcdir)/am/bootstrap.am $(srcdir)/am/web.am $(srcdir)/am/cweb.am $(srcdir)/am/texmf.am $(srcdir)/mfluadir/am/mflua.am $(srcdir)/mfluadir/am/mfluaotfcc.am $(srcdir)/mfluajitdir/am/mfluajit.am $(srcdir)/mplibdir/am/mplib.am $(srcdir)/pmpostdir/am/pmpost.am $(srcdir)/mplibdir/am/libmputil.am $(srcdir)/mplibdir/am/libmplib.am $(srcdir)/etexdir/am/etex.am $(srcdir)/ptexdir/am/ptex.am $(srcdir)/eptexdir/am/eptex.am $(srcdir)/uptexdir/am/uptex.am $(srcdir)/euptexdir/am/euptex.am $(srcdir)/hitexdir/am/hitex.am $(srcdir)/pdftexdir/am/libpdftex.am $(srcdir)/pdftexdir/am/pdftex.am $(srcdir)/pdftexdir/am/ttf2afm.am $(srcdir)/pdftexdir/am/pdftosrc.am $(srcdir)/luatexdir/am/luasocket.am $(srcdir)/luatexdir/am/luamisc.am $(srcdir)/luatexdir/am/libunilib.am $(srcdir)/luatexdir/am/luafontforge.am $(srcdir)/luatexdir/am/libluatex.am $(srcdir)/luatexdir/am/luaffi.am $(srcdir)/luatexdir/am/luatex.am $(srcdir)/luatexdir/am/luaharfbuzz.am $(srcdir)/xetexdir/am/xetex.am $(srcdir)/omegaware/am/omegaware.am $(srcdir)/alephdir/am/aleph.am $(srcdir)/synctexdir/am/synctex.am $(srcdir)/libmd5/am/md5.am $(srcdir)/../../am/bin_links.am $(am__empty): $(top_builddir)/config.status: $(top_srcdir)/configure $(CONFIG_STATUS_DEPENDENCIES) $(SHELL) ./config.status --recheck @@ -7950,6 +8045,21 @@ gftopk$(EXEEXT): $(gftopk_OBJECTS) $(gftopk_DEPENDENCIES) $(EXTRA_gftopk_DEPENDE gftype$(EXEEXT): $(gftype_OBJECTS) $(gftype_DEPENDENCIES) $(EXTRA_gftype_DEPENDENCIES) @rm -f gftype$(EXEEXT) $(AM_V_CCLD)$(LINK) $(gftype_OBJECTS) $(gftype_LDADD) $(LIBS) +shrink-parser.h: shrink-parser.c + @if test ! -f $@; then rm -f shrink-parser.c; else :; fi + @if test ! -f $@; then $(MAKE) $(AM_MAKEFLAGS) shrink-parser.c; else :; fi + +hishrink$(EXEEXT): $(hishrink_OBJECTS) $(hishrink_DEPENDENCIES) $(EXTRA_hishrink_DEPENDENCIES) + @rm -f hishrink$(EXEEXT) + $(AM_V_CCLD)$(LINK) $(hishrink_OBJECTS) $(hishrink_LDADD) $(LIBS) + +histretch$(EXEEXT): $(histretch_OBJECTS) $(histretch_DEPENDENCIES) $(EXTRA_histretch_DEPENDENCIES) + @rm -f histretch$(EXEEXT) + $(AM_V_CCLD)$(LINK) $(histretch_OBJECTS) $(histretch_LDADD) $(LIBS) + +hitex$(EXEEXT): $(hitex_OBJECTS) $(hitex_DEPENDENCIES) $(EXTRA_hitex_DEPENDENCIES) + @rm -f hitex$(EXEEXT) + $(AM_V_CCLD)$(LINK) $(hitex_OBJECTS) $(hitex_LDADD) $(LIBS) initex$(EXEEXT): $(initex_OBJECTS) $(initex_DEPENDENCIES) $(EXTRA_initex_DEPENDENCIES) @rm -f initex$(EXEEXT) @@ -8331,6 +8441,16 @@ distclean-compile: @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gftodvi.Po@am__quote@ # am--include-marker @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gftopk.Po@am__quote@ # am--include-marker @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gftype.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hishrink-hformat.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hishrink-hishrink.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hishrink-shrink-lexer.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hishrink-shrink-parser.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/histretch-hformat.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/histretch-histretch.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hitex-hformat.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hitex-hitex.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hitex-hput.Po@am__quote@ # am--include-marker +@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/hitex-htex.Po@am__quote@ # am--include-marker @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/initex-callexe.Po@am__quote@ # am--include-marker @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libluahbtexspecific_a-luainit-hb.Po@am__quote@ # am--include-marker @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/libluahbtexspecific_a-luastuff-hb.Po@am__quote@ # am--include-marker @@ -17248,6 +17368,146 @@ euptex-euptex-pool.obj: euptex-pool.c @AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ @am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(euptex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o euptex-euptex-pool.obj `if test -f 'euptex-pool.c'; then $(CYGPATH_W) 'euptex-pool.c'; else $(CYGPATH_W) '$(srcdir)/euptex-pool.c'; fi` +hishrink-hformat.o: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-hformat.o -MD -MP -MF $(DEPDIR)/hishrink-hformat.Tpo -c -o hishrink-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-hformat.Tpo $(DEPDIR)/hishrink-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='hishrink-hformat.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c + +hishrink-hformat.obj: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-hformat.obj -MD -MP -MF $(DEPDIR)/hishrink-hformat.Tpo -c -o hishrink-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-hformat.Tpo $(DEPDIR)/hishrink-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='hishrink-hformat.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` + +hishrink-hishrink.o: hishrink.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-hishrink.o -MD -MP -MF $(DEPDIR)/hishrink-hishrink.Tpo -c -o hishrink-hishrink.o `test -f 'hishrink.c' || echo '$(srcdir)/'`hishrink.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-hishrink.Tpo $(DEPDIR)/hishrink-hishrink.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hishrink.c' object='hishrink-hishrink.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-hishrink.o `test -f 'hishrink.c' || echo '$(srcdir)/'`hishrink.c + +hishrink-hishrink.obj: hishrink.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-hishrink.obj -MD -MP -MF $(DEPDIR)/hishrink-hishrink.Tpo -c -o hishrink-hishrink.obj `if test -f 'hishrink.c'; then $(CYGPATH_W) 'hishrink.c'; else $(CYGPATH_W) '$(srcdir)/hishrink.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-hishrink.Tpo $(DEPDIR)/hishrink-hishrink.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hishrink.c' object='hishrink-hishrink.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-hishrink.obj `if test -f 'hishrink.c'; then $(CYGPATH_W) 'hishrink.c'; else $(CYGPATH_W) '$(srcdir)/hishrink.c'; fi` + +hishrink-shrink-lexer.o: shrink-lexer.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-shrink-lexer.o -MD -MP -MF $(DEPDIR)/hishrink-shrink-lexer.Tpo -c -o hishrink-shrink-lexer.o `test -f 'shrink-lexer.c' || echo '$(srcdir)/'`shrink-lexer.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-shrink-lexer.Tpo $(DEPDIR)/hishrink-shrink-lexer.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='shrink-lexer.c' object='hishrink-shrink-lexer.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-shrink-lexer.o `test -f 'shrink-lexer.c' || echo '$(srcdir)/'`shrink-lexer.c + +hishrink-shrink-lexer.obj: shrink-lexer.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-shrink-lexer.obj -MD -MP -MF $(DEPDIR)/hishrink-shrink-lexer.Tpo -c -o hishrink-shrink-lexer.obj `if test -f 'shrink-lexer.c'; then $(CYGPATH_W) 'shrink-lexer.c'; else $(CYGPATH_W) '$(srcdir)/shrink-lexer.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-shrink-lexer.Tpo $(DEPDIR)/hishrink-shrink-lexer.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='shrink-lexer.c' object='hishrink-shrink-lexer.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-shrink-lexer.obj `if test -f 'shrink-lexer.c'; then $(CYGPATH_W) 'shrink-lexer.c'; else $(CYGPATH_W) '$(srcdir)/shrink-lexer.c'; fi` + +hishrink-shrink-parser.o: shrink-parser.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-shrink-parser.o -MD -MP -MF $(DEPDIR)/hishrink-shrink-parser.Tpo -c -o hishrink-shrink-parser.o `test -f 'shrink-parser.c' || echo '$(srcdir)/'`shrink-parser.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-shrink-parser.Tpo $(DEPDIR)/hishrink-shrink-parser.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='shrink-parser.c' object='hishrink-shrink-parser.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-shrink-parser.o `test -f 'shrink-parser.c' || echo '$(srcdir)/'`shrink-parser.c + +hishrink-shrink-parser.obj: shrink-parser.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hishrink-shrink-parser.obj -MD -MP -MF $(DEPDIR)/hishrink-shrink-parser.Tpo -c -o hishrink-shrink-parser.obj `if test -f 'shrink-parser.c'; then $(CYGPATH_W) 'shrink-parser.c'; else $(CYGPATH_W) '$(srcdir)/shrink-parser.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hishrink-shrink-parser.Tpo $(DEPDIR)/hishrink-shrink-parser.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='shrink-parser.c' object='hishrink-shrink-parser.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hishrink_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hishrink-shrink-parser.obj `if test -f 'shrink-parser.c'; then $(CYGPATH_W) 'shrink-parser.c'; else $(CYGPATH_W) '$(srcdir)/shrink-parser.c'; fi` + +histretch-hformat.o: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT histretch-hformat.o -MD -MP -MF $(DEPDIR)/histretch-hformat.Tpo -c -o histretch-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/histretch-hformat.Tpo $(DEPDIR)/histretch-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='histretch-hformat.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o histretch-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c + +histretch-hformat.obj: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT histretch-hformat.obj -MD -MP -MF $(DEPDIR)/histretch-hformat.Tpo -c -o histretch-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/histretch-hformat.Tpo $(DEPDIR)/histretch-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='histretch-hformat.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o histretch-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` + +histretch-histretch.o: histretch.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT histretch-histretch.o -MD -MP -MF $(DEPDIR)/histretch-histretch.Tpo -c -o histretch-histretch.o `test -f 'histretch.c' || echo '$(srcdir)/'`histretch.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/histretch-histretch.Tpo $(DEPDIR)/histretch-histretch.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='histretch.c' object='histretch-histretch.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o histretch-histretch.o `test -f 'histretch.c' || echo '$(srcdir)/'`histretch.c + +histretch-histretch.obj: histretch.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT histretch-histretch.obj -MD -MP -MF $(DEPDIR)/histretch-histretch.Tpo -c -o histretch-histretch.obj `if test -f 'histretch.c'; then $(CYGPATH_W) 'histretch.c'; else $(CYGPATH_W) '$(srcdir)/histretch.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/histretch-histretch.Tpo $(DEPDIR)/histretch-histretch.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='histretch.c' object='histretch-histretch.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(histretch_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o histretch-histretch.obj `if test -f 'histretch.c'; then $(CYGPATH_W) 'histretch.c'; else $(CYGPATH_W) '$(srcdir)/histretch.c'; fi` + +hitex-hformat.o: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hformat.o -MD -MP -MF $(DEPDIR)/hitex-hformat.Tpo -c -o hitex-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hformat.Tpo $(DEPDIR)/hitex-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='hitex-hformat.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hformat.o `test -f 'hformat.c' || echo '$(srcdir)/'`hformat.c + +hitex-hformat.obj: hformat.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hformat.obj -MD -MP -MF $(DEPDIR)/hitex-hformat.Tpo -c -o hitex-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hformat.Tpo $(DEPDIR)/hitex-hformat.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hformat.c' object='hitex-hformat.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hformat.obj `if test -f 'hformat.c'; then $(CYGPATH_W) 'hformat.c'; else $(CYGPATH_W) '$(srcdir)/hformat.c'; fi` + +hitex-hput.o: hput.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hput.o -MD -MP -MF $(DEPDIR)/hitex-hput.Tpo -c -o hitex-hput.o `test -f 'hput.c' || echo '$(srcdir)/'`hput.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hput.Tpo $(DEPDIR)/hitex-hput.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hput.c' object='hitex-hput.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hput.o `test -f 'hput.c' || echo '$(srcdir)/'`hput.c + +hitex-hput.obj: hput.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hput.obj -MD -MP -MF $(DEPDIR)/hitex-hput.Tpo -c -o hitex-hput.obj `if test -f 'hput.c'; then $(CYGPATH_W) 'hput.c'; else $(CYGPATH_W) '$(srcdir)/hput.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hput.Tpo $(DEPDIR)/hitex-hput.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hput.c' object='hitex-hput.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hput.obj `if test -f 'hput.c'; then $(CYGPATH_W) 'hput.c'; else $(CYGPATH_W) '$(srcdir)/hput.c'; fi` + +hitex-htex.o: htex.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-htex.o -MD -MP -MF $(DEPDIR)/hitex-htex.Tpo -c -o hitex-htex.o `test -f 'htex.c' || echo '$(srcdir)/'`htex.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-htex.Tpo $(DEPDIR)/hitex-htex.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='htex.c' object='hitex-htex.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-htex.o `test -f 'htex.c' || echo '$(srcdir)/'`htex.c + +hitex-htex.obj: htex.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-htex.obj -MD -MP -MF $(DEPDIR)/hitex-htex.Tpo -c -o hitex-htex.obj `if test -f 'htex.c'; then $(CYGPATH_W) 'htex.c'; else $(CYGPATH_W) '$(srcdir)/htex.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-htex.Tpo $(DEPDIR)/hitex-htex.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='htex.c' object='hitex-htex.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-htex.obj `if test -f 'htex.c'; then $(CYGPATH_W) 'htex.c'; else $(CYGPATH_W) '$(srcdir)/htex.c'; fi` + +hitex-hitex.o: hitex.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hitex.o -MD -MP -MF $(DEPDIR)/hitex-hitex.Tpo -c -o hitex-hitex.o `test -f 'hitex.c' || echo '$(srcdir)/'`hitex.c +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hitex.Tpo $(DEPDIR)/hitex-hitex.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hitex.c' object='hitex-hitex.o' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hitex.o `test -f 'hitex.c' || echo '$(srcdir)/'`hitex.c + +hitex-hitex.obj: hitex.c +@am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT hitex-hitex.obj -MD -MP -MF $(DEPDIR)/hitex-hitex.Tpo -c -o hitex-hitex.obj `if test -f 'hitex.c'; then $(CYGPATH_W) 'hitex.c'; else $(CYGPATH_W) '$(srcdir)/hitex.c'; fi` +@am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/hitex-hitex.Tpo $(DEPDIR)/hitex-hitex.Po +@AMDEP_TRUE@@am__fastdepCC_FALSE@ $(AM_V_CC)source='hitex.c' object='hitex-hitex.obj' libtool=no @AMDEPBACKSLASH@ +@AMDEP_TRUE@@am__fastdepCC_FALSE@ DEPDIR=$(DEPDIR) $(CCDEPMODE) $(depcomp) @AMDEPBACKSLASH@ +@am__fastdepCC_FALSE@ $(AM_V_CC@am__nodep@)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(hitex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -c -o hitex-hitex.obj `if test -f 'hitex.c'; then $(CYGPATH_W) 'hitex.c'; else $(CYGPATH_W) '$(srcdir)/hitex.c'; fi` + initex-callexe.o: callexe.c @am__fastdepCC_TRUE@ $(AM_V_CC)$(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(initex_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -MT initex-callexe.o -MD -MP -MF $(DEPDIR)/initex-callexe.Tpo -c -o initex-callexe.o `test -f 'callexe.c' || echo '$(srcdir)/'`callexe.c @am__fastdepCC_TRUE@ $(AM_V_at)$(am__mv) $(DEPDIR)/initex-callexe.Tpo $(DEPDIR)/initex-callexe.Po @@ -18636,6 +18896,13 @@ xetex-dummy.obj: dummy.cxx @AMDEP_TRUE@@am__fastdepCXX_FALSE@ DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@ @am__fastdepCXX_FALSE@ $(AM_V_CXX@am__nodep@)$(LTCXXCOMPILE) -c -o $@ $< +.l.c: + $(AM_V_LEX)$(am__skiplex) $(SHELL) $(YLWRAP) $< $(LEX_OUTPUT_ROOT).c $@ -- $(LEXCOMPILE) + +shrink-lexer.c: shrink-lexer.l + $(AM_V_LEX) \ + $(SHELL) $(YLWRAP) `test -f 'shrink-lexer.l' || echo '$(srcdir)/'`shrink-lexer.l $(LEX_OUTPUT_ROOT).c shrink-lexer.c -- $(LEX) $(AM_LFLAGS) $(LFLAGS) + .mm.o: @am__fastdepOBJCXX_TRUE@ $(AM_V_OBJCXX)depbase=`echo $@ | sed 's|[^/]*$$|$(DEPDIR)/&|;s|\.o$$||'`;\ @am__fastdepOBJCXX_TRUE@ $(OBJCXXCOMPILE) -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ $< &&\ @@ -18674,6 +18941,13 @@ xetexdir/libxetex_a-XeTeXFontMgr_Mac.obj: xetexdir/XeTeXFontMgr_Mac.mm @AMDEP_TRUE@@am__fastdepOBJCXX_FALSE@ DEPDIR=$(DEPDIR) $(OBJCXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@ @am__fastdepOBJCXX_FALSE@ $(AM_V_OBJCXX@am__nodep@)$(OBJCXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(libxetex_a_CPPFLAGS) $(CPPFLAGS) $(libxetex_a_OBJCXXFLAGS) $(OBJCXXFLAGS) -c -o xetexdir/libxetex_a-XeTeXFontMgr_Mac.obj `if test -f 'xetexdir/XeTeXFontMgr_Mac.mm'; then $(CYGPATH_W) 'xetexdir/XeTeXFontMgr_Mac.mm'; else $(CYGPATH_W) '$(srcdir)/xetexdir/XeTeXFontMgr_Mac.mm'; fi` +.y.c: + $(AM_V_YACC)$(am__skipyacc) $(SHELL) $(YLWRAP) $< y.tab.c $@ y.tab.h `echo $@ | $(am__yacc_c2h)` y.output $*.output -- $(YACCCOMPILE) + +shrink-parser.c: shrink-parser.y + $(AM_V_YACC) \ + $(SHELL) $(YLWRAP) `test -f 'shrink-parser.y' || echo '$(srcdir)/'`shrink-parser.y y.tab.c shrink-parser.c y.tab.h `echo shrink-parser.c | $(am__yacc_c2h)` y.output shrink-parser.output -- $(YACC) $(AM_YFLAGS) $(YFLAGS) + mostlyclean-libtool: -rm -f *.lo @@ -19324,6 +19598,9 @@ mostlyclean-generic: -test -z "$(TEST_SUITE_LOG)" || rm -f $(TEST_SUITE_LOG) clean-generic: + -rm -f shrink-lexer.c + -rm -f shrink-parser.c + -rm -f shrink-parser.h -test -z "$(CLEANFILES)" || rm -f $(CLEANFILES) distclean-generic: @@ -19511,6 +19788,16 @@ distclean: distclean-recursive -rm -f ./$(DEPDIR)/gftodvi.Po -rm -f ./$(DEPDIR)/gftopk.Po -rm -f ./$(DEPDIR)/gftype.Po + -rm -f ./$(DEPDIR)/hishrink-hformat.Po + -rm -f ./$(DEPDIR)/hishrink-hishrink.Po + -rm -f ./$(DEPDIR)/hishrink-shrink-lexer.Po + -rm -f ./$(DEPDIR)/hishrink-shrink-parser.Po + -rm -f ./$(DEPDIR)/histretch-hformat.Po + -rm -f ./$(DEPDIR)/histretch-histretch.Po + -rm -f ./$(DEPDIR)/hitex-hformat.Po + -rm -f ./$(DEPDIR)/hitex-hitex.Po + -rm -f ./$(DEPDIR)/hitex-hput.Po + -rm -f ./$(DEPDIR)/hitex-htex.Po -rm -f ./$(DEPDIR)/initex-callexe.Po -rm -f ./$(DEPDIR)/libluahbtexspecific_a-luainit-hb.Po -rm -f ./$(DEPDIR)/libluahbtexspecific_a-luastuff-hb.Po @@ -20280,6 +20567,16 @@ maintainer-clean: maintainer-clean-recursive -rm -f ./$(DEPDIR)/gftodvi.Po -rm -f ./$(DEPDIR)/gftopk.Po -rm -f ./$(DEPDIR)/gftype.Po + -rm -f ./$(DEPDIR)/hishrink-hformat.Po + -rm -f ./$(DEPDIR)/hishrink-hishrink.Po + -rm -f ./$(DEPDIR)/hishrink-shrink-lexer.Po + -rm -f ./$(DEPDIR)/hishrink-shrink-parser.Po + -rm -f ./$(DEPDIR)/histretch-hformat.Po + -rm -f ./$(DEPDIR)/histretch-histretch.Po + -rm -f ./$(DEPDIR)/hitex-hformat.Po + -rm -f ./$(DEPDIR)/hitex-hitex.Po + -rm -f ./$(DEPDIR)/hitex-hput.Po + -rm -f ./$(DEPDIR)/hitex-htex.Po -rm -f ./$(DEPDIR)/initex-callexe.Po -rm -f ./$(DEPDIR)/libluahbtexspecific_a-luainit-hb.Po -rm -f ./$(DEPDIR)/libluahbtexspecific_a-luastuff-hb.Po @@ -21825,6 +22122,48 @@ euptrip.diffs: euptex$(EXEEXT) dvitype$(EXEEXT) pltotf$(EXEEXT) tftopl$(EXEEXT) euptrip-clean: rm -rf euptripdir +$(format_c_h_l_y): format-tangle + $(hi_ctangle_sh) format +# +format-tangle: ctangle$(EXEEXT) hitexdir/format.w tangle-sh + $(hi_ctangle_sh) format + +$(hitex_c_h): hitex-tangle + $(hi_ctangle_sh) hitex +# +hitex-tangle: ctangle$(EXEEXT) hitexdir/hitex.w tangle-sh + $(hi_ctangle_sh) hitex + +# htex.c needs hitex.h, so depend on the hitex tangle. +$(htex_c_h): htex-tangle hitex-tangle + $(hi_ctangle_sh) htex +# +htex-tangle: ctangle$(EXEEXT) hitexdir/htex.w tangle-sh hitex-tangle + $(hi_ctangle_sh) htex + +# Generating hformat.c using mkhformat. +hformat.c: mkhformat + ./mkhformat >hformat.c || { rm -f hformat.c; exit 1; } + +# Postprocessing lex and yacc files generated by ctangle. +# (SED is defined with AC_PROG_SED) +shrink-parser.y: $(srcdir)/hitexdir/yacc.sed shrink.yacc-in + $(SED) -f $(srcdir)/hitexdir/yacc.sed shrink.yacc-in >shrink-parser.y \ + || { rm -f shrink-parser.y; exit 1; } +# +shrink-lexer.l: $(srcdir)/hitexdir/lex.sed shrink.lex-in + $(SED) -f $(srcdir)/hitexdir/lex.sed shrink.lex-in >shrink-lexer.l \ + || { rm -f shrink-lexer.l; exit 1; } + +# shrink needs the yacc header. It's actually the .o that should be the +# target here, seems to me, but hishrink.o is not used for the object +# name, it's hishrink-hishrink.o (because the program is also named +# hishrink), and adding that here ends up trying to link with +# hishrink-hishrink.o (I don't know), which doesn't exist. Sigh. +hishrink.c: shrink-parser.h shrink-parser.c + +# still missing + # We must create pdftexd.h (and xpdf...) before building the libpdftex_a_OBJECTS. $(libpdftex_a_OBJECTS): pdftexd.h $(XPDF_DEPEND) $(ZLIB_DEPEND) $(LIBPNG_DEPEND) $(pdftex_OBJECTS): $(pdftex_prereq) diff --git a/Build/source/texk/web2c/ac/web2c.ac b/Build/source/texk/web2c/ac/web2c.ac index 40afc44f3d6..aec20a703c5 100644 --- a/Build/source/texk/web2c/ac/web2c.ac +++ b/Build/source/texk/web2c/ac/web2c.ac @@ -1,7 +1,7 @@ dnl $Id$ # texk/web2c/ac/web2c.ac: configure.ac fragment for TL subdir dnl -dnl Copyright 2015-2020 Karl Berry <tex-live@tug.org> +dnl Copyright 2015-2021 Karl Berry <tex-live@tug.org> dnl Copyright 2009-2015 Peter Breitenlohner <tex-live@tug.org> dnl You may freely use, modify and/or distribute this file. dnl @@ -36,6 +36,7 @@ m4_define([kpse_tex_progs], [dnl [[uptex], [yes], [yes], [upTeX], [ptexenc zlib]], [[euptex], [yes], [yes], [e-upTeX], [ptexenc zlib]], [[aleph], [yes], [], [Aleph], []], +[[hitex], [no], [], [HiTeX], [zlib]], [[pdftex], [yes], [yes], [pdfTeX], [xpdf libpng zlib]], [[luatex], [yes], [], [LuaTeX], [pplib libpng zziplib lua53]], [[luajittex], [yes], [], [LuaJITTeX], [pplib libpng zziplib luajit]], diff --git a/Build/source/texk/web2c/c-auto.in b/Build/source/texk/web2c/c-auto.in index 9b356d00a32..7ffd2216b29 100644 --- a/Build/source/texk/web2c/c-auto.in +++ b/Build/source/texk/web2c/c-auto.in @@ -2,7 +2,7 @@ /* w2c/c-auto.h: defines for web2c, as determined by configure. - Copyright 1994-97, 2008-2012 Karl Berry. + Copyright 1994-97, 2008-2021 Karl Berry. Copyright 1997-99, 2002, 2005 Olaf Weber. This program is free software: you can redistribute it and/or modify diff --git a/Build/source/texk/web2c/configure b/Build/source/texk/web2c/configure index 974706d41e0..185c8da41a4 100755 --- a/Build/source/texk/web2c/configure +++ b/Build/source/texk/web2c/configure @@ -822,6 +822,8 @@ PDFTEX_SYNCTEX_FALSE PDFTEX_SYNCTEX_TRUE PDFTEX_FALSE PDFTEX_TRUE +HITEX_FALSE +HITEX_TRUE ALEPH_FALSE ALEPH_TRUE EUPTEX_SYNCTEX_FALSE @@ -1045,6 +1047,7 @@ enable_uptex_synctex enable_euptex enable_euptex_synctex enable_aleph +enable_hitex enable_pdftex enable_pdftex_synctex enable_luatex @@ -1784,6 +1787,7 @@ Optional Features: --disable-euptex do not compile and install e-upTeX --disable-euptex-synctex build e-upTeX without SyncTeX support --disable-aleph do not compile and install Aleph + --enable-hitex compile and install HiTeX --disable-pdftex do not compile and install pdfTeX --disable-pdftex-synctex build pdfTeX without SyncTeX support --disable-luatex do not compile and install LuaTeX @@ -19811,6 +19815,21 @@ case $enable_aleph in #( *) : enable_aleph=yes ;; esac +# Check whether --enable-hitex was given. +if test ${enable_hitex+y} +then : + enableval=$enable_hitex; +fi +case $enable_hitex in #( + yes | no) : + ;; #( + *) : + enable_hitex=no ;; +esac + +test "x$enable_web2c:$enable_hitex" = xyes:yes && { + need_zlib=yes +} # Check whether --enable-pdftex was given. if test ${enable_pdftex+y} then : @@ -22526,6 +22545,13 @@ else ALEPH_TRUE='#' ALEPH_FALSE= fi + if test "x$enable_hitex" = xyes; then + HITEX_TRUE= + HITEX_FALSE='#' +else + HITEX_TRUE='#' + HITEX_FALSE= +fi if test "x$enable_pdftex" = xyes; then PDFTEX_TRUE= PDFTEX_FALSE='#' @@ -28375,6 +28401,10 @@ if test -z "${ALEPH_TRUE}" && test -z "${ALEPH_FALSE}"; then as_fn_error $? "conditional \"ALEPH\" was never defined. Usually this means the macro was only invoked conditionally." "$LINENO" 5 fi +if test -z "${HITEX_TRUE}" && test -z "${HITEX_FALSE}"; then + as_fn_error $? "conditional \"HITEX\" was never defined. +Usually this means the macro was only invoked conditionally." "$LINENO" 5 +fi if test -z "${PDFTEX_TRUE}" && test -z "${PDFTEX_FALSE}"; then as_fn_error $? "conditional \"PDFTEX\" was never defined. Usually this means the macro was only invoked conditionally." "$LINENO" 5 diff --git a/Build/source/texk/web2c/configure.ac b/Build/source/texk/web2c/configure.ac index f2ecd7f26ca..7b00fd4fadb 100644 --- a/Build/source/texk/web2c/configure.ac +++ b/Build/source/texk/web2c/configure.ac @@ -326,7 +326,7 @@ AC_CONFIG_HEADERS([w2c/c-auto.h:c-auto.in], AH_TOP([/* w2c/c-auto.h: defines for web2c, as determined by configure. - Copyright 1994-97, 2008-2012 Karl Berry. + Copyright 1994-97, 2008-2021 Karl Berry. Copyright 1997-99, 2002, 2005 Olaf Weber. This program is free software: you can redistribute it and/or modify diff --git a/Build/source/texk/web2c/hitexdir/am/hitex.am b/Build/source/texk/web2c/hitexdir/am/hitex.am new file mode 100644 index 00000000000..31cf845c487 --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/am/hitex.am @@ -0,0 +1,100 @@ +## $Id$ +## texk/web2c/hitexdir/am/hitex.am: Makefile fragment for HiTeX +## +## Copyright 2021 Martin Ruckert <ruckert@cs.hm.edu> +## You may freely use, modify and/or distribute this file. + +if HITEX +bin_PROGRAMS += hitex hishrink histretch +endif HITEX +EXTRA_PROGRAMS += hitex hishrink histretch + +#kb hitex_CFLAGS = $(AM_CFLAGS) \ +#kb -Wno-parentheses -Wno-maybe-uninitialized -Wno-unused-function -Wno-unused-variable +hitex_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +hitex_LDADD = $(KPATHSEA_LIBS) $(ZLIB_LIBS) +# +histretch_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +histretch_LDADD = $(ZLIB_LIBS) +# +hishrink_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_INCLUDES) +hishrink_LDADD = $(ZLIB_LIBS) + +# We want debugging for the parser, and we use features not in POSIX yacc. +# I guess the result is that we assume bison? Not sure if that's ok. +AM_YFLAGS = -d -v -Wno-yacc + +# HiTeX CWEB sources +hitex_web = hitexdir/format.w hitexdir/htex.w hitexdir/hitex.w + +# Creating several files: need stamp file and two rules with identical recipes +hi_ctangle_sh = CWEBINPUTS=$(srcdir)/hitexdir AM_V_P=$(AM_V_P) $(SHELL) ./tangle-sh $@ $(CTANGLE) + +# HiTeX C/yacc/lex sources generated using ctangle. +# For each cweb (.w) source file, list the files generated. +format_c_h_l_y = basetypes.h error.h hformat.h \ + mkhformat.c \ + hput.c hput.h \ + hget.c hget.h \ + shrink.lex-in shrink.yacc-in \ + hishrink.c histretch.c +htex_c_h = htex.c htex.h +hitex_c_h = hitex.c hitex.h + +$(format_c_h_l_y): format-tangle + $(hi_ctangle_sh) format +# +format-tangle: ctangle$(EXEEXT) hitexdir/format.w tangle-sh + $(hi_ctangle_sh) format + +$(hitex_c_h): hitex-tangle + $(hi_ctangle_sh) hitex +# +hitex-tangle: ctangle$(EXEEXT) hitexdir/hitex.w tangle-sh + $(hi_ctangle_sh) hitex + +# htex.c needs hitex.h, so depend on the hitex tangle. +$(htex_c_h): htex-tangle hitex-tangle + $(hi_ctangle_sh) htex +# +htex-tangle: ctangle$(EXEEXT) hitexdir/htex.w tangle-sh hitex-tangle + $(hi_ctangle_sh) htex + +# Generating hformat.c using mkhformat. +hformat.c: mkhformat + ./mkhformat >hformat.c || { rm -f hformat.c; exit 1; } + +# Postprocessing lex and yacc files generated by ctangle. +# (SED is defined with AC_PROG_SED) +shrink-parser.y: $(srcdir)/hitexdir/yacc.sed shrink.yacc-in + $(SED) -f $(srcdir)/hitexdir/yacc.sed shrink.yacc-in >shrink-parser.y \ + || { rm -f shrink-parser.y; exit 1; } +# +shrink-lexer.l: $(srcdir)/hitexdir/lex.sed shrink.lex-in + $(SED) -f $(srcdir)/hitexdir/lex.sed shrink.lex-in >shrink-lexer.l \ + || { rm -f shrink-lexer.l; exit 1; } + +# Other web2c/*dir/am/*.am engine Makefile fragments define a bunch of +# _OBJECTS variables. This does not seem right to me. Instead, we +# correctly define the _SOURCES. +# +nodist_hitex_SOURCES = hformat.c hput.c $(htex_c_h) $(hitex_c_h) +nodist_histretch_SOURCES = hformat.c histretch.c +nodist_hishrink_SOURCES = hformat.c hishrink.c shrink-lexer.l shrink-parser.y + +# shrink needs the yacc header. It's actually the .o that should be the +# target here, seems to me, but hishrink.o is not used for the object +# name, it's hishrink-hishrink.o (because the program is also named +# hishrink), and adding that here ends up trying to link with +# hishrink-hishrink.o (I don't know), which doesn't exist. Sigh. +hishrink.c: shrink-parser.h shrink-parser.c + +EXTRA_DIST += hitexdir/ChangeLog $(hitex_web) lex.sed yacc.sed + +DISTCLEANFILES += $(nodist_hitex_SOURCES) +DISTCLEANFILES += $(nodist_hishrink_SOURCES) $(nodist_histretch_SOURCES) +DISTCLEANFILES += format-tangle htex-tangle hitex-tangle +DISTCLEANFILES += shrink-parser.* shrink-lexer.* + +## HiTeX tests +# still missing diff --git a/Build/source/texk/web2c/hitexdir/format.w b/Build/source/texk/web2c/hitexdir/format.w new file mode 100644 index 00000000000..0aa8152ccaa --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/format.w @@ -0,0 +1,10509 @@ +% This file is part of HINT +% Copyright 2017-2021 Martin Ruckert +% +% Permission is hereby granted, free of charge, to any person obtaining a copy +% of this software and associated documentation files (the "Software"), to deal +% in the Software without restriction, including without limitation the rights +% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +% copies of the Software, and to permit persons to whom the Software is +% furnished to do so, subject to the following conditions: +% +% The above copyright notice and this permission notice shall be +% included in all copies or substantial portions of the Software. +% +% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +% COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, +% WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT +% OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +% THE SOFTWARE. +% +% Except as contained in this notice, the name of the copyright holders shall +% not be used in advertising or otherwise to promote the sale, use or other +% dealings in this Software without prior written authorization from the +% copyright holders. + +\input ../hint.sty + +%% defining how to display certain C identifiers + +@s int8_t int +@s uint8_t int +@s int16_t int +@s uint16_t int +@s uint32_t int +@s int32_t int +@s uint64_t int +@s bool int + +@ + +\makeindex +\maketoc +\makecode +%\makefigindex +\titletrue + + +\def\setrevision$#1: #2 ${\gdef\lastrevision{#2}} +\setrevision$Revision: 2485 $ +\def\setdate$#1(#2) ${\gdef\lastdate{#2}} +\setdate$Date: 2021-08-19 19:37:13 +0200 (Thu, 19 Aug 2021) $ + +\null + +\font\largetitlefont=cmssbx10 scaled\magstep4 +\font\Largetitlefont=cmssbx10 at 40pt +\font\hugetitlefont=cmssbx10 at 48pt +\font\smalltitlefontit=cmbxti10 scaled\magstep3 +\font\smalltitlefont=cmssbx10 scaled\magstep3 + +%halftitle +\def\raggedleft{\leftskip=0pt plus 5em\parfillskip=0pt +\spaceskip=.3333em \xspaceskip=0.5em \emergencystretch=1em\relax +\hyphenpenalty=1000\exhyphenpenalty=1000\pretolerance=10000\linepenalty=5000 +} +\hbox{} +\vskip 0pt plus 1fill +{ \baselineskip=60pt + \hugetitlefont\hfill HINT:\par + \Largetitlefont\raggedleft The File Format\par +} +\vskip 0pt plus 5fill +\eject +% verso of half title +\titletrue +\null +\vfill +\eject + +% title +\titletrue +\hbox{} +\vskip 0pt plus 1fill +{ + \baselineskip=1cm\parindent=0pt + {\largetitlefont\raggedright HINT: The File Format}\par + \leftline{\smalltitlefont Version 1.3} + \vskip 10pt plus 0.5fill + \leftline{\smalltitlefont Reflowable} + \vskip-3pt + \leftline{\smalltitlefont Output} + \vskip-3pt + \leftline{\smalltitlefont for \TeX} + \vskip 10pt plus 0.5fill + \hskip 0pt plus 2fill{\it F\"ur meine Mutter}\hskip 0pt plus 0.5fill\hbox{} + \bigskip + \vskip 10pt plus 3fill + \raggedright\baselineskip=12pt + {\bf MARTIN RUCKERT} \ {\it Munich University of Applied Sciences}\par + \bigskip + \leftline{Second edition} + \bigskip +% \leftline{\bf Eigendruck im Selbstverlag} +% \bigskip +} +\eject + +% verso of title +% copyright page (ii) +\titletrue +\begingroup +\figrm +\parindent=0pt +%\null +{\raggedright\advance\rightskip 3.5pc +The author has taken care in the preparation of this book, +but makes no expressed or implied warranty of any kind and assumes no +responsibility for errors or omissions. No liability is assumed for +incidental or consequential damages in connection with or arising out +of the use of the information or programs contained herein. + +\bigskip +{\figtt\obeylines\obeyspaces\baselineskip=11pt +Ruckert, Martin. + HINT: The File Format + Includes index. + ISBN 979-854992684-4 +} +\bigskip + +{\raggedright\advance\rightskip 3.5pc +\def\:{\discretionary{}{}{}} +Internet page {\tt http:\://hint.\:userweb.\:mwn.\:de/\:hint/\:format.html} +may contain current information about this book, downloadable software, +and news. + +\vfill +Copyright $\copyright$ 2019, 2021 by Martin Ruckert +\smallskip +All rights reserved. +Printed by Kindle Direct Publishing. +This publication is protected by copyright, and permission must be +obtained prior to any prohibited reproduction, storage in +a~retrieval system, or transmission in any form or by any means, electronic, +mechanical, photocopying, recording, or likewise. +To obtain permission to use material from this work, please submit a written +request to Martin Ruckert, +Hochschule M\"unchen, +Fakult\"at f\"ur Informatik und Mathematik, +Lothstrasse 64, +80335 M\"unchen, +Germany. +\medskip +{\tt ruckert\:@@cs.hm.edu} +\medskip +ISBN-13: 979-854992684-4\par +\medskip +First printing: August 2019\par +Second edition: August 2021\par +\medskip +Revision: \lastrevision,\quad Date: \lastdate\par +} +} +\endgroup + + +\frontmatter + + + +\plainsection{Preface} +Late in summer 2017, with my new \CEE\ based {\tt cweb} implementation +of \TeX\cite{Knuth:tex} in hand\cite{MR:webtocweb}\cite{MR:tug38}\cite{MR:web2w}, I started to write +the first prototype of the \HINT\ viewer. I basically made two copies +of \TeX: In the first copy, I replaced the |build_page| procedure by +an output routine which used more or less the printing routines +already available in \TeX. This was the beginning of the +\HINT\ file format. +In the second copy, I replaced \TeX's main loop by an input routine +that would feed the \HINT\ file more or less directly to \TeX's +|build_page| procedure. And after replacing \TeX's |ship_out| +procedure by a modified rendering routine of a dvi viewer that I had +written earlier for my experiments with \TeX's Computer Modern +fonts\cite{MR:tug37}, I had my first running \HINT\ viewer. My +sabbatical during the following Fall term gave me time for ``rapid +prototyping'' various features that I considered necessary for +reflowable \TeX\ output\cite{MR:tug39}. + +The textual output format derived from the original \TeX\ debugging +routines proved to be insufficient when I implemented a ``page up'' +button because it did not support reading the page content +``backwards''. As a consequence, I developed a compact binary file +format that could be parsed easily in both directions. The \HINT\ +short file format war born. I stopped an initial attempt at +eliminating the old textual format because it was so much nicer when +debugging. Instead, I converted the long textual format into the short +binary format as a preliminary step in the viewer. This was not a long +term solution. When opening a big file, as produced from a 1000 +pages \TeX\ file, the parsing took several seconds before the first +page would appear on screen. This delay, observed on a fast desktop +PC, is barley tolerable, and the delay one would expect on a low-cost, +low-power, mobile device seemed prohibitive. The consequence is +simple: The viewer will need an input file in the short format; and to +support debugging (or editing), separate programs are needed to +translate the short format into the long format and back again. But +for the moment, I did not bother to implement any of this but +continued with unrestricted experimentation. + +With the beginning of the Spring term 2018, I stopped further +experiments with the \HINT\ viewer and decided that I had to write +down a clean design of the \HINT\ file format. Or of both file +formats? Professors are supposed to do research, and hence I tried an +experiment: Instead of writing down a traditional language +specification, I decided to stick with the ``literate programming'' +paradigm\cite{Knuth:lp} and write the present book. It describes and implements +the \.{stretch} and \.{shrink} programs translating one file format +into the other. As a side effect, it contains the underlying language +specification. Whether this experiment is a success as a language +specification remains to be seen, and you should see for yourself. But +the only important measure for the value of a scientific experiment is +how much you can learn form it---and I learned a lot. + +The whole project turned out to be much more difficult than I had +expected. Early on, I decided that I would use a recursive descent +parser for the short format and an LR($k$) parser for the long +format. Of course, I would use {\tt lex}/{\tt flex} and {\tt yacc}/{\tt bison} +to generate the LR($k$) parser, and so I had to extend the {\tt +cweb} tools\cite{Knuth:cweb} to support the corresponding source files. + +About in mid May, after writing down about 100 pages, the first +problems emerged that could not be resolved with my current +approach. I had started to describe font definitions containing +definitions of the interword glue and the default hyphen, and the +declarative style of my exposition started to conflict with the +sequential demands of writing an output file. So it was time for a +first complete redesign. Two more passes over the whole book were +necessary to find the concepts and the structure that would allow me +to go forward and complete the book as you see it now. + +While rewriting was on its way, many ``nice ideas'' were pruned from +the book. For example, the initial idea of optimizing the \HINT\ file +while translating it was first reduced to just gathering statistics +and then disappeared completely. The added code and complexity was +just too distracting. + +What you see before you is still a snapshot of the \HINT\ file format +because its development is still under way. We will know what +features are needed for a reflowable \TeX\ file format only after many +people have started using the format. To use the format, the end-user +will need implementations, and the implementer will need a language +specification. The present book is the first step in an attempt to +solve this ``chicken or egg'' dilemma. + + +\vskip 1cm +\noindent {\it M\"unchen\hfil\break +August 20, 2019 \hfill Martin Ruckert} + + +\tableofcontent +%\thefigindex + + +\mainmatter + +\section{Introduction}\label{intro} +This book defines a file format for reflowable text. +Actually it describes two file formats: a long format +that optimizes readability for human beings, and +a short format that optimizes readability for machines +and the use of storage space. Both formats use the concept of nodes and lists of +nodes to describe the file content. Programs that process these nodes +will likely want to convert the compressed binary representation of a +node---the short format---or the lengthy textual representation of a +node---the long format---into a convenient internal representation. +So most of what follows is just a description of these nodes: their short format, +their long format and sometimes their internal representation. +Where as the description of the long and short external format is part +of the file specification, the description of the internal representation +is just informational. Different internal representations can be chosen +based on the individual needs of the program. + +While defining the format, I illustrate the processing of long and short format +files by implementing two utilities: \.{shrink} and \.{stretch}. +\.{shrink} converts the long format into the short format and \.{stretch} +goes the other way. + +There is also a prototype viewer for this +file format and a special version of \TeX\cite{DK:texbook} to produce output +in this format. Both are not described here; a survey describing +them can be found in \cite{MR:tug39}. + +\subsection{Glyphs} +Let's start with a simple and very common kind of node: a node describing +a character. +Because we describe a format that is used to display text, +we are not so much interested in the +character itself but we are interested in the specific glyph\index{glyph}. +In typography, a glyph is a unique mark to be placed on the page representing +a character. For example the glyph representing the character `a' can have +many forms among them `{\it a\/}', `{\bf a}', or `{\tenss a}'. +Such glyphs come in collections, called fonts, representing every character +of the alphabet in a consistent way. + +The long format of a node describing the glyph `a' + might look like this:`` \.{<glyph} \.{97} \.{*1>}''. +Here ``\.{97}'' is the character code which +happens to be the ASCII code of the letter `a' and ``{\tt *1}'' is a font reference +that stands for ``Computer Modern Roman 10pt''. +Reference numbers, as you can see, +start with an asterisk reminiscent of references in the \CEE\ programming language. +The Astrix enables us to distinguish between ordinary numbers like ``\.{1}'' and references like ``{\tt *1}''. + +To make this node more readable, we will see in section~\secref{chars} that it is also +possible to write `` \.{<glyph 'a' (cmr10) *1>}''. +The latter form uses a comment ``\.{(cmr10)}'', enclosed in parentheses, to +give an indication of what kind of font happens to be font 1, and it uses ``\.{'a'}'', +the character enclosed in single quotes to denote the ASCII code of `a'. +But let's keep things simple for now and stick with the decimal notation of the character code. + +The rest is common for all nodes: a keyword, here ``\.{glyph}'', and a pair of pointed brackets ``\.{<}\dots\.{>}''. + +Internally, we represent a glyph by the font number +and the character number or character code. +To store the internal representation of a glyph node, +we define an appropriate structure type, named after the node with a trailing {\dots\bf\_t}. +@<hint types@>= +typedef struct {@+ uint32_t c;@+ uint8_t f; @+} glyph_t; +@ + +Let us now look at the program \.{shrink} and see how it will convert the long format description +to the internal representation of the glyph and finally to a short format description. + + +\subsection{Scanning the Long Format} +First, \.{shrink} reads the input file and extracts a sequence of tokens. This is called ``scanning''\index{scanning}. +We generate the procedure to do the scanning using the program \.{flex}\cite{JL:flexbison}\index{flex+{\tt flex}} which is the +GNU version of the common UNIX tool \.{lex}\cite{JL:lexyacc}\index{lex+{\tt lex}}. + +The input to \.{flex} is a list of pattern/\kern -1pt action rules where the pattern is a regular +expression and the action is a piece of \CEE\ code. +Most of the time, the \CEE\ code is very simple: it just returns the right token\index{token} number +to the parser which we consider shortly. + +The code that defines the tokens will be marked with a line ending in ``\redsymbol''. +This symbol\index{symbol} stands for ``{\it Reading the long format\/}''. +These code sequences define the syntactical elements of the long format and at the same time +implement the reading process. All sections where that happens are preceded by a similar heading +and for reference they are conveniently listed together starting on page~\pageref{codeindex}. + +\codesection{\redsymbol}{Reading the Long Format}\redindex{1}{2}{Glyphs} +@s START symbol +@s END symbol +@s GLYPH symbol +@s UNSIGNED symbol +@s REFERENCE symbol + +@<symbols@>= +%token START "<" +%token END ">" +%token GLYPH "glyph" +%token <u> UNSIGNED +%token <u> REFERENCE +@ +You might notice that a small caps font is used for |START|, |END| or |GLYPH|. +These are ``terminal symbols'' or ``tokens''. +Next are the scanning rules which define the connection between tokens and their +textual representation. + +@<scanning rules@>= +::@="<"@> :< SCAN_START; return START; >: +::@=">"@> :< SCAN_END; return END; >: +::@=glyph@> :< return GLYPH; >: +::@=0|[1-9][0-9]*@> :< SCAN_UDEC(yytext); return UNSIGNED; >: +::@=\*(0|[1-9][0-9]*)@> :< SCAN_UDEC(yytext+1); return REFERENCE; >: +::@=[[:space:]]@> :< ; >: +::@=\([^()\n]*[)\n]@> :< ; >: +@ + +As we will see later, the macros starting with |SCAN_|\dots\ are scanning macros. +Here |SCAN_UDEC| is a macro that converts the decimal representation +that did match the given pattern to an unsigned integer value; it is explained in +section~\secref{integers}. +The macros |SCAN_START| and |SCAN_END| are explained in section~\secref{text}. + + +The action ``{\tt ;}'' is a ``do nothing'' action; here it causes spaces or comments\index{comment} +to be ignored. Comments start with an opening parenthesis and are terminated by a +closing parenthesis or the end of line character. +The pattern ``\.{[\^()\\n]}'' is a negated +character class that matches all characters except parentheses and the newline +character. These are not allowed inside comments. For detailed information about +the patterns used in a \.{flex} program, see the \.{flex} user manual\cite{JL:flexbison}. + +\subsection{Parsing the Long Format} +\label{parse_glyph} +Next, the tokens produced by the scanner are assembled into larger entities. +This is called ``parsing''\index{parsing}. +We generate the procedure to do the parsing using the program \.{bison}\cite{JL:flexbison}\index{bison+{\tt bison}} which is +the GNU version of the common UNIX tool \.{yacc}\cite{JL:lexyacc}\index{yacc+{\tt yacc}}. + +The input to \.{bison} is a list of parsing rules, called a ``grammar''\index{grammar}. +The rules describe how to build larger entities from smaller entities. +For a simple glyph node like `` \.{<glyph 97 *1>}'', we need just these rules: +\codesection{\redsymbol}{Reading the Long Format}%\redindex{1}{2}{Glyphs} +@s content_node symbol +@s node symbol +@s glyph symbol +@s glyph_t int +@s start symbol +@<symbols@>= +%type <u> start +%type <c> glyph +@ + +@<parsing rules@>=@/ +glyph: UNSIGNED REFERENCE @/{ $$.c=$1; REF(font_kind,$2); $$.f=$2; }; +content_node: start GLYPH glyph END { hput_tags($1,hput_glyph(&($3))); }; +start: START {HPUTNODE; $$=(uint32_t)(hpos++-hstart);} +@ + +You might notice that a slanted font is used for |glyph|, |content_node|, or |start|. +These are ``nonterminal symbols' and occur on the left hand side of a rule. On the +right hand side of a rule you find nonterminal symbols, as well as terminal\index{terminal symbol} symbols +and \CEE\ code enclosed in braces. + +Within the \CEE\ code, the expressions |$1| and |$2| refer to the variables on the parse stack +that are associated with the first and second symbol on the right hand side of the rule. +In the case of our glyph node, these will be the values 97 and 1, respectively, as produced +by the macro |SCAN_UDEC|. +|$$| refers to the variable associated with the left hand side of the rule. +These variables contain the internal representation of the object in question. +The type of the variable is specified by a mandatory {\bf token} or optional {\bf type} clause +when we define the symbol. +In the above {\bf type} clause for |start| and |glyph| , the identifiers |u| and |c| refer to +the |union| declaration of the parser (see page~\pageref{union}) +where we find |uint32_t u| and |glyph_t c|. The macro |REF| tests a reference number for +its valid range. + + +Reading a node is usually split into the following sequence of steps: +\itemize +\item Reading the node specification, here a |glyph| + consisting of an |UNSIGNED| value and a |REFERENCE| value. +\item Creating the internal representation in the variable |$$| + based on the values of |$1|, |$2|, \dots\ Here the character + code field |c| is initialized using the |UNSIGNED| value + stored in |$1| and the font field |f| is initialized using + |$2| after checking the reference number for the proper range. +\item A |content_node| rule explaining that |start| is followed by |GLYPH|, + the keyword that directs the parser to |glyph|, the + node specification, and a final |END|. +\item Parsing |start|, which is defined as the token |START| will assign + to the corresponding variable |p| on the parse stack the current + position |hpos| in the output and increments that position + to make room for the start byte, which we will discuss shortly. +\item At the end of the |content_node| rule, the \.{shrink} program calls + a {\it hput\_\dots\/} function, here |hput_glyph|, to write the short + format of the node as given by its internal representation to the output + and return the correct tag value. +\item Finally the |hput_tags| function will add the tag as a start byte and end byte + to the output stream. +\enditemize + +Now let's see how writing the short format works in detail. + + +\subsection{Writing the Short Format} +A content node in short form begins with a start\index{start byte} byte. It tells us what kind of node it is. +To describe the content of a short \HINT\ file, 32 different kinds\index{kind} of nodes are defined. +Hence the kind of a node can be stored in 5 bits and the remaining bits of the start byte +can be used to contain a 3 bit ``info''\index{info} value. + +We define an enumeration type to give symbolic names to the kind-values. +The exact numerical values are of no specific importance; +we will see in section~\secref{text}, however, that the assignment chosen below, +has certain advantages. + +Because the usage of kind-values in content nodes is +slightly different from the usage in definition nodes, we define alternative names for some kind-values. +To display readable names instead of numerical values when debugging, +we define two arrays of strings as well. Keeping the definitions consistent +is achieved by creating all definitions from the same list +of identifiers using different definitions of the macro |DEF_KIND|. + +@<hint basic types@>= +#define DEF_KIND(C,D,N) @[C##_kind=N@] +typedef enum {@+@<kinds@>@+,@+ @<alternative kind names@> @+} kind_t; +#undef DEF_KIND +@ + +@<define |content_name| and |definition_name|@>= + +#define DEF_KIND(C,D,N) @[#C@] +const char *content_name[32]=@+{@+@<kinds@>@;@+}@+; +#undef DEF_KIND@# +#define DEF_KIND(C,D,N) @[#D@] +const char *definition_name[0x20]=@+{@+@<kinds@>@;@+}@+; +#undef DEF_KIND +@ + +@<print |content_name| and |definition_name|@>= +printf("const char *content_name[32]={"); +for (k=0; k<= 31;k++) +{ printf("\"%s\"",content_name[k]); + if (k<31) printf(", "); +} +printf("};\n\n"); +printf("const char *definition_name[32]={"); +for (k=0; k<= 31;k++) +{ printf("\"%s\"",definition_name[k]); + if (k<31) printf(", "); +} +printf("};\n\n"); +@ + + + + + + +\goodbreak +\index{glyph kind+\\{glyph\_kind}} +\index{font kind+\\{font\_kind}} +\index{penalty kind+\\{penalty\_kind}} +\index{int kind+\\{int\_kind}} +\index{kern kind+\\{kern\_kind}} +\index{xdimen kind+\\{xdimen\_kind}} +\index{ligature kind+\\{ligature\_kind}} +\index{disc kind+\\{disc\_kind}} +\index{glue kind+\\{glue\_kind}} +\index{language kind+\\{language\_kind}} +\index{rule kind+\\{rule\_kind}} +\index{image kind+\\{image\_kind}} +\index{baseline kind+\\{baseline\_kind}} +\index{dimen kind+\\{dimen\_kind}} +\index{hbox kind+\\{hbox\_kind}} +\index{vbox kind+\\{vbox\_kind}} +\index{par kind+\\{par\_kind}} +\index{math kind+\\{math\_kind}} +\index{table kind+\\{table\_kind}} +\index{item kind+\\{item\_kind}} +\index{hset kind+\\{hset\_kind}} +\index{vset kind+\\{vset\_kind}} +\index{hpack kind+\\{hpack\_kind}} +\index{vpack kind+\\{vpack\_kind}} +\index{stream kind+\\{stream\_kind}} +\index{page kind+\\{page\_kind}} +\index{range kind+\\{range\_kind}} +\index{adjust kind+\\{adjust\_kind}} +\index{param kind+\\{param\_kind}} +\index{text kind+\\{text\_kind}} +\index{list kind+\\{list\_kind}} +\label{kinddef} +@<kinds@>= +DEF_KIND(t@&ext,t@&ext,0),@/ +DEF_KIND(l@&ist,l@&ist,1),@/ +DEF_KIND(p@&aram,p@&aram,2),@/ +DEF_KIND(x@&dimen,x@&dimen,3),@/ +DEF_KIND(a@&djust,a@&djust,4),@/ +DEF_KIND(g@&lyph, f@&ont,5),@/ +DEF_KIND(k@&ern,d@&imen,6),@/ +DEF_KIND(g@&lue,g@&lue,7),@/ +DEF_KIND(l@&igature,l@&igature,8),@/ +DEF_KIND(d@&isc,d@&isc,9),@/ +DEF_KIND(l@&anguage,l@&anguage,10),@/ +DEF_KIND(r@&ule,r@&ule,11),@/ +DEF_KIND(i@&mage,i@&mage,12),@/ +DEF_KIND(l@&eaders,l@&eaders,13),@/ +DEF_KIND(b@&aseline,b@&aseline,14),@/ +DEF_KIND(h@&b@&ox,h@&b@&ox,15),@/ +DEF_KIND(v@&b@&ox,v@&b@&ox,16),@/ +DEF_KIND(p@&ar,p@&ar,17),@/ +DEF_KIND(m@&ath,m@&ath,18),@/ +DEF_KIND(t@&able,t@&able,19),@/ +DEF_KIND(i@&tem,i@&tem,20),@/ +DEF_KIND(h@&set,h@&set,21),@/ +DEF_KIND(v@&set,v@&set,22),@/ +DEF_KIND(h@&pack,h@&pack,23),@/ +DEF_KIND(v@&pack,v@&pack,24),@/ +DEF_KIND(s@&tream,s@&tream,25),@/ +DEF_KIND(p@&age,p@&age,26),@/ +DEF_KIND(r@&ange,r@&ange,27),@/ +DEF_KIND(l@&ink,l@&abel,28),@/ +DEF_KIND(u@&ndefined2,u@&ndefined2,29),@/ +DEF_KIND(u@&ndefined3,u@&ndefined3,30),@/ +DEF_KIND(p@&enalty, i@&nt,31) +@t@> +@ + +For a few kind-values we have +alternative names; we will use them +to express different intentions when using them. +@<alternative kind names@>= +font_kind=glyph_kind,int_kind=penalty_kind, dimen_kind=kern_kind, label_kind=link_kind, outline_kind=link_kind@/@t{}@> +@ + +The info\index{info value} values can be used to represent numbers in the range 0 to 7; for an example +see the |hput_glyph| function later in this section. +Mostly, however, the individual bits are used as flags indicating the presence +or absence of immediate parameter values. If the info bit is set, it +means the corresponding parameter is present as an immediate value; if it +is zero, it means that there is no immediate parameter value present, and +the node specification will reveal what value to use instead. +In some cases there is a common default value that can be used, in other +cases a one byte reference number is used to select a predefined value. + +To make the binary +representation of the info bits more readable, we define an +enumeration type. + +\index{b000+\\{b000}} +\index{b001+\\{b001}} +\index{b010+\\{b010}} +\index{b011+\\{b011}} +\index{b100+\\{b100}} +\index{b101+\\{b101}} +\index{b110+\\{b110}} +\index{b111+\\{b111}} +@<hint basic types@>= +typedef enum {@+ b000=0,b001=1,b010=2,b011=3,b100=4,b101=5,b110=6,b111=7@+ } info_t; +@ + + +After the start byte follows the node content and it is the purpose of +the start byte to reveal the exact syntax and semantics of the node +content. Because we want to be able to read the short form of a \HINT\ +file in forward direction and in backward direction, the start byte is +duplicated after the content as an end\index{end byte} byte. + + +We store a kind and an info value in one byte and call this a tag. +The following macros are used to assemble and disassemble tags:\index{TAG+\.{TAG}} +@<hint macros@>= +#define @[KIND(T)@] (((T)>>3)&0x1F) +#define @[NAME(T)@] @[content_name[KIND(T)]@] +#define @[INFO(T)@] ((T)&0x7) +#define @[TAG(K,I)@] (((K)<<3)|(I)) +@ + +Writing a short format \HINT\ file is implemented by a collection of {\it hput\_\kern 1pt\dots\/} functions; +they follow most of the time the same schema: +\itemize +\item First, we define a variable for |info|. +\item Then follows the main part of the function body, where we +decide on the output format, do the actual output and set the |info| value accordingly. +\item We combine the info value with the kind-value and return the correct tag. +\item The tag value will be passed to |hput_tags| which generates +debugging information, if requested, and stores the tag before and after the node content. +\enditemize + + +After these preparations, we turn our attention again to the |hput_glyph| function. +The font number in a glyph node is between 0 and 255 and fits nicely in one byte, +but the character code is more difficult: we want to store the most common character +codes as a single byte and less frequent codes with two, three, or even four byte. +Naturally, we use the |info| bits to store the number of bytes needed for the character code. + +\codesection{\putsymbol}{Writing the Short Format}\putindex{1}{2}{Glyphs} +@<put functions@>= +static uint8_t hput_n(uint32_t n) +{@+ if (n<=0xFF) @+ + {@+HPUT8(n);@+ return 1;@+} + else if (n<=0xFFFF) @+ + {@+HPUT16(n);@+ return 2;@+} + else if (n<=0xFFFFFF)@+ + {@+HPUT24(n);@+ return 3;@+} + else @+ + {@+HPUT32(n);@+ return 4;@+} +} + +uint8_t hput_glyph(glyph_t *g) +{ info_t info; + info = hput_n(g->c); + HPUT8(g->f);@/ + return TAG(glyph_kind,info); +} +@ +The |hput_tags| function is called after the node content has been written to the +stream. It gets a the position of the start byte and the tag. With this information +it writes the start byte at the given position and the end byte at the current stream position. +@<put functions@>= +void hput_tags(uint32_t pos, uint8_t tag) +{ DBGTAG(tag,hstart+pos);DBGTAG(tag,hpos); + HPUTX(1); *(hstart+pos)=*(hpos++)=tag; @+ +} +@ + + + +The variables |hpos| and |hstart|, the macros |HPUT8|, |HPUT16|, +|HPUT24|, |HPUT32|, and |HPUTX| are all defined in +section~\secref{HPUT}; they put 8, 16, 24, or 32 bits into the output +stream and check for sufficient space in the output buffer. The macro +|DBGTAG| writes debugging output; its definition is found in +section~\secref{error_section}. + +Now that we have seen the general outline of the \.{shrink} program, +starting with a long format file and ending with a short format file, +we will look at the program \.{stretch} that reverses this +transformation. + + +\subsection{Parsing the Short Format} +The inverse of writing the short format with a {\it hput\_\kern 1pt\dots\/} function +is reading the short format with a {\it hget\_\kern 1pt\dots\/} function. + +The schema of {\it hget\_\kern 1pt\dots\/} functions reverse the schema of {\it hput\_\kern 1pt\dots\/} functions. +Here is the code for the initial and final part of a get function: + +@<read the start byte |a|@>= +uint8_t a,z; /* the start and the end byte*/ +uint32_t node_pos=hpos-hstart; +if (hpos>=hend) QUIT("Attempt to read a start byte at the end of the section"); +HGETTAG(a);@/@t{}@> +@ + +@<read and check the end byte |z|@>= +HGETTAG(z);@+ +if (a!=z) + QUIT(@["Tag mismatch [%s,%d]!=[%s,%d] at 0x%x to " SIZE_F "\n"@],@| + NAME(a),INFO(a),NAME(z),INFO(z),@|node_pos, hpos-hstart-1); +@ + + +The central routine to parse\index{parsing} the content section of a short format +file is the function |hget_content_node| which calls |hget_content| to +do most of the processing. + +|hget_content_node| will read a content node in short format and write +it out in long format: It reads the start\index{start byte} byte |a|, writes the |START| +token using the function |hwrite_start|, and based on |KIND(a)|, it +writes the node's keyword found in the |content_name| array. Then it +calls |hget_content| to read the node's content and write it out. +Finally it reads the end\index{end byte} byte, checks it against the start byte, and +finishes up the content node by writing the |END| token using the +|hwrite_end| function. The function returns the tag byte so that +the calling function might check that the content node meets its requirements. + +|hget_content| uses the start byte |a|, passed as a parameter, to +branch directly to the reading routine for the given combination of +kind and info value. The reading routine will read the data and store +its internal representation in a variable. All that the \.{stretch} +program needs to do with this internal representation is writing it in +the long format. As we will see, the call to the proper +{\it hwrite\_\kern 1pt\dots} function is included as final part of the the +reading routine (avoiding another switch statement). + + +\codesection{\getsymbol}{Reading the Short Format}\getindex{1}{2}{Content Nodes} +@<get functions@>= +void hget_content(uint8_t a); +uint8_t hget_content_node(void) +{ @<read the start byte |a|@>@;@+ hwrite_start(); + hwritef("%s",content_name[KIND(a)]); + hget_content(a);@/ + @<read and check the end byte |z|@>@; hwrite_end(); + return a; +} + +void hget_content(uint8_t a) +{@+ + switch (a)@/ + {@+ + @<cases to get content@>@;@t\1@>@/ + default: + TAGERR(a); + break;@t\2@>@/ + } +} +@ + +We implement the code to read a glyph node in two stages. +First we define a general reading macro |HGET_GLYPH(I,G)| that reads a glyph node with info value |I| into +a |glyph_t| variable |G|; then we insert this macro +in the above switch statement for all cases where it applies. +Knowing the function |hput_glyph|, the macro |HGET_GLYPH| should not be a surprise. +It reverses |hput_glyph|, storing the glyph node in its internal representation. +After that, the \.{stretch} program calls |hwrite_glyph| to produce the glyph +node in long format. + +\codesection{\getsymbol}{Reading the Short Format}\getindex{1}{2}{Glyphs} +@<get macros@>= +#define @[HGET_N(I,X)@] \ + if ((I)==1) (X)=HGET8;\ + else if ((I)==2) HGET16(X);\ + else if ((I)==3) HGET24(X);\ + else if ((I)==4) HGET32(X); + +#define @[HGET_GLYPH(I,G)@] \ + HGET_N(I,(G).c); (G).f=HGET8; @+REF_RNG(font_kind,(G).f);@/\ + hwrite_glyph(&(G));\ +@ + +Note that we allow a glyph to reference a font even before that font is defined. +This is necessary because fonts usually contain definitions---for example +the fonts hyphen character---that reference this or other fonts. + + +@<cases to get content@>= +@t\1\kern1em@>case TAG(glyph_kind,1): @+{@+glyph_t g;@+ HGET_GLYPH(1,g);@+}@+break; +case TAG(glyph_kind,2): @+{@+glyph_t g;@+ HGET_GLYPH(2,g);@+}@+break; +case TAG(glyph_kind,3): @+{@+glyph_t g;@+ HGET_GLYPH(3,g);@+}@+break; +case TAG(glyph_kind,4): @+{@+glyph_t g;@+ HGET_GLYPH(4,g);@+}@+break; +@ + +If this two stage method seems strange to you, consider what the \CEE\ compiler will +do with it. It will expand the |HGET_GLYPH| macro four times inside the switch +statement. The macro is, however, expanded with a constant |I| value, so the expansion +of the |if| statement in |HGET_GLYPH(1,g)|, for example, +will become ``|if (1==1)| \dots\ |else if (1==2)| \dots'' +and the compiler will have no difficulties eliminating the constant tests and +the dead branches altogether. This is the most effective use of the switch statement: +a single jump takes you to a specialized code to handle just the given combination +of kind and info value. + +Last not least, we implement the function |hwrite_glyph| to write a +glyph node in long form---that is: in a form that is as readable as possible. + +\subsection{Writing the Long Format} + +The |hwrite_glyph| function inverts the scanning and parsing process we have described +at the very beginning of this chapter. +To implement the |hwrite_glyph| function, we use the function |hwrite_charcode| +to write the character code. +Besides writing the character code as a decimal number, this function can handle also other +representations of character codes as fully explained in section~\secref{chars}. +We split off the writing of the opening and the closing pointed bracket, because +we will need this function very often and because it will keep track of the |nesting| +of nodes and indent them accordingly. The |hwrite_range| and |hwrite_label| functions +used in |hwrite_end| are discussed in section~\secref{range} and~\secref{hwritelabel}. + +\codesection{\wrtsymbol}{Writing the Long Format}\wrtindex{1}{2}{Glyphs} +@<write functions@>= +int nesting=0; +void hwrite_nesting(void) +{ int i; + hwritec('\n'); + for (i=0;i<nesting;i++) hwritec(' '); +} + +void hwrite_start(void) +{ @+hwrite_nesting();@+ hwritec('<');@+ nesting++; +} + +void hwrite_range(void); +void hwrite_label(void); + +void hwrite_end(void) +{ nesting--; hwritec('>'); + if (section_no==2) + { if (nesting==0) hwrite_range(); + hwrite_label(); + } +} + +void hwrite_comment(char *str) +{ char c; + if (str==NULL) return; + hwritef(" ("); + while ((c=*str++)!=0) + if (c=='(' || c==')') hwritec('_'); + else if (c=='\n') hwritef("\n("); + else hwritec(c); + hwritec(')'); +} + +void hwrite_charcode(uint32_t c); +void hwrite_ref(int n); + +void hwrite_glyph(glyph_t *g) +{ char *n=hfont_name[g->f]; + hwrite_charcode(g->c); + hwrite_ref(g->f); + if (n!=NULL) hwrite_comment(n); +} +@ + +The two primitive operations to write the long format file are defined +as macros: + +@<write macros@>= +#define @[hwritec(c)@] @[putc(c,hout)@] +#define @[hwritef(...)@] @[fprintf(hout,__VA_ARGS__)@] +@ + + +Now that we have completed the round trip of shrinking and stretching +glyph nodes, we continue the description of the \HINT\ file formats +in a more systematic way. + + +\section{Data Types}\hascode +\subsection{Integers} +\label{integers} +We have already seen the pattern/\kern -1pt action rule for unsigned decimal\index{decimal number} numbers. It remains +to define the macro |SCAN_UDEC| which converts a string containing an unsigned\index{unsigned} decimal +number into an unsigned integer\index{integer}. +We use the \CEE\ library function | strtoul|: + +\readcode +@<scanning macros@>= +#define @[SCAN_UDEC(S)@] @[yylval.u=strtoul(S,NULL,10)@] +@ +Unsigned integers can be given in hexadecimal\index{hexadecimal} notation as well. +@<scanning definitions@>= +::@=HEX@> :< @=[0-9A-F]@> >: +@ + +@<scanning rules@>= +::@=0x{HEX}+@> :< SCAN_HEX(yytext+2); return UNSIGNED; >: +@ + +Note that the pattern above allows only upper case letters in the +hexadecimal notation for integers. + +@<scanning macros@>= +#define @[SCAN_HEX(S)@] @[yylval.u=strtoul(S,NULL,16)@] +@ + +Last not least, we add rules for signed\index{signed integer} integers. +@s SIGNED symbol +@s number symbol +@s integer symbol + +@<symbols@>= +%token <i> SIGNED +%type <i> integer +@ + +@<scanning rules@>= +::@=[+-](0|[1-9][0-9]*)@> :< SCAN_DEC(yytext); return SIGNED; >: +@ + +@<scanning macros@>= +#define @[SCAN_DEC(S)@] @[yylval.i=strtol(S,NULL,10)@] +@ + +@<parsing rules@>= +integer: SIGNED @+| UNSIGNED { RNG("number",$1,0,INT32_MAX);}; +@ + +To preserve the ``signedness'' of an integer also for positive signed integers +in the long format, we implement the function |hwrite_signed|. + +\writecode +@<write functions@>= +void hwrite_signed(int32_t i) +{ if (i<0) hwritef(" -%d",-i); + else hwritef(" +%d",+i); +} +@ + +Reading and writing integers in the short format is done directly with the {\tt HPUT} and {\tt HGET} +macros. + + +\subsection{Strings} +\label{strings} +Strings\index{string} are needed in the definition part of a \HINT\ +file to specify names of objects, and in the long file format, we also use them for file\index{file name} names. +In the long format, strings are sequences of characters delimited by single quote\index{single quote} characters; +for example: ``\.{'Hello'}'' or ``\.{'cmr10-600dpi.tfm'}''; in the short format, strings are +byte sequences terminated by a zero byte. +Because file names are system dependent, we no not allow arbitrary characters in strings +but only printable ASCII codes which we can reasonably expect to be available on most operating systems. +If your file names in a long format \HINT\ file are supposed to be portable, +you should probably be even more restrictive. For example you should avoid characters like +``\.{\\}'' or ``\.{/}'' which are used in different ways for directories. + +The internal representation of a string is a simple zero terminated \CEE\ string. +When scanning a string, we copy it to the |str_buffer| keeping track +of its length in |str_length|. When done, +we make a copy for permanent storage and return the pointer to the parser. +To operate on the |str_buffer|, we define a few macros. +The constant |MAX_STR| determines the maximum size of a string (including the zero byte) to be $2^{10}$ byte. +This restriction is part of the \HINT\ file format specification. + +@<scanning macros@>= +#define MAX_STR (1<<10) /* $2^{10}$ Byte or 1kByte */ +static char str_buffer[MAX_STR]; +static int str_length; +#define STR_START @[(str_length=0)@] +#define @[STR_PUT(C)@] @[(str_buffer[str_length++]=(C))@] +#define @[STR_ADD(C)@] @[STR_PUT(C);RNG("String length",str_length,0,MAX_STR-1)@] +#define STR_END @[str_buffer[str_length]=0@] +#define SCAN_STR @[yylval.s=str_buffer@] +@ + + +To scan a string, we switch the scanner to |STR| mode when we find a quote character, +then we scan bytes in the range |0x20| to |0x7E|, which is the range of printable ASCII +characters, until we find the closing single\index{single quote} quote. +Quote characters inside the string are written as two consecutive single quote characters. + +\readcode +@s STRING symbol +@s STR symbol +@s INITIAL symbol + +@<scanning definitions@>= +%x STR +@ + +@<symbols@>= +%token <s> STRING +@ + +@<scanning rules@>= +::@='@> :< STR_START; BEGIN(STR); >: +<STR>{ +::@='@> :< STR_END; SCAN_STR; BEGIN(INITIAL); return STRING; >: +::@=''@> :< STR_ADD('\''); >: +::@=[\x20-\x7E]@> :< STR_ADD(yytext[0]); >: +::@=.@> :< RNG("String character",yytext[0],0x20,0x7E); >: +::@=\n@> :< QUIT("Unterminated String in line %d",yylineno); >: +} + + +@ +The function |hwrite_string| reverses this process; it must take care of the quote symbols. +\writecode +@<write functions@>= +void hwrite_string(char *str) +{@+hwritec(' '); + if (str==NULL) hwritef("''"); + else@/ + { hwritec('\''); + while (*str!=0)@/ + { @+if (*str=='\'') hwritec('\''); + hwritec(*str++); + } + hwritec('\''); + } +} + + +@ +In the short format, a string is just a byte sequence terminated by a zero byte. +This makes the function |hput_string|, to write a string, and the macro |HGET_STRING|, +to read a string in short format, very simple. Note that after writing an unbounded +string to the output buffer, the macro |HPUTNODE| will make sure that there is enough +space left to write the remainder of the node. + +\putcode +@<put functions@>= +void hput_string(char *str) +{ char *s=str; + if (s!=NULL) + { do { + HPUTX(1); + HPUT8(*s); + } while (*s++!=0); + HPUTNODE; + } + else HPUT8(0); +} +@ + +\getcode +@<shared get macros@>= +#define @[HGET_STRING(S)@] @[S=(char*)hpos;\ + while(hpos<hend && *hpos!=0) { RNG("String character",*hpos,0x20,0x7E); hpos++;}\ + hpos++; +@ + +\subsection{Character Codes} +\label{chars} +We have already seen in the introduction that character\index{character code} codes can be written as decimal numbers +and section~\secref{integers} adds the possibility to use hexadecimal numbers as well. + +It is, however, in most cases more readable if we represent character codes directly +using the characters themselves. Writing ``\.{a}'' is just so much better than writing ``\.{97}''. +To distinguish the character ``\.{9}'' from the number ``\.{9}'', we use the common technique +of enclosing characters within single\index{single quote} quotes. So ``\.{'9'}'' is the character code and +``\.{9}'' is the number. +Therefore we will define |CHARCODE| tokens and complement the parsing rules of section~\secref{parse_glyph} +with the following rule: +\readcode +@<parsing rules@>= +glyph: CHARCODE REFERENCE @|{ $$.c=$1; REF(font_kind,$2); $$.f=$2; }; +@ + + + +If the character codes are small, we can represent them using +ASCII character codes. We do not offer a special notation for very small +character codes that map to the non-printable ASCII control codes; for them, the decimal +or hexadecimal notation will suffice. +For larger character codes, we use the multibyte encoding scheme known from UTF8\index{UTF8} as +follows. Given a character code~|c|: + +\itemize +\item +Values in the range |0x00| to |0x7f| are encoded as a single byte with a leading bit of 0. + +@<scanning definitions@>= +::@=UTF8_1@> :< @=[\x00-\x7F]@> >: +@ +@<scanning macros@>= +#define @[SCAN_UTF8_1(S)@] @[yylval.u=((S)[0]&0x7F)@] +@ + + +\item +Values in the range |0x80| to |0x7ff| are encoded in two byte with the first byte +having three high bits |110|, indicating a two byte sequence, and the lower five bits equal +to the five high bits of |c|. It is followed by a continuation byte having two high bits |10| +and the lower six bits +equal to the lower six bits of |c|. + +@<scanning definitions@>= +::@=UTF8_2@> :< @=[\xC0-\xDF][\x80-\xBF]@> >: +@ + +@<scanning macros@>= +#define @[SCAN_UTF8_2(S)@] @[yylval.u=(((S)[0]&0x1F)<<6)+((S)[1]&0x3F)@] +@ + +\item +Values in the range |0x800| to |0xFFFF| are encoded in three byte with the first byte +having the high bits |1110| indicating a three byte sequence followed by two continuation bytes. + +@<scanning definitions@>= +::@=UTF8_3@> :< @=[\xE0-\xEF][\x80-\xBF][\x80-\xBF]@> >: +@ + +@<scanning macros@>= +#define @[SCAN_UTF8_3(S)@] @[yylval.u=(((S)[0]&0x0F)<<12)+(((S)[1]&0x3F)<<6)+((S)[2]&0x3F)@] +@ + +\item +Values in the range |0x1000| to |0x1FFFFF| are encoded in four byte with the first byte +having the high bits |11110| indicating a four byte sequence followed by three continuation bytes. + +@<scanning definitions@>= +::@=UTF8_4@> :< @=[\xF0-\xF7][\x80-\xBF][\x80-\xBF][\x80-\xBF]@> >: +@ + +@<scanning macros@>= +#define @[SCAN_UTF8_4(S)@] @[yylval.u=(((S)[0]&0x03)<<18)+(((S)[1]&0x3F)<<12)+@|(((S)[2]&0x3F)<<6)+((S)[3]&0x3F)@] +@ + +\enditemize + +In the long format file, we enclose a character code in single\index{single quote} quotes, just as we do for strings. +This is convenient but it has the downside that we must exercise special care when giving the +scanning rules in order +not to confuse character codes with strings. Further we must convert character codes back into strings +in the rare case where the parser expects a string and gets a character code because the string +was only a single character long. + +Let's start with the first problem: +The scanner might confuse a string\index{string} and a character code if the first or second +character of the string is a quote character which is written as two consecutive quotes. +For example \.{'a''b'} is a string with three characters, ``\.{a}'', +``\.{'}'', and ``\.{b}''. Two character codes would need a space to separate +them like this: \.{'a' 'b'}. + + +@s CHARCODE symbol +@<symbols@>= +%token <u> CHARCODE +@ + +@<scanning rules@>= +::@='''@> :< STR_START; STR_PUT('\''); BEGIN(STR); >: +::@=''''@> :< SCAN_UTF8_1(yytext+1); return CHARCODE; >: +::@='[\x20-\x7E]''@> :< STR_START; STR_PUT(yytext[1]); STR_PUT('\''); BEGIN(STR); >: +::@='''''@> :< STR_START; STR_PUT('\''); STR_PUT('\''); BEGIN(STR); >: +::@='{UTF8_1}'@> :< SCAN_UTF8_1(yytext+1); return CHARCODE; >: +::@='{UTF8_2}'@> :< SCAN_UTF8_2(yytext+1); return CHARCODE; >: +::@='{UTF8_3}'@> :< SCAN_UTF8_3(yytext+1); return CHARCODE; >: +::@='{UTF8_4}'@> :< SCAN_UTF8_4(yytext+1); return CHARCODE; >: +@ + +If needed, the parser can convert character codes back to single character strings. + +@s string symbol + +@<symbols@>= +%type <s> string +@ + +@<parsing rules@>= +string: STRING @+ | CHARCODE { static char s[2]; + RNG("String element",$1,0x20,0x7E); + s[0]=$1; s[1]=0; $$=s;}; +@ + + +The function |hwrite_charcode| will write a character code. While ASCII codes are handled directly, +larger character codes are passed to the function |hwrite_utf8|. +It returns the number of characters written. + +\writecode +@<write functions@>= +int hwrite_utf8(uint32_t c) +{@+ if (c<0x80) + { hwritec(c); @+return 1;@+ } + else if (c<0x800)@/ + { hwritec(0xC0|(c>>6));@+ hwritec(0x80|(c&0x3F));@+ return 2;@+} + else if (c<0x10000)@/ + { hwritec(0xE0|(c>>12)); hwritec(0x80|((c>>6)&0x3F));@+ hwritec(0x80|(c&0x3F)); return 3; } + else if (c<0x200000)@/ + { hwritec(0xF0|(c>>18));@+ hwritec(0x80|((c>>12)&0x3F)); + hwritec(0x80|((c>>6)&0x3F));@+ hwritec(0x80|(c&0x3F)); return 4;} + else + RNG("character code",c,0,0x1FFFFF); + return 0; +} + +void hwrite_charcode(uint32_t c) +{ @+if (c < 0x20) + { if (option_hex) hwritef(" 0x%02X",c); /* non printable ASCII */ + else hwritef(" %u",c); + } + else if (c=='\'') hwritef(" ''''"); + else if (c<=0x7E) hwritef(" \'%c\'",c); /* printable ASCII */ + else if (option_utf8) { hwritef(" \'"); @+ hwrite_utf8(c); @+ hwritec('\'');@+} + else if (option_hex) hwritef(" 0x%04X",c); + else hwritef(" %u",c); +} +@ + +\getcode +@<shared get functions@>= +#define @[HGET_UTF8C(X)@] (X)=HGET8;@+ if ((X&0xC0)!=0x80) \ + QUIT(@["UTF8 continuation byte expected at " SIZE_F " got 0x%02X\n"@],hpos-hstart-1,X)@; + +uint32_t hget_utf8(void) +{ uint8_t a; + a=HGET8; + if (a<0x80) return a; + else + { if ((a&0xE0)==0xC0) @/ + { uint8_t b; @+ HGET_UTF8C(b); + return ((a&~0xE0)<<6)+(b&~0xC0); + } + else if ((a&0xF0)==0xE0) @/ + { uint8_t b,c; @+ HGET_UTF8C(b); @+ HGET_UTF8C(c); + return ((a&~0xF0)<<12)+((b&~0xC0)<<6)+(c&~0xC0); + } + else if ((a&0xF8)==0xF0) @/ + { uint8_t b,c,d; @+ HGET_UTF8C(b); @+ HGET_UTF8C(c); @+ HGET_UTF8C(d); + return ((a&~0xF8)<<18)@|+ ((b&~0xC0)<<12)+((c&~0xC0)<<6)+(d&~0xC0); + } + else QUIT("UTF8 byte sequence expected"); + } +} +@ +\putcode +@<put functions@>= +void hput_utf8(uint32_t c) +{ @+HPUTX(4); + if (c<0x80) + HPUT8(c); + else if (c<0x800) + { HPUT8(0xC0|(c>>6));@+ HPUT8(0x80|(c&0x3F));@+ } + else if (c<0x10000)@/ + { HPUT8(0xE0|(c>>12)); HPUT8(0x80|((c>>6)&0x3F));@+ HPUT8(0x80|(c&0x3F)); } + else if (c<0x200000)@/ + { HPUT8(0xF0|(c>>18));@+ HPUT8(0x80|((c>>12)&0x3F)); + HPUT8(0x80|((c>>6)&0x3F));@+ HPUT8(0x80|(c&0x3F)); } + else + RNG("character code",c,0,0x1FFFFF); +} +@ + +\subsection{Floating Point Numbers} +You know a floating point numbers\index{floating point number} when you see it because it features a radix\index{radix point} point. +The optional exponent\index{exponent} allows you to ``float'' the point. + +\readcode +@s FPNUM symbol +@s number symbol + +@<symbols@>= +%token <f> FPNUM +%type <f> number +@ +@<scanning rules@>= +::@=[+-]?[0-9]+\.[0-9]+(e[+-]?[0-9])?@> :< SCAN_DECFLOAT; return FPNUM; >: +@ + +The layout of floating point variables of type |double| +or |float| typically follows the IEEE754\index{IEEE754} standard\cite{IEEE754-1985}\cite{IEEE754-2008}. +We use the following definitions: + +\index{float32 t+\&{float32\_t}} +\index{float64 t+\&{float64\_t}} + +@<hint basic types@>= + +#define FLT_M_BITS 23 +#define FLT_E_BITS 8 +#define FLT_EXCESS 127 + +#define DBL_M_BITS 52 +#define DBL_E_BITS 11 +#define DBL_EXCESS 1023 + +@ + +@s float32_t int +@s float64_t int + +We expect a variable of type |float64_t| to have a binary representation using 64 bit. +The most significant bit is the sign bit, then follow $|DBL_E_BITS|=11$ bits for +the exponent\index{exponent}, and $|DBL_M_BITS|=52$ bits for the mantissa\index{mantissa}. +The sign\index{sign bit} bit is 1 for a negative number and 0 for a positive number. +A floating point number is stored in normalized\index{normalization} form which means that +the mantissa is shifted such that it has exactly 52+1 bit not counting leading zeros. +The leading bit is then always 1 and there is no need to store it. So 52 bits suffice. +To store the exponent, the excess $q=1023$ is added and the result is stored as an +unsigned 11 bit number. +For example if we regard the exponent bits and the mantissa bits as unsigned binary numbers +$e$ and $m$ then the absolute value of such a floating point number can be expressed +as $(1+m*2^{-52})\cdot2^{e-1023}$. +We make similar assumptions about variables of type |float32_t| using the constants as defined above. + + + + + +To convert the decimal representation of a floating point number to binary values of type |float64_t|, +we use a \CEE\ library function. + +@<scanning macros@>= +#define SCAN_DECFLOAT @[yylval.f=atof(yytext)@] +@ + +When the parser expects a floating point number and gets an integer number, +it converts it. So whenever in the long format a floating point number is expected, +an integer number will do as well. + +@<parsing rules@>= +number: UNSIGNED {$$=(float64_t)$1; } | SIGNED {$$=(float64_t)$1; } | FPNUM; +@ + +Unfortunately the decimal representation is not optimal for floating point numbers +since even simple numbers in decimal notation like $0.1$ do not have an exact +representation as a binary floating point number. +So if we want a notation that allows an exact representation +of binary floating point numbers, we must use a hexadecimal\index{hexadecimal} representation. +Hexadecimal floating point numbers start with an optional sign, then as usual the two characters ``{\tt 0x}'', +then follows a sequence of hex digits, a radix point, more hex digits, and an optional exponent. +The optional exponent starts with the character ``{\tt x}'', followed by an optional sign, and some more +hex digits. The hexadecimal exponent is given as a base 16 number and it is interpreted as an exponent +with the base 16. As an example an exponent of ``{\tt x10}'', would multiply the mantissa by $16^{16}$. +In other words it would shift any mantissa 16 hexadecimal digits to the left. Here are the exact rules: + +@<scanning rules@>= +::@=[+-]?0x{HEX}+\.{HEX}+(x[+-]?{HEX}+)?@> :< SCAN_HEXFLOAT; return FPNUM; >: +@ + +@<scanning macros@>= +#define SCAN_HEXFLOAT @[yylval.f=xtof(yytext)@] +@ +There is no function in the \CEE\ library for hexadecimal floating point notation +so we have to write our own conversion routine. +The function |xtof| converts a string matching the above regular expression to +its binary representation. Its outline is very simple: + +@<scanning functions@>= + +float64_t xtof(char *x) +{ int sign, digits, exp; + uint64_t mantissa=0; + DBG(DBGFLOAT,"converting %s:\n",x); + @<read the optional sign@>@; + x=x+2; /* skip ``\.{0x}'' */ + @<read the mantissa@>@; + @<normalize the mantissa@>@; + @<read the optional exponent@>@; + @<return the binary representation@>@; +} +@ + +Now the pieces: + +@<read the optional sign@>= + if (*x=='-') { sign=-1;@+ x++;@+ } + else if (*x=='+') { sign=+1;@+ x++;@+ } + else @+sign=+1; + DBG(DBGFLOAT,"\tsign=%d\n",sign); +@ + +When we read the mantissa, we use the temporary variable |mantissa|, keep track +of the number of digits, and adjust the exponent while reading the fractional part. +@<read the mantissa@>= + digits=0; + while (*x=='0') x++; /*ignore leading zeros*/ + while (*x!='.')@/ + { mantissa=mantissa<<4; + if (*x<'A') mantissa=mantissa+*x-'0'; + else mantissa=mantissa+*x-'A'+10; + x++; + digits++; + } + x++; /* skip ``\.{.}'' */ + exp=0; + while (*x!=0 && *x!='x')@/ + { mantissa=mantissa<<4; + exp=exp-4; + if (*x<'A') mantissa=mantissa+*x-'0'; + else mantissa=mantissa+*x-'A'+10; + x++; + digits++; + } + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 ", exp=%d\n",@|digits,mantissa,exp); +@ + +To normalize the mantissa, first we shift it to place exactly one nonzero hexadecimal +digit to the left of the radix point. Then we shift it right bit-wise until there is +just a single 1 bit to the left of the radix point. +To compensate for the shifting, we adjust the exponent accordingly. +Finally we remove the most significant bit because it is +not stored. + +@<normalize the mantissa@>= +if (mantissa==0) return 0.0; +{ int s; + s = digits-DBL_M_BITS/4; + if (s>1) + mantissa=mantissa>>(4*(s-1)); + else if (s<1) + mantissa=mantissa<<(4*(1-s)); + exp=exp+4*(digits-1); + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 ", exp=%d\n",@|digits,mantissa,exp); + while ((mantissa>>DBL_M_BITS)>1)@/ { mantissa=mantissa>>1; @+ exp++;@+ } + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 ", exp=%d\n",@|digits,mantissa,exp); + mantissa=mantissa&~((uint64_t)1<<DBL_M_BITS); + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 ", exp=%d\n",@|digits,mantissa,exp); +} +@ + +In the printed representation, +the exponent is an exponent with base 16. For example, an exponent of 2 shifts +the hexadecimal mantissa two hexadecimal digits to the left, which corresponds to a +multiplication by ${16}^2$. + +@<read the optional exponent@>= + if (*x=='x')@/ + { int s; + x++; /* skip the ``\.{x}'' */ + if (*x=='-') {s=-1;@+x++;@+} + else if (*x=='+') {s=+1;@+x++;@+} + else s=+1; + DBG(DBGFLOAT,"\texpsign=%d\n",s); + DBG(DBGFLOAT,"\texp=%d\n",exp); + while (*x!=0 ) + { if (*x<'A') exp=exp+4*s*(*x-'0'); + else exp=exp+4*s*(*x-'A'+10); + x++; + DBG(DBGFLOAT,"\texp=%d\n",exp); + } + } + RNG("Floating point exponent",@|exp,-DBL_EXCESS,DBL_EXCESS); +@ + +To assemble the binary representation, we use a |union| of a |float64_t| and |uint64_t|. + + +@<return the binary representation@>= +{ union {@+float64_t d; @+uint64_t bits; @+} u; + if (sign<0) sign=1;@+ else@+ sign=0; /* the sign bit */ + exp=exp+DBL_EXCESS; /* the exponent bits */ + u.bits=((uint64_t)sign<<63)@/ + | ((uint64_t)exp<<DBL_M_BITS) | mantissa; + DBG(DBGFLOAT," return %f\n",u.d); + return u.d; +} +@ + +The inverse function is |hwrite_float64|. It strives to print floating point numbers +as readable as possible. So numbers without fractional part are written as integers. +Numbers that can be represented exactly in decimal notation are represented in +decimal notation. All other values are written as hexadecimal floating point numbers. +We avoid an exponent if it can be avoided by using up to |MAX_HEX_DIGITS| + +\writecode +@<write functions@>= +#define MAX_HEX_DIGITS 12 +void hwrite_float64(float64_t d) +{ uint64_t bits, mantissa; + int exp, digits; + hwritec(' '); + if (floor(d)==d) + { hwritef("%d",(int)d);@+ return;@+} + if (floor(10000.0*d)==10000.0*d) + { hwritef("%g",d); @+return;@+} + DBG(DBGFLOAT,"Writing hexadecimal float %f\n",d); + if (d<0) { hwritec('-');@+ d=-d;@+} + hwritef("0x"); + @<extract mantissa and exponent@>@; + if (exp>MAX_HEX_DIGITS) + @<write large numbers@>@; + else if (exp>=0) @<write medium numbers@>@; + else @<write small numbers@>@; +} +@ + +The extraction just reverses the creation of the binary representation. + +@<extract mantissa and exponent@>= +{ union {@+float64_t d; @+ uint64_t bits; @+} u; + u.d=d; @+ bits=u.bits; +} + mantissa= bits&(((uint64_t)1<<DBL_M_BITS)-1); + mantissa=mantissa+((uint64_t)1<<DBL_M_BITS); + exp= ((bits>>DBL_M_BITS)&((1<<DBL_E_BITS)-1))-DBL_EXCESS; + digits=DBL_M_BITS+1; + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 " binary exp=%d\n",@|digits,mantissa,exp); +@ + +After we have obtained the binary exponent, +we round it down, and convert it to a hexadecimal +exponent. +@<extract mantissa and exponent@>= + { int r; + if (exp>=0) + { r= exp%4; + if (r>0) + { mantissa=mantissa<<r; @+exp=exp-r; @+digits=digits+r; @+} + } + else + { r=(-exp)%4; + if (r>0) + { mantissa=mantissa>>r; @+exp=exp+r; @+digits=digits-r;@+} + } + } + exp=exp/4; + DBG(DBGFLOAT,"\tdigits=%d mantissa=0x%" PRIx64 " hex exp=%d\n",@|digits,mantissa,exp); +@ + +In preparation for writing, +we shift the mantissa to the left so that the leftmost hexadecimal +digit of it will occupy the 4 leftmost bits of the variable |bits| . + +@<extract mantissa and exponent@>= + mantissa=mantissa<<(64-DBL_M_BITS-4); /* move leading digit to leftmost nibble */ +@ + +If the exponent is larger than |MAX_HEX_DIGITS|, we need to +use an exponent even if the mantissa uses only a few digits. +When we use an exponent, we always write exactly one digit preceding the radix point. + +@<write large numbers@>= +{ DBG(DBGFLOAT,"writing large number\n"); + hwritef("%X.",(uint8_t)(mantissa>>60)); + mantissa=mantissa<<4; + do { + hwritef("%X",(uint8_t)(mantissa>>DBL_M_BITS)&0xF); + mantissa=mantissa<<4; + } while (mantissa!=0); + hwritef("x+%X",exp); +} +@ +If the exponent is small and non negative, we can write the +number without an exponent by writing the radix point at the +appropriate place. + @<write medium numbers@>= + { DBG(DBGFLOAT,"writing medium number\n"); + do { + hwritef("%X",(uint8_t)(mantissa>>60)); + mantissa=mantissa<<4; + if (exp--==0) hwritec('.'); + } while (mantissa!=0 || exp>=-1); + } +@ +Last non least, we write numbers that would require additional zeros after the +radix point with an exponent, because it keeps the mantissa shorter. +@<write small numbers@>= + { DBG(DBGFLOAT,"writing small number\n"); + hwritef("%X.",(uint8_t)(mantissa>>60)); + mantissa=mantissa<<4; + do { + hwritef("%X",(uint8_t)(mantissa>>60)); + mantissa=mantissa<<4; + } while (mantissa!=0); + hwritef("x-%X",-exp); + } +@ + +Compared to the complications of long format floating point numbers, +the short format is very simple because we just use the binary representation. +Since 32 bit floating point numbers offer sufficient precision we use only +the |float32_t| type. +It is however not possible to just write |HPUT32(d)| for a |float32_t| variable |d| +or |HPUT32((uint32_t)d)| because in the \CEE\ language this would imply +rounding the floating point number to the nearest integer. +But we have seen how to convert floating point values to bit pattern before. + +@<put functions@>= +void hput_float32(float32_t d) +{ union {@+float32_t d; @+ uint32_t bits; @+} u; + u.d=d; @+ HPUT32(u.bits); +} +@ + +@<shared get functions@>= +float32_t hget_float32(void) +{ union {@+float32_t d; @+ uint32_t bits; @+} u; + HGET32(u.bits); + return u.d; +} +@ + +\subsection{Fixed Point Numbers} +\TeX\ internally represents most real numbers as fixed\index{fixed point number} point numbers or ``scaled integers''\index{scaled integer}. +The type {\bf scaled\_t} is defined as a signed 32 bit integer, but we consider it as a fixed point number +with the binary radix point just in the middle with sixteen bits before and sixteen bits after it. +To convert an integer into a scaled number, we multiply it by |ONE|; to convert a floating point number +into a scaled number, we multiply it by |ONE| and |ROUND| the result to the nearest integer; +to convert a scaled number to a floating point number we divide it by |(float64_t)ONE|. + +\noindent +@<hint basic types@>= +typedef int32_t scaled_t; +#define ONE ((scaled_t)(1<<16)) +@ + +@<hint macros@>= +#define ROUND(X) ((int)((X)>=0.0?floor((X)+0.5):ceil((X)-0.5))) +@ + +\writecode +@<write functions@>= +void hwrite_scaled(scaled_t x) +{ hwrite_float64(x/(float64_t)ONE); +} +@ + +\subsection{Dimensions} +In the long format, +the dimensions\index{dimension} of characters, boxes, and other things can be given +in three units: \.{pt}, \.{in}, and \.{mm}. + +\readcode +@s PT symbol +@s MM symbol +@s INCH symbol +@s dimension symbol +@s DIMEN symbol +@<symbols@>= +%token DIMEN "dimen" +%token PT "pt" +%token MM "mm" +%token INCH "in" +%type <d> dimension +@ + +@<scanning rules@>= +::@=dimen@> :< return DIMEN; >: +::@=pt@> :< return PT; >: +::@=mm@> :< return MM; >: +::@=in@> :< return INCH; >: +@ + +The unit \.{pt} is a printers point\index{point}\index{pt+{\tt pt}}. +The unit ``\.{in}'' stands for inches\index{inch}\index{in+{\tt in}} and we have $1\.{in}= 72.27\,\.{pt}$. +The unit ``\.{mm}'' stands for millimeter\index{millimeter}\index{mm+{\tt mm}} and we have $1\.{in}= 25.4\,\.{mm}$. + +The definition of a printers\index{printers point} point given above follows the definition used in +\TeX\ which is slightly larger than the official definition of a printer's +point which was defined to equal exactly 0.013837\.{in} by the American Typefounders +Association in~1886\cite{DK:texbook}. + +We follow the tradition of \TeX\ and +store dimensions as ``scaled points''\index{scaled point} that is a dimension of $d$ points is +stored as $d\cdot2^{16}$ rounded to the nearest integer. +The maximum absolute value of a dimension is $(2^{30}-1)$ scaled points. + +@<hint basic types@>= +typedef scaled_t dimen_t; +#define MAX_DIMEN ((dimen_t)(0x3FFFFFFF)) +@ + +@<parsing rules@>= +dimension: number PT @|{$$=ROUND($1*ONE); RNG("Dimension",$$,-MAX_DIMEN,MAX_DIMEN); } + | number INCH @|{$$=ROUND($1*ONE*72.27); RNG("Dimension",$$,-MAX_DIMEN,MAX_DIMEN);@+} + | number MM @|{$$=ROUND($1*ONE*(72.27/25.4)); RNG("Dimension",$$,-MAX_DIMEN,MAX_DIMEN);@+}; +@ + +When \.{stretch} is writing dimensions in the long format, +for simplicity it always uses the unit ``\.{pt}''. +\writecode +@<write functions@>= +void hwrite_dimension(dimen_t x) +{ hwrite_scaled(x); + hwritef("pt"); +} +@ + +In the short format, dimensions are stored as 32 bit scaled point values without conversion. +\getcode +@<get functions@>= +void hget_dimen(uint8_t a) +{ if (INFO(a)==b000) + {uint8_t r; r=HGET8; REF(dimen_kind,r); hwrite_ref(r);} + else + { uint32_t d; HGET32(d); hwrite_dimension(d); } +} +@ + +\putcode +@<put functions@>= + +uint8_t hput_dimen(dimen_t d) +{ HPUT32(d); + return TAG(dimen_kind, b001); +} +@ + + + +\subsection{Extended Dimensions}\index{extended dimension}\index{hsize+{\tt hsize}}\index{vsize+{\tt vsize}} +The dimension that is probably used most frequently in a \TeX\ file is {\tt hsize}: +the ho\-ri\-zon\-tal size of a line of text. Common are also assignments +like \.{\\hsize=0.5\\hsize} \.{\\advance\\hsize by -10pt}, for example to +get two columns with lines almost half as wide as usual, leaving a small gap +between left and right column. Similar considerations apply to {\tt vsize}. + +Because we aim at a reflowable format for \TeX\ output, we have to postpone +such computations until the values of \.{hsize} and \.{vsize} are known in the viewer. +Until then, we do symbolic computations on linear functions\index{linear function} of \.{hsize} and \.{vsize}. +We call such a linear function $w+h\cdot\.{hsize}+v\cdot\.{vsize}$ +an extended dimension and represent it by the three numbers $w$, $h$, and $v$. + +@<hint basic types@>= +typedef struct {@+ +dimen_t w; @+ float32_t h, v; @+ +} xdimen_t; +@ +Since very often a component of an extended dimension is zero, we +store in the short format only the nonzero components and use the +info bits to mark them: |b100| implies $|w|\ne0$, +|b010| implies $|h|\ne 0$, and |b001| implies $|v|\ne 0$. + +\readcode +@s XDIMEN symbol +@s xdimen symbol +@s xdimen_node symbol +@s H symbol +@s V symbol +@<symbols@>= +%token XDIMEN "xdimen" +%token H "h" +%token V "v" +%type <xd> xdimen +@ +@<scanning rules@>= +::@=xdimen@> :< return XDIMEN; >: +::@=h@> :< return H; >: +::@=v@> :< return V; >: +@ + + +@<parsing rules@>= +xdimen: dimension number H number V { $$.w=$1; @+$$.h=$2; @+$$.v=$4; } + | dimension number H { $$.w=$1; @+$$.h=$2; @+$$.v=0.0; } + | dimension number V { $$.w=$1; @+$$.h=0.0; @+$$.v=$2; } + | dimension { $$.w=$1; @+$$.h=0.0; @+$$.v=0.0; }; + + + +xdimen_node: start XDIMEN xdimen END { hput_tags($1,hput_xdimen(&($3))); }; +@ + +\writecode +@<write functions@>= +void hwrite_xdimen(xdimen_t *x) +{ hwrite_dimension(x->w); + if (x->h!=0.0) {hwrite_float64(x->h); @+hwritec('h');@+} + if (x->v!=0.0) {hwrite_float64(x->v); @+hwritec('v');@+} +} + +void hwrite_xdimen_node(xdimen_t *x) +{ hwrite_start(); hwritef("xdimen"); hwrite_xdimen(x); hwrite_end();} +@ + +\getcode + +@<get macros@>= +#define @[HGET_XDIMEN(I,X)@] \ + if((I)&b100) HGET32((X).w);@+ else (X).w=0;\ + if((I)&b010) (X).h=hget_float32(); @+ else (X).h=0.0;\ + if((I)&b001) (X).v=hget_float32(); @+else (X).v=0.0; +@ + +@<get functions@>= +void hget_xdimen(uint8_t a, xdimen_t *x) +{ switch(a) + { + case TAG(xdimen_kind,b001): HGET_XDIMEN(b001,*x);@+break; + case TAG(xdimen_kind,b010): HGET_XDIMEN(b010,*x);@+break; + case TAG(xdimen_kind,b011): HGET_XDIMEN(b011,*x);@+break; + case TAG(xdimen_kind,b100): HGET_XDIMEN(b100,*x);@+break; + case TAG(xdimen_kind,b101): HGET_XDIMEN(b101,*x);@+break; + case TAG(xdimen_kind,b110): HGET_XDIMEN(b110,*x);@+break; + case TAG(xdimen_kind,b111): HGET_XDIMEN(b111,*x);@+break; + default: + QUIT("Extent expected got [%s,%d]",NAME(a),INFO(a)); + } + } +@ + +Note that the info value |b000|, usually indicating a reference, +is not supported for extended dimensions. +Most nodes that need an extended dimension offer the opportunity to give +a reference directly without the start and end byte. An exception is the glue node, +but glue nodes that need an extended width are rare. + +@<get functions@>= +void hget_xdimen_node(xdimen_t *x) +{ @<read the start byte |a|@>@; + if (KIND(a)==xdimen_kind) + hget_xdimen(a,x); + else + QUIT("Extent expected at 0x%x got %s",node_pos,NAME(a)); + @<read and check the end byte |z|@>@; +} +@ + + + +\putcode +@<put functions@>= +uint8_t hput_xdimen(xdimen_t *x) +{ info_t info=b000; + if (x->w==0 && x->h==0.0 && x->v==0.0){ HPUT32(0); @+info|=b100; @+} + else + { if (x->w!=0) { HPUT32(x->w); @+info|=b100; @+} + if (x->h!=0.0) { hput_float32(x->h); @+info|=b010; @+} + if (x->v!=0.0) { hput_float32(x->v); @+info|=b001; @+} + } + return TAG(xdimen_kind,info); +} +void hput_xdimen_node(xdimen_t *x) +{ uint32_t p=hpos++-hstart; + hput_tags(p, hput_xdimen(x)); +} + + +@ + + + +\subsection{Stretch and Shrink}\label{stretch} +In section~\secref{glue}, we will consider glue\index{glue} which +is something that can stretch and shrink. +The stretchability\index{stretchability} and shrinkability\index{shrinkability} of the +glue can be given in ``\.{pt}'' like a dimension, +but there are three more units: \.{fil}, \.{fill}, and \.{filll}. +A glue with a stretchability of $1\,\hbox{\tt fil}$ will stretch infinitely more +than a glue with a stretchability of $1\,\hbox{\tt pt}$. So if you stretch both glues +together, the first glue will do all the stretching and the latter will not stretch +at all. The ``\.{fil}'' glue has simply a higher order of infinity. +You might guess that ``\.{fill}'' glue and ``\.{filll}'' glue have even higher +orders of infinite stretchability. +The order of infinity is 0 for \.{pt}, 1 for \.{fil}, 2 for \.{fill}, and 3 for \.{filll}. + +The internal representation of a stretch is a variable of type |stretch_t|. +It stores the floating point value and the order of infinity separate as a |float64_t| and a |uint8_t|. + + +The short format tries to be space efficient and because it is not necessary to give the +stretchability with a precision exceeding about six decimal digits, +we use a single 32 bit floating point value. +To write a |float32_t| value and an order value as one 32 bit value, +we round the two lowest bit of the |float32_t| variable to zero +using ``round to even'' and store the order of infinity in these bits. +We define a union type \&{stch\_t} to simplify conversion. + +@<hint basic types@>= +typedef enum { @+ normal_o=0, fil_o=1, fill_o=2, filll_o=3@+} order_t; +typedef struct {@+ float64_t f;@+ order_t o; @+} stretch_t; +typedef union {@+float32_t f; @+ uint32_t u; @+} stch_t; +@ + +\putcode +@<put functions@>= +void hput_stretch(stretch_t *s) +{ uint32_t mantissa, lowbits, sign, exponent; + stch_t st; + st.f=s->f; + DBG(DBGFLOAT,"joining %f->%f(0x%X),%d:",s->f,st.f,st.u,s->o); + mantissa = st.u &(((uint32_t)1<<FLT_M_BITS)-1); + lowbits = mantissa&0x7; /* lowest 3 bits */ + exponent=(st.u>>FLT_M_BITS)&(((uint32_t)1<<FLT_E_BITS)-1); + sign=st.u & ((uint32_t)1<<(FLT_E_BITS+FLT_M_BITS)); + DBG(DBGFLOAT,"s=%d e=0x%x m=0x%x",sign, exponent, mantissa); + switch (lowbits) /* round to even */ + { @+case 0: break; /* no change */ + case 1: mantissa = mantissa -1; @+break;/* round down */ + case 2: mantissa = mantissa -2; @+break;/* round down to even */ + case 3: mantissa = mantissa +1; @+break; /* round up */ + case 4: break; /* no change */ + case 5: mantissa = mantissa -1; @+break;/* round down */ + case 6: mantissa = mantissa +1; /* round up to even, fall through */ + case 7: mantissa = mantissa +1; /* round up to even */ + if (mantissa >= ((uint32_t)1<<FLT_M_BITS))@/ + {exponent++; /* adjust exponent */ + RNG("Float32 exponent",exponent,1,2*FLT_EXCESS); + @+mantissa=mantissa>>1; + } + break; + } + DBG(DBGFLOAT," round s=%d e=0x%x m=0x%x",sign, exponent, mantissa); + st.u=sign| (exponent<<FLT_M_BITS) | mantissa | s->o; + DBG(DBGFLOAT,"float %f hex 0x%x\n",st.f, st.u); + HPUT32(st.u); +} +@ + +\getcode +@<get macros@>= +#define @[HGET_STRETCH(S)@] { stch_t st; @+ HGET32(st.u);@+ S.o=st.u&3; st.u&=~3; S.f=st.f; @+} +@ + +\readcode +@s FIL symbol +@s FILL symbol +@s FILLL symbol +@s order symbol + +@<symbols@>= +%token FIL "fil" +%token FILL "fill" +%token FILLL "filll" +%type <st> stretch +%type <o> order +@ + +@<scanning rules@>= +::@=fil@> :< return FIL; >: +::@=fill@> :< return FILL; >: +::@=filll@> :< return FILLL; >: +@ + +@s stretch symbol +@s stretch_t int +@<parsing rules@>= + +order: PT {$$=normal_o;} | FIL {$$=fil_o;} @+| FILL {$$=fill_o;} @+| FILLL {$$=filll_o;}; + +stretch: number order { $$.f=$1; $$.o=$2; }; +@ + +\writecode + +@<write functions@>= +void hwrite_order(order_t o) +{ switch (o) + { case normal_o: hwritef("pt"); @+break; + case fil_o: hwritef("fil"); @+break; + case fill_o: hwritef("fill"); @+break; + case filll_o: hwritef("filll"); @+break; + default: QUIT("Illegal order %d",o); @+ break; + } +} + +void hwrite_stretch(stretch_t *s) +{ hwrite_float64(s->f); + hwrite_order(s->o); +} +@ + +\section{Simple Nodes}\hascode +\label{simple} +\subsection{Penalties} +Penalties\index{penalty} are very simple nodes. They specify the cost of breaking a +line or page at the present position. For the internal representation +we use an |int32_t|. The full range of integers is, however, not +used. Instead penalties must be between -20000 and +20000. +(\TeX\ specifies a range of -10000 to +10000, but plain \TeX\ uses the value -20000 +when it defines the supereject control sequence.) +The more general node is called an integer node; +it shares the same kind-value |int_kind=penalty_kind| +but allows the full range of values. +The info value of a penalty node is 1 or 2 and indicates the number of bytes +used to store the integer. The info value 4 can be used for general +integers (see section~\secref{definitions}) that need four byte of storage. + +\readcode +@s PENALTY symbol +@s INTEGER symbol +@s penalty symbol +@<symbols@>= +%token PENALTY "penalty" +%token INTEGER "int" +%type <i> penalty +@ + +@<scanning rules@>= +::@=penalty@> :< return PENALTY; >: +::@=int@> :< return INTEGER; >: +@ + +@<parsing rules@>= +penalty: integer {RNG("Penalty",$1,-20000,+20000);$$=$1;}; +content_node: start PENALTY penalty END { hput_tags($1,hput_int($3));@+}; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@>case TAG(penalty_kind,1): @+{int32_t p;@+ HGET_PENALTY(1,p);@+} @+break; +case TAG(penalty_kind,2): @+{int32_t p;@+ HGET_PENALTY(2,p);@+} @+break; +@ + +@<get macros@>= +#define @[HGET_PENALTY(I,P)@] \ +if (I==1) {int8_t n=HGET8; @+P=n;@+ } \ +else {int16_t n;@+ HGET16(n);@+RNG("Penalty",n,-20000,+20000); @+ P=n; @+}\ +hwrite_signed(P); +@ + +\putcode +@<put functions@>= +uint8_t hput_int(int32_t n) +{ info_t info; + if (n>=0) @/ + { @+if (n<0x80) { @+HPUT8(n); @+info=1;@+ } + else if (n<0x8000) {@+ HPUT16(n);@+ info=2;@+ } + else {@+ HPUT32(n);@+ info=4;@+ } + } + else@/ + {@+ if (n>=-0x80) {@+ HPUT8(n);@+ info=1;@+ } + else if (n>=-0x8000) {@+ HPUT16(n);@+ info=2;@+ } + else {@+ HPUT32(n);@+ info=4;@+ } + } + return TAG(int_kind,info); +} +@ + + + + +\subsection{Languages} +To render a \HINT\ file on screen, information about the language is not necessary. +Knowing the language is, however, very important for language translation and +text to speech conversion which makes texts accessible to the visually-impaired. +For this reason, \HINT\ offers the opportunity to add this information +and encourages authors to supply this information. + +Language information by itself is not sufficient to decode text. It must be supplemented +by information about the character encoding (see section~\secref{fonts}). + +To represent language information, the world wide web has set universally +accepted standards. The Internet Engineering Task Force IETF has defined tags for identifying +languages\cite{rfc5646}: short strings like ``en'' for English +or ``de'' for Deutsch, and longer ones like ``sl-IT-nedis'', for the specific variant of +the Nadiza dialect of Slovenian that is spoken in Italy. +We assume that any \HINT\ file +will contain only a small number of different languages and all language nodes can be +encoded using a reference to a predefined node from the +definition section (see section~\secref{reference}). +In the definition section, a language node will just +contain the language tag as given in~\cite{iana:language} (see section~\secref{definitions}). + +\readcode +@s LANGUAGE symbol +@s language symbol + +@<symbols@>= +%token LANGUAGE "language" +@ + +@<scanning rules@>= +::@=language@> :< return LANGUAGE; >: +@ + +When encoding language nodes in the short format, +we use the info value |b000| for language nodes in the definition section +and for language nodes in the content section that contain just a one-byte +reference (see section~\secref{reference}). +We use the info value |1| to |7| as a shorthand for +the references {\tt *0} and {\tt *6} to the predefined language nodes. + + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} +@<cases to get content@>= +@t\1\kern1em@>case TAG(language_kind,1): REF(language_kind,0); @+hwrite_ref(0); @+break; +case TAG(language_kind,2): REF(language_kind,1); @+hwrite_ref(1); @+break; +case TAG(language_kind,3): REF(language_kind,2); @+hwrite_ref(2); @+break; +case TAG(language_kind,4): REF(language_kind,3); @+hwrite_ref(3); @+break; +case TAG(language_kind,5): REF(language_kind,4); @+hwrite_ref(4); @+break; +case TAG(language_kind,6): REF(language_kind,5); @+hwrite_ref(5); @+break; +case TAG(language_kind,7): REF(language_kind,6); @+hwrite_ref(6); @+break; +@ + +\putcode +@<put functions@>= +uint8_t hput_language(uint8_t n) +{ if (n<7) return TAG(language_kind,n+1); + HPUT8(n); return TAG(language_kind,0); +} +@ + + + +\subsection{Rules} +Rules\index{rule} are simply black rectangles having a height, a depth, and a +width. All of these dimensions can also be negative but a rule will +not be visible unless its width is positive and its height plus depth +is positive. + +As a specialty, rules can have ``running dimensions''\index{running dimension}. If any of the +three dimensions is a running dimension, its actual value will be +determined by running the rule up to the boundary of the innermost +enclosing box. The width is never running in an horizontal\index{horizontal list} list; the +height and depth are never running in a vertical\index{vertical list} list. In the long +format, we use a vertical bar ``{\tt \VB}'' or a horizontal bar +``{\tt \_}'' (underscore character) to indicate a running +dimension. Of course the vertical bar is meant to indicate a running +height or depth while the horizontal bar stands for a running +width. The parser, however, makes no distinction between the two and +you can use either of them. In the short format, we follow \TeX\ and +implement a running dimension by using the special value +$-2^{30}=|0xC0000000|$. + + +@<hint macros@>= +#define RUNNING_DIMEN 0xC0000000 +@ + +It could have been possible to allow extended dimensions in a rule node, +but in most circumstances, the mechanism of running dimensions is sufficient +and simpler to use. If a rule is needed that requires an extended dimension as +its length, it is always possible to put it inside a suitable box and use a +running dimension. + + +To make the short format encoding more compact, the first info bit +|b100| will be zero to indicate a running height, bit |b010| will be +zero to indicate a running depth, and bit |b001| will be zero to +indicate a running width. + +Because leaders\index{leaders} (see section~\secref{leaders}) may contain a rule +node, we also provide functions to read and write a complete rule +node. While parsing the symbol ``{\sl rule\/}'' will just initialize a variable of type +\&{rule\_t} (the writing is done with a separate routine), +parsing a {\sl rule\_node\/} will always include writing it. + +% Currently no predefined rules. +%Further, a {\sl rule\_node} will permit the +%use of a predefined rule (see section~\secref{reference}), + + +@<hint types@>= +typedef struct {@+ +dimen_t h,d,w; @+ +} rule_t; +@ + +\readcode +@s RULE symbol +@s RUNNING symbol +@s rule_dimension symbol +@s rule symbol +@s rule_node symbol +@<symbols@>= +%token RULE "rule" +%token RUNNING "|" +%type <d> rule_dimension +%type <r> rule +@ + +@<scanning rules@>= +::@=rule@> :< return RULE; >: +::@="|"@> :< return RUNNING; >: +::@="_"@> :< return RUNNING; >: +@ + +@<parsing rules@>= +rule_dimension: dimension@+ | RUNNING {$$=RUNNING_DIMEN;}; +rule: rule_dimension rule_dimension rule_dimension @/ + { $$.h=$1; @+ $$.d=$2; @+ $$.w=$3; + if ($3==RUNNING_DIMEN && ($1==RUNNING_DIMEN || $2==RUNNING_DIMEN)) + QUIT("Incompatible running dimensions 0x%x 0x%x 0x%x",@|$1,$2,$3); }; +rule_node: start RULE rule END { hput_tags($1,hput_rule(&($3))); }; +content_node: rule_node; +@ + +\writecode +@<write functions@>= +static void hwrite_rule_dimension(dimen_t d, char c) +{ @+if (d==RUNNING_DIMEN) hwritef(" %c",c); + else hwrite_dimension(d); +} + +void hwrite_rule(rule_t *r) +{ @+hwrite_rule_dimension(r->h,'|'); + hwrite_rule_dimension(r->d,'|'); + hwrite_rule_dimension(r->w,'_'); +} +@ +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(rule_kind,b011): {rule_t r;@+ HGET_RULE(b011,r); @+hwrite_rule(&(r));@+ } @+break; +case TAG(rule_kind,b101): {rule_t r;@+ HGET_RULE(b101,r); @+hwrite_rule(&(r));@+ } @+break; +case TAG(rule_kind,b001): {rule_t r;@+ HGET_RULE(b001,r); @+hwrite_rule(&(r));@+ } @+break; +case TAG(rule_kind,b110): {rule_t r;@+ HGET_RULE(b110,r); @+hwrite_rule(&(r));@+ } @+break; +case TAG(rule_kind,b111): {rule_t r;@+ HGET_RULE(b111,r); @+hwrite_rule(&(r));@+ } @+break; +@ + +@<get macros@>= +#define @[HGET_RULE(I,R)@]@/\ +if ((I)&b100) HGET32((R).h); @+else (R).h=RUNNING_DIMEN;\ +if ((I)&b010) HGET32((R).d); @+else (R).d=RUNNING_DIMEN;\ +if ((I)&b001) HGET32((R).w); @+else (R).w=RUNNING_DIMEN; +@ + +@<get functions@>= +void hget_rule_node(void) +{ @<read the start byte |a|@>@; + if (KIND(a)==rule_kind) @/ + { @+rule_t r; @+HGET_RULE(INFO(a),r); @/ + hwrite_start();@+ hwritef("rule"); @+hwrite_rule(&r); @+hwrite_end(); + } + else + QUIT("Rule expected at 0x%x got %s",node_pos,NAME(a)); + @<read and check the end byte |z|@>@; +} +@ + +\putcode +@<put functions@>= +uint8_t hput_rule(rule_t *r) +{ info_t info=b000; + if (r->h!=RUNNING_DIMEN) { HPUT32(r->h); @+info|=b100; @+} + if (r->d!=RUNNING_DIMEN) { HPUT32(r->d); @+info|=b010; @+} + if (r->w!=RUNNING_DIMEN) { HPUT32(r->w); @+info|=b001; @+} + return TAG(rule_kind,info); +} +@ + + +\subsection{Kerns} +A kern\index{kern} is a bit of white space with a certain length. If the kern is part of a +horizontal list, the length is measured in the horizontal direction, +if it is part of a vertical list, it is measured in the vertical +direction. The length of a kern is mostly given as a dimension +but provisions are made to use extended dimensions as well. + +The typical +use of a kern is its insertion between two characters to make the natural +distance between them a bit wider or smaller. In the latter case, the kern +has a negative length. The typographic optimization just described is called +``kerning'' and has given the kern node its name. +Kerns inserted from font information or math mode calculations are normal kerns, +while kerns inserted from \TeX's {\tt \BS kern} or {\tt \BS/} +commands are explicit kerns. +Kern nodes do not disappear at a line break unless they are explicit\index{explicit kern}. + +In the long format, explicit kerns are marked with an ``!'' sign +and in the short format with the |b100| info bit. +The two low order info bits are: 0 for a reference to a dimension, 1 for a reference to +an extended dimension, 2 for an immediate dimension, and 3 for an immediate extended dimension node. +To distinguish in the long format between a reference to a dimension and a reference to an extended dimension, +the latter is prefixed with the keyword ``{\tt xdimen}'' (see section~\secref{reference}). + +@<hint types@>= +typedef struct {@+ +bool x;@+ +xdimen_t d;@+ +} kern_t; +@ + +\readcode +@s KERN symbol +@s EXPLICIT symbol +@s kern symbol +@s explicit symbol +@<symbols@>= +%token KERN "kern" +%token EXPLICIT "!" +%type <b> explicit +%type <kt> kern +@ + +@<scanning rules@>= +::@=kern@> :< return KERN; >: +::@=!@> :< return EXPLICIT; >: +@ + +@<parsing rules@>= +explicit: {$$=false;} @+| EXPLICIT {$$=true;}; +kern: explicit xdimen {$$.x=$1; $$.d=$2;}; +content_node: start KERN kern END { hput_tags($1,hput_kern(&($3)));} +@ + +\writecode +@<write functions@>= +void hwrite_explicit(bool x) +{ @+if (x) hwritef(" !"); @+} + +void hwrite_kern(kern_t *k) +{ @+hwrite_explicit(k->x); + if (k->d.h==0.0 && k->d.v==0.0 && k->d.w==0) hwrite_ref(zero_dimen_no); + else hwrite_xdimen(&(k->d)); +} +@ + + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(kern_kind,b010): @+ {@+kern_t k; @+HGET_KERN(b010,k);@+ } @+break; +case TAG(kern_kind,b011): @+ {@+kern_t k; @+HGET_KERN(b011,k);@+ } @+break; +case TAG(kern_kind,b110): @+ {@+kern_t k; @+HGET_KERN(b110,k);@+ } @+break; +case TAG(kern_kind,b111): @+ {@+kern_t k; @+HGET_KERN(b111,k);@+ } @+break; +@ + +@<get macros@>= +#define @[HGET_KERN(I,K)@] \ +K.x=(I)&b100;\ +if (((I)&b011)==2) {HGET32(K.d.w);@+ K.d.h=K.d.v=0.0;@+}\ +else if (((I)&b011)==3) hget_xdimen_node(&(K.d));\ +hwrite_kern(&k); +@ + +\putcode +@<put functions@>= +uint8_t hput_kern(kern_t *k) +{ info_t info; + if (k->x) info=b100; @+else info=b000; + if (k->d.h==0.0 && k->d.v==0.0) + { if (k->d.w==0) HPUT8(zero_dimen_no); + else {HPUT32(k->d.w); info=info|2;@+} + } + else {hput_xdimen_node(&(k->d));info=info|3;@+} + return TAG(kern_kind,info); +} +@ + + + +\subsection{Glue}\label{glue} + +%Glue considerations + +%So what are the cases: +%\itemize +%\item reference to a dimen (common) +%\item reference to a xdimen +%\item reference to a dimen plus and minus +%\item reference to a xdimen plus and minus +%\item reference to a dimen plus +%\item reference to a xdimen plus +%\item reference to a dimen minus +%\item reference to a xdimen minus +%\item dimen +%\item xdimen +%\item dimen plus and minus +%\item xdimen plus and minus (covers all other cases) +%\item dimen plus +%\item xdimen plus +%\item dimen minus +%\item xdimen minus +%\item plus and minus +%\item plus +%\item minus +%\item zero glue (rare, can be replaced by a reference to the zero glue) +%\item reference to a predefined glue (common) +%\enditemize +%This is a total of 21 cases. Can we use the info bits to specify 7 common +%cases and one catch all? First the use of an extended dimension in a glue +%is probably not very common. More typically is the use of a fill glue +%that extends to the boundaries of the enclosing box. + +%Here is the statistics for ctex: +%total 58937 glue entries +%total 49 defined glues (so 200 still available) +%There are three font specific glues defined for each font used in texts. +%The explicit glue nodes are the following: +%\itemize +%\item 35\% is predefined zero glue +%\item 30\% are 39 other predefined glue most of them less than 1% +%\item 8\% (4839) is one glue with 25pt pure stretch with order 0 +%\item 25\% (14746) is one glue with 100pt stretch and 10pt shrink with order 0 +%\item 2\% (1096) is one glue with 10pt no stretch and shrink +%\item 0\% (13) are 7 different glues with no stretch and shrink +%\item 0\% (3) different glues with width!=0 and some stretch of order 0 +%\item 0\% (27) 20 different glues with stretch and shrink +%\enditemize + +%Some more glue with 1fil is insider 55 leaders +%one vset has an extent 1 no stretch and shrink +%56 hset specify an extent 2 and 1 fil stretch + + +We have seen in section~\secref{stretch} how to deal with +stretchability\index{stretchability} and +shrinkability\index{shrinkability} and we will need this now. +Glue\index{glue} has a natural width---which in general can be an +extended dimension---and in addition it can stretch and shrink. It +might have been possible to allow an extended dimension also for the +stretch\-ability or shrink\-ability of a glue, but this seems of +little practical relevance and so simplicity won over generality. +Even with that restriction, it is an understatement to regard glue +nodes as "simple" nodes. +%, and we could equally well list them in +%section~\secref{composite} as composite nodes. + +To use the info bits in the short format wisely, I collected some +statistical data using the \TeX book as an example. It turns out that +about 99\% of all the 58937 glue nodes (not counting the interword +glues used inside texts) could be covered with only 43 predefined +glues. So this is by far the most common case; we reserve the info +value |b000| to cover it and postpone the description of such glue +nodes until we describe references in section~\secref{reference}. + +We expect the remaining cases to contribute not too much to the file +size, and hence, simplicity is a more important aspect than efficiency +when allocating the remaining info values. + +Looking at the glues in more detail, we find that the most common +cases are those where either one, two, or all three glue components +are zero. We use the two lowest bits to indicate the presence of a +nonzero stretchability or shrinkability and reserve the info values +|b001|, |b010|, and |b011| for those cases where the width of the glue +is zero. The zero glue, where all components are zero, is defined as +a fixed, predefined glue instead of reserving a special info value for +it. The cost of one extra byte when encoding it seems not too high a +price to pay. After reserving the info value |b111| for the most +general case of a glue, we have only three more info values left: +|b100|, |b101|, and |b110|. Keeping things simple implies using the +two lowest info bits---as before---to indicate a nonzero +stretchability or shrinkability. For the width, three choices remain: +using a reference to a dimension, using a reference to an extended +dimension, or using an immediate value. Since references to glues are +already supported, an immediate width seems best for glues that are +not frequently reused, avoiding the overhead of references. + +% It also makes parsing simpler because we avoid the confusion +% between references to dimensions +% and references to glues and references to extended dimensions. + +Here is a summary of the info bits and the implied layout +of glue nodes in the short format: +\itemize +\item |b000|: reference to a predefined glue +\item |b001|: zero width and nonzero shrinkability +\item |b010|: zero width and nonzero stretchability +\item |b011|: zero width and nonzero stretchability and shrinkability +\item |b100|: nonzero width +\item |b101|: nonzero width and nonzero shrinkability +\item |b110|: nonzero width and nonzero stretchability +\item |b111|: extended dimension and nonzero stretchability and shrinkability +\enditemize + + +@<hint basic types@>= +typedef struct {@+ +xdimen_t w; @+ +stretch_t p, m;@+ +} glue_t; +@ + + +To test for a zero glue, +we implement a macro: +@<hint macros@>= +#define @[ZERO_GLUE(G)@] ((G).w.w==0 && (G).w.h==0.0 && (G).w.v==0.0 && (G).p.f==0.0 && (G).m.f==0.0) +@ + +Because other nodes (leaders, baselines, and fonts) +contain glue nodes as parameters, we provide functions +to read and write a complete glue node in the same way as we did +for rule nodes. +Further, such an internal {\sl glue\_node\/} has the special property that +in the short format a node for the zero glue might be omitted entirely. + +\readcode +@s GLUE symbol +@s glue symbol +@s glue_node symbol +@s PLUS symbol +@s MINUS symbol +@s plus symbol +@s minus symbol + +@<symbols@>= +%token GLUE "glue" +%token PLUS "plus" +%token MINUS "minus" +%type <g> glue +%type <b> glue_node +%type <st> plus minus +@ + +@<scanning rules@>= +::@=glue@> :< return GLUE; >: +::@=plus@> :< return PLUS; >: +::@=minus@> :< return MINUS; >: +@ + +@<parsing rules@>= +plus: { $$.f=0.0; $$.o=0; } | PLUS stretch {$$=$2;}; +minus: { $$.f=0.0; $$.o=0; } | MINUS stretch {$$=$2;}; +glue: xdimen plus minus {$$.w=$1; $$.p=$2; $$.m=$3; }; +content_node: start GLUE glue END {if (ZERO_GLUE($3)) {HPUT8(zero_skip_no); + hput_tags($1,TAG(glue_kind,0)); } else hput_tags($1,hput_glue(&($3))); }; +glue_node: start GLUE glue END @/ + {@+ if (ZERO_GLUE($3)) { hpos--; $$=false;@+}@/ + else { hput_tags($1,hput_glue(&($3))); $$=true;@+}@+ }; +@ + +\writecode +@<write functions@>= +void hwrite_plus(stretch_t *p) +{ @+if (p->f!=0.0) { hwritef(" plus");@+hwrite_stretch(p); @+} +} +void hwrite_minus(stretch_t *m) +{@+ if (m->f!=0.0) { hwritef(" minus");@+hwrite_stretch(m); @+} +} + +void hwrite_glue(glue_t *g) +{ hwrite_xdimen(&(g->w)); @+ + hwrite_plus(&g->p); @+hwrite_minus(&g->m); +} + +void hwrite_ref_node(kind_t k, uint8_t n); +void hwrite_glue_node(glue_t *g) +{@+ + if (ZERO_GLUE(*g)) hwrite_ref_node(glue_kind,zero_skip_no); + else @+{ hwrite_start(); @+hwritef("glue"); @+hwrite_glue(g); @+hwrite_end();@+} +} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(glue_kind,b001): { glue_t g;@+ HGET_GLUE(b001,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b010): { glue_t g;@+ HGET_GLUE(b010,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b011): { glue_t g;@+ HGET_GLUE(b011,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b100): { glue_t g;@+ HGET_GLUE(b100,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b101): { glue_t g;@+ HGET_GLUE(b101,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b110): { glue_t g;@+ HGET_GLUE(b110,g);@+ hwrite_glue(&g);@+}@+break; +case TAG(glue_kind,b111): { glue_t g;@+ HGET_GLUE(b111,g);@+ hwrite_glue(&g);@+}@+break; +@ + +@<get macros@>= +#define @[HGET_GLUE(I,G)@] {\ + if((I)!=b111) { if ((I)&b100) HGET32((G).w.w);@+ else (G).w.w=0;}\ + if((I)&b010) HGET_STRETCH((G).p) @+else (G).p.f=0.0, (G).p.o=0;\ + if((I)&b001) HGET_STRETCH((G).m) @+else (G).m.f=0.0, (G).m.o=0;\ + if((I)==b111) hget_xdimen_node(&((G).w)); else (G).w.h=(G).w.v=0.0;@+} +@ + +The |hget_glue_node| can cope with a glue node that is omitted and +will supply a zero glue instead. + +@<get functions@>= +void hget_glue_node(void) +{ @<read the start byte |a|@>@; + if (KIND(a)!=glue_kind) + {@+ hpos--; hwrite_ref_node(glue_kind,zero_skip_no);@+return; @+} + if (INFO(a)==b000) + { uint8_t n=HGET8;@+ REF(glue_kind,n);@+hwrite_ref_node(glue_kind,n); @+} + else + { @+glue_t g; @+HGET_GLUE(INFO(a),g);@+ hwrite_glue_node(&g);@+} + @<read and check the end byte |z|@>@; +} +@ + + +\putcode +@<put functions@>= +uint8_t hput_glue(glue_t *g) +{ info_t info=b000; + if (ZERO_GLUE(*g)) { HPUT8(zero_skip_no); @+ info=b000; } + else if ( (g->w.w==0 && g->w.h==0.0 && g->w.v==0.0)) + { if (g->p.f!=0.0) { hput_stretch(&g->p); @+info|=b010; @+} + if (g->m.f!=0.0) { hput_stretch(&g->m); @+info|=b001; @+} + } + else if ( g->w.h==0.0 && g->w.v==0.0 && (g->p.f==0.0 || g->m.f==0.0)) + { HPUT32(g->w.w); @+ info=b100; + if (g->p.f!=0.0) { hput_stretch(&g->p); @+info|=b010; @+} + if (g->m.f!=0.0) { hput_stretch(&g->m); @+info|=b001; @+} + } + else@/ + { hput_stretch(&g->p);@+ hput_stretch(&g->m); + hput_xdimen_node(&(g->w)); + info=b111; + } + return TAG(glue_kind,info); +} +@ + +\section{Lists}\hascode\label{lists} +When a node contains multiple other nodes, we package these nodes into +a list\index{list} node. It is important to note that list nodes +never occur as individual nodes, they only occur as parts of other +nodes. In total, we have three different types of lists: plain lists +that use the kind-value |list_kind|, text\index{text} lists that use +the kind-value |text_kind|, and parameter\index{parameter} lists that use the +kind-value |param_kind|. A description of the first two types of +lists follows here. Parameter lists are described in section~\secref{paramlist}. + +Because lists are of variable size, it is not possible in the short +format to tell from the kind and info bits of a tag byte the size of +the list node. So advancing from the beginning of a list node to the +next node after the list is not as simple as usual. To solve this +problem, we store the size of the list immediately after the start +byte and before the end byte. Alternatively we could require programs +to traverse the entire list. The latter solution is more compact but +inefficient for list with many nodes; our solution will cost some +extra bytes, but the amount of extra bytes will only grow +logarithmically with the size of the \HINT\ file. It would be +possible to allow both methods so that a \HINT\ file could balance +size and time trade-offs by making small lists---where the size can be +determined easily by reading the entire list---without size +information and making large lists with size information so that they +can be skipped easily without reading them. But the added complexity +seems too high a price to pay. + + +Now consider the problem of reading a content stream starting at an arbitrary +position $i$ in the middle of the stream. This situation occurs +naturally when resynchronizing\index{resynchronization} a content stream after +an error has been detected, but implementing links poses a similar problem. +We can inspect the byte at position $i$ and see +if it is a valid tag. If yes, we are faced with the problem of +verifying that this is not a mere coincidence. +So we determine the size $s$ of the node. If the byte in question is a start byte, +we should find a matching byte $s$ bytes later in the stream; if it is an end byte, +we should find the matching byte $s$ bytes earlier in the stream; if we +find no matching byte, this was neither a start nor an end byte. +If we find exactly one matching byte, we can be quite confident (error +probability 1/256 if assuming equal probability of all byte values) +that we have found a tag, and we know whether +it is the beginning or the end tag. If we find two matching byte, we +have most likely the start or the end of a node, but we do not know which +of the two. To find out which of the two possibilities is true +or to reduce the probability of an error, we can +check the start and end byte of the node immediately preceding a start byte or +immediately following an end byte in a similar way. +By testing two more byte, this additional check will reduce the error +probability further to $1/2^{24}$ (under the same assumption as before). So +checking more nodes is rarely necessary. This whole schema +would, however, not work if we happen to find a tag byte that indicated +either the begin or the end of a list without specifying the size +of the list. Sure, we can verify the bytes before and after it to +find out whether the byte following it is the begin of a node and the +byte preceding it is the end of a node, but we still don't know if the +byte itself starts a node list or ends a node list. Even reading along +in either direction until finding a matching tag will not answer the +question. The situation is better if we specify a +size: we can read the suspected size after or before the tag and check if we +find a matching tag and size at the position indicated. +In the short format, we use the |info| value to indicate the number of +byte used to store the list size: A list with $0<|info|\le 5$ +uses $|info|-1$ byte to store the size. +The info value zero is reserved for references to predefined lists +(which are currently not implemented). + +Storing the list size immediately preceding the end tag creates a new +problem: If we try to recover from an error, we might not know the +size of the list and searching for the end of a list, we might be +unable to tell the difference between the bytes that encode the list +size and the start tag of a possible next node. If we parse the +content backward, the problem is completely symmetric. + +To solve the problem, we insert an additional byte immediately before +the final size and after the initial size marking the size boundary. +We choose the byte values |0xFF|, |0xFE|, |0xFD|, and |0xFC| which can +not be confused with valid tag bytes and indicate that the size is +stored using 1, 2, 3, or 4 byte respectively. Under regular +circumstances, these bytes are simply skipped. When searching for the +list end (or start) these bytes would correspond to +|TAG(penalty_kind,i)| with $7 \ge \hbox{|i|} \ge 4$ and can not be +confused with valid penalty nodes which use only the info values 0, 1, +and~2. An empty list uses the info value 1 and has neither a size bytes +nor boundary bytes; it consists only of the two tags. + +We are a bit lazy when it comes to the internal representation of a list. +Since we need the representation as a short format byte sequence anyway, +it consists of the position |p| of the start of the byte sequence +combined with an integer |s| giving the size of the byte sequence. +If the list is empty, |s| is zero. + +@<hint types@>= +typedef struct {@+ +kind_t k; @+ +uint32_t p;@+ +uint32_t s;@+ +} list_t; +@ + +The major drawback of this choice of representation is that it ties +together the reading of the long format and the writing of the short +format; these are no longer independent. +So starting with the present section, we have to take the short format +representation of a node into account already when we parse the long +format representation. + +In the long format, we may start a list node with an +estimate\index{estimate} of the size needed to store the list in the +short format. We do not want to require the exact size because this +would make editing of long format \HINT\ files almost impossible. Of +course this makes it also impossible to derive the exact |s| value of +the internal representation from the long format +representation. Therefore we start by parsing the estimate of the list +size and use it to reserve the necessary number of byte to store the +size. Then we parse the |content_list|. As a side effect---and this +is an important point---this will write the list content in short +format into the output buffer. As mentioned above, whenever a node +contains a list, we need to consider this side effect when we give the +parsing rules. We will see examples for this in +section~\secref{composite}. + +The function |hput_list| will be called {\it after} the short format +of the list is written to the output. Before we pass the internal +representation of the list to the |hput_list| +function, we update |s| and |p|. Further, we pass the position in the stream where the +list size and its boundary mark is supposed to be. +Before |hput_list| is called, space for the tag, the size, and the boundary mark +is allocated based on the estimate. The function +|hsize_bytes| computes the number of byte required to store the list +size, and the function |hput_list_size| will later write the list +size. If the estimate turns out to be wrong, the list data can be moved +to make room for a larger or smaller size field. + + +If the long format does not specify a size estimate, a suitable default must be chosen. +A statistical analysis shows +% +%statistics about list sizes using my old prototype +% +%name type size_byte list_count total_size +%hello.hnt text 1 6 748 +% text 2 2 1967 +% list 1 65 3245 +% list 2 1 352 +%web2w.hnt text 1 1043 121925 +% text 2 1344 859070 +% list 1 19780 725514 +% list 2 487 199243 +%ctex.hnt text 1 9121 4241128 +% text 2 12329 7872687 +% text 3 1 75010 +% list 1 121557 4600743 +% list 2 222 147358 +% +that most plain lists need only a single byte to store the size; and even the +total amount of data contained in these lists exceeds the amount of data stored +in longer lists by a factor of about 3. Hence if we do not have an estimate, +we reserve only a single byte to store the size of a list. +The statistics looks different for lists stored as a text: The number of texts +that require two byte for the size is slightly larger than the number of texts that +need only one byte, and the total amount of data stored in these texts is larger +by a factor of 2 to 7 than the total amount of data found in all other texts. +Hence as a default, we reserve two byte to store the size for texts. + + +\subsection{Plain Lists}\label{plainlists} +Plain list nodes start and end with a tag of kind |list_kind|. + +Not uncommon are empty\index{empty list} lists; these are the only lists that can be +stored using $|info|=1$; such a list has zero bytes of size +information, and no boundary bytes either; implicitly its size is zero. +The |info| value 0 is not used since we do not use predefined plain lists. + +Writing the long format uses the fact that the function +|hget_content_node|, as implemented in the \.{stretch} program, will +output the node in the long format. + +\readcode +@s list symbol +@s content_list symbol +@s estimate symbol +@s position symbol + +@<symbols@>= +%type <l> list +%type <u> position content_list +@ + +@<parsing rules@>= +position: {$$=hpos-hstart;}; +content_list: @+ position @+ + | content_list content_node; +estimate: {hpos+=2; } @+ + | UNSIGNED {hpos+=hsize_bytes($1)+1; } ; +list: start estimate content_list END @/ + {@+$$.k=list_kind;@+ $$.p=$3; @+ $$.s=(hpos-hstart)-$3; + hput_tags($1,hput_list($1+1, &($$)));@+}; +@ + +\writecode +@<write functions@>= +void hwrite_list(list_t *l) +{ uint32_t h=hpos-hstart, e=hend-hstart; /* save |hpos| and |hend| */ + hpos=l->p+hstart;@+ hend=hpos+l->s; + if (l->k==list_kind ) @<write a list@>@; + else if (l->k==text_kind) @<write a text@>@; + else QUIT("List expected got %s", content_name[l->k]); + hpos=hstart+h;@+ hend=hstart+e; /* restore |hpos| and |hend| */ +} +@ + +@<write a list@>= +{@+if (l->s==0) hwritef(" <>");@/ + else@/ + {@+DBG(DBGNODE,"Write list at 0x%x size=%u\n", l->p, l->s); + @+hwrite_start();@+ + if (section_no==2) hwrite_label(); + if (l->s>0xFF) hwritef("%d",l->s); + while(hpos<hend) + hget_content_node(); + hwrite_end(); + } +} +@ +\getcode +@<shared get functions@>= +void hget_size_boundary(info_t info) +{ uint32_t n; + if (info<2) return; + n=HGET8; + if (n-1!=0x100-info) QUIT(@["Size boundary byte 0x%x with info value %d at " SIZE_F@], + n, info,hpos-hstart-1); +} + +uint32_t hget_list_size(info_t info) +{ uint32_t n=0; + if (info==1) return 0; + else if (info==2) n=HGET8; + else if (info==3) HGET16(n); + else if (info==4) HGET24(n); + else if (info==5) HGET32(n); + else QUIT("List info %d must be 1, 2, 3, 4, or 5",info); + return n; +} + +void hget_list(list_t *l) +{@+if (KIND(*hpos)!=list_kind && @/ + KIND(*hpos)!=text_kind &&@| KIND(*hpos)!=param_kind) @/ + QUIT("List expected at 0x%x", (uint32_t)(hpos-hstart)); + else + { + @<read the start byte |a|@>@; + l->k=KIND(a); + HGET_LIST(INFO(a),*l); + @<read and check the end byte |z|@>@; + DBG(DBGNODE,"Get list at 0x%x size=%u\n", l->p, l->s); + } +} +@ + +@<shared get macros@>= +#define @[HGET_LIST(I,L)@] \ + (L).s=hget_list_size(I); hget_size_boundary(I);\ + (L).p=hpos-hstart; \ + hpos=hpos+(L).s; hget_size_boundary(I);\ + { uint32_t s=hget_list_size(I); \ + if (s!=(L).s) \ + QUIT(@["List sizes at 0x%x and " SIZE_F " do not match 0x%x != 0x%x"@],node_pos+1,hpos-hstart-I-1,(L).s,s);} +@ + +\putcode + +@<put functions@>= +uint8_t hsize_bytes(uint32_t n) +{ @+if (n==0) return 0; + else if (n<0x100) return 1; + else if (n<0x10000) return 2; + else if (n<0x1000000) return 3; + else return 4; +} + +void hput_list_size(uint32_t n, int i) +{ @+if (i==0) ; + else if (i==1) HPUT8(n); + else if (i==2) HPUT16(n); + else if (i==3) HPUT24(n); + else HPUT32(n); +} + +uint8_t hput_list(uint32_t start_pos, list_t *l) +{ @+if (l->s==0) + { hpos=hstart+start_pos; return TAG(l->k,1);@+} + else@/ + { uint32_t list_end=hpos-hstart; + int i=l->p -start_pos-1; /* number of byte allocated for size */ + int j=hsize_bytes(l->s); /* number of byte needed for size */ + DBG(DBGNODE,"Put list at 0x%x size=%u\n", l->p, l->s); + if (i>j && l->s> 0x100) j=i; /* avoid moving large lists */ + if (i!=j)@/ + { int d= j-i; + DBG(DBGNODE,"Moving %u byte by %d\n", l->s,d); + if (d>0) HPUTX(d); + memmove(hstart+l->p+d,hstart+l->p,l->s); + @<adjust label positions after moving a list@>@; + l->p=l->p+d;@+ + list_end=list_end+d; + } + hpos=hstart+start_pos; @+ hput_list_size(l->s,j);@+ HPUT8(0x100-j); + hpos=hstart+list_end;@+ HPUT8(0x100-j);@+ hput_list_size(l->s,j); + return TAG(l->k,j+1); + } +} + +@ + + + +\subsection{Texts}\label{text} +A Text\index{text} is a list of nodes with a representation optimized +for character nodes. In the long format, a sequence of characters +like ``{\tt Hello}'' is written ``\.{<glyph 'H'} \.{*0>} \.{<glyph} \.{'e'} +\.{*0>} \.{<glyph 'l' *0>} \.{<glyph 'l' *0>} \.{<glyph 'o' *0>}'', and +even in the short format it requires 4 byte per character! As a text, +the same sequence is written ``{\tt\,"Hello"\,}'' in the long format and the +short format requires usually just 1 byte per character. Indeed +except the bytes with values from |0x00| to |0x20|, which are +considered control\index{control code} codes, all bytes and all +\hbox{UTF-8}\index{UTF8} multibyte sequences are simply considered +character\index{character code} codes. They are equivalent to a glyph +node in the ``current font''. The current\index{current font} +font\index{font} is font number 0 at the beginning of a text and it +can be changed using the control codes. We introduce the concept of a +``current font'' because we do not expect the font to change too +often, and it allows for a more compact representation if we do not +store the font with every character code. It has an important +disadvantage though: storing only font changes prevents us from +parsing a text backwards; we always have to start at the beginning of +the text, where the font is known to be font number~0. + +Defining a second format for encoding lists of nodes adds another +difficulty to the problem we had discussed at the beginning of +section~\secref{lists}. When we try to recover from an error and start +reading a content stream at an arbitrary position, the first thing we +need to find out is whether at this position we have the tag byte of +an ordinary node or whether we have a position inside a text. + +Inside a text, character nodes start with a byte in the range +|0x21|--|0xF7|. This is a wide range and it overlaps considerably with +the range of valid tag bytes. It is however possible to choose the +kind-values in such a way that the control codes do not overlap with +the valid tag bytes that start a node. For this reason, the values +|text_kind==0|, |list_kind==1|, |param_kind==2|, |xdimen_kind==3|, and +|adjust_kind==4| were chosen on page~\pageref{kinddef}. Texts, lists, +parameter lists, and extended dimensions occur only {\it inside} of +content nodes, but are not content nodes in their own right; so the +values |0x00| to |0x1F| are not used as tag bytes of content +nodes. The value |0x20| would, as a tag byte, indicate an adjust node +(|adjust_kind==4|) with info value zero. Because there are no +predefined adjustments, |0x20| is not used as a tag byte either. +(An alternative choice would be to use the kind value 4 for paragraph +nodes because there are no predefined paragraphs.) + +The largest byte that starts an UTF8 code is |0xF7|; hence, there are +eight possible control codes, from |0xF8| to |0xFF|, available. The +first three values |0xF8|, |0xF9|, and |0xFA| are actually used for +penalty nodes with info values, 0, 1, and 2. The last four |0xFC|, +|0xFD|, |0xFE|, and |0xFF| are used as boundary marks for the text +size and therefore we use only |0xFB| as control code. + +In the long format, we do not provide a syntax for specifying a size +estimate\index{estimate} as we did for plain lists, because we expect +text to be quite short. We allocate two byte for the size and hope +that this will prove to be sufficient most of the time. Further, we +will disallow the use of non-printable ASCII codes, because these +are---by definition---not very readable, and we will give special +meaning to some of the printable ASCII codes because we will need a +notation for the beginning and ending of a text, for nodes inside a +text, and the control codes. + +Here are the details: +\itemize + +\item In the long format, a text starts and ends with a +double\index{double quote} quote character ``{\tt "}''. In the short +format, texts are encoded similar to lists using the kind-value +|text_kind|. + +\item Arbitrary nodes can be embedded inside a text. In the long +format, they are enclosed in pointed brackets \.{<} \dots \.{>} as +usual. In the short format, an arbitrary node can follow the control +code $|txt_node|=|0x1E|$. Because text may occur in nodes, the scanner +needs to be able to parse texts nested inside nodes nested inside +nodes nested inside texts \dots\ To accomplish this, we use the +``stack'' option of \.{flex} and include the pushing and popping of the +stack in the macros |SCAN_START| and |SCAN_END|. + +\item The space\index{space character} character ``\.{\ }'' with ASCII +value |0x20| stands in both formats for the font specific interword +glue node (control code |txt_glue|). + +\item The hyphen\index{hyphen character} character ``\.{-}'' in the +long format and the control code $|txt_hyphen|=|0x1F|$ in the short +format stand for the font specific discretionary hyphenation node. + +\item In the long format, the backslash\index{backslash} character +``\.{\\}'' is used as an escape character. It is used to introduce +notations for control codes, as described below, and to access the +character codes of those ASCII characters that otherwise carry a +special meaning. For example ``{\tt \BS "}'' denotes the character code +of the double quote character ``{\tt "}''; and similarly ``\.{\\\\}'', +``\.{\\<}'', ``\.{\\>}'', ``\.{\\\ }'', and ``\.{\\-}'' denote the +character codes of ``\.{\\}'', ``\.{<}'', ``\.{>}'', ``\.{\ }'', and +``\.{-}'' respectively. + + +\item In the long format, a TAB-character (ASCII code +|0x09|)\index{tab character} is silently converted to a +space\index{space character} character (ASCII code |0x20|); +a NL-character\index{newline character} (ASCII code |0x0A|), together +with surrounding spaces, TAB-characters, +and CR-characters\index{carriage return character} (ASCII code |0x0D|), +is silently converted to a single space character. All other ASCII +characters in the range |0x00| to |0x1F| are not allowed inside a +text. This rule avoids the problems arising from ``invisible'' +characters embedded in a text and it allows to break texts into lines, +even with indentation\index{indentation}, at word boundaries. + +To allow breaking a text into lines without inserting spaces, a +NL-character together with surrounding spaces, TAB-characters, and +CR-characters is completely ignored if the whole group of spaces, +TAB-characters, CR-characters, and the NL-character is preceded by a +backslash character. + +For example, the text ``\.{"There\ is\ no\ more\ gas\ in\ the\ +tank."}''\hfil\break can be written as \medskip + +\qquad\vbox{\hsize=0.5\hsize\noindent +\.{"There\ is\ }\hfil\break +\.{\hbox to 2em {$\rightarrow$\hfill}no more g\\\ \ }\hfil\break +\.{\hbox to 2em {$\rightarrow$\hfill}as in the tank."} +}\hss + +To break long lines when writing a long format file, we use the +variable |txt_length| to keep track of the approximate length of the +current line. + +\item The control codes $|txt_font|=|0x00|$, |0x01|, |0x02|, \dots, +and |0x07| are used to change the current font to font +number 0, 1, 2, \dots, and 7. In the long format these control +codes are written \.{\\0}, \.{\\1}, \.{\\2}, \dots, and \.{\\7}. + +\item The control code $|txt_global|=|0x08|$ is followed by a second +parameter byte. If the value of the parameter byte is $n$, it will set +the current font to font number $n$. In the long format, the two byte +sequence is written ``\.{\\F}$n$\.{\\}'' where $n$ is the decimal +representation of the font number. + + +\item The control codes |0x09|, |0x0A|, |0x0B|, |0x0C|, |0x0E|, +|0x0E|, |0x0F|, and |0x10| are also followed by a second parameter +byte. They are used to reference the global definitions of +penalty\index{penalty}, kern\index{kern}, ligature\index{ligature}, +disc\index{discretionary hyphen}, glue\index{glue}, language\index{language}, +rule\index{rule}, and image\index{image} nodes. The parameter byte +contains the reference number. For example, the byte sequence |0x09| +|0x03| is equivalent to the node \.{<penalty *3>}. +In the long format these two-byte sequences are written, +``\.{\\P}$n$\.{\\}'' (penalty), +``\.{\\K}$n$\.{\\}'' (kern), +``\.{\\L}$n$\.{\\}'' (ligature), +``\.{\\D}$n$\.{\\}'' (disc), +``\.{\\G}$n$\.{\\}'' (glue), +``\.{\\S}$n$\.{\\}'' (speak or German ``Sprache''), +``\.{\\R}$n$\.{\\}'' (rule), and +``\.{\\I}$n$\.{\\}'' (image), where $n$ is the decimal representation + of the parameter value. + + +\item The control codes from $|txt_local|=|0x11|$ to |0x1C| are used +to reference one of the 12 font specific parameters\index{font +parameter}. In the long format they are written ``\.{\\a}'', +``\.{\\b}'', ``\.{\\c}'', \dots, ``\.{\\j}'', ``\.{\\k}'',``\.{\\l}''. + + +\item The control code $|txt_cc|=|0x1D|$ is used as a prefix for an +arbitrary character code represented as an UTF-8 multibyte sequence. +Its main purpose is providing a method for including character codes +less or equal to |0x20| which otherwise would be considered control +codes. In the long format, the byte sequence is written ``\.{\\C}$n$\.{\\}'' +where $n$ is the decimal representation of the character code. + + +\item The control code $|txt_node|=|0x1E|$ is used as a prefix for an +arbitrary node in short format. In the long format, it is written +``\.{<}'' and is followed by the node content in long format +terminated by ``\.{>}''. + +\item The control code $|txt_hyphen|=|0x1F|$ is used to access the +font specific discretionary hyphen\index{hyphen}. In the long format +it is simply written as ``\.{-}''. + +\item The control code $|txt_glue|=|0x20|$ is the space character, it +is used to access the font specific interword\index{interword glue} +glue. In the long format, we use the space character\index{space +character} ``\.{\ }'' as well. + +\item The control code $|txt_ignore|=|0xFB|$ is ignored, its position +can be used in a link to specify a position between two characters. In +the long format it is written as ``\.{\\@@}''. + +\enditemize +For the control codes, we define an enumeration type +and for references, a reference type. +@<hint types@>= +typedef enum { @+txt_font=0x00, txt_global=0x08, txt_local=0x11, + txt_cc=0x1D, txt_node=0x1E, txt_hyphen=0x1F, + txt_glue=0x20, txt_ignore=0xFB} txt_t; +@ + +\readcode +@s TXT symbol +@s TXT_START symbol +@s TXT_END symbol +@s TXT_FONT symbol +@s TXT_LOCAL symbol +@s TXT_GLOBAL symbol +@s TXT_FONT_GLUE symbol +@s TXT_FONT_HYPHEN symbol +@s TXT_CC symbol +@s TXT_IGNORE symbol +@s text symbol +@<scanning definitions@>= +%x TXT +@ + +@<symbols@>= +%token TXT_START TXT_END TXT_IGNORE +%token TXT_FONT_GLUE TXT_FONT_HYPHEN +%token <u> TXT_FONT TXT_LOCAL +%token <rf> TXT_GLOBAL +%token <u> TXT_CC +%type <u> text +@ + +@<scanning rules@>= +::@=\"@> :< SCAN_TXT_START; return TXT_START; >: + +<TXT>{ +::@=\"@> :< SCAN_TXT_END; return TXT_END; >: + +::@="<"@> :< SCAN_START; return START; >: +::@=">"@> :< QUIT("> not allowed in text mode");>: + +::@=\\\\@> :< yylval.u='\\'; return TXT_CC; >: +::@=\\\"@> :< yylval.u='"'; return TXT_CC; >: +::@=\\"<"@> :< yylval.u='<'; return TXT_CC; >: +::@=\\">"@> :< yylval.u='>'; return TXT_CC; >: +::@=\\" "@> :< yylval.u=' '; return TXT_CC; >: +::@=\\"-"@> :< yylval.u='-'; return TXT_CC; >: +::@=\\"@@"@> :< return TXT_IGNORE; >: + +::@=[ \t\r]*(\n[ \t\r]*)+@> :< return TXT_FONT_GLUE; >: +::@=\\[ \t\r]*\n[ \t\r]*@> :< ; >: + +::@=\\[0-7]@> :< yylval.u=yytext[1]-'0'; return TXT_FONT; >: + +::@=\\F[0-9]+\\@> :< SCAN_REF(font_kind); return TXT_GLOBAL; >: +::@=\\P[0-9]+\\@> :< SCAN_REF(penalty_kind); return TXT_GLOBAL; >: +::@=\\K[0-9]+\\@> :< SCAN_REF(kern_kind); return TXT_GLOBAL; >: +::@=\\L[0-9]+\\@> :< SCAN_REF(ligature_kind); return TXT_GLOBAL; >: +::@=\\D[0-9]+\\@> :< SCAN_REF(disc_kind); return TXT_GLOBAL; >: +::@=\\G[0-9]+\\@> :< SCAN_REF(glue_kind); return TXT_GLOBAL; >: +::@=\\S[0-9]+\\@> :< SCAN_REF(language_kind); return TXT_GLOBAL; >: +::@=\\R[0-9]+\\@> :< SCAN_REF(rule_kind); return TXT_GLOBAL; >: +::@=\\I[0-9]+\\@> :< SCAN_REF(image_kind); return TXT_GLOBAL; >: + + +::@=\\C[0-9]+\\@> :< SCAN_UDEC(yytext+2); return TXT_CC; >: + +::@=\\[a-l]@> :< yylval.u=yytext[1]-'a'; return TXT_LOCAL; >: +::@=" "@> :< return TXT_FONT_GLUE; >: +::@="-"@> :< return TXT_FONT_HYPHEN; >: + +::@={UTF8_1}@> :< SCAN_UTF8_1(yytext); return TXT_CC; >: +::@={UTF8_2}@> :< SCAN_UTF8_2(yytext); return TXT_CC; >: +::@={UTF8_3}@> :< SCAN_UTF8_3(yytext); return TXT_CC; >: +::@={UTF8_4}@> :< SCAN_UTF8_4(yytext); return TXT_CC; >: +} +@ + +@<scanning macros@>= +#define @[SCAN_REF(K)@] @[yylval.rf.k=K;@+ yylval.rf.n=atoi(yytext+2)@;@] +static int scan_level=0; +#define SCAN_START @[yy_push_state(INITIAL);@+if (1==scan_level++) hpos0=hpos;@] +#define SCAN_END @[if (scan_level--) yy_pop_state(); @/else QUIT("Too many '>' in line %d",yylineno)@] +#define SCAN_TXT_START @[BEGIN(TXT)@;@] +#define SCAN_TXT_END @[BEGIN(INITIAL)@;@] +@ +@s txt symbol + +@<parsing rules@>= +list: TXT_START position @| + {hpos+=4; /* start byte, two size byte, and boundary byte */ } + text TXT_END@| + { $$.k=text_kind;$$.p=$4; $$.s=(hpos-hstart)-$4; + hput_tags($2,hput_list($2+1, &($$)));@+}; +text: position @+| text txt; + +txt: TXT_CC { hput_txt_cc($1); } + | TXT_FONT { REF(font_kind,$1); hput_txt_font($1); } + | TXT_GLOBAL { REF($1.k,$1.n); hput_txt_global(&($1)); } + | TXT_LOCAL { RNG("Font parameter",$1,0,11); hput_txt_local($1); } + | TXT_FONT_GLUE { HPUTX(1); HPUT8(txt_glue); } + | TXT_FONT_HYPHEN { HPUTX(1);HPUT8(txt_hyphen); } + | TXT_IGNORE { HPUTX(1);HPUT8(txt_ignore); } + | { HPUTX(1); HPUT8(txt_node);} content_node; +@ + +The following function keeps track of the position in the current line. +It the line gets too long it will break the text at the next space +character. If no suitable space character comes along, +the line will be broken after any regular character. + +\writecode +@<write a text@>= +{@+if (l->s==0) hwritef(" \"\""); + else@/ + { int pos=nesting+20; /* estimate */ + hwritef(" \""); + while(hpos<hend)@/ + { int i=hget_txt(); + if (i<0) + { if (pos++<70) hwritec(' '); + else hwrite_nesting(), pos=nesting; + } + else if (i==1 && pos>=100)@/ + { hwritec('\\'); @+hwrite_nesting(); @+pos=nesting; @+} + else + pos+=i; + } + hwritec('"'); + } +} +@ + + +The function returns the number of characters written +because this information is needed in |hget_txt| below. + +@<write functions@>= +int hwrite_txt_cc(uint32_t c) +{@+ if (c<0x20) + return hwritef("\\C%d\\",c); + else@+ + switch(c) + { case '\\': return hwritef("\\\\"); + case '"': return hwritef("\\\""); + case '<': return hwritef("\\<"); + case '>': return hwritef("\\>"); + case ' ': return hwritef("\\ "); + case '-': return hwritef("\\-"); + default: return option_utf8?hwrite_utf8(c):hwritef("\\C%d\\",c); + } +} +@ + +\getcode +@<get macros@>= +#define @[HGET_GREF(K,S)@] {uint8_t n=HGET8;@+ REF(K,n); @+ return hwritef("\\" S "%d\\",n);@+} + +@ + +The function |hget_txt| reads a text element and writes it immediately. +To enable the insertion of line breaks when writing a text, we need to keep track +of the number of characters in the current line. For this purpose +the function |hget_txt| returns the number of characters written. +It returns $-1$ if a space character needs to be written +providing a good opportunity for a break. + +@<get functions@>= +int hget_txt(void) +{@+ if (*hpos>=0x80 && *hpos<=0xF7) + { if (option_utf8) + return hwrite_utf8(hget_utf8()); + else + return hwritef("\\C%d\\",hget_utf8()); + } + else @/ + { uint8_t a; + a=HGET8; + switch (a) + { case txt_font+0: return hwritef("\\0"); + case txt_font+1: return hwritef("\\1"); + case txt_font+2: return hwritef("\\2"); + case txt_font+3: return hwritef("\\3"); + case txt_font+4: return hwritef("\\4"); + case txt_font+5: return hwritef("\\5"); + case txt_font+6: return hwritef("\\6"); + case txt_font+7: return hwritef("\\7"); + case txt_global+0: HGET_GREF(font_kind,"F"); + case txt_global+1: HGET_GREF(penalty_kind,"P"); + case txt_global+2: HGET_GREF(kern_kind,"K"); + case txt_global+3: HGET_GREF(ligature_kind,"L"); + case txt_global+4: HGET_GREF(disc_kind,"D"); + case txt_global+5: HGET_GREF(glue_kind,"G"); + case txt_global+6: HGET_GREF(language_kind,"S"); + case txt_global+7: HGET_GREF(rule_kind,"R"); + case txt_global+8: HGET_GREF(image_kind,"I"); + case txt_local+0: return hwritef("\\a"); + case txt_local+1: return hwritef("\\b"); + case txt_local+2: return hwritef("\\c"); + case txt_local+3: return hwritef("\\d"); + case txt_local+4: return hwritef("\\e"); + case txt_local+5: return hwritef("\\f"); + case txt_local+6: return hwritef("\\g"); + case txt_local+7: return hwritef("\\h"); + case txt_local+8: return hwritef("\\i"); + case txt_local+9: return hwritef("\\j"); + case txt_local+10: return hwritef("\\k"); + case txt_local+11: return hwritef("\\l"); + case txt_cc: return hwrite_txt_cc(hget_utf8()); + case txt_node: { int i; + @<read the start byte |a|@>@; + i=hwritef("<"); + i+= hwritef("%s",content_name[KIND(a)]);@+ hget_content(a); + @<read and check the end byte |z|@>@; + hwritec('>');@+ return i+10; /* just an estimate */ + } + case txt_hyphen: hwritec('-'); @+return 1; + case txt_glue: return -1; + case '<': return hwritef("\\<"); + case '>': return hwritef("\\>"); + case '"': return hwritef("\\\""); + case '-': return hwritef("\\-"); + case txt_ignore: return hwritef("\\@@"); + default: hwritec(a); @+return 1; + } + } +} + +@ + + +\putcode +@<put functions@>= + +void hput_txt_cc(uint32_t c) +{ @+ if (c<=0x20) { HPUTX(2); HPUT8(txt_cc);@+ HPUT8(c); @+ } + else hput_utf8(c); +} + +void hput_txt_font(uint8_t f) +{@+ if (f<8) HPUTX(1),HPUT8(txt_font+f); + else QUIT("Use \\F%d\\ instead of \\%d for font %d in a text",f,f,f); +} + +void hput_txt_global(ref_t *d) +{ @+ HPUTX(2); + switch (d->k) + { case font_kind: HPUT8(txt_global+0);@+ break; + case penalty_kind: HPUT8(txt_global+1);@+ break; + case kern_kind: HPUT8(txt_global+2);@+ break; + case ligature_kind: HPUT8(txt_global+3);@+ break; + case disc_kind: HPUT8(txt_global+4);@+ break; + case glue_kind: HPUT8(txt_global+5);@+ break; + case language_kind: HPUT8(txt_global+6);@+ break; + case rule_kind: HPUT8(txt_global+7);@+ break; + case image_kind: HPUT8(txt_global+8);@+ break; + default: QUIT("Kind %s not allowed as a global reference in a text",NAME(d->k)); + } + HPUT8(d->n); +} + +void hput_txt_local(uint8_t n) +{ HPUTX(1); + HPUT8(txt_local+n); +} +@ + + +@<hint types@>= +typedef struct { @+kind_t k; @+int n; @+} ref_t; +@ + + +\section{Composite Nodes}\hascode +\label{composite} +The nodes that we consider in this section can contain one or more list nodes. +When we implement the parsing\index{parsing} routines +for composite nodes in the long format, we have to take into account +that parsing such a list node will already write the list node +to the output. So we split the parsing of composite nodes into several parts +and store the parts immediately after parsing them. On the parse stack, we will only +keep track of the info value. +This new strategy is not as transparent as our previous strategy used for +simple nodes where we had a clean separation of reading and writing: +reading would store the internal representation of a node and writing the internal +representation to output would start only after reading is completed. +The new strategy, however, makes it easier to reuse +the grammar\index{grammar} rules for the component nodes. + +Another rule applies to composite nodes: in the short format, the subnodes +will come at the end of the node, and especially a list node that contains content nodes +comes last. This helps when traversing the content section as we will see in +appendix~\secref{fastforward}. + +\subsection{Boxes}\label{boxnodes} +The central structuring elements of \TeX\ are boxes\index{box}. +Boxes have a height |h|, a depth |d|, and a width |w|. +The shift amount |a| shifts the contents of the box, the glue ratio\index{glue ratio} |r| is a factor +applied to the glue inside the box, the glue order |o| is its order of stretchability\index{stretchability}, +and the glue sign |s| is $-1$ for shrinking\index{shrinkability}, 0 for rigid, and $+1$ for stretching. +Most importantly, a box contains a list |l| of content nodes inside the box. + + +@<hint types@>= +typedef struct @/{@+ dimen_t h,d,w,a;@+ float32_t r;@+ int8_t s,o; @+list_t l; @+} box_t; +@ + +There are two types of boxes: horizontal\index{horizontal box} boxes +and vertical\index{vertical box} boxes. +The difference between the two is simple: +a horizontal box aligns the reference\index{reference point} +points of its content nodes horizontally, and a positive shift amount\index{shift amount} |a| +shifts the box down; +a vertical box aligns\index{alignment} the reference\index{reference point} +points vertically, and a positive shift amount |a| shifts the box right. + +Not all box parameters are used frequently. In the short format, we use the info bits +to indicated which of the parameters are used. +Where as the width of a horizontal box is most of the time (80\%) nonzero, +other parameters are most of the time zero, +like the shift amount (99\%) or the glue settings (99.8\%). +The depth is zero in about 77\%, the height in about 53\%, +and both together are zero in about 47\%. The results for vertical boxes, +which constitute about 20\% of all boxes, are similar, +except that the depth is zero in about 89\%, +but the height and width are almost never zero. +For this reason we use bit |b001| to indicate a nonzero depth, +bit |b010| for a nonzero shift amount, and |b100| for nonzero glue settings. +Glue sign and glue order can be packed as two nibbles in a single byte. +% A different use of the info bits for vertical and horizontal boxes is possible, +% but does not warrant the added complexity. + + + +\goodbreak +\readcode +@s HBOX symbol +@s VBOX symbol +@s box symbol +@s boxparams symbol +@s hbox_node symbol +@s vbox_node symbol +@s box_dimen symbol +@s box_shift symbol +@s box_glue_set symbol +@<symbols@>= +%token HBOX "hbox" +%token VBOX "vbox" +%token SHIFTED "shifted" +%type <info> box box_dimen box_shift box_glue_set + +@ +@<scanning rules@>= +::@=hbox@> :< return HBOX; >: +::@=vbox@> :< return VBOX; >: +::@=shifted@> :< return SHIFTED; >: +@ + +@<parsing rules@>=@/ + +box_dimen: dimension dimension dimension @/ + {$$= hput_box_dimen($1,$2,$3); }; +box_shift: {$$=b000;} @+ + | SHIFTED dimension {$$=hput_box_shift($2);}; + +box_glue_set: {$$=b000;} + | PLUS stretch { $$=hput_box_glue_set(+1,$2.f,$2.o); } + | MINUS stretch { $$=hput_box_glue_set(-1,$2.f,$2.o); }; + + +box: box_dimen box_shift box_glue_set list {$$=$1|$2|$3; }; + +hbox_node: start HBOX box END { hput_tags($1, TAG(hbox_kind,$3)); }; +vbox_node: start VBOX box END { hput_tags($1, TAG(vbox_kind,$3)); }; +content_node: hbox_node @+ | vbox_node; +@ + +\writecode +@<write functions@>= +void hwrite_box(box_t *b) +{ hwrite_dimension(b->h); + hwrite_dimension(b->d); + hwrite_dimension(b->w); + if (b->a!=0) { hwritef(" shifted"); @+hwrite_dimension(b->a); @+} + if (b->r!=0.0 && b->s!=0 )@/ + { @+if (b->s>0) @+hwritef(" plus"); @+else @+hwritef(" minus"); + @+hwrite_float64(b->r); @+hwrite_order(b->o); + } + hwrite_list(&(b->l)); +} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(hbox_kind,b000): {box_t b; @+HGET_BOX(b000,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b001): {box_t b; @+HGET_BOX(b001,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b010): {box_t b; @+HGET_BOX(b010,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b011): {box_t b; @+HGET_BOX(b011,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b100): {box_t b; @+HGET_BOX(b100,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b101): {box_t b; @+HGET_BOX(b101,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b110): {box_t b; @+HGET_BOX(b110,b); @+hwrite_box(&b);@+} @+ break; +case TAG(hbox_kind,b111): {box_t b; @+HGET_BOX(b111,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b000): {box_t b; @+HGET_BOX(b000,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b001): {box_t b; @+HGET_BOX(b001,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b010): {box_t b; @+HGET_BOX(b010,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b011): {box_t b; @+HGET_BOX(b011,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b100): {box_t b; @+HGET_BOX(b100,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b101): {box_t b; @+HGET_BOX(b101,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b110): {box_t b; @+HGET_BOX(b110,b); @+hwrite_box(&b);@+} @+ break; +case TAG(vbox_kind,b111): {box_t b; @+HGET_BOX(b111,b); @+hwrite_box(&b);@+} @+ break; +@ + +@<get macros@>= +#define @[HGET_BOX(I,B)@] \ +HGET32(B.h);\ +if ((I)&b001) HGET32(B.d); @+ else B.d=0;\ +HGET32(B.w);\ +if ((I)&b010) HGET32(B.a); @+else B.a=0;\ +if ((I)&b100) @/{ B.r=hget_float32();@+ B.s=HGET8; @+ B.o=B.s&0xF; @+B.s=B.s>>4;@+ }\ +else { B.r=0.0;@+ B.o=B.s=0;@+ }\ +hget_list(&(B.l)); +@ + +@<get functions@>= +void hget_hbox_node(void) +{ box_t b; + @<read the start byte |a|@>@; + if (KIND(a)!=hbox_kind) QUIT("Hbox expected at 0x%x got %s",node_pos,NAME(a)); + HGET_BOX(INFO(a),b);@/ + @<read and check the end byte |z|@>@; + hwrite_start();@+ + hwritef("hbox");@+ + hwrite_box(&b);@+ + hwrite_end(); +} + + +void hget_vbox_node(void) +{ box_t b; + @<read the start byte |a|@>@; + if (KIND(a)!=vbox_kind) QUIT("Vbox expected at 0x%x got %s",node_pos,NAME(a)); + HGET_BOX(INFO(a),b);@/ + @<read and check the end byte |z|@>@; + hwrite_start();@+ + hwritef("vbox");@+ + hwrite_box(&b);@+ + hwrite_end(); +} +@ + +\putcode +@<put functions@>= + +info_t hput_box_dimen(dimen_t h, dimen_t d, dimen_t w) +{ info_t i; + @+HPUT32(h); + if (d!=0) { HPUT32(d); @+i=b001;@+ } @+else@+ i=b000; + HPUT32(w); + return i; +} +info_t hput_box_shift(dimen_t a) +{ @+if (a!=0) { @+ HPUT32(a); @+return @+ b010;@+} @+ else @+return b000; +} + +info_t hput_box_glue_set(int8_t s, float32_t r, order_t o) +{ @+if (r!=0.0 && s!=0 ) + { hput_float32(r);@+ + HPUT8((s<<4)|o);@+ + return b100;@+ + } + else return b000; +} + +@ + +\subsection{Extended Boxes} +Hi\TeX\ produces two kinds of extended\index{extended box} horizontal +boxes, |hpack_kind| and |hset_kind|, and the same for vertical boxes +using |vpack_kind| and |vset_kind|. Let us focus on horizontal boxes; +the handling of vertical boxes is completely parallel. + +The \\{hpack} procedure of Hi\TeX\ produces an extended box of |hset_kind| +either if it is given an extended\index{extended dimension} dimension as its width +or if it discovers that the width of its content is an extended +dimension. After the final width of the box has been computed in the +viewer, it just remains to set the glue; a very simple operation +indeed. + +If the \\{hpack} procedure of Hi\TeX\ can not determine the natural +dimensions of the box content because it contains +paragraphs\index{paragraph} or other extended boxes, it produces a box +of |hpack_kind|. Now the viewer needs to traverse the list of content +nodes to determine the natural\index{natural dimension} +dimensions. Even the amount of stretchability\index{stretchability} +and shrinkability\index{shrinkability} has to be determined in the +viewer. For example, the final stretchability of a paragraph with some +stretchability in the baseline\index{baseline skip} skip will depend +on the number of lines which, in turn, depends on \.{hsize}. It is +not possible to merge these traversals of the box content with the +traversal necessary when displaying the box. The latter needs to +convert glue nodes into positioning instructions which requires a +fixed glue\index{glue ratio} ratio. The computation of the glue ratio, +however, requires a complete traversal of the content. + +In the short format of a box node of type |hset_kind|, |vset_kind|, +|hpack_kind|, or |vpack_kind|, the info bit |b100| indicates, if set, +a complete extended dimension, and if unset, a reference to a +predefined extended dimension for the target size; the info bit |b010| +indicates a nonzero shift amount. For a box of type |hset_kind| or +|vset_kind|, the info bit |b001| indicates, if set, a nonzero depth. +For a box of type |hpack_kind| or |vpack_kind|, the info bit |b001| +indicates, if set, an additional target size, and if unset, an exact +target size. For a box of type |vpack_kind| also the maximum depth is +given. + +\readcode +@s xbox symbol +@s hpack symbol +@s vpack symbol +@s box_goal symbol +@s HPACK symbol +@s HSET symbol +@s VPACK symbol +@s VSET symbol +@s TO symbol +@s ADD symbol +@s box_flex symbol +@s vxbox_node symbol +@s hxbox_node symbol +@s DEPTH symbol + +@<symbols@>= +%token HPACK "hpack" +%token HSET "hset" +%token VPACK "vpack" +%token VSET "vset" +%token DEPTH "depth" +%token ADD "add" +%token TO "to" +%type <info> xbox box_goal hpack vpack +@ + +@<scanning rules@>= +::@=hpack@> :< return HPACK; >: +::@=hset@> :< return HSET; >: +::@=vpack@> :< return VPACK; >: +::@=vset@> :< return VSET; >: +::@=add@> :< return ADD; >: +::@=to@> :< return TO; >: +::@=depth@> :< return DEPTH; >: +@ + +@<parsing rules@>= +box_flex: plus minus { hput_stretch(&($1));hput_stretch(&($2)); }; +xbox: box_dimen box_shift box_flex xdimen_ref list {$$=$1|$2;} + | box_dimen box_shift box_flex xdimen_node list {$$=$1|$2|b100;}; + +box_goal: TO xdimen_ref {$$=b000;} + | ADD xdimen_ref {$$=b001;} + | TO xdimen_node {$$=b100;} + | ADD xdimen_node {$$=b101;}; + +hpack: box_shift box_goal list {$$=$2;}; +vpack: box_shift MAX DEPTH dimension {HPUT32($4);} @/ box_goal list {$$= $1|$6;}; + +vxbox_node: start VSET xbox END { hput_tags($1, TAG(vset_kind,$3)); } + | start VPACK vpack END { hput_tags($1, TAG(vpack_kind,$3)); }; + + +hxbox_node: start HSET xbox END { hput_tags($1, TAG(hset_kind,$3)); } + | start HPACK hpack END { hput_tags($1, TAG(hpack_kind,$3)); }; + +content_node: vxbox_node | hxbox_node; + @ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(hset_kind,b000): HGET_SET(b000); @+ break; +case TAG(hset_kind,b001): HGET_SET(b001); @+ break; +case TAG(hset_kind,b010): HGET_SET(b010); @+ break; +case TAG(hset_kind,b011): HGET_SET(b011); @+ break; +case TAG(hset_kind,b100): HGET_SET(b100); @+ break; +case TAG(hset_kind,b101): HGET_SET(b101); @+ break; +case TAG(hset_kind,b110): HGET_SET(b110); @+ break; +case TAG(hset_kind,b111): HGET_SET(b111); @+ break;@# + +case TAG(vset_kind,b000): HGET_SET(b000); @+ break; +case TAG(vset_kind,b001): HGET_SET(b001); @+ break; +case TAG(vset_kind,b010): HGET_SET(b010); @+ break; +case TAG(vset_kind,b011): HGET_SET(b011); @+ break; +case TAG(vset_kind,b100): HGET_SET(b100); @+ break; +case TAG(vset_kind,b101): HGET_SET(b101); @+ break; +case TAG(vset_kind,b110): HGET_SET(b110); @+ break; +case TAG(vset_kind,b111): HGET_SET(b111); @+ break;@# + +case TAG(hpack_kind,b000): HGET_PACK(hpack_kind,b000); @+ break; +case TAG(hpack_kind,b001): HGET_PACK(hpack_kind,b001); @+ break; +case TAG(hpack_kind,b010): HGET_PACK(hpack_kind,b010); @+ break; +case TAG(hpack_kind,b011): HGET_PACK(hpack_kind,b011); @+ break; +case TAG(hpack_kind,b100): HGET_PACK(hpack_kind,b100); @+ break; +case TAG(hpack_kind,b101): HGET_PACK(hpack_kind,b101); @+ break; +case TAG(hpack_kind,b110): HGET_PACK(hpack_kind,b110); @+ break; +case TAG(hpack_kind,b111): HGET_PACK(hpack_kind,b111); @+ break;@# + +case TAG(vpack_kind,b000): HGET_PACK(vpack_kind,b000); @+ break; +case TAG(vpack_kind,b001): HGET_PACK(vpack_kind,b001); @+ break; +case TAG(vpack_kind,b010): HGET_PACK(vpack_kind,b010); @+ break; +case TAG(vpack_kind,b011): HGET_PACK(vpack_kind,b011); @+ break; +case TAG(vpack_kind,b100): HGET_PACK(vpack_kind,b100); @+ break; +case TAG(vpack_kind,b101): HGET_PACK(vpack_kind,b101); @+ break; +case TAG(vpack_kind,b110): HGET_PACK(vpack_kind,b110); @+ break; +case TAG(vpack_kind,b111): HGET_PACK(vpack_kind,b111); @+ break; +@ + + +@<get macros@>= +#define @[HGET_SET(I)@] @/\ + { dimen_t h; @+HGET32(h); @+hwrite_dimension(h);@+}\ + { dimen_t d; @+if ((I)&b001) HGET32(d); @+ else d=0;@+hwrite_dimension(d); @+}\ + { dimen_t w; @+HGET32(w); @+hwrite_dimension(w);@+} \ +if ((I)&b010) { dimen_t a; @+HGET32(a); hwritef(" shifted"); @+hwrite_dimension(a);@+}\ + { stretch_t p; @+HGET_STRETCH(p);@+hwrite_plus(&p);@+}\ + { stretch_t m; @+HGET_STRETCH(m);@+hwrite_minus(&m);@+}\ + if ((I)&b100) {xdimen_t x;@+ hget_xdimen_node(&x); @+hwrite_xdimen_node(&x);@+} else HGET_REF(xdimen_kind)@;\ + { list_t l; @+hget_list(&l);@+ hwrite_list(&l); @+} +@# + +#define @[HGET_PACK(K,I)@] @/\ + if ((I)&b010) { dimen_t d; @+HGET32(d); hwritef(" shifted"); @+hwrite_dimension(d); @+ }\ + if (K==vpack_kind) { dimen_t d; @+HGET32(d); hwritef(" max depth");@+hwrite_dimension(d); @+ }\ + if ((I)&b001) hwritef(" add");@+ else hwritef(" to");\ + if ((I)&b100) {xdimen_t x;@+ hget_xdimen_node(&x);@+hwrite_xdimen_node(&x);@+}\ + else @+HGET_REF(xdimen_kind);\ + { list_t l; @+hget_list(&l);@+ hwrite_list(&l); @+} +@ + + +\subsection{Leaders}\label{leaders} +Leaders\index{leaders} are a special type of glue that is best explained by a few +examples. +Where as ordinary glue fills its designated space with \hfil\ whiteness,\break +leaders fill their designated space with either a rule \xleaders\hrule\hfil\ or\break +some sort of repeated\leaders\hbox to 15pt{$\hss.\hss$}\hfil content.\break +In multiple leaders, the dots\leaders\hbox to 15pt{$\hss.\hss$}\hfil are usually aligned\index{alignment} across lines,\break +as in the last\leaders\hbox to 15pt{$\hss.\hss$}\hfil three lines.\break +Unless you specify centered\index{centered}\cleaders\hbox to 15pt{$\hss.\hss$}\hfil leaders\break +or you specify expanded\index{expanded}\xleaders\hbox to 15pt{$\hss.\hss$}\hfil leaders.\break +The former pack the repeated content tight and center +the repeated content in the available space, the latter distributes +the extra space between all the repeated instances. + +In the short format, the two lowest info bits store the type +of leaders: 1 for aligned, 2 for centered, and 3 for expanded. +The |b100| info bit is usually set and only zero in the unlikely +case that the glue is zero and therefore not present. + +\readcode +@s LEADERS symbol +@s ALIGN symbol +@s CENTER symbol +@s EXPAND symbol +@s leaders symbol +@s ltype symbol +@<symbols@>= +%token LEADERS "leaders" +%token ALIGN "align" +%token CENTER "center" +%token EXPAND "expand" +%type <info> leaders +%type <info> ltype +@ + +@<scanning rules@>= +::@=leaders@> :< return LEADERS; >: +::@=align@> :< return ALIGN; >: +::@=center@> :< return CENTER; >: +::@=expand@> :< return EXPAND; >: +@ +@<parsing rules@>= +ltype: {$$=1;} | ALIGN {$$=1;} @+| CENTER {$$=2;} @+| EXPAND {$$=3;}; +leaders: glue_node ltype rule_node {@+if ($1) $$=$2|b100;@+else $$=$2; @+} + | glue_node ltype hbox_node {@+if ($1) $$=$2|b100;@+else $$=$2;@+} + | glue_node ltype vbox_node {@+if ($1) $$=$2|b100;@+else $$=$2;@+}; +content_node: start LEADERS leaders END @| {@+ hput_tags($1, TAG(leaders_kind, $3));} +@ + +\writecode +@<write functions@>= +void hwrite_leaders_type(int t) +{@+ + if (t==2) hwritef(" center"); + else if (t==3) hwritef(" expand"); +} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(leaders_kind,1): @+ HGET_LEADERS(1); @+break; +case TAG(leaders_kind,2): @+ HGET_LEADERS(2); @+break; +case TAG(leaders_kind,3): @+ HGET_LEADERS(3); @+break; +case TAG(leaders_kind,b100|1): @+ HGET_LEADERS(b100|1); @+break; +case TAG(leaders_kind,b100|2): @+ HGET_LEADERS(b100|2); @+break; +case TAG(leaders_kind,b100|3): @+ HGET_LEADERS(b100|3); @+break; +@ +@<get macros@>= +#define @[HGET_LEADERS(I)@]@/ \ +if ((I)&b100) hget_glue_node();\ +hwrite_leaders_type((I)&b011);\ +if (KIND(*hpos)==rule_kind) hget_rule_node(); \ +else if (KIND(*hpos)==hbox_kind) hget_hbox_node(); \ +else hget_vbox_node(); +@ + +\subsection{Baseline Skips} +Baseline\index{baseline skip} skips are small amounts of glue inserted +between two consecutive lines of text. To get nice looking pages, the +amount of glue\index{glue} inserted must take into account the depth +of the line above the glue and the height of the line below the glue +to achieve a constant distance of the baselines. For example, if we +have the lines +\medskip + +\qquad\vbox{\hsize=0.5\hsize\noindent +``There is no\hfil\break +more gas\hfil\break +in the tank.'' +}\hss + +\medskip\noindent +\TeX\ will insert 7.69446pt of baseline skip between the first and the +second line and 3.11111pt of baseline skip between the second and the +third line. This is due to the fact that the first line has no +descenders, its depth is zero, the second line has no ascenders but +the ``g'' descends below the baseline, and the third line has +ascenders (``t'', ``h'',\dots) so it is higher than the second line. +\TeX's choice of baseline skips ensures that the baselines are exactly +12pt apart in both cases. + +Things get more complicated if the text contains mathematical formulas because then +a line can get so high or deep that it is impossible to keep the distance between +baselines constant without two adjacent lines touching each other. In such cases, +\TeX\ will insert a small minimum line skip glue\index{line skip glue}. + +For the whole computation, \TeX\ uses three parameters: {\tt base\-line\-skip}, +{\tt line\-skip\-limit},\index{line skip limit} and +{\tt lineskip}. {\tt baselineskip} is a glue value; its size is the +normal distance of two baselines. \TeX\ adjusts the size of the +{\tt baselineskip} glue for the height and the depth of the two lines and +then checks the result against {\tt lineskiplimit}. If the result is +smaller than {\tt lineskiplimit} it will use the {\tt lineskip} glue +instead. + +Because the depth and the height of lines depend on the outcome +of the line breaking\index{line breaking} +routine, baseline computations must be done in the viewer. +The situation gets even more complicated because \TeX\ can manipulate the insertion +of baseline skips in various ways. Therefore \HINT\ requires the insertion of +baseline nodes wherever the viewer is supposed to perform a baseline skip +computation. + +In the short format of a baseline definition, we store only +the nonzero components and use the +info bits to mark them: |b100| implies $|bs|\ne0$, +|b010| implies $|ls|\ne 0$, and |b001| implies $|lslimit|\ne 0$. +If the baseline has only zero components, we put a reference to baseline number 0 +in the output. + +@<hint basic types@>= +typedef struct {@+ +glue_t bs, ls;@+ +dimen_t lsl;@+ +} baseline_t; +@ + + + +\readcode +@s BASELINE symbol +@s baseline symbol +@<symbols@>= +%token BASELINE "baseline" +%type <info> baseline +@ +@<scanning rules@>= +::@=baseline@> :< return BASELINE; >: +@ + +@<parsing rules@>= +baseline: dimension { if ($1!=0) HPUT32($1); } + glue_node glue_node @/{ $$=b000; if ($1!=0) $$|=b001; + if ($3) $$|=b100; + if ($4) $$|=b010; + @+}; +content_node: start BASELINE baseline END @/ +{ @+if ($3==b000) HPUT8(0); @+hput_tags($1,TAG(baseline_kind, $3)); }; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(baseline_kind,b001): { baseline_t b;@+ HGET_BASELINE(b001,b);@+ }@+break; +case TAG(baseline_kind,b010): { baseline_t b;@+ HGET_BASELINE(b010,b);@+ }@+break; +case TAG(baseline_kind,b011): { baseline_t b;@+ HGET_BASELINE(b011,b);@+ }@+break; +case TAG(baseline_kind,b100): { baseline_t b;@+ HGET_BASELINE(b100,b);@+ }@+break; +case TAG(baseline_kind,b101): { baseline_t b;@+ HGET_BASELINE(b101,b);@+ }@+break; +case TAG(baseline_kind,b110): { baseline_t b;@+ HGET_BASELINE(b110,b);@+ }@+break; +case TAG(baseline_kind,b111): { baseline_t b;@+ HGET_BASELINE(b111,b);@+ }@+break; +@ + +@<get macros@>= +#define @[HGET_BASELINE(I,B)@] \ + if((I)&b001) HGET32((B).lsl); @+else B.lsl=0; hwrite_dimension(B.lsl);\ + if((I)&b100) hget_glue_node(); \ + else {B.bs.p.o=B.bs.m.o=B.bs.w.w=0; @+B.bs.w.h=B.bs.w.v=B.bs.p.f=B.bs.m.f=0.0; @+hwrite_glue_node(&(B.bs));@+}\ + if((I)&b010) hget_glue_node(); \ + else {B.ls.p.o=B.ls.m.o=B.ls.w.w=0; @+B.ls.w.h=B.ls.w.v=B.ls.p.f=B.ls.m.f=0.0; @+hwrite_glue_node(&(B.ls));@+} +@ + + +\putcode +@<put functions@>= +uint8_t hput_baseline(baseline_t *b) +{ info_t info=b000; + if (!ZERO_GLUE(b->bs)) @+info|=b100; + if (!ZERO_GLUE(b->ls)) @+ info|=b010; + if (b->lsl!=0) { @+ HPUT32(b->lsl); @+info|=b001; @+} + return TAG(baseline_kind,info); +} +@ + + + +\subsection{Ligatures} +Ligatures\index{ligature} occur only in horizontal lists. They specify characters +that combine the glyphs of several characters into one specialized +glyph. For example in the word ``{\it difficult\/}'' the three letters +``{\it f{}f{}i\/}'' are combined into the ligature ``{\it ffi\/}''. +Hence, a ligature is very similar to a simple glyph node; the +characters that got replaced are, however, retained in the ligature +because they might be needed for example to support searching. Since +ligatures are therefore only specialized list of characters and since +we have a very efficient way to store such lists of characters, namely +as a |text|, input and output of ligatures is quite simple. + +The info value zero is reserved for references to a ligature. If the +info value is between 1 and 6, it gives the number of bytes used to encode +the characters in UTF8. Note that a ligature will always include a +glyph byte, so the minimum size is 1. A typical ligature like ``{\it fi\/}'' +will need 3 byte: the ligature character ``{\it fi\/}'', and +the replacement characters ``f'' and ''i''. More byte might be +required if the character codes exceed |0x7F| since we use the UTF8 +encoding scheme for larger character codes. If the info value is 7, +a full text node follows the font byte. In the long +format, we give the font, the character code, and then the replacement +characters represented as a text. + +@<hint types@>= +typedef struct{@+uint8_t f; @+list_t l;@+} lig_t; +@ + +\readcode +@s ref symbol +@s LIGATURE symbol +@s ligature symbol +@s cc_list symbol +@s lig_cc symbol +@<symbols@>= +%token LIGATURE "ligature" +%type <u> lig_cc +%type <lg> ligature +%type <u> ref +@ +@<scanning rules@>= +::@=ligature@> :< return LIGATURE; >: +@ + +@<parsing rules@>=@/ +cc_list:@+ | cc_list TXT_CC { hput_utf8($2); }; +lig_cc: UNSIGNED {RNG("UTF-8 code",$1,0,0x1FFFFF);$$=hpos-hstart; hput_utf8($1); }; +lig_cc: CHARCODE {$$=hpos-hstart; hput_utf8($1); }; +ref: REFERENCE { HPUT8($1); $$=$1; }; +ligature: ref { REF(font_kind,$1);} lig_cc TXT_START cc_list TXT_END @/ + { $$.f=$1; $$.l.p=$3; $$.l.s=(hpos-hstart)-$3; + RNG("Ligature size",$$.l.s,0,255);}; +content_node: start LIGATURE ligature END {hput_tags($1,hput_ligature(&($3)));}; +@ + +\writecode +@<write functions@>= +void hwrite_ligature(lig_t *l) +{ uint32_t pos=hpos-hstart; + hwrite_ref(l->f); + hpos=l->l.p+hstart; + hwrite_charcode(hget_utf8()); + hwritef(" \""); + while (hpos<hstart+l->l.p+l->l.s) + hwrite_txt_cc(hget_utf8()); + hwritec('"'); + hpos=hstart+pos; +} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(ligature_kind,1):@+ {lig_t l; @+HGET_LIG(1,l);@+} @+break; +case TAG(ligature_kind,2):@+ {lig_t l; @+HGET_LIG(2,l);@+} @+break; +case TAG(ligature_kind,3):@+ {lig_t l; @+HGET_LIG(3,l);@+} @+break; +case TAG(ligature_kind,4):@+ {lig_t l; @+HGET_LIG(4,l);@+} @+break; +case TAG(ligature_kind,5):@+ {lig_t l; @+HGET_LIG(5,l);@+} @+break; +case TAG(ligature_kind,6):@+ {lig_t l; @+HGET_LIG(6,l);@+} @+break; +case TAG(ligature_kind,7):@+ {lig_t l; @+HGET_LIG(7,l);@+} @+break; +@ +@<get macros@>= +#define @[HGET_LIG(I,L)@] @/\ +(L).f=HGET8;REF(font_kind,(L).f);\ +if ((I)==7) hget_list(&((L).l)); \ +else { (L).l.s=(I); (L).l.p=hpos-hstart; @+ hpos+=(L).l.s;} \ +hwrite_ligature(&(L)); +@ + +\putcode +@<put functions@>= +uint8_t hput_ligature(lig_t *l) +{ @+if (l->l.s < 7) return TAG(ligature_kind,l->l.s); + else@/ + { uint32_t pos=l->l.p; + hput_tags(pos,hput_list(pos+1, &(l->l))); + return TAG(ligature_kind,7); + } +} +@ + + +\subsection{Discretionary breaks}\label{discbreak}\index{discretionary break} +\HINT\ is capable to break lines into paragraphs. It does this +primarily at interword spaces but it might also break a line in the +middle of a word if it finds a discretionary\index{discretionary break} +line break there. These discretionary breaks are usually +provided by an automatic hyphenation algorithm but they might be also +explicitly\index{explicit} inserted by the author of a +document. + +When a line break occurs at such a discretionary break, the line +before the break ends with a |pre_break| list of nodes, the line after +the break starts with a |post_break| list of nodes, and the next +|replace_count| nodes after the discretionary break will be +ignored. Both lists must consist entirely of glyphs\index{glyph}, +kerns\index{kern}, boxes\index{box}, rules\index{rule}, or +ligatures\index{ligature}. For example, an ordinary discretionary +break will have a |pre_break| list containing ``-'', an empty +|post_break| list, and a |replace_count| of zero. + +The long format starts with an optional ``{\tt !}'', indicating an +explicit discretionary break, followed by the replace-count. +Then comes the pre-break list followed by the post-break list. +The replace-count can be omitted if it is zero; +an empty post-break list may be omitted as well. +Both list may be omitted only if both are empty. + +In the short format, the three components of a disc node are stored +in this order: |replace_count|, |pre_break| list, and |post_break| list. +The |b100| bit in the info value indicates the presence of a replace-count, +the |b010| bit the presence of a |pre_break| list, +and the |b001| bit the presence of a |post_break| list. +Since the info value |b000| is reserved for references, at least one +of these must be specified; so we represent a node with empty lists +and a replace\index{replace count} count of zero using the info value +|b100| and a zero byte for the replace count. + +Replace counts must be in the range 0 to 31; so the short format can +set the high bit of the replace count to indicate an explicit\index{explicit} break. + +@<hint types@>= +typedef struct disc_t@+ {@+ bool x; @+list_t p,q;@+ uint8_t r;@+ } disc_t; +@ + + +\readcode +@s DISC symbol +@s disc symbol +@s disc_node symbol +@s replace_count symbol + +@<symbols@>= +%token DISC "disc" +%type <dc> disc +%type <u> replace_count +@ +@<scanning rules@>= +::@=disc@> :< return DISC; >: +@ + +@<parsing rules@>=@/ +replace_count: explicit {@+ if ($1) {$$=0x80; HPUT8(0x80);@+}@+ else $$=0x00;@+} + | explicit UNSIGNED { RNG("Replace count",$2,0,31); + $$=($2)|(($1)?0x80:0x00); @+ if ($$!=0) HPUT8($$);@+}; +disc: replace_count list list { $$.r=$1;$$.p=$2; $$.q=$3; + if ($3.s==0) { hpos=hpos-2;@+ if ($2.s==0) hpos=hpos-2; @+}@+} + | replace_count list { $$.r=$1;$$.p=$2; if ($2.s==0) hpos=hpos-2;@+ $$.q.s=0; } + | replace_count { $$.r=$1;$$.p.s=0; $$.q.s=0; }; + + +disc_node: start DISC disc END + {hput_tags($1,hput_disc(&($3)));}; + +content_node: disc_node; +@ + +\writecode +@<write functions@>= +void hwrite_disc(disc_t *h) +{ @+hwrite_explicit(h->x); + if (h->r!=0) hwritef(" %d",h->r); + if (h->p.s!=0 || h->q.s!=0) hwrite_list(&(h->p)); + if (h->q.s!=0) hwrite_list(&(h->q)); +} +void hwrite_disc_node(disc_t *h) +{ @+ hwrite_start(); @+hwritef("disc"); @+ hwrite_disc(h); @+hwrite_end();} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(disc_kind,b001): {disc_t h; @+HGET_DISC(b001,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b010): {disc_t h; @+HGET_DISC(b010,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b011): {disc_t h; @+HGET_DISC(b011,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b100): {disc_t h; @+HGET_DISC(b100,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b101): {disc_t h; @+HGET_DISC(b101,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b110): {disc_t h; @+HGET_DISC(b110,h);@+ hwrite_disc(&h); @+} @+break; +case TAG(disc_kind,b111): {disc_t h; @+HGET_DISC(b111,h);@+ hwrite_disc(&h); @+} @+break; +@ + +@<get macros@>= +#define @[HGET_DISC(I,Y)@]\ +if ((I)&b100) {uint8_t r=HGET8; (Y).r=r&0x7F; @+ RNG("Replace count",(Y).r,0,31); @+(Y).x=(r&0x80)!=0; @+}\ +@+else { (Y).r=0; @+ (Y).x=false;@+}\ +if ((I)&b010) hget_list(&((Y).p)); else { (Y).p.p=hpos-hstart; @+(Y).p.s=0; @+(Y).p.k=list_kind; @+}\ +if ((I)&b001) hget_list(&((Y).q)); else { (Y).q.p=hpos-hstart; @+(Y).q.s=0; @+(Y).q.k=list_kind; @+} +@ + +@<get functions@>= +void hget_disc_node(disc_t *h) +{ @<read the start byte |a|@>@; + if (KIND(a)!=disc_kind || INFO(a)==b000) + QUIT("Hyphen expected at 0x%x got %s,%d",node_pos,NAME(a),INFO(a)); + HGET_DISC(INFO(a),*h); + @<read and check the end byte |z|@>@; +} +@ + +When |hput_disc| is called, the node is already written to the output, +but empty lists might have been deleted, and the info value needs to be determined. +Because the info value |b000| is reserved for references, a zero reference +count is written to avoid this case. +\putcode +@<put functions@>= +uint8_t hput_disc(disc_t *h) +{ info_t info=b000; + if (h->r!=0) info|=b100; + if (h->q.s!=0) info|=b011; + else if (h->p.s!=0) info|=b010; + if (info==b000) { @+info|=b100; @+HPUT8(0);@+} + return TAG(disc_kind,info); +} +@ +\subsection{Paragraphs} +The most important procedure that the \HINT\ viewer inherits from \TeX\ is the +line breaking routine. If the horizontal size of the paragraph is not known, +breaking the paragraph\index{paragraph} into lines must be postponed and this is done by creating +a paragraph node. The paragraph node must contain all information that \TeX's +line breaking\index{line breaking} algorithm needs to do its job. + +Besides the horizontal list describing the content of the paragraph and +the extended dimension describing the horizontal size, +this is the set of parameters that guide the line breaking algorithm: + +\itemize +\item +Integer parameters:\hfill\break +{\tt pretolerance} (badness tolerance before hyphenation),\hfill\break +{\tt tolerance} (badness tolerance after hyphenation),\hfill\break +{\tt line\_penalty} (added to the badness of every line, increase to get fewer lines),\hfill\break +{\tt hy\-phen\_pe\-nal\-ty} (penalty for break after hyphenation break),\hfill\break +{\tt ex\_hy\-phen\_pe\-nal\-ty} (penalty for break after explicit\index{explicit} break),\hfill\break +{\tt doub\-le\_hy\-phen\_de\-merits} (demerits for double hyphen break),\hfill\break +{\tt final\_hyphen\_de\-me\-rits} (demerits for final hyphen break),\hfill\break +{\tt adj\_demerits} (demerits for adjacent incompatible lines),\hfill\break +{\tt looseness} (make the paragraph that many lines longer than its optimal size),\hfill\break +{\tt inter\_line\_penalty} (additional penalty between lines),\hfill\break +{\tt club\_pe\-nal\-ty} (penalty for creating a club line),\hfill\break +{\tt widow\_penalty} (penalty for creating a widow line),\hfill\break +{\tt display\_widow\_penalty} (ditto, just before a display),\hfill\break +{\tt bro\-ken\_pe\-nal\-ty} (penalty for breaking a page at a broken line),\hfill\break +{\tt hang\_af\-ter} (start/end hanging indentation at this line). +\item +Dimension parameters:\hfill\break +{\tt line\_skip\_limit} (threshold for {\tt line\_skip} instead of {\tt base\-line\_skip}),\hfill\break +{\tt hang\_in\-dent} (amount of hanging indentation),\hfill\break +{\tt emergency\_stretch} (stretchability added to every line in the final pass of line breaking). +\item +Glue parameters:\hfill\break +{\tt baseline\_skip} (desired glue between baselines),\hfill\break +{\tt line\_skip} (interline glue if {\tt baseline\_skip} is infeasible),\hfill\break +{\tt left\_skip} (glue at left of justified lines),\hfill\break +{\tt right\_skip} (glue at right of justified lines),\hfill\break +{\tt par\_fill\_skip} (glue on last line of paragraph). +\enditemize + + +For a detailed explanation of these parameters and how they influence +line breaking, you should consult the {\TeX}book\cite{DK:texbook}; +\TeX's {\tt parshape} feature is currently not implemented. There are +default values for all of these parameters (see section~\secref{defaults}), +and therefore it might not be necessary to specify any of them. +Any local adjustments are contained in a list of +parameters contained in the paragraph node. + +A further complication arises from displayed\index{displayed formula} formulas +that interrupt a paragraph. Such displays are described in the next +section. + +To summarize, a paragraph node in the long format specifies an +extended dimension, a parameter list, +and a node list. The extended dimension is given either as an +|xdimen| node (info bit |b100|) or as a reference; similarly the parameter list +can be embedded in the node (info bit |b010|) or again it is given by a reference. + + +\readcode +@s PAR symbol +@s par symbol +@s xdimen_ref symbol +@s param_ref symbol +@s par_dimen symbol + + +@<symbols@>= +%token PAR "par" +%type <info> par +@ + +@<scanning rules@>= +::@=par@> :< return PAR; >: +@ + + +The following parsing rules are slightly more complicated than I would like them to be, but it seems more important +to achieve a regular layout of the short format nodes where all sub nodes are located at the end of a node. +In this case, I want to put a |param_ref| before an |xdimen| node, but otherwise have +the |xdimen_ref| before a |param_list|. +The |par_dimen| rule is introduced only to avoid a reduce/reduce conflict in the parser. +The parsing of |empty_param_list| and |non_empty_param_list| is explained in +section~\secref{paramlist}. + +@<parsing rules@>= +par_dimen: xdimen { hput_xdimen_node(&($1)); }; +par: xdimen_ref param_ref list {$$=b000;} + | xdimen_ref empty_param_list non_empty_param_list list { $$=b010;} + | xdimen_ref empty_param_list list { $$=b010;} + | xdimen param_ref { hput_xdimen_node(&($1)); } list { $$=b100;} + | par_dimen empty_param_list non_empty_param_list list { $$=b110;} + | par_dimen empty_param_list list { $$=b110;}; + +content_node: start PAR par END { hput_tags($1,TAG(par_kind,$3));}; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(par_kind,b000): @+HGET_PAR(b000);@+break; +case TAG(par_kind,b010): @+HGET_PAR(b010);@+break; +case TAG(par_kind,b100): @+HGET_PAR(b100);@+break; +case TAG(par_kind,b110): @+HGET_PAR(b110);@+break; +@ + +@<get macros@>= +#define @[HGET_PAR(I)@] @/\ +{ uint8_t n;\ + if ((I)==b100) {n=HGET8; @+REF(param_kind,n);@+}\ + if ((I)&b100) {xdimen_t x; @+hget_xdimen_node(&x); @+hwrite_xdimen(&x);@+} else HGET_REF(xdimen_kind);\ + if ((I)&b010) { list_t l; @+hget_param_list(&l); @+hwrite_param_list(&l); @+} \ + else if ((I)!=b100) HGET_REF(param_kind)@; else hwrite_ref(n);\ + { list_t l; @+hget_list(&l);@+ hwrite_list(&l); @+}} +@ + + +\subsection{Mathematics}\index{Mathematics}\index{displayed formula} +\gdef\subcodetitle{Displayed Math} +Being able to handle mathematics\index{mathematics} nicely is one +of the primary features of \TeX\ and +so you should expect the same from \HINT. +We start here with the more complex case---displayed equations---and finish with the +simpler case of mathematical formulas that are part of the normal flow of text. + +Displayed equations occur inside a paragraph\index{paragraph} +node. They interrupt normal processing of the paragraph and the +paragraph processing is resumed after the display. Positioning of the +display depends on several parameters, the shape of the paragraph, and +the length of the last line preceding the display. Displayed formulas +often feature an equation number which can be placed either left or +right of the formula. Also the size of the equation number will +influence the placement of the formula. + +In a \HINT\ file, the parameter list is followed by a list of content +nodes, representing the formula, and an optional horizontal box +containing the equation number. + +In the short format, we use the info bit |b100| to indicate the +presence of a parameter list (which might be empty---so it's actually the absence of a +reference to a parameter list); the info bit |b010| to indicate the presence of +a left equation number; and the info bit |b001| for a right +equation\index{equation number} number. + +In the long format, we use ``{\tt eqno}'' or ``{\tt left eqno}'' to indicate presence and +placement of the equation number. + +\readcode +@s MATH symbol +@s math symbol +@<symbols@>= +%token MATH "math" +%type <info> math +@ + +@<scanning rules@>= +::@=math@> :< return MATH; >: +@ + +@<parsing rules@>= +math: param_ref list {$$=b000;} + | param_ref list hbox_node {$$=b001;} + | param_ref hbox_node list {$$=b010;} + | empty_param_list list {$$=b100;} + | empty_param_list list hbox_node {$$=b101;} + | empty_param_list hbox_node list {$$=b110;} + | empty_param_list non_empty_param_list list {$$=b100;} + | empty_param_list non_empty_param_list list hbox_node {$$=b101;} + | empty_param_list non_empty_param_list hbox_node list {$$=b110;}; + +content_node: start MATH math END @/{ hput_tags($1,TAG(math_kind,$3));}; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(math_kind,b000): HGET_MATH(b000); @+ break; +case TAG(math_kind,b001): HGET_MATH(b001); @+ break; +case TAG(math_kind,b010): HGET_MATH(b010); @+ break; +case TAG(math_kind,b100): HGET_MATH(b100); @+ break; +case TAG(math_kind,b101): HGET_MATH(b101); @+ break; +case TAG(math_kind,b110): HGET_MATH(b110); @+ break; +@ + +@<get macros@>= +#define @[HGET_MATH(I)@] \ +if ((I)&b100) { list_t l; @+hget_param_list(&l); @+hwrite_param_list(&l); @+} \ +else HGET_REF(param_kind);\ +if ((I)&b010) hget_hbox_node(); \ +{ list_t l; @+hget_list(&l);@+ hwrite_list(&l); @+} \ +if ((I)&b001) hget_hbox_node(); +@ + +\gdef\subcodetitle{Text Math} +Things are much simpler if mathematical formulas are embedded in regular text. +Here it is just necessary to mark the beginning and the end of the formula +because glue inside a formula is not a possible point for a line break. +To break the line within a formula you can insert a penalty node. + +In the long format, such a simple math node just consists of the keyword ``on'' +or ``off''. In the short format, there are two info values still unassigned: +we use |b011| for ``off'' and |b111| for ``on''. + + +\readcode +@s ON symbol +@s OFF symbol +@s on_off symbol +@<symbols@>= +%token ON "on" +%token OFF "off" +%type <i> on_off +@ + +@<scanning rules@>= +::@=on@> :< return ON; >: +::@=off@> :< return OFF; >: +@ + +@<parsing rules@>= +on_off: ON {$$=1;} | OFF {$$=0;}; +math: on_off { $$=b011|($1<<2); }; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(math_kind,b111): hwritef(" on");@+break; +case TAG(math_kind,b011): hwritef(" off");@+break; +@ + +Note that \TeX\ allows math nodes to specify a width using the current value of +mathsurround. If this width is nonzero, it is equivalent to inserting a +kern node before the math on node and after the math off node. + +\subsection{Adjustments}\label{adjust} +An adjustment\index{adjustment} occurs only in paragraphs\index{paragraph}. +When the line breaking\index{line breaking} routine finds an adjustment, it inserts +the vertical material contained in the adjustment node right after the current line. +Adjustments simply contain a list node. + +\vbox{\readcode\vskip -\baselineskip\putcode} +@s ADJUST symbol +@<symbols@>= +%token ADJUST "adjust" +@ + +@<scanning rules@>= +::@=adjust@> :< return ADJUST; >: +@ + +@<parsing rules@>= +content_node: start ADJUST list END { hput_tags($1,TAG(adjust_kind,1));}; +@ + +\vbox{\getcode\vskip -\baselineskip\writecode} +@<cases to get content@>= +@t\1\kern1em@> +case TAG(adjust_kind,1):@+ { list_t l;@+hget_list(&l); @+ hwrite_list(&l); @+} @+ break; +@ + +\subsection{Tables}\index{alignment} +As long as a table contains no dependencies on \.{hsize} and \.{vsize}, +Hi\TeX\ can expand an alignment into a set of nested horizontal and +vertical boxes and no special processing is required. +As long as only the size of the table itself but neither the tabskip +glues nor the table content depends on \.{hsize} or \.{vsize}, the table +just needs an outer node of type |hset_kind| or |vset_kind|. If there +is non aligned material inside the table that depends on \.{hsize} or +\.{vsize}, a vpack or hpack node is still sufficient. + +While it is reasonable to restrict the tabskip glues to be ordinary +glue values without \.{hsize} or \.{vsize} dependencies, it might be +desirable to have content in the table that does depend on \.{hsize} or +\.{vsize}. For the latter case, we need a special kind of table +node. Here is why: + +As soon as the dimension of an item in the table is an extended +dimension, it is no longer possible to compute the maximum natural with +of a column, because it is not possible to compare extended dimensions +without knowing \.{hsize} and \.{vsize}. Hence the computation of maximum +widths needs to be done in the viewer. After knowing the width of the columns, +the setting of tabskip glues is easy to compute. + +To implement these extended tables, we will need a table node that +specifies a direction, either horizontal or vertical; a list of +tabskip glues, with the provision that the last tabskip glue in the +list is repeated as long as necessary; and a list of table content. +The table's content is stacked, either vertical or +horizontal, orthogonal to the alignment direction of the table. +The table's content consists of nonaligned content, for example extra glue +or rules, and aligned content. +Each element of aligned content +is called an outer item and it consist of a list of inner items. +For example in a horizontal alignment, each row is an outer item +and each table entry in that row is an inner item. +An inner item contains a box node (of kind |hbox_kind|, |vbox_kind|, +|hset_kind|, |vset_kind|, |hpack_kind|, or |vpack_kind|) followed by +an optional span count. + +The glue of the boxes in the inner items will be reset so that all boxes in the same +column reach the same maximum column with. The span counts will be replaced by +the appropriate amount of empty boxes and tabskip glues. Finally the +glue in the outer item will be set to obtain the desired size +of the table. + +The definitions below specify just a |list| for the list of tabskip glues and a +list for the outer table items. +This is just for convenience; the first list must contain glue +nodes and the second list must contain nonaligned content and inner item nodes. + +We reuse the |H| and |V| tokens, defined as part of the specification +of extended dimensions, to indicate the alignment direction of the +table. To tell a reference to an extended dimension from a reference +to an ordinary dimension, we prefix the former with an |XDIMEN| token; +for the latter, the |DIMEN| token is optional. The scanner will +recognize not only ``item'' as an |ITEM| token but also ``row'' and +''column''. This allows a more readable notation, for example by +marking the outer items as rows and the inner items as columns. + +In the short format, the |b010| bit is used to mark a vertical table +and the |b101| bits indicate how the table size is specified; an outer +item node has the info value |b000|, an inner item node with info +value |b111| contains an extra byte for the span count, otherwise the +info value is equal to the span count. + + + + + + +\readcode +@s TABLE symbol +@s ITEM symbol +@s table symbol +@s span_count symbol + +@<symbols@>= +%token TABLE "table" +%token ITEM "item" +%type <info> table span_count +@ + +@<scanning rules@>= +::@=table@> :< return TABLE; >: +::@=item@> :< return ITEM; >: +::@=row@> :< return ITEM; >: +::@=column@> :< return ITEM; >: +@ + +@<parsing rules@>= +span_count: UNSIGNED { $$=hput_span_count($1); }; +content_node: start ITEM content_node END { hput_tags($1,TAG(item_kind,1)); }; +content_node: start ITEM span_count content_node END {@+ hput_tags($1,TAG(item_kind,$3));}; +content_node: start ITEM list END { hput_tags($1,TAG(item_kind,b000));}; + +table: H box_goal list list {$$=$2;}; +table: V box_goal list list {$$=$2|b010;}; + +content_node: start TABLE table END { hput_tags($1,TAG(table_kind,$3));}; +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(table_kind,b000): @+ HGET_TABLE(b000); @+ break; +case TAG(table_kind,b001): @+ HGET_TABLE(b001); @+ break; +case TAG(table_kind,b010): @+ HGET_TABLE(b010); @+ break; +case TAG(table_kind,b011): @+ HGET_TABLE(b011); @+ break; +case TAG(table_kind,b100): @+ HGET_TABLE(b100); @+ break; +case TAG(table_kind,b101): @+ HGET_TABLE(b101); @+ break; +case TAG(table_kind,b110): @+ HGET_TABLE(b110); @+ break; +case TAG(table_kind,b111): @+ HGET_TABLE(b111); @+ break;@# + +case TAG(item_kind,b000): @+{@+ list_t l;@+ hget_list(&l);@+ hwrite_list(&l);@+ } @+ break; +case TAG(item_kind,b001): hget_content_node(); @+ break; +case TAG(item_kind,b010): hwritef(" 2");@+hget_content_node(); @+ break; +case TAG(item_kind,b011): hwritef(" 3");@+hget_content_node(); @+ break; +case TAG(item_kind,b100): hwritef(" 4");@+hget_content_node(); @+ break; +case TAG(item_kind,b101): hwritef(" 5");@+hget_content_node(); @+ break; +case TAG(item_kind,b110): hwritef(" 6");@+hget_content_node(); @+ break; +case TAG(item_kind,b111): hwritef(" %u",HGET8);@+hget_content_node(); @+ break; +@ + +@<get macros@>= +#define @[HGET_TABLE(I)@] \ +if(I&b010) hwritef(" v"); @+else hwritef(" h"); \ +if ((I)&b001) hwritef(" add");@+ else hwritef(" to");\ +if ((I)&b100) {xdimen_t x; hget_xdimen_node(&x); @+hwrite_xdimen_node(&x);@+} else HGET_REF(xdimen_kind)@;\ +{@+ list_t l; @+hget_list(&l);@+ hwrite_list(&l);@+ } /* tabskip */ \ +{@+ list_t l; @+hget_list(&l);@+ hwrite_list(&l);@+ } /* items */ +@ + + +\putcode +@<put functions@>= +info_t hput_span_count(uint32_t n) +{ if (n==0) QUIT("Span count in item must not be zero"); + else if (n<7) return n; + else if (n>0xFF) QUIT("Span count %d must be less than 255",n); + else + { HPUT8(n); return 7; } +} +@ +\section{Extensions to \TeX}\hascode + +\subsection{Images} +Images behave pretty much like glue\index{glue}. They can stretch (or shrink) +together with the surrounding glue to fill a horizontal or vertical box. +Like glue, they stretch in the horizontal direction when filling an horizontal box +and they stretch in the vertical direction as part of a vertical box. +Stretchability and shrinkability are optional parts of an image node. + +Unlike glue, images have both a width and a height. +The relation of height to width, the aspect ratio, is preserved by stretching and shrinking. + +While glue often has a zero width, images usually have a nonzero natural size and making +them much smaller is undesirable. +The natural width and height of an image are optional parts of an image node; +typically this information is contained in the image data. + +The only required part of an image node is the number of the auxiliary section +where the image data can be found. + +@<hint types@>= +typedef struct {@+ +uint16_t n;@+ +dimen_t w,h;@+ +stretch_t p,m;@+ +} image_t; +@ + + +\readcode +@s IMAGE symbol +@s image symbol +@s image_dimen symbol +@<symbols@>= +%token IMAGE "image" +%type <x> image image_dimen +@ + +@<scanning rules@>= +::@=image@> :< return IMAGE; >: +@ + +@<parsing rules@>= +image_dimen: dimension dimension {$$.w=$1; $$.h=$2;} | {$$.w=$$.h=0; }; +image: UNSIGNED image_dimen plus minus { $$.w=$2.w; $$.h=$2.h; $$.p=$3; $$.m=$4; RNG("Section number",$1,3,max_section_no);$$.n=$1; }; +content_node: start IMAGE image END { hput_tags($1,hput_image(&($3)));} +@ + +\writecode +@<write functions@>= +void hwrite_image(image_t *x) +{ hwritef(" %u",x->n); + if (x->w!=0 ||x->h!=0) { hwrite_dimension(x->w); hwrite_dimension(x->h);@+} + hwrite_plus(&x->p); + hwrite_minus(&x->m); +} +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(image_kind,b100): @+ { image_t x;@+HGET_IMAGE(b100,x);@+}@+break; +case TAG(image_kind,b101): @+ { image_t x;@+HGET_IMAGE(b101,x);@+}@+break; +case TAG(image_kind,b110): @+ { image_t x;@+HGET_IMAGE(b110,x);@+}@+break; +case TAG(image_kind,b111): @+ { image_t x;@+HGET_IMAGE(b111,x);@+}@+break; +@ + +@<get macros@>= +#define @[HGET_IMAGE(I,X)@] @/\ +HGET16((X).n);RNG("Section number",(X).n,3,max_section_no); \ +if (I&b010) {HGET32((X).w);HGET32((X).h);@+} \ +else (X).w=(X).h=0;\ +if (I&b001) {HGET_STRETCH((X).p);HGET_STRETCH((X).m);@+}\ +else { (X).p.f=(X).m.f=0.0; (X).p.o=(X).m.o=normal_o;@+}\ +hwrite_image(&(X)); +@ + + +\putcode +@<put functions@>= +uint8_t hput_image(image_t *x) +{ info_t i=b100; + HPUT16(x->n); + if (x->w!=0 || x->h!=0)@+ {HPUT32(x->w); HPUT32(x->h); i|=b010;@+ } + if (x->p.f!=0.0 || x->m.f!=0.0)@+ {hput_stretch(&x->p); hput_stretch(&x->m); i|=b001;@+ } + return TAG(image_kind,i); +} +@ + + +\subsection{Positions, Outlines, Links, and Labels}\label{labels} +\index{position}\index{outline}\index{link}\index{label} +A viewer can usually not display the entire content section of +a \HINT\ file. Instead it will display a page of content and will give +its user various means to change the page. This might be as simple as +a ``page down'' or ``page up'' button (or gesture) and as +sophisticated as searching using regular expressions. More +traditional ways to navigate the content include the use of a table of +content or an index of keywords. All these methods of changing a page +have in common that a part of the content that fits nicely in the +screen area provided by the output device must be rendered given a +position inside the content section. + + +Let's assume that the viewer uses a \HINT\ file in short +format---after all that's the format designed for precisely this use. +A position inside the content section is then the position of the +starting byte of a node. Such a position can be stored as a 32 bit +number. Because even the smallest node contains two tag bytes, +the position of any node is strictly smaller than the maximum 32 bit +number which we can conveniently use as a ``non position''. + +@<hint macros@>= +#define HINT_NO_POS 0xFFFFFFFF +@ + +To render a page starting at a given position is not difficult: +We just read content nodes, starting at the given position and feed +them to \TeX's page builder until the page is complete. To implement a +``clickable'' table of content this is good enough. We store with +every entry in the table of content the position of the section +header, and when the user clicks the entry, the viewer can display a +new page starting exactly with that section header. + +Things are slightly more complex if we want to implement a ``page +down'' button. If we press this button, we want the next page to +start exactly where the current page has ended. This is +typically in the middle of a paragraph node, and it might even be in +the middle of an hyphenated word in that paragraph. Fortunately, +paragraph and table nodes are the only nodes that can be broken across page +boundaries. But broken paragraph nodes are a common case non the less, +and unless we want to search for the enclosing node, we need to +augment in this case the primary 32 bit position inside the content +section with a secondary position. Most of the +time, 16 bit will suffice for this secondary position if we give it +relative to the primary position. Further, if the list of nodes forming the +paragraph is given as a text, we need to know the current font at the +secondary position. Of course, the viewer can find it by scanning the +initial part of the text, but when we think of a page down button, the +viewer might already know it from rendering the previous page. + +Similar is the case of a ``page up'' button. Only here we need a page +that ends precisely where our current page starts. Possibly even with +the initial part of a hyphenated word. Here we need a reverse version +of \TeX's page builder that assembles a ``good'' page from the bottom +up instead of from the top down. Sure the viewer can cache the start +position of the previous page (or the rendering of the entire page) if +the reader has reached the current page using the page down +button. But this is not possible in all cases. The reader might have +reached the current page using the table of content or even an index +or a search form. + +This is the most complex case to consider: a link from an index or a +search form to the position of a keyword in the main text. Let's assume +someone looks up the word ``M\"unchen''. Should the viewer then +generate a page that starts in the middle of a sentence with the word +``M\"unchen''? Probably not! We want a page that shows at least the whole sentence if +not the whole paragraph. Of course the program that generates the +link could specify the position of the start of the paragraph instead +of the position of the word. But that will not solve the problem. Just +imagine reading the groundbreaking masterpiece of a German philosopher +on a small hand-held device: the paragraph will most likely be very +long and perhaps only part of the first sentence will fit on the small +screen. So the desired keyword might not be found on the page that +starts with the beginning of the paragraph; it might not even be on +the next or next to next page. Only the viewer can decide what is the +best fragment of content to display around the position of the given +keyword. + +To summarize, we need three different ways to render a page for a given position: +\itemize +\item A page that starts exactly at the given position. +\item A page that ends exactly at the given position. +\item The ``best'' page that contains the given position somewhere in the middle. +\enditemize + +\noindent +A possible way to find the ``best'' page for the latter case +could be the following: +\itemize +\item If the position is inside a paragraph, break the paragraph + into lines. One line will contain + the given position. Let's call this the destination line. +\item If the paragraph will not fit entirely on the page, + start the page with the beginning of the + paragraph if that will place the destination line on the page, otherwise + start with a line in the paragraph that is about half a page + before the destination line. +\item Else traverse the content list backward for about $2/3$ of the + page height and forward for about $2/3$ of the page height, searching + for the smallest negative penalty node. Use the penalty node found as + either the beginning or ending of the page. +\item If there are several equally low negative penalty nodes. Prefer + penalties preceding the destination line over penalty nodes following + it. A good page start is more important than a good page end. +\item If there are are still several equally low negative penalty + nodes, choose the one whose distance to the destination line is closest + to $1/2$ of the page height. +\item If no negative penalty nodes could be found, start the page with + the paragraph containing the destination line. +\item Once the page start (or end) is found, use \TeX's page builder + (or its reverse variant) to complete the page. +\enditemize + +We call content nodes that reference some position inside the content section +``link'' nodes. The position that is referenced is called the destination of the link. +Link nodes occur always in pairs of an ``on'' link +followed by a corresponding ``off'' link that both reference the same position +%, the same nesting level, % not sure! +and no other link nodes between them. +The content between the two will constitute the visible part of the link. + +To encode a position inside the content section that can be used +as the destination of a link node, an other kind of node is needed which +we call a ``label''. + +Links are not the only way to navigate inside a large +document. The user interface can also present an ``outline'' +of the document that can be used for navigation. +An outline node implements an association between a name displayed by the +user interface of the \HINT\ viewer and the destination position in the \HINT\ document. + +It is possible though that outline nodes, link nodes, and label nodes can share +the same kind-value and we have |outline_kind==link_kind==label_kind|. +To distinguish an outline node from a label node---both occur +in the short format definition section---the |b100| info bit is set in an +outline node. + + +@<get functions@>= +void hget_outline_or_label_def(info_t i, uint32_t node_pos) +{ @+if (i&b100) + @<get and write an outline node@>@; + else + @<get and store a label node@>@; +} +@ + +The next thing we need to implement is a new maximum number +for outline nodes. We store this number in the variable +|max_outline| and limit it to a 16 bit value. + +In the short format, the value of |max_outline| is stored with the +other maximum values using the kind value |outline_kind==label_kind| and the info +value |b100| for single byte and |b101| for a two byte value. + +\codesection{\getsymbol}{Reading the Short Format}\getindex{1}{7}{Special Maximum Values} +@<cases of getting special maximum values@>= +@t\1\kern1em@> +case TAG(outline_kind,b100): +case TAG(outline_kind,b101): max_outline=n; + DBG(DBGDEF|DBGLABEL,"max(outline) = %d\n",max_outline); break; +@ + +\codesection{\putsymbol}{Writing the Short Format}\putindex{1}{7}{Special Maximum Values} +@<cases of putting special maximum values@>= +if (max_outline>-1) +{ uint32_t pos=hpos++-hstart; + DBG(DBGDEF|DBGLABEL,"max(outline) = %d\n",max_outline); + hput_tags(pos,TAG(outline_kind,b100|(hput_n(max_outline)-1))); +} +@ + +\codesection{\wrtsymbol}{Writing the Long Format}\wrtindex{1}{7}{Special Maximum Values} +@<cases of writing special maximum values@>= +@t\1\kern1em@> +case label_kind: +if (max_ref[label_kind]>-1)@/ +{ hwrite_start(); + hwritef("label %d",max_ref[label_kind]); + hwrite_end();@+ +} +if (max_outline>-1)@/ +{ hwrite_start(); + hwritef("outline %d", max_outline); + hwrite_end();@+ +} +break; +@ + +\codesection{\redsymbol}{Reading the Long Format}\redindex{1}{7}{Special Maximum Values} +@<parsing rules@>= +max_value: OUTLINE UNSIGNED { max_outline=$2; + RNG("max outline",max_outline,0, 0xFFFF); + DBG(DBGDEF|DBGLABEL,"Setting max outline to %d\n",max_outline); + }; +@ + +After having seen the maximum values, we now explain labels, then links, +and finally outlines. + + +To store labels, we define a data type |label_t| and an array |labels| +indexed by the labels reference number. + +@<hint basic types@>= +typedef struct +{@+ uint32_t pos; /* position */ + uint8_t where; /* where on the rendered page */ + bool used; /* label used in a link or an outline */ + int next; /* reference in a linked list */ + uint32_t pos0;@+ uint8_t f; /* secondary position */ +} label_t; +@ + +The |where| field indicates where the label position +should be on the rendered page: at the top, +at the bottom, or somewhere in the middle. +An undefined label has |where| equal to zero. + +@<hint macros@>= +#define LABEL_UNDEF 0 +#define LABEL_TOP 1 +#define LABEL_BOT 2 +#define LABEL_MID 3 +@ + +@<common variables@>= +label_t *labels; +int first_label=-1; +@ +The variable |first_label| will be used together with the |next| field of +a label to construct a linked list of labels. + +@<initialize definitions@>= +if (max_ref[label_kind]>=0)@/ + ALLOCATE(labels,max_ref[label_kind]+1,label_t); +@ + +The implementation of labels has to solve the +problem of forward links: +a link node that references a label +that is not yet defined. +We solve this problem by +keeping all labels in the definition section. +So for every label at least a definition is available +before we start with the content section and we can fill +in the position when the label is found. +If we restrict labels to the definition section and +do not have an alternative representation, the number of possible references +is a hard limit on the number of labels in a document. +Therefore label references are allowed to use 16 bit reference numbers. +In the short format, +the |b001| bit indicates a two byte reference number if set, and a one byte +reference number otherwise. + +In the short format, the complete information about a label is in the definition section. +In the long format, this is not possible because we do not have node positions. +Therefore we will put label nodes at appropriate points in the content section +and compute the label position when writing the short format. + +\gdef\subcodetitle{Labels} +\readcode +@s LABEL symbol +@s BOT symbol +@s MID symbol +@s placement symbol + +@<symbols@>= +%token LABEL "label" +%token BOT "bot" +%token MID "mid" +%type <i> placement +@ + +@<scanning rules@>= +::@=label@> :< return LABEL; >: +::@=bot@> :< return BOT; >: +::@=mid@> :< return MID; >: +@ + +A label node specifies the reference number and a placement. + +@<parsing rules@>= +placement: TOP {$$=LABEL_TOP;} | BOT {$$=LABEL_BOT;} | MID {$$=LABEL_MID;} | {$$=LABEL_MID;}; +content_node: START LABEL REFERENCE placement END @| + { hset_label($3,$4); @+} +@ + + +After parsing a label, the function |hset_label| is called. + +@<put functions@>= +void hset_label(int n,int w ) +{ label_t *t; + REF_RNG(label_kind,n); + t=labels+n;@/ + if (t->where!=LABEL_UNDEF) + MESSAGE("Duplicate definition of label %d\n",n); + t->where=w; + t->pos=hpos-hstart; + t->pos0=hpos0-hstart; + t->next=first_label; first_label=n; +} +@ + + +All that can be done by the above function +is storing the data obtained in the |labels| array. +The generation of the short format output is +postponed until the entire content section has been parsed and +the positions of all labels are known. + +One more complication needs to be considered: The |hput_list| function +is allowed to move lists in the output stream and if positions +inside the list were recorded in a label, these labels need an +adjustment. To find out quickly if any labels are affected, +the |hset_label| function +constructs a linked list of labels starting with the reference number +of the most recent label in |first_label| and the +reference number of the label preceding label |i| in |labels[i].next|. +Because labels are recorded with increasing positions, +the list will be sorted with positions decreasing. + +@<adjust label positions after moving a list@>= +{ int i; + for (i=first_label;i>=0 && labels[i].pos>=l->p;i=labels[i].next) + { DBG(DBGNODE|DBGLABEL,"Moving label *%d by %d\n", i,d);@/ + labels[i].pos+=d; + if (labels[i].pos0>=l->p) labels[i].pos0+=d; + } +} +@ + + +The |hwrite_label| function\label{hwritelabel} is the reverse of the above parsing rule. +Note that it is different from the +usual |hwrite_|\dots\ functions. And we will see shortly why that is so. + +%see |hwrite_range| +\writecode +@<write functions@>= +void hwrite_label(void) /* called in |hwrite_end| and at the start of a list */ +{@+ while (first_label>=0 && (uint32_t)(hpos-hstart)>=labels[first_label].pos)@/ + { label_t *t=labels+first_label; + DBG(DBGLABEL,"Inserting label *%d\n", first_label); + hwrite_start(); + hwritef("label *%d",first_label); + if (t->where==LABEL_TOP) hwritef(" top"); + else if (t->where==LABEL_BOT) hwritef(" bot"); + nesting--;hwritec('>'); /* avoid a recursive call to |hwrite_end| */ + first_label=labels[first_label].next; + } +} +@ + +The short format specifies the label positions in the definition section. +This is not possible in the long format because there are no ``positions'' +in the long format. Therefore long format label nodes must +be inserted in the content section just before those nodes +that should come after the label. The function |hwrite_label| is called +in |hwrite_end|. At that point |hpos| is the position of the next node +and it can be compared with the positions of the labels taken from +the definition section. +Because |hpos| is strictly increasing while reading the content section, +the comparison can be made efficient by sorting the labels. +The sorting uses the |next| field in the +array of |labels| to construct a linked list. After sorting, the value of +|first_label| is the index of the label with the smallest position; +and for each |i|, the value of |labels[i].next| is the index of +the label with the next bigger position. If |labels[i].next| is negative, +there is no next bigger position. +Currently a simple insertion sort is used. +The insertion sort will work well if the labels are already +mostly in ascending order. +If we expect lots of labels in random order, +a more sophisticated sorting algorithm might be appropriate. + + + +@<write functions@>= +void hsort_labels(void) +{ int i; + if (max_ref[label_kind]<0) + { first_label=-1; return; @+} /* empty list */ + first_label=max_ref[label_kind]; + while (first_label>=0 && labels[first_label].where==LABEL_UNDEF) + first_label--; + if (first_label<0) return; /* no defined labels */ + labels[first_label].next=-1; + DBG(DBGLABEL,"Sorting %d labels\n",first_label+1); + for (i=first_label-1; i>=0; i--) /* insert label |i| */ + if (labels[i].where!=LABEL_UNDEF)@/ + { uint32_t pos=labels[i].pos; + if (labels[first_label].pos >= pos)@/ + { labels[i].next= first_label; first_label=i;@+ } /* new smallest */ + else @/ + { int j; + for (j= first_label; + labels[j].next>=0 && labels[labels[j].next].pos<pos; + j=labels[j].next) continue; + labels[i].next=labels[j].next; labels[j].next=i; + } + } +} +@ + + +The following code is used to get label information from the +definition section and store it in the |labels| array. +The |b010| bit indicates the presence of a secondary position for the label. + +\getcode +@<get and store a label node@>= +{ label_t *t; + int n; + if (i&b001) HGET16(n); @+else n=HGET8; + REF_RNG(label_kind,n); + t=labels+n; + if (t->where!=LABEL_UNDEF) + DBG(DBGLABEL,"Duplicate definition of label %d at 0x%x\n",n, node_pos); + HGET32(t->pos); + t->where=HGET8; + if (t->where==LABEL_UNDEF || t->where>LABEL_MID) + DBG(DBGLABEL,"Label %d where value invalid: %d at 0x%x\n",n,t->where,node_pos); + if (i&b010) /* secondary position */ + { HGET32(t->pos0); t->f=HGET8;@+} + else t->pos0=t->pos; + DBG(DBGLABEL,"Defining label %d at 0x%x\n",n,t->pos); +} +@ + + +The function |hput_label| is simply the reverse of the above code. + +\putcode +@<put functions@>= +uint8_t hput_label(int n, label_t *l) +{ info_t i=b000; + HPUTX(13); + if (n>0xFF) {i|=b001; HPUT16(n);@+}@+ else HPUT8(n); + HPUT32(l->pos); + HPUT8(l->where); + if (l->pos!=l->pos0) + { i|=b010; HPUT32(l->pos0); HPUT8(l->f); @+} + return TAG(label_kind,i); +} +@ + +|hput_label_defs| is called by the parser after the entire content +section has been processed; it appends the label definitions +to the definition section. +%Using the fact that the linked list +%starting at |first_label| already contains all labels in +%order of descending position, we could easily output the +%labels in sorted order and reconstruct the sorting while reading +%in the labels. The \HINT\ format however does not require +%label nodes to be sorted and the |hsort_labels| function +%can not be avoided. +The outlines are stored after the labels because they reference the labels. +@<put functions@>= +extern void hput_definitions_end(void); +extern uint8_t hput_outline(outline_t *t); +void hput_label_defs(void) +{ int n; + section_no=1; + hstart=dir[1].buffer; + hend=hstart+ dir[1].bsize; + hpos=hstart+dir[1].size;@/ + @<output the label definitions@>@; + @<output the outline definitions@>@; + hput_definitions_end(); +} +@ + +@<output the label definitions@>= + for (n=0; n<=max_ref[label_kind]; n++)@/ + { label_t *l=labels+n; + uint32_t pos; + if (l->used)@/ + { pos=hpos++-hstart; + hput_tags(pos,hput_label(n,l)); + if (l->where==LABEL_UNDEF) + MESSAGE("WARNING: Label *%d is used but not defined\n",n); + else + DBG(DBGDEF|DBGLABEL,"Label *%d defined 0x%x\n",n,pos);@/ + } + else + { if (l->where!=LABEL_UNDEF) + { pos=hpos++-hstart; + hput_tags(pos,hput_label(n,l)); + DBG(DBGDEF|DBGLABEL,"Label *%d defined but not used 0x%x\n",n,pos);@/ + } + } + } +@ + +Links are simpler than labels. They are found only in the +content section and resemble pretty much what we have seen for other +content nodes. Let's look at them next. +When reading a short format link node, +we use again the |b001| info bit to indicate a 16 bit reference +number to a label. The |b010| info bit indicates an ``on'' link. +\gdef\subcodetitle{Links} +\getcode +@<get macros@>= +#define @[HGET_LINK(I)@] @/\ +{ int n; if (I&b001) HGET16(n);@+ else n=HGET8; @+ hwrite_link(n,I&b010); @+} +@ + +@<cases to get content@>= +@t\1\kern1em@> +case TAG(link_kind,b000): @+ HGET_LINK(b000);@+ break; +case TAG(link_kind,b001): @+ HGET_LINK(b001);@+ break; +case TAG(link_kind,b010): @+ HGET_LINK(b010);@+ break; +case TAG(link_kind,b011): @+ HGET_LINK(b011);@+ break; +@ + +The function |hput_link| will insert the link in the output stream and return +the appropriate tag. + +\putcode +@<put functions@>= +uint8_t hput_link(int n, int on) +{ info_t i; + REF_RNG(label_kind,n); + labels[n].used=true; + if (on) i=b010;@+ else i=b000; + if (n>0xFF) { i|=b001; HPUT16(n);@+} @+else HPUT8(n); + return TAG(link_kind,i); +} +@ + +\readcode +@s LINK symbol +@<symbols@>= +%token LINK "link" +@ +@<scanning rules@>= +::@=link@> :< return LINK; >: +@ + +@<parsing rules@>= +content_node:start LINK REFERENCE on_off END + {@+ hput_tags($1,hput_link($3,$4));@+ }; +@ + +\writecode +@<write functions@>= +void hwrite_link(int n, uint8_t on) +{ REF_RNG(label_kind,n); + if (labels[n].where==LABEL_UNDEF) + MESSAGE("WARNING: Link to an undefined label %d\n",n); + hwrite_ref(n); + if (on) hwritef(" on"); + else hwritef(" off"); +} +@ + +Now we look at the +outline nodes which are found only in the definition section. +Every outline node is associated with a label node, giving the position in the +document, and a unique title that should tell the user +what to expect when navigating to this position. For example +an item with the title ``Table of Content'' should navigate +to the page that shows the table of content. +The sequence of outline nodes found in the definition section +gets a tree structure by assigning to each item a depth level. + +@<hint types@>= +typedef struct {@+ +uint8_t *t; /* title */ +int s; /* title size */ +int d; /* depth */ +uint16_t r; /* reference to a label */ +} outline_t; +@ + +@<shared put variables@>= +outline_t *outlines; +@ + +@<initialize definitions@>= +if (max_outline>=0)@/ + ALLOCATE(outlines,max_outline+1,outline_t); +@ + +Child items follow their parent item and have a bigger depth level. +In the short format, the first item must be a root item, with +a depth level of 0. Further, if any item has the depth $d$, then the +item following it must have either the same depth $d$ in which +case it is a sibling, or the depth $d+1$ in which case it is a child, +or a depth $d^\prime$ with $0\le d^\prime<d$ in which case it is a sibling +of the latest ancestor with depth $d^\prime$. Because the depth is +stored in a single byte, the maximum depth is |0xFF|. + +In the long format, the depth assignments are more flexible. +We allow any signed integer, but insist that the depth +assignments can be compressed to depth levels for the +short format using the following algorithm: + +@<compress long format depth levels@>= +n=0;@+ +while (n<=max_outline) + n=hcompress_depth(n,0); +@ +Outline items must be listed in the order +in which they should be displayed. +The function |hcompress_depth(n,c)| will compress the subtree starting at +|n| with root level |d| to a new tree with the same structure +and root level |c|. It returns the outline number of the +following subtree. + +@<put functions@>= +int hcompress_depth(int n, int c) +{ int d=outlines[n].d; + if (c>0xFF) + QUIT("Outline %d, depth level %d to %d out of range",n,d,c); + while (n<=max_outline) + if (outlines[n].d==d) + outlines[n++].d=c; + else if (outlines[n].d>d) + n=hcompress_depth(n,c+1); + else break; + return n; +} +@ + +For an outline node, the |b001| bit indicates a two byte reference to a label. +There is no reference number for an outline item itself: +it is never referenced anywhere in an \HINT\ file. + +\gdef\subcodetitle{Outlines} +\vbox{\getcode\vskip -\baselineskip\writecode} + +@<get and write an outline node@>= + { int r,d; + list_t l; + static int outline_no=-1; + hwrite_start();@+hwritef("outline"); + ++outline_no; + RNG("outline",outline_no, 0, max_outline); + if (i&b001) HGET16(r);@+ else r=HGET8; + REF_RNG(link_kind,r); + if (labels[r].where==LABEL_UNDEF)@/ + MESSAGE("WARNING: Outline with undefined label %d at 0x%x\n",@|r, node_pos); + hwritef(" *%d",r);@/ + d=HGET8; hwritef(" %d",d);@/ + hget_list(&l);hwrite_list(&l);@/ + hwrite_end(); + } +@ + +When parsing an outline definition in the long format, +we parse the outline title as a |list| which will +write the representation of the list to the output stream. +Writing the outline definitions, however, must be postponed +until the label have found their way into the definition +section. So we save the list's representation in the +outline node for later use and remove it again from the +output stream. + +\readcode +@s OUTLINE symbol + +@<symbols@>= +%token OUTLINE "outline" +@ + +@<scanning rules@>= +::@=outline@> :< return OUTLINE; >: +@ + +@<parsing rules@>= +def_node: START OUTLINE REFERENCE integer position list END { + static int outline_no=-1; + $$.k=outline_kind; $$.n=$3; + if ($6.s==0) QUIT("Outline with empty title in line %d",yylineno); + outline_no++; + hset_outline(outline_no,$3,$4,$5); + }; +@ + +@<put functions@>= +void hset_outline(int m, int r, int d, uint32_t pos) +{ outline_t *t; + RNG("Outline",m,0,max_outline); + t=outlines+m; + REF_RNG(label_kind,r); + t->r=r; + t->d=d; + t->s=hpos-(hstart+pos); + hpos=(hstart+pos); + ALLOCATE(t->t,t->s,uint8_t); + memmove(t->t,hpos,t->s); + labels[r].used=true; +} +@ +To output the title, we need to move the list back to the output stream. +Before doing so, we allocate space (and make sure there is room left for the +end tag of the outline node), and after doing so, we release +the memory used to save the title. + +@<output the title of outline |*t|@>= + memmove(hpos,t->t,t->s); + hpos=hpos+t->s; + free(t->t); +@ + +We output all outline definitions from 0 to |max_outline| and +check that every one of them has a title. Thereby we make sure +that in the short format |max_outline| matches the number of +outline definitions. + +\putcode +@<put functions@>= +uint8_t hput_outline(outline_t *t) +{ info_t i=b100; + HPUTX(t->s+4); + if (t->r>0xFF) {i|=b001; @+HPUT16(t->r);@+} @+else HPUT8(t->r); + labels[t->r].used=true; + HPUT8(t->d); + @<output the title of outline |*t|@>@; + return TAG(outline_kind,i); +} +@ + +@<output the outline definitions@>= +@<compress long format depth levels@>@; +for (n=0;n<=max_outline;n++) +{ outline_t *t=outlines+n; + uint32_t pos; + pos=hpos++-hstart; + if (t->s==0 || t->t==NULL) + QUIT("Definition of outline %d has an empty title",n); + DBG(DBGDEF|DBGLABEL,"Outline *%d defined\n",n);@/ + hput_tags(pos,hput_outline(t)); +} +@ + +\subsection{Colors} +Colors\index{color} are certainly one of the features you will find in the final \HINT\ file format. +Here some remarks must suffice. + +A \HINT\ viewer must be capable of rendering a page given just any valid +position inside the content section. Therefore \HINT\ files are stateless; +there is no need to search for preceding commands that might change a state +variable. +As a consequence, we can not just define a ``color change node''. +Colors could be specified as an optional parameter of a glyph node, but the +amount of data necessary would be considerable. In texts, on the other hand, +a color change control code would be possible because we parse texts only in forward +direction. The current font would then become a current color and font with the appropriate +changes for positions. + +A more attractive alternative would be to specify colored fonts. +This would require an optional +color argument for a font. For example one could have a cmr10 font in black as +font number 3, and a cmr10 font in blue as font number 4. Having 256 different fonts, +this is definitely a possibility because rarely you would need that many fonts +or that many colors. If necessary and desired, one could allow 16 bit font numbers +of overcome the problem. + +Background colors could be associated with boxes as an optional parameter. + + +\section{Replacing \TeX's Page Building Process} + +\TeX\ uses an output\index{output routine} routine to finalize the page. It uses the accumulated material +from the page builder, found in {\tt box255}, attaches headers, footers, and floating material +like figures, tables, and footnotes. The latter material is specified by insert nodes +while headers and footers are often constructed using mark nodes. +Running an output routine requires the full power of the \TeX\ engine and will not be +part of the \HINT\ viewer. Therefore, \HINT\ replaces output routines by page templates\index{template}. +As \TeX\ can use different output routines for different parts of a book---for example +the index might use a different output routine than the main body of text---\HINT\ +will allow multiple page templates. To support different output media, the page +templates will be named and a suitable user interface may offer the user a selection +of possible page layouts. In this way, the page layout remains in the hands of the +book designer, and the user has still the opportunity to pick a layout that best fits +the display device. + +\TeX\ uses insertions to describe floating content that is not necessarily displayed +where it is specified. Three examples may illustrate this: +\itemize +\item Footnotes\footnote*{Like this one.} are specified in the middle of the text but are displayed at the +bottom of the page. Several +footnotes\index{footnote} on the same page are collected and displayed together. The +page layout may specify a short rule to separate footnotes from the +main text, and if there are many short footnotes, it may use two columns +to display them. In extreme cases, the page layout may demand a long +footnote to be split and continued on the next page. + +\item Illustrations\index{illustration} may be displayed exactly where specified if there is enough +room on the page, but may move to the top of the page, the bottom of the page, +the top of next page, or a separate page at the end of the chapter. + +\item Margin notes\index{margin note} are displayed in the margin on the same page starting at the top +of the margin. +\enditemize + +\HINT\ uses page templates and content streams to achieve similar effects. +But before I describe the page building\index{page building} mechanisms of \HINT, let me summarize \TeX's page builder. + +\TeX's page builder ignores leading glue\index{glue}, kern\index{kern}, and penalty\index{penalty} nodes until the first +box\index{box} or rule\index{rule} is encountered; +whatsit\index{whatsit node} nodes do not really contribute anything to a page; mark\index{mark node} nodes are recorded for later use. +Once the first box, rule, or insert\index{insert node} arrives, \TeX\ makes copies of all parameters +that influence the page building process and uses these copies. These parameters +are the |page_goal| and the |page_max_depth|. Further, the variables +|page_total|, |page_shrink|, |page_stretch|, |page_depth|, +and {\it insert\_pe\-nal\-ties\/} are initialized to zero. +The top skip\index{top skip} adjustment is made +when the first box or rule arrives---possibly after an insert. + +Now the page builder accumulates material: normal material goes into {\tt box255}\index{box 255} and will change |page_total|, |page_shrink|, +|page_stretch|, and |page_depth|. The latter is adjusted so that +is does not exceed |page_max_depth|. + +The handling of inserts\index{insert node} is more complex. +\TeX\ creates an insert class using \.{newinsert}. This reserves a number $n$ +and four registers: {\tt box\hair$n$} for the inserted material, {\tt count\hair$n$} for the +magnification factor $f$, {\tt dimen\hair$n$} for the maximum size per page $d$, and {\tt skip\hair$n$} for the +extra space needed on a page if there are any insertions of class $n$. + +For example plain \TeX\ allocates $n=254$ for footnotes\index{footnote} and sets +{\tt count254} to~$1000$, {\tt dimen254} to 8in, and {\tt skip254} to {\tt \BS bigskipamount}. + +An insertion node will specify the insertion class $n$, some vertical material, +its natural height plus depth $x$, a {\it split\-\_top\-\_skip}, a {\it split\-\_max\_depth}, +and a {\it floa\-ting\-\_pe\-nal\-ty}. + + +Now assume that an insert node with subtype 254 arrives at the page builder. +If this is the first such insert, \TeX\ will decrease the |page_goal| +by the width of skip254 and adds its stretchability and shrinkability +to the total stretchability and shrinkability of the page. Later, +the output routine will add some space and the footnote rule to fill just that +much space and add just that much shrinkability and stretchability to the page. +Then \TeX\ will normally add the vertical material in the insert node to +box254 and decrease the |page_goal| by $x\times f/1000$. + +Special processing is required if \TeX\ detects that there is not enough space on +the current page to accommodate the complete insertion. +If already a previous insert did not fit on the page, simply the |floating_penalty| +as given in the insert node is added to the total |insert_penalties|. +Otherwise \TeX\ will test that the total natural height plus depth of box254 +including $x$ does not exceed the maximum size $d$ and that the +$|page_total| + |page_depth| + x\times f/1000 - |page_shrink| \le |page_goal|$. +If one of these tests fails, the current insertion +is split in such a way as to make the size of the remaining insertions just pass the tests +just stated. + +Whenever a glue node, or penalty node, or a kern node that is followed by glue arrives +at the page builder, it rates the current position as a possible end of the page based on +the shrinkability of the page and the difference between |page_total| and |page_goal|. +As the page fills, the page breaks tend to become better and better until the +page starts to get overfull and the page breaks get worse and worse until +they reach the point where they become |awful_bad|. At that point, +the page builder returns to the best page break found so far and fires up the +output routine. + +Let's look next at the problems that show up when implementing a replacement mechanism for \HINT. + +\enumerate +\item +An insertion node can not always specify its height $x$ because insertions may contain paragraphs that need +to be broken in lines and the height of a paragraph depends in some non obvious way on +its width. + +\item +Before the viewer can compute the height $x$, it needs to know the width of the insertion. Just imagine +displaying footnotes in two columns or setting notes in the margin. Knowing the width, it +can pack the vertical material and derive its height and depth. + +\item +\TeX's plain format provides an insert macro that checks whether there is still space +on the current page, and if so, it creates a contribution to the main text body, otherwise it +creates a topinsert. Such a decision needs to be postponed to the \HINT\ viewer. + +\item +\HINT\ has no output routines that would specify something like the space and the rule preceding the footnote. + +\item +\TeX's output routines have the ability to inspect the content of the boxes, +split them, and distribute the content over the page. +For example, the output routine for an index set in two column format might +expect a box containing index entries up to a height of $2\times\.{vsize}$. +It will split this box in the middle and display the top part in the left +column and the bottom part in the right column. With this approach, the +last page will show two partly filled columns of about equal size. + +\item +\HINT\ has no mark nodes that could be used to create page headers or footers. +Marks, like output routines, contain token lists and need the full \TeX\ interpreter +for processing them. Hence, \HINT\ does not support mark nodes. +\endenumerate + +Here now is the solution I have chosen for \HINT: + +Instead of output routines, \HINT\ will use page templates. +Page templates are basically vertical boxes with placeholders marking the +positions where the content of the box registers, filled by the page builder, +should appear. +To output the page, the viewer traverses the page template, +replaces the placeholders by the appropriate box content, and +sets the glue. Inside the page template, we can use insert nodes to act +as placeholders. + +It is only natural to treat the page's main body, the +inserts, and the marks using the same mechanism. We call this +mechanism a content stream\index{stream}. +Content streams are identified by a stream number in the range 0 to 254; +the number 255 is used to indicate an invalid stream number. +The stream number 0 is reserved for the main content stream; it is always defined. +Besides the main content stream, there are three types of streams: +\itemize +\item normal streams correspond to \TeX's inserts and accumulate content on the page, +\item first\index{first stream} streams correspond to \TeX's first marks and will contain only the first insertion of the page, +\item last\index{last stream} streams correspond to \TeX's bottom marks and will contain only the last insertion of the page, and +\item top\index{top stream} streams correspond to \TeX's top marks. Top streams are not yet implemented. +\enditemize + +Nodes from the content section are considered contributions to stream 0 except +for insert nodes which will specify the stream number explicitly. +If the stream is not defined or is not used in the current page template, its content is simply ignored. + +The page builder needs a mechanism to redirect contributions from one content +stream to another content stream based on the availability of space. +Hence a \HINT\ content stream can optionally specify a preferred stream number, +where content should go if there is still space available, a next stream number, +where content should go if the present stream has no more space available, and +a split ratio if the content is to be split between these two streams before +filling in the template. + +Various stream parameters govern the treatment of contributions to the stream +and the page building process. + +\itemize +\item The magnification factor $f$: Inserting a box of height $h$ to this stream will contribute $h\times f/1000$ +to the height of the page under construction. For example, a stream +that uses a two column format will have an $f$ value of 500; a stream +that specifies notes that will be displayed in the page margin will +have an $f$ value of zero. + +\item The height $h$: The extended dimension $h$ gives the maximum height this +stream is allowed to occupy on the current page. +To continue the previous example, a stream that will be split into two columns +will have $h=2\cdot\.{vsize}$ , and a stream that specifies +notes that will be displayed in the page margin will have +$h=1\cdot\.{vsize}$. You can restrict the amount of space occupied by +footnotes to the bottom quarter by setting the corresponding $h$ value +to $h=0.25\cdot\.{vsize}$. + +\item The depth $d$: The dimension $d$ gives the maximum depth this +stream is allowed to have after formatting. + +\item The width $w$: The extended dimension $w$ gives the width of this stream +when formatting its content. For example margin notes +should have the width of the margin less some surrounding space. + +\item The ``before'' list $b$: If there are any contributions to this +stream on the current page, the material in list $b$ +is inserted {\it before\/} the material from the stream itself. For +example, the short line that separates the footnotes from the main +page will go, together with some surrounding space, into the list~$b$. + +\item The top skip glue $g$: This glue is inserted between the material +from list $b$ and the first box of the stream, reduced +by the height of the first box. Hence it specifies the distance between +the material in $b$ and the first baseline of the stream content. + +\item The ``after'' list $a$: The list $a$ is treated like list $b$ but +its material is placed {\it after\/} the material from the stream itself. + +\item The ``preferred'' stream number $p$: If $p\ne 255$, it is the number of +the {\it preferred\/} stream. If stream $p$ has still +enough room to accommodate the current contribution, move the +contribution to stream $p$, otherwise keep it. For example, you can +move an illustration to the main content stream, provided there is +still enough space for it on the current page, by setting $p=0$. + +\item The ``next'' stream number $n$: If $n\ne 255$, it is the number of the +{\it next\/} stream. If a contribution can not be +accommodated in stream $p$ nor in the current stream, treat it as an +insertion to stream $n$. For example, you can move contributions to +the next column after the first column is full, or move illustrations +to a separate page at the end of the chapter. + +\item The split ratio\index{split ratio} $r$: If $r$ is positive, both $p$ and $n$ must +be valid stream numbers and contents is not immediately moved to stream $p$ or $n$ as described before. +Instead the content is kept in the stream itself until the current page is complete. +Then, before inserting the streams into the page template, the content of +this stream is formatted as a vertical box, the vertical box is +split into a top fraction and a bottom fraction in the ratio $r/1000$ +for the top and $(1000-r)/1000$ for the bottom, and finally the top +fraction is moved to stream $p$ and the bottom fraction to stream +$n$. You can use this feature for example to implement footnotes +arranged in two columns of about equal size. By collecting all the +footnotes in one stream and then splitting the footnotes with $r=500$ +before placing them on the page into a right and left column. Even +three or more columns can be implemented by cascades of streams using +this mechanism. +\enditemize + +\subsection{Stream Definitions} +\index{stream} +There are four types of streams: normal streams that work like \TeX's inserts; +and first, last, and top streams that work like \TeX's marks. +For the latter types, the long format uses a matching keyword and the +short format the two least significant info bits. All stream definitions +start with the stream number. +In definitions of normal streams after the number follows in this order +\itemize +\item the maximum insertion height, +\item the magnification factor, and +\item information about splitting the stream. + It consists of: a preferred stream, a next stream, and a split ratio. + An asterisk indicates a missing stream reference, in the + short format the stream number 255 serves the same purpose. +\enditemize +All stream definitions finish with +\itemize +\item the ``before'' list, +\item an extended dimension node specifying the width of the inserted material, +\item the top skip glue, +\item the ``after'' list, +\item and the total height, stretchability, and shrinkability of the material in + the ``before'' and ``after'' list. +\enditemize + +A special case is the stream definition for stream 0, the main content stream. +None of the above information is necessary for it so it is omitted. +Stream definitions, including the definition of stream 0, +occur only inside page template definitions\index{template} +where they occur twice in two different roles: +In the stream definition list, they define properties of the stream +and in the template they mark the insertion point (see section~\secref{page}). +In the latter case, stream nodes just contain the stream number. +Because a template looks like ordinary vertical material, +we like to use the same functions for parsing it. +But stream definitions are very different from stream content +nodes. To solve the problem for the long format, +the scanner will return two different tokens +when it sees the keyword ``{\tt stream}''. +In the definition section, it will return +|STREAMDEF| and in the content section |STREAM|. +The same problem is solved in the short format +by using the |b100| bit to mark a definition. + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + +@s STREAM symbol +@s STREAMDEF symbol +@s TOP symbol +@s FIRST symbol +@s LAST symbol +@s NOREFERENCE symbol +@s stream_type symbol +@s stream_info symbol +@s stream_split symbol +@s stream_link symbol +@s stream_def_node symbol +@s stream_ins_node symbol +@s stream_ref symbol + + +@<symbols@>= +%token STREAM "stream" +%token STREAMDEF "stream (definition)" +%token FIRST "first" +%token LAST "last" +%token TOP "top" +%token NOREFERENCE "*" +%type <info> stream_type +%type <u> stream_ref +%type <rf> stream_def_node +@ + +@<scanning rules@>= +::@=stream@> :< if (section_no==1) return STREAMDEF; else return STREAM;@+ >: +::@=first@> :< return FIRST; >: +::@=last@> :< return LAST; >: +::@=top@> :< return TOP; >: +::@=\*@> :< return NOREFERENCE; >: +@ + +@<parsing rules@>= +stream_link: ref { REF_RNG(stream_kind,$1); } | NOREFERENCE {HPUT8(255);}; +stream_split: stream_link stream_link UNSIGNED @/{RNG("split ratio",$3,0,1000); HPUT16($3);}; +stream_info: xdimen_node UNSIGNED @/{RNG("magnification factor",$2,0,1000); HPUT16($2);} stream_split; + +stream_type: stream_info {$$=0;} |FIRST {$$=1;} @+ | LAST {$$=2;} @+ |TOP {$$=3;} ; + +stream_def_node: start STREAMDEF ref stream_type @/ + list xdimen_node glue_node list glue_node END @/ + {@+ DEF($$,stream_kind,$3); @+ hput_tags($1,TAG(stream_kind,$4|b100));}; + +stream_ins_node: start STREAMDEF ref END@/ + { RNG("Stream insertion",$3,0,max_ref[stream_kind]); hput_tags($1,TAG(stream_kind,b100));}; + +content_node: stream_def_node @+ | stream_ins_node; +@ + + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} + + + +@<get stream information for normal streams@>= +{ xdimen_t x; + uint16_t f,r; + uint8_t n; + DBG(DBGDEF,"Defining normal stream %d at " SIZE_F "\n",*(hpos-1),hpos-hstart-2); + hget_xdimen_node(&x); @+hwrite_xdimen_node(&x); + HGET16(f); @+RNG("magnification factor",f,0,1000);@+ hwritef(" %d",f); + n=HGET8; if (n==255) hwritef(" *"); else { REF_RNG(stream_kind,n);@+hwrite_ref(n);@+} + n=HGET8; if (n==255) hwritef(" *"); else { REF_RNG(stream_kind,n);@+hwrite_ref(n);@+} + HGET16(r); RNG("split ratio",r,0,1000); hwritef(" %d",r); +} +@ + +@<get functions@>= +static bool hget_stream_def(void) +{@+ if (KIND(*hpos)!=stream_kind || !(INFO(*hpos)&b100)) + return false; + else + { ref_t df; + @<read the start byte |a|@>@; + DBG(DBGDEF,"Defining stream %d at " SIZE_F "\n",*hpos,hpos-hstart-1); + DEF(df,stream_kind,HGET8); + hwrite_start();@+hwritef("stream");@+@+hwrite_ref(df.n); + if (df.n>0) + { xdimen_t x; @+ list_t l; + if (INFO(a)==b100) @<get stream information for normal streams@>@; + else if (INFO(a)==b101) hwritef(" first"); + else if(INFO(a)==b110) hwritef(" last"); + else if (INFO(a)==b111) hwritef(" top"); + hget_list(&l);@+ hwrite_list(&l); + hget_xdimen_node(&x); @+hwrite_xdimen_node(&x); + hget_glue_node();@+ + hget_list(&l);@+ hwrite_list(&l);@+ + hget_glue_node(); + } + @<read and check the end byte |z|@>@; + hwrite_end(); + return true; + } +} + +@ + +When stream definitions are part of the page template, we call them +stream insertion points. +They contain only the stream reference and +are parsed by the usual content parsing functions. + +@<cases to get content@>= +@t\1\kern1em@> +case TAG(stream_kind,b100): {uint8_t n=HGET8;@+ REF_RNG(stream_kind,n); @+hwrite_ref(n); @+ break; @+} +@ + + +\subsection{Stream Content} +Stream\index{stream} nodes occur in the content section where they +must not be inside other nodes except toplevel +paragraph\index{paragraph} nodes. A normal stream node contains in this +order: the stream reference number, the optional stream parameters, +and the stream content. The content is either a vertical box or an +extended vertical box. The stream parameters consists of the +|floating_penalty|, the |split_max_depth|, and the +|split_top_skip|. The parameterlist can be given +explicitly or as a reference. + +In the short format, the info bits |b010| indicate +a normal stream content node with an explicit parameter list +and the info bits |b000| a normal stream with a parameter list reference. + +If the info bit |b001| is set, we have a content node of type top, first, +or last. In this case, the short format has instead of the parameter list +a single byte indicating the type. +These types are currently not yet implemented. + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + +@s stream symbol + +@<symbols@>= +%type <info> stream +@ + +@<parsing rules@>= +stream: empty_param_list list {$$=b010;} + | empty_param_list non_empty_param_list list {$$=b010;} + | param_ref list {$$=b000;}; +content_node: start STREAM stream_ref stream END + @/{@+hput_tags($1,TAG(stream_kind,$4)); @+}; +@ + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} + +@<cases to get content@>= +@t\1\kern1em@> +case TAG(stream_kind,b000): HGET_STREAM(b000); @+ break; +case TAG(stream_kind,b010): HGET_STREAM(b010); @+ break; +@ + +When we read stream numbers, we relax the define before use policy. +We just check, that the stream number is in the correct range. +\goodbreak +@<get macros@>= +#define @[HGET_STREAM(I)@] @/\ + {uint8_t n=HGET8;@+ REF_RNG(stream_kind,n); @+hwrite_ref(n);@+}\ +if ((I)&b010) { list_t l; @+hget_param_list(&l); @+hwrite_param_list(&l); @+} \ +else HGET_REF(param_kind);\ +{ list_t l; @+hget_list(&l);@+ hwrite_list(&l); @+} +@ + + + + +\subsection{Page Template Definitions}\label{page} +A \HINT\ file can define multiple page templates\index{template}. Not only +might an index demand a different page layout than the main body of text, +also the front page or the chapter headings might use their own page templates. +Further, the author of a \HINT\ file might define a two column format as +an alternative to a single column format to be used if the display area +is wide enough. + +To help in selecting the right page template, page template definitions start with +a name and an optional priority\index{priority}; the default priority is 1. +The names might appear in a menu from which the user +can select a page layout that best fits her taste. +Without user interaction, the +system can pick the template with the highest priority. Of course, +a user interface might provide means to alter priorities. Future +versions might include sophisticated feature-vectors that +identify templates that are good for large or small displays, +landscape or portrait mode, etc \dots + +After the priority follows a glue node to specify the topskip glue +and the dimension of the maximum page depth, +an extended dimension to specify the page height and +an extended dimension to specify the page width. + +Then follows the main part of a page template definition: the template. +The template consists of a list of vertical material. +To construct the page, this list will be placed +into a vertical box and the glue will be set. +But of course before doing so, the viewer will +scan the list and replace all stream insertion points +by the appropriate content streams. + +Let's call the vertical box obtained this way ``the page''. +The page will fill the entire display area top to bottom and left to right. +It defines not only the appearance of the main body of text +but also the margins, the header, and the footer. +Because the \.{vsize} and \.{hsize} variables of \TeX\ are used for +the vertical and horizontal dimension of the main body of text---they +do not include the margins---the page will usually be wider than \.{hsize} +and taller than \.{vsize}. The dimensions of the page are part +of the page template. The viewer, knowing the actual dimensions +of the display area, can derive from them the actual values of \.{hsize} +and \.{vsize}. + +Stream definitions are listed after the template. + +The page template with number 0 is always defined and has priority 0. +It will display just the main content stream. It puts a small margin +of $\.{hsize}/8 -4.5\hbox{pt}$ all around it. +Given a letter size page, 8.5 inch wide, this formula yields a margin of 1 inch, +matching \TeX's plain format. The margin will be positive as long as +the page is wider than $1/2$ inch. For narrower pages, there will be no +margin at all. In general, the \HINT\ viewer will never set {\tt hsize} larger +than the width of the page and {\tt vsize} larger than its height. + +%8.5 in should give 1 inch margin 2/17 +%612pt should give 72pt margin +%72pt = 612/8-4.5pt +%This would give a positive margin starting at 36pt or 1/2 inch + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + +@s PAGE symbol +@s page_priority symbol +@s page symbol +@s stream_def_list symbol + +@<symbols@>= +%token PAGE "page" +@ + +@<scanning rules@>= +::@=page@> :< return PAGE; >: +@ + +@<parsing rules@>= +page_priority: { HPUT8(1); } + | UNSIGNED { RNG("page priority",$1,0,255); HPUT8($1); }; + +stream_def_list: | stream_def_list stream_def_node; + +page: string { hput_string($1);} page_priority glue_node dimension {@+HPUT32($5);@+} + xdimen_node xdimen_node + list stream_def_list ; +@ + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} +@<get functions@>= +void hget_page(void) +{ char *n; uint8_t p; xdimen_t x; list_t l; + HGET_STRING(n);@+ hwrite_string(n); + p=HGET8; @+ if (p!=1) hwritef(" %d",p); + hget_glue_node(); + hget_dimen(TAG(dimen_kind,b001)); + hget_xdimen_node(&x); @+hwrite_xdimen_node(&x); /* page height */ + hget_xdimen_node(&x); @+hwrite_xdimen_node(&x); /* page width */ + hget_list(&l);@+ hwrite_list(&l); + while (hget_stream_def()) continue; +} +@ + +\subsection{Page Ranges}\label{range}\index{page range} +Not every template\index{template} is necessarily valid for the entire content +section. A page range specifies a start position $a$ and an end +position $b$ in the content section and the page template is valid if +the start position $p$ of the page is within that range: $a\le p < b$. +If paging backward this definition might cause problems because the +start position of the page is known only after the page has been +build. In this case, the viewer might choose a page template based on +the position at the bottom of the page. If it turns out that this ``bottom template'' +is no longer valid when the page builder has found the start of the +page, the viewer might display the page anyway with the bottom +template, it might just display the page with the new ``top +template'', or rerun the whole page building process using this time +the ``top template''. Neither of these alternatives is guaranteed to +produce a perfect result because changing the page template might +change the amount of material that fits on the page. A good page +template design should take this into account. + +The representation of page ranges differs significantly for the short +format and the long format. The short format will include a list of page +ranges in the definition section which consist of a page template number, +a start position, and an end position. In the long format, the start +and end position of a page +range is marked with a page range node switching the availability of a +page template on and off. Such a page range node must be a top level node. +It is an error, to switch a page template +off that was not switched on, or to switch a page template on that was +already switched on. It is permissible to omit switching off a page +template at the very end of the content section. + +While we parse a long format \HINT\ file, we store page ranges and generate +the short format after reaching the end of the content section. +While we parse a short format \HINT\ file, +we check at the end of each top level node whether we should insert a +page range node into the output. +For the \.{shrink} program, it is best +to store the start and end positions of all page ranges +in an array sorted by the position\footnote*{For a \HINT\ viewer, +a data structure which allows fast retrieval of all +valid page templates for a given position is needed.}. +To check the restrictions on the switching of page templates, we +maintain for every page template an index into the range array +which identifies the position where the template was switched on. +A zero value instead of an index will identify templates that +are currently invalid. When switching a range off again, we +link the two array entries using this index. These links +are useful when producing the range nodes in short format. + +A range node in short format contains the template number, the +start position and the end position. +A zero start position +is not stored, the info bit |b100| indicates a nonzero start position. +An end position equal to |HINT_NO_POS| is not stored, +the info bit |b010| indicates a smaller end position. +The info bit |b001| indicates that positions are stored using 2 byte +otherwise 4 byte are used for the positions. + +@<hint types@>= +typedef +struct {@+uint8_t pg; @+uint32_t pos; @+ bool on; @+int link;@+} range_pos_t; +@ + +@<common variables@>= +range_pos_t *range_pos; +int next_range=1, max_range; +int *page_on; +@ + +@<initialize definitions@>= +ALLOCATE(page_on,max_ref[page_kind]+1,int); +ALLOCATE(range_pos,2*(max_ref[range_kind]+1),range_pos_t); +@ + +@<hint macros@>= +#define @[ALLOCATE(R,S,T)@] @/((R)=@[(T *)calloc((S),sizeof(T)),\ + (((R)==NULL)?QUIT("Out of memory for " #R):0)) +#define @[REALLOCATE(R,S,T)@] @/((R)=@[(T *)realloc((R),(S)*sizeof(T)),\ + (((R)==NULL)?QUIT("Out of memory for " #R):0)) +@ + +\readcode +@s RANGE symbol +@<symbols@>= +%token RANGE "range" +@ + +@<scanning rules@>= +::@=range@> :< return RANGE; >: +@ +@<parsing rules@>= + +content_node: START RANGE REFERENCE ON END @/{ REF(page_kind,$3);hput_range($3,true);} + | START RANGE REFERENCE OFF END @/{ REF(page_kind,$3);hput_range($3,false);}; +@ + + +\writecode +@<write functions@>= +void hwrite_range(void) /* called in |hwrite_end| */ +{ uint32_t p=hpos-hstart; + DBG(DBGRANGE,"Range check at pos 0x%x next at 0x%x\n",p,range_pos[next_range].pos); + while (next_range<max_range && range_pos[next_range].pos <= p) + { hwrite_start(); + hwritef("range *%d ",range_pos[next_range].pg); + if (range_pos[next_range].on) hwritef("on"); else hwritef("off"); + nesting--; @+hwritec('>'); /* avoid a recursive call to |hwrite_end| */ + next_range++; + } +} +@ + +\getcode +@<get functions@>= +void hget_range(info_t info, uint8_t pg) +{ uint32_t from, to; + REF(page_kind,pg); + REF(range_kind,(next_range-1)/2); + if (info&b100) @+ + { @+ if (info&b001) HGET32(from); @+else HGET16(from); @+} + else from=0; + if (info&b010) @+ + { @+if (info&b001) HGET32(to); @+else HGET16(to); @+} + else to=HINT_NO_POS; + range_pos[next_range].pg=pg; + range_pos[next_range].on=true; + range_pos[next_range].pos=from; + DBG(DBGRANGE,"Range *%d from 0x%x\n",pg,from); + DBG(DBGRANGE,"Range *%d to 0x%x\n",pg,to); + next_range++; + if (to!=HINT_NO_POS) @/ + { range_pos[next_range].pg=pg; + range_pos[next_range].on=false; + range_pos[next_range].pos=to; + next_range++; + } +} +@ + +@<write functions@>= +void hsort_ranges(void) /* simple insert sort by position */ +{ int i; + DBG(DBGRANGE,"Range sorting %d positions\n",next_range-1); + for(i=3; i<next_range; i++)@/ + { int j = i-1; + if (range_pos[i].pos < range_pos[j].pos) @/ + { range_pos_t t; + t= range_pos[i]; + do { + range_pos[j+1] = range_pos[j]; + j--; + } while (range_pos[i].pos < range_pos[j].pos); + range_pos[j+1] = t; + } + } + max_range=next_range; @+next_range=1; /* prepare for |hwrite_range| */ +} +@ + +\putcode +@<put functions@>= +void hput_range(uint8_t pg, bool on) +{ if (((next_range-1)/2)>max_ref[range_kind]) + QUIT("Page range %d > %d",(next_range-1)/2,max_ref[range_kind]); + if (on && page_on[pg]!=0) + QUIT(@["Template %d is switched on at 0x%x and " SIZE_F@],@| + pg, range_pos[page_on[pg]].pos, hpos-hstart); + else if (!on && page_on[pg]==0) + QUIT(@["Template %d is switched off at " SIZE_F " but was not on"@],@| + pg, hpos-hstart); + DBG(DBGRANGE,@["Range *%d %s at " SIZE_F "\n"@],pg,on?"on":"off",hpos-hstart); + range_pos[next_range].pg=pg; + range_pos[next_range].pos=hpos-hstart; + range_pos[next_range].on=on; + if (on) page_on[pg]=next_range; + else @/{ range_pos[next_range].link =page_on[pg]; + range_pos[page_on[pg]].link=next_range; + page_on[pg]=0; } + next_range++; +} + +void hput_range_defs(void) +{ int i; + section_no=1; + hstart=dir[1].buffer; + hend=hstart+ dir[1].bsize; + hpos=hstart+dir[1].size; + for (i=1; i< next_range;i++) + if (range_pos[i].on)@/ + { info_t info=b000; + uint32_t p=hpos++-hstart; + uint32_t from, to; + HPUT8(range_pos[i].pg); + from= range_pos[i].pos; + if (range_pos[i].link!=0) to = range_pos[range_pos[i].link].pos; + else to=HINT_NO_POS; + if (from!=0) @/ + { info=info|b100;@+ if (from>0xFFFF) @+ info=info|b001;@+} + if (to!=HINT_NO_POS) @/ + { info=info|b010;@+ if (to>0xFFFF) info=info|b001;@+ } + if (info & b100) @/ + { @+if (info & b001) HPUT32(from); @+else HPUT16(from); @+} + if (info & b010) @/ + { @+if (info & b001) HPUT32(to); @+else HPUT16(to); @+} + DBG(DBGRANGE,"Range *%d from 0x%x to 0x%x\n",@|range_pos[i].pg,from, to); + hput_tags(p,TAG(range_kind,info)); + } + hput_definitions_end(); + } +@ + + +\section{File Structure}\hascode +All \HINT\ files\index{file} start with a banner\index{banner} as +described below. After that, they contain three mandatory +sections\index{section}: the directory\index{directory section} +section, the definition\index{definition section} section, and the +content\index{content section} section. Usually, further +optional\index{optional section} sections follow. In short format +files, these contain auxiliary\index{auxiliary file} files +(fonts\index{font}, images\index{image}, \dots) necessary for +rendering the content. In long format files, the directory section +will simply list the file names of the auxiliary files. + + + +\subsection{Banner} +All \HINT\ files start with a banner\index{banner}. The banner contains only +printable ASCII characters and spaces; +its end is marked with a newline character\index{newline character}. +The first four byte are the ``magic'' number by which you recognize a \HINT\ +file. It consists of the four ASCII codes `{\tt H}', `{\tt I}', `{\tt N}', +and `{\tt T}' in the long format and `{\tt h}', `{\tt i}', `{\tt n}', +and `{\tt t}' in the short format. Then follows a space, then +the version number, a dot, the sub-version number, and another +space. Both numbers are encoded as decimal ASCII strings. The +remainder of the banner is simply ignored but may be used to contain +other useful information about the file. The maximum size of the +banner is 256 byte. +@<hint macros@>= +#define HINT_VERSION 1 +#define HINT_SUB_VERSION 3 +#define MAX_BANNER 256 +@ + +\goodbreak +To check the banner, we have the function |hcheck_banner|; +it returns |true| if successful. + +@<common variables@>= +char hbanner[MAX_BANNER+1]; +@ + +@<function to check the banner@>= + +bool hcheck_banner(char *magic) +{ int hbanner_size=0; + int v; + char *t; + t=hbanner; + if (strncmp(magic,hbanner,4)!=0) + { MESSAGE("This is not a %s file",magic); return false; } + else t+=4; + hbanner_size=(int)strnlen(hbanner,MAX_BANNER); + if(hbanner[hbanner_size-1]!='\n') + { MESSAGE("Banner exceeds maximum size=0x%x",MAX_BANNER); return false; } + if (*t!=' ') + { MESSAGE("Space expected in banner after %s",magic); return false; } + else t++; + v=strtol(t,&t,10); + if (v!=HINT_VERSION) + { MESSAGE("Wrong HINT version: got %d, expected %d",v,HINT_VERSION); return false; } + if (*t!='.') + { MESSAGE("Dot expected in banner after HINT version number"); return false; } + else t++; + v=strtol(t,&t,10); + if (v!=HINT_SUB_VERSION) + { MESSAGE("Wrong HINT subversion: got %d, expected %d",v,HINT_SUB_VERSION); return false; } + if (*t!=' ' && *t!='\n') + { MESSAGE("Space expected in banner after HINT subversion"); return false; } + LOG("%s file version %d.%d:%s",magic,HINT_VERSION, HINT_SUB_VERSION, t); + DBG(DBGDIR,"banner size=0x%x\n",hbanner_size); + return true; +} +@ + +To read a short format file, we use the macro |HGET8|. It returns a single byte. +We read the banner knowing that it ends with a newline character +and is at most |MAX_BANNER| byte long. Because this is the first access to a yet unknown file, +we are very careful and make sure we do not read past the end of the file. +Checking the banner is a separate step. + +\getcode +@<get file functions@>= +void hget_banner(void) +{ int i; + for (i=0;i<MAX_BANNER && hpos<hend;i++)@/ + { hbanner[i]=HGET8; + if (hbanner[i]=='\n') break; + } + hbanner[++i]=0; +} +@ + +To read a long format file, we use the function |fgetc|. +\readcode +@<read the banner@>= +{ int i,c; + for (i=0;i<MAX_BANNER && (c=fgetc(hin))!=EOF;i++)@/ + { hbanner[i]=c; + if (hbanner[i]=='\n') break; + } + hbanner[++i]=0; +} +@ + +Writing the banner to a short format file is accomplished by calling +|hput_banner| with the ``magic'' string |"hint"| as a first argument +and a (short) comment as the second argument. +\putcode +@<function to write the banner@>= + +static size_t hput_banner(char *magic, char *s) +{ return fprintf(hout,"%s %d.%d %s\n",magic,HINT_VERSION,HINT_SUB_VERSION,s); +} +@ + + +\writecode +Writing the banner of a long format file is essentially the same as for a short +format file calling |hput_banner| with |"HINT"| as a first argument. + +\subsection{Long Format Files}\gdef\subcodetitle{Banner}% + +After reading and checking the banner, reading a long format file is +simply done by calling |yyparse|. The following rule gives the big picture: +\readcode +@s hint symbol +@s content_section symbol + +@<parsing rules@>= +hint: directory_section definition_section content_section ; +@ + + +\subsection{Short Format Files}\gdef\subcodetitle{Primitives}% +A short format\index{short format} file starts with the banner and continues +with a list of sections. Each section has a maximum size +of $2^{32}$ byte or 4GByte. This restriction ensures that positions\index{position} +inside a section can be stored as 32 bit integers, a feature that +we will need only for the so called ``content'' section, but it +is also nice for implementers to know in advance what sizes to expect. +The big picture is captured by the |put_hint| function: + +@<put functions@>= +static size_t hput_root(void); +static size_t hput_section(uint16_t n); +static void hput_optional_sections(void); + +void hput_hint(char * str) +{ size_t s; + DBG(DBGBASIC,"Writing hint output %s\n",str); + s=hput_banner("hint",str); + DBG(DBGDIR,@["Root entry at " SIZE_F "\n"@],s); + s+=hput_root(); + DBG(DBGDIR,@["Directory section at " SIZE_F "\n"@],s); + s+=hput_section(0); + DBG(DBGDIR,@["Definition section at " SIZE_F "\n"@],s); + s+=hput_section(1); + DBG(DBGDIR,@["Content section at " SIZE_F "\n"@],s); + s+=hput_section(2); + DBG(DBGDIR,@["Auxiliary sections at " SIZE_F "\n"@],s); + hput_optional_sections(); +} +@ + + +When we work on a section, we will have the entire section in +memory and use three variables to access it: |hstart| +points to the first byte of the section, |hend| points +to the byte after the last byte of the section, and |hpos| points to the +current position inside the section.\label{hpos} +The auxiliary variable |hpos0| contains the |hpos| value of the +last content node on nesting level zero. + +@<common variables@>= +uint8_t *hpos=NULL, *hstart=NULL, *hend=NULL, *hpos0=NULL; +@ + +There are two sets of macros that read or write binary data at the current position +and advance the stream position accordingly.\label{HPUT}\label{HGET} + +\getcode +@<shared get macros@>= +#define HGET_ERROR @/ QUIT(@["HGET overrun in section %d at " SIZE_F "\n"@],@|section_no,hpos-hstart) +#define @[HEND@] @[((hpos<=hend)?0:(HGET_ERROR,0))@] + +#define @[HGET8@] ((hpos<hend)?*(hpos++):(HGET_ERROR,0)) +#define @[HGET16(X)@] ((X)=(hpos[0]<<8)+hpos[1],hpos+=2,HEND) +#define @[HGET24(X)@] ((X)=(hpos[0]<<16)+(hpos[1]<<8)+hpos[2],hpos+=3,HEND) +#define @[HGET32(X)@] ((X)=(hpos[0]<<24)+(hpos[1]<<16)+(hpos[2]<<8)+hpos[3],hpos+=4,HEND) +#define @[HGETTAG(A)@] @[A=HGET8,DBGTAG(A,hpos-1)@] +@ + +\putcode +@<put functions@>= +void hput_error(void) +{@+if (hpos<hend) return; + QUIT(@["HPUT overrun section %d pos=" SIZE_F "\n"@],@|section_no,hpos-hstart); +} +@ + +@<put macros@>= +extern void hput_error(void); +#define @[HPUT8(X)@] (hput_error(),*(hpos++)=(X)) +#define @[HPUT16(X)@] (HPUT8(((X)>>8)&0xFF),HPUT8((X)&0xFF)) +#define @[HPUT24(X)@] (HPUT8(((X)>>16)&0xFF),HPUT8(((X)>>8)&0xFF),HPUT8((X)&0xFF)) +#define @[HPUT32(X)@] (HPUT8(((X)>>24)&0xFF),HPUT8(((X)>>16)&0xFF),HPUT8(((X)>>8)&0xFF),HPUT8((X)&0xFF)) +@ + +The above macros test for buffer overruns\index{buffer overrun}; +allocating sufficient buffer space is done separately. + +Before writing a node, we will insert a test and increase the buffer if necessary. +@<put macros@>= +void hput_increase_buffer(uint32_t n); +#define @[HPUTX(N)@] @[(((hend-hpos) < (N))? hput_increase_buffer(N):(void)0)@] +#define HPUTNODE @[HPUTX(MAX_TAG_DISTANCE)@] +#define @[HPUTTAG(K,I)@] @|@[(HPUTNODE,@+DBGTAG(TAG(K,I),hpos),@+HPUT8(TAG(K,I)))@] +@ + +Fortunately the only data types that have an unbounded size are +strings\index{string} and texts\index{text}. +For these we insert specific tests. For all other cases a relatively +small upper bound on the maximum distance between two tags can be determined. +Currently the maximum distance between tags is 26 byte as can be determined +from the |hnode_size| array described in appendix~\secref{fastforward}. +The definition below uses a slightly larger value leaving some room +for future changes in the design of the short file format. + +@<hint macros@>= +#define MAX_TAG_DISTANCE 32 +@ + +\subsection{Mapping a Short Format File to Memory} +In the following, we implement two alternatives to map a file into memory. +The first implementation, opens the file, gets its size, allocates memory, +and reads the file. The second implementation uses a call to |mmap|. + +Since modern computers with 64bit hardware have a huge address space, +using |mmap| to map the entire file into virtual memory is the most efficient way +to access a large file. ``Mapping'' is not the same as ``reading'' and it is +not the same as allocating precious memory, all that is done by the +operating system when needed. Mapping just reserves addresses. +There is one disadvantage of mapping: it typically locks the underlying file +and will not allow a separate process to modify it. This prevents using +this method for previewing a \HINT\ file while editing and recompiling it. +In this case, the first implementation, which has a copy of the file in memory, +is the better choice. To select the second implementation, define the macro |USE_MMAP|. + +The following functions map and unmap a short format input +file setting |hin_addr| to its address and |hin_size| to its size. +The value |hin_addr==NULL| indicates, that no file is open. +The variable |hin_time| is set to the time when the file was last modified. +It can be used to detect modifications of the file and reload it.\label{map} + +@<common variables@>= +char *hin_name=NULL; +uint64_t hin_size=0; +uint8_t *hin_addr=NULL; +uint64_t hin_time=0; +@ + +@<map functions@>= +#ifndef USE_MMAP +void hget_unmap(void) +{@+ if (hin_addr!=NULL) free(hin_addr); + hin_addr=NULL; + hin_size=0; +} +bool hget_map(void) +{ FILE *f; + struct stat st; + size_t s,t,u; + f= fopen(hin_name,"rb"); + if (f==NULL)@/ + { MESSAGE("Unable to open file: %s", hin_name);@+ return false;@+ } + if (stat(hin_name,&st)<0) + { MESSAGE("Unable to obtain file size: %s", hin_name); + fclose(f); + return false; + } + if (st.st_size==0) + { MESSAGE("File %s is empty", hin_name); + fclose(f); + return false; + } + if (hin_addr!=NULL) hget_unmap(); + hin_addr=malloc(st.st_size); + if (hin_addr==NULL) + { MESSAGE("Unable to allocate %ld byte for File %s", st.st_size,hin_name); + fclose(f); + return 0; + } + t=0;@+ + u=st.st_size; + do{ + s=fread(hin_addr+t,1,u,f); + if (s<=0) + { MESSAGE("Unable to read file %s",hin_name); + fclose(f); + free(hin_addr); + hin_addr=NULL; + return false; + } + t=t+s;@+ + u=u-s; + } while (u>0); + hin_size=st.st_size; + hin_time=st.st_mtime; + return true; +} + +#else + +#include <sys/mman.h> + +void hget_unmap(void) +{@+ munmap(hin_addr,hin_size); + hin_addr=NULL; + hin_size=0; +} + +bool hget_map(void) +{ struct stat st; + int fd; + fd = open(hin_name, O_RDONLY, 0); + if (fd<0)@/ + { MESSAGE("Unable to open file %s", hin_name);@+ return false;@+ } + if (fstat(fd, &st)<0) + { MESSAGE("Unable to get file size"); + close(fd); + return false; + } + if (st.st_size==0) + { MESSAGE("File %s is empty",hin_name); + close(fd); + return false; + } + if (hin_addr!=NULL) hget_unmap(); + hin_size=st.st_size; + hin_time=st.st_mtime; + hin_addr= mmap(NULL,hin_size,PROT_READ,MAP_PRIVATE,fd, 0); + if (hin_addr==MAP_FAILED) + { close(fd); + hin_addr=NULL;hin_size=0; + MESSAGE("Unable to map file into memory"); + return 0; + } + close(fd); + return hin_size; +} +#endif + +@ +\subsection{Compression} +The short file format offers the possibility to store sections in +compressed\index{compression} form. We use the {\tt zlib}\index{zlib+{\tt zlib}} compression library\cite{zlib}\cite{RFC1950} +to deflate\index{deflate} and inflate\index{inflate} individual sections. When one of the following +functions is called, we can get the section buffer, the buffer size +and the size actually used from the directory entry. If a section +needs to be inflated, its size after decompression is found in the +|xsize| field; if a section needs to be deflated, its size after +compression will be known after deflating it. + +@s z_stream int + +@<get file functions@>= + +static void hdecompress(uint16_t n) +{ z_stream z; /* decompression stream */ + uint8_t *buffer; + int i; + + DBG(DBGCOMPRESS,"Decompressing section %d from 0x%x to 0x%x byte\n",@|n, dir[n].size, dir[n].xsize); + z.zalloc = (alloc_func)0;@+ + z.zfree = (free_func)0;@+ + z.opaque = (voidpf)0; + z.next_in = hstart; + z.avail_in = hend-hstart; + if (inflateInit(&z)!=Z_OK) + QUIT("Unable to initialize decompression: %s",z.msg); + ALLOCATE(buffer,dir[n].xsize+MAX_TAG_DISTANCE,uint8_t); + DBG(DBGBUFFER,"Allocating output buffer size=0x%x, margin=0x%x\n",dir[n].xsize,MAX_TAG_DISTANCE); + z.next_out = buffer; + z.avail_out =dir[n].xsize+MAX_TAG_DISTANCE; + i= inflate(&z, Z_FINISH); + DBG(DBGCOMPRESS,"in: avail/total=0x%x/0x%lx "@|"out: avail/total=0x%x/0x%lx, return %d;\n",@| + z.avail_in,z.total_in, z.avail_out, z.total_out,i); + if (i!=Z_STREAM_END) + QUIT("Unable to complete decompression: %s",z.msg); + if (z.avail_in != 0) + QUIT("Decompression missed input data"); + if (z.total_out != dir[n].xsize) + QUIT("Decompression output size mismatch 0x%lx != 0x%x",z.total_out, dir[n].xsize ); + if (inflateEnd(&z)!=Z_OK) + QUIT("Unable to finalize decompression: %s",z.msg); + dir[n].buffer=buffer; + dir[n].bsize=dir[n].xsize; + hpos0=hpos=hstart=buffer; + hend=hstart+dir[n].xsize; +} +@ + + +@<put functions@>= +static void hcompress(uint16_t n) +{ z_stream z; /* compression stream */ + uint8_t *buffer; + int i; + if (dir[n].size==0) { dir[n].xsize=0;@+ return; @+} + DBG(DBGCOMPRESS,"Compressing section %d of size 0x%x\n",n, dir[n].size); + z.zalloc = (alloc_func)0;@+ + z.zfree = (free_func)0;@+ + z.opaque = (voidpf)0; + if (deflateInit(&z,Z_DEFAULT_COMPRESSION)!=Z_OK) + QUIT("Unable to initialize compression: %s",z.msg); + ALLOCATE(buffer,dir[n].size+MAX_TAG_DISTANCE,uint8_t); + z.next_out = buffer; + z.avail_out = dir[n].size+MAX_TAG_DISTANCE; + z.next_in = dir[n].buffer; + z.avail_in = dir[n].size; + i=deflate(&z, Z_FINISH); + DBG(DBGCOMPRESS,"deflate in: avail/total=0x%x/0x%lx out: avail/total=0x%x/0x%lx, return %d;\n",@| + z.avail_in,z.total_in, z.avail_out, z.total_out,i); + if (z.avail_in != 0) + QUIT("Compression missed input data"); + if (i!=Z_STREAM_END) + QUIT("Compression incomplete: %s",z.msg); + if (deflateEnd(&z)!=Z_OK) + QUIT("Unable to finalize compression: %s",z.msg); + DBG(DBGCOMPRESS,"Compressed 0x%lx byte to 0x%lx byte\n",@|z.total_in,z.total_out); + free(dir[n].buffer); + dir[n].buffer=buffer; + dir[n].bsize=dir[n].size+MAX_TAG_DISTANCE; + dir[n].xsize=dir[n].size; + dir[n].size=z.total_out; +} +@ + + + +\subsection{Reading Short Format Sections} +\gdef\subcodetitle{Sections}% + +After mapping the file at address |hin_addr| access to sections of the +file is provided by decompressing them if necessary and +setting the three pointers |hpos|, |hstart|, and +|hend|. + +To read sections of a short format input file, we use the function |hget_section|. + +\getcode +%\codesection{\getsymbol}\getindex{1}{3}{Files} + +@<get file functions@>= +void hget_section(uint16_t n) +{ DBG(DBGDIR,"Reading section %d\n",n); + RNG("Section number",n,0,max_section_no); + if (dir[n].buffer!=NULL && dir[n].xsize>0) + { hpos0=hpos=hstart=dir[n].buffer; + hend=hstart+dir[n].xsize; + } + else + { hpos0=hpos=hstart=hin_addr+dir[n].pos; + hend=hstart+dir[n].size; + if (dir[n].xsize>0) hdecompress(n); + } +} +@ +\subsection{Writing Short Format Sections} +\gdef\subcodetitle{Sections}% + +To write a short format file, we allocate for each of the first three sections a +suitable buffer\index{buffer}, then fill these buffers, and finally write them +out in sequential order. + +@<put functions@>= +#define BUFFER_SIZE 0x400 +void new_output_buffers(void) +{ dir[0].bsize=dir[1].bsize=dir[2].bsize=BUFFER_SIZE; + DBG(DBGBUFFER,"Allocating output buffer size=0x%x, margin=0x%x\n",BUFFER_SIZE,MAX_TAG_DISTANCE); + ALLOCATE(dir[0].buffer,dir[0].bsize+MAX_TAG_DISTANCE,uint8_t); + ALLOCATE(dir[1].buffer,dir[1].bsize+MAX_TAG_DISTANCE,uint8_t); + ALLOCATE(dir[2].buffer,dir[2].bsize+MAX_TAG_DISTANCE,uint8_t); +} + +void hput_increase_buffer(uint32_t n) +{ size_t bsize; + uint32_t pos, pos0; + const double buffer_factor=1.4142136; /* $\sqrt 2$ */ + pos=hpos-hstart; pos0=hpos0-hstart; + bsize=dir[section_no].bsize*buffer_factor+0.5; + if (bsize<pos+n) bsize=pos+n; + if (bsize>=HINT_NO_POS) bsize=HINT_NO_POS; + if (bsize<pos+n) QUIT(@["Unable to increase buffer size " SIZE_F " by 0x%x byte"@],@|hpos-hstart,n); + DBG(DBGBUFFER,@["Reallocating output buffer "@|" for section %d from 0x%x to " SIZE_F " byte\n"@], + section_no,dir[section_no].bsize,bsize); + REALLOCATE(dir[section_no].buffer,bsize,uint8_t); + dir[section_no].bsize=(uint32_t)bsize; + hstart=dir[section_no].buffer; + hend=hstart+bsize; + hpos0=hstart+pos0; hpos=hstart+pos; +} + +static size_t hput_data(uint16_t n, uint8_t *buffer, uint32_t size) +{ size_t s; + s=fwrite(buffer,1,size,hout); + if (s!=size) + QUIT(@["short write " SIZE_F " < %d in section %d"@],s,size,n); + return s; +} + +static size_t hput_section(uint16_t n) +{ return hput_data(n, dir[n].buffer,dir[n].size); +} +@ + + + + +\section{Directory Section} +A \HINT\ file is subdivided in sections and +each section can be identified by its section number. +The first three sections, numbered 0, 1, and 2, are mandatory: +directory\index{directory section} section, definition section, and content section. +The directory section, which we explain now, lists all sections +that make up a \HINT\ file. + +A document will often contain not only plain text but also other media +for example illustrations. Illustrations are produced with specialized +tools and stored in specialized files. Because a \HINT\ file in short format +should be self contained, these special files are embedded in the \HINT\ file +as optional sections. +Because a \HINT\ file in long format should be readable, these special files +are written to disk and only the file names are retained in the directory. +Writing special files to disk has also the advantage that you can modify +them individually before embedding them in a short format file. + + +\subsection{Directories in Long Format}\gdef\subcodetitle{Directory Section}% +The directory\index{directory section} section of a long format \HINT\ file starts +with the ``\.{directory}'' keyword; then follows the maximum section number used and +a list of directory entries, one for each optional section numbered 3 and above. +Each entry consists of the keyword ``\.{section}'' followed by the +section number, followed by the file name. +The section numbers must be unique and fit into 16 bit. +The directory entries must be ordered with strictly increasing section numbers. +Keeping section numbers consecutive is recommended because it reduces the +memory footprint if directories are stored as arrays indexed by the section +number as we will do below. + +\readcode +@s directory_section symbol +@s entry_list symbol +@s entry symbol +@s DIRECTORY symbol +@s SECTION symbol + +@<symbols@>= +%token DIRECTORY "directory" +%token SECTION "entry" +@ + +@<scanning rules@>= +::@=directory@> :< return DIRECTORY; >: +::@=section@> :< return SECTION; >: +@ + +@<parsing rules@>= +directory_section: START DIRECTORY UNSIGNED @|{new_directory($3+1); new_output_buffers();} entry_list END ; +entry_list: @,@+ | entry_list entry; +entry: START SECTION UNSIGNED string END @/ + { RNG("Section number",$3,3,max_section_no); hset_entry(&(dir[$3]), $3,0,0,$4);}; +@ + + + +We use a dynamically allocated array +of directory entries to store the directory. + +@<directory entry type@>= +typedef struct { +uint64_t pos; +uint32_t size, xsize; +uint16_t section_no; +char *file_name; +uint8_t *buffer; +uint32_t bsize; +} entry_t; +@ + + +The function |new_directory| allocates the directory. + +@<directory functions@>= +entry_t *dir=NULL; +uint16_t section_no, max_section_no; +void new_directory(uint32_t entries) +{ DBG(DBGDIR,"Creating directory with %d entries\n", entries); + RNG("Directory entries",entries,3,0x10000); + max_section_no=entries-1;@+ + ALLOCATE(dir,entries,entry_t); + dir[0].section_no=0; @+ dir[1].section_no=1; @+ dir[2].section_no=2; +} +@ + +The function |hset_entry| fills in the appropriate entry. +@<directory functions@>= +void hset_entry(entry_t *e, uint16_t i, uint32_t size, uint32_t xsize, @|char *file_name) +{ e->section_no=i; + e->size=size; @+e->xsize=xsize; + if (file_name==NULL || *file_name==0) + e->file_name=NULL; + else + e->file_name=strdup(file_name); + DBG(DBGDIR,"Creating entry %d: \"%s\" size=0x%x xsize=0x%x\n",@|i,file_name,size,xsize); +} +@ + + +Writing the auxiliary files depends on the {\tt -f} and the {\tt -g} +option. + +@<without {\tt -f} skip writing an existing file@>= + if ( !option_force && access(file_name,F_OK)==0) + { MESSAGE("File '%s' exists.\n"@| "To rewrite the file use the -f option.\n", + file_name); + continue; + } +@ + +The above code uses the |access| function, and we need to make sure it is defined: +@<make sure |access| is defined@>= +#ifdef WIN32 +#include <io.h> +#define @[access(N,M)@] @[_access(N, M )@] +#define F_OK 0 +#else +#include <unistd.h> +#endif +@ + +With the {\tt -g} option, filenames are considered global, and files +are written to the filesystem possibly overwriting the existing files. +For example a font embedded in a \HINT\ file might replace a font of +the same name in some operating systems font folder. +If the \HINT\ file is {\tt shrink}ed on one system and +{\tt stretch}ed on another system, this is usually not the desired behavior. +Without the {\tt -g} option,\label{absrel} the files will be written in two local directories. +The names of these directories are derived from the output file name, +replacing the extension ``{\tt .HINT}'' with ``{\tt .abs}'' if the original +filename contained an absolute path, and replacing it with ``{\tt .rel}'' +if the original filename contained a relative path. Inside these directories, +the path as given in the filename is retained. +When {\tt shrink}ing a \HINT\ file without the {\tt -g} option, +the original filenames can be reconstructed. + +@<without {\tt -g} compute a local |file_name|@>= +if (!option_global) +{ int path_length=(int)strlen(file_name); + @<determine whether |file_name| is absolute or relative@>@; + if (file_name_length<stem_length+ext_length+path_length) + { file_name_length=stem_length+ext_length+path_length; + REALLOCATE(stem_name, file_name_length+1,char); + } + strcpy(stem_name+stem_length,aux_ext[name_type]); + strcpy(stem_name+stem_length+ext_length,file_name); + DBG(DBGDIR,"Replacing auxiliary file name:\n\t%s\n->\t%s\n",file_name,stem_name); + file_name=stem_name; +} +@ + +@<determine whether |file_name| is absolute or relative@>= + enum {absolute=0, relative=1} name_type; + char *aux_ext[2]={".abs/",".rel/"}; + int ext_length=5; + if (file_name[0]=='/') + { name_type=absolute; + file_name++; path_length--; + } + else if (path_length>3 && isalpha(file_name[0]) && + file_name[1]==':' && file_name[2]=='/') + { name_type=absolute; + file_name[1]='_'; + } + else + name_type=relative; +@ +It remains to create the directories along the path we might have constructed. +@<make sure the path in |file_name| exists@>= +{ char *path_end; + path_end=file_name+1; + while (*path_end!=0) + { if(*path_end=='/') + { struct stat s; + *path_end=0; + if (stat(file_name,&s)==-1) + { +#ifdef WIN32 + if (mkdir(file_name)!=0) +#else + @t\2\kern-1em@>if (mkdir(file_name,0777)!=0) +#endif + QUIT("Unable to create directory %s",file_name); + DBG(DBGDIR,"Creating directory %s\n",file_name); + } else if (!(S_IFDIR&s.st_mode)) + QUIT("Unable to create directory %s, file exists",file_name); + *path_end='/'; + } + path_end++; + } +} + + +@ + +\writecode +@<write functions@>= +@<make sure |access| is defined@>@; +extern char *stem_name; +extern int stem_length; + +void hget_section(uint16_t n); +void hwrite_aux_files(void) +{ int i; + DBG(DBGBASIC|DBGDIR,"Writing %d aux files\n",max_section_no-2); + for (i=3;i<=max_section_no;i++) + { FILE *f; + char * file_name=dir[i].file_name; + int file_name_length=0; + + + @<without {\tt -g} compute a local |file_name|@>@; + @<without {\tt -f} skip writing an existing file@>@; + @<make sure the path in |file_name| exists@>@; + + f=fopen(file_name,"wb"); + if (f==NULL) + QUIT("Unable to open file '%s' for writing",file_name); + else + { size_t s; + hget_section(i); + DBG(DBGDIR,"Writing file %s\n",file_name); + s=fwrite(hstart,1,dir[i].size,f); + if (s!=dir[i].size) QUIT("writing file %s",file_name); + fclose(f); + } + } +} +@ + +We write the directory, and the directory entries +in long format using the following functions. +@<write functions@>= +static void hwrite_entry(int i) +{ hwrite_start(); + hwritef("section %u",dir[i].section_no);@+ hwrite_string(dir[i].file_name); + hwrite_end(); +} + +void hwrite_directory(void) +{ int i; + if (dir==NULL) QUIT("Directory not allocated"); + section_no=0; + hwritef("<directory %u", max_section_no);@/ + for (i=3;i<=max_section_no;i++) + hwrite_entry(i); + hwritef("\n>\n"); +} +@ + +\subsection{Directories in Short Format} +The directory\index{directory section} section of a short format file contains entries +for all sections including the directory section itself. After reading the +directory section, enough information---position and size---is available to +access any section directly. As usual, a directory entry starts and ends with +a tag byte. The kind part of an entry's tag is not used; it is always zero. +The value $s$ of the two least significant bits of the info part indicate +that sizes are stored using $s+1$ byte. The most significant bit of the info +part is 1 if the section is stored in compressed\index{compression} form. In this case the size +of the section is followed by the size of the section after decompressing it. +After the tag byte follows the section number. In the short format file, +section numbers must be strictly increasing and consecutive. This is redundant but helps +with checking. Then follows the size---or the sizes---of the section. After the size +follows the file name terminated by a zero byte. The file name might be an empty +string in which case there is just the zero byte. After the zero byte follows +a copy of the tag byte. + +Here is the macro and function to read a directory\index{directory entry} entry: +\gdef\subcodetitle{Directory Entries}% +\getcode + +@<shared get macros@>= +#define @[HGET_SIZE(I)@] \ + if ((I)&b100) { \ + if (((I)&b011)==0) s=HGET8,xs=HGET8; \ + else if (((I)&b011)==1) HGET16(s),HGET16(xs); \ + else if (((I)&b011)==2) HGET24(s),HGET24(xs); \ + else if (((I)&b011)==3) HGET32(s),HGET32(xs); \ + } \ + else { \ + if (((I)&b011)==0) s=HGET8; \ + else if (((I)&b011)==1) HGET16(s); \ + else if (((I)&b011)==2) HGET24(s); \ + else if (((I)&b011)==3) HGET32(s); \ + } + +#define @[HGET_ENTRY(I,E)@] \ +{ uint16_t i; \ + uint32_t s=0,xs=0; \ + char *file_name; \ + HGET16(i); @+HGET_SIZE(I); @+HGET_STRING(file_name); @/\ + hset_entry(&(E),i,s,xs,file_name); \ +} +@ + +@<get file functions@>= +void hget_entry(entry_t *e) +{ @<read the start byte |a|@>@; + DBG(DBGDIR,"Reading directory entry\n"); + switch(a) + { case TAG(0,b000+0): HGET_ENTRY(b000+0,*e);@+ break; + case TAG(0,b000+1): HGET_ENTRY(b000+1,*e);@+ break; + case TAG(0,b000+2): HGET_ENTRY(b000+2,*e);@+ break; + case TAG(0,b000+3): HGET_ENTRY(b000+3,*e);@+ break; + case TAG(0,b100+0): HGET_ENTRY(b100+0,*e);@+ break; + case TAG(0,b100+1): HGET_ENTRY(b100+1,*e);@+ break; + case TAG(0,b100+2): HGET_ENTRY(b100+2,*e);@+ break; + case TAG(0,b100+3): HGET_ENTRY(b100+3,*e);@+ break; + default: TAGERR(a); @+ break; + } + @<read and check the end byte |z|@>@; +} +@ + +Because the first entry in the directory section describes the +directory section itself, we can not check its info bits in advance to determine +whether it is compressed or not. Therefore the directory section +starts with a root entry, which is always uncompressed. It describes +the remainder of the directory which follows. +There are two differences between the root entry and a normal entry: +it starts with the maximum section number instead of the section number zero, +and we set its position to the position of the +entry for section 1 (which might already be compressed). +The name of the directory section must be the empty string. +\gdef\subcodetitle{Directory Section}% +\getcode +@<get file functions@>= +static void hget_root(entry_t *root) +{ DBG(DBGDIR,"Root entry at " SIZE_F "\n",hpos-hstart); + hget_entry(root); + root->pos=hpos-hstart; + max_section_no=root->section_no; + root->section_no=0; + if (max_section_no<2) QUIT("Sections 0, 1, and 2 are mandatory"); +} + +void hget_directory(void) +{ int i; + entry_t root={0}; + hget_root(&root); + DBG(DBGDIR,"Directory\n"); + new_directory(max_section_no+1); + dir[0]=root; + DBG(DBGDIR,"Directory entry 1 at 0x%"PRIx64"\n",dir[0].pos); + hget_section(0); + for (i=1;i<=max_section_no;i++)@/ + { hget_entry(&(dir[i]));@+ + dir[i].pos=dir[i-1].pos +dir[i-1].size;@+ + DBG(DBGDIR,"Section %d at 0x%"PRIx64"\n",i,dir[i].pos); + } +} + +void hclear_dir(void) +{ int i; + if (dir==NULL) return; + for (i=0;i<3;i++) /* currently the only compressed sections */ + if (dir[i].xsize>0 && dir[i].buffer!=NULL) free(dir[i].buffer); + free(dir); dir=NULL; +} + +@ + +When the \.{shrink} program writes the directory section in the short format, +it needs to know the sizes of all the sections---including the optional sections. +These sizes are not provided in the long format because it is safer and more +convenient to let the machine figure out the file sizes\index{file size}. + +@<set the file sizes for optional sections@>= +{ int i; + for (i=3;i<=max_section_no;i++) + { struct stat s; + char *file_name=dir[i].file_name; + int file_name_length=0; + @<without {\tt -g} compute a local |file_name|@>@; + if (stat(file_name,&s)!=0) + QUIT("Unable to obtain file size for '%s'",dir[i].file_name); + dir[i].size=s.st_size; + dir[i].xsize=0; + } +} +@ + +The computation of the sizes of the mandatory sections will be +explained later. +Armed with these preparations, we can put the directory into the \HINT\ file. + +\gdef\subcodetitle{Directory Section}% +\putcode +@<put functions@>= +static void hput_entry(entry_t *e) +{ uint8_t b; + if (e->size<0x100 && e->xsize<0x100) b=0; + else if (e->size<0x10000 &&e->xsize<0x10000) b=1; + else if (e->size<0x1000000 &&e->xsize<0x1000000) b=2; + else b=3; + if (e->xsize!=0) b =b|b100; + DBG(DBGTAGS,"Directory entry no=%d size=0x%x xsize=0x%x\n",e->section_no, e->size, e->xsize); + HPUTTAG(0,b);@/ + HPUT16(e->section_no); + switch (b) { + case 0: HPUT8(e->size);@+break; + case 1: HPUT16(e->size);@+break; + case 2: HPUT24(e->size);@+break; + case 3: HPUT32(e->size);@+break; + case b100|0: HPUT8(e->size);@+HPUT8(e->xsize);@+break; + case b100|1: HPUT16(e->size);@+HPUT16(e->xsize);@+break; + case b100|2: HPUT24(e->size);@+HPUT24(e->xsize);@+break; + case b100|3: HPUT32(e->size);@+HPUT32(e->xsize);@+break; + default: QUIT("Can't happen");@+ break; + } + hput_string(e->file_name);@/ + DBGTAG(TAG(0,b),hpos);@+HPUT8(TAG(0,b)); +} + +static void hput_directory_start(void) +{ DBG(DBGDIR,"Directory Section\n"); + section_no=0; + hpos=hstart=dir[0].buffer; + hend=hstart+dir[0].bsize; +} +static void hput_directory_end(void) +{ dir[0].size=hpos-hstart; + DBG(DBGDIR,"End Directory Section size=0x%x\n",dir[0].size); +} + +static size_t hput_root(void) +{ uint8_t buffer[MAX_TAG_DISTANCE]; + size_t s; + hpos=hstart=buffer; + hend=hstart+MAX_TAG_DISTANCE; + dir[0].section_no=max_section_no; + hput_entry(&dir[0]); + s=hput_data(0, hstart,hpos-hstart); + DBG(DBGDIR,@["Writing root size=" SIZE_F "\n"@],s); + return s; +} + +extern int option_compress; +void hput_directory(void) +{ int i; + @<set the file sizes for optional sections@>@; + if (option_compress) { hcompress(1); @+hcompress(2); @+} + hput_directory_start(); + for (i=1; i<=max_section_no; i++) + { dir[i].pos=dir[i-1].pos+dir[i-1].size; + DBG(DBGDIR,"writing entry %u at 0x%" PRIx64 "\n",i, dir[i].pos); + hput_entry(&dir[i]); + } + hput_directory_end(); + if (option_compress) hcompress(0); +} + +@ + + +To conclude this section, here is the function that adds the files that +are described in the directory entries 3 and above to a \HINT\ file in short format. +Where these files are found depends on the {\tt -g} option. +With that option given, the file names of the directory entries are used unchanged. +Without that option, the files are found in the {|hin_name|\tt .abs} and {|hin_name|\tt .rel} +directories, as described in section~\secref{absrel}. + +\gdef\subcodetitle{Optional Sections}% +\putcode +@<put functions@>= +static void hput_optional_sections(void) +{ int i; + DBG(DBGDIR,"Optional Sections\n"); + for (i=3; i<=max_section_no; i++)@/ + { FILE *f; + size_t fsize; + char *file_name=dir[i].file_name; + int file_name_length=0; + DBG(DBGDIR,"file %d: %s\n",dir[i].section_no,file_name); + if (dir[i].xsize!=0) @/ + DBG(DBGDIR,"Compressing of auxiliary files currently not supported"); + @<without {\tt -g} compute a local |file_name|@>@; + f=fopen(file_name,"rb"); + if (f==NULL) QUIT("Unable to read section %d, file %s", + dir[i].section_no,file_name); + fsize=0; + while (!feof(f))@/ + { size_t s,t; + char buffer[1<<13]; /* 8kByte */ + s=fread(buffer,1,1<<13,f);@/ + t=fwrite(buffer,1,s,hout); + if (s!=t) QUIT("writing file %s",file_name); + fsize=fsize+t; + } + fclose(f); + if (fsize!=dir[i].size) + QUIT(@["File size " SIZE_F " does not match directory size %u"@],@|fsize,dir[i].size); + } +} +@ + + + +\section{Definition Section}\index{definition section} +\label{defsection} +In a typical \HINT\ file, there are many things that are used over and over again. +For example the interword glue of a specific font or the indentation of +the first line of a paragraph. The definition section contains this information so that +it can be referenced in the content section by a simple reference number. +In addition there are a few parameters that guide the routines of \TeX. +An example is the ``above display skip'', which controls the amount of white space +inserted above a displayed equation, or the ``hyphen penalty'' that tells \TeX\ +the ``\ae sthetic cost'' of ending a line with a hyphenated word. These parameters +also get their values in the definition section as explained in section~\secref{defaults}. + + +The most simple way to store these definitions is to store them in an array indexed by the +reference numbers. +To simplify the dynamic allocation of these arrays, the list of definitions +will always start with the list of maximum\index{maximum values} values: a list that contains +for each node type the maximum reference number used. + +In the long format, the definition section starts with the keyword \.{definitions}, +followed by the list of maximum values, +followed by the definitions proper. + +When writing the short format, we start by positioning the output stream at the beginning of +the definition buffer and we end with recording the size of the definition section +in the directory. + +\readcode +@s definition_section symbol +@s definition_list symbol +@s definition symbol +@s DEFINITIONS symbol +@<symbols@>= +%token DEFINITIONS "definitions" +@ + +@<scanning rules@>= +::@=definitions@> :< return DEFINITIONS; >: +@ + +@<parsing rules@>= +definition_section: START DEFINITIONS { hput_definitions_start();}@/ + max_definitions definition_list @/ + END {hput_definitions_end();}; +definition_list: @+ | definition_list def_node; +@ + +\writecode +@<write functions@>= +void hwrite_definitions_start(void) +{ section_no=1; @+hwritef("<definitions"); +} + +void hwrite_definitions_end(void) +{ hwritef("\n>\n"); +} +@ + + + +@<get functions@>= +void hget_definition_section(void) +{ DBG(DBGBASIC|DBGDEF,"Definitions\n"); + hget_section(1); + hwrite_definitions_start(); + DBG(DBGDEF,"List of maximum values\n"); + hget_max_definitions(); + @<initialize definitions@>@; + hwrite_max_definitions(); + DBG(DBGDEF,"List of definitions\n"); + while (hpos<hend) + hget_def_node(); + hwrite_definitions_end(); +} +@ + +\putcode +@<put functions@>= +void hput_definitions_start(void) +{ DBG(DBGDEF,"Definition Section\n"); + section_no=1; + hpos=hstart=dir[1].buffer; + hend=hstart+dir[1].bsize; +} +void hput_definitions_end(void) +{ dir[1].size=hpos-hstart; + DBG(DBGDEF,"End Definition Section size=0x%x\n",dir[1].size); +} +@ +\gdef\codetitle{Definitions} +\hascode +\subsection{Maximum Values}\index{maximum values} +To help implementations allocating the right amount of memory for the +definitions, the definition section starts with a list of maximum +values. For each kind of node, we store the maximum valid reference +number in the array |max_ref| which is indexed by the kind-values. +For a reference number |n| and kind-value $k$ we have +$0\le n\le |max_ref[k]|$. +To make sure that a hint file without any definitions +will work, some definitions have default values. +The initialization of default and maximum values is described +in section~\secref{defaults}. The maximum +reference number that has a default value is stored in the array +|max_default|. +We have $-1 \le |max_default[k]| \le |max_ref[k]| < 2^{16}$, +and for most $k$ even $|max_ref[k]| < 2^{8}$. +Specifying maximum values that are lower than the +default\index{default value} values is not allowed in the short +format; in the long format, lower values are silently ignored. Some +default values are permanently fixed; for example the zero glue with +reference number |zero_skip_no| must never change. The array +|max_fixed| stores the maximum reference number that has a fixed value for a +given kind. Definitions with reference numbers less or equal than the +corresponding |max_fixed[k]| number are disallowed. Usually we have +$-1 \le |max_fixed[k]| \le |max_default[k]| $, but if for a kind-value +$k$ no definitions, and hence no maximum values are allowed, we set +$|max_fixed[k]|=|0x10000|>|max_default[k]| $. + + +We use the |max_ref| array whenever we find a +reference number in the input to check if it is within the proper range. + +@<debug macros@>= +#define @[REF_RNG(K,N)@] if ((int)(N)>max_ref[K]) QUIT("Reference %d to %s out of range [0 - %d]",\ + (N),definition_name[K],max_ref[K]) +@ + +In the long format file, the list of maximum values starts with + ``\.{<max }'', then follow pairs of keywords and numbers like + ``\.{<glue 57>}'', and it ends with ``\.{>}''. In the short format, +we start the list of maximums with a |list_kind| tag and end it with +a |list_kind| tag. Each maximum value is preceded and followed by a +tag byte with the appropriate kind-value. The info value has its |b001| bit +cleared if the maximum value is in the range 0 to |0xFF| and fits into a +single byte; the info value hast its |b001| bit set if it fits into two byte. +Currently only the |label_kind| may need to use two byte. +@<debug macros@>= +#define MAX_REF(K) ((K)==label_kind?0xFFFF:0xFF) +@ + +Other info values are reserved for future extensions. +After reading the maximum values, we initialize the data structures for +the definitions. + + +\readcode +@s max_list symbol +@s max_value symbol +@s max_definitions symbol +@s MAX symbol +@<symbols@>= +%token MAX "max" +@ + +@<scanning rules@>= +::@=max@> :< return MAX; >: +@ +@<parsing rules@>= +max_definitions: START MAX max_list END @| + { @<initialize definitions@>@;@+ hput_max_definitions(); }; + +max_list:@+ | max_list START max_value END; + +max_value: FONT UNSIGNED { hset_max(font_kind,$2); } + | INTEGER UNSIGNED { hset_max(int_kind,$2); } + | DIMEN UNSIGNED { hset_max(dimen_kind,$2); } + | LIGATURE UNSIGNED { hset_max(ligature_kind,$2); } + | DISC UNSIGNED { hset_max(disc_kind,$2); } + | GLUE UNSIGNED { hset_max(glue_kind,$2); } + | LANGUAGE UNSIGNED { hset_max(language_kind,$2); } + | RULE UNSIGNED { hset_max(rule_kind,$2); } + | IMAGE UNSIGNED { hset_max(image_kind,$2); } + | LEADERS UNSIGNED { hset_max(leaders_kind,$2); } + | BASELINE UNSIGNED { hset_max(baseline_kind,$2); } + | XDIMEN UNSIGNED { hset_max(xdimen_kind,$2); } + | PARAM UNSIGNED { hset_max(param_kind,$2); } + | STREAMDEF UNSIGNED { hset_max(stream_kind,$2); } + | PAGE UNSIGNED { hset_max(page_kind,$2); } + | RANGE UNSIGNED { hset_max(range_kind,$2); } + | LABEL UNSIGNED { hset_max(label_kind,$2); }; + +@ + +@<parsing functions@>= +void hset_max(kind_t k, int n) +{ DBG(DBGDEF,"Setting max %s to %d\n",definition_name[k],n); + RNG("Maximum",n,max_fixed[k]+1,MAX_REF(k)); + if (n>max_ref[k]) + max_ref[k]=n; +} +@ + +\writecode +@<write functions@>= +void hwrite_max_definitions(void) +{ kind_t k; + hwrite_start();@+ + hwritef("max"); + for (k=0; k<32;k++) + if (max_ref[k]>max_default[k])@/ + {@+ switch (k) + { @<cases of writing special maximum values@>@; + default: + hwrite_start(); + hwritef("%s %d",definition_name[k], max_ref[k]); + hwrite_end(); + break; + } + } + hwrite_end(); +} +@ + +\getcode +@<get file functions@>= +void hget_max_definitions(void) +{ kind_t k; + @<read the start byte |a|@>@; + if (a!=TAG(list_kind,0)) QUIT("Start of maximum list expected"); + for(k= 0;k<32;k++)max_ref[k]= max_default[k]; max_outline=-1; + while (true) @/ + { int n; + if (hpos>=hend) QUIT("Unexpected end of maximum list"); + node_pos=hpos-hstart; + HGETTAG(a);@+ + k=KIND(a);@+ + if (k==list_kind) break; + if (INFO(a)&b001) HGET16(n); @+else n=HGET8; + switch (a) + { @<cases of getting special maximum values@>@; + default: + if (max_fixed[k]>max_default[k]) + QUIT("Maximum value for kind %s not supported",definition_name[k]); + RNG("Maximum number",n,max_default[k],MAX_REF(k)); + max_ref[k]=n; + DBG(DBGDEF,"max(%s) = %d\n",definition_name[k],max_ref[k]); + break; + } + @<read and check the end byte |z|@>@; + } + if (INFO(a)!=0) QUIT("End of maximum list with info %d", INFO(a)); +} +@ + +\putcode + +@<put functions@>= +void hput_max_definitions(void) +{ kind_t k; + DBG(DBGDEF,"Writing Max Definitions\n"); + HPUTTAG(list_kind,0); + for (k=0; k<32; k++) + if (max_ref[k]>max_default[k]) + { uint32_t pos=hpos++-hstart; + DBG(DBGDEF,"max(%s) = %d\n",definition_name[k],max_ref[k]); + hput_tags(pos,TAG(k,hput_n(max_ref[k])-1)); + } + @<cases of putting special maximum values@>@; + HPUTTAG(list_kind,0); + DBG(DBGDEF,"Writing Max Definitions End\n"); +} +@ + + +\subsection{Definitions}\label{definitions} +A definition\index{definition section} associates a reference number +with a content node. Here is an example: A glue definition associates +a glue number, for example 71, with a glue specification. In the long +format this might look like ``{\tt \.{<}glue *71 4pt plus 5pt minus +0.5pt\.{>}}'' which makes glue number 71 refer to a 4pt glue with a +stretchability of 5pt and a shrinkability of 0.5pt. +Such a glue definition differs from a normal glue node just by an extra +byte value immediately following the keyword respectively start byte. + +Whenever we need this glue in the content section, we can say +``{\tt \.{<}glue *71\.{>}}''. Because we restrict the number of glue definitions +to at most 256, a single byte is sufficient to +store the reference number. The \.{shrink} and \.{stretch} programs +will, however, not bother to store glue definitions. Instead they will +write them in the new format immediately to the output. + +The parser will handle definitions in any order, but the order is relevant +if a definition references another definition, and of course, +it never does any harm to present definitions in a systematic way. + +As a rule, the definition of a reference must always precede the +use of that reference. While this is always the case for +references in the content section, it restricts the use of +references inside the definition section. + +The definitions for integers, dimensions, extended dimensions, + languages, rules, ligatures, and images are ``simple''. +They never contain references and so it is always possible to list them first. +The definition of glues may contain extended dimensions, +the definitions of baselines may reference glue nodes, and +the definitions of parameter lists contain definitions of integers, dimensions, +and glues. So these definitions should follow in this order. + +The definitions of leaders and discretionary breaks allow boxes. +While these boxes are usually +quite simple, they may contain arbitrary references---including again +references to leaders and discretionary breaks. So, at least in principle, +they might impose complex (or even unsatisfiable) restrictions +on the order of those definitions. + +The definitions of fonts contain not only ``simple'' definitions +but also the definitions of interword glues and hyphens +introducing additional ordering restrictions. +The definition of hyphens regularly contain glyphs which in turn reference +a font---typically the font that just gets defined. +Therefore we relax the define before use policy for glyphs: +Glyphs may reference a font before the font is defined. + +The definitions of page templates contain lists of arbitrary content +nodes, and while the boxes inside leaders or discretionary breaks tend to be simple, +the content of page templates is often quite complex. +Page templates are probably the source of most ordering restrictions. +Placing page templates towards the end of the list of definitions +might be a good idea. +% +A special case are stream definitions. These occur only as part of +the corresponding page template definition and are listed at its end. +So references to them will occur in the page template always before their +definition. +% +Finally, the definitions of page ranges always reference a page template +and they should come after the page template definitions. +For technical reasons explained in section~\secref{labels}, +definitions of labels and outlines come last. + +To avoid complex dependencies, an application can always choose not to +use references in the definition section. There are only three types of +nodes where references can not be avoided: fonts are referenced in glyph nodes, +labels are referenced in outlines, +and languages are referenced in boxes or page templates. +Possible ordering restrictions can be satisfied if languages are defined early. +To check the define before use policy, we use an array of bitvectors, +but we limit checking to the first 256 references. +We have for every reference number $|N|<256$ and every kind |K| a single +bit which is set if and only if the corresponding reference is defined. + +@<definition checks@>= +uint32_t definition_bits[0x100/32][32]={{0}}; + +#define @[SET_DBIT(N,K)@] ((N)>0xFF?1:(definition_bits[N/32][K]|=(1<<((N)&(32-1))))) +#define @[GET_DBIT(N,K)@] ((N)>0xFF?1:((definition_bits[N/32][K]>>((N)&(32-1)))&1)) +#define @[DEF(D,K,N)@] (D).k=K;@+ (D).n=(N);@+SET_DBIT((D).n,(D).k);\ + DBG(DBGDEF,"Defining %s %d\n",definition_name[(D).k],(D).n);\ + RNG("Definition",(D).n,max_fixed[(D).k]+1,max_ref[(D).k]); +#define @[REF(K,N)@] REF_RNG(K,N);if(!GET_DBIT(N,K)) \ + QUIT("Reference %d to %s before definition",(N),definition_name[K]) +@ + +@<initialize definitions@>= +definition_bits[0][int_kind]=(1<<(MAX_INT_DEFAULT+1))-1; +definition_bits[0][dimen_kind]=(1<<(MAX_DIMEN_DEFAULT+1))-1; +definition_bits[0][xdimen_kind]=(1<<(MAX_XDIMEN_DEFAULT+1))-1; +definition_bits[0][glue_kind]=(1<<(MAX_GLUE_DEFAULT+1))-1; +definition_bits[0][baseline_kind]=(1<<(MAX_BASELINE_DEFAULT+1))-1; +definition_bits[0][page_kind]=(1<<(MAX_PAGE_DEFAULT+1))-1; +definition_bits[0][stream_kind]=(1<<(MAX_STREAM_DEFAULT+1))-1; +definition_bits[0][range_kind]=(1<<(MAX_RANGE_DEFAULT+1))-1; +@ + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + + +@s font symbol +@<symbols@>= + +%type <rf> def_node +@ + +@<parsing rules@>= +def_node: + start FONT ref font END @| { DEF($$,font_kind,$3);@+ hput_tags($1,$4);@+} +| start INTEGER ref integer END @| { DEF($$,int_kind,$3);@+ hput_tags($1,hput_int($4));@+} +| start DIMEN ref dimension END @| { DEF($$,dimen_kind,$3);@+ hput_tags($1,hput_dimen($4));} +| start LANGUAGE ref string END @| { DEF($$,language_kind,$3);@+hput_string($4); hput_tags($1,TAG(language_kind,0));} +| start GLUE ref glue END @| { DEF($$,glue_kind,$3);@+ hput_tags($1,hput_glue(&($4)));} +| start XDIMEN ref xdimen END @| { DEF($$,xdimen_kind,$3);@+ hput_tags($1,hput_xdimen(&($4)));} +| start RULE ref rule END @| { DEF($$,rule_kind,$3);@+ hput_tags($1,hput_rule(&($4)));} +| start LEADERS ref leaders END @| { DEF($$,leaders_kind,$3);@+ hput_tags($1,TAG(leaders_kind, $4));} +| start BASELINE ref baseline END @| { DEF($$,baseline_kind,$3);@+hput_tags($1,TAG(baseline_kind, $4));@+} +| start LIGATURE ref ligature END @| { DEF($$,ligature_kind,$3);@+hput_tags($1,hput_ligature(&($4)));} +| start DISC ref disc END @| { DEF($$,disc_kind,$3);@+ hput_tags($1,hput_disc(&($4)));} +| start IMAGE ref image END @| { DEF($$,image_kind,$3);@+ hput_tags($1,hput_image(&($4)));} +| start PARAM ref parameters END @| { DEF($$,param_kind,$3);@+ hput_tags($1,hput_list($1+2,&($4)));} +| start PAGE ref page END @| { DEF($$,page_kind,$3);@+ hput_tags($1,TAG(page_kind,0));}; +@ + +There are a few cases where one wants to define a reference by a reference. +For example, a \HINT\ file may want to set the {\tt parfillskip} glue to zero. +While there are multiple ways to define the zero glue, the canonical way is a reference +using the |zero_glue_no|. All these cases have in common that the reference to be defined +is one of the default references and the defining reference is one of the fixed references. +We add a few parsing rules and a testing macro for those cases where the number +of default definitions is greater than the number of fixed definitions. + +@<definition checks@>= +#define @[DEF_REF(D,K,M,N)@] DEF(D,K,M);\ +if ((M)>max_default[K]) QUIT("Defining non default reference %d for %s",M,definition_name[K]); \ +if ((N)>max_fixed[K]) QUIT("Defining reference %d for %s by non fixed reference %d",M,definition_name[K],N); +@ + +@<parsing rules@>= +def_node: + start INTEGER ref ref END @/{DEF_REF($$,int_kind,$3,$4); hput_tags($1,TAG(int_kind,0)); } +| start DIMEN ref ref END @/{DEF_REF($$,dimen_kind,$3,$4); hput_tags($1,TAG(dimen_kind,0)); } +| start GLUE ref ref END @/{DEF_REF($$,glue_kind,$3,$4); hput_tags($1,TAG(glue_kind,0)); }; +@ + + + + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} + +@<get functions@>= +void hget_definition(int n, uint8_t a, uint32_t node_pos) +{@+ switch(KIND(a)) + { case font_kind: hget_font_def(n);@+ break; + case param_kind: + {@+ list_t l; @+HGET_LIST(INFO(a),l); @+hwrite_parameters(&l); @+ break;@+} + case page_kind: hget_page(); @+break; + case dimen_kind: hget_dimen(a); @+break; + case xdimen_kind: + {@+ xdimen_t x; @+hget_xdimen(a,&x); @+hwrite_xdimen(&x); @+break;@+ } + case language_kind: + if (INFO(a)!=b000) + QUIT("Info value of language definition must be zero"); + else + { char *n; HGET_STRING(n);@+ hwrite_string(n); } + break; + default: + hget_content(a); @+break; + } +} + + +void hget_def_node() +{ kind_t k; + + @<read the start byte |a|@>@; + k=KIND(a); + if (k==label_kind) + hget_outline_or_label_def(INFO(a),node_pos); + else + { int n; + n=HGET8; + if (k!=range_kind) REF_RNG(k,n); + SET_DBIT(n,k); + if (k==range_kind) + hget_range(INFO(a),n); + else + { hwrite_start(); @+hwritef("%s *%d",definition_name[k],n); + hget_definition(n,a,node_pos); + hwrite_end(); + } + if(n>max_ref[k] || n <= max_fixed[k]) + QUIT("Definition %d for %s out of range [%d - %d]",@| + n, definition_name[k],max_fixed[k]+1,max_ref[k]); + } + if (max_fixed[k]>max_default[k]) + QUIT("Definitions for kind %s not supported", definition_name[k]); + @<read and check the end byte |z|@>@; +} +@ + + + +\subsection{Parameter Lists}\label{paramlist}\index{parameter list} +Because the content section is a ``stateless'' list of nodes, the +definitions we see in the definition section can never change. It is +however necessary to make occasionally local modifications of some of +these definitions, because some definitions are parameters of the +algorithms borrowed from \TeX. Nodes that need such modifications, for +example the paragraph nodes that are passed to \TeX's line breaking +algorithm, contain a list of local definitions called parameters. +Typically sets of related parameters are needed. To facilitate a +simple reference to such a set of parameters, we allow predefined +parameter lists that can be referenced by a single number. The +parameters of \TeX's routines are quite basic---integers\index{integer}, +dimensions\index{dimension}, and glues\index{glue}---and all +of them have default values. +Therefore we restrict the definitions in parameter lists to such +basic definitions. + +@<parsing functions@>= +void check_param_def(ref_t *df) +{ if(df->k!=int_kind && df->k!=dimen_kind && @| df->k!=glue_kind) + QUIT("Kind %s not allowed in parameter list", definition_name[df->k]); + if(df->n<=max_fixed[df->k] || max_default[df->k]<df->n) + QUIT("Parameter %d for %s not allowed in parameter list", df->n, definition_name[df->k]); +} +@ + +The definitions below repeat the definitions we have seen for lists in section~\secref{plainlists} +with small modifications. For example we use the kind-value |param_kind|. An empty parameter list +is omitted in the long format as well as in the short format. + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + +@s PARAM symbol +@s def_list symbol +@s parameters_node symbol +@s def_node symbol +@s parameters symbol +@s empty_param_list symbol +@s non_empty_param_list symbol + +@<symbols@>= +%token PARAM "param" +%type <u> def_list +%type <l> parameters +@ + +@<scanning rules@>= +::@=param@> :< return PARAM; >: +@ +@<parsing rules@>= +def_list: position @+ + | def_list def_node {check_param_def(&($2));}; +parameters: estimate def_list { $$.p=$2; $$.k=param_kind; $$.s=(hpos-hstart)-$2;}; +@ + +Using a parsing rule like +``\nts{param\_list}: \nts{start} \ts{PARAM} \nts{parameters} \ts{END}'', +an empty parameter list will be written as ``\.{<param>}''. +This looks ugly and seems like unnecessary syntax. It would be nicer +if an empty parameter list could simply be omitted. +Generating an empty parameter list for an omitted parameter list +is however a bit tricky. +Consider the sequence ``\.{<param\dots>} \.{<hbox\dots>}'' versus +the sequence ``\.{<hbox\dots>}''. In the latter case, +the parser will notice the missing parameter list +when it encounters the \.{hbox} token. +Of course it is not a good idea to augment the rules for the \.{hbox} with +a special test for the missing empty parameter list. +It is better to insert an empty parameter list before parsing the first ``\.{<}'' token +and remove it again if a non-empty parameter list has been detected. +This can be accomplished by the following two rules. + +@<parsing rules@>= +empty_param_list: position { HPUTX(2); hpos++; hput_tags($1,TAG(param_kind,1));}; +non_empty_param_list: start PARAM {hpos=hpos-2;} parameters END @/ + { @+ hput_tags($1-2,hput_list($1-1,&($4)));@+}; +@ + +\writecode +@<write functions@>= +void hwrite_parameters(list_t *l) +{ uint32_t h=hpos-hstart, e=hend-hstart; /* save |hpos| and |hend| */ + hpos=l->p+hstart;@+ hend=hpos+l->s; + if (l->s>0xFF) hwritef(" %d",l->s); + while(hpos<hend) hget_def_node(); + hpos=hstart+h;@+ hend=hstart+e; /* restore |hpos| and |hend| */ +} +void hwrite_param_list(list_t *l) +{ @+if (l->s!=0) @/ + { hwrite_start();@+ + hwritef("param"); + hwrite_parameters(l); + hwrite_end(); + } +} +@ + +\getcode +@<get functions@>= +void hget_param_list(list_t *l) +{ @+if (KIND(*hpos)!=param_kind) @/ + QUIT("Parameter list expected at 0x%x", (uint32_t)(hpos-hstart)); + else hget_list(l); +} +@ + + + +\subsection{Fonts}\label{fonts} +Another definition that has no corresponding content node is the +font\index{font} definition. Fonts by themselves do not constitute +content, instead they are used in glyph\index{glyph} nodes. +Further, fonts are never directly embedded in a content node; in a content node, a +font is always specified by its font number. This limits the number of +fonts that can be used in a \HINT\ file to at most 256. + +A long format font definition starts with the keyword ``\.{font}'' and +is followed by the font number, as usual prefixed by an asterisk. Then +comes the font specification with the font size, the font +name, the section number of the \TeX\ font metric file, and the +section number of the file containing the glyphs for the font. +The \HINT\ format supports \.{.pk} files, the traditional font format +for \TeX, and the more modern PostScript Type 1 fonts, +TrueType fonts, and OpenType fonts. + +The format of font definitions will probably change in future +versions of the \HINT\ file format. +For example, \.{.pk} files might be replaced entirely by PostScript Type 1 fonts. +Also \HINT\ needs the \TeX\ font metric files only to obtain the sizes +of characters when running \TeX's line breaking algorithm. +But for many TrueType fonts there are no \TeX\ font metric files, +while the necessary information about character sizes should be easy +to obtain. +Another information, that is currently missing from font definitions, +is the fonts character encoding. + +In a \HINT\ file, text is represented as a sequence of numbers called +character codes. \HINT\ files use the UTF-8 character encoding +scheme (CES) to map these numbers to their representation as byte +sequences. For example the number ``|0xE4|'' is encoded as the byte +sequence ``|0xC3| |0xA4|''. The same number |0xE4| now can represent +different characters depending on the coded character set (CCS). For +example in the common ISO-8859-1 (Latin 1) encoding the number |0xE4| +is the umlaut ``\"a'' where as in the ISO-8859-7 (Latin/Greek) it is +the Greek letter ``$\delta$'' and in the EBCDIC encoding, used on IBM +mainframes, it is the upper case letter ``U''. + +The character encoding is +irrelevant for rendering a \HINT\ file as long as the character codes +in the glyph nodes are consistent with the character codes used in the font +file, but the character encoding is necessary for all programs that +need to ``understand'' the content of the \HINT\ file. For example +programs that want to translate a \HINT\ document to a different language, +or for text-to-speech conversion. + +The Internet Engineering Task Force IETF has established a character set +registry\cite{ietf:charset-mib} that defines an enumeration of all +registered coded character sets\cite{iana:charset-mib}. The coded +character set numbers are in the range 1--2999. +This encoding number, as given in~\cite{iana:charset}, +might be one possibility for specifying the font encoding as +part of a font definition. + +Currently, it is only required that a font specifies +an interword glue and a default discretionary break. After that comes +a list of up to 12 font specific parameters. + +The font size specifies the desired ``at size''\index{font at size} +which might be different from the ``design size''\index{font design size} +of the font as stored in the \.{.tfm} file. + +In the short format, the font specification is given in the same order +as in the long format. + +Our internal representation of a font just stores the font name +because in the long format we add the font name as a comment to glyph +nodes. + + +@<common variables@>= +char **hfont_name; /* dynamically allocated array of font names */ +@ + +@<hint basic types@>= +#define MAX_FONT_PARAMS 11 +@ + +@<initialize definitions@>= +ALLOCATE(hfont_name,max_ref[font_kind]+1,char *); +@ + + + +\readcode +@s FONT symbol +@s fref symbol +@s font_param_list symbol +@s font_param symbol +@s font_head symbol + +@<symbols@>= +%token FONT "font" +%type <info> font font_head +@ + +@<scanning rules@>= +::@=font@> :< return FONT; >: +@ + +Note that we set the definition bit early because the definition of font |f| +might involve glyphs that reference font |f| (or other fonts). + +@<parsing rules@>=@/ + +font: font_head font_param_list; + +font_head: string dimension UNSIGNED UNSIGNED @/ + {uint8_t f=$<u>@&0; SET_DBIT(f,font_kind); @+hfont_name[f]=strdup($1); $$=hput_font_head(f,hfont_name[f],$2,$3,$4);}; + +font_param_list: glue_node disc_node @+ | font_param_list font_param ; + +font_param: @/ + start PENALTY fref penalty END { hput_tags($1,hput_int($4));} +| start KERN fref kern END { hput_tags($1,hput_kern(&($4)));} +| start LIGATURE fref ligature END { hput_tags($1,hput_ligature(&($4)));} +| start DISC fref disc END { hput_tags($1,hput_disc(&($4)));} +| start GLUE fref glue END { hput_tags($1,hput_glue(&($4)));} +| start LANGUAGE fref string END { hput_string($4);hput_tags($1,TAG(language_kind,0));} +| start RULE fref rule END { hput_tags($1,hput_rule(&($4)));} +| start IMAGE fref image END { hput_tags($1,hput_image(&($4)));}; + +fref: ref @/{ RNG("Font parameter",$1,0,MAX_FONT_PARAMS); }; +@ + +\goodbreak +\vbox{\getcode\vskip -\baselineskip\writecode} + +@<get functions@>= +static void hget_font_params(void) +{ disc_t h; + hget_glue_node(); + hget_disc_node(&(h));@+ hwrite_disc_node(&h); + DBG(DBGDEF,"Start font parameters\n"); + while (KIND(*hpos)!=font_kind)@/ + { ref_t df; + @<read the start byte |a|@>@; + df.k=KIND(a); + df.n=HGET8; + DBG(DBGDEF,"Reading font parameter %d: %s\n",df.n, definition_name[df.k]); + if (df.k!=penalty_kind && df.k!=kern_kind && df.k!=ligature_kind && @| + df.k!=disc_kind && df.k!=glue_kind && df.k!=language_kind && @| df.k!=rule_kind && df.k!=image_kind) + QUIT("Font parameter %d has invalid type %s",df.n, content_name[df.n]); + RNG("Font parameter",df.n,0,MAX_FONT_PARAMS); + hwrite_start(); @+ hwritef("%s *%d",content_name[KIND(a)],df.n); + hget_definition(df.n,a,node_pos); + hwrite_end(); + @<read and check the end byte |z|@>@; + } + DBG(DBGDEF,"End font parameters\n"); +} + + +void hget_font_def(uint8_t f) +{ char *n; @+dimen_t s=0;@+uint16_t m,y; + HGET_STRING(n);@+ hwrite_string(n);@+ hfont_name[f]=strdup(n); + HGET32(s); @+ hwrite_dimension(s); + DBG(DBGDEF,"Font %s size 0x%x\n", n, s); + HGET16(m); @+RNG("Font metrics",m,3,max_section_no); + HGET16(y); @+RNG("Font glyphs",y,3,max_section_no); + hwritef(" %d %d",m,y); + hget_font_params(); + DBG(DBGDEF,"End font definition\n"); +} +@ + +\putcode +@<put functions@>= +uint8_t hput_font_head(uint8_t f, char *n, dimen_t s, @| uint16_t m, uint16_t y) +{ info_t i=b000; + DBG(DBGDEF,"Defining font %d (%s) size 0x%x\n", f, n, s); + hput_string(n); + HPUT32(s);@+ + HPUT16(m); @+HPUT16(y); + return TAG(font_kind,i); +} +@ + + + +\subsection{References}\label{reference} +We have seen how to make definitions, now let's see how to +reference\index{reference} them. In the long form, we can simply +write the reference number, after the keyword like this: +``{\tt \.{<}glue *17\.{>}}''. +The asterisk\index{asterisk} is necessary to keep apart, +for example, a penalty with value 50, +written ``{\tt \.{<}penalty 50\.{>}}'', +from a penalty referencing the integer +definition number 50, written ``{\tt \.{<}penalty *50\.{>}}''. + +\goodbreak +\vbox{\readcode\vskip -\baselineskip\putcode} + +@<parsing rules@>= +xdimen_ref: ref { REF(xdimen_kind,$1);}; +param_ref: ref { REF(param_kind,$1); }; +stream_ref: ref { REF_RNG(stream_kind,$1); }; + + +content_node: + start PENALTY ref END @/{ REF(penalty_kind,$3); @+ hput_tags($1,TAG(penalty_kind,0)); } +|start KERN explicit ref END @/ + { REF(dimen_kind,$4); @+ hput_tags($1,TAG(kern_kind,($3)?b100:b000)); } +|start KERN explicit XDIMEN ref END @/ + { REF(xdimen_kind,$5); @+hput_tags($1,TAG(kern_kind,($3)?b101:b001)); } +|start GLUE ref END @/{ REF(glue_kind,$3); @+ hput_tags($1,TAG(glue_kind,0)); } +|start LIGATURE ref END @/{ REF(ligature_kind,$3); @+ hput_tags($1,TAG(ligature_kind,0)); } +|start DISC ref END @/{ REF(disc_kind,$3); @+ hput_tags($1,TAG(disc_kind,0)); } +|start RULE ref END @/{ REF(rule_kind,$3); @+ hput_tags($1,TAG(rule_kind,0)); } +|start IMAGE ref END @/{ REF(image_kind,$3);@+ hput_tags($1,TAG(image_kind,0)); } +|start LEADERS ref END @/{ REF(leaders_kind,$3); @+ hput_tags($1,TAG(leaders_kind,0)); } +|start BASELINE ref END @/{ REF(baseline_kind,$3);@+ hput_tags($1,TAG(baseline_kind,0)); } +|start LANGUAGE REFERENCE END @/{ REF(language_kind,$3);@+ hput_tags($1,hput_language($3)); }; + +glue_node: start GLUE ref END @/{ REF(glue_kind,$3); +if ($3==zero_skip_no) { hpos=hpos-2; $$=false;@+ } +else {hput_tags($1,TAG(glue_kind,0)); $$=true;@t\2@>@+}}; + +@ + +\getcode +@<cases to get content@>= +@t\1\kern1em@> +case TAG(penalty_kind,0): HGET_REF(penalty_kind); @+break; +case TAG(kern_kind,b000): HGET_REF(dimen_kind); @+break; +case TAG(kern_kind,b100): hwritef(" !"); @+HGET_REF(dimen_kind); @+break; +case TAG(kern_kind,b001): @| hwritef(" xdimen");@+ HGET_REF(xdimen_kind); @+break; +case TAG(kern_kind,b101): @| hwritef(" ! xdimen");@+ HGET_REF(xdimen_kind); @+break; +case TAG(ligature_kind,0): HGET_REF(ligature_kind); @+break; +case TAG(disc_kind,0): HGET_REF(disc_kind); @+break; +case TAG(glue_kind,0): HGET_REF(glue_kind); @+break; +case TAG(language_kind,b000): HGET_REF(language_kind); @+break; +case TAG(rule_kind,0): HGET_REF(rule_kind); @+break; +case TAG(image_kind,0): HGET_REF(image_kind); @+break; +case TAG(leaders_kind,0): HGET_REF(leaders_kind); @+break; +case TAG(baseline_kind,0): HGET_REF(baseline_kind); @+break; +@ + +@<get macros@>= +#define @[HGET_REF(K)@] {uint8_t n=HGET8;@+ REF(K,n); @+hwrite_ref(n);@+} +@ +\writecode +@<write functions@>= +void hwrite_ref(int n) +{hwritef(" *%d",n);@+} + +void hwrite_ref_node(kind_t k, uint8_t n) +{ hwrite_start(); @+hwritef("%s",content_name[k]);@+ hwrite_ref(n); @+hwrite_end();} +@ + + + +\section{Defaults}\label{defaults}\index{default value} +Several of the predefined values found in the definition section are used +as parameters for the routines borrowed from \TeX\ to display the content +of a \HINT\ file. These values must be defined, but it is inconvenient if +the same standard definitions need to be placed in each and every \HINT\ file. +Therefore we specify in this chapter reasonable default values. +As a consequence, even a \HINT\ file without any definitions should +produce sensible results when displayed. + +The definitions that have default values are integers, dimensions, +extended dimensions, glues, baselines, labels, page templates, +streams, and page ranges. +Each of these defaults has its own subsection below. +Actually the defaults for extended dimensions, baselines, and labels + are not needed by \TeX's routines, but it is nice to have default +values for the extended dimensions that represent +\.{hsize}, \.{vsize}, a zero baseline skip, and a label for the table +of content. + +The array |max_default| contains for each kind-value the maximum number of +the default values. The function |hset_max| is used to initialize them. + +The programs \.{shrink} and \.{stretch} actually do not use the defaults, +but it would be possible to suppress definitions if the defined value +is the same as the default value. +% +We start by setting |max_default[k]==-1|, meaning no defaults, +and |max_fixed[k]==0x10000|, meaning no definitions. +The following subsections will then overwrite these values for +all kinds of definitions that have defaults. +It remains to reset |max_fixed| to $-1$ for all those kinds +that have no defaults but allow definitions. + +@<take care of variables without defaults@>= + for (k=0; k<32; k++) max_default[k]=-1,max_fixed[k]=0x10000; + @/@t}$\hangindent=1em${@>max_fixed[font_kind]= max_fixed[ligature_kind]= max_fixed[disc_kind] + @|=max_fixed[language_kind]=max_fixed[rule_kind]= max_fixed[image_kind] + @|= max_fixed[leaders_kind]= max_fixed[param_kind]=max_fixed[label_kind]@|= -1; +@ + + +\subsection{Integers} +Integers\index{integer} are very simple objects, and it might be tempting not to +use predefined integers at all. But the \TeX\ typesetting engine, +which is used by \HINT, uses many integer parameters to fine tune +its operations. As we will see, all these integer parameters have a predefined +integer number that refers to an integer definition. + +Integers and penalties\index{penalty} share the same kind-value. So a penalty node that references +one of the predefined penalties, simply contains the integer number as a reference +number. + +The following integer numbers are predefined. +The zero integer is fixed with integer number zero. %It is never redefined. +The default values are taken from {\tt plain.tex}. + +@<default names@>= +typedef enum {@t}$\hangindent=2em${@> + zero_int_no=0, + pretolerance_no=1, + tolerance_no=2, + line_penalty_no=3, + hyphen_penalty_no=4, + ex_hyphen_penalty_no=5, + club_penalty_no=6, + widow_penalty_no=7, + display_widow_penalty_no=8, + broken_penalty_no=9, + pre_display_penalty_no=10, + post_display_penalty_no=11, + inter_line_penalty_no=12, + double_hyphen_demerits_no=13, + final_hyphen_demerits_no=14, + adj_demerits_no=15, + looseness_no=16, + time_no=17, + day_no=18, + month_no=19, + year_no=20, + hang_after_no=21, + floating_penalty_no=22 +} int_no_t; +#define MAX_INT_DEFAULT floating_penalty_no +@ + +@<define |int_defaults|@>= +max_default[int_kind]=MAX_INT_DEFAULT; +max_fixed[int_kind]=zero_int_no; +int_defaults[zero_int_no]=0; +int_defaults[pretolerance_no]=100; +int_defaults[tolerance_no]=200; +int_defaults[line_penalty_no]=10; +int_defaults[hyphen_penalty_no]=50; +int_defaults[ex_hyphen_penalty_no]=50; +int_defaults[club_penalty_no]=150; +int_defaults[widow_penalty_no]=150; +int_defaults[display_widow_penalty_no]=50; +int_defaults[broken_penalty_no]=100; +int_defaults[pre_display_penalty_no]=10000; +int_defaults[post_display_penalty_no]=0; +int_defaults[inter_line_penalty_no]=0; +int_defaults[double_hyphen_demerits_no]=10000; +int_defaults[final_hyphen_demerits_no]=5000; +int_defaults[adj_demerits_no]=10000; +int_defaults[looseness_no]=0; +int_defaults[time_no]=720; +int_defaults[day_no]=4; +int_defaults[month_no]=7; +int_defaults[year_no]=1776; +int_defaults[hang_after_no]=1; +int_defaults[floating_penalty_no]=20000; +@# + +printf("int32_t int_defaults[MAX_INT_DEFAULT+1]={"); +for (i=0; i<= max_default[int_kind];i++)@/ +{ printf("%d",int_defaults[i]);@+ + if (i<max_default[int_kind]) printf(", ");@+ +} +printf("};\n\n"); +@ + +\subsection{Dimensions} + +Notice that there are default values for the two dimensions \.{hsize} and \.{vsize}. +These are the ``design sizes'' for the hint file. While it might not be possible +to display the \HINT\ file using these values of \.{hsize} and \.{vsize}, +these are the author's recommendation for the best ``viewing experience''. + +\noindent +@<default names@>= +typedef enum {@t}$\hangindent=2em${@> +zero_dimen_no=0, +hsize_dimen_no=1, +vsize_dimen_no=2, +line_skip_limit_no=3, +max_depth_no=4, +split_max_depth_no=5, +hang_indent_no=6, +emergency_stretch_no=7, +quad_no=8, +math_quad_no=9 +} dimen_no_t; +#define MAX_DIMEN_DEFAULT math_quad_no +@ + +@<define |dimen_defaults|@>= +max_default[dimen_kind]=MAX_DIMEN_DEFAULT; +max_fixed[dimen_kind]=zero_dimen_no;@# +dimen_defaults[zero_dimen_no]=0; +dimen_defaults[hsize_dimen_no]=(dimen_t)(6.5*72.27*ONE); +dimen_defaults[vsize_dimen_no]=(dimen_t)(8.9*72.27*ONE); +dimen_defaults[line_skip_limit_no]=0; +dimen_defaults[split_max_depth_no]=(dimen_t)(3.5*ONE); +dimen_defaults[hang_indent_no]=0; +dimen_defaults[emergency_stretch_no]=0; +dimen_defaults[quad_no]=10*ONE; +dimen_defaults[math_quad_no]=10*ONE;@# + +printf("dimen_t dimen_defaults[MAX_DIMEN_DEFAULT+1]={"); +for (i=0; i<= max_default[dimen_kind];i++) +{ printf("0x%x",dimen_defaults[i]); + if (i<max_default[dimen_kind]) printf(", "); +} +printf("};\n\n"); +@ + +\subsection{Extended Dimensions} +Extended dimensions\index{extended dimension} can be used in a variety of nodes for example +kern\index{kern} and box\index{box} nodes. +We define three fixed extended dimensions: zero, hsize, and vsize. +In contrast to the \.{hsize} and \.{vsize} dimensions defined in the previous +section, the extended dimensions defined here are linear functions that always evaluate +to the current horizontal and vertical size in the viewer. + +@<default names@>= +typedef enum { +zero_xdimen_no=0, +hsize_xdimen_no=1, +vsize_xdimen_no=2 +} xdimen_no_t; +#define MAX_XDIMEN_DEFAULT vsize_xdimen_no +@ + +@<define |xdimen_defaults|@>= +max_default[xdimen_kind]=MAX_XDIMEN_DEFAULT; +max_fixed[xdimen_kind]=vsize_xdimen_no;@# + +printf("xdimen_t xdimen_defaults[MAX_XDIMEN_DEFAULT+1]={"@/ +"{0x0, 0.0, 0.0}, {0x0, 1.0, 0.0}, {0x0, 0.0, 1.0}"@/ +"};\n\n"); +@ + + +\subsection{Glue} + +There are predefined glue\index{glue} numbers that correspond to the skip parameters of \TeX. +The default values are taken from {\tt plain.tex}. + +@<default names@>= +typedef enum {@t}$\hangindent=2em${@> +zero_skip_no=0, +fil_skip_no=1, +fill_skip_no=2, +line_skip_no=3, +baseline_skip_no=4, +above_display_skip_no=5, +below_display_skip_no=6, +above_display_short_skip_no=7, +below_display_short_skip_no=8, +left_skip_no=9, +right_skip_no=10, +top_skip_no=11, +split_top_skip_no=12, +tab_skip_no=13, +par_fill_skip_no=14 +} glue_no_t; +#define MAX_GLUE_DEFAULT par_fill_skip_no +@ + +@<define |glue_defaults|@>= +max_default[glue_kind]=MAX_GLUE_DEFAULT; +max_fixed[glue_kind]=fill_skip_no; + +glue_defaults[fil_skip_no].p.f=1.0; +glue_defaults[fil_skip_no].p.o=fil_o; + +glue_defaults[fill_skip_no].p.f=1.0; +glue_defaults[fill_skip_no].p.o=fill_o;@# + +glue_defaults[line_skip_no].w.w=1*ONE; +glue_defaults[baseline_skip_no].w.w=12*ONE; + +glue_defaults[above_display_skip_no].w.w=12*ONE; +glue_defaults[above_display_skip_no].p.f=3.0; +glue_defaults[above_display_skip_no].p.o=normal_o; +glue_defaults[above_display_skip_no].m.f=9.0; +glue_defaults[above_display_skip_no].m.o=normal_o; + +glue_defaults[below_display_skip_no].w.w=12*ONE; +glue_defaults[below_display_skip_no].p.f=3.0; +glue_defaults[below_display_skip_no].p.o=normal_o; +glue_defaults[below_display_skip_no].m.f=9.0; +glue_defaults[below_display_skip_no].m.o=normal_o; + +glue_defaults[above_display_short_skip_no].p.f=3.0; +glue_defaults[above_display_short_skip_no].p.o=normal_o; + +glue_defaults[below_display_short_skip_no].w.w=7*ONE; +glue_defaults[below_display_short_skip_no].p.f=3.0; +glue_defaults[below_display_short_skip_no].p.o=normal_o; +glue_defaults[below_display_short_skip_no].m.f=4.0; +glue_defaults[below_display_short_skip_no].m.o=normal_o; + +glue_defaults[top_skip_no].w.w=10*ONE; +glue_defaults[split_top_skip_no].w.w=(dimen_t)8.5*ONE; + +glue_defaults[par_fill_skip_no].p.f=1.0; +glue_defaults[par_fill_skip_no].p.o=fil_o; + +#define @[PRINT_GLUE(G)@] \ + @[printf("{{0x%x, %f, %f},{%f, %d},{%f, %d}}",\ + G.w.w, G.w.h, G.w.v, G.p.f, G.p.o, G.m.f,G.m.o)@]@# + +printf("glue_t glue_defaults[MAX_GLUE_DEFAULT+1]={\n"); +for (i=0; i<= max_default[glue_kind];i++)@/ +{ PRINT_GLUE(glue_defaults[i]); @+ + if (i<max_default[int_kind]) printf(",\n"); +} +printf("};\n\n"); +@ + +We fix the glue definition with number zero to be the ``zero glue'': a +glue with width zero and zero stretchability and shrinkability. Here +is the reason: In the short format, the info bits of a glue node +indicate which components of a glue are nonzero. Therefore the zero +glue should have an info value of zero---which on the other hand is +reserved for a reference to a glue definition. Hence, the best way to +represent a zero glue is as a predefined glue. + + +\subsection{Baseline Skips} + +The zero baseline\index{baseline skip} which inserts no baseline skip is predefined. + +@<default names@>= +typedef enum {@+ +zero_baseline_no=0@+ +} baseline_no_t; +#define MAX_BASELINE_DEFAULT zero_baseline_no +@ +@<define |baseline_defaults|@>= +max_default[baseline_kind]=MAX_BASELINE_DEFAULT; +max_fixed[baseline_kind]=zero_baseline_no;@# +{ baseline_t z={{{0}}}; + printf("baseline_t baseline_defaults[MAX_BASELINE_DEFAULT+1]={{"); + PRINT_GLUE(z.bs); @+printf(", "); @+PRINT_GLUE(z.ls); printf(", 0x%x}};\n\n",z.lsl); +} +@ + +\subsection{Labels} +The zero label\index{label} is predefined. It should point to the +``home'' position of the document which should be the position +where a user can start reading or navigating the document. +For a short document this is usually the start of the document, +and hence, the default is the first position of the content section. +For a larger document, the home position could point to the +table of content where a reader will find links to other parts +of the document. + +@<default names@>= +typedef enum {@+ +zero_label_no=0@+ +} label_no_t; +#define MAX_LABEL_DEFAULT zero_label_no +@ +@<define |label_defaults|@>= +max_default[label_kind]=MAX_LABEL_DEFAULT; +printf("label_t label_defaults[MAX_LABEL_DEFAULT+1]="@|"{{0,LABEL_TOP,true,0,0,0}};\n\n"); +@ + + +\subsection{Streams} +The zero stream\index{stream} is predefined for the main content. +@<default names@>= +typedef enum {@+ +zero_stream_no=0@+ +} stream_no_t; +#define MAX_STREAM_DEFAULT zero_stream_no +@ + +@<define stream defaults@>= +max_default[stream_kind]=MAX_STREAM_DEFAULT; +max_fixed[stream_kind]=zero_stream_no; +@ + + +\subsection{Page Templates} + +The zero page template\index{template} is a predefined, built-in page template. +@<default names@>= +typedef enum {@+ +zero_page_no=0@+ +} page_no_t; +#define MAX_PAGE_DEFAULT zero_page_no +@ + +@<define page defaults@>= +max_default[page_kind]=MAX_PAGE_DEFAULT; +max_fixed[page_kind]=zero_page_no; +@ + +\subsection{Page Ranges} + +The page\index{page range} range for the zero page template is +the entire content section. + +@<default names@>= +typedef enum {@+ +zero_range_no=0@+ +} range_no_t; +#define MAX_RANGE_DEFAULT zero_range_no +@ + +@<define range defaults@>= +max_default[range_kind]=MAX_RANGE_DEFAULT; +max_fixed[range_kind]=zero_range_no; +@ + + +\section{Content Section} +The content section\index{content section} is just a list of nodes. +Within the \.{shrink} program, +reading a node in long format will trigger writing the node in short format. +Similarly within the \.{stretch} program, reading a node +in short form will cause writing it in long format. As a consequence, +the main task of writing the content section in long format is accomplished +by calling |get_content| and writing it in the short format +is accomplished by parsing the |content_list|. + +%\readcode +\codesection{\redsymbol}{Reading the Long Format}\redindex{1}{6}{Content Section} +\label{content}% +@s CONTENT symbol +@<symbols@>= +%token CONTENT "content" +@ + +@<scanning rules@>= +::@=content@> :< return CONTENT; >: +@ + + +@<parsing rules@>= +content_section: START CONTENT { hput_content_start(); } @| content_list END @| + { hput_content_end(); hput_range_defs(); hput_label_defs(); }; +@ + +%\writecode +\codesection{\wrtsymbol}{Writing the Long Format}\wrtindex{1}{6}{Content Section} + +@<write functions@>= +void hwrite_content_section(void) +{ section_no=2; + hwritef("<content"); + hsort_ranges(); + hsort_labels(); + hget_content_section(); + hwritef("\n>\n"); +} +@ + +%\getcode +\codesection{\getsymbol}{Reading the Short Format}\getindex{1}{6}{Content Section} +@<get functions@>= +void hget_content_section() +{ DBG(DBGBASIC|DBGDIR,"Content\n"); + hget_section(2); + hwrite_range(); + hwrite_label(); + while(hpos<hend) + hget_content_node(); +} +@ + +%\putcode +\codesection{\putsymbol}{Writing the Short Format}\putindex{1}{6}{Content Section} +@<put functions@>= +void hput_content_start(void) +{ DBG(DBGDIR,"Content Section\n"); + section_no=2; + hpos0=hpos=hstart=dir[2].buffer; + hend=hstart+dir[2].bsize; + +} +void hput_content_end(void) +{ + dir[2].size=hpos-hstart; /* Updating the directory entry */ + DBG(DBGDIR,"End Content Section, size=0x%x\n", dir[2].size); +} +@ + + +\section{Processing the Command Line} +The following code explains the command line\index{command line} +parameters and options\index{option}\index{debugging}. +It tells us what to expect in the rest of this section. +{\def\SP{\hskip .5em} +@<explain usage@>= + fprintf(stderr, + "Usage: %s [options] filename%s\n",prog_name, in_ext);@/ + fprintf(stderr, + "Options:\n"@/ + "\t -o file\t specify an output file name\n"@/ + "\t -g \t assume global names for auxiliary files\n"@/ + "\t -l \t redirect stderr to a log file\n"@/ + "\t -u \t enable writing utf8 character codes\n"@/ + "\t -x \t enable writing hexadecimal character codes\n"@/ + "\t -c \t enable compression of section 1 and 2\n");@/ +#ifdef DEBUG +fprintf(stderr,"\t -d XXX \t hexadecimal value. OR together these values:\n");@/ +fprintf(stderr,"\t\t\t XX=%03X basic debugging\n", DBGBASIC);@/ +fprintf(stderr,"\t\t\t XX=%03X tag debugging\n", DBGTAGS);@/ +fprintf(stderr,"\t\t\t XX=%03X node debugging\n",DBGNODE);@/ +fprintf(stderr,"\t\t\t XX=%03X definition debugging\n", DBGDEF);@/ +fprintf(stderr,"\t\t\t XX=%03X directory debugging\n", DBGDIR);@/ +fprintf(stderr,"\t\t\t XX=%03X range debugging\n",DBGRANGE);@/ +fprintf(stderr,"\t\t\t XX=%03X float debugging\n", DBGFLOAT);@/ +fprintf(stderr,"\t\t\t XX=%03X compression debugging\n", DBGCOMPRESS);@/ +fprintf(stderr,"\t\t\t XX=%03X buffer debugging\n", DBGBUFFER);@/ +fprintf(stderr,"\t\t\t XX=%03X flex debugging\n", DBGFLEX);@/ +fprintf(stderr,"\t\t\t XX=%03X bison debugging\n", DBGBISON);@/ +fprintf(stderr,"\t\t\t XX=%03X TeX debugging\n", DBGTEX);@/ +fprintf(stderr,"\t\t\t XX=%03X Page debugging\n", DBGPAGE);@/ +fprintf(stderr,"\t\t\t XX=%03X Font debugging\n", DBGFONT);@/ +fprintf(stderr,"\t\t\t XX=%03X Render debugging\n", DBGRENDER);@/ +fprintf(stderr,"\t\t\t XX=%03X Label debugging\n", DBGLABEL);@/ +#endif +@ +} +We define constants for different debug flags. +@<debug constants@>= +#define DBGNONE 0x0 +#define DBGBASIC 0x1 +#define DBGTAGS 0x2 +#define DBGNODE 0x4 +#define DBGDEF 0x8 +#define DBGDIR 0x10 +#define DBGRANGE 0x20 +#define DBGFLOAT 0x40 +#define DBGCOMPRESS 0x80 +#define DBGBUFFER 0X100 +#define DBGFLEX 0x200 +#define DBGBISON 0x400 +#define DBGTEX 0x800 +#define DBGPAGE 0x1000 +#define DBGFONT 0x2000 +#define DBGRENDER 0x4000 +#define DBGLABEL 0x8000 +@ + +Next we define common variables that are +needed in all three programs defined here. + +@<common variables@>= +unsigned int debugflags=DBGNONE; +int option_utf8=false; +int option_hex=false; +int option_force=false; +int option_global=false; +int option_compress=false; +char *stem_name=NULL; +int stem_length=0; +@ +The variable |stem_name| contains the name of the input file +not including the extension. The space allocated for it +is large enough to append an extension with up to five characters. +It can be used with the extension {\tt .log} for the log file, +with {\tt .HINT} or {\tt .hnt} for the output file, +and with {\tt .abs} or {\tt .rel} when writing or reading the auxiliary sections. +The {\tt stretch} program will overwrite the |stem_name| +using the name of the output file if it is set with the {\tt -o} +option. + + +Next are the variables that are local in the |main| program. +@<local variables in |main|@>= +char *prog_name; +char *in_ext; +char *out_ext; +char *file_name=NULL; +int file_name_length=0; +int option_log=false; +@ + +Processing the command line looks for options and then sets the +input file name\index{file name}. + +@<process the command line@>= + debugflags=DBGBASIC; + prog_name=argv[0]; + if (argc < 2) goto explain_usage; + argv++; /* skip the program name */ + while (*argv!=NULL) + { if ((*argv)[0]=='-') + { char option=(*argv)[1]; + switch(option) + { default: goto explain_usage; + case 'o': argv++; + file_name_length=(int)strlen(*argv); + ALLOCATE(file_name,file_name_length+6,char); /*plus extension*/ + strcpy(file_name,*argv);@+ break; + case 'l': option_log=true; @+break; + case 'u': option_utf8=true;@+break; + case 'x': option_hex=true;@+break; + case 'f': option_force=true; @+break; + case 'g': option_global=true; @+break; + case 'c': option_compress=true; @+break; + case 'd': @/ + argv++; if (*argv==NULL) goto explain_usage; + debugflags=strtol(*argv,NULL,16); + break; + } + } + else /* the input file name */ + { int path_length=(int)strlen(*argv); + int ext_length=(int)strlen(in_ext); + ALLOCATE(hin_name,path_length+ext_length+1,char); + strcpy(hin_name,*argv); + if (path_length<ext_length + || strncmp(hin_name+path_length-ext_length,in_ext,ext_length)!=0) + { strcat(hin_name,in_ext); + path_length+=ext_length; + } + stem_length=path_length-ext_length; + ALLOCATE(stem_name,stem_length+6,char); + strncpy(stem_name,hin_name,stem_length); + stem_name[stem_length]=0; + if (*(argv+1)!=NULL) goto explain_usage; + } + argv++; + } + if (hin_name==NULL) goto explain_usage; +@ + +After the command line has been processed, three file streams need to be opened: +The input file |hin|\index{input file} and the output file |hout|\index{output file}. +Further we need a log file |hlog|\index{log file} if debugging is enabled. +For technical reasons, the scanner\index{scanning} generated by \.{flex} needs +an input file |yyin|\index{input file} which is set to |hin| +and an output file |yyout| (which is not used). + +@<common variables@>= +FILE *hin=NULL, *hout=NULL, *hlog=NULL; +@ + + +The log file is opened first because +this is the place where error messages\index{error message} +should go while the other files are opened. +It inherits its name from the input file name. + +@<open the log file@> = +#ifdef DEBUG + if (option_log) + { + strcat(stem_name,".log"); + hlog=freopen(stem_name,"w",stderr); + if (hlog==NULL) + { fprintf(stderr,"Unable to open logfile %s",stem_name); + hlog=stderr; + } + stem_name[stem_length]=0; + } + else + hlog=stderr; +#else + hlog=stderr; +#endif +@ + +Once we have established logging, we can try to open the other files. +@<open the input file@>= + hin=fopen(hin_name,"rb"); + if (hin==NULL) QUIT("Unable to open input file %s",hin_name); +@ + +@<open the output file@>= + if (file_name!=NULL) + { int ext_length=(int)strlen(out_ext); + if (file_name_length<=ext_length + || strncmp(file_name+file_name_length-ext_length,out_ext,ext_length)!=0) + { strcat(file_name,out_ext); file_name_length+=ext_length; } + } + else + { file_name_length=stem_length+(int)strlen(out_ext); + ALLOCATE(file_name,file_name_length+1,char); + strcpy(file_name,stem_name);@+ + strcpy(file_name+stem_length,out_ext); + } + @<make sure the path in |file_name| exists@>@; + hout=fopen(file_name,"wb"); + if (hout==NULL) QUIT("Unable to open output file %s",file_name); +@ + +The {\tt stretch} program will replace the |stem_name| using the stem of the +output file. +@<determine the |stem_name| from the output |file_name|@>= +stem_length=file_name_length-(int)strlen(out_ext); +ALLOCATE(stem_name,stem_length+6,char); +strncpy(stem_name,file_name,stem_length); +stem_name[stem_length]=0; +@ + +At the very end, we will close the files again. +@<close the input file@>= +if (hin_name!=NULL) free(hin_name); +if (hin!=NULL) fclose(hin); +@ +@<close the output file@>= +if (file_name!=NULL) free(file_name); +if (hout!=NULL) fclose(hout); +@ +@<close the log file@>= +if (hlog!=NULL) fclose(hlog); +if (stem_name!=NULL) free(stem_name); +@ + + + +\section{Error Handling and Debugging}\label{error_section} +There is no good program without good error handling\index{error message}\index{debugging}. +To print messages\index{message} or indicate errors, I define the following macros: +\index{MESSAGE+\.{MESSAGE}}\index{QUIT+\.{QUIT}} + +@(error.h@>= +#ifndef _ERROR_H +#define _ERROR_H +#include <stdlib.h> +#include <stdio.h> +extern FILE *hlog; +extern uint8_t *hpos, *hstart; +#define @[LOG(...)@] @[(fprintf(hlog,__VA_ARGS__),fflush(hlog))@] +#define @[MESSAGE(...)@] @[(fprintf(hlog,__VA_ARGS__),fflush(hlog))@] +#define @[QUIT(...)@] (MESSAGE("ERROR: " __VA_ARGS__),fprintf(hlog,"\n"),exit(1)) + +#endif +@ + + +The amount of debugging\index{debugging} depends on the debugging flags. +For portability, we first define the output specifier for expressions of type |size_t|. +\index{DBG+\.{DBG}}\index{SIZE F+\.{SIZE\_F}}\index{DBGTAG+\.{DBGTAG}} +\index{RNG+\.{RNG}}\index{TAGERR+\.{TAGERR}} +@<debug macros@>= +#ifdef WIN32 +#define SIZE_F "0x%x" +#else +#define SIZE_F "0x%zx" +#endif +#ifdef DEBUG +#define @[DBG(FLAGS,...)@] ((debugflags & (FLAGS))?LOG(__VA_ARGS__):0) +#else +#define @[DBG(FLAGS,...)@] 0 +#endif +#define @[DBGTAG(A,P)@] @[DBG(DBGTAGS,@["tag [%s,%d] at " SIZE_F "\n"@],@|NAME(A),INFO(A),(P)-hstart)@] + +#define @[RNG(S,N,A,Z)@] @/\ + if ((int)(N)<(int)(A)||(int)(N)>(int)(Z)) QUIT(S@, " %d out of range [%d - %d]",N,A,Z) + +#define @[TAGERR(A)@] @[QUIT(@["Unknown tag [%s,%d] at " SIZE_F "\n"@],NAME(A),INFO(A),hpos-hstart)@] +@ + +The \.{bison} generated parser will need a function |yyerror| for +error reporting. We can define it now: + +@<parsing functions@>= +extern int yylineno; +int yyerror(const char *msg) +{ QUIT(" in line %d %s",yylineno,msg); + return 0; +} +@ + +To enable the generation of debugging code \.{bison} needs also the following: +@<enable bison debugging@>= +#ifdef DEBUG +#define YYDEBUG 1 +extern int yydebug; +#else +#define YYDEBUG 0 +#endif +@ + + +\appendix + +\section{Traversing Short Format Files}\label{fastforward} +For applications like searching or repositioning a file after reloading +a possibly changed version of a file, it is useful to have a fast way +of getting from one content node to the next. +For quite some nodes, it is possible to know the size of the +node from the tag. So the fastest way to get to the next node +is looking up the node size in a table. + +Other important nodes, for example hbox, vbox, or par nodes, end with a +list node and it is possible to know the size of the node up to the final +list. With that knowledge it is possible to skip the initial +part of the node, then skip the list, and finally skip the tag byte. +The size of the initial part can be stored in the same node size table +using negated values. What works for lists, +of course, will work for other kinds of nodes as well. +So we use the lowest two bits of the values in the size table +to store the number of embedded nodes that follow after the initial part. + +For list nodes neither of these methods works and these nodes can be marked +with a zero entry in the node size table. + +This leads to the following code for a ``fast forward'' function +for |hpos|: + +@<shared skip functions@>= +uint32_t hff_list_pos=0, hff_list_size=0; +uint8_t hff_tag; +void hff_hpos(void) +{ signed char i,k; + hff_tag=*hpos;@+ + DBGTAG(hff_tag,hpos); + i= hnode_size[hff_tag]; + if (i>0) {hpos=hpos+i; @+return;@+ } + else if (i<0) + { k=1+(i&0x3);@+ i=i>>2; + hpos=hpos-i; /* skip initial part */ + while (k>0) + { hff_hpos(); @+k--; @+} /* skip trailing nodes */ + hpos++;/* skip end byte */ + return; + } + else if (hff_tag <=TAG(param_kind,5)) + @<advance |hpos| over a list@>@; + TAGERR(hff_tag); +} +@ + + +We will put the |hnode_size| variable into the {\tt hformat.c} file +using the following function. We add some comments and +split negative values into their components, to make the result more +readable. + +@<print the |hnode_size| variable@>= + printf("signed char hnode_size[0x100]= {\n"); + for (i=0; i<=0xff; i++)@/ + { signed char s = hnode_size[i]; + if (s>=0) printf("%d",s); else printf("-4*%d+%d",-(s>>2),s&3); + if (i<0xff) printf(","); else printf("};"); + if ((i&0x7)==0x7) printf(" /* %s */\n", content_name[KIND(i)]); + } + printf("\n\n"); +@ + +\subsection{Lists}\index{list}\index{text}\index{parameters} +List don't follow the usual schema of nodes. They have a variable size +that is stored in the node. We keep position and size in global variables +so that the list that ends a node can be conveniently located. + +@<advance |hpos| over a list@>= +switch (INFO(hff_tag)){ +case 1: hff_list_pos=hpos-hstart+1;hff_list_size=0; hpos=hpos+2;@+ return; +case 2: hpos++;@+ hff_list_size=HGET8;@+ hff_list_pos=hpos-hstart+1; hpos=hpos+1+hff_list_size+1+1+1;@+ return; +case 3: hpos++;@+ HGET16(hff_list_size);@+hff_list_pos=hpos-hstart+1; hpos=hpos+1+hff_list_size+1+2+1;@+ return; +case 4: hpos++;@+ HGET24(hff_list_size);@+hff_list_pos=hpos-hstart+1; hpos=hpos+1+hff_list_size+1+3+1;@+ return; +case 5: hpos++;@+ HGET32(hff_list_size);@+hff_list_pos=hpos-hstart+1; hpos=hpos+1+hff_list_size+1+4+1;@+ return; +} +@ + +Now let's consider the different kinds of nodes. + +\subsection{Glyphs}\index{glyph} +We start with the glyph nodes. All glyph nodes +have a start and an end tag, one byte for the font, +and depending on the info from 1 to 4 bytes for the character code. + +@<initialize the |hnode_size| array@>= +hnode_size[TAG(glyph_kind,1)] = 1+1+1+1; +hnode_size[TAG(glyph_kind,2)] = 1+1+2+1; +hnode_size[TAG(glyph_kind,3)] = 1+1+3+1; +hnode_size[TAG(glyph_kind,4)] = 1+1+4+1; +@ + +\subsection{Penalties}\index{penalty} +Penalty nodes either contain a one byte reference, a one byte number, or a two byte number. + +@<initialize the |hnode_size| array@>= +hnode_size[TAG(penalty_kind,0)] = 1+1+1; +hnode_size[TAG(penalty_kind,1)] = 1+1+1; +hnode_size[TAG(penalty_kind,2)] = 1+2+1; +@ + +\subsection{Kerns}\index{kern} +Kern nodes can contain a reference (either to a dimension or an extended dimension) +a dimension, or an extended dimension node. + +@<initialize the |hnode_size| array@>= +hnode_size[TAG(kern_kind,b000)] = 1+1+1; +hnode_size[TAG(kern_kind,b001)] = 1+1+1; +hnode_size[TAG(kern_kind,b010)] = 1+4+1; +hnode_size[TAG(kern_kind,b011)] = I_T(1,1); +hnode_size[TAG(kern_kind,b100)] = 1+1+1; +hnode_size[TAG(kern_kind,b101)] = 1+1+1; +hnode_size[TAG(kern_kind,b110)] = 1+4+1; +hnode_size[TAG(kern_kind,b111)] = I_T(1,1); +@ + +For the two cases where a kern node contains an extended dimension, +we use the following macro to combine the size of the initial part +with the number of trailing nodes: +@<skip macros@>= +#define @[I_T(I,T)@] (((-(I))<<2)|((T)-1)) +@ + +\subsection{Extended Dimensions}\index{extended dimension} +Extended dimensions contain either one two or three 4 byte values depending +on the info bits. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(xdimen_kind,b100)] = 1+4+1; +hnode_size[TAG(xdimen_kind,b010)] = 1+4+1; +hnode_size[TAG(xdimen_kind,b001)] = 1+4+1; +hnode_size[TAG(xdimen_kind,b110)] = 1+4+4+1; +hnode_size[TAG(xdimen_kind,b101)] = 1+4+4+1; +hnode_size[TAG(xdimen_kind,b011)] = 1+4+4+1; +hnode_size[TAG(xdimen_kind,b111)] = 1+4+4+4+1; +@ + +\subsection{Language}\index{language} +Language nodes either code the language in the info value or they contain +a reference byte. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(language_kind,b000)] = 1+1+1; +hnode_size[TAG(language_kind,1)] = 1+1; +hnode_size[TAG(language_kind,2)] = 1+1; +hnode_size[TAG(language_kind,3)] = 1+1; +hnode_size[TAG(language_kind,4)] = 1+1; +hnode_size[TAG(language_kind,5)] = 1+1; +hnode_size[TAG(language_kind,6)] = 1+1; +hnode_size[TAG(language_kind,7)] = 1+1; +@ + +\subsection{Rules}\index{rule} +Rules usually contain a reference, otherwise +they contain either one, two, or three 4 byte values depending +on the info bits. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(rule_kind,b000)] = 1+1+1; +hnode_size[TAG(rule_kind,b100)] = 1+4+1; +hnode_size[TAG(rule_kind,b010)] = 1+4+1; +hnode_size[TAG(rule_kind,b001)] = 1+4+1; +hnode_size[TAG(rule_kind,b110)] = 1+4+4+1; +hnode_size[TAG(rule_kind,b101)] = 1+4+4+1; +hnode_size[TAG(rule_kind,b011)] = 1+4+4+1; +hnode_size[TAG(rule_kind,b111)] = 1+4+4+4+1; +@ + +\subsection{Glue}\index{glue} +Glues usually contain a reference or +they contain either one two or three 4 byte values depending +on the info bits, and possibly even an extended dimension node followed +by two 4 byte values. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(glue_kind,b000)] = 1+1+1; +hnode_size[TAG(glue_kind,b100)] = 1+4+1; +hnode_size[TAG(glue_kind,b010)] = 1+4+1; +hnode_size[TAG(glue_kind,b001)] = 1+4+1; +hnode_size[TAG(glue_kind,b110)] = 1+4+4+1; +hnode_size[TAG(glue_kind,b101)] = 1+4+4+1; +hnode_size[TAG(glue_kind,b011)] = 1+4+4+1; +hnode_size[TAG(glue_kind,b111)] = I_T(1+4+4,1); +@ + + +\subsection{Boxes}\index{box} +The layout of boxes is quite complex and explained in section~\secref{boxnodes}. +All boxes contain height and width, some contain a depth, some a shift amount, +and some a glue setting together with glue sign and glue order. +The last item in a box is a node list. + +@<initialize the |hnode_size| array@>= +hnode_size[TAG(hbox_kind,b000)] = I_T(1+4+4,1); /* tag, height, width*/ +hnode_size[TAG(hbox_kind,b001)] = I_T(1+4+4+4,1); /* and depth */ +hnode_size[TAG(hbox_kind,b010)] = I_T(1+4+4+4,1); /* or shift */ +hnode_size[TAG(hbox_kind,b011)] = I_T(1+4+4+4+4,1); /* or both */ +hnode_size[TAG(hbox_kind,b100)] = I_T(1+4+4+5,1); /* and glue setting*/ +hnode_size[TAG(hbox_kind,b101)] = I_T(1+4+4+4+5,1); /* and depth */ +hnode_size[TAG(hbox_kind,b110)] = I_T(1+4+4+4+5,1); /* or shift */ +hnode_size[TAG(hbox_kind,b111)] = I_T(1+4+4+4+4+5,1); /*or both */ +hnode_size[TAG(vbox_kind,b000)] = I_T(1+4+4,1); /* same for vbox*/ +hnode_size[TAG(vbox_kind,b001)] = I_T(1+4+4+4,1); +hnode_size[TAG(vbox_kind,b010)] = I_T(1+4+4+4,1); +hnode_size[TAG(vbox_kind,b011)] = I_T(1+4+4+4+4,1); +hnode_size[TAG(vbox_kind,b100)] = I_T(1+4+4+5,1); +hnode_size[TAG(vbox_kind,b101)] = I_T(1+4+4+4+5,1); +hnode_size[TAG(vbox_kind,b110)] = I_T(1+4+4+4+5,1); +hnode_size[TAG(vbox_kind,b111)] = I_T(1+4+4+4+4+5,1); +@ + +\subsection{Extended Boxes}\index{extended box} +Extended boxes start with height, width, depth, stretch, or shrink components. +Then follows an extended dimension either as a reference or a node. +The node ends with a list. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(hset_kind,b000)] = I_T(1+4+4+4+4+1,1); +hnode_size[TAG(hset_kind,b001)] = I_T(1+4+4+4+4+4+1,1); +hnode_size[TAG(hset_kind,b010)] = I_T(1+4+4+4+4+4+1,1); +hnode_size[TAG(hset_kind,b011)] = I_T(1+4+4+4+4+4+4+1,1); +hnode_size[TAG(vset_kind,b000)] = I_T(1+4+4+4+4+1,1); +hnode_size[TAG(vset_kind,b001)] = I_T(1+4+4+4+4+4+1,1); +hnode_size[TAG(vset_kind,b010)] = I_T(1+4+4+4+4+4+1,1); +hnode_size[TAG(vset_kind,b011)] = I_T(1+4+4+4+4+4+4+1,1); + +hnode_size[TAG(hset_kind,b100)] = I_T(1+4+4+4+4,2); +hnode_size[TAG(hset_kind,b101)] = I_T(1+4+4+4+4+4,2); +hnode_size[TAG(hset_kind,b110)] = I_T(1+4+4+4+4+4,2); +hnode_size[TAG(hset_kind,b111)] = I_T(1+4+4+4+4+4+4,2); +hnode_size[TAG(vset_kind,b100)] = I_T(1+4+4+4+4,2); +hnode_size[TAG(vset_kind,b101)] = I_T(1+4+4+4+4+4,2); +hnode_size[TAG(vset_kind,b110)] = I_T(1+4+4+4+4+4,2); +hnode_size[TAG(vset_kind,b111)] = I_T(1+4+4+4+4+4+4,2); +@ + +The hpack and vpack nodes start with a shift amount and in case of vpack a depth. +Then again an extended dimension and a list. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(hpack_kind,b000)] = I_T(1+1,1); +hnode_size[TAG(hpack_kind,b001)] = I_T(1+1,1); +hnode_size[TAG(hpack_kind,b010)] = I_T(1+4+1,1); +hnode_size[TAG(hpack_kind,b011)] = I_T(1+4+1,1); +hnode_size[TAG(vpack_kind,b000)] = I_T(1+4+1,1); +hnode_size[TAG(vpack_kind,b001)] = I_T(1+4+1,1); +hnode_size[TAG(vpack_kind,b010)] = I_T(1+4+4+1,1); +hnode_size[TAG(vpack_kind,b011)] = I_T(1+4+4+1,1); + +hnode_size[TAG(hpack_kind,b100)] = I_T(1,2); +hnode_size[TAG(hpack_kind,b101)] = I_T(1,2); +hnode_size[TAG(hpack_kind,b110)] = I_T(1+4,2); +hnode_size[TAG(hpack_kind,b111)] = I_T(1+4,2); +hnode_size[TAG(vpack_kind,b100)] = I_T(1+4,2); +hnode_size[TAG(vpack_kind,b101)] = I_T(1+4,2); +hnode_size[TAG(vpack_kind,b110)] = I_T(1+4+4,2); +hnode_size[TAG(vpack_kind,b111)] = I_T(1+4+4,2); +@ + +\subsection{Leaders}\index{leaders} +Most leader nodes will use a reference. +Otherwise they contain a glue node followed by a box or rule node. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(leaders_kind,b000)] = 1+1+1; +hnode_size[TAG(leaders_kind,1)] = I_T(1,1); +hnode_size[TAG(leaders_kind,2)] = I_T(1,1); +hnode_size[TAG(leaders_kind,3)] = I_T(1,1); +hnode_size[TAG(leaders_kind,b100|1)] = I_T(1,2); +hnode_size[TAG(leaders_kind,b100|2)] = I_T(1,2); +hnode_size[TAG(leaders_kind,b100|3)] = I_T(1,2); +@ + +\subsection{Baseline Skips}\index{baseline skip} +Here we expect either a reference or two optional glue nodes followed by an optional dimension. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(baseline_kind,b000)] = 1+1+1; +hnode_size[TAG(baseline_kind,b001)] = 1+4+1; +hnode_size[TAG(baseline_kind,b010)] = I_T(1,1); +hnode_size[TAG(baseline_kind,b100)] = I_T(1,1); +hnode_size[TAG(baseline_kind,b110)] = I_T(1,2); + +hnode_size[TAG(baseline_kind,b011)] = I_T(1+4,1); +hnode_size[TAG(baseline_kind,b101)] = I_T(1+4,1); +hnode_size[TAG(baseline_kind,b111)] = I_T(1+4,2); +@ + + +\subsection{Ligatures}\index{ligature} +As usual a reference is possible, otherwise the font is followed by character bytes +as given by the info. Only if the info value is 7, the number of character bytes +is stored separately. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(ligature_kind,b000)] = 1+1+1; +hnode_size[TAG(ligature_kind,1)] = 1+1+1+1; +hnode_size[TAG(ligature_kind,2)] = 1+1+2+1; +hnode_size[TAG(ligature_kind,3)] = 1+1+3+1; +hnode_size[TAG(ligature_kind,4)] = 1+1+4+1; +hnode_size[TAG(ligature_kind,5)] = 1+1+5+1; +hnode_size[TAG(ligature_kind,6)] = 1+1+6+1; +hnode_size[TAG(ligature_kind,7)] = I_T(1+1,1); +@ + +\subsection{Discretionary breaks}\index{discretionary break} +The simple cases here are references, discretionary breaks +with empty pre- and post-list, or with a zero line skip limit +Otherwise one or two lists are followed by an optional replace count. + +@<initialize the |hnode_size| array@>= +hnode_size[TAG(disc_kind,b000)] = 1+1+1; +hnode_size[TAG(disc_kind,b010)] = I_T(1,1); +hnode_size[TAG(disc_kind,b011)] = I_T(1,2); +hnode_size[TAG(disc_kind,b100)] = 1+1+1; +hnode_size[TAG(disc_kind,b110)] = I_T(1+1,1); +hnode_size[TAG(disc_kind,b111)] = I_T(1+1,2); +@ + +\subsection{Paragraphs}\index{paragraph} +Paragraph nodes contain an extended dimension, an parameter list and a list. +The first two can be given as a reference. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(par_kind,b000)] = I_T(1+1+1,1); +hnode_size[TAG(par_kind,b010)] = I_T(1+1,2); +hnode_size[TAG(par_kind,b110)] = I_T(1,3); +hnode_size[TAG(par_kind,b100)] = I_T(1+1,2); +@ + +\subsection{Mathematics}\index{mathematics}\index{displayed formula} +Displayed math needs a parameter list, either as list or as reference +followed by an optional left or right equation number and a list. +Text math is simpler: the only information is in the info value. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(math_kind,b000)] = I_T(1+1,1); +hnode_size[TAG(math_kind,b001)] = I_T(1+1,2); +hnode_size[TAG(math_kind,b010)] = I_T(1+1,2); +hnode_size[TAG(math_kind,b100)] = I_T(1,2); +hnode_size[TAG(math_kind,b101)] = I_T(1,3); +hnode_size[TAG(math_kind,b110)] = I_T(1,3); +hnode_size[TAG(math_kind,b111)] = 1+1; +hnode_size[TAG(math_kind,b011)] = 1+1; +@ + +\subsection{Adjustments}\index{adjustment} +@<initialize the |hnode_size| array@>= +hnode_size[TAG(adjust_kind,1)] = I_T(1,1); +@ + +\subsection{Tables}\index{alignment} +Tables have an extended dimension either as a node or as a reference followed +by two lists. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(table_kind,b000)] = I_T(1+1,2); +hnode_size[TAG(table_kind,b001)] = I_T(1+1,2); +hnode_size[TAG(table_kind,b010)] = I_T(1+1,2); +hnode_size[TAG(table_kind,b011)] = I_T(1+1,2); +hnode_size[TAG(table_kind,b100)] = I_T(1,3); +hnode_size[TAG(table_kind,b101)] = I_T(1,3); +hnode_size[TAG(table_kind,b110)] = I_T(1,3); +hnode_size[TAG(table_kind,b111)] = I_T(1,3); +@ +Outer item nodes are lists of inner item nodes, inner item nodes are box nodes +followed by an optional span count. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(item_kind,b000)] = I_T(1,1); /* outer */ +hnode_size[TAG(item_kind,1)] = I_T(1,1); /* inner */ +hnode_size[TAG(item_kind,2)] = I_T(1,1); +hnode_size[TAG(item_kind,3)] = I_T(1,1); +hnode_size[TAG(item_kind,4)] = I_T(1,1); +hnode_size[TAG(item_kind,5)] = I_T(1,1); +hnode_size[TAG(item_kind,6)] = I_T(1,1); +hnode_size[TAG(item_kind,6)] = I_T(2,1); +@ + +\subsection{Images}\index{image} +If not given by a reference, images contain a section reference and optional dimensions, stretch, and shrink. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(image_kind,b000)] = 1+1+1; +hnode_size[TAG(image_kind,b100)] = 1+2+1; +hnode_size[TAG(image_kind,b101)] = 1+2+4+4+1; +hnode_size[TAG(image_kind,b110)] = 1+2+4+4+1; +hnode_size[TAG(image_kind,b111)] = 1+2+4+4+4+4+1; +@ + +\subsection{Links}\index{link} +Links contain either a 2 byte or a 1 byte reference. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(link_kind,b000)] = 1+1+1; +hnode_size[TAG(link_kind,b001)] = 1+2+1; +hnode_size[TAG(link_kind,b010)] = 1+1+1; +hnode_size[TAG(link_kind,b011)] = 1+2+1; +@ + +\subsection{Stream Nodes}\index{stream} +After the stream reference follows a parameter list, either as reference +or as a list, and then a content list. +@<initialize the |hnode_size| array@>= +hnode_size[TAG(stream_kind,b000)] = I_T(1+1+1,1); +hnode_size[TAG(stream_kind,b010)] = I_T(1+1,2); +@ + + +\section{Reading Short Format Files Backwards} +This section is not really part of the file format definition, but it +illustrates an important property of the content section in short +format files: it can be read in both directions. This is important +because we want to be able to start at an arbitrary point in the +content and from there move pagewise backward. + +The program {\tt skip}\index{skip+{\tt skip}} described in this +section does just that. As wee see in appendix~\secref{skip}, its +|main| program is almost the same as the |main| program of the program +{\tt stretch} in appendix~\secref{stretchmain}. +The major difference is the removal of an output file +and the replacement of the call to |hwrite_content_section| by +a call to |hteg_content_section|. + +@<skip functions@>= +static void hteg_content_section(void) +{ hget_section(2); + hpos=hend; + while(hpos>hstart) + hteg_content_node(); +} +@ + +The functions |hteg_content_section| and |hteg_content_node| above are +reverse versions of the functions |hget_content_section| and +|hget_content_node|. Many such ``reverse functions'' will follow now +and we will consistently use the same naming scheme: replacing +``{\it get\/}`` by ``{\it teg\/}'' or ``{\tt GET}'' by ``{\tt TEG}''. +The {\tt skip} program does not do much input +checking; it will just extract enough information from a content node +to skip a node and ``advance'' or better ``retreat'' to the previous +node. + +@<skip functions@>= +static void hteg_content_node(void) +{ @<skip the end byte |z|@>@; + hteg_content(z); + @<skip and check the start byte |a|@>@; +} + +static void hteg_content(uint8_t z) +{@+ switch (z)@/ + { + @<cases to skip content@>@;@t\1@>@/ + default: + TAGERR(z); + break;@t\2@>@/ + } +} +@ + +The code to skip the end\index{end byte} byte |z| and to check the start\index{start byte} byte |a| is used repeatedly. + +@<skip the end byte |z|@>= + uint8_t a,z; /* the start and the end byte*/ + uint32_t node_pos=hpos-hstart; + if (hpos<=hstart) return; + HTEGTAG(z); +@ + +@<skip and check the start byte |a|@>= + HTEGTAG(a); + if (a!=z) QUIT(@["Tag mismatch [%s,%d]!=[%s,%d] at " SIZE_F " to 0x%x\n"@],@|NAME(a),INFO(a),NAME(z),INFO(z),@| + hpos-hstart,node_pos-1); +@ + +We replace the ``{\tt GET}'' macros by the following ``{\tt TEG}'' macros: + +@<shared get macros@>= +#define @[HBACK(X)@] @[((hpos-(X)<hstart)?(QUIT("HTEG underflow\n"),NULL):(hpos-=(X)))@] + +#define @[HTEG8@] (HBACK(1),hpos[0]) +#define @[HTEG16(X)@] (HBACK(2),(X)=(hpos[0]<<8)+hpos[1]) +#define @[HTEG24(X)@] (HBACK(3),(X)=(hpos[0]<<16)+(hpos[1]<<8)+hpos[2]) +#define @[HTEG32(X)@] (HBACK(4),(X)=(hpos[0]<<24)+(hpos[1]<<16)+(hpos[2]<<8)+hpos[3]) +#define @[HTEGTAG(X)@] @[X=HTEG8,DBGTAG(X,hpos)@] +@ + +Now we review step by step the different kinds of nodes. +\subsection{Floating Point Numbers}\index{floating point number} +\noindent +@<shared skip functions@>= +float32_t hteg_float32(void) +{ union {@+float32_t d; @+ uint32_t bits; @+} u; + HTEG32(u.bits); + return u.d; +} +@ + + +\subsection{Extended Dimensions}\index{extended dimension} +\noindent +@<skip macros@>= +#define @[HTEG_XDIMEN(I,X)@] \ + if((I)&b001) HTEG32((X).v); \ + if((I)&b010) HTEG32((X).h);\ + if((I)&b100) HTEG32((X).w); +@ + +@<skip functions@>= +static void hteg_xdimen_node(xdimen_t *x) +{ @<skip the end byte |z|@>@; + switch(z) + { +#if 0 +/* currently the info value 0 is not supported */ +case TAG(xdimen_kind,b000): /* see section~\secref{reference} */ + {uint8_t n;@+ n=HTEG8;} @+ break; +#endif + case TAG(xdimen_kind,b001): HTEG_XDIMEN(b001,*x);@+break; + case TAG(xdimen_kind,b010): HTEG_XDIMEN(b010,*x);@+break; + case TAG(xdimen_kind,b011): HTEG_XDIMEN(b011,*x);@+break; + case TAG(xdimen_kind,b100): HTEG_XDIMEN(b100,*x);@+break; + case TAG(xdimen_kind,b101): HTEG_XDIMEN(b101,*x);@+break; + case TAG(xdimen_kind,b110): HTEG_XDIMEN(b110,*x);@+break; + case TAG(xdimen_kind,b111): HTEG_XDIMEN(b111,*x);@+break; + default: + QUIT("Extent expected at 0x%x got %s",node_pos,NAME(z)); @+ break; + } +@<skip and check the start byte |a|@>@; +} +@ + + +\subsection{Stretch and Shrink}\index{stretchability}\index{shrinkability} +\noindent +@<skip macros@>= +#define @[HTEG_STRETCH(S)@] { stch_t st; @+ HTEG32(st.u);@+ S.o=st.u&3;@+ st.u&=~3;@+ S.f=st.f; @+} +@ + +\subsection{Glyphs}\index{glyph} +\noindent +@<skip macros@>= +#define HTEG_GLYPH(I,G) \ + (G).f=HTEG8; \ + if (I==1) (G).c=HTEG8;\ + else if (I==2) HTEG16((G).c);\ + else if (I==3) HTEG24((G).c);\ + else if (I==4) HTEG32((G).c); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(glyph_kind,1): @+{@+glyph_t g;@+ HTEG_GLYPH(1,g);@+}@+break; +case TAG(glyph_kind,2): @+{@+glyph_t g;@+ HTEG_GLYPH(2,g);@+}@+break; +case TAG(glyph_kind,3): @+{@+glyph_t g;@+ HTEG_GLYPH(3,g);@+}@+break; +case TAG(glyph_kind,4): @+{@+glyph_t g;@+ HTEG_GLYPH(4,g);@+}@+break; +@ + + +\subsection{Penalties}\index{penalty} +\noindent +@<skip macros@>= +#define @[HTEG_PENALTY(I,P)@] \ +if (I==1) {int8_t n; @+n=HTEG8; @+P=n;@+ } \ +else {int16_t n;@+ HTEG16(n); @+ P=n; @+}\ +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(penalty_kind,1): @+{int32_t p;@+ HTEG_PENALTY(1,p);@+} @+break; +case TAG(penalty_kind,2): @+{int32_t p;@+ HTEG_PENALTY(2,p);@+} @+break; +@ + + +\subsection{Kerns}\index{kern} +\noindent +@<skip macros@>= +#define @[HTEG_KERN(I,X)@] @[if (((I)&b011)==2) HTEG32(X.w); else if (((I)&b011)==3) hteg_xdimen_node(&(X))@] +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(kern_kind,b010): @+ {@+xdimen_t x; @+HTEG_KERN(b010,x);@+ } @+break; +case TAG(kern_kind,b011): @+ {@+xdimen_t x; @+HTEG_KERN(b011,x);@+ } @+break; +case TAG(kern_kind,b110): @+ {@+xdimen_t x; @+HTEG_KERN(b110,x);@+ } @+break; +case TAG(kern_kind,b111): @+ {@+xdimen_t x; @+HTEG_KERN(b111,x);@+ } @+break; +@ + +\subsection{Language}\index{language} +\noindent +@<cases to skip content@>= +@t\kern1em@>case TAG(language_kind,1): +case TAG(language_kind,2): +case TAG(language_kind,3): +case TAG(language_kind,4): +case TAG(language_kind,5): +case TAG(language_kind,6): +case TAG(language_kind,7):@+break; +@ + +\subsection{Rules}\index{rule} +\noindent +@<skip macros@>= +#define @[HTEG_RULE(I,R)@]@/\ +if ((I)&b001) HTEG32((R).w); @+else (R).w=RUNNING_DIMEN;\ +if ((I)&b010) HTEG32((R).d); @+else (R).d=RUNNING_DIMEN;\ +if ((I)&b100) HTEG32((R).h); @+else (R).h=RUNNING_DIMEN; +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(rule_kind,b011): @+ {rule_t r;@+ HTEG_RULE(b011,r);@+ }@+ break; +case TAG(rule_kind,b101): @+ {rule_t r;@+ HTEG_RULE(b101,r);@+ }@+ break; +case TAG(rule_kind,b001): @+ {rule_t r;@+ HTEG_RULE(b001,r);@+ }@+ break; +case TAG(rule_kind,b110): @+ {rule_t r;@+ HTEG_RULE(b110,r);@+ }@+ break; +case TAG(rule_kind,b111): @+ {rule_t r;@+ HTEG_RULE(b111,r);@+ }@+ break; +@ + +@<skip functions@>= +static void hteg_rule_node(void) +{ @<skip the end byte |z|@>@; + if (KIND(z)==rule_kind) { @+rule_t r; @+HTEG_RULE(INFO(z),r); @+} + else + QUIT("Rule expected at 0x%x got %s",node_pos,NAME(z)); + @<skip and check the start byte |a|@>@; +} +@ +\subsection{Glue}\index{glue} +\noindent +@<skip macros@>= +#define @[HTEG_GLUE(I,G)@] @/\ + if(I==b111) hteg_xdimen_node(&((G).w)); else (G).w.h=(G).w.v=0.0;\ + if((I)&b001) HTEG_STRETCH((G).m) @+else (G).m.f=0.0, (G).m.o=0; \ + if((I)&b010) HTEG_STRETCH((G).p) @+else (G).p.f=0.0, (G).p.o=0;\ + if((I)!=b111) { @+if ((I)&b100) HTEG32((G).w.w);@+ else (G).w.w=0;@+ } +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(glue_kind,b001): @+{ glue_t g;@+ HTEG_GLUE(b001,g);@+}@+break; +case TAG(glue_kind,b010): @+{ glue_t g;@+ HTEG_GLUE(b010,g);@+}@+break; +case TAG(glue_kind,b011): @+{ glue_t g;@+ HTEG_GLUE(b011,g);@+}@+break; +case TAG(glue_kind,b100): @+{ glue_t g;@+ HTEG_GLUE(b100,g);@+}@+break; +case TAG(glue_kind,b101): @+{ glue_t g;@+ HTEG_GLUE(b101,g);@+}@+break; +case TAG(glue_kind,b110): @+{ glue_t g;@+ HTEG_GLUE(b110,g);@+}@+break; +case TAG(glue_kind,b111): @+{ glue_t g;@+ HTEG_GLUE(b111,g);@+}@+break; +@ + +@<skip functions@>= +static void hteg_glue_node(void) +{ @<skip the end byte |z|@>@; + if (INFO(z)==b000) HTEG_REF(glue_kind); + else + { @+glue_t g; @+HTEG_GLUE(INFO(z),g);@+} + @<skip and check the start byte |a|@>@; +} +@ + +\subsection{Boxes}\index{box} +\noindent +@<skip macros@>= +#define @[HTEG_BOX(I,B)@] \ +hteg_list(&(B.l));\ +if ((I)&b100) @/{ B.s=HTEG8; @+ B.r=hteg_float32();@+ B.o=B.s&0xF; @+B.s=B.s>>4;@+ }\ +else { B.r=0.0;@+ B.o=B.s=0;@+ }\ +if ((I)&b010) HTEG32(B.a); @+else B.a=0;\ +HTEG32(B.w);\ +if ((I)&b001) HTEG32(B.d); @+ else B.d=0;\ +HTEG32(B.h);\ +@ + +@<cases to skip content@>= +@t\1\kern1em@> case TAG(hbox_kind,b000): @+{box_t b; @+HTEG_BOX(b000,b);@+} @+ break; +case TAG(hbox_kind,b001): @+{box_t b; @+HTEG_BOX(b001,b);@+} @+ break; +case TAG(hbox_kind,b010): @+{box_t b; @+HTEG_BOX(b010,b);@+} @+ break; +case TAG(hbox_kind,b011): @+{box_t b; @+HTEG_BOX(b011,b);@+} @+ break; +case TAG(hbox_kind,b100): @+{box_t b; @+HTEG_BOX(b100,b);@+} @+ break; +case TAG(hbox_kind,b101): @+{box_t b; @+HTEG_BOX(b101,b);@+} @+ break; +case TAG(hbox_kind,b110): @+{box_t b; @+HTEG_BOX(b110,b);@+} @+ break; +case TAG(hbox_kind,b111): @+{box_t b; @+HTEG_BOX(b111,b);@+} @+ break; +case TAG(vbox_kind,b000): @+{box_t b; @+HTEG_BOX(b000,b);@+} @+ break; +case TAG(vbox_kind,b001): @+{box_t b; @+HTEG_BOX(b001,b);@+} @+ break; +case TAG(vbox_kind,b010): @+{box_t b; @+HTEG_BOX(b010,b);@+} @+ break; +case TAG(vbox_kind,b011): @+{box_t b; @+HTEG_BOX(b011,b);@+} @+ break; +case TAG(vbox_kind,b100): @+{box_t b; @+HTEG_BOX(b100,b);@+} @+ break; +case TAG(vbox_kind,b101): @+{box_t b; @+HTEG_BOX(b101,b);@+} @+ break; +case TAG(vbox_kind,b110): @+{box_t b; @+HTEG_BOX(b110,b);@+} @+ break; +case TAG(vbox_kind,b111): @+{box_t b; @+HTEG_BOX(b111,b);@+} @+ break; +@ + +@<skip functions@>= +static void hteg_hbox_node(void) +{ box_t b; + @<skip the end byte |z|@>@; + if (KIND(z)!=hbox_kind) QUIT("Hbox expected at 0x%x got %s",node_pos,NAME(z)); + HTEG_BOX(INFO(z),b);@/ + @<skip and check the start byte |a|@>@; +} + +static void hteg_vbox_node(void) +{ box_t b; + @<skip the end byte |z|@>@; + if (KIND(z)!=vbox_kind) QUIT("Vbox expected at 0x%x got %s",node_pos,NAME(z)); + HTEG_BOX(INFO(z),b);@/ + @<skip and check the start byte |a|@>@; +} +@ + + +\subsection{Extended Boxes}\index{extended box} +\noindent +@<skip macros@>= +#define @[HTEG_SET(I)@] @/\ +{ list_t l; @+hteg_list(&l); @+} \ + if ((I)&b100) {xdimen_t x;@+ hteg_xdimen_node(&x); @+} \ + else HTEG_REF(xdimen_kind);\ +{ stretch_t m; @+HTEG_STRETCH(m);@+}\ +{ stretch_t p; @+HTEG_STRETCH(p);@+}\ +if ((I)&b010) { dimen_t a; @+HTEG32(a);@+} \ + { dimen_t w; @+HTEG32(w);@+} \ + { dimen_t d; @+if ((I)&b001) HTEG32(d); @+ else d=0;@+}\ + { dimen_t h; @+HTEG32(h);@+} +@# + +#define @[HTEG_PACK(K,I)@] @/\ + { list_t l; @+hteg_list(&l); @+} \ + if ((I)&b100) {xdimen_t x; hteg_xdimen_node(&x);@+} @+ else HTEG_REF(xdimen_kind);\ + if (K==vpack_kind) { dimen_t d; @+HTEG32(d); @+ }\ + if ((I)&b010) { dimen_t d; @+HTEG32(d); @+ } +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(hset_kind,b000): HTEG_SET(b000); @+ break; +case TAG(hset_kind,b001): HTEG_SET(b001); @+ break; +case TAG(hset_kind,b010): HTEG_SET(b010); @+ break; +case TAG(hset_kind,b011): HTEG_SET(b011); @+ break; +case TAG(hset_kind,b100): HTEG_SET(b100); @+ break; +case TAG(hset_kind,b101): HTEG_SET(b101); @+ break; +case TAG(hset_kind,b110): HTEG_SET(b110); @+ break; +case TAG(hset_kind,b111): HTEG_SET(b111); @+ break;@# + +case TAG(vset_kind,b000): HTEG_SET(b000); @+ break; +case TAG(vset_kind,b001): HTEG_SET(b001); @+ break; +case TAG(vset_kind,b010): HTEG_SET(b010); @+ break; +case TAG(vset_kind,b011): HTEG_SET(b011); @+ break; +case TAG(vset_kind,b100): HTEG_SET(b100); @+ break; +case TAG(vset_kind,b101): HTEG_SET(b101); @+ break; +case TAG(vset_kind,b110): HTEG_SET(b110); @+ break; +case TAG(vset_kind,b111): HTEG_SET(b111); @+ break;@# + +case TAG(hpack_kind,b000): HTEG_PACK(hpack_kind,b000); @+ break; +case TAG(hpack_kind,b001): HTEG_PACK(hpack_kind,b001); @+ break; +case TAG(hpack_kind,b010): HTEG_PACK(hpack_kind,b010); @+ break; +case TAG(hpack_kind,b011): HTEG_PACK(hpack_kind,b011); @+ break; +case TAG(hpack_kind,b100): HTEG_PACK(hpack_kind,b100); @+ break; +case TAG(hpack_kind,b101): HTEG_PACK(hpack_kind,b101); @+ break; +case TAG(hpack_kind,b110): HTEG_PACK(hpack_kind,b110); @+ break; +case TAG(hpack_kind,b111): HTEG_PACK(hpack_kind,b111); @+ break;@# + +case TAG(vpack_kind,b000): HTEG_PACK(vpack_kind,b000); @+ break; +case TAG(vpack_kind,b001): HTEG_PACK(vpack_kind,b001); @+ break; +case TAG(vpack_kind,b010): HTEG_PACK(vpack_kind,b010); @+ break; +case TAG(vpack_kind,b011): HTEG_PACK(vpack_kind,b011); @+ break; +case TAG(vpack_kind,b100): HTEG_PACK(vpack_kind,b100); @+ break; +case TAG(vpack_kind,b101): HTEG_PACK(vpack_kind,b101); @+ break; +case TAG(vpack_kind,b110): HTEG_PACK(vpack_kind,b110); @+ break; +case TAG(vpack_kind,b111): HTEG_PACK(vpack_kind,b111); @+ break; +@ + + +\subsection{Leaders}\index{leaders} +\noindent +@<skip macros@>= +#define @[HTEG_LEADERS(I)@]@/ \ +if (KIND(hpos[-1])==rule_kind) hteg_rule_node(); \ +else if (KIND(hpos[-1])==hbox_kind) hteg_hbox_node();\ +else hteg_vbox_node();\ +if ((I)&b100) hteg_glue_node(); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(leaders_kind,1): @+ HTEG_LEADERS(1); @+break; +case TAG(leaders_kind,2): @+ HTEG_LEADERS(2); @+break; +case TAG(leaders_kind,3): @+ HTEG_LEADERS(3); @+break; +case TAG(leaders_kind,b100|1): @+ HTEG_LEADERS(b100|1); @+break; +case TAG(leaders_kind,b100|2): @+ HTEG_LEADERS(b100|2); @+break; +case TAG(leaders_kind,b100|3): @+ HTEG_LEADERS(b100|3); @+break; +@ + +\subsection{Baseline Skips}\index{baseline skip} +\noindent +@<skip macros@>= +#define @[HTEG_BASELINE(I,B)@] \ + if((I)&b010) hteg_glue_node(); \ + else {B.ls.p.o=B.ls.m.o=B.ls.w.w=0; @+B.ls.w.h=B.ls.w.v=B.ls.p.f=B.ls.m.f=0.0;@+}\ + if((I)&b100) hteg_glue_node(); \ + else {B.bs.p.o=B.bs.m.o=B.bs.w.w=0; @+B.bs.w.h=B.bs.w.v=B.bs.p.f=B.bs.m.f=0.0;@+}\ + if((I)&b001) HTEG32((B).lsl); @+else B.lsl=0; +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(baseline_kind,b001): @+{ baseline_t b;@+ HTEG_BASELINE(b001,b);@+ }@+break; +case TAG(baseline_kind,b010): @+{ baseline_t b;@+ HTEG_BASELINE(b010,b);@+ }@+break; +case TAG(baseline_kind,b011): @+{ baseline_t b;@+ HTEG_BASELINE(b011,b);@+ }@+break; +case TAG(baseline_kind,b100): @+{ baseline_t b;@+ HTEG_BASELINE(b100,b);@+ }@+break; +case TAG(baseline_kind,b101): @+{ baseline_t b;@+ HTEG_BASELINE(b101,b);@+ }@+break; +case TAG(baseline_kind,b110): @+{ baseline_t b;@+ HTEG_BASELINE(b110,b);@+ }@+break; +case TAG(baseline_kind,b111): @+{ baseline_t b;@+ HTEG_BASELINE(b111,b);@+ }@+break; +@ +\subsection{Ligatures}\index{ligature} +\noindent +@<skip macros@>= +#define @[HTEG_LIG(I,L)@] @/\ +if ((I)==7) hteg_list(&((L).l)); \ +else {(L).l.s=(I); @+hpos-=(L).l.s; @+ (L).l.p=hpos-hstart;@+} \ +(L).f=HTEG8; +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(ligature_kind,1):@+ {lig_t l; @+HTEG_LIG(1,l);@+} @+break; +case TAG(ligature_kind,2):@+ {lig_t l; @+HTEG_LIG(2,l);@+} @+break; +case TAG(ligature_kind,3):@+ {lig_t l; @+HTEG_LIG(3,l);@+} @+break; +case TAG(ligature_kind,4):@+ {lig_t l; @+HTEG_LIG(4,l);@+} @+break; +case TAG(ligature_kind,5):@+ {lig_t l; @+HTEG_LIG(5,l);@+} @+break; +case TAG(ligature_kind,6):@+ {lig_t l; @+HTEG_LIG(6,l);@+} @+break; +case TAG(ligature_kind,7):@+ {lig_t l; @+HTEG_LIG(7,l);@+} @+break; +@ + + +\subsection{Discretionary breaks}\index{discretionary breaks} +\noindent +@<skip macros@>= +#define @[HTEG_DISC(I,H)@]\ +if ((I)&b001) hteg_list(&((H).q)); else { (H).q.p=hpos-hstart; @+(H).q.s=0; @+(H).q.k=list_kind; @+}\ +if ((I)&b010) hteg_list(&((H).p)); else { (H).p.p=hpos-hstart; @+(H).p.s=0; @+(H).p.k=list_kind; @+} \ +if ((I)&b100) (H).r=HTEG8; @+else (H).r=0; +@ +@<cases to skip content@>= +@t\1\kern1em@>case TAG(disc_kind,b001): @+{disc_t h; @+HTEG_DISC(b001,h); @+} @+break; +case TAG(disc_kind,b010): @+{disc_t h; @+HTEG_DISC(b010,h); @+} @+break; +case TAG(disc_kind,b011): @+{disc_t h; @+HTEG_DISC(b011,h); @+} @+break; +case TAG(disc_kind,b100): @+{disc_t h; @+HTEG_DISC(b100,h); @+} @+break; +case TAG(disc_kind,b101): @+{disc_t h; @+HTEG_DISC(b101,h); @+} @+break; +case TAG(disc_kind,b110): @+{disc_t h; @+HTEG_DISC(b110,h); @+} @+break; +case TAG(disc_kind,b111): @+{disc_t h; @+HTEG_DISC(b111,h); @+} @+break; +@ + + +\subsection{Paragraphs}\index{paragraph} +\noindent +@<skip macros@>= +#define @[HTEG_PAR(I)@] @/\ + { list_t l; @+hteg_list(&l); @+} \ + if ((I)&b010) { list_t l; @+hteg_param_list(&l); @+} else if ((I)!=b100) HTEG_REF(param_kind);\ + if ((I)&b100) {xdimen_t x; @+ hteg_xdimen_node(&x); @+} else HTEG_REF(xdimen_kind);\ + if ((I)==b100) HTEG_REF(param_kind); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(par_kind,b000): @+HTEG_PAR(b000);@+break; +case TAG(par_kind,b010): @+HTEG_PAR(b010);@+break; +case TAG(par_kind,b100): @+HTEG_PAR(b100);@+break; +case TAG(par_kind,b110): @+HTEG_PAR(b110);@+break; +@ + + +\subsection{Mathematics}\index{mathematics}\index{displayed formula}% +\noindent +@<skip macros@>= +#define @[HTEG_MATH(I)@] \ +if ((I)&b001) hteg_hbox_node();\ +{ list_t l; @+hteg_list(&l); @+} \ +if ((I)&b010) hteg_hbox_node(); \ +if ((I)&b100) { list_t l; @+hteg_param_list(&l); @+} @+ else HTEG_REF(param_kind); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(math_kind,b000): HTEG_MATH(b000); @+ break; +case TAG(math_kind,b001): HTEG_MATH(b001); @+ break; +case TAG(math_kind,b010): HTEG_MATH(b010); @+ break; +case TAG(math_kind,b100): HTEG_MATH(b100); @+ break; +case TAG(math_kind,b101): HTEG_MATH(b101); @+ break; +case TAG(math_kind,b110): HTEG_MATH(b110); @+ break; +case TAG(math_kind,b011): +case TAG(math_kind,b111): @+ break; +@ + +\subsection{Images}\index{image} +\noindent +@<skip macros@>= +#define @[HTEG_IMAGE(I,X)@] @/\ +if (I&b001) {HTEG_STRETCH((X).m);HTEG_STRETCH((X).p);@+}\ +else { (X).p.f=(X).m.f=0.0; (X).p.o=(X).m.o=normal_o;@+}\ +if (I&b010) {HTEG32((X).h);HTEG32((X).w);@+} \ +else (X).w=(X).h=0;\ +HTEG16((X).n); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(image_kind,b100): @+ { image_t x;@+HTEG_IMAGE(b100,x);@+}@+break; +case TAG(image_kind,b101): @+ { image_t x;@+HTEG_IMAGE(b101,x);@+}@+break; +case TAG(image_kind,b110): @+ { image_t x;@+HTEG_IMAGE(b110,x);@+}@+break; +case TAG(image_kind,b111): @+ { image_t x;@+HTEG_IMAGE(b111,x);@+}@+break; +@ + +\subsection{Links and Labels} +\noindent +@<skip macros@>= +#define @[HTEG_LINK(I)@] @/\ +{ uint16_t n; if (I&b001) HTEG16(n);@+ else n=HTEG8; @+} +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(link_kind,b000): @+ HTEG_LINK(b000); @+break; +case TAG(link_kind,b001): @+ HTEG_LINK(b001); @+break; +case TAG(link_kind,b010): @+ HTEG_LINK(b010); @+break; +case TAG(link_kind,b011): @+ HTEG_LINK(b011); @+break; +@ + + +\subsection{Plain Lists, Texts, and Parameter Lists}\index{list} + +\noindent +@<shared skip functions@>= +void hteg_size_boundary(info_t info) +{ uint32_t n; + if (info<2) return; + n=HTEG8; + if (n-1!=0x100-info) QUIT(@["List size boundary byte 0x%x does not match info value %d at " SIZE_F@], + n, info,hpos-hstart); +} + +uint32_t hteg_list_size(info_t info) +{ uint32_t n; + if (info==1) return 0; + else if (info==2) n=HTEG8; + else if (info==3) HTEG16(n); + else if (info==4) HTEG24(n); + else if (info==5) HTEG32(n); + else QUIT("List info %d must be 1, 2, 3, 4, or 5",info); + return n; +} + +void hteg_list(list_t *l) +{ @<skip the end byte |z|@>@, + @+if (KIND(z)!=list_kind && KIND(z)!=text_kind &&@| KIND(z)!=param_kind) @/ + QUIT("List expected at 0x%x", (uint32_t)(hpos-hstart)); + else + { uint32_t s; + l->k=KIND(z); + l->s=hteg_list_size(INFO(z)); + hteg_size_boundary(INFO(z)); + hpos=hpos-l->s; + l->p=hpos-hstart; + hteg_size_boundary(INFO(z)); + s=hteg_list_size(INFO(z)); + if (s!=l->s) QUIT(@["List sizes at " SIZE_F " and 0x%x do not match 0x%x != 0x%x"@], + hpos-hstart,node_pos-1,s,l->s); + @<skip and check the start byte |a|@>@; + } +} + +void hteg_param_list(list_t *l) +{ @+if (KIND(*(hpos-1))!=param_kind) return; + hteg_list(l); +} + + +@ + +\subsection{Adjustments}\index{adjustment} +\noindent +@<cases to skip content@>= +@t\1\kern1em@>case TAG(adjust_kind,b001): @+ { list_t l; @+hteg_list(&l);@+ } @+ break; +@ + +\subsection{Tables}\index{table} +\noindent +@<skip macros@>= +#define @[HTEG_TABLE(I)@] \ +{@+ list_t l; @+ hteg_list(&l);@+}\ +{@+ list_t l; @+ hteg_list(&l);@+}\ +if ((I)&b100) {xdimen_t x;@+ hteg_xdimen_node(&x);@+} else HTEG_REF(xdimen_kind)@; +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(table_kind,b000): @+ HTEG_TABLE(b000); @+ break; +case TAG(table_kind,b001): @+ HTEG_TABLE(b001); @+ break; +case TAG(table_kind,b010): @+ HTEG_TABLE(b010); @+ break; +case TAG(table_kind,b011): @+ HTEG_TABLE(b011); @+ break; +case TAG(table_kind,b100): @+ HTEG_TABLE(b100); @+ break; +case TAG(table_kind,b101): @+ HTEG_TABLE(b101); @+ break; +case TAG(table_kind,b110): @+ HTEG_TABLE(b110); @+ break; +case TAG(table_kind,b111): @+ HTEG_TABLE(b111); @+ break;@# + +case TAG(item_kind,b000): @+{@+ list_t l; @+hteg_list(&l);@+ } @+ break; +case TAG(item_kind,b001): hteg_content_node(); @+ break; +case TAG(item_kind,b010): hteg_content_node(); @+ break; +case TAG(item_kind,b011): hteg_content_node(); @+ break; +case TAG(item_kind,b100): hteg_content_node(); @+ break; +case TAG(item_kind,b101): hteg_content_node(); @+ break; +case TAG(item_kind,b110): hteg_content_node(); @+ break; +case TAG(item_kind,b111): hteg_content_node(); @+{uint8_t n;@+ n=HTEG8;@+}@+ break; +@ + + + +\subsection{Stream Nodes}\index{stream} +@<skip macros@>= +#define @[HTEG_STREAM(I)@] @/\ +{ list_t l; @+hteg_list(&l); @+}\ +if ((I)&b010) { list_t l; @+hteg_param_list(&l); @+} @+ else HTEG_REF(param_kind);\ +HTEG_REF(stream_kind); +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(stream_kind,b000): HTEG_STREAM(b000); @+ break; +case TAG(stream_kind,b010): HTEG_STREAM(b010); @+ break; +@ + + + +\subsection{References}\index{reference} +\noindent +@<skip macros@>= +#define @[HTEG_REF(K)@] do@+{uint8_t n; @+ n=HTEG8;@+} @+ while (false) +@ + +@<cases to skip content@>= +@t\1\kern1em@>case TAG(penalty_kind,0): HTEG_REF(penalty_kind); @+break; +case TAG(kern_kind,b000): HTEG_REF(dimen_kind); @+break; +case TAG(kern_kind,b100): HTEG_REF(dimen_kind); @+break; +case TAG(kern_kind,b001): HTEG_REF(xdimen_kind); @+break; +case TAG(kern_kind,b101): HTEG_REF(xdimen_kind); @+break; +case TAG(ligature_kind,0): HTEG_REF(ligature_kind); @+break; +case TAG(disc_kind,0): HTEG_REF(disc_kind); @+break; +case TAG(glue_kind,0): HTEG_REF(glue_kind); @+break; +case TAG(language_kind,0): HTEG_REF(language_kind); @+break; +case TAG(rule_kind,0): HTEG_REF(rule_kind); @+break; +case TAG(image_kind,0): HTEG_REF(image_kind); @+break; +case TAG(leaders_kind,0): HTEG_REF(leaders_kind); @+break; +case TAG(baseline_kind,0): HTEG_REF(baseline_kind); @+break; +@ + + +\section{Code and Header Files}\index{code file}\index{header file} + +\subsection{{\tt basetypes.h}} +To define basic types in a portable way, we create an include file. +The macro |_MSC_VER| (Microsoft Visual C Version)\index{Microsoft Visual C} +is defined only if using the respective compiler. +\index{false+\\{false}}\index{true+\\{true}}\index{bool+\&{bool}} +@(basetypes.h@>= +#ifndef __BASETYPES_H__ +#define __BASETYPES_H__ +#include <stdlib.h> +#include <stdio.h> +#ifndef _STDLIB_H +#define _STDLIB_H +#endif +#ifdef _MSC_VER +#include <windows.h> +#define uint8_t UINT8 +#define uint16_t UINT16 +#define uint32_t UINT32 +#define uint64_t UINT64 +#define int8_t INT8 +#define int16_t INT16 +#define int32_t INT32 +#define bool BOOL +#define true (0==0) +#define false (!true) +#define __SIZEOF_FLOAT__ 4 +#define __SIZEOF_DOUBLE__ 8 +#define INT32_MAX (2147483647) +#define PRIx64 "I64x" +#pragma @[warning( disable : @[4244@]@t @> @[4996@]@t @> @[4127@])@] +#else +#include <stdint.h> +#include <stdbool.h> +#include <inttypes.h> +#include <unistd.h> +#ifdef WIN32 +#include <io.h> +#endif +#endif +typedef float float32_t; +typedef double float64_t; +#if __SIZEOF_FLOAT__!=4 +#error @=float32 type must have size 4@> +#endif +#if __SIZEOF_DOUBLE__!=8 +#error @=float64 type must have size 8@> +#endif +#endif +@ + + + +\subsection{{\tt hformat.h}}\index{hformat.h+{\tt hformat.h}} +The \.{hformat.h} file contains definitions of types, macros, variables and functions +that are needed in other compilation units. + +@(hformat.h@>= +#ifndef _HFORMAT_H_ +#define _HFORMAT_H_ +@<debug macros@>@; +@<debug constants@>@; +@<hint macros@>@; +@<hint basic types@>@; +@<default names@>@; + +extern const char *content_name[32]; +extern const char *definition_name[32]; +extern unsigned int debugflags; +extern FILE *hlog; +extern int max_fixed[32], max_default[32], max_ref[32], max_outline; +extern int32_t int_defaults[MAX_INT_DEFAULT+1]; +extern dimen_t dimen_defaults[MAX_DIMEN_DEFAULT+1]; +extern xdimen_t xdimen_defaults[MAX_XDIMEN_DEFAULT+1]; +extern glue_t glue_defaults[MAX_GLUE_DEFAULT+1]; +extern baseline_t baseline_defaults[MAX_BASELINE_DEFAULT+1]; +extern label_t label_defaults[MAX_LABEL_DEFAULT+1]; +extern signed char hnode_size[0x100]; + +#endif +@ +\subsection{{\tt hformat.c}}\index{hformat.c+{\tt hformat.c}}\index{mkhformat.c+{\tt mkhformat.c}} +For maximum flexibility and efficiency, the file {\tt hformat.c} +is generated by a \CEE\ program. +Here is the |main| program of {\tt mkhformat}: + +@(mkhformat.c@>= +#include <stdio.h> +#include "basetypes.h" +#include "hformat.h" +@<skip macros@>@; + +int max_fixed[32], max_default[32]; + +int32_t int_defaults[MAX_INT_DEFAULT+1]={0}; +dimen_t dimen_defaults[MAX_DIMEN_DEFAULT+1]={0}; +xdimen_t xdimen_defaults[MAX_XDIMEN_DEFAULT+1]={{0}}; +glue_t glue_defaults[MAX_GLUE_DEFAULT+1]={{{0}}}; +baseline_t baseline_defaults[MAX_BASELINE_DEFAULT+1]={{{{0}}}}; + +signed char hnode_size[0x100]={0}; +@<define |content_name| and |definition_name|@>@; +int main(void) +{ kind_t k; + int i; + + + printf("#include \"basetypes.h\"\n"@/ + "#include \"hformat.h\"\n\n");@/ + + @<print |content_name| and |definition_name|@>@; + + printf("int max_outline=-1;\n\n"); + + @<take care of variables without defaults@>@; + @<define |int_defaults|@>@; + @<define |dimen_defaults|@>@; + @<define |glue_defaults|@>@; + @<define |xdimen_defaults|@>@; + @<define |baseline_defaults|@>@; + @<define page defaults@>@; + @<define stream defaults@>@; + @<define range defaults@>@; + @<define |label_defaults|@>@; + @<print defaults@>@; + + @<initialize the |hnode_size| array@>@; + @<print the |hnode_size| variable@>@; + return 0; +} +@ + +The following code prints the arrays containing the default values. + +@<print defaults@>= + printf("int max_fixed[32]= {"); + for (k=0; k<32; k++)@/ + { printf("%d",max_fixed[k]);@+ + if (k<31) printf(", ");@+ + } + printf("};\n\n");@# + printf("int max_default[32]= {"); + for (k=0; k<32; k++)@/ + { printf("%d",max_default[k]);@+ + if (k<31) printf(", ");@+ + } + printf("};\n\n"); + printf("int max_ref[32]= {"); + for (k=0; k<32; k++)@/ + { printf("%d",max_default[k]);@+ + if (k<31) printf(", ");@+ + } + printf("};\n\n"); +@ + + +\subsection{{\tt hget.h}}\index{hget.h+{\tt hget.h}} +The \.{hget.h} file contains function prototypes for all the functions +that read the short format. + +@(hget.h@>= +@<hint types@>@; +@<directory entry type@>@; +@<shared get macros@>@; + +extern entry_t *dir; +extern uint16_t section_no, max_section_no; +extern uint8_t *hpos, *hstart, *hend, *hpos0; +extern uint64_t hin_size, hin_time; +extern uint8_t *hin_addr; + +extern label_t *labels; +extern char *hin_name; +extern bool hget_map(void); +extern void hget_unmap(void); + +extern void new_directory(uint32_t entries); +extern void hset_entry(entry_t *e, uint16_t i, @|uint32_t size, uint32_t xsize, char *file_name); + +extern void hget_banner(void); +extern void hget_section(uint16_t n); +extern void hget_entry(entry_t *e); +extern void hget_directory(void); +extern void hclear_dir(void); +extern bool hcheck_banner(char *magic); + +extern void hget_max_definitions(void); +extern uint32_t hget_utf8(void); +extern void hget_size_boundary(info_t info); +extern uint32_t hget_list_size(info_t info); +extern void hget_list(list_t *l); +extern uint32_t hget_utf8(void); +extern float32_t hget_float32(void); +extern float32_t hteg_float32(void); +extern void hteg_size_boundary(info_t info); +extern uint32_t hteg_list_size(info_t info); +extern void hteg_list(list_t *l); +extern void hff_hpos(void); +extern uint32_t hff_list_pos, hff_list_size; +extern uint8_t hff_tag; +@ + + + +\subsection{{\tt hget.c}}\index{hget.c+{\tt hget.c}} +@(hget.c@>= +#include "basetypes.h" +#include <string.h> +#include <math.h> +#include <zlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> + +#include "error.h" +#include "hformat.h" +#include "hget.h" + +@<common variables@>@; + +@<map functions@>@; +@<function to check the banner@>@; +@<directory functions@>@; + +@<get file functions@>@; +@<shared get functions@>@; +@<shared skip functions@>@; +@ + +\subsection{{\tt hput.h}}\index{hput.h+{\tt hput.h}} +The \.{hput.h} file contains function prototypes for all the functions +that write the short format. + + +@(hput.h@>= +@<put macros@>@; +@<hint macros@>@; +@<hint types@>@; +@<directory entry type@>@; +extern entry_t *dir; +extern uint16_t section_no, max_section_no; +extern uint8_t *hpos, *hstart, *hend, *hpos0; +extern int next_range; +extern range_pos_t *range_pos; +extern int *page_on; +extern label_t *labels; +extern int first_label; +extern int max_outline; +extern outline_t *outlines; + + +extern FILE *hout; +extern void new_directory(uint32_t entries); +extern void new_output_buffers(void); + +/* declarations for the parser */ +extern void hput_definitions_start(void); +extern void hput_definitions_end(void); +extern void hput_content_start(void); +extern void hput_content_end(void); + +extern void hset_label(int n,int w); +extern uint8_t hput_link(int n, int on); +extern void hset_outline(int m, int r, int d, uint32_t p); +extern void hput_label_defs(void); + +extern void hput_tags(uint32_t pos, uint8_t tag); +extern uint8_t hput_glyph(glyph_t *g); +extern uint8_t hput_xdimen(xdimen_t *x); +extern uint8_t hput_int(int32_t p); +extern uint8_t hput_language(uint8_t n); +extern uint8_t hput_rule(rule_t *r); +extern uint8_t hput_glue(glue_t *g); +extern uint8_t hput_list(uint32_t size_pos, list_t *y); +extern uint8_t hsize_bytes(uint32_t n); +extern void hput_txt_cc(uint32_t c); +extern void hput_txt_font(uint8_t f); +extern void hput_txt_global(ref_t *d); +extern void hput_txt_local(uint8_t n); +extern info_t hput_box_dimen(dimen_t h, dimen_t d, dimen_t w); +extern info_t hput_box_shift(dimen_t a); +extern info_t hput_box_glue_set(int8_t s, float32_t r, order_t o); +extern void hput_stretch(stretch_t *s); +extern uint8_t hput_kern(kern_t *k); +extern void hput_utf8(uint32_t c); +extern uint8_t hput_ligature(lig_t *l); +extern uint8_t hput_disc(disc_t *h); +extern info_t hput_span_count(uint32_t n); +extern uint8_t hput_image(image_t *x); +extern void hput_string(char *str); +extern void hput_range(uint8_t pg, bool on); +extern void hput_max_definitions(void); +extern uint8_t hput_dimen(dimen_t d); +extern uint8_t hput_font_head(uint8_t f, char *n, dimen_t s,@| uint16_t m, uint16_t y); +extern void hput_range_defs(void); +extern void hput_xdimen_node(xdimen_t *x); +extern void hput_directory(void); +extern void hput_hint(char * str); +extern void hput_list_size(uint32_t n, int i); +extern int hcompress_depth(int n, int c); +@ + + +\subsection{{\tt hput.c}}\label{writeshort}\index{hput.c+{\tt hput.c}} +\noindent +@(hput.c@>= +#include "basetypes.h" +#include <string.h> +#include <ctype.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <zlib.h> +#include "error.h" +#include "hformat.h" +#include "hput.h" + +@<common variables@>@; +@<shared put variables@>@; +@<directory functions@>@; +@<function to write the banner@>@; +@<put functions@>@; +@ + +\subsection{{\tt shrink.l}}\index{shrink.l+{\tt shrink.l}}\index{scanning} +The definitions for lex are collected in the file {\tt shrink.l} + +@(shrink.lex-in@>= +%{ +#include "basetypes.h" +#include "error.h" +#include "hformat.h" +#include "hput.h" + +@<enable bison debugging@>@; +#include "shrink-parser.h" + +@<scanning macros@>@;@+ +@<scanning functions@>@; +int yywrap (void )@+{ return 1;@+} +#ifdef _MSC_VER +#pragma warning( disable : 4267) +#endif +%} + +%option yylineno batch stack +%option debug +%option nounistd nounput noinput noyy_top_state + +@<scanning definitions@>@/ + +%% + +@<scanning rules@>@/ +::@=[a-z]+@> :< QUIT("Unexpected keyword '%s' in line %d",@|yytext,yylineno); >: +::@=.@> :< QUIT("Unexpected character '%c' (0x%02X) in line %d",@|yytext[0]>' '?yytext[0]:' ',yytext[0],yylineno); >: + +%% +@ + + + +\subsection{{\tt shrink.y}}\index{shrink.y+{\tt shrink.y}}\index{parsing} + +The grammar rules for bison are collected in the file {\tt shrink.y}. +% for the option %token-table use the command line parameter -k + + +@(shrink.yacc-in@>= +%{ +#include "basetypes.h" +#include <string.h> +#include <math.h> +#include "error.h" +#include "hformat.h" +#include "hput.h" +extern char **hfont_name; /* in common variables */ + +@<definition checks@>@; + +extern void hset_entry(entry_t *e, uint16_t i, @|uint32_t size, + uint32_t xsize, char *file_name); + +@<enable bison debugging@>@; +extern int yylex(void); + +@<parsing functions@>@; + +%} + + +@t{\label{union}\index{union}\index{parsing}}@> + + +%union {uint32_t u; @+ int32_t i; @+ char *s; @+ float64_t f; @+ glyph_t c; + @+ dimen_t @+d; stretch_t st; @+ xdimen_t xd; @+ kern_t kt; + @+ rule_t r; @+ glue_t g; @+ @+ image_t x; + @+ list_t l; @+ box_t h; @+ disc_t dc; @+ lig_t lg; + @+ ref_t rf; @+ info_t info; @+ order_t o; bool@+ b; + } + +@t{}@> + +%error_verbose +%start hint +@t@> +@<symbols@>@/ +%% +@<parsing rules@>@; +%% +@ + +\subsection{{\tt hishrink.c}}\index{hishrink.c+{\tt hishrink.c}} + +\.{shrink} is a \CEE\ program translating a \HINT\ file in long format into a \HINT\ file in short format. + +@(hishrink.c@>= +#include "basetypes.h" +#include <string.h> +#include <ctype.h> +#include <sys/types.h> +#include <sys/stat.h> +#ifdef WIN32 +#include <direct.h> +#endif +#include <zlib.h> + +#include "error.h" +#include "hformat.h" +#include "hput.h" +#include "shrink-parser.h" + +extern void yyset_debug(int lex_debug); +extern int yylineno; +extern FILE *yyin, *yyout; +extern int yyparse(void); + +@<put macros@>@; + +@<common variables@>@; +@<shared put variables@>@; +@<function to check the banner@>@; +@<directory functions@>@; +@<function to write the banner@>@; +@<put functions@>@; + +int main(int argc, char *argv[]) +{ @<local variables in |main|@>@; + in_ext=".HINT"; + out_ext=".hnt"; + @<process the command line@>@; + + if (debugflags&DBGFLEX) yyset_debug(1); else yyset_debug(0); +#if YYDEBUG + if (debugflags&DBGBISON) yydebug=1; + else yydebug=0; +#endif + @<open the log file@>@; + @<open the input file@>@; + @<open the output file@>@; + + yyin=hin; + yyout=hlog; + @<read the banner@>@; + if (!hcheck_banner("HINT")) QUIT("Invalid banner"); + yylineno++; + DBG(DBGBISON|DBGFLEX,"Parsing Input\n"); + yyparse(); + + hput_directory(); + + hput_hint("shrink"); + + @<close the output file@>@; + @<close the input file@>@; + @<close the log file@>@; + return 0; +explain_usage: + @<explain usage@>@; + return 1; +} +@ + + + +\subsection{{\tt histretch.c}}\label{stretchmain}\index{histretch.c+{\tt histretch.c}} +\.{histretch} is a \CEE\ program translating a \HINT\ file in short +format into a \HINT\ file in long format. + +@(histretch.c@>= +#include "basetypes.h" +#include <math.h> +#include <string.h> +#include <ctype.h> +#include <zlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#ifdef WIN32 +#include <direct.h> +#endif +#include <fcntl.h> +#include "error.h" +#include "hformat.h" +#include "hget.h" + +@<get macros@>@; +@<write macros@>@; +@<common variables@>@; +@<shared put variables@>@; +@<map functions@>@; +@<function to check the banner@>@; +@<function to write the banner@>@; +@<directory functions@>@; + +@<definition checks@>@; +@<get function declarations@>@; +@<write functions@>@; +@<get file functions@>@; +@<shared get functions@>@; +@<get functions@>@; + +int main(int argc, char *argv[]) +{ @<local variables in |main|@>@; + + in_ext=".hnt"; + out_ext=".HINT"; + @<process the command line@>@; + @<open the log file@>@; + @<open the output file@>@; + @<determine the |stem_name| from the output |file_name|@>@; + if (!hget_map()) QUIT("Unable to map the input file"); + hpos=hstart=hin_addr; + hend=hstart+hin_size; + hget_banner(); + if (!hcheck_banner("hint")) QUIT("Invalid banner"); + hput_banner("HINT","stretch"); + hget_directory(); + hwrite_directory(); + hget_definition_section(); + hwrite_content_section(); + hwrite_aux_files(); + hget_unmap(); + @<close the output file@>@; + DBG(DBGBASIC,"End of Program\n"); + @<close the log file@>@; + return 0; +explain_usage: + @<explain usage@>@; + return 1;} +@ + +In the above program, the get functions call the write functions +and the write functions call some get functions. This requires +function declarations to satisfy the define before use requirement +of \CEE. Some of the necessary function declarations are already +contained in {\tt hget.h}. The remaining declarations are these: + +@<get function declarations@>= +extern void hget_xdimen_node(xdimen_t *x); +extern void hget_def_node(void); +extern void hget_font_def(uint8_t f); +extern void hget_content_section(void); +extern uint8_t hget_content_node(void); +extern void hget_glue_node(void); +extern void hget_rule_node(void); +extern void hget_hbox_node(void); +extern void hget_vbox_node(void); +extern void hget_param_list(list_t *l); +extern int hget_txt(void); +@ + + +\subsection{{\tt skip.c}}\label{skip}\index{skip.c+{\tt skip.c}} +\.{skip} is a \CEE\ program reading the content section of a \HINT\ file in short format +backwards. + +@(skip.c@>= +#include "basetypes.h" +#include <string.h> +#include <zlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include "error.h" +#include "hformat.h" +@<hint types@>@; + +@<common variables@>@; + +@<map functions@>@; +@<function to check the banner@>@; +@<directory entry type@>@; +@<directory functions@>@; +@<shared get macros@>@; +@<get file functions@>@; + +@<skip macros@>@; +@<skip function declarations@>@; +@<shared skip functions@>@; +@<skip functions@>@; + +int main(int argc, char *argv[]) +{ @<local variables in |main|@>@; + in_ext=".hnt"; + out_ext=".bak"; + + @<process the command line@>@; + @<open the log file@>@; + if (!hget_map()) QUIT("Unable to map the input file"); + hpos=hstart=hin_addr; + hend=hstart+hin_size; + hget_banner(); + if (!hcheck_banner("hint")) QUIT("Invalid banner"); + hget_directory(); + DBG(DBGBASIC,"Skipping Content Section\n"); + hteg_content_section(); + DBG(DBGBASIC,"Fast forward Content Section\n"); + hpos=hstart; + while(hpos<hend) + { hff_hpos(); + if (KIND(*(hpos-1))==par_kind && KIND(hff_tag)==list_kind && hff_list_size>0) + { uint8_t *p=hpos,*q; + DBG(DBGTAGS,"Fast forward list at 0x%x, size %d",hff_list_pos,hff_list_size); + hpos=hstart+hff_list_pos; + q=hpos+hff_list_size; + while (hpos<q) + hff_hpos(); + hpos=p; + } + } + hget_unmap(); + @<close the log file@>@; + return 0; +explain_usage: + @<explain usage@>@; + return 1; +} +@ + +As we have seen already in the {\tt stretch} program, a few +function declarations are necessary to satisfy the define before +use requirement of \CEE. + +@<skip function declarations@>= +static void hteg_content_node(void); +static void hteg_content(uint8_t z); +static void hteg_xdimen_node(xdimen_t *x); +static void hteg_list(list_t *l); +static void hteg_param_list(list_t *l); +static float32_t hteg_float32(void); +static void hteg_rule_node(void); +static void hteg_hbox_node(void); +static void hteg_vbox_node(void); +static void hteg_glue_node(void); +@ + +\thecodeindex + +\crosssections + +\plainsection{References} + +{\baselineskip=11pt +\def\bfblrm{\small\rm}% +\def\bblem{\small\it}% +\bibliography{../hint} +\bibliographystyle{plain} +} + +\plainsection{Index} +{ +\def\_{{\tt \UL}} % underline in a string +\catcode`\_=\active \let_=\_ % underline is a letter +\input format.ind +} + +\write\cont{} % ensure that the contents file isn't empty +% \write\cont{\catcode `\noexpand\@=12\relax} % \makeatother +\closeout\cont% the contents information has been fully gathered diff --git a/Build/source/texk/web2c/hitexdir/hitex.w b/Build/source/texk/web2c/hitexdir/hitex.w new file mode 100644 index 00000000000..b56946e7421 --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/hitex.w @@ -0,0 +1,4753 @@ +% This file is part of HINT +% Copyright 2017-2021 Martin Ruckert +% +% Permission is hereby granted, free of charge, to any person obtaining a copy +% of this software and associated documentation files (the "Software"), to deal +% in the Software without restriction, including without limitation the rights +% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +% copies of the Software, and to permit persons to whom the Software is +% furnished to do so, subject to the following conditions: +% +% The above copyright notice and this permission notice shall be +% included in all copies or substantial portions of the Software. +% +% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +% COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, +% WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT +% OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +% THE SOFTWARE. +% +% Except as contained in this notice, the name of the copyright holders shall +% not be used in advertising or otherwise to promote the sale, use or other +% dealings in this Software without prior written authorization from the +% copyright holders. + +\input ../hint.sty +\input ../changefile.sty + +%% defining how to display certain C identifiers +@s uint8_t int +@s uint16_t int +@s uint32_t int +@s uint64_t int +@s int8_t int +@s int16_t int +@s int32_t int +@s float64_t int +@s float32_t int +@s scaled int +@s pointer int +@s memory_word int +@s ASCII_code int +@s small_number int +@s info_t int +@s lig_t int +@s disc_t int +@s math_t int +@s glyph_t int +@s glue_t int +@s rule_t int +@s list_t int +@s kind_t int +@s image_t int +@s glue_ord int +@s four_quarters int +@s eight_bits int +@s internal_font_number int +@s explicit normal +@s str_number int +@s dimen_t int +@s loop else +@s kpse_file_format_type int +@s font_t int + + +\makeindex +\maketoc + +%\makefigindex +\titletrue + +\def\lastrevision{${}$Revision: 2485 ${}$} +\def\lastdate{${}$Date: 2021-08-19 19:37:13 +0200 (Thu, 19 Aug 2021) ${}$} +\eject +\input titlepage.tex + + +\frontmatter + +@ + + +\plainsection{Preface} +To be written + +\vskip 1cm +\noindent {\it M\"unchen\hfil\break +August 20, 2018 \hfill Martin Ruckert} + + +\tableofcontent +%\thefigindex + + +\mainmatter + +\section{Introduction}\label{intro} +Hi\TeX\ is a modified version of \TeX\ that replaces the \.{DVI} +(device independent) output format by the \HINT\ format. The \HINT\ +format, described in \cite{MR:format}, was designed with two +objectives: being able to support reflowing pages using the \TeX\ +typesetting engine and making it simple to use it as output format of +the \TeX\ programm. The present book tries to convince its readers +that the latter claim is true. To this end, this book implements a +version of \TeX\ that produces \HINT\ output---to be precise: a short +format \HINT\ file. + +The book is written as a literate program\cite{Knuth:lp} using ``The +\.{CWEB} System of Structured Documentation''\cite{Knuth:cweb}. The +largest part of this program is, of course, \TeX\cite{Knuth:tex} +itself. Therefore a significant part of Hi\TeX\ consists of +modifications of the \TeX\ source code, which itself is written as a +literate program using ``The \.{WEB} System of Structured +Documentation''\cite{Knuth:WEB}. The tiny, but significant, +difference between \.{WEB}\index{WEB+{\tt WEB}} +and \.{CWEB}\index{CWEB+{\tt CWEB}} is the transition from +\Pascal\ to \CEE/ as target language. To bridge the gap between +\.{WEB} and \.{CWEB}, Hi\TeX\ is not based on the original \.{WEB} +implementation of \TeX\ but on the \.{CWEB} implementation of \TeX\ +as described in~\cite{MR:webtocweb} and~\cite{MR:web2w}. +Further, it does not use the plain {\tt ctex.w} translation of {\tt tex.web} +but the {\tt ktex.w} file which extends \TeX\ with + the features of $\epsilon$-\TeX, the file searching +mechanisms of the {\tt kpathsearch} library, and the command line +conventions of \TeX\ Live. + +To accomplish modifications of a \.{CWEB} file, the \.{CWEB} tools +support the use of ``change files''. These change files are lists of +code changes optionally embellished with explanatory text. Each code +change consists of two parts: a literal copy of the original source +code followed by the replacement text. When a \.{CWEB} tool applies +such a change file to a cweb file, it will read both files +sequentially and applies the code changes in the order given: Whenever +it finds a section in the \.{CWEB} file that matches the first part of +the current code change, it will replace it by the second part of the +code change, and advance to the next code change. + +The present book makes an attempt to present these code changes in +``literate programming style'' and had to overcome two obstacles: +First, in a literate program, the exposition determines the order of +appearance of the code sections; and second, the tools that generate +the documentation from a \.{CWEB} file are not able to generate +documentation for a change file. + +The first problem can be solved by using the program {\tt +tie}\cite{kg:tie}\cite{jg:ctie}. It allows splitting a single change +file into multiple change files, and while within each change file, +the order of changes is still determined by the original cweb file, +changes that belong together can be grouped into separate files. + +The second problem is solved by a simple preprocessor, that converts +change files into cweb files which then can be converted into +\TeX. With the help of some modifications of the macros in {\tt +cwebmac.tex} these \TeX\ files are used to present change files in +this book. + +Let's look at an examples to explain and illustrate the presentation +of code changes in this book: the {\tt display\_node.ch} change file. + +\subsection{The Function |display_node|} +It is the purpose of the {\tt display\_node.ch} change file to make +the \TeX\ code contained in the section ``\<Display node |p|>'' +available to other parts of Hi\TeX\ as a function. +The function is then used to display debugging output. + +This requires the following changes: + +\changestyle{displaynode.tex} + +As you can see, the two parts of a code change are enclosed in square brackets +where the opening top bracket is labeled {\it old\/} or {\it new\/}. +While a full understanding of these code changes requires a look at the original \TeX\ code, +at least they document what was done and why. + +There is still one thing missing before we can use the |display_node| +function in the {\tt hitex.c} file we are about to generate: +we need an |extern| declaration of |display_node|. +In fact, the Hi\TeX\ program contains a whole bunch of functions +that will need access to \TeX's internals and the most readable +and convenient way to gain this access is a header file. + +Generating such a header file can be accomplished by using the {\tt -h} +and {\tt -e} options of the {\tt web2w} program when converting the {\tt WEB} +source of \TeX\ to its {\tt cweb} source. We just need to modify the +process slightly for our purposes. + +{ +\changestyle{types.tex} +} + + +\section{Modifying \TeX}\label{modifyingTeX} +In this section, we explain the different change files that modify \TeX. +Larger changes are accomplished by replacing entire functions. + + +\subsection{The |main| Program} +We add two function calls to \TeX's |main| program: +|hint_open|, and |hint_close|. + +{ +\changestyle{main.tex} +} +The functions to open and close the \HINT\ file follow in +section~\secref{output}. + + +\subsection{The Command Line} +Hi\TeX\ has a few additional command line options that we define next. + +{ +\changestyle{command_line.tex} +} + +Above we used the function |hint_debug_help|. It is defined as: + +@<Hi\TeX\ routines@>= +#ifdef DEBUG +void hint_debug_help(void) +{ +fprintf(stderr,@/ + "To generate HINT format debug output use the option\n" + " -debug=XX "@/ +@t\qquad@>"\t XX is a hexadecimal value. OR together these values:\n");@/ +fprintf(stderr,"\t\t\t XX=%04X \t basic debugging\n", DBGBASIC);@/ +fprintf(stderr,"\t\t\t XX=%04X \t tag debugging\n", DBGTAGS);@/ +fprintf(stderr,"\t\t\t XX=%04X \t node debugging\n",DBGNODE);@/ +fprintf(stderr,"\t\t\t XX=%04X \t definition debugging\n", DBGDEF);@/ +fprintf(stderr,"\t\t\t XX=%04X \t directory debugging\n", DBGDIR);@/ +fprintf(stderr,"\t\t\t XX=%04X \t range debugging\n",DBGRANGE);@/ +fprintf(stderr,"\t\t\t XX=%04X \t float debugging\n", DBGFLOAT);@/ +fprintf(stderr,"\t\t\t XX=%04X \t compression debugging\n", DBGCOMPRESS);@/ +fprintf(stderr,"\t\t\t XX=%04X \t buffer debugging\n", DBGBUFFER);@/ +fprintf(stderr,"\t\t\t XX=%04X \t TeX debugging\n", DBGTEX);@/ +fprintf(stderr,"\t\t\t XX=%04X \t page debugging\n", DBGPAGE);@/ +fprintf(stderr,"\t\t\t XX=%04X \t font debugging\n", DBGFONT);@/ +exit(0); +} +#endif +@ + + + +\subsection{The Page Builder}\label{pagebuilder} +The point where Hi\TeX\ goes an entirely different path than \TeX\ is the page builder: +Instead of building a page, Hi\TeX\ writes a \HINT\ file. + +{ +\changestyle{build.tex} +} + + + +\subsection{Adding new {\tt whatsit} Nodes} +\TeX\ has a mechanism to extend it: the {\tt whatsit} nodes. +For new concepts like baseline specifications, paragraphs, and boxes with unknown dimensions, +we define now special {\tt whatsit} nodes. The new node definitions are supplemented by +procedures to print them, copy them, delete them, and handle them in various contexts. + +{ +\changestyle{whatsit.tex} +} + +\subsubsection{Freeing} +Because some of the new nodes occur at places where \TeX\ originaly only +handles box nodes, +there are many places in \TeX\ where we can no longer just say |free_node(b, box_node_size)| +to free a (box) node. +Instead, we have to use the more general routine |flush_node_list|. +This leads to a long series of simple replacements: + +{ +\changestyle{free.tex} +} + +\subsubsection{Unpacking} +In the function |unpackage| the pointer |p| might now point to an +hset, vset, hpack or vpack node instead of a vbox or hbox node. +We have to adapte the following test to this new situation. + +{ +\changestyle{unpackage.tex} +} + +We continue to define auxiliar functions to create the new nodes. + +\subsubsection{Creating} + +The following functions create nodes for paragraphs, displayed equations, baseline skips, +hpack nodes, vpack nodes, hset nodes, vset nodes, and image nodes. + +@<Hi\TeX\ routines@>= +pointer new_graf_node(void) +{ @+ pointer p; + p=get_node(graf_node_size); + type(p)=whatsit_node; + subtype(p)=graf_node; + graf_params(p)=null; + graf_list(p)=null; + return p; +} + + +pointer new_disp_node(void) +{ @+ pointer p; + p=get_node(disp_node_size); + type(p)=whatsit_node; + subtype(p)=disp_node; + display_params(p)=null; + display_formula(p)=null; + display_eqno(p)=null; + return p; +} + +pointer new_baseline_node(pointer bs, pointer ls, scaled lsl) +{ @+pointer p; + p=get_node(baseline_node_size); + type(p)=whatsit_node; + subtype(p)=baseline_node; + baseline_node_no(p)=hget_baseline_no(bs, ls, lsl); + return p; +} + +pointer new_pack_node(void) +{ @+pointer p; + p=get_node(pack_node_size); + type(p)=whatsit_node; + subtype(p)=hpack_node; + width(p)=depth(p)=height(p)=shift_amount(p)=0; + pack_limit(p)=max_dimen; + list_ptr(p)=null; + return p; +} +pointer new_set_node(void) +{ @+pointer p; + p=get_node(set_node_size); + type(p)=whatsit_node; + subtype(p)=hset_node; + width(p)=depth(p)=height(p)=shift_amount(p)=set_stretch(p)=set_shrink(p)=set_extent(p)=0; + list_ptr(p)=null; + return p; +} + + + + +pointer new_image_node( str_number n, char *a, char *e) +{ pointer p; + int i; + char *fn; + int l; + + p=get_node(image_node_size);type(p)=whatsit_node;subtype(p)=image_node; + image_name(p)=n; + image_area(p)=s_no(a); + image_ext(p)=s_no(e); + fn=hfile_name(n,a,e); +#if 0 + fn=kpse_find_tex(fn); +#endif + i=hnew_file_section(fn); +#if 0 + free(fn); +#endif + image_no(p)=i; + image_width(p)=image_height(p)=image_stretch(p)=image_shrink(p)=0; + image_shrink_order(p)=image_stretch_order(p)=normal;@/ + return p; +} + + + +@ + +\subsubsection{Parameter nodes} + +Parameter nodes are added to the current list using the |add_par_node| function. +It should be possible to check the parameter values against those +stored in the definition section and remove the ones that +are unchanged. It would make the parameter lists shorter, saving +some time when setting and restoring them later. +There is probably not much savings in memory space, because +most of the times a reference number is found for the parameter list. +@<Create the parameter node@>= + p=get_node(par_node_size); + type(p)=whatsit_node; + subtype(p)=par_node; + par_type(p)=t; + par_number(p)=n; +@ + +@<Initialize the parameter node@>= + if (t==int_type) par_value(p).i=v; + else if (t==dimen_type) par_value(p).sc=v; + else if (t==glue_type) + {@+ par_value(p).i=v;add_glue_ref(par_value(p).i); @+} + else + { free_node(p, par_node_size); + QUIT("Undefined parameter type %d",t); + } +@ + +@<Hi\TeX\ routines@>= +void add_par_node(uint8_t t, uint8_t n, int v) +{ @+pointer p; + @<Create the parameter node@>@; + @<Initialize the parameter node@>@; + link(p)=link(temp_head); + link(temp_head)=p; +} +@ + + +\subsection{Extended Dimensions} +An extended dimension is a linar function of {\tt hsize} and {\tt vsize}, and +whenever \TeX\ works with a dimension, we want it to be able to deal with +an extended dimension. This implies many changes throughout \TeX's sources. +So let's get started. + +{ +\changestyle{xdimen.tex} +} + + + + +\subsection{Hyphenation} +While the breaking of a paragraph into lines must be postponed because +{\tt hsize} is not known, hyphenation should be done as part of Hi\TeX\ +because we want to keep hyphenation out of the viewer. Therefore +Hi\TeX\ will do hyphenation for all words within a paragraph. + +There is a fine point to observe here: \TeX\ will consider a word as +a candidate for automatic hyphenation only if the world ``follows'' after a +glue. (For the exact rules, see the \TeX book\cite{DK:texbook}, Appendix H.) +As a consequence, \TeX\ usually does not submit the first word of a +paragraph to its hyphenation routine. +Viewing paragraphs that start with a lengthy word on a narrow display +therefore often look more unsightly than necessary: the long word sticks out +into the right margin as much as it can. To remedy this situation, +Hi\TeX\ has a ``{\tt -f}'' option. If set Hi\TeX\ will deviate from +\TeX's rules and submit the first word of a paragraph to the hyphenation algorithm. + +The next problem arises from \TeX's multipass approach to line breaking +and the attempt to have Hi\TeX\ choose exactly the same line breaks as +\TeX\ does: +\TeX\ distingishes between discretionary breaks inserted by the author of a +text, and discretionary breaks discovered by the hyphenation routine. +The latter, called here ``automatic'', are used only in pass two and three +of the line breaking routine. + +The change file that follows below contains mostly three types of changes: +\itemize +\item Hi\TeX\ restricts the |replace_count| to seven bit to make room for an +extra bit to mark automatic discretionary breaks. +Assignments to the replace count are therefore replaced by a macro that +protects the automatic bit. +\item The \TeX\ code for ``\<Try to hyphenate the following word>'' +is packaged into a function |hyphenate_word|, so that it can be invoked as needed. +\item And calls of the function |line_break| are replaced by calls to |hline_break| +to have a hook for inserting Hi\TeX specific changes. +\enditemize + +{ +\changestyle{disc.tex} +} + +The function |hline_break| follows: + + +@<Hi\TeX\ routines@>= +void hline_break(int final_widow_penalty) +{@+ bool auto_breaking; /*is node |cur_p| outside a formula?*/ + pointer r, s ; /*miscellaneous nodes of temporary interest*/ + pointer pp; + bool par_shape_fix=false; + bool first_word=true; + if (DBGTEX&debugflags) + { print_ln();print("Before hline_break:\n"); + breadth_max=200; + depth_threshold=200; + show_node_list(link(head));print_ln(); + } + if (dimen_par_hfactor(hsize_code)==0 && dimen_par_vfactor(hsize_code)==0) + { line_break(final_widow_penalty); /* the easy case */ + return; + } + /* Get ready to start line breaking */ + pp=new_graf_node(); + graf_penalty(pp)=final_widow_penalty; + if(par_shape_ptr==null) + graf_extent(pp)=new_xdimen(dimen_par(hsize_code), + dimen_par_hfactor(hsize_code),dimen_par_vfactor(hsize_code)); + else + @<fix the use of parshape = 1 indent length@>@; + link(temp_head)=link(head); + if (is_char_node(tail)) + { tail_append(new_penalty(inf_penalty))@; + tail_append(new_param_glue(par_fill_skip_code)); + } + else if (type(tail)!=whatsit_node || subtype(tail)!=disp_node) + { if (type(tail)!=glue_node) tail_append(new_penalty(inf_penalty))@; + else + {@+type(tail)=penalty_node;delete_glue_ref(glue_ptr(tail)); + flush_node_list(leader_ptr(tail));penalty(tail)=inf_penalty; + } + link(tail)=new_param_glue(par_fill_skip_code); + } + DBG(DBGTEX,"\nCalling line_break:\n" + "hang_indent=0x%08X hang_after=%d",hang_indent,hang_after); + if (line_skip_limit!=0) + DBG(DBGTEX," line_skip_limit=0x%08X",line_skip_limit); + DBG(DBGTEX," prev_graf=0x%08X",prev_graf); + + init_cur_lang=prev_graf%0200000; + init_l_hyf=prev_graf/020000000; + init_r_hyf=(prev_graf/0200000)%0100; + pop_nest(); + DBG(DBGTEX," prev_graf=0x%08X",prev_graf); + + /* Initialize for hyphenating...*/ +#ifdef INIT + if (trie_not_ready) init_trie(); +#endif + cur_lang=init_cur_lang;l_hyf=init_l_hyf;r_hyf=init_r_hyf; + if (DBGTEX&debugflags) + { print_ln();print("Before hyphenation:\n"); + breadth_max=200; + depth_threshold=200; + show_node_list(link(temp_head));print_ln(); + } + auto_breaking=true; + cur_p=temp_head; + if (option_hyphen_first && is_char_node(link(cur_p))) + { hyphenate_word(); first_word=false; } + cur_p=link(cur_p); + while (cur_p!=null) + { /*Call |try_break| if |cur_p| is a legal breakpoint...*/ + if (is_char_node(cur_p)) + { /* Advance |cur_p| to the node following the present string...*/ + do { + cur_p=link(cur_p); + } while (is_char_node(cur_p)); + if (cur_p==null) goto done5; /* mr: no glue and penalty at the end */ + } + switch (type(cur_p)) + { case whatsit_node: + adv_past(cur_p); + break; + case glue_node: + if (auto_breaking) /* Try to hyphenate the following word*/ + hyphenate_word(); + break; + case ligature_node: + break; + case disc_node: + /* Try to break after a discretionary fragment...*/ + r=replace_count(cur_p);s=link(cur_p); + while (r > 0) + { decr(r);s=link(s); + } + cur_p=s; + goto done5; + case math_node: + auto_breaking=(subtype(cur_p)==after); + break; + default: + break; + } + if (option_hyphen_first && first_word && is_char_node(link(cur_p))) + { hyphenate_word(); first_word=false; } + cur_p=link(cur_p); +done5:; + } + if (DBGTEX&debugflags) + { print_ln();print("After hline_break:\n"); + breadth_max=200; + depth_threshold=200; + show_node_list(link(temp_head));print_ln(); + } + graf_list(pp)=link(temp_head); + /* adding parameter nodes */ + link(temp_head)=null; + + add_par_node(int_type,pretolerance_code,pretolerance); + add_par_node(int_type,tolerance_code,tolerance); + add_par_node(dimen_type,emergency_stretch_code,emergency_stretch); + + add_par_node(int_type,line_penalty_code,line_penalty); + add_par_node(int_type,hyphen_penalty_code,hyphen_penalty); + add_par_node(int_type,ex_hyphen_penalty_code,ex_hyphen_penalty); + add_par_node(int_type,club_penalty_code,club_penalty); + add_par_node(int_type,widow_penalty_code,widow_penalty); + add_par_node(int_type,broken_penalty_code,broken_penalty); + add_par_node(int_type,inter_line_penalty_code,inter_line_penalty); + add_par_node(int_type,double_hyphen_demerits_code,double_hyphen_demerits); + add_par_node(int_type,final_hyphen_demerits_code,final_hyphen_demerits); + add_par_node(int_type,adj_demerits_code,adj_demerits); + add_par_node(int_type,looseness_code,looseness); + + if (par_shape_fix) + { add_par_node(int_type,hang_after_code,0); + add_par_node(dimen_type,hang_indent_code,second_indent); + } + else + { add_par_node(int_type,hang_after_code,hang_after); + add_par_node(dimen_type,hang_indent_code, hang_indent); + } + + add_par_node(dimen_type,line_skip_limit_code,line_skip_limit); + add_par_node(glue_type,line_skip_code,line_skip); + add_par_node(glue_type,baseline_skip_code,baseline_skip); + + add_par_node(glue_type,left_skip_code,left_skip); + add_par_node(glue_type,right_skip_code,right_skip); + add_par_node(glue_type,par_fill_skip_code,par_fill_skip); + + + /* |par_shape| is not yet supported */ + graf_params(pp)=link(temp_head); + link(temp_head)=null; + append_to_vlist(pp); +} +@ + +Currently Hi\TeX\ dos not implement the parshape feature of \TeX. +The implementation of {\tt \BS list} in \LaTeX\ does however depend +on a simple us of parshape where all lines have the same length +and indentation. We cover this special case be using a hanging +indentation and adjusting the paragraph width by the difference +of the normal {\tt \BS hsize} and the given length. + +@<fix the use of parshape = 1 indent length@>= +{ last_special_line= info(par_shape_ptr)-1; + if (last_special_line!=0) + DBG(DBGTEX,"Warning parshape with n=%d not yet implemented",info(par_shape_ptr)); + second_width= mem[par_shape_ptr+2*(last_special_line+1)].sc; + second_indent= mem[par_shape_ptr+2*last_special_line+1].sc; + + graf_extent(pp)=new_xdimen(second_indent+second_width, + par_shape_hfactor,par_shape_vfactor); + second_width=second_width+ round((double)par_shape_hfactor*hhsize/unity + +(double)par_shape_vfactor*hvsize/unity); + par_shape_fix=true; +} +@ + +\subsection{Baseline Skips} + +\TeX\ will automatically insert a baseline skip between two boxes in a +vertical list. The baseline skip is computed to make the distance +between the baselines of the two boxes exactly equal to the value of +{\tt \BS baselineskip}. And if that is not possible, because it would +make the distance between the descenders of the upper box and the +ascenders of the lower box smaller than {\tt \BS lineskiplimit}, it +will insert at least a small amount of glue of size {\tt \BS +lineskip}. As a further complication, if the depth of the upper box +has the special value |ignore_depth| the insertion of a baseline skip +is suppressed. It is also common practice that authors manipulate the +values of {\tt \BS baselineskip}, {\tt \BS lineskiplimit}, {\tt \BS +lineskip}, and {\tt \BS prevdepth} to change the baseline calculations +of \TeX. + +Of course a prerequisite of the whole computation of a baseline skip +is the knowledge of the depth of the upper box and the height of the +lower box. With the new types of boxes introduced by Hi\TeX\ neither +of them might be known. In these cases, the baseline skip computation +must be defered to the viewer by inserting a whatsit node of subtype +|baseline_node|. + + +{ +\changestyle{baseline.tex} +} + + +\subsection{Displayed Formulas} + +\TeX\ enters into math mode when it finds a math shift character ``\$''. +Then it calls |init_math| which checks for an aditional math shift +character to call either + \<Go into ordinary math mode> or \<Go into display math mode>. +We remove most of the differences from the latter because we will +treat both cases very similar here and will consider the necessary +differences in the \HINT\ viewer. + +When the shift character that terminates math more is encountered, +\TeX\ calls |after_math| which ends with +either \<Finish math in text> or \<Finish displayed math> . +We need to modify the latter, because positioning a displayed +equation usually depends on {\tt hsize}, +and must be postponed until the viewer knows its value. +So all Hi\TeX\ can do in this case is create a new whatsit node +with subtype |disp_node| and +insert it proceeding as if the formula had occured in ordinary math mode. + + +{ +\changestyle{display.tex} +} + + + + +\subsection{Alignments} + + +{ +\changestyle{align.tex} +} + + +\subsection{Inserts} +\TeX\ uses |vpack| to determine the natural height of inserted +material. In Hi\TeX, the function |vpack| will not always return +a |vlist_node| with a fixed height because the computation of the +height might fail. In the latter case, |vpack| will return a |vset_node| +or |vpack_node|. Therfore Hi\TeX\ will not use the |height| field of +a an |ins_node|. + +As a result we have the following changes: + + +{ +\changestyle{insert.tex} +} + + + + +\subsection{Implementing Hi\TeX\ Specific Primitives}\label{primitive} +Now we implement new \TeX\ primitives: +one to include images, a few more to define page teamplates, +and one to test whether the current instance of \TeX\ is +the new Hi\TeX. +To implement a primitive, we call the |primitive| function. +Since it needs the name of the new primitive as a \TeX\ string, +we need to add the strings to the \TeX\ string pool. + +Note that primitives are put into \TeX's memory when a \TeX\ format file is read. +So adding or changing the code below implies regenerating the format files. +To generate a format file run a command like + +{\tt\obeylines +hinitex +**plain \BS dump +} + +\noindent +Then find out where the \kpse\ library looks for format files +(for example by running + +{\tt\obeylines + kpsewhich latex.fmt +} + +\noindent +and then place the new format file in the same directory. + + +{ +\changestyle{primitive.tex} +} + + + + +\section{Hi\TeX} + +\subsection{Images} +The handling of images is an integral part of Hi\TeX. In +section~\secref{imageext} on page~\pageref{imageext} the {\tt image} +primitive was defined. It requires a filename for the image and +allows the specification, of width, height, stretch and shrink of an +image. If either width or height is not given, Hi\TeX\ tries to +extract this information from the image file itself calling the +function |hget_image_information| with the pointer |p| to the image +node as parameter. + +@<Hi\TeX\ routines@>= +void hget_image_information(pointer p) +{ char *fn; + FILE *f; + if (image_width(p)!=0 && image_height(p)!=0) return; + fn=dir[image_no(p)].file_name; + f=fopen(fn,"rb"); + if (f==NULL) QUIT("Unable to open image file %s.", fn); + MESSAGE("(%s",fn); + img_buf_size=0; + if (!get_BMP_info(f,fn,p)&&!get_PNG_info(f,fn,p)&&!get_JPG_info(f,fn,p)) + QUIT("Unable to obtain width and height information for image %s",fn); + fclose(f); + MESSAGE(" width= %fpt height= %fpt)",image_width(p)/(double)ONE,image_height(p)/(double)ONE); +} +@ + +When we have found the width and height of the stored image, we can +supplement the information given in the \TeX\ file. Occasionaly, the +image file will not specify the absolute dimensions of the image. In +this case, we can still compute the aspect ratio and supplement either +the width based on the height or vice versa. This is accomplished by +calling the |set_image_dimensions| function. It returns true on +success and false otherwise. + +@<Hi\TeX\ auxiliar routines@>= +static bool set_image_dimensions(pointer p, double w, double h, bool absolute) +{ if (image_width(p)!=0) + { double aspect=h/w; + image_height(p)=round(image_width(p)*aspect); + } + else if (image_height(p)!=0) + { double aspect=w/h; + image_width(p)=round(image_height(p)*aspect); + } + else + { if (!absolute) return false; + image_width(p)=round(unity*w); + image_height(p)=round(unity*h); + } + return true; +} +@ +We call the following routines with the image buffer partly filled +with the start of the image file. + +@<Hi\TeX\ auxiliar routines@>= +#define IMG_BUF_MAX 54 +#define IMG_HEAD_MAX 2 +static unsigned char img_buf[IMG_BUF_MAX]; +static size_t img_buf_size; +#define @[LittleEndian32(X)@] (img_buf[(X)]+(img_buf[(X)+1]<<8)+\ + (img_buf[(X)+2]<<16)+(img_buf[(X)+3]<<24)) + +#define @[BigEndian16(X)@] (img_buf[(X)+1]+(img_buf[(X)]<<8)) + +#define @[BigEndian32(X)@] (img_buf[(X)+3]+(img_buf[(X)+2]<<8)+\ + (img_buf[(X)+1]<<16)+(img_buf[(X)]<<24)) + +#define Match2(X,A,B) ((img_buf[(X)]==(A)) && (img_buf[(X)+1]==(B))) +#define Match4(X,A,B,C,D) (Match2(X,A,B)&&Match2((X)+2,C,D)) + +#define @[GET_IMG_BUF(X)@] \ +if (img_buf_size<X) \ + { size_t i=fread(img_buf+img_buf_size,1,(X)-img_buf_size,f); \ + if (i<0) QUIT("Unable to read image %s",fn); \ + else if (i==0) QUIT("Unable to read image header %s",fn); \ + else img_buf_size+=i; \ + } +@ + +\subsubsection{BMP} +We start with Windows Bitmaps. A Windows bitmap file usually has the extension {\tt .bmp} +but the better way to check for a Windows bitmap file ist to examine the first two byte +of the file: the ASCII codes for `B' and `M'. +Once we have verified the file type, we find the width and height of the bitmap in pixels +at offsets |0x12| and |0x16| stored as little-endian 32 bit integers. At offsets |0x26| and |0x2A|, +we find the horizontal and vertical resolution in pixel per meter stored in the same format. +This is sufficient to compute the true width and height of the image in scaled points. +If either the width or the height was given in the \TeX\ file, we just compute the aspect ratio +and compute the missing value. + +The Windows Bitmap format is easy to process but not very efficient. So the support for this +format in Hi\TeX\ is deprecated and will disappear. You should use one of the formats described next. + +@<Hi\TeX\ auxiliar routines@>= +static bool get_BMP_info(FILE *f, char *fn, pointer p) +{ double w,h; + double xppm,yppm; + GET_IMG_BUF(2); + if (!Match2(0,'B','M')) return false; + GET_IMG_BUF(0x2E); + w=(double)LittleEndian32(0x12); /*width in pixel*/ + h=(double)LittleEndian32(0x16); /*height in pixel*/ + xppm=(double)LittleEndian32(0x26); /* horizontal pixel per meter*/ + yppm=(double)LittleEndian32(0x2A); /* vertical pixel per meter*/ + return set_image_dimensions(p,(72.27*1000.0/25.4)*w/xppm,(72.27*1000.0/25.4)*h/yppm,true); +} +@ + +\subsubsection{PNG} +Now we repeat this process for image files in using the Portable Network Graphics\cite{png2nd} file +format. This file format is well suited to simple graphics that do not use color gradients. +These images usually have the extension {\tt .png} and start with an eight byte signature: +|0x89| followed by the ASCII Codes `P', `N', `G', followd by a carriage return (|0x0D| and line feed (|0x0A|), +an DOS end-of-file character (|0x1A|) and final line feed (|0x0A|). +After the signature follows a list of chunks. The first chunk is the image header chunk. +Each chunk starts with the size of the chunk stored as big-endian 32 bit integer, followed by the chunk name +stored as four ASCII codes followed by the chunk data and a CRC. The size as stored in the chunk +does not include the size itself, the name or the CRC. +The first chunk is the IHDR chunk. +The chunk data of the IHDR chunk starts with the width and the height of the image in pixels +stored as 32 bit big-endian integers. + +Finding the image resolution takes some more effort. The image resolution is stored in an optional chunk +named ``pHYs'' for the physical pixel dimensions. +All we know is that this chunk, if it exists, will appear after the IHDR +chunk and before the (required) IDAT chunk. The pHYs chunk contains two 32 bit big-endian integers, +giving the horizontal and vertical pixels per unit, and a one byte unit specifier, which is either 0 +for an undefined unit or 1 for the meter as unit. With an undefined unit only the aspect ratio +of the pixels anh hence the aspect ratio of the image can be determined. + + +@<Hi\TeX\ auxiliar routines@>= + +static bool get_PNG_info(FILE *f, char *fn, pointer p) +{ int pos, size; + double w,h; + double xppu,yppu; + int unit; + GET_IMG_BUF(24); + if (!Match4(0, 0x89, 'P', 'N', 'G') || + !Match4(4, 0x0D, 0x0A, 0x1A, 0x0A)) return false; + size=BigEndian32(8); + if (!Match4(12,'I', 'H', 'D', 'R')) return false; + w=(double)BigEndian32(16); + h=(double)BigEndian32(20); + pos=20+size; + while (true) + { if (fseek(f,pos,SEEK_SET)!=0) return false; + img_buf_size=0; + GET_IMG_BUF(17); + size=BigEndian32(0); + if (Match4(4,'p', 'H', 'Y', 's')) + { xppu =(double)BigEndian32(8); + yppu =(double)BigEndian32(12); + unit=img_buf[16]; + if (unit==0) + return set_image_dimensions(p,w/xppu,h/yppu,false); + else if (unit==1) + return set_image_dimensions(p,(72.27/0.0254)*w/xppu,(72.27/0.0254)*h/yppu,true); + else + return false; + } + else if (Match4(4,'I', 'D', 'A', 'T')) + return set_image_dimensions(p,w,h,false); + else + pos=pos+12+size; + } + return false; +} +@ + +\subsubsection{JPG} +For photographs, the JPEG File Interchange Format (JFIF)\cite{Ham92}\cite{JPEG93} is more appropriate. +JPEG files come with all sorts of file extensions like {\tt .jpg}, {\tt .jpeg}, or {\tt .jfif}. +We check the file siganture: it starts with the the SOI (Start of Image) marker |0xFF|, |0xD8| +followed by the JIFI-Tag. The JIFI-Tag starts with the segment marker APP0 (|0xFF|, |0xE0|) followed by the +2 byte segment size, followed by the ASCII codes `J', `F', `I', `F' followed by a zero byte. +Next is a two byte version number which we do not read. +Before the resolution proper there is a resolution unit indicator byte (0 = no units, +1 = dots per inch, 2 = dots per cm) and then comes the horizontal and vertical resolution both +as 16 Bit big-endian integers. +To find the actual width and height, we have to search for a start of frame marker (|0xFF|, |0xC0|+$n$ with $0\le n\le 15$). Which is followed by the 2 byte segment size, the 1 byte sample precission, the +2 byte height and the 2 byte width. + + +@<Hi\TeX\ auxiliar routines@>= + +static bool get_JPG_info(FILE *f, char *fn, pointer p) +{ int pos, size; + double w,h; + double xppu,yppu; + int unit; + GET_IMG_BUF(18); + + if (!Match4(0, 0xFF,0xD8, 0xFF, 0xE0)) return false; + size=BigEndian16(4); + if (!Match4(6,'J', 'F', 'I', 'F')) return false; + if (img_buf[10] != 0) return false; + unit=img_buf[13]; + xppu=(double)BigEndian16(14); + yppu=(double)BigEndian16(16); + pos=4+size; + while (true) + { if (fseek(f,pos,SEEK_SET)!=0) return false; + img_buf_size=0; + GET_IMG_BUF(10); + if (img_buf[0] != 0xFF) return false; /* Not the start of a segment */ + if ( (img_buf[1]&0xF0) == 0xC0) /* Start of Frame */ + { h =(double)BigEndian16(5); + w =(double)BigEndian16(7); + if (unit==0) + return set_image_dimensions(p,w/xppu,h/yppu,false); + else if (unit==1) + return set_image_dimensions(p,72.27*w/xppu,72.27*h/yppu,true); + else if (unit==2) + return set_image_dimensions(p,(72.27/2.54)*w/xppu,(72.27/2.54)*h/yppu,true); + else + return false; + } + else + { size= BigEndian16(2); + pos=pos+2+size; + } + } + return false; +} +@ + +\subsubsection{SVG} +There is still one image format missing: scalable vector graphics. +In the moment, I tend not to include a further image format into +the definition of the \HINT\ file format but instead use the +PostScript subset that is used for Type 1 fonts to encode +vector graphics. Any \HINT\ viewer must support Type 1 +PostScript fonts and hence it has already the necessary interpreter. +So it seems reasonable to put the burden of converting vector graphics +into a Type 1 PostScript font on the generator of \HINT\ files +and keep the \HINT\ viewer as small and simple as possible. + + +\subsection{Links, Labels, and Outlines} +The \HINT\ format knows about labels, links, and outlines. +When generating a short format \HINT\ file, links are part of +the content section, where as labels and outlines are found in +the definition section. Because labels are defined while +writing the content section, the writing of labels and outlines, which +reference the labels, must be postponed. For that reason, +we store information about labels and outlines in dynamic arrays, +and map labels, which are identified by a name or a number, +to their index using a dynamic hash table. + +We start with two functions that allocate new entries in the +dynamic arrays increasing their size if necessary. +@<Hi\TeX\ auxiliar routines@>= +static int next_label(void) +{ static int label_no=-1; + static int labels_allocated =0; + label_no++; + if (label_no>0xFFFF) + overflow("labels",0xFFFF); + if (label_no>=labels_allocated) + { if (labels_allocated==0) + { labels_allocated=32; ALLOCATE(labels,labels_allocated,label_t); } + else RESIZE(labels,labels_allocated,label_t); + } + max_ref[label_kind]=label_no; + return label_no; +} + +static int next_outline(void) +{ static int outlines_allocated =0; + static int outline_no=-1; + outline_no++; + if (outline_no>0xFFFF) + overflow("outlines",0xFFFF); + if (outline_no>=outlines_allocated) + { if (outlines_allocated==0) + { outlines_allocated=32; ALLOCATE(outlines,outlines_allocated,outline_t); } + else RESIZE(outlines,outlines_allocated,outline_t); + } + max_outline=outline_no; + return outline_no; +} +@ + +While processing the content nodes, access to the labels is provided either +by name or by number through a hash table. We store tabel entries in linked +lists starting with a reasonably sized table of pointers. This keeps +the fixed costs low and guards against overflow and rapidly increasing +inefficiency. We start with a function to insert a new entry into +the hash table. + +@<Hi\TeX\ auxiliar routines@>= +typedef struct hash_entry +{int num; char *nom; uint16_t n; struct hash_entry *next;} hash_entry_t; +#define LABEL_HASH 1009 /* MIX a prime number */ +static hash_entry_t *label_hash[LABEL_HASH]={NULL}; + +static int insert_hash(int h, int num, char *nom) +{ hash_entry_t *e; + ALLOCATE(e,1,hash_entry_t); + e->n= next_label(); + if (nom!=NULL) e->nom=strdup(nom); + else e->num=num; + e->next= label_hash[h]; + label_hash[h]=e; + if (e->nom!=NULL) + DBG(DBGLABEL,"Creating new label *%d: name='%s'\n",e->n,e->nom); + else + DBG(DBGLABEL,"Creating new label *%d: num=%d\n",e->n,e->num); + return e->n; +} +@ + +There are two cases: finding a label by name or by number. +We start with the simpler case where the number is given. +The process is straigth forward: + +@<Hi\TeX\ auxiliar routines@>= +static int find_label_by_number(int p) +{ unsigned int h=(unsigned int)p%LABEL_HASH; + hash_entry_t *e= label_hash[h]; + while (e!=NULL) + if (e->nom==NULL && e->num==p) return e->n; + else e=e->next; + return insert_hash(h,p,NULL); +} +@ + +To look up a label by its name as given by a token list, +we prepare ourselfs by implementing two functions: +one to extract the character codes from the token list +forming the ``name'' +and one to compute the hash value for a name. +The routine to find the label by name is then equivalent to the +routine we have just seen. Given a pointer |p| to +either a label, a link, or an outline node, the last function +returns the correct label reference. +Currently, we limit label names to at most 255 byte not counting the +zero byte. + +@<Hi\TeX\ auxiliar routines@>= +static char *tokens_to_name(pointer p) +{ static char s[256]; + int i=0; + bool skip_space=0; + while (i<255 && p!=0)@/ + { int m = info(p)/0400;@+ + int c = info(p)%0400; + if (m==spacer && ! skip_space) @/ + { s[i++]=' '; skip_space=true;@+} + else if ((m==letter || m==other_char) && ' '< c && c < 0x7F)@/ + {@+ s[i++]=c; skip_space=false;@+} + p=link(p); + } + s[i]=0; + return s; +} + +static unsigned int name_hash(char *s) +{ unsigned int h=0; + while (*s!=0) + h=(h<<2)+*(s++); + return h; +} + +static int find_label_by_name(pointer p) +{ char *s=tokens_to_name(link(p)); + unsigned int h=name_hash(s)%LABEL_HASH; + hash_entry_t *e= label_hash[h]; + while (e!=NULL) + if (e->nom!=NULL && strcmp(e->nom,s)==0) return e->n; + else e=e->next; + return insert_hash(h,0,s); +} +@ + +We combine both ways of finding a label reference in the following function: + +@<Hi\TeX\ auxiliar routines@>= +static int find_label(pointer p) +{@+ if (label_has_name(p)) return find_label_by_name(label_ptr(p)); + else return find_label_by_number(label_ptr(p)); +} +@ + +After these preparations, we can implement the functions needed +when labels, links, and outlines are delivered to the page builder. + +We start with looking at the labels: +When a labels is defined, the current position is recorded. +Further labels are linked together in order of descending positions, +to allow the efficient adjustment of label positions when +moving lists. + +@<Hi\TeX\ auxiliar routines@>= +static void new_label(pointer p) +{ int n=find_label(p); + if (n!=zero_label_no && labels[n].where!=LABEL_UNDEF) + { MESSAGE("WARNING: Ignoring duplicate definition of label "); + if (label_has_name(p)) MESSAGE("name %s\n",tokens_to_name(link(label_ptr(p)))); + else MESSAGE("num %d\n",label_ptr(p)); + } + else + { labels[n].where=label_where(p); + labels[n].pos=hpos-hstart; + labels[n].pos0=hpos0-hstart; + labels[n].next=first_label; + first_label=n; + DBG(DBGLABEL,"Defining label *%d: pos=0x%x\n",n,labels[n].pos); + } +} +@ + +When a link node is written to the output, we can check +that start links and end links properly match. + +@<Hi\TeX\ auxiliar routines@>= +static int last_link=-1; +static int new_start_link(pointer p) +{ int n=find_label(p); + if (last_link>=0) + fatal_error("Missing end link before start link"); + labels[n].used=true; + last_link=n; + DBG(DBGLABEL,"New link to label *%d\n",n); + return n; +} + +static int new_end_link(void) +{ int n; + if (last_link<0) + fatal_error("Missing start link before end link"); + n=last_link; + last_link=-1; + return n; +} +@ + +For outline nodes, we use the next two functions. +The node list representing the title can be an arbitrary +list in horizontal mode. +In general, the front end should be able to render such a +horizontal list, but at least it should be able to extract +the UTF8 characters codes and display those. + +@<Hi\TeX\ auxiliar routines@>= +static void new_outline(pointer p) +{ int r=find_label(p); + int m=next_outline(); + list_t l; + uint32_t pos; + pos=hpos-hstart; + l.k=list_kind; /* this eventually should be |text_kind| */ + hout_list_node(outline_ptr(p),pos,&l); + hset_outline(m,r,outline_depth(p),pos); + DBG(DBGLABEL,"New outline for label *%d\n",r); +} +@ + +One last function is needed, which better schould be in the {\tt htex.w} +file. It is called when the |outline_group| ends that was started +when scanning the {\tt\BS HINToutline} primitive. +@<Hi\TeX\ routines@>= +void hfinish_outline_group(void) +{ pointer s=link(head); + unsave(); + pop_nest(); + outline_ptr(tail)=s; +} +@ + +\subsection{The New Page Builder}\label{buildpage} +Here is the new |build_page| routine of Hi\TeX: + +@<Hi\TeX\ routines@>= +void build_page(void) +{ static bool initial=true; + if(link(contrib_head)==null||output_active)return; + do + { pointer p= link(contrib_head); + pointer q=null; /* for output nodes */ + pointer *t; /*the tail of the output nodes*/ + @<Record the bottom mark@>@; + @<Suppress empty pages if requested@>@; + link(contrib_head)= link(p);link(p)= null; + if (link(contrib_head)==null) + { if(nest_ptr==0) tail= contrib_head; + else contrib_tail= contrib_head; + } + update_last_values(p); + @<Freeze the page specs if called for@>@; + page_goal=0x3fffffff; /* maximum dimension */ + t=collect_output(&p,&q); + if (p!=null) + { hpos0=hpos; hout_node(p); } +recycle_p: + flush_node_list(p); + if (q!=null) + @<Fire up the output routine for |q|@>@; + } while(link(contrib_head)!=null); + DBG(DBGBUFFER,"after build page dyn_used= %d\n", dyn_used); +} +@ + +@<Freeze the page specs if called for@>= +if (page_contents<box_there) +{ switch(type(p)) + { case whatsit_node: + if (subtype(p)==baseline_node) goto recycle_p; + else if (subtype(p)!=hset_node && subtype(p)!=vset_node && + subtype(p)!=hpack_node && subtype(p)!=vpack_node && + subtype(p)!=graf_node && subtype(p)!=disp_node && + subtype(p)!=image_node && subtype(p)!=align_node) + break; /* else fall through */ + case hlist_node: case vlist_node: case rule_node: + if (page_contents==empty) + { freeze_page_specs(box_there); + hfix_defaults(); + } + else page_contents=box_there; + break; + case ins_node: + if (page_contents==empty) + { freeze_page_specs(inserts_only); + hfix_defaults(); + } + break; + case kern_node: + case penalty_node: + case glue_node: goto recycle_p; + default: + break; + } +} +@ + +Users of \TeX\ often force the generation of empty pages for example to start +a new chapter on a right hand page with an odd page number. +This makes sense for a printed book but not for a screen reader where +there are no page numbers nor right or left hand pages. +Using a screen reader, empty pages are just annoying. +The common way to achive an empty page is the use of {\tt \BS eject} +followed by a an empty box, a fill glue, and another {\tt \BS eject}. + +The following code tries to detect such a sequence of nodes and will eliminate +them if requested. To do so, we delay the output of nodes after +an eject penalty until either something gets printed on the page or +another eject penalty comes along. To override the delayed output, +a penalty less or equal to a double |eject_penalty| can be used. +The function |its_all_over| (see section~\secref{itsallover}) +is an example for such a use. + + +@<Suppress empty pages if requested@>= +if (option_no_empty_page && + ((type(p)==penalty_node && + penalty(p)<=eject_penalty && penalty(p)>2*(eject_penalty)) || + (page_contents==empty && !is_visible(p)))) +{ pointer q= link(p); + while (true) + { if (q==null) return; + else if (is_visible(q)) break; + else if (type(q)==penalty_node && penalty(q)<=eject_penalty) + { while (p!=q) + { pointer r=p; + DBG(DBGPAGE,"Eliminating node (%d,%d)\n", + type(p), type(p)==penalty_node?penalty(p):subtype(p)); + p=link(p); + link(r)=null; + flush_node_list(r); + } + link(contrib_head)= p; + DBG(DBGPAGE,"Eliminating empty page done\n"); + if (penalty(q)<=2*(eject_penalty)) break; + } + q=link(q); + } +} +@ +It remains to test a node for visibility. This is a quick (and dirty) test +because the test will not look inside boxes; it simply tests whether +the list pointer is |null|. We consider an |open_node|, |write_node|, +|close_node|, |label_node|, or |outline_node| a as visible, +because deleting them could cause unwanted +side effects. Possibly it would be better to regard them as invisible, +but still pass them on to the rest of the output routine. + +@<Hi\TeX\ auxiliar routines@>= +static bool is_visible(pointer p) +{ switch (type(p)) + { case penalty_node: + case kern_node: + case glue_node: + case mark_node: + return false; + case ins_node: + return ins_ptr(p)!=null; + case adjust_node: + return adjust_ptr(p)!=null; + case hlist_node: + case vlist_node: + return list_ptr(p)!=null; + case whatsit_node: + if (subtype(p)==image_node || subtype(p)==align_node || subtype(p)==disp_node || + subtype(p)==open_node ||subtype(p)==write_node ||subtype(p)==close_node || + subtype(p)==label_node || subtype(p)==outline_node ) + return true; + else if (subtype(p)==hset_node || subtype(p)==vset_node || + subtype(p)==hpack_node || subtype(p)==vpack_node) + return list_ptr(p)!=null; + else if (subtype(p)==graf_node) + return graf_list(p)!=null; + else + return false; + default: return true; + } +} +@ + +An important feature of the new routine is the call to +|hfix_defaults|. It occurs when the first ``visible mark'' is placed +on the page. At that point we record the current values of \TeX's +parameters which we will use to generate the definition section of the +\HINT\ file. It is still possible to specify alternative values for +these parameters by using parameter lists but only at an additional +cost in space and time. + +Furthermore, this is the point where we freeze the definition of +|hsize| and |vsize|. The current values will be regarded as the sizes +as recommended by the author. + +From then on |hsize| and |vsize| are replaced by the equivalent +extended dimensions and any attempt to modify them on the global level +will be ignored. |hhsize| and |hvsize| will contain the sizes that a +regular \TeX\ engine would use. + +We also compute the total page size from the page template defined +last. + + +@<Compute the page size@>= +{ pointer p; + p=link(setpage_head); + if (p==null) + { scaled margin; + if (hhsize<hvsize) margin=hhsize; else margin=hvsize; + margin = margin/6 -6*unity; + if (margin<0) margin=0; + page_h=hhsize+2*margin; + page_v=hvsize+2*margin; + } + else + { pointer x; + x=setpage_height(p); + page_v=xdimen_width(x) + +round(((double)xdimen_hfactor(x)*hhsize+(double)xdimen_vfactor(x)*hvsize)/unity); + x=setpage_width(p); + page_h=xdimen_width(x) + +round(((double)xdimen_hfactor(x)*hhsize+(double)xdimen_vfactor(x)*hvsize)/unity); + } +} +@ + +@<Hi\TeX\ variables@>= +static scaled page_h, page_v; +@ + +@<Switch |hsize| and |vsize| to extended dimensions@>= + hsize=0; vsize=0; + dimen_par_hfactor(hsize_code)= unity; + dimen_par_vfactor(vsize_code)= unity; +@ + +There is one point where we can not simpy forego the +output routine: \.{\\write} commands. Unless the \.{\\write} is +decorated with an \.{\\immediate}, the whatsit node generated from it +will lay dormant in the contribution list and then the page until +the output routine passes it inside the finished page to the |ship_out| +routine where it will come to life and write its token list out. +The whatsit nodes from \.{\\openout} and \.{\\closeout} commands +behave similary. + +It is not possible to ignore the output routine +because the output routine may change the environment in which the +token list of a \.{\\write} will be expanded. +For example \LaTeX\ redefines \.{\\protect} to be \.{\\noexpand}. +As a consequence we have to implement a simplified version +of \TeX's usual process to fire up the output routine. + +The |collect_output| routine takes a node list |p|, +removes the output nodes and appends them to |q|, with |q| +always pointing to the tail pointer. + +@<Hi\TeX\ auxiliar routines@>= +static pointer *collect_output(pointer *p, pointer *q) +{ while (*p!=null) + { @<Collect output nodes from |*p|@>@; + p=&(link(*p)); + } + return q; +} +@ + +\TeX\ does not permit output nodes in leaders, so we dont check them; +further we do not check the pre- and post-break lists of +discretionary breaks. + +@<Collect output nodes from |*p|@>= +if (!is_char_node(*p)) +{ pointer r=*p; + switch (type(r)) + { case whatsit_node: + switch (subtype(r)) + { case open_node: case write_node: case close_node: + { *p=link(r); link(r)=null; *q=r; q=&(link(r)); + if (*p==null) return q; + } + break; + case graf_node: q=collect_output(&graf_list(r),q); + break; + case disp_node: + if (display_left(r)) q=collect_output(&display_eqno(r),q); + q=collect_output(&display_formula(r),q); + if (!display_left(r)) q=collect_output(&display_eqno(r),q); + break; + case hset_node: case vset_node: case hpack_node: case vpack_node: + q=collect_output(&list_ptr(r),q); + break; + case align_node: + q=collect_output(&align_list(r),q); + break; + default: break; + } + break; + case hlist_node: case vlist_node: + q=collect_output(&list_ptr(r),q); + break; + case ins_node: + q=collect_output(&ins_ptr(r),q); + break; + case adjust_node: + q=collect_output(&adjust_ptr(r),q); + break; + default: break; + } +} +@ + + + +@<Fire up the output routine for |q|@>= +{ pointer r=new_null_box();type(r)=vlist_node; + subtype(r)=0;shift_amount(r)=0;height(r)=hvsize; + list_ptr(r)=q; + *t=new_glue(ss_glue); + flush_node_list(box(255)); /* just in case \dots */ + box(255)=r; + if (output_routine!=null) + {@+output_active=true; + if (bot_mark!=null) + {@+if (top_mark!=null) delete_token_ref(top_mark); + top_mark=bot_mark;add_token_ref(top_mark); + if (first_mark!=null) delete_token_ref(first_mark); + first_mark=bot_mark;add_token_ref(first_mark); + } + push_nest();mode=-vmode;prev_depth=ignore_depth;mode_line=-line; + begin_token_list(output_routine, output_text); + new_save_level(output_group);normal_paragraph(); + scan_left_brace(); + return; + } + else + { + ship_out(box(255)); box(255)=null; + } +} +@ + +The |ship_out| routine just calls |execute_output|. +Because the output routine might have added plenty +of decorations around the list of output nodes, +we have to find them again. + +@<Hi\TeX\ routines@>= +void execute_output(pointer p) +{@+while (p!=null) + { @<Execute output nodes from |p|@>@; + p=link(p); + } +} +@ + +@<Execute output nodes from |p|@>= +if (!is_char_node(p)) + switch (type(p)) + { case whatsit_node: + switch (subtype(p)) + { case open_node: case write_node: case close_node: + out_what(p); + break; + case graf_node: execute_output(graf_list(p)); + break; + case disp_node: + if (display_left(p)) execute_output(display_eqno(p)); + execute_output(display_formula(p)); + if (!display_left(p)) execute_output(display_eqno(p)); + break; + case hset_node: case vset_node: case hpack_node: case vpack_node: + execute_output(list_ptr(p)); + break; + case align_node: + execute_output(align_list(p)); + break; + default: break; + } + break; + case hlist_node: case vlist_node: + execute_output(list_ptr(p)); + break; + case ins_node: + execute_output(ins_ptr(p)); + break; + case adjust_node: + execute_output(adjust_ptr(p)); + break; + default: break; + } +@ + +Invoking the user's output routine is a risky endeavor +if marks are not initialized properly. In our case +we will have always |top_mark| equal to |first_mark| and +|bot_mark|. + +@<Record the bottom mark@>= +if (type(p)==mark_node) +{ if (bot_mark!=null) delete_token_ref(bot_mark); + bot_mark=mark_ptr(p);add_token_ref(bot_mark); +} +@ + + +\subsection{Replacing {\tt hpack} and {\tt vpack}} + + +@<Hi\TeX\ routines@>= + +pointer hpack(pointer p,scaled w, scaled hf, scaled vf, small_number m) +{ + pointer r; /*the box node that will be returned*/ + pointer prev_p; /*trails behind |p|*/ + scaled h,d,x; /*height, depth, and natural width*/ + scaled s; /*shift amount*/ + pointer g; /*points to a glue specification*/ + glue_ord sto, sho; /*order of infinity*/ + internal_font_number f; /*the font in a |char_node|*/ + four_quarters i; /*font information about a |char_node|*/ + eight_bits hd; /*height and depth indices for a character*/ + last_badness= 0;r= get_node(box_node_size);type(r)= hlist_node; + subtype(r)= min_quarterword;shift_amount(r)= 0; + prev_p= r+list_offset;link(prev_p)= p; + h= 0; d= 0; x= 0; + total_stretch[normal]= 0;total_shrink[normal]= 0; + total_stretch[fil]= 0;total_shrink[fil]= 0; + total_stretch[fill]= 0;total_shrink[fill]= 0; + total_stretch[filll]= 0;total_shrink[filll]= 0; + while(p!=null) + { + reswitch: + while(is_char_node(p)) + { f= font(p);i= char_info(f, character(p));hd= height_depth(i); + x= x+char_width(f, i); + s= char_height(f, hd);if (s> h)h= s; + s= char_depth(f, hd);if (s> d)d= s; + p= link(p); + } + if (p!=null) + { switch(type(p)){ + case hlist_node:case vlist_node:case rule_node:case unset_node: + { x= x+width(p); + if (type(p)>=rule_node)s= 0;else s= shift_amount(p); + if (height(p)-s> h)h= height(p)-s; + if (depth(p)+s> d)d= depth(p)+s; + } + break; + case ins_node:case mark_node:case adjust_node:if (adjust_tail!=null) + { while(link(prev_p)!=p)prev_p= link(prev_p); + if (type(p)==adjust_node) + { link(adjust_tail)= adjust_ptr(p); + while(link(adjust_tail)!=null)adjust_tail= link(adjust_tail); + p= link(p);free_node(link(prev_p),small_node_size); + } + else + { link(adjust_tail)= p;adjust_tail= p;p= link(p); + } + link(prev_p)= p;p= prev_p; + } + break; + case whatsit_node: + if (subtype(p)==graf_node) + goto repack; + else if (subtype(p)==disp_node ) + goto repack; + else if (subtype(p)==vpack_node ) + goto repack; + else if (subtype(p)==hpack_node ) + goto repack; + else if (subtype(p)==hset_node ) + goto repack; + else if (subtype(p)==vset_node ) + goto repack; + else if (subtype(p)==stream_node ) + goto repack; + else if (subtype(p)==image_node) + { glue_ord o; + if (image_height(p)> h) h= image_height(p); + x= x+image_width(p); + o= image_stretch_order(p);total_stretch[o]= total_stretch[o]+image_stretch(p); + o= image_shrink_order(p);total_shrink[o]= total_shrink[o]+image_shrink(p); + } + break; + break; + case glue_node: + { glue_ord o; + g= glue_ptr(p);x= x+width(g); + o= stretch_order(g);total_stretch[o]= total_stretch[o]+stretch(g); + o= shrink_order(g);total_shrink[o]= total_shrink[o]+shrink(g); + if (subtype(p)>=a_leaders) + { g= leader_ptr(p); + if (height(g)> h)h= height(g); + if (depth(g)> d)d= depth(g); + } + } + break; + case kern_node:case math_node:x= x+width(p);break; + case ligature_node: + { mem[lig_trick]= mem[lig_char(p)];link(lig_trick)= link(p); + p= lig_trick;goto reswitch; + } + default:do_nothing; + } + p= link(p); + } + } + if (adjust_tail!=null) link(adjust_tail)= null; + height(r)= h;depth(r)= d; + if (total_stretch[filll]!=0)sto= filll; + else if (total_stretch[fill]!=0)sto= fill; + else if (total_stretch[fil]!=0)sto= fil; + else sto= normal; + + if (total_shrink[filll]!=0)sho= filll; + else if (total_shrink[fill]!=0)sho= fill; + else if (total_shrink[fil]!=0)sho= fil; + else sho= normal; + + if (hf!=0 || vf!=0 ) /* convert to a hset node */ + { pointer q; + q=new_set_node(); + subtype(q)=hset_node; + height(q)=h; + depth(q)=d; + width(q)=x; /* the natural width */ + shift_amount(q)=shift_amount(r); + list_ptr(q)=list_ptr(r); + list_ptr(r)=null; + free_node(r, box_node_size); + if (m==exactly) + set_extent(q)=new_xdimen(w,hf,vf); + else + set_extent(q)=new_xdimen(x+w,hf,vf); + set_stretch_order(q)=sto; + set_shrink_order(q)=sho; + set_stretch(q)=total_stretch[sto]; + set_shrink(q)=total_shrink[sho]; + return q; + } + + + + + if (m==additional) w= x+w; + width(r)= w;x= w-x; /*now |x| is the excess to be made up*/ + + if (x==0) + { glue_sign(r)= normal; glue_order(r)= normal; + set_glue_ratio_zero(glue_set(r)); + goto end; + } + else if (x> 0) + { + glue_order(r)= sto;glue_sign(r)= stretching; + if (total_stretch[sto]!=0)glue_set(r)= unfloat(x/(double)total_stretch[sto]); + else + { glue_sign(r)= normal; + set_glue_ratio_zero(glue_set(r)); + } + if (sto==normal) + { if (list_ptr(r)!=null) + { last_badness= badness(x,total_stretch[normal]); + if (last_badness> hbadness) + { print_ln(); + if (last_badness> 100) + print_nl("Underfull");else print_nl("Loose"); + print(" \\hbox (badness ");print_int(last_badness); + goto common_ending; + } + } + } + goto end; + } + else + { + glue_order(r)= sho;glue_sign(r)= shrinking; + if (total_shrink[sho]!=0) + glue_set(r)= unfloat((-x)/(double)total_shrink[sho]); + else + { glue_sign(r)= normal; + set_glue_ratio_zero(glue_set(r)); + } + if ((total_shrink[sho]<-x)&&(sho==normal)&&(list_ptr(r)!=null)) + { last_badness= 1000000; + set_glue_ratio_one(glue_set(r)); + if ((-x-total_shrink[normal]> hfuzz)||(hbadness<100)) + { if ((overfull_rule> 0)&&(-x-total_shrink[normal]> hfuzz)) + { while(link(prev_p)!=null)prev_p= link(prev_p); + link(prev_p)= new_rule(); + width(link(prev_p))= overfull_rule; + } + print_ln();print_nl("Overfull \\hbox ("); + print_scaled(-x-total_shrink[normal]);print("pt too wide"); + goto common_ending; + } + } + else if (sho==normal) + { if (list_ptr(r)!=null) + { last_badness= badness(-x,total_shrink[normal]); + if (last_badness> hbadness) + { print_ln();print_nl("Tight \\hbox (badness ");print_int(last_badness); + goto common_ending; + } + } + } + goto end; + } + common_ending: + if (pack_begin_line!=0) + { if (pack_begin_line> 0)print(") in paragraph at lines "); + else print(") in alignment at lines "); + print_int(abs(pack_begin_line)); + print("--"); + } + else print(") detected at line "); + print_int(line); + print_ln(); + font_in_short_display= null_font;short_display(list_ptr(r));print_ln(); + begin_diagnostic();show_box(r);end_diagnostic(true); + end:return r; + + +repack: + { /* convert the box to a |hpack_node| */ + pointer q; + q=new_pack_node(); + height(q)=h; + depth(q)=d; + width(q)=x; + subtype(q)=hpack_node; + list_ptr(q)=list_ptr(r); + list_ptr(r)=null; + free_node(r, box_node_size); + pack_limit(q)=max_dimen; /* no limit, not used */ + pack_m(q)=m; + pack_extent(q)=new_xdimen(w,hf,vf); + return q; + } +} + +@ + +@<Hi\TeX\ routines@>= +pointer vpackage(pointer p, scaled h, scaled hf, scaled vf, small_number m, scaled l) +{ pointer r; /*the box node that will be returned*/ + scaled w,d,x; /*width, depth, and natural height*/ + scaled s=0; /*shift amount*/ + pointer g; /*points to a glue specification*/ + glue_ord sho, sto; /*order of infinity*/ + last_badness= 0; r= get_node(box_node_size); type(r)= vlist_node; + subtype(r)= min_quarterword; shift_amount(r)= 0; + list_ptr(r)= p; + w= 0; + d= 0;x= 0; + total_stretch[normal]= 0;total_shrink[normal]= 0; + total_stretch[fil]= 0;total_shrink[fil]= 0; + total_stretch[fill]= 0;total_shrink[fill]= 0; + total_stretch[filll]= 0;total_shrink[filll]= 0; + while(p!=null) + { if (is_char_node(p)) + confusion("vpack"); + else + switch(type(p)) + { case hlist_node:case vlist_node:case rule_node:case unset_node: + x= x+d+height(p);d= depth(p); + if (type(p)>=rule_node) s= 0; + else s= shift_amount(p); + if (width(p)+s> w) w= width(p)+s; + break; + case whatsit_node: + if (subtype(p)==graf_node) + goto repack; + else if (subtype(p)==disp_node ) + goto repack; + else if (subtype(p)==vpack_node ) + goto repack; + else if (subtype(p)==hpack_node ) + goto repack; + else if (subtype(p)==hset_node ) + goto repack; + else if (subtype(p)==vset_node ) + goto repack; + else if (subtype(p)==stream_node ) + goto repack; + else if (subtype(p)==image_node) + { glue_ord o; + if (image_width(p)> w) w= image_width(p); + x= x+d+image_height(p);d=0; + o= image_stretch_order(p);total_stretch[o]= total_stretch[o]+image_stretch(p); + o= image_shrink_order(p);total_shrink[o]= total_shrink[o]+image_shrink(p); + } + break; + case glue_node: + { glue_ord o; + x= x+d;d= 0; + g= glue_ptr(p);x= x+width(g); + o= stretch_order(g); total_stretch[o]= total_stretch[o]+stretch(g); + o= shrink_order(g); total_shrink[o]= total_shrink[o]+shrink(g); + if (subtype(p)>=a_leaders) + { g= leader_ptr(p); + if (width(g)> w) w= width(g); + } + } + break; + case kern_node: + x= x+d+width(p);d= 0; + break; + default:do_nothing; + } + p= link(p); + } + width(r)= w; + + + if (total_stretch[filll]!=0) sto= filll; + else if (total_stretch[fill]!=0) sto= fill; + else if (total_stretch[fil]!=0) sto= fil; + else sto= normal; + + if (total_shrink[filll]!=0) sho= filll; + else if (total_shrink[fill]!=0) sho= fill; + else if (total_shrink[fil]!=0) sho= fil; + else sho= normal; + + if (hf!=0 || vf!=0) /* convert to a vset node */ + { pointer q; + q=new_set_node(); + subtype(q)=vset_node; + width(q)=w; + if (d> l) + { x= x+d-l;depth(r)= l; + } + else depth(r)= d; + height(q)=x; + depth(q)=d; + shift_amount(q)=shift_amount(r); + list_ptr(q)=list_ptr(r); + list_ptr(r)=null; + free_node(r, box_node_size); + if (m==exactly) + set_extent(q)=new_xdimen(h,hf,vf); + else + set_extent(q)=new_xdimen(x+h,hf,vf); + set_stretch_order(q)=sto; + set_shrink_order(q)=sho; + set_stretch(q)=total_stretch[sto]; + set_shrink(q)=total_shrink[sho]; + return q; + } + + if (d> l) + { x= x+d-l;depth(r)= l; + } + else depth(r)= d; + if (m==additional) + h= x+h; + height(r)= h; x= h-x; /*now |x| is the excess to be made up*/ +if (x==0) + { glue_sign(r)= normal; glue_order(r)= normal; + set_glue_ratio_zero(glue_set(r)); + goto end; + } + else if (x> 0) + { glue_order(r)= sto;glue_sign(r)= stretching; + if (total_stretch[sto]!=0)glue_set(r)= unfloat(x/(double)total_stretch[sto]); + else + { glue_sign(r)= normal; + set_glue_ratio_zero(glue_set(r)); + } + if (sto==normal) + { if (list_ptr(r)!=null) + { last_badness= badness(x,total_stretch[normal]); + if (last_badness> vbadness) + { print_ln(); + if (last_badness> 100)print_nl("Underfull");else print_nl("Loose"); + print(" \\vbox (badness ");print_int(last_badness); + goto common_ending; + } + } + } + goto end; + } + else /* if (x<0) */ + { + glue_order(r)= sho;glue_sign(r)= shrinking; + if (total_shrink[sho]!=0)glue_set(r)= unfloat((-x)/(double)total_shrink[sho]); + else + { glue_sign(r)= normal; + set_glue_ratio_zero(glue_set(r)); + } + if ((total_shrink[sho]<-x)&&(sho==normal)&&(list_ptr(r)!=null)) + { last_badness= 1000000; + set_glue_ratio_one(glue_set(r)); + if ((-x-total_shrink[normal]> vfuzz)||(vbadness<100)) + { print_ln();print_nl("Overfull \\vbox ("); + print_scaled(-x-total_shrink[normal]);print("pt too high"); + goto common_ending; + } + } + else if (sho==normal) + { if (list_ptr(r)!=null) + { last_badness= badness(-x,total_shrink[normal]); + if (last_badness> vbadness) + { print_ln();print_nl("Tight \\vbox (badness ");print_int(last_badness); + goto common_ending; + } + } + } + goto end; + } + + + common_ending: + if (pack_begin_line!=0) + { print(") in alignment at lines "); + print_int(abs(pack_begin_line)); + print("--"); + } + else + print(") detected at line "); + print_int(line); + print_ln(); + + begin_diagnostic();show_box(r);end_diagnostic(true); + end: + return r; + + +repack: + { /* convert the box to a |vpack_node| */ + pointer q; + q=new_pack_node(); + subtype(q)=vpack_node; + height(q)=x; + depth(q)=d; + width(q)=w; + list_ptr(q)=list_ptr(r); + list_ptr(r)=null; + free_node(r, box_node_size); + pack_limit(q)=l; + pack_m(q)=m; + pack_extent(q)=new_xdimen(h,hf,vf); + return q; + } +} + +@ + +\subsection{Streams} +\HINT\ stream numbers start at 0 for the main text and continue +upwards. \TeX, on the other hand, numbers insertions starting with +{\tt box255} for the main text and continues downwards. Some mapping is +needed, and we use the array |insert2stream| to map \TeX's insert +numbers to \HINT\ stream numbers. +The predefined stream for the main content has stream number 0. + +@<Hi\TeX\ variables@>= +int insert2stream[0x100]={0}; +@ + +The following function returns the stream number for a given insert number $i$ +with $255>|i|\ge 0$. A new stream number is allocated if necessary. +Note that no overflow test is necessary since \TeX\ allocates less +than 233 inserts. +The initial value of |max_ref[stream_kind]| is 0 and therefore +stream number 0, reserved for the main content +is never allocated. Stream definitions might also be loaded +as part of a format file. Then the maximum stream number ist stored in |max_stream|. +So if we do not find a stream number +in the |insert2stream| array, we scan the stream definitions +once and cache the associations found there. + +@<Hi\TeX\ routines@>= +int hget_stream_no(int i) +{ static bool init=false; + int s; + if (i==0) return 0; + s=insert2stream[i]; + if (s!=0) return s; + if (!init) + { pointer t,s; + for (t=link(setpage_head); t!=null; t=link(t)) + for(s=setpage_streams(t); s!=null; s=link(s)) + insert2stream[setstream_insertion(s)]=setstream_number(s); + max_ref[stream_kind]=max_stream; + init=true; + } + s=insert2stream[i]; + if (s==0) + s=insert2stream[i]=max_ref[stream_kind]=++max_stream; + return s; +} +@ + +\subsection{Stream Definitions} + +A stream definition is stored as a whatsit node with subtype |setstream_node| as +defined in section~\secref{whatsit}. +Given a pointer |p| to such a node, here are the macros used to access the data stored there: +\itemize +\item |setstream_number(p)| the \HINT\ stream number $n$. +\item |setstream_insertion(p)| the corresponding \TeX\ insertion number $i$. +\item |setstream_max(p)| the maximum height $x$: This extended dimension is the maximum size + per page for this insertion. +\item |setstream_mag(p)| the magnification factor $f$: + Inserting a box of height $h$ will contribute $h*f/1000$ + to the main page. +\item |setstream_prefered(p)| the prefered stream $p$: + If $p\ge0$ we move the insert to stream $p$ if possible. +\item |setstream_next(p)| the next stream $n$: + If $n\ge0$ we move the insert to stream $n$ if it can not be + accomodated otherwise. +\item |setstream_ratio(p)| the split ratio $r$: + If $r>0$ split the final contribution of this streams between + stream $p$ and $n$ in the ratio $r/1000$ for $p$ and $1-r/1000$ for $n$ + before contributing streams $p$ and $r$ to the page. +\item |setstream_before(p)| the ``before'' list $b$: + For a nonempty stream the material that is added before the stream content. +\item |setstream_after(p)| the ``after'' list $a$: + For a nonempty stream, material that is added after the stream conten. +\item |setstream_topskip(p)| the top skip glue $t$: This glue is inserted between + the $b$ list and the stream content and ajusted for the height for the first box + of the stream content. +\item |setstream_width(p)| the width $w$: + This extended dimension is the width used for example + to break paragraphs in the stream content into lines. +\item |setstream_height(p)| a glue specification $h$ reflecting the total height, + strechability and shrinkability of the material in lists $a$ and $b$. +\enditemize + +Currently Hi\TeX\ handles only normal streams. First or last streams will come later. + +The stream definition nodes are created and initialized with the following function: +@<Hi\TeX\ routines@>= +pointer new_setstream_node(uint8_t n) +{ pointer p=get_node(setstream_node_size); + type(p)=whatsit_node;subtype(p)=setstream_node; + setstream_insertion(p)=n; + setstream_number(p)=hget_stream_no(n); + setstream_mag(p)=1000; + setstream_prefered(p)=255; + setstream_next(p)=255; + setstream_ratio(p)=0; + setstream_max(p)=new_xdimen(0,0,ONE); + setstream_width(p)=new_xdimen(0,ONE,0); + setstream_topskip(p)=zero_glue; add_glue_ref(zero_glue); + setstream_height(p)=zero_glue; add_glue_ref(zero_glue); + setstream_before(p)=null; + setstream_after(p)=null; + + return p; +} +@ + + +The prefered stream, the next stream, and the split ratio are scanned as part of the +{\tt \BS setstream} primitive as described in section~\secref{primitive}. +When \TeX\ finds the right brace that terminates the stream definition, +it calls |handle_right_brace|. Then it is time to obtain the remaining parts of the +stream definition. +For insertion class $i$, +we can extract the maximum height $x$ of the insertions from +the corresponding {\tt dimen$i$} register +the magnification factor $f$ from the {\tt count$i$} register, +and the total height $h$ from the {\tt skip$i$} register. +The width $w$ is taken from {\tt \BS hsize} and the +topskip $t$ from {\tt \BS topskip}. + +@<Hi\TeX\ routines@>= +void hfinish_stream_group(void) +{ pointer s; + end_graf(); + s=hget_current_stream(); + if (s!=null) + { pointer t; + uint8_t i; + i= setstream_insertion(s); + setstream_mag(s)=count(i); + setstream_width(s)=new_xdimen(dimen_par(hsize_code), + dimen_par_hfactor(hsize_code),dimen_par_vfactor(hsize_code)); + t=zero_glue;add_glue_ref(t);delete_glue_ref(setstream_topskip(s)); setstream_topskip(s)=t; + t=skip(i);add_glue_ref(t);delete_glue_ref(setstream_height(s)); setstream_height(s)=t; + setstream_max(s)=new_xdimen(dimen(i), + dimen_hfactor(i),dimen_vfactor(i)); + } + unsave(); + flush_node_list(link(head)); + pop_nest(); +} +@ + +The before list $b$ and the after list $a$ are defined using the +{\tt \BS before} and {\tt \BS after} primitives. When the corresponding list +has ended with a right brace, \TeX\ calls |handle_right_brace| and we can store +the lists. + +@<Hi\TeX\ routines@>= +void hfinish_stream_before_group(void) +{ pointer s; + end_graf(); + s=hget_current_stream(); + if (s!=null) + setstream_before(s)=link(head); + unsave(); + pop_nest(); +} + +void hfinish_stream_after_group(void) +{ pointer s; + end_graf(); + s=hget_current_stream(); + if (s!=null) + setstream_after(s)=link(head); + unsave(); + pop_nest(); +} +@ + +\subsection{Page Template Definitions} + +The data describing a page template is stored in a whatsit node with subtype +|setpage_node| as defined insection~\secref{whatsit}. +Given a pointer |p| to such a node, here are the macros used to access the data stored there: +\itemize +\item |setpage_name(p)|: The name of the page template + can be used in the user interface of a \HINT\ viewer. +\item |setpage_number(p)|: The number of the page template that is used in the \HINT\ + file to reference this page template. +\item |setpage_id(p)|: The number of the page template that is used in \TeX\ + to reference this page template. +\item |setpage_priority(p)|: The priority helps in selecting a page template. +\item |setpage_topskip(p)|: The topskip glue is added at the top of a page and + adjusted by the height of the first bos on the page. +\item |setpage_height(p)|: The height of the full page including the margins. +\item |setpage_width(p)|: The width of the full page including the margins. +\item |setpage_depth(p)|: The maximum depth of the page content. If the last box is deeper +than this maximum, the difference is subtracted from the height of the page body. +\item |setpage_list(p)|: The list that defines the page template. After the page builder +has completed a page this list is scanned and page body and nonempty streams +are added at the corresponding insertion points. +\item |setpage_streams(p)|: The list of stream definitions that +belong to this page template. +\enditemize + +To allow \TeX\ to use arbitrary numbers between 1 and 255 for the page templates +while in \HINT\ the numbers of page templates are best consecutive +from 1 to |max_ref[page_kind]==max_page|, we let \TeX\ assign an id and generate +the template number. Because templates might be in format files, the variable +|max_page| will hold the true number. + +The function |new_setpage_node| is called with the page template id +$0<|i|<256$ and a string number for the name |n|. +It allocates and initializes a node if necessary and moves it to the front of the +list of templates. + +@<Hi\TeX\ routines@>= +pointer new_setpage_node(uint8_t i, str_number n) +{ pointer p, prev_p; + prev_p=setpage_head; + for (p=link(prev_p); p!=null; prev_p=p,p=link(p)) + if (setpage_id(p)==i) break; + if (p==null) + @<allocate a new |setpage_node| |p|@>@; + else + link(prev_p)=link(p); + link(p)=link(setpage_head); + link(setpage_head)=p; + return p; +} +@ + +@<allocate a new |setpage_node| |p|@>= +{ p=get_node(setpage_node_size);type(p)=whatsit_node;subtype(p)=setpage_node; + setpage_number(p)=max_ref[page_kind]=++max_page; + setpage_id(p)=i; + setpage_name(p)=n; + setpage_priority(p)=1; + setpage_topskip(p)=zero_glue; add_glue_ref(zero_glue); + setpage_height(p)=new_xdimen(0,0,ONE); + setpage_width(p)=new_xdimen(0,ONE,0); + setpage_depth(p)=max_depth; + setpage_list(p)=null; + setpage_streams(p)=null; +} +@ + +The default values are replaced by parameters given to the {\tt\BS setpage} +primitive (see section~\secref{pageext}) and by the current values of certain +\TeX\ registers when finishing the page template. +page template itself, + +@<Hi\TeX\ routines@>= +void hfinish_page_group(void) +{ uint8_t k; + pointer p,q,r; + end_graf(); + p=hget_current_page(); + if (p!=null) + { delete_glue_ref(setpage_topskip(p)); + setpage_topskip(p)=top_skip;add_glue_ref(top_skip); + setpage_depth(p)=max_depth; + flush_node_list(setpage_list(p)); + setpage_list(p)=link(head); + } + unsave(); + pop_nest(); +} +@ +@<Hi\TeX\ auxiliar routines@>= + +static pointer hget_current_page(void) +{ pointer p=link(setpage_head); + if (p==null) + print_err("end of output group without setpage node"); + return p; +} + +static pointer hget_current_stream(void) +{ pointer p,s; + p=hget_current_page(); + if (p==null) return null; + s=setpage_streams(p); + if (s==null) + print_err("end of setstream group without setstream node"); + return s; +} +@ + + + +\section{\HINT\ Output} + +\subsection{Initialization} +\noindent + +@<Hi\TeX\ routines@>= +static void hout_init(void) +{ + new_directory(dir_entries); + new_output_buffers(); + max_section_no=2; + hdef_init(); + hput_content_start(); + @<insert an initial language node@>@; +} + +extern int option_global; +void hint_open(void) +{ if (job_name==0) open_log_file(); + pack_job_name(".hnt"); + while (!(hout=open_out((char *)name_of_file+1,"wb"))) + prompt_file_name("file name for output",".hnt"); + hlog=stderr; + option_global=true; + hout_init(); +} +@ + +\subsection{Termination} + +@<Hi\TeX\ routines@>= +#define HITEX_VERSION "1.1" +static void hput_definitions(); +static void hout_terminate(void) +{ hput_content_end(); + hput_definitions(); + hput_directory(); + hput_hint("created by HiTeX Version " HITEX_VERSION); +} + +void hint_close(void) +{ hout_terminate(); + if (hout!=NULL) + fclose(hout); + hout=NULL; +} +@ + + +\subsection{\HINT\ Directory} +There is not much to do here: some code to find a new or existing directory entry, +a variable to hold the number of directory entries allocated, +a function to allocate a new file section, and an auxiliar function to +convert \TeX's file names to ordinary \CEE/ strings. + +@<Find an existing directory entry@>= +for (i=3; i<= max_section_no;i++) + if (dir[i].file_name!=NULL && strcmp(dir[i].file_name,file_name)==0) + return i; +@ + +@<Allocate a new directory entry@>= + i = max_section_no; + i++; + if (i>0xFFFF) QUIT("Too many file sections"); + if (i>=dir_entries) + RESIZE(dir,dir_entries,entry_t); + max_section_no=i; + if (max_section_no>0xFFFF) QUIT("Too many sections"); + dir[i].section_no=i; +@ + +@<Hi\TeX\ macros@>= +#define @[RESIZE(P,S,T)@] \ +{ int _n = (S)*1.4142136 +0.5; \ + if (_n<32) _n=32; \ + { REALLOCATE(P,_n,T); \ + memset((P)+(S),0,(_n-(S))*sizeof(T)); \ + (S)=_n; \ + } \ +} +@ + +@<Hi\TeX\ variables@>= +static int dir_entries=4; +@ + +@<Hi\TeX\ auxiliar routines@>= +static uint16_t hnew_file_section(char *file_name) +{ uint16_t i; + @<Find an existing directory entry@>@; + @<Allocate a new directory entry@>@; + dir[i].file_name=strdup(file_name); + return i; +} +@ + +The following function uses \TeX's function |pack_file_name| +to create a new filename from a name |n|, a direcory or ``area'' |a|, +and an extension |e|. \TeX\ will truncate the new filename +to |file_name_size| characters without warning. The new function +will take a |name_length| equal to | file_name_size| as an +indication that truncation has taken place and terminates the +program. The return value converts a \Pascal\ array, starting with index 1, +into a \CEE/ array starting with index 0. + +@<Hi\TeX\ auxiliar routines@>= +static char *hfile_name(str_number n, char *a, char *e) +{ pack_file_name(n,a,e); + if (name_length>=file_name_size) + QUIT("File name too long %d >= %d",name_length,file_name_size); + return (char *)name_of_file+1; +} + +@ + +\section{\HINT\ Definitions}\label{definitions} +Definitions are used for two reasons: they provide default values for the parameters +that drive \TeX's algorithms running in the \HINT\ viewer, and they provide a compact notation +for \HINT\ content nodes. + +To find the optimal coding for a \HINT\ file, a global knowledge of the \HINT\ file is necessary. +This would require a two pass process: +in the first pass Hi\TeX\ could gather statistics on the use of parameter values and content +nodes as a basis for making definitions and in the second pass it could encode the content using +these definitions. I consider it, however, more reasonable to write such a two pass optimizer +as a separate program which can be used on any \HINT\ file. +Hence Hi\TeX\ uses a much simpler one pass approach: +\itemize + +\item Hi\TeX\ generates definitions for \TeX-parameters using the + values they have when the first non discardable item appears in + |build_page|. This is usually the case after initial style files have + been processed and we can expect that they set useful default values. + +The procedure that generates these definitions is called |hfix_defaults|: + +@<Hi\TeX\ auxiliar routines@>= + +void hfix_defaults(void) +{ @+int i; + DBG(DBGDEF,"Freezing HINT file defaults\n"); + @<Compute the page size@>@; + @<Fix definitions for integer parameters@>@; + @<Fix definitions for dimension parameters@>@; + @<Fix definitions for glue parameters@>@; + @<Fix definitions of page templates@>@; +} + +@ + +\item Hi\TeX\ generates definitions to be used in content nodes on the fly: +Whenever a routine outputs an item for which a definition might be available, +it calls a {\it hget\_\dots\_no} function. This function returns, if possible, +the reference number of a suitable definition. +If no definition is available, the function will try to allocate a new one, +only if all reference numbers from 0 to |0xFF| are already in use, a $-1$ is +returned to indicate failure. + +There are two possible problems with this approach: We might miss a +very common item because it occurs for the first time late in the +input when all reference numbers are already in use. For example an +extensive index might repeat a certain pattern for each entry. And second, we +might make a definition for an item that occurs only once. Taken +together the definition plus the reference to it requires more space +than the same item without a definition. + +We can hope that the first effect does not occur too often, especially if the +\TeX\ file is short, and we know that the second effect is limited by the +total number of definitions we can make plus four byte of overhead per instance. +\enditemize + +Here we initialize the necessary data structures for definitions. +@<Hi\TeX\ auxiliar routines@>= +static void hdef_init(void) +{@+ int i; + @<Switch |hsize| and |vsize| to extended dimensions@>@; + @<Initialize definitions for extended dimensions@>@; + @<Initialize definitions for baseline skips@>@; + @<Initialize definitions for fonts@>@; + @<Initialize definitions for labels@>@; +#if 0 + overfull_rule=0; /* no overfull rules please */ +#endif +} +@ + +After all definitions are ready, we write them using the function +|hput_definitions|. When we output the definitions, +we have to make sure to define references before we use them. +This is achived by using a specific ordering of the +definitions in the function |hput_definitions| and by preventing +the allocation of new definitions as soon as the output of the definition +section has started. The latter has the aditional benefit that the +maximum values do no longer change. + +@<Hi\TeX\ routines@>= +static void hput_definitions() +/* write the definitions into the definitions buffer */ +{ int i; + uint32_t d, m, s; + hput_definitions_start(); + hput_max_definitions(); + @<Output language definitions@>@; + @<Output font definitions@>@; + @<Output integer definitions@>@; + @<Output dimension definitions@>@; + @<Output extended dimension definitions@>@; + @<Output glue definitions@>@; + @<Output baseline skip definitions@>@; + @<Output parameter list definitions@>@; + @<Output discretionary break definitions@>@; + @<Output page template definitions@>@; + hput_definitions_end(); + hput_range_defs(); /* expects the definitions section to be ended */ + hput_label_defs(); +} +@ + + +In the following, we present for each node type the code to generate +the definitions, using a common schema: We define a data structure +called {\it\dots\_defined}, to hold the definitions; we define, if +applicable, the \TeX-parameters; we add an {\it hget\_\dots\_no} +function to allocate new definitions; and we finish with the code to +output the collected definitions. + +Lets start with the most simple case: integers. + +\subsection{Integers} +\subsubsection{Data} +The data structure to hold the integer definitions is a simple array with |0x100| entries. +A more complex data structure, for example a hash table, could speed up searching for +existing definitions but lets keep things simple for now. + +@<Hi\TeX\ variables@>= +static int32_t int_defined[0x100]={0}; +@ +\subsubsection{Mapping} +Before we can generate definitions for \TeX-parameters, we have to map \TeX's +parameter numbers to \HINT\ definition numbers. While it seems more convenient here +to have the reverse mapping, we need the mapping only once to record parameter definitions, +but we will need it repeatedly in the function |hdef_param_node| and the overhead here does +not warant having the mapping in both directions. + +@<Hi\TeX\ variables@>= +static const int hmap_int[] ={@/ +pretolerance_no, /* |pretolerance_code| 0 */ +tolerance_no, /* |tolerance_code| 1 */ +line_penalty_no, /* |line_penalty_code| 2 */ +hyphen_penalty_no, /* |hyphen_penalty_code| 3 */ +ex_hyphen_penalty_no, /* |ex_hyphen_penalty_code| 4 */ +club_penalty_no, /* |club_penalty_code| 5 */ +widow_penalty_no, /* |widow_penalty_code| 6 */ +display_widow_penalty_no, /* |display_widow_penalty_code| 7 */ +broken_penalty_no, /* |broken_penalty_code| 8 */ +-1, /* |bin_op_penalty_code| 9 */ +-1, /* |rel_penalty_code| 10 */ +pre_display_penalty_no, /* |pre_display_penalty_code| 11 */ +post_display_penalty_no, /* |post_display_penalty_code| 12 */ +inter_line_penalty_no, /* |inter_line_penalty_code| 13 */ +double_hyphen_demerits_no, /* |double_hyphen_demerits_code| 14 */ +final_hyphen_demerits_no, /* |final_hyphen_demerits_code| 15 */ +adj_demerits_no, /* |adj_demerits_code| 16 */ +-1, /* |mag_code| 17 */ +-1, /* |delimiter_factor_code| 18 */ +looseness_no, /* |looseness_code| 19 */ +time_no, /* |time_code| 20 */ +day_no, /* |day_code| 21 */ +month_no, /* |month_code| 22 */ +year_no, /* |year_code| 23 */ +-1, /* |show_box_breadth_code| 24 */ +-1, /* |show_box_depth_code| 25 */ +-1, /* |hbadness_code| 26 */ +-1, /* |vbadness_code| 27 */ +-1, /* |pausing_code| 28 */ +-1, /* |tracing_online_code| 29 */ +-1, /* |tracing_macros_code| 30 */ +-1, /* |tracing_stats_code| 31 */ +-1, /* |tracing_paragraphs_code| 32 */ +-1, /* |tracing_pages_code| 33 */ +-1, /* |tracing_output_code| 34 */ +-1, /* |tracing_lost_chars_code| 35 */ +-1, /* |tracing_commands_code| 36 */ +-1, /* |tracing_restores_code| 37 */ +-1, /* |uc_hyph_code| 38 */ +-1, /* |output_penalty_code| 39 */ +-1, /* |max_dead_cycles_code| 40 */ +hang_after_no, /* |hang_after_code| 41*/ +floating_penalty_no /* |floating_penalty_code| 42*/ +}; + + +@ +\subsubsection{Parameters} +Now we can generate the definitions for integer parameters: + +@<Fix definitions for integer parameters@>= + int_defined[zero_int_no]=0; + for (i=pretolerance_code; i<=hang_after_code;i++) + if ( hmap_int[i]>=0) int_defined[hmap_int[i]]=int_par(i); + max_ref[int_kind]=MAX_INT_DEFAULT; +@ + + +\subsubsection{Allocation} +The function |hget_int_no| tries to allocate a predefined integer number; +if not successful, it returns $-1$. + +@<Hi\TeX\ auxiliar routines@>= +static int hget_int_no(int32_t n) +{ int i; + int m =max_ref[int_kind]; + for (i=0; i<=m; i++) + if (n== int_defined[i]) return i; + if (m<0xFF && section_no==2) + { m=++max_ref[int_kind]; int_defined[m]=n; return m; } + else + return -1; +} +@ + +\subsubsection{Output} +Before we give the code to output an integer definition, we declare a macro that +is usefull for all the definitions. |HPUTDEF| takes a function |F| and a reference number |R|. +It is assumed that |F| writes a definition into the output and returns a tag. The macro +will then add the reference number and both tags to the output. +@<Hi\TeX\ macros@>= +#define HPUTDEF(F,R) \ + { uint32_t _p; \ + uint8_t _t; \ + HPUTNODE; /* allocate */ \ + _p=hpos-hstart; \ + HPUT8(0); /* tag */ \ + HPUT8(R); /* reference */ \ + _t=F; \ + hstart[_p]=_t; DBGTAG(_t,hstart+_p); \ + DBGTAG(_t,hpos); HPUT8(_t); \ + } +@ + +Definitions are written to the output only if they differ from Hi\TeX's built in defaults. +@<Output integer definitions@>= + DBG(DBGDEF,"Maximum int reference: %d\n",max_ref[int_kind]); + for (i=max_fixed[int_kind]+1;i<=max_default[int_kind]; i++) + { if (int_defined[i]!=int_defaults[i])@/ + HPUTDEF(hput_int(int_defined[i]),i); + } + for (;i<=max_ref[int_kind]; i++)@/ + HPUTDEF(hput_int(int_defined[i]),i); +@ + + +\subsection{Dimensions} +We proceed as we did for integers, starting with the array that holds the defined dimensions. +\subsubsection{Data} +@<Hi\TeX\ variables@>= +static scaled dimen_defined[0x100]={0}; +@ +\subsubsection{Mapping} +@<Hi\TeX\ variables@>= +static const int hmap_dimen[] ={@/ + -1, /* |par_indent_code| 0 */ + -1, /* |math_surround_code| 1 */ + line_skip_limit_no, /* |line_skip_limit_code| 2 */ + hsize_dimen_no, /* |hsize_code| 3 */ + vsize_dimen_no, /* |vsize_code| 4 */ + max_depth_no, /* |max_depth_code| 5 */ + split_max_depth_no, /* |split_max_depth_code| 6 */ + -1, /* |box_max_depth_code| 7 */ + -1, /* |hfuzz_code| 8 */ + -1, /* |vfuzz_code| 9 */ + -1, /* |delimiter_shortfall_code| 10 */ + -1, /* |null_delimiter_space_code| 11 */ + -1, /* |script_space_code| 12 */ + -1, /* |pre_display_size_code| 13 */ + -1, /* |display_width_code| 14 */ + -1, /* |display_indent_code| 15 */ + -1, /* |overfull_rule_code| 16 */ + hang_indent_no, /* |hang_indent_code| 17 */ + -1, /* |h_offset_code| 18 */ + -1, /* |v_offset_code| 19 */ + emergency_stretch_no /* |emergency_stretch_code| 20 */ +}; +@ + +\subsubsection{Parameters} +@<Fix definitions for dimension parameters@>= + dimen_defined[zero_dimen_no]=0; + for (i=par_indent_code; i<=emergency_stretch_code;i++) + if ( hmap_dimen[i]>=0) dimen_defined[hmap_dimen[i]]=dimen_par(i); + dimen_defined[hsize_dimen_no]=page_h; + dimen_defined[vsize_dimen_no]=page_v; + dimen_defined[quad_no]=quad(cur_font); + dimen_defined[math_quad_no]=math_quad(text_size); + max_ref[dimen_kind]=MAX_DIMEN_DEFAULT; +@ + +\subsubsection{Allocation} +@<Hi\TeX\ auxiliar routines@>= +static int hget_dimen_no(scaled s) +/* tries to allocate a predefined dimension number in the range 0 to 0xFF + if not successful return -1 */ +{ int i; + int m =max_ref[dimen_kind]; + for (i=0; i<=m; i++) + if (s== dimen_defined[i]) return i; + if (m<0xFF && section_no==2) + { m=++max_ref[dimen_kind]; dimen_defined[m]=s; return m; } + else + return -1; +} +@ + +\subsubsection{Output} +@<Output dimension definitions@>= + DBG(DBGDEF,"Maximum dimen reference: %d\n",max_ref[dimen_kind]); + for (i=max_fixed[dimen_kind]+1;i<=max_default[dimen_kind]; i++) + { if (dimen_defined[i]!=dimen_defaults[i]) + HPUTDEF(hput_dimen(dimen_defined[i]),i); + } + for (;i<=max_ref[dimen_kind]; i++) + HPUTDEF(hput_dimen(dimen_defined[i]),i); +@ + + +\subsection{Extended Dimensions} + +\subsubsection{Data} +@<Hi\TeX\ variables@>= +static struct { +scaled w,h,v; } xdimen_defined[0x100]; +@ + +\subsubsection{Initialization} +@<Initialize definitions for extended dimensions@>= + for (i=0; i<=max_fixed[xdimen_kind]; i++) + { xdimen_defined[i].w = xdimen_defaults[i].w; + xdimen_defined[i].h = ONE*xdimen_defaults[i].h; + xdimen_defined[i].v = ONE*xdimen_defaults[i].v; + } +@ + +\subsubsection{Allocation} +To obtain a reference number for an extended dimension, we search the +array and if no match was found, we allocate a new entry, +reallocating the array if needed. +We use the variable |rover| to mark the place where the +last entry was inserted, because +quite often we repeatedly search for the same values. + +@<Hi\TeX\ auxiliar routines@>= +int hget_xdimen_no(pointer p) +{ int i; + for (i=0;i<=max_ref[xdimen_kind];i++) + { if (xdimen_defined[i].w== xdimen_width(p) && + xdimen_defined[i].h== xdimen_hfactor(p) && + xdimen_defined[i].v== xdimen_vfactor(p)) + return i; + } + if (section_no!=2) return -1; + if (i>=0x100) return -1; + max_ref[xdimen_kind]=i; + xdimen_defined[i].w= xdimen_width(p); + xdimen_defined[i].h= xdimen_hfactor(p); + xdimen_defined[i].v= xdimen_vfactor(p); + return i; +} +@ + +@<Hi\TeX\ routines@>= +pointer new_xdimen(scaled w, scaled h, scaled v) +{ pointer p=get_node(xdimen_node_size); + type(p)=whatsit_node;subtype(p)=xdimen_node; + xdimen_width(p)=w; + xdimen_hfactor(p)=h; + xdimen_vfactor(p)=v; + return p; +} +@ + +\subsubsection{Output} +@<Output extended dimension definitions@>= + DBG(DBGDEF,"Maximum xdimen reference: %d\n",max_ref[xdimen_kind]); + for (i=max_fixed[xdimen_kind]+1;i<=max_default[xdimen_kind]; i++) + { xdimen_t x; + x.w=xdimen_defined[i].w; + x.h=xdimen_defined[i].h/(double)ONE; + x.v=xdimen_defined[i].v/(double)ONE; + + if (x.w!=xdimen_defaults[i].w || + x.h!=xdimen_defaults[i].h || + x.v!=xdimen_defaults[i].v) + HPUTDEF(hput_xdimen(&x),i); + } + for (;i<=max_ref[xdimen_kind]; i++) + { xdimen_t x; + x.w=xdimen_defined[i].w; + x.h=xdimen_defined[i].h/(double)ONE; + x.v=xdimen_defined[i].v/(double)ONE; + HPUTDEF(hput_xdimen(&x),i); + } +@ + + +@ +\subsection{Glues} +In general there are two choices on how to store a definition: We can use the data structures used by \TeX\ +or we can use the data structures defined by \HINT. If we are lucky, both of them are the same +as we have seen for integers and dimensions. For extended dimensions, we had to use the \HINT\ data type +|xdimen_t| because \TeX\ has no corresponding data type and uses only reference numbers. +In the case of glue, we definitely have a choice. We decide to use \TeX's pointers to glue specifications +in the hope to save some work when comparing glues for equality, because \TeX\ already reuses +glue specifications and often a simple comparison of pointers might suffice. +\subsubsection{Data} +@<Hi\TeX\ variables@>= +static pointer glue_defined[0x100]; +@ +\subsubsection{Mapping} +@<Hi\TeX\ variables@>= +static int hmap_glue[] ={ + +line_skip_no, /* |line_skip_code| 0 */ +baseline_skip_no, /* |baseline_skip_code| 1 */ +-1, /* |par_skip_code| 2 */ +above_display_skip_no, /* |above_display_skip_code| 3 */ +below_display_skip_no, /* |below_display_skip_code| 4 */ +above_display_short_skip_no, /* |above_display_short_skip_code| 5 */ +below_display_short_skip_no, /* |below_display_short_skip_code| 6 */ +left_skip_no, /* |left_skip_code| 7 */ +right_skip_no, /* |right_skip_code| 8 */ +top_skip_no, /* |top_skip_code| 9 */ +split_top_skip_no, /* |split_top_skip_code| 10 */ +tab_skip_no, /* |tab_skip_code| 11 */ +-1, /* |space_skip_code| 12 */ +-1, /* |xspace_skip_code| 13 */ +par_fill_skip_no /* |par_fill_skip_code| 14 */ +}; +@ +\subsubsection{Parameters} +@<Fix definitions for glue parameters@>= + glue_defined[zero_skip_no]=zero_glue; incr(glue_ref_count(zero_glue)); + for (i=line_skip_code; i<=par_fill_skip_code;i++) + if ( hmap_glue[i]>=0) + { glue_defined[hmap_glue[i]]=glue_par(i); incr(glue_ref_count(glue_par(i)));} + max_ref[glue_kind]=MAX_GLUE_DEFAULT; +@ + + +\subsubsection{Allocation} +Next we define some auxiliar routines to compare glues for equality and to convert glues beween the different representations. + +@<Hi\TeX\ auxiliar routines@>= +int glue_spec_equal(pointer p, pointer q) +{ return (width(q)==width(p) && stretch(q)==stretch(p) && shrink(q)==shrink(p) && + (stretch_order(q)==stretch_order(p) || stretch(q)==0) && + (shrink_order(q)==shrink_order(p)|| shrink(q)==0)); +} + +int glue_equal(pointer p, pointer q) +{ return p==q || glue_spec_equal(p,q); +} + +int glue_t_equal(glue_t *p, glue_t *q) +{ return(p->w.w==q->w.w && p->w.h==q->w.h && p->w.v==q->w.v && + p->p.f== q->p.f && p->m.f==q->m.f && + (p->p.o==q->p.o || p->p.f==0.0) && + (p->m.o==q->m.o || q->m.f==0.0)); +} + +@ + +To find a matching glue we make two passes over the defined glues: +on the first pass we just compare pointers and on the second pass +we also compare values. An alternative approach to speed up searching +is used in section~\secref{paramlist} below. + +@<Hi\TeX\ auxiliar routines@>= +static int hget_glue_no(pointer p) +{ static int rover=0; + int i; + if (p==zero_glue) return zero_skip_no; + for(i=0; i<= max_ref[glue_kind] ; i++) + { if (p==glue_defined[rover]) return rover; + else if (rover==0) + rover=max_ref[glue_kind]; + else + rover--; + } + for(i=0; i<= max_ref[glue_kind] ; i++) + { pointer q=glue_defined[rover]; + if (glue_spec_equal(p,q)) + return rover; + else if (rover==0) + rover=max_ref[glue_kind]; + else + rover--; + } + if (max_ref[glue_kind]<0xFF && section_no==2) + { rover=++max_ref[glue_kind]; + glue_defined[rover]=p; + incr(glue_ref_count(p)); + DBG(DBGDEF,"Defining new glue %d\n",rover); + return rover; + } + else + return -1; +} +@ +\subsubsection{Output} +@<Output glue definitions@>= + DBG(DBGDEF,"Maximum glue reference: %d\n",max_ref[glue_kind]); + for (i=max_fixed[glue_kind]+1;i<=max_default[glue_kind]; i++) + { glue_t g; + to_glue_t(glue_defined[i],&g); + if (!glue_t_equal(&g,&glue_defaults[i])) + HPUTDEF(hput_glue(&g),i); + } + for (;i<=max_ref[glue_kind]; i++) + HPUTDEF(hout_glue_spec(glue_defined[i]),i); +@ + +The above code uses the following conversion routine. +While \HINT\ supports glue that depends on {\tt hsize} and {\tt vsize}, +this is currently not supported by Hi\TeX. +Future versions of Hi\TeX\ should extend glue spec nodes (and kern nodes) +by fields for |hfactor| and |vfactor| which are zero by default. +This would leave most parts of \TeX\ unchanged. +As a work-around one can combine a box with an extended dimension with +a regular glue or kern. +% Care should be taken for the statically allocated glue specs +% deallocation of glue specs is relatively simple +% extended glue and kern values can be restricted to non math mode +@<Hi\TeX\ auxiliar routines@>= +void to_glue_t(pointer p, glue_t *g) +{ g->w.w=width(p); + g->w.h=g->w.v=0.0; + g->p.f=stretch(p)/(double)ONE; g->p.o= stretch_order(p); + g->m.f=shrink(p)/(double)ONE; g->m.o= shrink_order(p); +} +@ + +\subsection{Baseline Skips} +TeX's baseline nodes just store a baseline skip reference number. +We have seen this sitation before when dealing with extended dimensions +and the solution here is the same: a dynamicaly allocated array. +\subsubsection{Data} +@<Hi\TeX\ variables@>= +typedef struct { + pointer ls, bs; /* line skip and baselineskip gluespecs */ + scaled lsl; /* lineskip limit */ +} bl_defined_t; + +static bl_defined_t *bl_defined=NULL; +static int bl_used=0,bl_allocated=0; +@ + +\subsubsection{Initialization} +The zero baseline skip is predefined which prevents an ambiguous info value of zero +in a baseline node. + +@<Initialize definitions for baseline skips@>= + bl_allocated=8; + ALLOCATE(bl_defined,bl_allocated,bl_defined_t); + bl_defined[zero_baseline_no].bs=zero_glue; incr(glue_ref_count(zero_glue)); + bl_defined[zero_baseline_no].ls=zero_glue; incr(glue_ref_count(zero_glue)); + bl_defined[zero_baseline_no].lsl=0; + bl_used= MAX_BASELINE_DEFAULT+1; + max_ref[baseline_kind]= MAX_BASELINE_DEFAULT; +@ +\subsubsection{Allocation} +@<Hi\TeX\ auxiliar routines@>= +int hget_baseline_no(pointer bs, pointer ls, scaled lsl) +{ + static int rover=0; + int i; + for(i=0; i< bl_used; i++) /* search for an existing spec */ + { bl_defined_t *q=&(bl_defined[rover]); + if (glue_equal(bs,q->bs) && glue_equal(ls,q->ls) && lsl==q->lsl) + return rover; + else if (rover==0) + rover=bl_used-1; + else + rover--; + } + if (bl_used>=bl_allocated) + RESIZE(bl_defined,bl_allocated, bl_defined_t); + rover=bl_used++; + if (rover<0x100 && section_no==2) max_ref[baseline_kind]=rover; + if (glue_equal(bs,zero_glue)) + { bl_defined[rover].bs=zero_glue; incr(glue_ref_count(zero_glue)); } + else + { bl_defined[rover].bs=bs; incr(glue_ref_count(bs));} + if (glue_equal(ls,zero_glue)) + { bl_defined[rover].ls=zero_glue; incr(glue_ref_count(zero_glue)); } + else + { bl_defined[rover].ls=ls; incr(glue_ref_count(ls));} + bl_defined[rover].lsl=lsl; + return rover; +} + +@ +\subsubsection{Output} + +The following routine does not allocate a new glue definition, because the +baselinedefinitions are output after the glue definitions. This is not perfect. +@<Hi\TeX\ auxiliar routines@>= +static uint8_t hout_glue_spec(pointer p); +uint8_t hout_baselinespec(int n) +{ info_t i=b000; + pointer p; + scaled s; + s=bl_defined[n].lsl; + if (s!=0) {HPUT32(s); i|=b001;} + p=bl_defined[n].bs; + if (p!=zero_glue) +{ uint8_t *pos; + uint8_t tag; + HPUTNODE; /* allocate */ + pos=hpos; + hpos++; /* tag */ + tag=hout_glue_spec(p); + *pos=tag; DBGTAG(tag,pos); + DBGTAG(tag,hpos); HPUT8(tag); + i|=b100; +} + p=bl_defined[n].ls; + if (p!=zero_glue) +{ uint8_t *pos; + uint8_t tag; + HPUTNODE; /* allocate */ + pos=hpos; + hpos++; /* tag */ + tag=hout_glue_spec(p); + *pos=tag; DBGTAG(tag,pos); + DBGTAG(tag,hpos); HPUT8(tag); + i|=b010; +} + return TAG(baseline_kind,i); +} +@ + +@<Output baseline skip definitions@>= + DBG(DBGDEF,"Defining %d baseline skips\n",max_ref[baseline_kind]); + for (i=1;i<=max_ref[baseline_kind]; i++) + { uint32_t pos=hpos-hstart; + uint8_t tag; + hpos++; /* space for the tag */ + HPUT8(i); /* reference */ + tag=hout_baselinespec(i); + hstart[pos]=tag; + HPUT8(tag); + } +@ +\subsubsection{Printing} +The following function is needed in Hi\TeX\ to produce debugging output if needed. +@<Hi\TeX\ routines@>= +void print_baseline_skip(int i) +{ if (0<=i && i < bl_used) + { print_spec(bl_defined[i].bs,0); print_char(','); + print_spec(bl_defined[i].ls,0); print_char(','); + print_scaled(bl_defined[i].lsl); + } + else + print("unknown"); +} +@ + + + +\subsection{Discretionary breaks} +\subsubsection{Data} +For discretionary breaks, we use again the pointer representation. +@<Hi\TeX\ variables@>= +static pointer dc_defined[0x100]; +@ +\subsubsection{Allocation} +There are no predefined discretionary breaks and so we start with +three auxiliar functions and the +function to get a ``disc'' number. + +The first two routines are used to compare discretionary breaks +in order to reuse already defined disc numbers. +The pre and post break lists must consist entirely of character, +kern, box, rule, and ligature nodes. +Unfortunately a box node might contain all kinds of nodes +and its content might be huge and deeply nested. +The following routine will not make a complete comparison but will give +up if the box content is ``too complex''. + +@<Hi\TeX\ auxiliar routines@>= +static bool list_equal(pointer p, pointer q); +static bool node_equal(pointer p, pointer q) +{ if (is_char_node(p) && is_char_node(q) && + font(p)==font(q) && character(p)==character(q)) + return true; + if (!is_char_node(p) && !is_char_node(q)) + { if (type(p)!=type(q)) return false; + if (type(p)==kern_node && + subtype(p)==subtype(q) && width(p)==width(q)) + return true; + if (type(p)==ligature_node && + character(lig_char(p)) == character(lig_char(q)) && + font(lig_char(p)) == font(lig_char(q))) + return true; + if (type(p)==rule_node && + width(p)==width(q) && height(p)==height(q) && depth(p)==depth(q)) + return true; + if ((type(p)==hlist_node || type(p)==vlist_node) && + width(p)==width(q) && height(p)==height(q) && depth(p)==depth(q) && + shift_amount(p)==shift_amount(q) && + glue_sign(p) == glue_sign(q) && + glue_order(p) == glue_order(q) && + glue_set(p) == glue_set(q) && + list_equal(list_ptr(p),list_ptr(q))) + return true; + } + return false; +} + +static bool list_equal(pointer p, pointer q) +{@+while (true) + { if (p==q) return true; + if (p==null || q==null) return false; + if (!node_equal(p,q)) return false; + p=link(p);q=link(q); + } +} + +static pointer copy_disc_node(pointer p) +{ pointer q; + q=get_node(small_node_size); + pre_break(q)=copy_node_list(pre_break(p)); + post_break(q)=copy_node_list(post_break(p)); + type(q)=type(p); + subtype(q)=subtype(p); /* replace count and explicit bit */ + return q; +} +@ + +@<Hi\TeX\ routines@>= +int hget_disc_no(pointer p) +{ + static int rover=0; + int i; + for(i=0; i<= max_ref[disc_kind]; i++) + { pointer q=dc_defined[rover]; + if ( is_auto_disc(p)==is_auto_disc(q) && replace_count(p)==replace_count(q) && + list_equal(pre_break(p),pre_break(q)) && + list_equal(post_break(p),post_break(q))) + return rover; + else if (rover==0) + rover=max_ref[disc_kind]; + else + rover--; + } + if (max_ref[disc_kind]>=0xFF || section_no!=2) return -1; + + rover=++max_ref[disc_kind]; + dc_defined[rover]=copy_disc_node(p); + @<Allocate font numbers for glyphs in the pre- and post-break lists@>@; + return rover; +} +@ + +When we allocate disc numbers we might have fonts inside the pre- +or post-break list, that never show up anywhere else in the content. +These fonts would then be undefined once we start the definition section. +So we have to make sure, all necessary fonts get defined. + +@<Allocate font numbers for glyphs in the pre- and post-break lists@>= +ensure_font_no(pre_break(p)); +ensure_font_no(post_break(p)); +@ + +\subsubsection{Output} +@<Output discretionary break definitions@>= + DBG(DBGDEF,"Maximum disc reference: %d\n",max_ref[disc_kind]); + for (i=0;i<=max_ref[disc_kind]; i++) + HPUTDEF(hout_disc(dc_defined[i]),i); +@ + + + +\subsection{Parameter Lists}\label{paramlist} +\subsubsection{Data} +We store predefined parameter lists in a hash table in order to speed up +finding existing parameter lists. The parameter list itself is stored as +a byte sequence using the short \HINT\ file format. +We link the table entries in order of increasing reference numbers to be able +to output them in a more ``orderly'' fashion. + +@<Hi\TeX\ variables@>= + +#define PLH_SIZE 313 /* a prime number $\approx2^8\times 1.2$. */ + +struct {int l; /* link */ + uint32_t h; /* hash */ + uint32_t n; /* number */ + uint32_t s; /* size */ + uint8_t *p; /* pointer */} pl_defined[PLH_SIZE]={{0}}; +int pl_head=-1, *pl_tail=&pl_head; +@ + +\subsubsection{Allocation} +Next we define three short auxiliar routines and the |hget_param_list_no| function. + +@<Hi\TeX\ routines@>= + +static uint32_t hparam_list_hash(list_t *l) +{ uint32_t h=0; + uint32_t i; + for (i=0;i<l->s;i++) + h=3*h+hstart[l->p+i]; + return i; +} + +static bool pl_equal(list_t *l, uint8_t *p) +{ uint8_t *q=hstart+l->p; + uint32_t i; + for (i=0; i<l->s; i++) + if (q[i]!=p[i]) return false; + return true; +} + +static void pl_copy(list_t *l, uint8_t *p) +{ uint8_t *q=hstart+l->p; + memcpy(p,q,l->s); +} + +int hget_param_list_no(list_t *l) +{ uint32_t h; + int i; + if (l->s<=0) return -1; + h= hparam_list_hash(l); + i = h%PLH_SIZE; + while (pl_defined[i].p!=NULL) + { if (pl_defined[i].h==h && pl_equal(l,pl_defined[i].p)) + return pl_defined[i].n; + i=i+199; /* some other prime */ + if (i>=PLH_SIZE) i=i-PLH_SIZE; + } + if (max_ref[param_kind]>=0xFF || section_no!=2) return -1; + pl_defined[i].n=++max_ref[param_kind]; + *pl_tail=i; pl_tail=&(pl_defined[i].l); + pl_defined[i].l=-1; + pl_defined[i].h=h; + pl_defined[i].s=l->s; + ALLOCATE(pl_defined[i].p,l->s,uint8_t); + pl_copy(l,pl_defined[i].p); + return pl_defined[i].n; +} +@ + +\subsubsection{Output} +To output parameter lists, we need a function to output a parameter node: + +@<Hi\TeX\ routines@>= +void hdef_param_node(int ptype, int pnumber,int pvalue) +{ + if (ptype==int_type) + { if (pvalue==int_defined[hmap_int[pnumber]]) return; + else HPUTDEF(hput_int(pvalue),hmap_int[pnumber]); + } + else if (ptype==dimen_type) + { if (pvalue==dimen_defined[hmap_dimen[pnumber]]) return; + else HPUTDEF(hput_dimen(pvalue),hmap_dimen[pnumber]); + } + else if (ptype==glue_type) + { if (glue_equal(pvalue,glue_defined[hmap_glue[pnumber]])) return; + else HPUTDEF(hout_glue_spec((pointer)pvalue),hmap_glue[pnumber]); + } + else QUIT("Unexpected parameter type %d",ptype); +} +@ + + +Now we use the linked list starting with |pl_head| to output the predefined +parameter lists sorted by their reference number. + + @<Output parameter list definitions@>= + DBG(DBGDEF,"Defining %d parameter lists\n",max_ref[param_kind]+1); + for (i=pl_head;i>=0;i=pl_defined[i].l) + { int j; + DBG(DBGDEF,"Defining parameter list %d, size 0x%x\n",i,pl_defined[i].s); + j=hsize_bytes(pl_defined[i].s); + HPUTX(1+1+j+1+pl_defined[i].s+1+j+1); + HPUTTAG(param_kind,j+1); + HPUT8(pl_defined[i].n); + hput_list_size(pl_defined[i].s,j); + HPUT8(0x100-j); + memcpy(hpos,pl_defined[i].p,pl_defined[i].s); + hpos=hpos+pl_defined[i].s; + HPUT8(0x100-j); + hput_list_size(pl_defined[i].s,j); + HPUTTAG(param_kind,j+1); + } +@ + +\subsection{Fonts} + +It seems I need: (see email by Karl) + + +|kpse_find_file(name,kpse_fontmap_format,false);| +with name "ps2pk.map" or "psfonts.map" or "ttfonts.map" or cmfonts.map +to get from the tfm name the postscript name. +then I get the |psfont_name| ususaly its the same font name +with .pfb appended +so I can skip it +%#ifdef HAVE_KPSE_ENC_FORMATS +% enc_file=kpse_find_file(encoding,kpse_enc_format,false); +%#else +% enc_file=kpse_find_file(encoding,kpse_tex_ps_header_format,false); +%#endif +%reading the encoding is found in dvipng/dvipnd-src/enc.c + + + +\subsubsection{Data} +To store a font definition, we define the data type |font_t| +and an array |hfonts| of pointers indexed by \HINT\ font numbers. +To map \HINT\ font numbers to \TeX\ font numbers, the |font_t| contains +the |i| field; to map \TeX\ font numbers to \HINT\ font numbers, +we use the array |hmap_font|. + +@<Hi\TeX\ variables@>= +#define MAX_FONTS 0x100 + +typedef struct { + uint8_t i; /* the \TeX\ font number */ + pointer g; /* space glue */ + pointer h; /* default hyphen */ + pointer p[MAX_FONT_PARAMS]; /* font parameters */ + uint16_t m; /* section number of font metric file */ + uint16_t y; /* section number of font glyph file */ +} font_t; + +static font_t *hfonts[MAX_FONTS]={NULL}; +static int hmap_font[MAX_FONTS]; +@ + + + +@<Initialize definitions for fonts@>= + for (i=0;i<0x100;i++) hmap_font[i]=-1; + max_ref[font_kind]=-1; +@ + +\subsubsection{Allocation} +Allocation of a |font_t| record takes place when we translate a \TeX\ font +number to a \HINT\ font number using the function |hget_font_no|, and while +doing so discover that the corresponding \HINT\ font number does not yet exist. +Because the |font_t| structure must be initialized after allocating it, +we start with some auxiliar routines for that purpose. + +@<Hi\TeX\ auxiliar routines@>= +static pointer find_space_glue(internal_font_number f) +{@+font_index @!main_k; + pointer main_p=font_glue[f]; +if (main_p==null) + {@+main_p=new_spec(zero_glue);main_k=param_base[f]+space_code; + width(main_p)=font_info[main_k].sc; /*that's |space(f)|*/ + stretch(main_p)=font_info[main_k+1].sc; /*and |space_stretch(f)|*/ + shrink(main_p)=font_info[main_k+2].sc; /*and |space_shrink(f)|*/ + font_glue[f]=main_p; + } + return main_p; +} +static pointer hget_font_space(uint8_t f) +{ pointer p; + if (space_skip==zero_glue) + p = find_space_glue(f); + else + p=glue_par(space_skip_code); + add_glue_ref(p); + return p; +} + + +static pointer hget_font_hyphen(uint8_t f) +{ pointer p; + int c; + p=new_disc(); + c= hyphen_char[f]; + if (c >= 0 && c < 256) pre_break(p)=new_character(f, c); + return p; +} + + +static void hdef_font_params(pointer p[MAX_FONT_PARAMS]) +{ /* used only for texts */ +} +@ +\goodbreak + +In the following code, |f| is a \TeX\ internal font number +and |g| is the corresponding \HINT\ font number. +\TeX's null-font, a kind of undefined font containing no characters +is replaced by \HINT's font number zero. Actually the nullfont should +never appear in the output, but if it does so, either an error message +or a more sensible replacement font might be in order. + +@<Hi\TeX\ auxiliar routines@>= + +static char *hfind_glyphs(char *filename) +{ char *fname=NULL; + kpse_glyph_file_type file_ret; + fname=kpse_find_file(filename,kpse_type1_format,true); + if (fname==NULL) fname=kpse_find_file(filename,kpse_truetype_format,true); + if (fname==NULL) fname=kpse_find_file(filename,kpse_opentype_format,true); + if (fname==NULL) fname = kpse_find_glyph(filename, option_dpi,kpse_pk_format, &file_ret); + if (fname==NULL) + fprintf(stderr,"Unable to find glyph data for font %s\n",filename),exit(1); + return fname; +} + +static uint8_t hget_font_no(uint8_t f) + +{ int g; + char *n,*fn; + int l; + if (f==0) + { DBG(DBGFONT,"TeX nullfont -> 0\n"); + return 0;@+ + } + g=hmap_font[f]; + DBG(DBGFONT,"Mapping TeX font %d->%d\n",f,g); + if (g>=0) return g; + DBG(DBGDEF,"New TeX font %d\n",f); + if (max_ref[font_kind]>=0x100) + QUIT("too many fonts in use"); + g = ++(max_ref[font_kind]); + ALLOCATE(hfonts[g],1,font_t); + hfonts[g]->i=f; + hmap_font[f]=g; + hfonts[g]->g=hget_font_space(f); + hfonts[g]->h=hget_font_hyphen(f); + pack_file_name(font_name[f], "",".tfm"); + n = kpse_find_tfm((char*)name_of_file+1); + if (n==NULL) + QUIT("Unable to find .tfm file for font %s",(char*)name_of_file+1); + hfonts[g]->m= hnew_file_section(n); + free(n); + pack_file_name(font_name[f], "",""); + n= hfind_glyphs((char*)name_of_file+1); + if (n==NULL) + QUIT("Unable to find glyph file for font %s",(char*)name_of_file+1); + hfonts[g]->y= hnew_file_section(n); + free(n); + return g; +} +@ + +Surprisingly, not all characters that occur in a \HINT\ file are inside the +content section; some characters might hide in the definition section +inside the pre- or post-break list of a predefined discretionary break. +To make sure that the fonts necessary for these characters are included +in the final \HINT\ file, we check these lists to make sure all \TeX\ font +numbers have a corresponting \HINT\ font number. + +@<Hi\TeX\ auxiliar routines@>= +static void ensure_font_no(pointer p) +{ while (p!=null) + { if (is_char_node(p)) + hget_font_no(font(p)); + else if (type(p)==hlist_node||type(p)==vlist_node) + ensure_font_no(list_ptr(p)); + p=link(p); + } +} +@ + +\subsubsection{Output} +@<Output font definitions@>= +{ int f; + DBG(DBGDEF,"Defining %d fonts\n",max_ref[font_kind]+1); + for (f=0;f<=max_ref[font_kind];f++) + { font_t *hf=hfonts[f]; + internal_font_number g=hf->i; + uint32_t pos=hpos-hstart; + info_t i= b000; + DBG(DBGDEF,"Defining font %d size 0x%x\n",f,font_size[g]); + hpos++; HPUTNODE; /* space for the tag and the node */ + HPUT8(f); /* reference */ + hout_string(font_id_text(g)); + if(font_size[g]>0) HPUT32(font_size[g]); + else HPUT32(font_dsize[g]); + HPUT16(hf->m);HPUT16(hf->y); + DBG(DBGDEF,"Defining font space\n"); + HPUTCONTENT(hout_glue_spec,hf->g); + DBG(DBGDEF,"Defining font hyphen\n"); + HPUTCONTENT(hout_disc,hf->h); + hdef_font_params(hf->p); + DBG(DBGDEF,"End of font %d\n",f); + hput_tags(pos,TAG(font_kind,i)); + } +} +@ + +We used the following function to write a \TeX\ string to the \HINT\ file: +@<Hi\TeX\ auxiliar routines@>= + +void hout_string(int s) +{ pool_pointer j; + uint8_t c; + j= str_start[s]; + while(j<str_start[s+1]) + { c= so(str_pool[j++]); + if (c=='%' || c < 0x20 ||c >= 0x7F) + { char str[4]; + snprintf(str,4,"%%%02X",c);/* convert to printable ASCII */ + HPUTX(3); + HPUT8(str[0]); HPUT8(str[1]); HPUT8(str[2]); + } + else + { HPUTX(1); + HPUT8(c); + } + } + HPUT8(0); +} +@ + + +We used the following macro to add tags around the font glue and the font hyphen: + + +@<Hi\TeX\ macros@>= + +#define HPUTCONTENT(F,D) \ + { uint8_t *_p; \ + uint8_t _t; \ + HPUTNODE; /* allocate */ \ + _p=hpos++; /* tag */ \ + _t=F(D); \ + *_p=_t; DBGTAG(_t,_p); \ + DBGTAG(_t,hpos); HPUT8(_t); \ + } +@ + +\subsection{Labels} +The only label that must exist always is the zero label used +to mark the ``home'' position of a document. + +\subsubsection{Initialization} +We allocate the zero label with the first call to |next_label| +and initialize is with the value from |label_defaults|. +We then make sure it can be found under the name ``HINT.home''. + +@<Initialize definitions for labels@>= +{ char nom[]="HINT.home"; + unsigned int h=name_hash(nom)%LABEL_HASH; + int i=insert_hash(h,0,nom); + if (i!=zero_label_no) + QUIT("Trying to allocate the zero label, got %d",i); + labels[zero_label_no]=label_defaults[zero_label_no]; + labels[zero_label_no].next=first_label; + first_label=zero_label_no; + DBG(DBGLABEL,"Defining zero label: pos=0x%x\n",labels[zero_label_no].pos); +} +@ + +\subsection{Page Templates} + +Once we start producing content nodes, we update the maximum numbers +of page templates and streams from |max_page| and |max_stream|. +These values might have changed because the templates were stored in a +format file. + +@<Fix definitions of page templates@>= +max_ref[page_kind]=max_page; +max_ref[stream_kind]=max_stream; +@ + + +\subsubsection{Output} + +As part of a page template, we will see stream insertion nodes. +When we encounter an |stream_node| inside a template definition, +we output a stream insertion point. + +@<cases to output whatsit content nodes@>= + case stream_node: + HPUT8(setstream_number(p)); + tag=TAG(stream_kind,b100); + break; +@ + + +@<Output page template definitions@>= + DBG(DBGDEF,"Maximum page template reference: %d\n",max_page); + { pointer t; + for (t=link(setpage_head);t!=null;t=link(t)) + { uint32_t pos=hpos-hstart; + DBG(DBGDEF,"Defining page template %d\n",setpage_number(i));@/ + hpos++; HPUTNODE; /* space for the tag and the node */ + HPUT8(setpage_number(t)); + hout_string(setpage_name(t)); + HPUT8(setpage_priority(t)); + hout_glue_node(setpage_topskip(t)); + hput_dimen(setpage_depth(t)); + hout_xdimen_node(setpage_height(t)); + hout_xdimen_node(setpage_width(t)); + hout_list_node2(setpage_list(t)); + @<output stream definitions@>@; + hput_tags(pos,TAG(page_kind,0)); + } +} +@ +As part of the output of page template definitions, we output +stream definitions: + +@<output stream definitions@>= +{ pointer p,q; + p = setpage_streams(t); + while (p!=null) + { uint8_t n; + n=setstream_number(p); + DBG(DBGDEF,"Defining stream %d at " SIZE_F "\n",n,hpos-hstart); + HPUTTAG(stream_kind,b100); + HPUT8(n); + hout_xdimen_node(setstream_max(p)); /* maximum height */ + HPUT16(setstream_mag(p)); /* factor */ + HPUT8(setstream_prefered(p)); /* prefered */ + HPUT8(setstream_next(p)); /* next */ + HPUT16(setstream_ratio(p)); /* ratio */ + q=setstream_before(p);setstream_before(p)=null; + hout_list_node2(q);flush_node_list(q); + hout_xdimen_node(setstream_width(p)); + q=setstream_topskip(p); + hout_glue_node(q); delete_glue_ref(q); + q=setstream_after(p);setstream_after(p)=null; + hout_list_node2(q);flush_node_list(q); + q=setstream_height(p); + hout_glue_node(q); delete_glue_ref(q); + HPUTTAG(stream_kind,b100); + p=link(p); + } +} +@ + + + +\section{\HINT\ Content}\label{output} +\TeX\ puts content nodes on the contribution list and once in a while calls |build_page| to +move nodes from the contribution list to the current page. Hi\TeX\ has a special version of +|build_page| that will simply remove nodes from the contribution list and passe them +to the function |hout_node|. + +\noindent +@<Hi\TeX\ routines@>= +static void hout_node(pointer p) +{ uint32_t pos=hpos-hstart; + uint8_t tag; + HPUTNODE; + hpos++; + if(is_char_node(p)) + @<output a character node@>@; + else switch(type(p)) @/ + { @<cases to output content nodes@>@t\1@>@; + default: + MESSAGE("\nOutput of node type=%d subtype=%d not implemented\n", type(p),subtype(p)); + display_node(p); + MESSAGE("End of node"); + hpos--; + return;@t\2@>@; + } + hput_tags(pos,tag); +} +@ +@<Hi\TeX\ function declarations@>= +static void hout_node(pointer p); +@ + +To output \HINT\ nodes, we use the functions defined in {\tt hput.c} from the {\tt shrink} program +(see~\cite{MR:format}). + + +Let's start with character nodes. + +\subsection{Characters} +The processing of a character node consist of three steps: checking for definitions, converting the +\TeX\ node pointed to by |p| to a \HINT\ data type, here a |glyph_t|, and using the +corresponding {\tt hput\_\dots} function to output the node and return the |tag|. +In the following, we will see the same approach in many +small variations for all kinds of nodes. + +@<output a character node@>= +{ glyph_t g; + g.f=hget_font_no(font(p)); + g.c = character(p); + tag=hput_glyph(&g); +} +@ + +\subsection{Penalties} +Integer nodes, which as content nodes are used for penalties, come next. +Except for the embedding between |case| and |break|, the +processing of penalty nodes follows the same pattern we have just seen. + @<cases to output content nodes@>= + case penalty_node: + { int n,i; + i = penalty(p); + if (i>10000) i=10000; + else if (i<-10000) i=-10000; + n=hget_int_no(i); + if (n<0) tag=hput_int(i); + else { HPUT8(n); tag=TAG(penalty_kind,0);} + } + break; +@ + +\subsection{Kerns} +The kern nodes of \TeX\ contain a single dimension and a flag to mark ``explicit'' kerns. + @<cases to output content nodes@>= + case kern_node: + { int n; + n=hget_dimen_no(width(p)); + if (n<0) + { kern_t k; + k.x=(subtype(p)==explicit); + k.d.w=width(p); + k.d.h=k.d.v=0.0; + tag=hput_kern(&k); + } + else + { HPUT8(n); + if (subtype(p)==explicit) tag=TAG(kern_kind,b100); else tag=TAG(kern_kind,b000); + } + } + break; +@ + +\subsection{Extended Dimensions} +Extended dimensions do not consitute content on their own, but nodes +containing an extended dimension are part of other nodes. Here we +define an auxiliar function that checks for a predefined extended +dimension and if found outputs the reference number and returns false; +otherwise it outputs the extended dimension and returns true. + + +@<Hi\TeX\ auxiliar routines@>= +void hout_xdimen_node(pointer p) +{ xdimen_t x; + x.w=xdimen_width(p); + x.h=xdimen_hfactor(p)/(double)ONE; + x.v=xdimen_vfactor(p)/(double)ONE; + hput_xdimen_node(&x); +} +bool hout_xdimen(pointer p) +{int n = hget_xdimen_no(p); + if (n>=0) { HPUT8(n); return false; @+} + else + { hout_xdimen_node(p); return true;@+} +} + +@ + +\subsection{Languages} +We map the language numbers of \TeX\ to \HINT\ language numbers +using the |hlanguage| array. +@<Hi\TeX\ variables@>= +static struct { + uint8_t n; + str_number s; +} hlanguage[0x100]; +@ + +For any language number of \TeX, the following function returns +the corresponding \HINT\ language number. +Since \TeX\ knowns about a maximum of 255 languages, there is +no need for overflow checking. The next function writes a language +node to the output stream. + +@<Hi\TeX\ auxiliar routines@>= +uint8_t hget_language_no(uint8_t n) +{ int i; + for (i=0;i<=max_ref[language_kind]; i++) + if (hlanguage[i].n==n) return i; + i=++max_ref[language_kind]; + hlanguage[i].n=n; + hlanguage[i].s=0; /* language unknown*/ + return i; +} + +uint8_t hout_language(uint8_t n) +{ n=hget_language_no(n); + if (n<7) return TAG(language_kind,n+1); + else + { HPUT8(n); return TAG(language_kind,0); } +} +@ + +After these preparations, the output of a language node is +simple: + +@<cases to output whatsit content nodes@>= +case language_node: + tag=hout_language(what_lang(p)); + break; +@ + +Normaly \TeX\ does not produce an initial language node and +then the language in the \HINT\ file would not be known until +it changes for the first time. + +@<insert an initial language node@>= +{ uint32_t pos = hpos-hstart; + hpos++; + hput_tags(pos,hout_language(language)); +} +@ + +\TeX\ offers currently no simple way to obtain a standardized +language identifier for the current language. So if the +string number of the language is zero, we output the string |"unknown"|; +if somehow the language is known, we output the corresponding string +from \TeX's string pool. + +@<Output language definitions@>= + DBG(DBGDEF,"Maximum language reference: %d\n",max_ref[language_kind]); + for (i=max_fixed[language_kind]+1;i<=max_ref[language_kind]; i++) + { HPUTNODE; + HPUT8(TAG(language_kind,0)); + HPUT8(i); + if (hlanguage[i].s==0) + hput_string("unknown"); + else + hout_string(hlanguage[i].s); + HPUT8(TAG(language_kind,0)); + } +@ + + + +\subsection{Mathematics} +\TeX's math nodes have an optional width---a copy of the mathsurround parameter---while +\HINT\ math nodes do not. Therefore we have to add an explicit kern node if +the width is nonzero. We add it before a ``math on'' node or after a ``math off'' +to get the same behavior in respect to line breaking. + +@<cases to output content nodes@>= + case math_node: + { kern_t k; + k.x=true; + k.d.w=width(p); + k.d.h=k.d.v=0.0; + if (subtype(p)==before) + { tag=TAG(math_kind,b111); + if (width(p)!=0) + { hput_tags(pos,hput_kern(&k)); + pos=hpos-hstart; + HPUTNODE; + hpos++; + } + } + else + { tag=TAG(math_kind,b011); + if (width(p)!=0) + { hput_tags(pos,tag); + pos=hpos-hstart; + HPUTNODE; + hpos++; + tag=hput_kern(&k); + } + } + } + break; +@ + +\subsection{Glue and Leaders} +Because glue specifications and glue nodes are sometimes part of other +nodes, we start with three auxiliar functions: The first simply +converts a Hi\TeX\ glue node into a \HINT\ |glue_t|, outputs it and +returns the tag; the second checks for predefined glues, and the third +outputs a complete glue node including tags. +@<Hi\TeX\ auxiliar routines@>= + +static uint8_t hout_glue_spec(pointer p) +{ @+glue_t g; + to_glue_t(p,&g); + return hput_glue(&g);@+ +} + +static uint8_t hout_glue(pointer p) +{ int n; + n = hget_glue_no(p); + if (n<0) + return hout_glue_spec(p); + else + {@+ HPUT8(n); return TAG(glue_kind,0);@+} +} + +static void hout_glue_node(pointer p) +{ uint8_t *pos; + uint8_t tag; + HPUTNODE; /* allocate */ + pos=hpos; + hpos++; /* tag */ + tag=hout_glue(p); + *pos=tag; DBGTAG(tag,pos); + DBGTAG(tag,hpos); HPUT8(tag); +} +@ + +Since \TeX\ implements leaders as a kind of glue, we have one case statement covering glue and leaders. + +@<cases to output content nodes@>= + case glue_node: + if (subtype(p)< cond_math_glue) /* normal glue */ + tag= hout_glue(glue_ptr(p)); + else if (a_leaders<=subtype(p) && subtype(p)<=x_leaders) /*leaders */ + { hout_glue_node(glue_ptr(p)); + { bool outer_doing_leaders=doing_leaders; + doing_leaders=true; + hout_node(leader_ptr(p)); + doing_leaders=outer_doing_leaders; + } + tag=TAG(leaders_kind,b100|(subtype(p)-a_leaders+1)); + } + else + QUIT("glue subtype %d not implemented\n", subtype(p)); + break; +@ + +\subsection{Discretionary breaks} +Discretionary breaks are needed in font descriptions (see section~\secref{fontdef}). +Therefore we define a function that converts \TeX's |disc_node| pointers +to \HINT's |disc_t|, outputs the discretionary break, and returns the tag. + +@<Hi\TeX\ auxiliar routines@>= + +uint8_t hout_disc(pointer p) +{ disc_t h; + h.x=!is_auto_disc(p); + h.r=replace_count(p); + if (h.x) h.r|=0x80; + if (h.r!=0) HPUT8(h.r); + if (pre_break(p)==null && post_break(p)==null) + h.p.s=h.q.s=0; + else + { uint32_t lpos; + lpos=hpos-hstart; + h.p.k=list_kind; + hout_list_node(pre_break(p),lpos,&(h.p)); + if (post_break(p)==null) + h.q.s=0; + else + { uint32_t lpos; + lpos=hpos-hstart; + h.q.k=list_kind; + hout_list_node(post_break(p),lpos,&(h.q)); + } + } + return hput_disc(&h); +} + +@ + + +@<cases to output content nodes@>= + case disc_node: + { int n; + n=hget_disc_no(p); + if (n<0) + tag=hout_disc(p); + else { HPUT8(n); tag=TAG(disc_kind,0);} + } + break; +@ + +\subsection{Ligatures} +The subtype giving information on left and right boundary characters +is ignored since the \HINT\ viewer will not do ligature or kerning +programms and neither attempt hyphenation. + +@<cases to output content nodes@>= + case ligature_node: + { lig_t l; + pointer q; + l.f=hget_font_no(font(lig_char(p))); + HPUT8(l.f); + l.l.p=hpos-hstart; + hput_utf8(qo(character(lig_char(p)))); + q=lig_ptr(p); + while(q> null) + { hput_utf8(qo(character(q))); + q=link(q); + } + l.l.s=(hpos-hstart)-l.l.p; + tag=hput_ligature(&l); + } + break; +@ +\subsection{Rules} +@<cases to output content nodes@>= + case rule_node: + { rule_t r; + if (is_running(height(p))) r.h=RUNNING_DIMEN; else r.h=height(p); + if (is_running(depth(p))) r.d=RUNNING_DIMEN; else r.d=depth(p); + if (is_running(width(p))) r.w=RUNNING_DIMEN; else r.w=width(p); + tag=hput_rule(&r); + } + break; +@ + +\subsection{Boxes} +@<cases to output content nodes@>= + case hlist_node: + case vlist_node: + if (type(p)==hlist_node) tag=TAG(hbox_kind,0); + else tag=TAG(vbox_kind,0); + tag |= hput_box_dimen(height(p),depth(p),width(p)); + tag |= hput_box_shift(shift_amount(p)); + tag |= hput_box_glue_set((glue_sign(p)==stretching)?+1:-1,glue_set(p),glue_order(p)); + hout_list_node2(list_ptr(p)); + break; + @ + +\subsection{Adjustments} +@<cases to output content nodes@>= + case adjust_node: + hout_list_node2(adjust_ptr(p)); + tag=TAG(adjust_kind,1); + break; +@ + + +\subsection{Insertions} +\TeX's insertions are mapped to \HINT\ streams. + +@<cases to output content nodes@>= +case ins_node: +@<output stream content@>@; +break; +@ + +Here we consider stream content and come back to stream +definitions in section~\secref{streamdef}. +In a \HINT\ stream content node the stream +parameters |floating_penalty|, |split_max_depth|, and +|split_top_skip| are optional. If omitted, the defaults from the stream definition are +used. This is probably also for \TeX\ the most common situation. +It is, however, possible to supply more than one page template with different defaults +and while not very common, \TeX\ might change the parameters at any time. +Because we dont know which is the current page template, +it is not posible to compare the current parameter values against the defaults, +and we have to supply all the parameters always. +In a future version, we might have a \TeX\ primitive that allows us to +signal ``use the defaults''. + +@<output stream content@>= +{ int k,n; + uint32_t pos; + list_t l; + info_t i=b000; + k=subtype(p); + n=hget_stream_no(k); + HPUT8(n); + link(temp_head)=null; + add_par_node(int_type,floating_penalty_code,float_cost(p)); + add_par_node(dimen_type,split_max_depth_code,depth(p)); + add_par_node(glue_type,split_top_skip_code,split_top_ptr(p)); + pos=hpos-hstart; + l.k=param_kind; + n=hout_param_list(link(temp_head),pos,&l); + flush_node_list(link(temp_head));@+ link(temp_head)=null; + if (n>=0) HPUT8(n); else i=b010; + hout_list_node2(ins_ptr(p)); + tag=TAG(stream_kind,i); +} +@ + + +\subsection{Marks} +We currently ignore Marks. + +@<cases to output content nodes@>= + case mark_node: hpos--; return; +@ + +\subsection{Whatsit Nodes}\label{whatsit} +We have added custom whatsit nodes and now we switch based on the subtype. + +@<cases to output content nodes@>= + case whatsit_node: + switch(subtype(p)) + { @<cases to output whatsit content nodes@>@; + default: + MESSAGE("\nOutput of whatsit nodes subtype=%d not implemented\n", subtype(p)); + display_node(p); + MESSAGE("End of node"); + hpos--; + return; + } + break; +@ + +For \TeX's whatsit nodes that handle output files, no code is generated; +hence, we call |out_what| and simply remove the tag byte that is already +in the output. +When the \.{\\write} node arrives here, it is normaly handled +in |hlist_out| or |vlist_out| in an environment determined by +the output routine. For example \LaTeX\ redefines \.{\\protect} +as \.{\\noexpand} and these redefinitions need to be made +before calling |out_what| which expands the token list. +We should therefore add the definitions contained in the output routine +to mimic expanding inside an output routine. + + +@<cases to output whatsit content nodes@>= + case open_node: + case write_node: + case close_node: out_what(p); + case special_node: hpos--; return; +@ + +\subsection{Paragraphs} +When we output a paragraph node, we have to consider a special case: +The parameter list is given by a reference number but the extended dimension +needs an |xdimen| node. In this case the reference number for the parameter +list comes first, while otherwise the extended dimension would come first. +To determine whether ther is a reference number for the parameter list, +the function |hout_param_list| is writing the parameter list to the output. +\noindent +@<cases to output whatsit content nodes@>= +case graf_node: + { uint32_t pos, xpos, xsize; + list_t l; + pointer q; + int n,m; + info_t i=b000; + q=graf_extent(p); + n=hget_xdimen_no(q); + if (n>=0) HPUT8(n); + else + { xpos=hpos-hstart; hout_xdimen_node(p); xsize=(hpos-hstart)-xpos; i|=b100; } + pos=hpos-hstart; + l.k=param_kind; + m=hout_param_list(graf_params(p),pos,&l); + if (m>=0) + { if (i&b100) + { HPUTX(1); + memmove(hstart+xpos+1,hstart+xpos,xsize); + hpos++; + hstart[xpos]=m; + } + else + HPUT8(m); + } + else i|=b010; + pos=hpos-hstart; + l.k=list_kind; + hout_list_node(graf_list(p),pos,&l); + tag=TAG(par_kind,i); + } + break; +@ + +\subsection{Baseline Skips} +@<cases to output whatsit content nodes@>= + case baseline_node: + { int n; + n= baseline_node_no(p); + if (n>0xFF) tag=hout_baselinespec(n); + else + { HPUT8(n); + tag=TAG(baseline_kind,b000); + } + } + break; + @ + +\subsection{Displayed Equations} +@<cases to output whatsit content nodes@>= + case disp_node: + { uint32_t pos; + list_t l; + int n; + info_t i=b000; + pos=hpos-hstart; + l.k=param_kind; + n=hout_param_list(display_params(p),pos,&l); + if (n>=0) HPUT8(n); else i|=b100; + if (display_eqno(p)!=null && display_left(p)) + { hout_node(display_eqno(p)); i|=b010; } + pos=hpos-hstart; + l.k=list_kind; + hout_list_node(display_formula(p),pos,&l); + if (display_eqno(p)!=null && !display_left(p)) + { hout_node(display_eqno(p)); i|=b001; } + tag=TAG(math_kind,i); + /* the |display_no_bs(p)| tells whether the baseline skip is ignored */ + } + break; +@ +\subsection{Extended Boxes} +When we output an extended box, we have to consider a special case: the page templates. +Page templates are boxes that contain insertion points. These insertion points look +like regular insertions but with an empty content list. As a result the |hpack| and +|vpackage| routines might belive that they can compute the dimensions of the box +conntent when in fact they can not. + + +@<cases to output whatsit content nodes@>= + case hset_node: + case vset_node: + { kind_t k= subtype(p)==hset_node?hset_kind:vset_kind; + info_t i=b000; + stretch_t s; + int n=set_extent(p); + i|=hput_box_dimen(height(p),depth(p),width(p)); + i|=hput_box_shift(shift_amount(p)); + s.f=set_stretch(p)/(double)ONE; s.o=set_stretch_order(p); + hput_stretch(&s); + s.f=set_shrink(p)/(double)ONE; s.o=set_shrink_order(p); + hput_stretch(&s); + if (hout_xdimen(n)) i|=b001; + hout_list_node2(list_ptr(p)); + tag=TAG(k,i); + } + break; +@ + +@<cases to output whatsit content nodes@>= + case hpack_node: + case vpack_node: + { kind_t k= (subtype(p)==hpack_node?hpack_kind:vpack_kind); + info_t i=b000; + int n=pack_extent(p); + if (pack_m(p)==additional) i|=b001; + if (shift_amount(p)!=0) { HPUT32(shift_amount(p)); i|=b010; } + if (k==vpack_kind) HPUT32(pack_limit(p)); + if (hout_xdimen(n)) i|=b100; + hout_list_node2(list_ptr(p)); + tag=TAG(k,i); + } + break; +@ + +\subsection{Extended Alignments} +@<cases to output whatsit content nodes@>= +case align_node: + { info_t i=b000; + if (align_m(p)==additional) i|=b001; + if (align_v(p)) i|=b010; + if (hout_xdimen(align_extent(p))) i|=b100; + hout_preamble(align_preamble(p)); + hout_align_list(align_list(p),align_v(p)); + tag=TAG(table_kind,i); + } +break; +@ + +In the preamble, we remove the unset nodes and retain only the list of tabskip glues. +@<Hi\TeX\ auxiliar routines@>= +void hout_preamble(pointer p) +{ pointer q,r; + DBG(DBGBASIC,"Writing Preamble\n"); + q=p; + if (q!=null) r=link(q); else r=null; + while (r!=null) + { if (type(r)==unset_node) + { link(q)=link(r); + link(r)=null; flush_node_list(r); + } + else + q=r; + r=link(q); + } + hout_list_node2(p); + DBG(DBGBASIC,"End Preamble\n"); +} +@ + +In the |align_list| we have to convert the unset nodes back to box nodes or extended box nodes +packaged inside an item node. +When the viewer reads an item node, it will package the extended boxes to their natural size. +This is the size that is needed to compute the maximum width of a column. + +@<Hi\TeX\ auxiliar routines@>= + +static void hout_item(pointer p, uint8_t t, uint8_t s) +{ info_t i=b000; + uint8_t n; + n=span_count(p)+1; + DBG(DBGBASIC,"Writing Item %d/%d->%d/%d\n",type(p),n,t,s); + display_node(p); + if (n==0) QUIT("Span count of item must be positive"); + if (n<7) i=n; else i=7; + HPUTTAG(item_kind,i); + if (i==7) HPUT8(n); + type(p)=t; subtype(p)=s; + hout_node(p); + HPUTTAG(item_kind,i); + DBG(DBGBASIC,"End Item\n"); +} + + +static void hout_item_list(pointer p, bool v) +{ list_t l; + uint32_t pos; + DBG(DBGBASIC,"Writing Item List\n"); + l.k=list_kind; + HPUTTAG(item_kind,b000); + pos=hpos-hstart; + HPUTX(2); + HPUT8(0); /* space for the list tag */ + HPUT8(0); /* space for the list size */ + l.p=hpos-hstart; + while(p> mem_min) + { if (is_char_node(p)) hout_node(p); + else if (type(p)==unset_node) hout_item(p,v?vlist_node:hlist_node,0); + else if (type(p)==unset_set_node) hout_item(p,whatsit_node,v?vset_node:hset_node); + else if (type(p)==unset_pack_node) hout_item(p,whatsit_node,v?vpack_node:hpack_node); + else hout_node(p); + p=link(p); + } + l.s=(hpos-hstart)-l.p; + hput_tags(pos,hput_list(pos+1,&l)); + HPUTTAG(item_kind,b000); + DBG(DBGBASIC,"End Item List\n"); +} + +void hout_align_list(pointer p, bool v) +{ list_t l; + uint32_t pos; + DBG(DBGBASIC,"Writing Align List\n"); + l.k=list_kind; + pos=hpos-hstart; + HPUTX(2); + HPUT8(0); /* space for the tag */ + HPUT8(0); /* space for the list size */ + l.p=pos+2; + while(p> mem_min) + { if (!is_char_node(p) && (type(p)==unset_node||type(p)==unset_set_node||type(p)==unset_pack_node)) + hout_item_list(list_ptr(p),v); + else + hout_node(p); + p=link(p); + } + l.s=(hpos-hstart)-l.p; + hput_tags(pos,hput_list(pos+1,&l)); + DBG(DBGBASIC,"End Align List\n"); +} +@ + +Inside the alignment list we will find various types of unset nodes, we convert them back +to regular nodes and put them inside an item node. + +@<cases to output content nodes@>= +case unset_node: +case unset_set_node: +case unset_pack_node: + + +@ + +\subsection{Lists} +Two functions are provided here: |hout_list| will write a list given by the pointer |p| to the +output at the current position |hpos|. After the list has finished, it will move the list, if necessary, +and add the size information so that the final list will be at position |pos|; +|hout_list_node| uses |hout_list| but adds the tags to form a complete node. + + +@<Hi\TeX\ routines@>= + +static uint8_t hout_list(pointer p, uint32_t pos, list_t *l) +{ l->p=hpos-hstart; + while(p> mem_min) + { hout_node(p); + p=link(p); + } + l->s=(hpos-hstart)-l->p; + return hput_list(pos,l); +} + +static void hout_list_node(pointer p, uint32_t pos, list_t *l) +/* p is a pointer to a node list, + output the node list at position pos (thats where the tag goes) + using l->k as list kind, + and set l->p and l->s. +*/ +{ + hpos=hstart+pos; + HPUTX(3); + HPUT8(0); /* space for the tag */ + HPUT8(0); /* space for the list size */ + HPUT8(0); /* space for the size boundary byte */ + hput_tags(pos,hout_list(p,pos+1,l)); +} + + +static void hout_list_node2(pointer p) +{ list_t l; + uint32_t pos; + pos=hpos-hstart; + l.k=list_kind; + hout_list_node(p,pos,&l); +} +@ + +@<Hi\TeX\ function declarations@>= +static void hout_list_node(pointer p, uint32_t pos, list_t *l); +static void hout_list_node2(pointer p); +static uint8_t hout_list(pointer p, uint32_t pos, list_t *l); +@ + +\subsection{Parameter Lists} + +The next function is like |hout_list_node| but restricted to parameter nodes. + +@<Hi\TeX\ routines@>= + +static int hout_param_list(pointer p, uint32_t pos, list_t *l) +/* p is a pointer to a param node list, + either find a reference number to a predefined parameter list + and return the reference number or + output the node list at position pos (thats where the tag goes) + and set l->k, l->p and l->s, + and return -1; +*/ +{ int n; + hpos=hstart+pos; + if (p==null) + {HPUTX(2); hpos++;hput_tags(pos,TAG(param_kind,1)); l->s=0; return -1;} + HPUTX(3); + HPUT8(0); /* space for the tag */ + HPUT8(0); /* space for the list size */ + HPUT8(0); /* space for the size boundary byte*/ + l->p=hpos-hstart; + while(p> mem_min) + { hdef_param_node(par_type(p),par_number(p),par_value(p).i); + p=link(p); + } + l->s=(hpos-hstart)-l->p; + n=hget_param_list_no(l); + if (n>=0) + hpos=hstart+pos; + else + hput_tags(pos,hput_list(pos+1,l)); + return n; +} +@ + +@<Hi\TeX\ function declarations@>= +static int hout_param_list(pointer p, uint32_t pos, list_t *l); +@ + +\subsection{Labels, Links, and Outlines} +\indent +@<cases to output whatsit content nodes@>= +case label_node: hpos--; new_label(p); return; +case start_link_node: +{ info_t i; + int n=new_start_link(p); + i=b010; + if (n>0xFF) { i|=b001; HPUT16(n);@+} @+else HPUT8(n); + tag= TAG(link_kind,i); +} +break; +case end_link_node: +{ info_t i; + int n=new_end_link(); + i=b000; + if (n>0xFF) { i|=b001; HPUT16(n);@+} @+else HPUT8(n); + tag= TAG(link_kind,i); +} +break; +case outline_node: hpos--; new_outline(p); return; +@ + +The routines to put labels and outlines into the definition section +are defined in {\tt hput.c}. + +\subsection{Images} +\indent +@<cases to output whatsit content nodes@>= + case image_node: + { image_t i; + i.n=image_no(p); + i.w=image_width(p); + i.h=image_height(p); + i.p.f=image_stretch(p)/(double)ONE; + i.p.o=image_stretch_order(p); + i.m.f=image_shrink(p)/(double)ONE; + i.m.o=image_shrink_order(p); + tag=hput_image(&i); + } + break; +@ + + + +\subsection{Text} +The routines in this section are not yet ready. + +@<Hi\TeX\ routines@>= + +#if 0 +static void hchange_text_font(internal_font_number f) +{ uint8_t g; + if (f!=hfont) + { g=get_font_no(f); + if (g<8) + hputcc(FONT0_CHAR+g); + else + { hputcc(FONTN_CHAR); + hputcc(g); + } + hfont=f; + } +} + +static void hprint_text_char(pointer p) +{ uint8_t f,c; + f = font(p); + c = character(p); + hchange_text_font(f); + if (c<=SPACE_CHAR) hputcc(ESC_CHAR); + hputcc(c); +} + + +static void hprint_text_node(pointer p) +{ switch(type(p)) + { case hlist_node: + /* this used to be the |par_indent| case */ + goto nodex; + case glue_node: + if (subtype(p)>= cond_math_glue) goto nodex; + else + { pointer q=glue_ptr(p); + int i; + if (glue_equal(f_space_glue[hfont],q)) + { hputc(SPACE_CHAR); return; } + if (glue_equal(f_xspace_glue[hfont],q)) + { hputcc(XSPACE_CHAR); return; } + if (f_1_glue[hfont]==0 && (subtype(p)-1==space_skip_code)) + { pointer r=glue_par(subtype(p)-1); + add_glue_ref(r); + f_1_glue[hfont]=r; + } + if (f_1_glue[hfont]!=0 && glue_equal(f_1_glue[hfont],q)) + { hputcc(GLUE1_CHAR); return; } + if (f_2_glue[hfont]==0 && (subtype(p)-1==space_skip_code || subtype(p)-1==xspace_skip_code)) + { pointer r=glue_par(subtype(p)-1); + add_glue_ref(r); + f_2_glue[hfont]=r; + } + if (f_2_glue[hfont]!=0 && glue_equal(f_2_glue[hfont],q)) + { hputcc(GLUE2_CHAR); return; } + if (f_3_glue[hfont]==0) + { f_3_glue[hfont]=q; + add_glue_ref(q); + } + if (f_3_glue[hfont]!=0 && glue_equal(f_3_glue[hfont],q)) + { hputcc(GLUE3_CHAR); return; } + i = hget_glue_no(q); + if (i>=0) + { hputcc(GLUEN_CHAR); hputcc(i); return; } + } + break; + case ligature_node: + { int n; + pointer q; + for (n=0,q=lig_ptr(p); n<5 && q!=null; n++,q=link(q)) continue; + if (n==2) hputcc(LIG2_CHAR); + else if (n==3) hputcc(LIG3_CHAR); + else if (n==0) hputcc(LIG0_CHAR); + else goto nodex; + hprint_text_char(lig_char(p)); + for (q=lig_ptr(p);q!=null; q=link(q)) hprint_text_char(q); + return; + } + case disc_node: + if (post_break(p)==null && pre_break(p)!=null && replace_count(p)==0) + { pointer q; + q=pre_break(p); + if (is_char_node(q) && link(q)==null && font(q)==hfont && character(q)== hyphen_char[hfont]) + { if (is_auto_disc(p)) hputcc(DISC1_CHAR); + else hputcc(DISC2_CHAR); + return; + } + } + else if (post_break(p)==null && pre_break(p)==null && replace_count(p)==0 && !is_auto_disc(p)) + { hputcc(DISC3_CHAR); return; } + break; + case math_node: + if(width(p)!=0) goto nodex; + if(subtype(p)==before) hputcc(MATHON_CHAR); + else hputcc(MATHOFF_CHAR); + return; + default: + break; + } +nodex: + hout_node(p); +} + +static void hprint_text(pointer p) +{ internal_font_number f=hfont; + nesting++; + hprint_nesting(); + hprintf("<text "); + while(p> mem_min) + { if (is_char_node(p)) + hprint_text_char(p); + else + hprint_text_node(p); + p=link(p); + } + hchange_text_font(f); + hprintf(">\n"); + nesting--; +} +#endif + +@ + + +\section{\HINT\ Limitations} +\itemize +\item Kerns and glues using a width that depends on \.{\\hsize} or + \.{\\vsize} are not yet supported. +\item Tables where the width of a column depends on \.{\\hsize} or + \.{\\vsize} are not tested and probably not yet supported. +\item The encoding of horizontal lists as texts is not yet supported, + but it would make the \HINT\ file shorter and much better to read + when stretched into long \HINT\ format. +\enditemize + + +\appendix + +\section{Source Files} + +\subsection{Basic types} +To define basic types we use the file {\tt bastypes.h} from~\cite{MR:format}. + +\subsection{Hi\TeX\ routines: \tt hitex.c} +\indent +@p +#include <stdio.h> +#include <kpathsea/kpathsea.h> +#include "basetypes.h" +#include "error.h" +#include "hformat.h" +#include "hput.h" +#include "htex.h" +#include "hitex.h" + +/* from ktex.ch */ + +@<Hi\TeX\ macros@>@; +@<Hi\TeX\ variables@>@; +@<Hi\TeX\ function declarations@>@; + +@<Hi\TeX\ auxiliar routines@>@; + +@<Hi\TeX\ routines@>@; + +@ + + +\subsection{Hi\TeX\ prototypes: \tt hitex.h} +@(hitex.h@>= +extern void hint_open(void); +extern void hint_close(void);@# + +extern pointer new_xdimen(scaled w, scaled h, scaled v); +extern void hget_image_information(pointer p); +extern pointer new_baseline_node(pointer bs, pointer ls, scaled lsl); +extern pointer new_set_node(void); +extern void hline_break(int final_widow_penalty); +extern pointer new_disp_node(void); +extern void add_par_node(eight_bits t, eight_bits n, int v); +extern pointer new_image_node(str_number n, char *a, char *e); +extern pointer new_setpage_node(eight_bits k, str_number n); +extern int hget_stream_no(int i); +extern pointer new_setstream_node(eight_bits n); +extern void hfinish_stream_group(void); +extern void hfinish_page_group(void); +extern void hfinish_stream_before_group(void); +extern void hfinish_stream_after_group(void); +extern void hfinish_outline_group(void); +extern void execute_output(pointer p); +extern void hint_debug_help(void); +@ + +\crosssections + +\plainsection{References} + +{\baselineskip=11pt +\def\bfblrm{\small\rm}% +\def\bblem{\small\it}% +\bibliography{../hint} +\bibliographystyle{plain} +} + +\plainsection{Index} +{ +\def\_{{\tt \UL}} % underline in a string +\catcode`\_=\active \let_=\_ % underline is a letter +\input hitex.ind +} + + \write\cont{} % ensure that the contents file isn't empty +% \write\cont{\catcode `\noexpand\@=12\relax} % \makeatother + \closeout\cont% the contents information has been fully gathered diff --git a/Build/source/texk/web2c/hitexdir/htex.w b/Build/source/texk/web2c/hitexdir/htex.w new file mode 100644 index 00000000000..1115344785d --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/htex.w @@ -0,0 +1,29180 @@ +% This file is part of HINT +% Copyright 2017-2021 Martin Ruckert +% +% Permission is hereby granted, free of charge, to any person obtaining a copy +% of this software and associated documentation files (the "Software"), to deal +% in the Software without restriction, including without limitation the rights +% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +% copies of the Software, and to permit persons to whom the Software is +% furnished to do so, subject to the following conditions: +% +% The above copyright notice and this permission notice shall be +% included in all copies or substantial portions of the Software. +% +% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +% COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, +% WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT +% OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +% THE SOFTWARE. +% +% Except as contained in this notice, the name of the copyright holders shall +% not be used in advertising or otherwise to promote the sale, use or other +% dealings in this Software without prior written authorization from the +% copyright holders. + +% The HINT program is derived from Donald E. Knuth's TeX and the +% subsequent e-TeX extension of TeX. + +% e-TeX is copyright (C) 1999-2012 by P. Breitenlohner (1994,98 by the NTS +% team); all rights are reserved. Copying of this file is authorized only if +% (1) you are P. Breitenlohner, or if (2) you make absolutely no changes to +% your copy. (Programs such as TIE allow the application of several change +% files to tex.web; the master files tex.web and etex.ch should stay intact.) + +% See etex_gen.tex for hints on how to install this program. +% And see etripman.tex for details about how to validate it. + +% This program is directly derived from Donald E. Knuth's TeX; +% the change history which follows and the reward offered for finders of +% bugs refer specifically to TeX; they should not be taken as referring +% to e-TeX, although the change history is relevant in that it +% demonstrates the evolutionary path followed. This program is not TeX; +% that name is reserved strictly for the program which is the creation +% and sole responsibility of Professor Knuth. + +% Version 0 was released in September 1982 after it passed a variety of tests. +% Version 1 was released in November 1983 after thorough testing. +% Version 1.1 fixed ``disappearing font identifiers'' et alia (July 1984). +% Version 1.2 allowed `0' in response to an error, et alia (October 1984). +% Version 1.3 made memory allocation more flexible and local (November 1984). +% Version 1.4 fixed accents right after line breaks, et alia (April 1985). +% Version 1.5 fixed \the\toks after other expansion in \edefs (August 1985). +% Version 2.0 (almost identical to 1.5) corresponds to "Volume B" (April 1986). +% Version 2.1 corrected anomalies in discretionary breaks (January 1987). +% Version 2.2 corrected "(Please type...)" with null \endlinechar (April 1987). +% Version 2.3 avoided incomplete page in premature termination (August 1987). +% Version 2.4 fixed \noaligned rules in indented displays (August 1987). +% Version 2.5 saved cur_order when expanding tokens (September 1987). +% Version 2.6 added 10sp slop when shipping leaders (November 1987). +% Version 2.7 improved rounding of negative-width characters (November 1987). +% Version 2.8 fixed weird bug if no \patterns are used (December 1987). +% Version 2.9 made \csname\endcsname's "relax" local (December 1987). +% Version 2.91 fixed \outer\def\a0{}\a\a bug (April 1988). +% Version 2.92 fixed \patterns, also file names with complex macros (May 1988). +% Version 2.93 fixed negative halving in allocator when mem_min<0 (June 1988). +% Version 2.94 kept open_log_file from calling fatal_error (November 1988). +% Version 2.95 solved that problem a better way (December 1988). +% Version 2.96 corrected bug in "Infinite shrinkage" recovery (January 1989). +% Version 2.97 corrected blunder in creating 2.95 (February 1989). +% Version 2.98 omitted save_for_after at outer level (March 1989). +% Version 2.99 caught $$\begingroup\halign..$$ (June 1989). +% Version 2.991 caught .5\ifdim.6... (June 1989). +% Version 2.992 introduced major changes for 8-bit extensions (September 1989). +% Version 2.993 fixed a save_stack synchronization bug et alia (December 1989). +% Version 3.0 fixed unusual displays; was more \output robust (March 1990). +% Version 3.1 fixed nullfont, disabled \write{\the\prevgraf} (September 1990). +% Version 3.14 fixed unprintable font names and corrected typos (March 1991). +% Version 3.141 more of same; reconstituted ligatures better (March 1992). +% Version 3.1415 preserved nonexplicit kerns, tidied up (February 1993). +% Version 3.14159 allowed fontmemsize to change; bulletproofing (March 1995). +% Version 3.141592 fixed \xleaders, glueset, weird alignments (December 2002). +% Version 3.1415926 was a general cleanup with minor fixes (February 2008). +% Version 3.14159265 was similar (January 2014). + +% A reward of $327.68 will be paid to the first finder of any remaining bug. + +% A preliminary version of TeX--XeT was released in April 1992. +% TeX--XeT version 1.0 was released in June 1992, +% version 1.1 prevented arith overflow in glue computation (Oct 1992). +% A preliminary e-TeX version 0.95 was operational in March 1994. +% Version 1.0beta was released in May 1995. +% Version 1.01beta fixed bugs in just_copy and every_eof (December 1995). +% Version 1.02beta allowed 256 mark classes (March 1996). +% Version 1.1 changed \group{type,level} -> \currentgroup{type,level}, +% first public release (October 1996). +% Version 2.0 development was started in March 1997; +% fixed a ligature-\beginR bug in January 1998; +% was released in March 1998. +% Version 2.1 fixed a \marks bug (when min_halfword<>0) (January 1999). +% Version 2.2 development was started in Feb 2003; released in Oct 2004. +% fixed a bug in sparse array handling (0=>null), Jun 2002; +% fixed a bug in \lastnodetype (cur_val=>cur_val_level) +% reported by Hartmut Henkel <hartmut_henkel@@gmx.de>, +% fix by Fabrice Popineau <Fabrice.Popineau@@supelec.fr>, +% Jan 2004; +% another bug in sparse array handling (cur_ptr=>cur_chr) +% reported by Taco Hoekwater <taco@@elvenkind.com>, Jul 2004; +% fixed a sparse array reference count bug (\let,\futurelet), +% fix by Bernd Raichle <berd@@dante.de>, Aug 2004; +% reorganized handling of banner, additional token list and +% integer parameters, and similar in order to reduce the +% interference between eTeX, pdfTeX, and web2c change files. +% adapted to tex.web 3.141592, revised glue rounding for mixed +% direction typesetting; +% fixed a bug in the revised glue rounding code, detected by +% Tigran Aivazian <tigran@@aivazian.fsnet.co.uk>, Oct 2004. +% Version 2.3 development was started in Feb 2008; released in Apr 2011. +% fixed a bug in hyph_code handling (\savinghyphcodes) +% reported by Vladimir Volovich <vvv@@vsu.ru>, Feb 2008. +% fixed the error messages for improper use of \protected, +% reported by Heiko Oberdiek +% <heiko.oberdiek@@googlemail.com>, May 2010. +% some rearrangements to reduce interferences between +% e-TeX and pTeX, in part suggested by Hironori Kitagawa +% <h_kitagawa2001@@yahoo.co.jp>, Mar 2011. +% Version 2.4 fixed an uninitialized line number bug, released in May 2012. +% Version 2.5 development was started in Aug 2012; released in Feb 2013. +% better tracing of font definitions, reported by +% Bruno Le Floch <blflatex@@gmail.com>, Jul 2012. +% Version 2.6 development was started in Mar 2013; released in ??? 201?. +% enable hyphenation of text between \beginL and \endL or +% between \beginR and \endR, problem reported by +% Vafa Khalighi <vafalgk@@gmail.com>, Nov 2013. +% better handling of right-to-left text -- to be done. + +% Although considerable effort has been expended to make the e-TeX program +% correct and reliable, no warranty is implied; the author disclaims any +% obligation or liability for damages, including but not limited to +% special, indirect, or consequential damages arising out of or in +% connection with the use or performance of this software. This work has +% been a ``labor of love'' and the author hopes that users enjoy it. + +% Here is TeX material that gets inserted after \input webmac +\def\hang{\hangindent 3em\noindent\ignorespaces} +\def\hangg#1 {\hang\hbox{#1 }} +\def\textindent#1{\hangindent2.5em\noindent\hbox to2.5em{\hss#1 }\ignorespaces} +\font\ninerm=cmr9 +\let\mc=\ninerm % medium caps for names like SAIL +\def\eTeX{$\varepsilon$-\TeX} +\font\revrm=xbmc10 % for right-to-left text +% to generate xbmc10 (i.e., reflected cmbx10) use a file +% xbmc10.mf containing: +%+++++++++++++++++++++++++++++++++++++++++++++++++ +% if unknown cmbase: input cmbase fi +% extra_endchar := extra_endchar & +% "currentpicture:=currentpicture " & +% "reflectedabout((.5[l,r],0),(.5[l,r],1));"; +% input cmbx10 +%+++++++++++++++++++++++++++++++++++++++++++++++++ +\ifx\beginL\undefined % this is TeX + \def\XeT{X\kern-.125em\lower.5ex\hbox{E}\kern-.1667emT} + \def\TeXeT{\TeX-\hbox{\revrm \XeT}} % for TeX-XeT + \def\TeXXeT{\TeX-\hbox{\revrm -\XeT}} % for TeX--XeT +\else + \ifx\eTeXversion\undefined % this is \TeXeT + \def\TeXeT{\TeX-{\revrm\beginR\TeX\endR}} % for TeX-XeT + \def\TeXXeT{\TeX-{\revrm\beginR\TeX-\endR}} % for TeX--XeT + \else % this is \eTeX + \def\TeXeT{\TeX-{\TeXXeTstate=1\revrm\beginR\TeX\endR}} % for TeX-XeT + \def\TeXXeT{\TeX-{\TeXXeTstate=1\revrm\beginR\TeX-\endR}} % for TeX--XeT + \fi +\fi +\def\PASCAL{Pascal} +\def\ph{\hbox{Pascal-H}} +\def\pct!{{\char`\%}} % percent sign in ordinary text +\def\grp{\.{\char'173...\char'175}} +\font\logo=logo10 % font used for the METAFONT logo +\def\MF{{\logo META}\-{\logo FONT}} +\def\<#1>{$\langle#1\rangle$} +\def\section{\mathhexbox278} + +\def\(#1){} % this is used to make section names sort themselves better +\def\9#1{} % this is used for sort keys in the index via @@:sort key}{entry@@> + +\let\@@=\relax % we want to be able to \write a \? + +\def\title{k\TeX} +% system dependent redefinitions of \title should come later +% and should use: +% \toks0=\expandafter{\title} +% \edef\title{...\the\toks0...} +\let\maybe=\iffalse % print only changed modules +\def\topofcontents{\hsize 5.5in + \vglue 0pt plus 1fil minus 1.5in + \def\@@##1]{\hbox to 1in{\hfil##1.\ }} + } +\def\botofcontents{\vskip 0pt plus 1fil minus 1.5in} +\pageno=3 +\def\glob{13} % this should be the section number of "<Global...>" +\def\gglob{20, 26} % this should be the next two sections of "<Global...>" + +\def\.#1{\leavevmode\hbox{\tentex % typewriter type for strings + \let\\=\BS % backslash in a string + \let\'=\RQ % right quote in a string + \let\`=\LQ % left quote in a string + \let\{=\LB % left brace in a string + \let\}=\RB % right brace in a string + \let\~=\TL % tilde in a string + \let\ =\SP % space in a string + \let\_=\UL % underline in a string + \let\&=\AM % ampersand in a string + #1\kern.05em}} +\def\^{\ifmmode\mathchar"222 \else\char`^ \fi} % pointer or hat +\def\LQ{{\tt\char'22}} % left quote in a string +\def\RQ{{\tt\char'23}} % right quote in a string +\def\dotdot{\mathrel{.\,.}} % double dot, used only in math mode +@s dotdot TeX +@* Introduction. +This is \eTeX, a program derived from and extending the capabilities of +\TeX, a document compiler intended to produce typesetting of high +quality. +The \PASCAL\ program that follows is the definition of \TeX82, a standard +@:PASCAL}{\PASCAL@> +@!@:TeX82}{\TeX82@> +version of \TeX\ that is designed to be highly portable so that identical output +will be obtainable on a great variety of computers. + +The main purpose of the following program is to explain the algorithms of \TeX\ +as clearly as possible. As a result, the program will not necessarily be very +efficient when a particular \PASCAL\ compiler has translated it into a +particular machine language. However, the program has been written so that it +can be tuned to run efficiently in a wide variety of operating environments +by making comparatively few changes. Such flexibility is possible because +the documentation that follows is written in the \.{WEB} language, which is +at a higher level than \PASCAL; the preprocessing step that converts \.{WEB} +to \PASCAL\ is able to introduce most of the necessary refinements. +Semi-automatic translation to other languages is also feasible, because the +program below does not make extensive use of features that are peculiar to +\PASCAL. + +A large piece of software like \TeX\ has inherent complexity that cannot +be reduced below a certain level of difficulty, although each individual +part is fairly simple by itself. The \.{WEB} language is intended to make +the algorithms as readable as possible, by reflecting the way the +individual program pieces fit together and by providing the +cross-references that connect different parts. Detailed comments about +what is going on, and about why things were done in certain ways, have +been liberally sprinkled throughout the program. These comments explain +features of the implementation, but they rarely attempt to explain the +\TeX\ language itself, since the reader is supposed to be familiar with +{\sl The \TeX book}. +@.WEB@> +@:TeXbook}{\sl The \TeX book@> + +@ The present implementation has a long ancestry, beginning in the summer +of~1977, when Michael~F. Plass and Frank~M. Liang designed and coded +a prototype +@^Plass, Michael Frederick@> +@^Liang, Franklin Mark@> +@^Knuth, Donald Ervin@> +based on some specifications that the author had made in May of that year. +This original proto\TeX\ included macro definitions and elementary +manipulations on boxes and glue, but it did not have line-breaking, +page-breaking, mathematical formulas, alignment routines, error recovery, +or the present semantic nest; furthermore, +it used character lists instead of token lists, so that a control sequence +like \.{\\halign} was represented by a list of seven characters. A +complete version of \TeX\ was designed and coded by the author in late +1977 and early 1978; that program, like its prototype, was written in the +{\mc SAIL} language, for which an excellent debugging system was +available. Preliminary plans to convert the {\mc SAIL} code into a form +somewhat like the present ``web'' were developed by Luis Trabb~Pardo and +@^Trabb Pardo, Luis Isidoro@> +the author at the beginning of 1979, and a complete implementation was +created by Ignacio~A. Zabala in 1979 and 1980. The \TeX82 program, which +@^Zabala Salelles, Ignacio Andr\'es@> +was written by the author during the latter part of 1981 and the early +part of 1982, also incorporates ideas from the 1979 implementation of +@^Guibas, Leonidas Ioannis@> +@^Sedgewick, Robert@> +@^Wyatt, Douglas Kirk@> +\TeX\ in {\mc MESA} that was written by Leonidas Guibas, Robert Sedgewick, +and Douglas Wyatt at the Xerox Palo Alto Research Center. Several hundred +refinements were introduced into \TeX82 based on the experiences gained with +the original implementations, so that essentially every part of the system +has been substantially improved. After the appearance of ``Version 0'' in +September 1982, this program benefited greatly from the comments of +many other people, notably David~R. Fuchs and Howard~W. Trickey. +A final revision in September 1989 extended the input character set to +eight-bit codes and introduced the ability to hyphenate words from +different languages, based on some ideas of Michael~J. Ferguson. +@^Fuchs, David Raymond@> +@^Trickey, Howard Wellington@> +@^Ferguson, Michael John@> + +No doubt there still is plenty of room for improvement, but the author +is firmly committed to keeping \TeX82 ``frozen'' from now on; stability +and reliability are to be its main virtues. + +On the other hand, the \.{WEB} description can be extended without changing +the core of \TeX82 itself, and the program has been designed so that such +extensions are not extremely difficult to make. +The |banner| string defined here should be changed whenever \TeX\ +undergoes any modifications, so that it will be clear which version of +\TeX\ might be the guilty party when a problem arises. +@^extensions to \TeX@> +@^system dependencies@> + +This program contains code for various features extending \TeX, +therefore this program is called `\eTeX' and not +`\TeX'; the official name `\TeX' by itself is reserved +for software systems that are fully compatible with each other. +A special test suite called the ``\.{TRIP} test'' is available for +helping to determine whether a particular implementation deserves to be +known as `\TeX' [cf.~Stanford Computer Science report CS1027, +November 1984]. + +A similar test suite called the ``\.{e-TRIP} test'' is available for +helping to determine whether a particular implementation deserves to be +known as `\eTeX'. + +@d eTeX_version 2 /* \.{\\eTeXversion} */ +@d eTeX_revision ".6" /* \.{\\eTeXrevision} */ +@d eTeX_version_string "-2.6" /*current \eTeX\ version*/ +@# +@d eTeX_banner "This is e-TeX, Version 3.14159265" " (HINT) " eTeX_version_string + /*printed when \eTeX\ starts*/ +@# +@d TeX_banner "This is TeX, Version 3.14159265 (HINT)" /*printed when \TeX\ starts*/ +@# +@d banner eTeX_banner +@# +@d TEX ETEX /*change program name into |ETEX|*/ +@# +@d eTeX_states 1 /*number of \eTeX\ state variables in |eqtb|*/ + +@ Different \PASCAL s have slightly different conventions, and the present +@!@:PASCAL H}{\ph@> +program expresses \TeX\ in terms of the \PASCAL\ that was +available to the author in 1982. Constructions that apply to +this particular compiler, which we shall call \ph, should help the +reader see how to make an appropriate interface for other systems +if necessary. (\ph\ is Charles Hedrick's modification of a compiler +@^Hedrick, Charles Locke@> +for the DECsystem-10 that was originally developed at the University of +Hamburg; cf.\ {\sl SOFTWARE---Practice \AM\ Experience \bf6} (1976), +29--42. The \TeX\ program below is intended to be adaptable, without +extensive changes, to most other versions of \PASCAL, so it does not fully +use the admirable features of \ph. Indeed, a conscious effort has been +made here to avoid using several idiosyncratic features of standard +\PASCAL\ itself, so that most of the code can be translated mechanically +into other high-level languages. For example, the `\&{with}' and `\\{new}' +features are not used, nor are pointer types, set types, or enumerated +scalar types; there are no `\&{var}' parameters, except in the case of files +--- \eTeX, however, does use `\&{var}' parameters for the |reverse| function; +there are no tag fields on variant records; there are no assignments +|double=int|; no procedures are declared local to other procedures.) + +The portions of this program that involve system-dependent code, where +changes might be necessary because of differences between \PASCAL\ compilers +and/or differences between +operating systems, can be identified by looking at the sections whose +numbers are listed under `system dependencies' in the index. Furthermore, +the index entries for `dirty \PASCAL' list all places where the restrictions +of \PASCAL\ have not been followed perfectly, for one reason or another. +@!@^system dependencies@> +@!@^dirty \PASCAL@> + +Incidentally, \PASCAL's standard |round| function can be problematical, +because it disagrees with the IEEE floating-point standard. +Many implementors have +therefore chosen to substitute their own home-grown rounding procedure. + +@ The following is an outline of the program, whose +components will be filled in later, using the conventions of \.{WEB}. +@.WEB@> +For example, the portion of the program called `\X\glob:Global +variables\X' below will be replaced by a sequence of variable declarations +that starts in $\section\glob$ of this documentation. In this way, we are able +to define each individual global variable when we are prepared to +understand what it means; we do not have to define all of the globals at +once. Cross references in $\section\glob$, where it says ``See also +sections \gglob, \dots,'' also make it possible to look at the set of +all global variables, if desired. Similar remarks apply to the other +portions of the program. + +@p @<Header files and function declarations@>@; +#include "htex.h" +#include "hitex.h" +@<Global variables@>@; +@# + +static void initialize(void) /*this procedure gets things started properly*/ + {@+@<Local variables for initialization@>@; + @<Initialize whatever \TeX\ might access@>; + } @# +@<Basic printing procedures@>@; +@<Error handling procedures@>@; + +@ The overall \TeX\ program begins with the heading just shown, after which +comes a bunch of procedure declarations and function declarations. +Finally we will get to the main program, which begins with the +comment `|start_here|'. If you want to skip down to the +main program now, you can look up `|start_here|' in the index. +But the author suggests that the best way to understand this program +is to follow pretty much the order of \TeX's components as they appear in the +\.{WEB} description you are now reading, since the present ordering is +intended to combine the advantages of the ``bottom up'' and ``top down'' +approaches to the problem of understanding a somewhat complicated system. + +@ There is no need to declare labels in \CEE/, but occasionally +it is necessary to insert header files and declare functions +very early in the program. For example, the function |s_no| +which uses |make_string| to convert a \CEE/ string into +a string number is used in |initialize| and needs a forward +declaration. + +@<Header files and function declarations@>= +extern int s_no(const char *str); + +@ Some of the code below is intended to be used only when diagnosing the +strange behavior that sometimes occurs when \TeX\ is being installed or +when system wizards are fooling around with \TeX\ without quite knowing +what they are doing. Such code will not normally be compiled; it is +delimited by the codewords `$|debug|\ldots|debug|$', with apologies +to people who wish to preserve the purity of English. + +Similarly, there is some conditional code delimited by +`$|stat|\ldots|tats|$' that is intended for use when statistics are to be +kept about \TeX's memory usage. The |stat| $\ldots$ |tats| code also +implements diagnostic information for \.{\\tracingparagraphs} and +\.{\\tracingpages}. +@^debugging@> + +@ This program has two important variations: (1) There is a long and slow +version called \.{INITEX}, which does the extra calculations needed to +@.INITEX@> +initialize \TeX's internal tables; and (2)~there is a shorter and faster +production version, which cuts the initialization to a bare minimum. +Parts of the program that are needed in (1) but not in (2) are delimited by +|#ifdef| |INIT|\dots\ |#endif|. + +\TeX\ Live has established the common practice +to select the initialization code at runtime +using the |iniversion| variable. + +@<Initialize whatever...@>= +@<Set initial values of key variables@>@/ +#ifdef @!INIT +if (iniversion) {@+@<Initialize table entries (done by \.{INITEX} only)@>@;@+} +#endif + +@ Most of the external declarations needed are included using standard +header files. + +@s uint8_t int +@s int16_t int +@s uint16_t int +@s int32_t int +@s uint32_t int +@s halfword int +@s in TeX +@s line normal +@s to do + +@<Header files and function declarations@>= +#include <stdint.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <math.h> + +@ Further it is necessary to define some build in primitives of +\PASCAL\ that are otherwise not available in \CEE/. +@:PASCAL H}{\ph@> + +@d odd(X) ((X)&1) +@d chr(X) ((unsigned char)(X)) +@d ord(X) ((unsigned int)(X)) +@d abs(X) ((X)>-(X)?(X):-(X)) +@d round(X) ((int)((X)>=0.0?floor((X)+0.5):ceil((X)-0.5))) + +@ The following parameters can be changed at compile time to extend or +reduce \TeX's capacity. They may have different values in \.{INITEX} and +in production versions of \TeX. +@.INITEX@> +@^system dependencies@> + +@<Constants...@>= +@!mem_max=5000000, /*greatest index in \TeX's internal |mem| array; + must be strictly less than |max_halfword|; + must be equal to |mem_top| in \.{INITEX}, otherwise | >= mem_top|*/ +@!mem_min=0, /*smallest index in \TeX's internal |mem| array; + must be |min_halfword| or more; + must be equal to |mem_bot| in \.{INITEX}, otherwise | <= mem_bot|*/ +@!buf_size=2000000, /*maximum number of characters simultaneously present in + current lines of open files and in control sequences between + \.{\\csname} and \.{\\endcsname}; must not exceed |max_halfword|*/ +@!error_line=79, /*width of context lines on terminal error messages*/ +@!half_error_line=50, /*width of first lines of contexts in terminal + error messages; should be between 30 and |error_line-15|*/ +@!max_print_line=79, /*width of longest text lines output; should be at least 60*/ +@!stack_size=5000, /*maximum number of simultaneous input sources*/ +@!max_in_open=15, /*maximum number of input files and error insertions that + can be going on simultaneously*/ +@!font_max=255, /*maximum internal font number; must not exceed |max_quarterword| + and must be at most |font_base+256|*/ +@!font_mem_size=8000000, /*number of words of |font_info| for all fonts*/ +@!param_size=10000, /*maximum number of simultaneous macro parameters*/ +@!nest_size=500, /*maximum number of semantic levels simultaneously active*/ +@!max_strings=500000, /*maximum number of strings; must not exceed |max_halfword|*/ +@!string_vacancies=90000, /*the minimum number of characters that should be + available for the user's control sequences and font names, + after \TeX's own error messages are stored*/ +@!pool_size=6250000, /*maximum number of characters in strings, including all + error messages and help texts, and the names of all fonts and + control sequences; must exceed |string_vacancies| by the total + length of \TeX's own strings, which is currently about 23000*/ +@!save_size=100000, /*space for saving values outside of current group; must be + at most |max_halfword|*/ +@!trie_size=1000000, /*space for hyphenation patterns; should be larger for + \.{INITEX} than it is in production versions of \TeX*/ +@!trie_op_size=35111, /*space for ``opcodes'' in the hyphenation patterns*/ +@!dvi_buf_size=16384, /*size of the output buffer; must be a multiple of 8*/ +@!file_name_size=1024, /*file names shouldn't be longer than this*/ +@!empty_string=256 /*the empty string follows after 256 characters*/ + +@ Like the preceding parameters, the following quantities can be changed +at compile time to extend or reduce \TeX's capacity. But if they are changed, +it is necessary to rerun the initialization program \.{INITEX} +@.INITEX@> +to generate new tables for the production \TeX\ program. +One can't simply make helter-skelter changes to the following constants, +since certain rather complex initialization +numbers are computed from them. They are defined here using +\.{WEB} macros, instead of being put into \PASCAL's |const| list, in order to +emphasize this distinction. + +@d mem_bot 0 /*smallest index in the |mem| array dumped by \.{INITEX}; + must not be less than |mem_min|*/ +@d mem_top 5000000 /*largest index in the |mem| array dumped by \.{INITEX}; + must be substantially larger than |mem_bot| + and not greater than |mem_max|*/ +@d font_base 0 /*smallest internal font number; must not be less + than |min_quarterword|*/ +@d hash_size 15000 /*maximum number of control sequences; it should be at most + about |(mem_max-mem_min)/(double)10|*/ +@d hash_prime 8501 /*a prime number equal to about 85\pct! of |hash_size|*/ +@d hyph_size 8191 /*another prime; the number of \.{\\hyphenation} exceptions*/ +@^system dependencies@> + +@ In case somebody has inadvertently made bad settings of the ``constants,'' +\TeX\ checks them using a global variable called |bad|. + +This is the first of many sections of \TeX\ where global variables are +defined. + +@<Glob...@>= +static int @!bad; /*is some ``constant'' wrong?*/ + +@ Later on we will say `\ignorespaces|if (mem_max >= max_halfword) bad=14|', +or something similar. (We can't do that until |max_halfword| has been defined.) + +@<Check the ``constant'' values for consistency@>= +bad=0; +if ((half_error_line < 30)||(half_error_line > error_line-15)) bad=1; +if (max_print_line < 60) bad=2; +if (dvi_buf_size%8!=0) bad=3; +if (mem_bot+1100 > mem_top) bad=4; +if (hash_prime > hash_size) bad=5; +if (max_in_open >= 128) bad=6; +if (mem_top < 256+11) bad=7; /*we will want |null_list > 255|*/ + +@ Labels are given symbolic names by the following definitions, so that +occasional |goto| statements will be meaningful. We insert the label +`|end|' just before the `\ignorespaces|} |\unskip' of a procedure in +which we have used the `|goto end|' statement defined below; the label +`|restart|' is occasionally used at the very beginning of a procedure; and +the label `|reswitch|' is occasionally used just prior to a |case| +statement in which some cases change the conditions and we wish to branch +to the newly applicable case. Loops that are set up with the |loop| +construction defined below are commonly exited by going to `|done|' or to +`|found|' or to `|not_found|', and they are sometimes repeated by going to +`|resume|'. If two or more parts of a subroutine start differently but +end up the same, the shared code may be gathered together at +`|common_ending|'. + +Incidentally, this program never declares a label that isn't actually used, +because some fussy \PASCAL\ compilers will complain about redundant labels. + +@ Here are some macros for common programming idioms. + +@d incr(A) A=A+1 /*increase a variable by unity*/ +@d decr(A) A=A-1 /*decrease a variable by unity*/ +@d negate(A) A=-A /*change the sign of a variable*/ +@d loop @+while (true) @+ /*repeat over and over until a |goto| happens*/ +@f loop else + /*\.{WEB}'s |else| acts like `\ignorespaces|while true do|\unskip'*/ +@d do_nothing /*empty statement*/ +@d empty 0 /*symbolic name for a null constant*/ + +@* The character set. +In order to make \TeX\ readily portable to a wide variety of +computers, all of its input text is converted to an internal eight-bit +code that includes standard ASCII, the ``American Standard Code for +Information Interchange.'' This conversion is done immediately when each +character is read in. Conversely, characters are converted from ASCII to +the user's external representation just before they are output to a +text file. + +Such an internal code is relevant to users of \TeX\ primarily because it +governs the positions of characters in the fonts. For example, the +character `\.A' has ASCII code $65=0101$, and when \TeX\ typesets +this letter it specifies character number 65 in the current font. +If that font actually has `\.A' in a different position, \TeX\ doesn't +know what the real position is; the program that does the actual printing from +\TeX's device-independent files is responsible for converting from ASCII to +a particular font encoding. +@^ASCII code@> + +\TeX's internal code also defines the value of constants +that begin with a reverse apostrophe; and it provides an index to the +\.{\\catcode}, \.{\\mathcode}, \.{\\uccode}, \.{\\lccode}, and \.{\\delcode} +tables. + +@ Characters of text that have been converted to \TeX's internal form +are said to be of type |ASCII_code|, which is a subrange of the integers. + +@<Types...@>= +typedef uint8_t ASCII_code; /*eight-bit numbers*/ + +@ The original \PASCAL\ compiler was designed in the late 60s, when six-bit +character sets were common, so it did not make provision for lowercase +letters. Nowadays, of course, we need to deal with both capital and small +letters in a convenient way, especially in a program for typesetting; +so the present specification of \TeX\ has been written under the assumption +that the \PASCAL\ compiler and run-time system permit the use of text files +with more than 64 distinguishable characters. More precisely, we assume that +the character set contains at least the letters and symbols associated +with ASCII codes 040 through 0176; all of these characters are now +available on most computer terminals. + +Since we are dealing with more characters than were present in the first +\PASCAL\ compilers, we have to decide what to call the associated data +type. Some \PASCAL s use the original name |unsigned char| for the +characters in text files, even though there now are more than 64 such +characters, while other \PASCAL s consider |unsigned char| to be a 64-element +subrange of a larger data type that has some other name. + +In order to accommodate this difference, we shall use the name |text_char| +to stand for the data type of the characters that are converted to and +from |ASCII_code| when they are input and output. We shall also assume +that |text_char| consists of the elements |chr(first_text_char)| through +|chr(last_text_char)|, inclusive. The following definitions should be +adjusted if necessary. +@^system dependencies@> + +@s text_char char +@d text_char unsigned char /*the data type of characters in text files*/ +@d first_text_char 0 /*ordinal number of the smallest element of |text_char|*/ +@d last_text_char 255 /*ordinal number of the largest element of |text_char|*/ + +@<Local variables for init...@>= +int @!i; + +@ The \TeX\ processor converts between ASCII code and +the user's external character set by means of arrays |xord| and |xchr| +that are analogous to \PASCAL's |ord| and |chr| functions. + +@<Glob...@>= +static ASCII_code @!xord[256]; + /*specifies conversion of input characters*/ +static text_char @!xchr[256]; + /*specifies conversion of output characters*/ + +@ Since we are assuming that our \PASCAL\ system is able to read and +write the visible characters of standard ASCII (although not +necessarily using the ASCII codes to represent them), the following +assignment statements initialize the standard part of the |xchr| array +properly, without needing any system-dependent changes. On the other +hand, it is possible to implement \TeX\ with less complete character +sets, and in such cases it will be necessary to change something here. +@^system dependencies@> + +@<Set init...@>= +xchr[040]=' '; +xchr[041]='!'; +xchr[042]='"'; +xchr[043]='#'; +xchr[044]='$'; +xchr[045]='%'; +xchr[046]='&'; +xchr[047]='\'';@/ +xchr[050]='('; +xchr[051]=')'; +xchr[052]='*'; +xchr[053]='+'; +xchr[054]=','; +xchr[055]='-'; +xchr[056]='.'; +xchr[057]='/';@/ +xchr[060]='0'; +xchr[061]='1'; +xchr[062]='2'; +xchr[063]='3'; +xchr[064]='4'; +xchr[065]='5'; +xchr[066]='6'; +xchr[067]='7';@/ +xchr[070]='8'; +xchr[071]='9'; +xchr[072]=':'; +xchr[073]=';'; +xchr[074]='<'; +xchr[075]='='; +xchr[076]='>'; +xchr[077]='?';@/ +xchr[0100]='@@'; +xchr[0101]='A'; +xchr[0102]='B'; +xchr[0103]='C'; +xchr[0104]='D'; +xchr[0105]='E'; +xchr[0106]='F'; +xchr[0107]='G';@/ +xchr[0110]='H'; +xchr[0111]='I'; +xchr[0112]='J'; +xchr[0113]='K'; +xchr[0114]='L'; +xchr[0115]='M'; +xchr[0116]='N'; +xchr[0117]='O';@/ +xchr[0120]='P'; +xchr[0121]='Q'; +xchr[0122]='R'; +xchr[0123]='S'; +xchr[0124]='T'; +xchr[0125]='U'; +xchr[0126]='V'; +xchr[0127]='W';@/ +xchr[0130]='X'; +xchr[0131]='Y'; +xchr[0132]='Z'; +xchr[0133]='['; +xchr[0134]='\\'; +xchr[0135]=']'; +xchr[0136]='^'; +xchr[0137]='_';@/ +xchr[0140]='`'; +xchr[0141]='a'; +xchr[0142]='b'; +xchr[0143]='c'; +xchr[0144]='d'; +xchr[0145]='e'; +xchr[0146]='f'; +xchr[0147]='g';@/ +xchr[0150]='h'; +xchr[0151]='i'; +xchr[0152]='j'; +xchr[0153]='k'; +xchr[0154]='l'; +xchr[0155]='m'; +xchr[0156]='n'; +xchr[0157]='o';@/ +xchr[0160]='p'; +xchr[0161]='q'; +xchr[0162]='r'; +xchr[0163]='s'; +xchr[0164]='t'; +xchr[0165]='u'; +xchr[0166]='v'; +xchr[0167]='w';@/ +xchr[0170]='x'; +xchr[0171]='y'; +xchr[0172]='z'; +xchr[0173]='{'; +xchr[0174]='|'; +xchr[0175]='}'; +xchr[0176]='~';@/ + +@ Some of the ASCII codes without visible characters have been given symbolic +names in this program because they are used with a special meaning. + +@d null_code 00 /*ASCII code that might disappear*/ +@d carriage_return 015 /*ASCII code used at end of line*/ +@d invalid_code 0177 /*ASCII code that many systems prohibit in text files*/ + +@ The ASCII code is ``standard'' only to a certain extent, since many +computer installations have found it advantageous to have ready access +to more than 94 printing characters. Appendix~C of {\sl The \TeX book\/} +gives a complete specification of the intended correspondence between +characters and \TeX's internal representation. +@:TeXbook}{\sl The \TeX book@> + +If \TeX\ is being used +on a garden-variety \PASCAL\ for which only standard ASCII +codes will appear in the input and output files, it doesn't really matter +what codes are specified in |xchr[0 dotdot 037]|, but the safest policy is to +blank everything out by using the code shown below. + +However, other settings of |xchr| will make \TeX\ more friendly on +computers that have an extended character set, so that users can type things +like `\.^^Z' instead of `\.{\\ne}'. People with extended character sets can +assign codes arbitrarily, giving an |xchr| equivalent to whatever +characters the users of \TeX\ are allowed to have in their input files. +It is best to make the codes correspond to the intended interpretations as +shown in Appendix~C whenever possible; but this is not necessary. For +example, in countries with an alphabet of more than 26 letters, it is +usually best to map the additional letters into codes less than~040. +To get the most ``permissive'' character set, change |' '| on the +right of these assignment statements to |chr(i)|. +@^character set dependencies@> +@^system dependencies@> + +@<Set init...@>= +for (i=0; i<=037; i++) xchr[i]=chr(i); /* k\TeX\ */ +for (i=0177; i<=0377; i++) xchr[i]=chr(i); /* k\TeX\ */ + +@ The following system-independent code makes the |xord| array contain a +suitable inverse to the information in |xchr|. Note that if |xchr[i]==xchr[j]| +where |i < j < 0177|, the value of |xord[xchr[i]]| will turn out to be +|j| or more; hence, standard ASCII code numbers will be used instead of +codes below 040 in case there is a coincidence. + +@<Set init...@>= +for (i=first_text_char; i<=last_text_char; i++) xord[chr(i)]=invalid_code; +for (i=0200; i<=0377; i++) xord[xchr[i]]=i; +for (i=0; i<=0176; i++) xord[xchr[i]]=i; + +@* Input and output. +The bane of portability is the fact that different operating systems treat +input and output quite differently, perhaps because computer scientists +have not given sufficient attention to this problem. People have felt somehow +that input and output are not part of ``real'' programming. Well, it is true +that some kinds of programming are more fun than others. With existing +input/output conventions being so diverse and so messy, the only sources of +joy in such parts of the code are the rare occasions when one can find a +way to make the program a little less bad than it might have been. We have +two choices, either to attack I/O now and get it over with, or to postpone +I/O until near the end. Neither prospect is very attractive, so let's +get it over with. + +The basic operations we need to do are (1)~inputting and outputting of +text, to or from a file or the user's terminal; (2)~inputting and +outputting of eight-bit bytes, to or from a file; (3)~instructing the +operating system to initiate (``open'') or to terminate (``close'') input or +output from a specified file; (4)~testing whether the end of an input +file has been reached. + +\TeX\ needs to deal with two kinds of files. +We shall use the term |alpha_file| for a file that contains textual data, +and the term |byte_file| for a file that contains eight-bit binary information. +These two types turn out to be the same on many computers, but +sometimes there is a significant distinction, so we shall be careful to +distinguish between them. Standard protocols for transferring +such files from computer to computer, via high-speed networks, are +now becoming available to more and more communities of users. + +The program actually makes use also of a third kind of file, called a +|word_file|, when dumping and reloading base information for its own +initialization. We shall define a word file later; but it will be possible +for us to specify simple operations on word files before they are defined. + +@<Types...@>= +typedef uint8_t eight_bits; /*unsigned one-byte quantity*/ +typedef struct {@+FILE *f;@+text_char@,d;@+} alpha_file; /*files that contain textual data*/ +typedef struct {@+FILE *f;@+eight_bits@,d;@+} byte_file; /*files that contain binary data*/ + +@ Most of what we need to do with respect to input and output can be handled +by the I/O facilities that are standard in \PASCAL, i.e., the routines +called |get|, |put|, |eof|, and so on. But +standard \PASCAL\ does not allow file variables to be associated with file +names that are determined at run time, so it cannot be used to implement +\TeX; some sort of extension to \PASCAL's ordinary |reset| and |rewrite| +is crucial for our purposes. We shall assume that |name_of_file| is a variable +of an appropriate type such that the \PASCAL\ run-time system being used to +implement \TeX\ can open a file whose external name is specified by +|name_of_file|. +@^system dependencies@> + +@<Glob...@>= +unsigned char @!name_of_file0[file_name_size+1]={0}, *const @!name_of_file = @!name_of_file0-1;@;@/ + /*on some systems this may be a \&{record} variable*/ +int @!name_length;@/ /*this many characters are actually + relevant in |name_of_file| (the rest are blank)*/ + +@ k\TeX\ uses the {\tt kpathsearch} library to implement access to files. +To do so we declare \TeX's functions here and postpone the +actual implementations. These functions do not to issue their own +error messages if something goes wrong. If a file identified by +|name_of_file| cannot be found, +or if such a file cannot be opened for some other reason +(e.g., someone may already be trying to write the same file) +\TeX's file-opening procedures return |false|. +This allows \TeX\ to undertake appropriate corrective action. +@^system dependencies@> + +@p static bool a_open_in(alpha_file *f); /*open a text file for input*/ +static bool a_open_out(alpha_file *f); /*open a text file for output*/ +static bool b_open_in(byte_file *f); /*open a binary file for input*/ +static bool b_open_out(byte_file *f); /*open a binary file for output*/ +static bool w_open_in(word_file *f); /*open a word file for input*/ +#ifdef @!INIT +static bool w_open_out(word_file *f); /*open a word file for output*/ +#endif + +@ Files can be closed with the \ph\ routine `|pascal_close(f)|', which +@:PASCAL H}{\ph@> +@^system dependencies@> +should be used when all input or output with respect to |f| has been completed. +This makes |f| available to be opened again, if desired; and if |f| was used for +output, the |pascal_close| operation makes the corresponding external file appear +on the user's area, ready to be read. + +These procedures should not generate error messages if a file is +being closed before it has been successfully opened. + +@p static void a_close(alpha_file *f) /*close a text file*/ +{@+pascal_close((*f)); +} +@# +static void b_close(byte_file *f) /*close a binary file*/ +{@+pascal_close((*f)); +} +@# +static void w_close(word_file *f) /*close a word file*/ +{@+pascal_close((*f)); +} + +@ Binary input and output are done with \PASCAL's ordinary |get| and |put| +procedures, so we don't have to make any other special arrangements for +binary~I/O. Text output is also easy to do with standard \PASCAL\ routines. +The treatment of text input is more difficult, however, because +of the necessary translation to |ASCII_code| values. +\TeX's conventions should be efficient, and they should +blend nicely with the user's operating environment. + +@ Input from text files is read one line at a time, using a routine called +|input_ln|. This function is defined in terms of global variables called +|buffer|, |first|, and |last| that will be described in detail later; for +now, it suffices for us to know that |buffer| is an array of |ASCII_code| +values, and that |first| and |last| are indices into this array +representing the beginning and ending of a line of text. + +@<Glob...@>= +static ASCII_code @!buffer[buf_size+1]; /*lines of characters being read*/ +static int @!first; /*the first unused position in |buffer|*/ +static int @!last; /*end of the line just input to |buffer|*/ +static int @!max_buf_stack; /*largest index used in |buffer|*/ + +@ The |input_ln| function brings the next line of input from the specified +file into available positions of the buffer array and returns the value +|true|, unless the file has already been entirely read, in which case it +returns |false| and sets |last=first|. In general, the |ASCII_code| +numbers that represent the next line of the file are input into +|buffer[first]|, |buffer[first+1]|, \dots, |buffer[last-1]|; and the +global variable |last| is set equal to |first| plus the length of the +line. Trailing blanks are removed from the line; thus, either |last==first| +(in which case the line was entirely blank) or |buffer[last-1]!=' '|. + +An overflow error is given, however, if the normal actions of |input_ln| +would make |last >= buf_size|; this is done so that other parts of \TeX\ +can safely look at the contents of |buffer[last+1]| without overstepping +the bounds of the |buffer| array. Upon entry to |input_ln|, the condition +|first < buf_size| will always hold, so that there is always room for an +``empty'' line. + +The variable |max_buf_stack|, which is used to keep track of how large +the |buf_size| parameter must be to accommodate the present job, is +also kept up to date by |input_ln|. + +If the |bypass_eoln| parameter is |true|, |input_ln| will do a |get| +before looking at the first character of the line; this skips over +an |eoln| that was in |f.d|. The procedure does not do a |get| when it +reaches the end of the line; therefore it can be used to acquire input +from the user's terminal as well as from ordinary text files. + +Standard \PASCAL\ says that a file should have |eoln| immediately +before |eof|, but \TeX\ needs only a weaker restriction: If |eof| +occurs in the middle of a line, the system function |eoln| should return +a |true| result (even though |f.d| will be undefined). + +Since the inner loop of |input_ln| is part of \TeX's ``inner loop''---each +character of input comes in at this place---it is wise to reduce system +overhead by making use of special routines that read in an entire array +of characters at once, if such routines are available. The following +code uses standard \PASCAL\ to illustrate what needs to be done, but +finer tuning is often possible at well-developed \PASCAL\ sites. +@^inner loop@> + +@p static bool input_ln(alpha_file *f, bool @!bypass_eoln) + /*inputs the next line or returns |false|*/ +{@+int last_nonblank; /*|last| with trailing blanks removed*/ +if (bypass_eoln) if (!eof((*f))) get((*f)); + /*input the first character of the line into |f.d|*/ +last=first; /*cf.\ Matthew 19\thinspace:\thinspace30*/ +if (eof((*f))) return false; +else{@+last_nonblank=first; + while (!eoln((*f))) + {@+if (last >= max_buf_stack) + {@+max_buf_stack=last+1; + if (max_buf_stack==buf_size) + @<Report overflow of the input buffer, and abort@>; + } + buffer[last]=xord[(*f).d];get((*f));incr(last); + if (buffer[last-1]!=' ') last_nonblank=last; + } + last=last_nonblank;return true; + } +} + +@ The user's terminal acts essentially like other files of text, except +that it is used both for input and for output. When the terminal is +considered an input file, the file variable is called |term_in|, and when it +is considered an output file the file variable is |term_out|. +@^system dependencies@> + +@<Glob...@>= +static alpha_file @!term_in; /*the terminal as an input file*/ +static alpha_file @!term_out; /*the terminal as an output file*/ + +@ Here is how to open the terminal files +in \ph. The `\.{/I}' switch suppresses the first |get|. +@:PASCAL H}{\ph@> +@^system dependencies@> + +@d t_open_in term_in.f=stdin /*open the terminal for text input*/ +@d t_open_out term_out.f=stdout /*open the terminal for text output*/ + +@ Sometimes it is necessary to synchronize the input/output mixture that +happens on the user's terminal, and three system-dependent +procedures are used for this +purpose. The first of these, |update_terminal|, is called when we want +to make sure that everything we have output to the terminal so far has +actually left the computer's internal buffers and been sent. +The second, |clear_terminal|, is called when we wish to cancel any +input that the user may have typed ahead (since we are about to +issue an unexpected error message). The third, |wake_up_terminal|, +is supposed to revive the terminal if the user has disabled it by +some instruction to the operating system. The following macros show how +these operations can be specified in \ph: +@:PASCAL H}{\ph@> +@^system dependencies@> + +@d update_terminal fflush(term_out.f) /*empty the terminal output buffer*/ +@d clear_terminal fflush(term_in.f) /*clear the terminal input buffer*/ +@d wake_up_terminal do_nothing /*cancel the user's cancellation of output*/ + +@ We need a special routine to read the first line of \TeX\ input from +the user's terminal. This line is different because it is read before we +have opened the transcript file; there is sort of a ``chicken and +egg'' problem here. If the user types `\.{\\input paper}' on the first +line, or if some macro invoked by that line does such an \.{\\input}, +the transcript file will be named `\.{paper.log}'; but if no \.{\\input} +commands are performed during the first line of terminal input, the transcript +file will acquire its default name `\.{texput.log}'. (The transcript file +will not contain error messages generated by the first line before the +first \.{\\input} command.) +@.texput@> + +The first line is even more special if we are lucky enough to have an operating +system that treats \TeX\ differently from a run-of-the-mill \PASCAL\ object +program. It's nice to let the user start running a \TeX\ job by typing +a command line like `\.{tex paper}'; in such a case, \TeX\ will operate +as if the first line of input were `\.{paper}', i.e., the first line will +consist of the remainder of the command line, after the part that invoked +\TeX. + +The first line is special also because it may be read before \TeX\ has +input a format file. In such cases, normal error messages cannot yet +be given. The following code uses concepts that will be explained later. +(If the \PASCAL\ compiler does not support non-local |@!goto|\unskip, the +@^system dependencies@> +statement `|goto exit(0)|' should be replaced by something that +quietly terminates the program.) + +@<Report overflow of the input buffer, and abort@>= +if (format_ident==0) + {@+write_ln(term_out,"Buffer size exceeded!");exit(0); +@.Buffer size exceeded@> + } +else{@+cur_input.loc_field=first;cur_input.limit_field=last-1; + overflow("buffer size", buf_size); +@:TeX capacity exceeded buffer size}{\quad buffer size@> + } + +@ Different systems have different ways to get started. But regardless of +what conventions are adopted, the routine that initializes the terminal +should satisfy the following specifications: + +\yskip\textindent{1)}It should open file |term_in| for input from the + terminal. (The file |term_out| will already be open for output to the + terminal.) + +\textindent{2)}If the user has given a command line, this line should be + considered the first line of terminal input. Otherwise the + user should be prompted with `\.{**}', and the first line of input + should be whatever is typed in response. + +\textindent{3)}The first line of input, which might or might not be a + command line, should appear in locations |first| to |last-1| of the + |buffer| array. + +\textindent{4)}The global variable |loc| should be set so that the + character to be read next by \TeX\ is in |buffer[loc]|. This + character should not be blank, and we should have |loc < last|. + +\yskip\noindent(It may be necessary to prompt the user several times +before a non-blank line comes in. The prompt is `\.{**}' instead of the +later `\.*' because the meaning is slightly different: `\.{\\input}' need +not be typed immediately after~`\.{**}'.) + +@d loc cur_input.loc_field /*location of first unread character in |buffer|*/ + +@ The following program calls |input_command_line| +to retrieve a possible command line. +@^system dependencies@> + +@p static bool init_terminal(void) /*gets the terminal input started*/ +{@+ +t_open_in; +if (input_command_line()) return true; /* k\TeX\ */ +loop@+{@+wake_up_terminal;pascal_write(term_out,"**");update_terminal; +@.**@> + if (!input_ln(&term_in, true)) /*this shouldn't happen*/ + {@+write_ln(term_out); + pascal_write(term_out,"! End of file on the terminal... why?"); +@.End of file on the terminal@> + return false; + } + loc=first; + while ((loc < last)&&(buffer[loc]==' ')) incr(loc); + if (loc < last) + {@+return true; + /*return unless the line was all blank*/ + } + write_ln(term_out,"Please type the name of your input file."); + } +} + +@* String handling. +Control sequence names and diagnostic messages are variable-length strings +of eight-bit characters. Since \PASCAL\ does not have a well-developed string +mechanism, \TeX\ does all of its string processing by homegrown methods. + +Elaborate facilities for dynamic strings are not needed, so all of the +necessary operations can be handled with a simple data structure. +The array |str_pool| contains all of the (eight-bit) ASCII codes in all +of the strings, and the array |str_start| contains indices of the starting +points of each string. Strings are referred to by integer numbers, so that +string number |s| comprises the characters |str_pool[j]| for +|str_start[s] <= j < str_start[s+1]|. Additional integer variables +|pool_ptr| and |str_ptr| indicate the number of entries used so far +in |str_pool| and |str_start|, respectively; locations +|str_pool[pool_ptr]| and |str_start[str_ptr]| are +ready for the next string to be allocated. + +String numbers 0 to 255 are reserved for strings that correspond to single +ASCII characters. This is in accordance with the conventions of \.{WEB}, +@.WEB@> +which converts single-character strings into the ASCII code number of the +single character involved, while it converts other strings into integers +and builds a string pool file. Thus, when the string constant \.{"."} appears +in the program below, \.{WEB} converts it into the integer 46, which is the +ASCII code for a period, while \.{WEB} will convert a string like \.{"hello"} +into some integer greater than~255. String number 46 will presumably be the +single character `\..'; but some ASCII codes have no standard visible +representation, and \TeX\ sometimes needs to be able to print an arbitrary +ASCII character, so the first 256 strings are used to specify exactly what +should be printed for each of the 256 possibilities. + +Elements of the |str_pool| array must be ASCII codes that can actually +be printed; i.e., they must have an |xchr| equivalent in the local +character set. (This restriction applies only to preloaded strings, +not to those generated dynamically by the user.) + +Some \PASCAL\ compilers won't pack integers into a single byte unless the +integers lie in the range |-128 dotdot 127|. To accommodate such systems +we access the string pool only via macros that can easily be redefined. +@^system dependencies@> + +@d si(A) A /*convert from |ASCII_code| to |packed_ASCII_code|*/ +@d so(A) A /*convert from |packed_ASCII_code| to |ASCII_code|*/ + +@<Types...@>= +typedef int32_t pool_pointer; /*for variables that point into |str_pool|*/ +typedef int32_t str_number; /*for variables that point into |str_start|*/ +typedef uint8_t packed_ASCII_code; /*elements of |str_pool| array*/ + +@ @<Glob...@>= +packed_ASCII_code @!str_pool[pool_size+1]; /*the characters*/ +pool_pointer @!str_start[max_strings+1]; /*the starting pointers*/ +static pool_pointer @!pool_ptr; /*first unused position in |str_pool|*/ +static str_number @!str_ptr; /*number of the current string being created*/ +static pool_pointer @!init_pool_ptr; /*the starting value of |pool_ptr|*/ +static str_number @!init_str_ptr; /*the starting value of |str_ptr|*/ + +@ Several of the elementary string operations are performed using \.{WEB} +macros instead of \PASCAL\ procedures, because many of the +operations are done quite frequently and we want to avoid the +overhead of procedure calls. For example, here is +a simple macro that computes the length of a string. +@.WEB@> + +@d length(A) (str_start[A+1]-str_start[A]) /*the number of characters + in string number \#*/ + +@ The length of the current string is called |cur_length|: + +@d cur_length (pool_ptr-str_start[str_ptr]) + +@ Strings are created by appending character codes to |str_pool|. +The |append_char| macro, defined here, does not check to see if the +value of |pool_ptr| has gotten too high; this test is supposed to be +made before |append_char| is used. There is also a |flush_char| +macro, which erases the last character appended. + +To test if there is room to append |l| more characters to |str_pool|, +we shall write |str_room(l)|, which aborts \TeX\ and gives an +apologetic error message if there isn't enough room. + +@d append_char(A) /*put |ASCII_code| \# at the end of |str_pool|*/ +{@+str_pool[pool_ptr]=si(A);incr(pool_ptr); +} +@d flush_char decr(pool_ptr) /*forget the last character in the pool*/ +@d str_room(A) /*make sure that the pool hasn't overflowed*/ + {@+if (pool_ptr+A > pool_size) + overflow("pool size", pool_size-init_pool_ptr); +@:TeX capacity exceeded pool size}{\quad pool size@> + } + +@ Once a sequence of characters has been appended to |str_pool|, it +officially becomes a string when the function |make_string| is called. +This function returns the identification number of the new string as its +value. + +@p static str_number make_string(void) /*current string enters the pool*/ +{@+if (str_ptr==max_strings) + overflow("number of strings", max_strings-init_str_ptr); +@:TeX capacity exceeded number of strings}{\quad number of strings@> +incr(str_ptr);str_start[str_ptr]=pool_ptr; +return str_ptr-1; +} + +@ To destroy the most recently made string, we say |flush_string|. + +@d flush_string {@+decr(str_ptr);pool_ptr=str_start[str_ptr]; + } + +@ The following subroutine compares string |s| with another string of the +same length that appears in |buffer| starting at position |k|; +the result is |true| if and only if the strings are equal. +Empirical tests indicate that |str_eq_buf| is used in such a way that +it tends to return |true| about 80 percent of the time. + +@p static bool str_eq_buf(str_number @!s, int @!k) + /*test equality of strings*/ +{@+ /*loop exit*/ +pool_pointer j; /*running index*/ +bool @!result; /*result of comparison*/ +j=str_start[s]; +while (j < str_start[s+1]) + {@+if (so(str_pool[j])!=buffer[k]) + {@+result=false;goto not_found; + } + incr(j);incr(k); + } +result=true; +not_found: return result; +} + +@ Here is a similar routine, but it compares two strings in the string pool, +and it does not assume that they have the same length. + +@p static bool strn_eq_str(str_number @!s, str_number @!t) + /*test equality of strings*/ +{@+ /*loop exit*/ +pool_pointer j, @!k; /*running indices*/ +bool @!result; /*result of comparison*/ +result=false; +if (length(s)!=length(t)) goto not_found; +j=str_start[s];k=str_start[t]; +while (j < str_start[s+1]) + {@+if (str_pool[j]!=str_pool[k]) goto not_found; + incr(j);incr(k); + } +result=true; +not_found: return result; +} + +static bool str_eq_str(str_number @!s, char *@!t) + /*test equality of strings*/ +{@+int j, @!k; /*running indices*/ +if (length(s)!=(int)strlen(t)) return false; +j=str_start[s];k=0; +while (j < str_start[s+1]) + if (str_pool[j++]!=t[k++]) return false; +return true; +} + +@ The initial values of |str_pool|, |str_start|, |pool_ptr|, +and |str_ptr| are computed by the \.{INITEX} program, based in part +on the information that \.{WEB} has output while processing \TeX. +@.INITEX@> +@^string pool@> + +@p +static void get_strings_started(void) /*initializes the string pool*/ +{@+ +int k, @!l; /*small indices or counters*/ +pool_ptr=0;str_ptr=0;str_start[0]=0; +@<Make the first 256 strings@>; +@<Add the empty string to the string pool@>; +} + +@ @d app_lc_hex(A) l=A; + if (l < 10) append_char(l+'0')@;@+else append_char(l-10+'a') + +@<Make the first 256...@>= +for (k=0; k<=255; k++) + {@+if ((@<Character |k| cannot be printed@>)) + {@+append_char('^');append_char('^'); + if (k < 0100) append_char(k+0100)@; + else if (k < 0200) append_char(k-0100)@; + else{@+app_lc_hex(k/16);app_lc_hex(k%16); + } + } + else append_char(k); + make_string(); + } + +@ The first 128 strings will contain 95 standard ASCII characters, and the +other 33 characters will be printed in three-symbol form like `\.{\^\^A}' +unless a system-dependent change is made here. Installations that have +an extended character set, where for example |xchr[032]==@t\.{\'^^Z\'}@>|, +would like string 032 to be the single character 032 instead of the +three characters 0136, 0136, 0132 (\.{\^\^Z}). On the other hand, +even people with an extended character set will want to represent string +015 by \.{\^\^M}, since 015 is |carriage_return|; the idea is to +produce visible strings instead of tabs or line-feeds or carriage-returns +or bell-rings or characters that are treated anomalously in text files. + +Unprintable characters of codes 128--255 are, similarly, rendered +\.{\^\^80}--\.{\^\^ff}. + +The boolean expression defined here should be |true| unless \TeX\ +internal code number~|k| corresponds to a non-troublesome visible +symbol in the local character set. An appropriate formula for the +extended character set recommended in {\sl The \TeX book\/} would, for +example, be `|k in[0, 010 dotdot 012, 014, 015, 033, 0177 dotdot 0377]|'. +If character |k| cannot be printed, and |k < 0200|, then character |k+0100| or +|k-0100| must be printable; moreover, ASCII codes |[041 dotdot 046, +060 dotdot 071, 0136, 0141 dotdot 0146, 0160 dotdot 0171]| must be printable. +Thus, at least 81 printable characters are needed. +@:TeXbook}{\sl The \TeX book@> +@^character set dependencies@> +@^system dependencies@> + +@<Character |k| cannot be printed@>= + (k < ' ')||(k > '~') + +@ The |pool_file| variable is no longer needed and has been removed. + +@ Instead of reading the other strings from the \.{TEX.POOL} file, +it is sufficient here to add the empty string. +@<Add the empty string to the string pool@>= +make_string(); + +@ Without a string pool file there is no need for a pool check sum either. +But this is a convenient place to define the function |s_no| that will +add literal strings to the string pool at runtime, thereby obtaining their +string number. + +@p int s_no(const char *str) +{@+ + if (str[0]==0) return empty_string; + if (str[1]==0) return str[0]; + str_room(strlen(str)); + while (*str!=0) append_char(*str++); + return make_string(); +} + +@* On-line and off-line printing. +Messages that are sent to a user's terminal and to the transcript-log file +are produced by several `|print|' procedures. These procedures will +direct their output to a variety of places, based on the setting of +the global variable |selector|, which has the following possible +values: + +\yskip +\hang |term_and_log|, the normal setting, prints on the terminal and on the + transcript file. + +\hang |log_only|, prints only on the transcript file. + +\hang |term_only|, prints only on the terminal. + +\hang |no_print|, doesn't print at all. This is used only in rare cases + before the transcript file is open. + +\hang |pseudo|, puts output into a cyclic buffer that is used + by the |show_context| routine; when we get to that routine we shall discuss + the reasoning behind this curious mode. + +\hang |new_string|, appends the output to the current string in the + string pool. + +\hang 0 to 15, prints on one of the sixteen files for \.{\\write} output. + +\yskip +\noindent The symbolic names `|term_and_log|', etc., have been assigned +numeric codes that satisfy the convenient relations |no_print+1==term_only|, +|no_print+2==log_only|, |term_only+2==log_only+1==term_and_log|. + +Three additional global variables, |tally| and |term_offset| and +|file_offset|, record the number of characters that have been printed +since they were most recently cleared to zero. We use |tally| to record +the length of (possibly very long) stretches of printing; |term_offset| +and |file_offset|, on the other hand, keep track of how many characters +have appeared so far on the current line that has been output to the +terminal or to the transcript file, respectively. + +@d no_print 16 /*|selector| setting that makes data disappear*/ +@d term_only 17 /*printing is destined for the terminal only*/ +@d log_only 18 /*printing is destined for the transcript file only*/ +@d term_and_log 19 /*normal |selector| setting*/ +@d pseudo 20 /*special |selector| setting for |show_context|*/ +@d new_string 21 /*printing is deflected to the string pool*/ +@d max_selector 21 /*highest selector setting*/ + +@<Glob...@>= +static alpha_file @!log_file; /*transcript of \TeX\ session*/ +static int @!selector; /*where to print a message*/ +static int8_t @!dig[23]; /*digits in a number being output*/ +static int @!tally; /*the number of characters recently printed*/ +static int @!term_offset; + /*the number of characters on the current terminal line*/ +static int @!file_offset; + /*the number of characters on the current file line*/ +static ASCII_code @!trick_buf[error_line+1]; /*circular buffer for + pseudoprinting*/ +static int @!trick_count; /*threshold for pseudoprinting, explained later*/ +static int @!first_count; /*another variable for pseudoprinting*/ + +@ @<Initialize the output routines@>= +selector=term_only;tally=0;term_offset=0;file_offset=0; + +@ Macro abbreviations for output to the terminal and to the log file are +defined here for convenience. Some systems need special conventions +for terminal output, and it is possible to adhere to those conventions +by changing |wterm|, |wterm_ln|, and |wterm_cr| in this section. +@^system dependencies@> + +@<Basic printing procedures@>= +#define put(F) @[fwrite(&((F).d),sizeof((F).d),1,(F).f)@] +#define get(F) @[fread(&((F).d),sizeof((F).d),1,(F).f)@] + +#define pascal_close(F) @[fclose((F).f)@] +#define eof(F) @[feof((F).f)@] +#define eoln(F) @[((F).d=='\n'||eof(F))@] +#define erstat(F) @[((F).f==NULL?-1:ferror((F).f))@] + +#define pascal_read(F,X) @[((X)=(F).d,get(F))@] +#define read_ln(F) @[do get(F); while (!eoln(F))@] + +#define pascal_write(F, FMT,...) @[fprintf(F.f,FMT,## __VA_ARGS__)@] +#define write_ln(F,...) @[pascal_write(F,__VA_ARGS__"\n")@] + +#define wterm(FMT,...) @[pascal_write(term_out,FMT, ## __VA_ARGS__)@] +#define wterm_ln(FMT,...) @[wterm(FMT "\n", ## __VA_ARGS__)@] +#define wterm_cr @[pascal_write(term_out,"\n")@] +#define wlog(FMT, ...) @[pascal_write(log_file,FMT, ## __VA_ARGS__)@] +#define wlog_ln(FMT, ...) @[wlog(FMT "\n", ## __VA_ARGS__)@] +#define wlog_cr @[pascal_write(log_file,"\n")@] + +@ To end a line of text output, we call |print_ln|. + +@<Basic print...@>= +void print_ln(void) /*prints an end-of-line*/ +{@+switch (selector) { +case term_and_log: {@+wterm_cr;wlog_cr; + term_offset=0;file_offset=0; + } @+break; +case log_only: {@+wlog_cr;file_offset=0; + } @+break; +case term_only: {@+wterm_cr;term_offset=0; + } @+break; +case no_print: case pseudo: case new_string: do_nothing;@+break; +default:write_ln(write_file[selector]); +} @/ +} /*|tally| is not affected*/ + +@ The |print_char| procedure sends one character to the desired destination, +using the |xchr| array to map it into an external character compatible with +|input_ln|. All printing comes through |print_ln| or |print_char|. + +@<Basic printing...@>= +void print_char(ASCII_code @!s) /*prints a single character*/ +{@+ +if (@<Character |s| is the current new-line character@>) + if (selector < pseudo) + {@+print_ln();return; + } +switch (selector) { +case term_and_log: {@+wterm("%c",xchr[s]);wlog("%c",xchr[s]); + incr(term_offset);incr(file_offset); + if (term_offset==max_print_line) + {@+wterm_cr;term_offset=0; + } + if (file_offset==max_print_line) + {@+wlog_cr;file_offset=0; + } + } @+break; +case log_only: {@+wlog("%c",xchr[s]);incr(file_offset); + if (file_offset==max_print_line) print_ln(); + } @+break; +case term_only: {@+wterm("%c",xchr[s]);incr(term_offset); + if (term_offset==max_print_line) print_ln(); + } @+break; +case no_print: do_nothing;@+break; +case pseudo: if (tally < trick_count) trick_buf[tally%error_line]=s;@+break; +case new_string: {@+if (pool_ptr < pool_size) append_char(s); + } @+break; /*we drop characters if the string space is full*/ +default:pascal_write(write_file[selector],"%c", xchr[s]); +} @/ +incr(tally); +} + +@ An entire string is output by calling |print|. Note that if we are outputting +the single standard ASCII character \.c, we could call |print('c')|, since +|'c'==99| is the number of a single-character string, as explained above. But +|print_char('c')| is quicker, so \TeX\ goes directly to the |print_char| +routine when it knows that this is safe. (The present implementation +assumes that it is always safe to print a visible ASCII character.) +@^system dependencies@> + +@<Basic print...@>= +void print(char *s) /* the simple version */ +{ while (*s!=0) print_char(*s++);@+ +} + +static void printn(int @!s) /*prints string |s|*/ +{@+ +pool_pointer j; /*current character code position*/ +int @!nl; /*new-line character to restore*/ +if (s >= str_ptr) {print("???"); return;}/*this can't happen*/ +@.???@> +else if (s < 256) + if (s < 0) { print("???");return; } /*can't happen*/ + else{@+if (selector > pseudo) + {@+print_char(s);return; /*internal strings are not expanded*/ + } + if ((@<Character |s| is the current new-line character@>)) + if (selector < pseudo) + {@+print_ln();return; + } + nl=new_line_char;new_line_char=-1; + /*temporarily disable new-line character*/ + j=str_start[s]; + while (j < str_start[s+1]) + {@+print_char(so(str_pool[j]));incr(j); + } + new_line_char=nl;return; + } +j=str_start[s]; +while (j < str_start[s+1]) + {@+print_char(so(str_pool[j]));incr(j); + } +} + +@ Control sequence names, file names, and strings constructed with +\.{\\string} might contain |ASCII_code| values that can't +be printed using |print_char|. Therefore we use |slow_print| for them: + +@<Basic print...@>= +static void slow_print(int @!s) /*prints string |s|*/ +{@+pool_pointer j; /*current character code position*/ +if ((s >= str_ptr)||(s < 256)) printn(s); +else{@+j=str_start[s]; + while (j < str_start[s+1]) + {@+printn(so(str_pool[j]));incr(j); + } + } +} + +@ Here is the very first thing that \TeX\ prints: a headline that identifies +the version number and format package. The |term_offset| variable is temporarily +incorrect, but the discrepancy is not serious since we assume that the banner +and format identifier together will occupy at most |max_print_line| +character positions. + +k\TeX, according to the conventions of \TeX\ Live, + prints the |dump_name| if no format identifier is known. +@<Initialize the output...@>= +wterm("%s",banner); +if (format_ident==0) wterm_ln(" (preloaded format=%s)", dump_name); +else{@+slow_print(format_ident);print_ln(); + } +update_terminal; + +@ The procedure |print_nl| is like |print|, but it makes sure that the +string appears at the beginning of a new line. + +@<Basic print...@>= +void print_nl(char *@!s) /*prints string |s| at beginning of line*/ +{@+if (((term_offset > 0)&&(odd(selector)))||@| + ((file_offset > 0)&&(selector >= log_only))) print_ln(); +print(s); +} + +@ The procedure |print_esc| prints a string that is preceded by +the user's escape character (which is usually a backslash). + +@<Basic print...@>= +static void printn_esc(str_number @!s) /*prints escape character, then |s|*/ +{@+int c; /*the escape character code*/ +@<Set variable |c| to the current escape character@>; +if (c >= 0) if (c < 256) printn(c); +slow_print(s); +} + +static void print_esc(char *@!s) /*the fast way*/ +{@+int c; /*the escape character code*/ +@<Set variable |c| to the current escape character@>; +if (c >= 0) if (c < 256) printn(c); +print(s); +} + +@ An array of digits in the range |0 dotdot 15| is printed by |print_the_digs|. + +@<Basic print...@>= +static void print_the_digs(eight_bits @!k) + /*prints |dig[k-1]|$\,\ldots\,$|dig[0]|*/ +{@+while (k > 0) + {@+decr(k); + if (dig[k] < 10) print_char('0'+dig[k]); + else print_char('A'-10+dig[k]); + } +} + +@ The following procedure, which prints out the decimal representation of a +given integer |n|, has been written carefully so that it works properly +if |n==0| or if |(-n)| would cause overflow. It does not apply |%| or |/| +to negative arguments, since such operations are not implemented consistently +by all \PASCAL\ compilers. + +@<Basic print...@>= +void print_int(int @!n) /*prints an integer in decimal form*/ +{@+int k; /*index to current digit; we assume that $|n|<10^{23}$*/ +int @!m; /*used to negate |n| in possibly dangerous cases*/ +k=0; +if (n < 0) + {@+print_char('-'); + if (n > -100000000) negate(n); + else{@+m=-1-n;n=m/10;m=(m%10)+1;k=1; + if (m < 10) dig[0]=m; + else{@+dig[0]=0;incr(n); + } + } + } +@/do@+{dig[k]=n%10;n=n/10;incr(k); +}@+ while (!(n==0)); +print_the_digs(k); +} + +@ Here is a trivial procedure to print two digits; it is usually called with +a parameter in the range |0 <= n <= 99|. + +@p static void print_two(int @!n) /*prints two least significant digits*/ +{@+n=abs(n)%100;print_char('0'+(n/10)); +print_char('0'+(n%10)); +} + +@ Hexadecimal printing of nonnegative integers is accomplished by |print_hex|. + +@p static void print_hex(int @!n) + /*prints a positive integer in hexadecimal form*/ +{@+int k; /*index to current digit; we assume that $0\le n<16^{22}$*/ +k=0;print_char('"'); +@/do@+{dig[k]=n%16;n=n/16;incr(k); +}@+ while (!(n==0)); +print_the_digs(k); +} + +@ Old versions of \TeX\ needed a procedure called |print_ASCII| whose function +is now subsumed by |print|. We retain the old name here as a possible aid to +future software arch\ae ologists. + +@d print_ASCII printn + +@ Roman numerals are produced by the |print_roman_int| routine. Readers +who like puzzles might enjoy trying to figure out how this tricky code +works; therefore no explanation will be given. Notice that 1990 yields +\.{mcmxc}, not \.{mxm}. + +@p static void print_roman_int(int @!n) +{@+ +pool_pointer j, @!k; /*mysterious indices into |mystery|*/ +nonnegative_integer @!u, @!v; /*mysterious numbers*/ +const char mystery[] ="m2d5c2l5x2v5i"; +j=0;v=1000; +loop@+{@+while (n >= v) + {@+print_char(so(mystery[j]));n=n-v; + } + if (n <= 0) return; /*nonpositive input produces no output*/ + k=j+2;u=v/(so(mystery[k-1])-'0'); + if (mystery[k-1]==si('2')) + {@+k=k+2;u=u/(so(mystery[k-1])-'0'); + } + if (n+u >= v) + {@+print_char(so(mystery[k]));n=n+u; + } + else{@+j=j+2;v=v/(so(mystery[j-1])-'0'); + } + } +} + +@ The |print| subroutine will not print a string that is still being +created. The following procedure will. + +@p static void print_current_string(void) /*prints a yet-unmade string*/ +{@+pool_pointer j; /*points to current character code*/ +j=str_start[str_ptr]; +while (j < pool_ptr) + {@+print_char(so(str_pool[j]));incr(j); + } +} + +@ Here is a procedure that asks the user to type a line of input, +assuming that the |selector| setting is either |term_only| or |term_and_log|. +The input is placed into locations |first| through |last-1| of the +|buffer| array, and echoed on the transcript file if appropriate. + +This procedure is never called when |interaction < scroll_mode|. + +@d prompt_input(A) {@+wake_up_terminal;print(A);term_input(); + } /*prints a string and gets a line of input*/ + +@p static void term_input(void) /*gets a line from the terminal*/ +{@+int k; /*index into |buffer|*/ +update_terminal; /*now the user sees the prompt for sure*/ +if (!input_ln(&term_in, true)) fatal_error("End of file on the terminal!"); +@.End of file on the terminal@> +term_offset=0; /*the user's line ended with \<\rm return>*/ +decr(selector); /*prepare to echo the input*/ +if (last!=first) for (k=first; k<=last-1; k++) printn(buffer[k]); +print_ln();incr(selector); /*restore previous status*/ +} + +@* Reporting errors. +When something anomalous is detected, \TeX\ typically does something like this: +$$\vbox{\halign{#\hfil\cr +|print_err("Something anomalous has been detected");|\cr +|help3("This is the first line of my offer to help.")|\cr +|("This is the second line. I'm trying to")|\cr +|("explain the best way for you to proceed.");|\cr +|error;|\cr}}$$ +A two-line help message would be given using |help2|, etc.; these informal +helps should use simple vocabulary that complements the words used in the +official error message that was printed. (Outside the U.S.A., the help +messages should preferably be translated into the local vernacular. Each +line of help is at most 60 characters long, in the present implementation, +so that |max_print_line| will not be exceeded.) + +The |print_err| procedure supplies a `\.!' before the official message, +and makes sure that the terminal is awake if a stop is going to occur. +The |error| procedure supplies a `\..' after the official message, then it +shows the location of the error; and if |interaction==error_stop_mode|, +it also enters into a dialog with the user, during which time the help +message may be printed. +@^system dependencies@> + +@<Error handling...@>= +void print_err(char *s) +{@+if (interaction==error_stop_mode) wake_up_terminal; + if (filelineerrorstylep) print_file_line(); /* k\TeX\ */ + else print_nl("! "); + print(s); +} + +@ The global variable |interaction| has four settings, representing increasing +amounts of user interaction: + +@d batch_mode 0 /*omits all stops and omits terminal output*/ +@d nonstop_mode 1 /*omits all stops*/ +@d scroll_mode 2 /*omits error stops*/ +@d error_stop_mode 3 /*stops at every opportunity to interact*/ + +@<Glob...@>= +int @!interaction; /*current level of interaction*/ + +@ @<Set init...@>=interaction=error_stop_mode; + +@ \TeX\ is careful not to call |error| when the print |selector| setting +might be unusual. The only possible values of |selector| at the time of +error messages are + +\yskip\hang|no_print| (when |interaction==batch_mode| + and |log_file| not yet open); + +\hang|term_only| (when |interaction > batch_mode| and |log_file| not yet open); + +\hang|log_only| (when |interaction==batch_mode| and |log_file| is open); + +\hang|term_and_log| (when |interaction > batch_mode| and |log_file| is open). + +@<Initialize the print |selector| based on |interaction|@>= +if (interaction==batch_mode) selector=no_print;@+else selector=term_only + +@ A global variable |deletions_allowed| is set |false| if the |get_next| +routine is active when |error| is called; this ensures that |get_next| +and related routines like |get_token| will never be called recursively. +A similar interlock is provided by |set_box_allowed|. +@^recursion@> + +The global variable |history| records the worst level of error that +has been detected. It has four possible values: |spotless|, |warning_issued|, +|error_message_issued|, and |fatal_error_stop|. + +Another global variable, |error_count|, is increased by one when an +|error| occurs without an interactive dialog, and it is reset to zero at +the end of every paragraph. If |error_count| reaches 100, \TeX\ decides +that there is no point in continuing further. + +@d spotless 0 /*|history| value when nothing has been amiss yet*/ +@d warning_issued 1 /*|history| value when |begin_diagnostic| has been called*/ +@d error_message_issued 2 /*|history| value when |error| has been called*/ +@d fatal_error_stop 3 /*|history| value when termination was premature*/ + +@<Glob...@>= +static bool @!deletions_allowed; /*is it safe for |error| to call |get_token|?*/ +static bool @!set_box_allowed; /*is it safe to do a \.{\\setbox} assignment?*/ +static int @!history; /*has the source input been clean so far?*/ +static int @!error_count; /*the number of scrolled errors since the + last paragraph ended*/ + +@ The value of |history| is initially |fatal_error_stop|, but it will +be changed to |spotless| if \TeX\ survives the initialization process. + +@<Set init...@>= +deletions_allowed=true;set_box_allowed=true; +error_count=0; /*|history| is initialized elsewhere*/ + +@ Since errors can be detected almost anywhere in \TeX, we want to declare the +error procedures near the beginning of the program. But the error procedures +in turn use some other procedures, which need to be declared |forward| +before we get to |error| itself. + +It is possible for |error| to be called recursively if some error arises +when |get_token| is being used to delete a token, and/or if some fatal error +occurs while \TeX\ is trying to fix a non-fatal one. But such recursion +@^recursion@> +is never more than two levels deep. + +@<Error handling...@>= +static void normalize_selector(void);@/ +static void get_token(void);@/ +static void term_input(void);@/ +static void show_context(void);@/ +static void begin_file_reading(void);@/ +void open_log_file(void);@/ +static void close_files_and_terminate(void);@/ +static void clear_for_error_prompt(void);@/ +static void give_err_help(void);@/ +#ifdef @!DEBUG +static void debug_help(void); +#else +#define debug_help() do_nothing +#endif + +@ Individual lines of help are recorded in the array |help_line|, which +contains entries in positions |0 dotdot(help_ptr-1)|. They should be printed +in reverse order, i.e., with |help_line[0]| appearing last. + +@d hlp1(A) help_line[0]=A;@+} +@d hlp2(A, B) help_line[1]=A;help_line[0]=B;@+} +@d hlp3(A, B, C) help_line[2]=A;help_line[1]=B;help_line[0]=C;@+} +@d hlp4(A, B, C, D) help_line[3]=A;help_line[2]=B;help_line[1]=C;help_line[0]=D;@+} +@d hlp5(A, B, C, D, E) help_line[4]=A;help_line[3]=B;help_line[2]=C;help_line[1]=D;help_line[0]=E;@+} +@d hlp6(A, B, C, D, E, F) help_line[5]=A;help_line[4]=B;help_line[3]=C;help_line[2]=D;help_line[1]=E;help_line[0]=F;@+} +@d help0 help_ptr=0 /*sometimes there might be no help*/ +@d help1(A) @+{@+help_ptr=1;hlp1(A) /*use this with one help line*/ +@d help2(A, B) @+{@+help_ptr=2;hlp2(A, B) /*use this with two help lines*/ +@d help3(A, B, C) @+{@+help_ptr=3;hlp3(A, B, C) /*use this with three help lines*/ +@d help4(A, B, C, D) @+{@+help_ptr=4;hlp4(A, B, C, D) /*use this with four help lines*/ +@d help5(A, B, C, D, E) @+{@+help_ptr=5;hlp5(A, B, C, D, E) /*use this with five help lines*/ +@d help6(A, B, C, D, E, F) @+{@+help_ptr=6;hlp6(A, B, C, D, E, F) /*use this with six help lines*/ + +@<Glob...@>= +static char *@!help_line[6]; /*helps for the next |error|*/ +static int @!help_ptr; /*the number of help lines present*/ +static bool @!use_err_help; /*should the |err_help| list be shown?*/ + +@ @<Set init...@>= +help_ptr=0;use_err_help=false; + +@ The |jump_out| procedure just cuts across all active procedure levels and +goes to |end_of_TEX|. This is the only nontrivial |@!goto| statement in the +whole program. It is used when there is no recovery from a particular error. + +Some \PASCAL\ compilers do not implement non-local |goto| statements. +@^system dependencies@> +In such cases the body of |jump_out| should simply be +`|close_files_and_terminate|;\thinspace' followed by a call on some system +procedure that quietly terminates the program. + +@<Error hand...@>= +static void jump_out(void) +{@+ close_files_and_terminate(); exit(0); +} + +@ Here now is the general |error| routine. + +@<Error hand...@>= +static void error(void) /*completes the job of error reporting*/ +{@+ +ASCII_code c; /*what the user types*/ +int @!s1, @!s2, @!s3, @!s4; + /*used to save global variables when deleting tokens*/ +if (history < error_message_issued) history=error_message_issued; +print_char('.');show_context(); +if (interaction==error_stop_mode) @<Get user's advice and |return|@>; +incr(error_count); +if (error_count==100) + {@+print_nl("(That makes 100 errors; please try again.)"); +@.That makes 100 errors...@> + history=fatal_error_stop;jump_out(); + } +@<Put help message on the transcript file@>; +} + +@ @<Get user's advice...@>= +loop@+{@+resume: clear_for_error_prompt();prompt_input("? "); +@.?\relax@> + if (last==first) return; + c=buffer[first]; + if (c >= 'a') c=c+'A'-'a'; /*convert to uppercase*/ + @<Interpret code |c| and |return| if done@>; + } + +@ It is desirable to provide an `\.E' option here that gives the user +an easy way to return from \TeX\ to the system editor, with the offending +line ready to be edited. But such an extension requires some system +wizardry, so the present implementation simply types out the name of the +file that should be +edited and the relevant line number. +@^system dependencies@> + +There is a secret `\.D' option available when the debugging routines haven't +been commented~out. +@^debugging@> + +@<Interpret code |c| and |return| if done@>= +switch (c) { +case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': if (deletions_allowed) + @<Delete \(c)|c-"0"| tokens and |goto continue|@>@;@+break; +@t\4\4@>@; +#ifdef @!DEBUG +case 'D': {@+debug_help();goto resume;@+} +#endif +case 'E': if (base_ptr > 0) + {@+print_nl("You want to edit file "); +@.You want to edit file x@> + slow_print(input_stack[base_ptr].name_field); + print(" at line ");print_int(line); + interaction=scroll_mode;jump_out(); + } @+break; +case 'H': @<Print the help information and |goto continue|@>@; +case 'I': @<Introduce new material from the terminal and |return|@>@; +case 'Q': case 'R': case 'S': @<Change the interaction level and |return|@>@; +case 'X': {@+interaction=scroll_mode;jump_out(); + } @+break; +default:do_nothing; +} @/ +@<Print the menu of available options@>@; + +@ @<Print the menu...@>= +{@+print("Type <return> to proceed, S to scroll future error messages,");@/ +@.Type <return> to proceed...@> +print_nl("R to run without stopping, Q to run quietly,");@/ +print_nl("I to insert something, "); +if (base_ptr > 0) print("E to edit your file,"); +if (deletions_allowed) + print_nl("1 or ... or 9 to ignore the next 1 to 9 tokens of input,"); +print_nl("H for help, X to quit."); +} + +@ Here the author of \TeX\ apologizes for making use of the numerical +relation between |'Q'|, |'R'|, |'S'|, and the desired interaction settings +|batch_mode|, |nonstop_mode|, |scroll_mode|. +@^Knuth, Donald Ervin@> + +@<Change the interaction...@>= +{@+error_count=0;interaction=batch_mode+c-'Q'; +print("OK, entering "); +switch (c) { +case 'Q': {@+print_esc("batchmode");decr(selector); + } @+break; +case 'R': print_esc("nonstopmode");@+break; +case 'S': print_esc("scrollmode"); +} /*there are no other cases*/ +print("...");print_ln();update_terminal;return; +} + +@ When the following code is executed, |buffer[(first+1)dotdot(last-1)]| may +contain the material inserted by the user; otherwise another prompt will +be given. In order to understand this part of the program fully, you need +to be familiar with \TeX's input stacks. + +@<Introduce new material...@>= +{@+begin_file_reading(); /*enter a new syntactic level for terminal input*/ + /*now |state==mid_line|, so an initial blank space will count as a blank*/ +if (last > first+1) + {@+loc=first+1;buffer[first]=' '; + } +else{@+prompt_input("insert>");loc=first; +@.insert>@> + } +first=last; +cur_input.limit_field=last-1; /*no |end_line_char| ends this line*/ +return; +} + +@ We allow deletion of up to 99 tokens at a time. + +@<Delete \(c)|c-"0"| tokens...@>= +{@+s1=cur_tok;s2=cur_cmd;s3=cur_chr;s4=align_state; +align_state=1000000;OK_to_interrupt=false; +if ((last > first+1)&&(buffer[first+1] >= '0')&&(buffer[first+1] <= '9')) + c=c*10+buffer[first+1]-'0'*11; +else c=c-'0'; +while (c > 0) + {@+get_token(); /*one-level recursive call of |error| is possible*/ + decr(c); + } +cur_tok=s1;cur_cmd=s2;cur_chr=s3;align_state=s4;OK_to_interrupt=true; +help2("I have just deleted some text, as you asked.",@/ +"You can now delete more, or insert, or whatever."); +show_context();goto resume; +} + +@ @<Print the help info...@>= +{@+if (use_err_help) + {@+give_err_help();use_err_help=false; + } +else{@+if (help_ptr==0) + help2("Sorry, I don't know how to help in this situation.",@/ + @t\kern1em@>"Maybe you should try asking a human?"); + @/do@+{decr(help_ptr);print(help_line[help_ptr]);print_ln(); + }@+ while (!(help_ptr==0)); + } +help4("Sorry, I already gave what help I could...",@/ + "Maybe you should try asking a human?",@/ + "An error might have occurred before I noticed any problems.",@/ + "``If all else fails, read the instructions.'");@/ +goto resume; +} + +@ @<Put help message on the transcript file@>= +if (interaction > batch_mode) decr(selector); /*avoid terminal output*/ +if (use_err_help) + {@+print_ln();give_err_help(); + } +else while (help_ptr > 0) + {@+decr(help_ptr);print_nl(help_line[help_ptr]); + } +print_ln(); +if (interaction > batch_mode) incr(selector); /*re-enable terminal output*/ +print_ln() + +@ A dozen or so error messages end with a parenthesized integer, so we +save a teeny bit of program space by declaring the following procedure: + +@p static void int_error(int @!n) +{@+print(" (");print_int(n);print_char(')');error(); +} + +@ In anomalous cases, the print selector might be in an unknown state; +the following subroutine is called to fix things just enough to keep +running a bit longer. + +@p static void normalize_selector(void) +{@+if (log_opened) selector=term_and_log; +else selector=term_only; +if (job_name==0) open_log_file(); +if (interaction==batch_mode) decr(selector); +} + +@ The following procedure prints \TeX's last words before dying. + +@d succumb {@+if (interaction==error_stop_mode) + interaction=scroll_mode; /*no more interaction*/ + if (log_opened) error(); + if (interaction > batch_mode) debug_help(); + history=fatal_error_stop;jump_out(); /*irrecoverable error*/ + } + +@<Error hand...@>= +void fatal_error(char *@!s) /*prints |s|, and that's it*/ +{@+normalize_selector();@/ +print_err("Emergency stop");help1(s);succumb; +@.Emergency stop@> +} + +@ Here is the most dreaded error message. + +@<Error hand...@>= +void overflow(char *@!s, int @!n) /*stop due to finiteness*/ +{@+normalize_selector(); +print_err("TeX capacity exceeded, sorry ["); +@.TeX capacity exceeded ...@> +print(s);print_char('=');print_int(n);print_char(']'); +help2("If you really absolutely need more capacity,",@/ + "you can ask a wizard to enlarge me."); +succumb; +} + +@ The program might sometime run completely amok, at which point there is +no choice but to stop. If no previous error has been detected, that's bad +news; a message is printed that is really intended for the \TeX\ +maintenance person instead of the user (unless the user has been +particularly diabolical). The index entries for `this can't happen' may +help to pinpoint the problem. +@^dry rot@> + +@<Error hand...@>= +void confusion(char *@!s) + /*consistency check violated; |s| tells where*/ +{@+normalize_selector(); +if (history < error_message_issued) + {@+print_err("This can't happen (");print(s);print_char(')'); +@.This can't happen@> + help1("I'm broken. Please show this to someone who can fix can fix"); + } +else{@+print_err("I can't go on meeting you like this"); +@.I can't go on...@> + help2("One of your faux pas seems to have wounded me deeply...",@/ + "in fact, I'm barely conscious. Please fix it and try again."); + } +succumb; +} + +@ Users occasionally want to interrupt \TeX\ while it's running. +If the \PASCAL\ runtime system allows this, one can implement +a routine that sets the global variable |interrupt| to some nonzero value +when such an interrupt is signalled. Otherwise there is probably at least +a way to make |interrupt| nonzero using the \PASCAL\ debugger. +@^system dependencies@> +@^debugging@> + +@d check_interrupt {@+if (interrupt!=0) pause_for_instructions(); + } + +@<Global...@>= +static int @!interrupt; /*should \TeX\ pause for instructions?*/ +static bool @!OK_to_interrupt; /*should interrupts be observed?*/ + +@ @<Set init...@>= +interrupt=0;OK_to_interrupt=true; + +@ When an interrupt has been detected, the program goes into its +highest interaction level and lets the user have nearly the full flexibility of +the |error| routine. \TeX\ checks for interrupts only at times when it is +safe to do this. + +@p static void pause_for_instructions(void) +{@+if (OK_to_interrupt) + {@+interaction=error_stop_mode; + if ((selector==log_only)||(selector==no_print)) + incr(selector); + print_err("Interruption"); +@.Interruption@> + help3("You rang?",@/ + "Try to insert some instructions for me (e.g.,`I\\showlists'),",@/ + "unless you just want to quit by typing `X'."); + deletions_allowed=false;error();deletions_allowed=true; + interrupt=0; + } +} + +@* Arithmetic with scaled dimensions. +The principal computations performed by \TeX\ are done entirely in terms of +integers less than $2^{31}$ in magnitude; and divisions are done only when both +dividend and divisor are nonnegative. Thus, the arithmetic specified in this +program can be carried out in exactly the same way on a wide variety of +computers, including some small ones. Why? Because the arithmetic +calculations need to be spelled out precisely in order to guarantee that +\TeX\ will produce identical output on different machines. If some +quantities were rounded differently in different implementations, we would +find that line breaks and even page breaks might occur in different places. +Hence the arithmetic of \TeX\ has been designed with care, and systems that +claim to be implementations of \TeX82 should follow precisely the +@:TeX82}{\TeX82@> +calculations as they appear in the present program. + +(Actually there are three places where \TeX\ uses |/| with a possibly negative +numerator. These are harmless; see |/| in the index. Also if the user +sets the \.{\\time} or the \.{\\year} to a negative value, some diagnostic +information will involve negative-numerator division. The same remarks +apply for |%| as well as for |/|.) + +@ Here is a routine that calculates half of an integer, using an +unambiguous convention with respect to signed odd numbers. + +@p static int half(int @!x) +{@+if (odd(x)) return(x+1)/2; +else return x/2; +} + +@ Fixed-point arithmetic is done on {\sl scaled integers\/} that are multiples +of $2^{-16}$. In other words, a binary point is assumed to be sixteen bit +positions from the right end of a binary computer word. + +@d unity 0200000 /*$2^{16}$, represents 1.00000*/ +@d two 0400000 /*$2^{17}$, represents 2.00000*/ + +@<Types...@>= +typedef int scaled; /*this type is used for scaled integers*/ +typedef int32_t nonnegative_integer; /*$0\le x<2^{31}$*/ +typedef int8_t small_number; /*this type is self-explanatory*/ + +@ The following function is used to create a scaled integer from a given decimal +fraction $(.d_0d_1\ldots d_{k-1})$, where |0 <= k <= 17|. The digit $d_i$ is +given in |dig[i]|, and the calculation produces a correctly rounded result. + +@p static scaled round_decimals(small_number @!k) + /*converts a decimal fraction*/ +{@+int a; /*the accumulator*/ +a=0; +while (k > 0) + {@+decr(k);a=(a+dig[k]*two)/10; + } +return(a+1)/2; +} + +@ Conversely, here is a procedure analogous to |print_int|. If the output +of this procedure is subsequently read by \TeX\ and converted by the +|round_decimals| routine above, it turns out that the original value will +be reproduced exactly; the ``simplest'' such decimal number is output, +but there is always at least one digit following the decimal point. + +The invariant relation in the \&{repeat} loop is that a sequence of +decimal digits yet to be printed will yield the original number if and only if +they form a fraction~$f$ in the range $s-\delta\le 10\cdot2^{16}f<s$. +We can stop if and only if $f=0$ satisfies this condition; the loop will +terminate before $s$ can possibly become zero. + +@p void print_scaled(scaled @!s) /*prints scaled real, rounded to five + digits*/ +{@+scaled delta; /*amount of allowable inaccuracy*/ +if (s < 0) + {@+print_char('-');negate(s); /*print the sign, if negative*/ + } +print_int(s/unity); /*print the integer part*/ +print_char('.'); +s=10*(s%unity)+5;delta=10; +@/do@+{if (delta > unity) s=s+0100000-50000; /*round the last digit*/ +print_char('0'+(s/unity));s=10*(s%unity);delta=delta*10; +}@+ while (!(s <= delta)); +} + +@ Physical sizes that a \TeX\ user specifies for portions of documents are +represented internally as scaled points. Thus, if we define an `sp' (scaled +@^sp@> +point) as a unit equal to $2^{-16}$ printer's points, every dimension +inside of \TeX\ is an integer number of sp. There are exactly +4,736,286.72 sp per inch. Users are not allowed to specify dimensions +larger than $2^{30}-1$ sp, which is a distance of about 18.892 feet (5.7583 +meters); two such quantities can be added without overflow on a 32-bit +computer. + +The present implementation of \TeX\ does not check for overflow when +@^overflow in arithmetic@> +dimensions are added or subtracted. This could be done by inserting a +few dozen tests of the form `\ignorespaces|if (x >= 010000000000)| +\\{report\_overflow}', but the chance of overflow is so remote that +such tests do not seem worthwhile. + +\TeX\ needs to do only a few arithmetic operations on scaled quantities, +other than addition and subtraction, and the following subroutines do most of +the work. A single computation might use several subroutine calls, and it is +desirable to avoid producing multiple error messages in case of arithmetic +overflow; so the routines set the global variable |arith_error| to |true| +instead of reporting errors directly to the user. Another global variable, +|rem|, holds the remainder after a division. + +@<Glob...@>= +static bool @!arith_error; /*has arithmetic overflow occurred recently?*/ +static scaled @!rem; /*amount subtracted to get an exact division*/ + +@ The first arithmetical subroutine we need computes $nx+y$, where |x| +and~|y| are |scaled| and |n| is an integer. We will also use it to +multiply integers. + +@d nx_plus_y(A, B, C) mult_and_add(A, B, C, 07777777777) +@d mult_integers(A, B) mult_and_add(A, B, 0, 017777777777) + +@p static scaled mult_and_add(int @!n, scaled @!x, scaled @!y, scaled @!max_answer) +{@+if (n < 0) + {@+negate(x);negate(n); + } +if (n==0) return y; +else if (((x <= (max_answer-y)/n)&&(-x <= (max_answer+y)/n))) + return n*x+y; +else{@+arith_error=true;return 0; + } +} + +@ We also need to divide scaled dimensions by integers. + +@p static scaled x_over_n(scaled @!x, int @!n) +{@+bool negative; /*should |rem| be negated?*/ +scaled x_over_n; +negative=false; +if (n==0) + {@+arith_error=true;x_over_n=0;rem=x; + } +else{@+if (n < 0) + {@+negate(x);negate(n);negative=true; + } + if (x >= 0) + {@+x_over_n=x/n;rem=x%n; + } + else{@+x_over_n=-((-x)/n);rem=-((-x)%n); + } + } +if (negative) negate(rem); +return x_over_n;} + +@ Then comes the multiplication of a scaled number by a fraction |n/(double)d|, +where |n| and |d| are nonnegative integers | <= @t$2^{16}$@>| and |d| is +positive. It would be too dangerous to multiply by~|n| and then divide +by~|d|, in separate operations, since overflow might well occur; and it +would be too inaccurate to divide by |d| and then multiply by |n|. Hence +this subroutine simulates 1.5-precision arithmetic. + +@p static scaled xn_over_d(scaled @!x, int @!n, int @!d) +{@+bool positive; /*was |x >= 0|?*/ +nonnegative_integer @!t, @!u, @!v; /*intermediate quantities*/ +scaled xn_over_d; +if (x >= 0) positive=true; +else{@+negate(x);positive=false; + } +t=(x%0100000)*n; +u=(x/0100000)*n+(t/0100000); +v=(u%d)*0100000+(t%0100000); +if (u/d >= 0100000) arith_error=true; +else u=0100000*(u/d)+(v/d); +if (positive) + {@+xn_over_d=u;rem=v%d; + } +else{@+xn_over_d=-u;rem=-(v%d); + } +return xn_over_d;} + +@ The next subroutine is used to compute the ``badness'' of glue, when a +total~|t| is supposed to be made from amounts that sum to~|s|. According +to {\sl The \TeX book}, the badness of this situation is $100(t/s)^3$; +however, badness is simply a heuristic, so we need not squeeze out the +last drop of accuracy when computing it. All we really want is an +approximation that has similar properties. +@:TeXbook}{\sl The \TeX book@> + +The actual method used to compute the badness is easier to read from the +program than to describe in words. It produces an integer value that is a +reasonably close approximation to $100(t/s)^3$, and all implementations +of \TeX\ should use precisely this method. Any badness of $2^{13}$ or more is +treated as infinitely bad, and represented by 10000. + +It is not difficult to prove that $$\hbox{|badness(t+1, s) >= badness(t, s) + >= badness(t, s+1)|}.$$ The badness function defined here is capable of +computing at most 1095 distinct values, but that is plenty. + +@d inf_bad 10000 /*infinitely bad value*/ + +@p halfword badness(scaled @!t, scaled @!s) /*compute badness, given |t >= 0|*/ +{@+int r; /*approximation to $\alpha t/s$, where $\alpha^3\approx + 100\cdot2^{18}$*/ +if (t==0) return 0; +else if (s <= 0) return inf_bad; +else{@+if (t <= 7230584) r=(t*297)/s; /*$297^3=99.94\times2^{18}$*/ + else if (s >= 1663497) r=t/(s/297); + else r=t; + if (r > 1290) return inf_bad; /*$1290^3<2^{31}<1291^3$*/ + else return(r*r*r+0400000)/01000000; + } /*that was $r^3/2^{18}$, rounded to the nearest integer*/ +} + +@ When \TeX\ ``packages'' a list into a box, it needs to calculate the +proportionality ratio by which the glue inside the box should stretch +or shrink. This calculation does not affect \TeX's decision making, +so the precise details of rounding, etc., in the glue calculation are not +of critical importance for the consistency of results on different computers. + +We shall use the type |glue_ratio| for such proportionality ratios. +A glue ratio should take the same amount of memory as an +|int| (usually 32 bits) if it is to blend smoothly with \TeX's +other data structures. Thus |glue_ratio| should be equivalent to +|short_real| in some implementations of \PASCAL. Alternatively, +it is possible to deal with glue ratios using nothing but fixed-point +arithmetic; see {\sl TUGboat \bf3},1 (March 1982), 10--27. (But the +routines cited there must be modified to allow negative glue ratios.) +@^system dependencies@> + +@d set_glue_ratio_zero(A) A=0.0 /*store the representation of zero ratio*/ +@d set_glue_ratio_one(A) A=1.0 /*store the representation of unit ratio*/ +@d float(A) ((double)(A)) /*convert from |glue_ratio| to type |double|*/ +@d unfloat(A) ((glue_ratio)(A)) /*convert from |double| to type |glue_ratio|*/ +@d float_constant(A) ((double)(A)) /*convert |int| constant to |double|*/ + +@<Types...@>= +#if __SIZEOF_FLOAT__==4 +typedef float float32_t; +#else +#error float type must have size 4 +#endif +typedef float @!glue_ratio; /*one-word representation of a glue expansion factor*/ + +@* Packed data. +In order to make efficient use of storage space, \TeX\ bases its major data +structures on a |memory_word|, which contains either a (signed) integer, +possibly scaled, or a (signed) |glue_ratio|, or a small number of +fields that are one half or one quarter of the size used for storing +integers. + +If |x| is a variable of type |memory_word|, it contains up to four +fields that can be referred to as follows: +$$\vbox{\halign{\hfil#&#\hfil&#\hfil\cr +|x|&.|i|&(an |int|)\cr +|x|&.|sc|\qquad&(a |scaled| integer)\cr +|x|&.|gr|&(a |glue_ratio|)\cr +|x.hh.lh|, |x.hh|&.|rh|&(two halfword fields)\cr +|x.hh.b0|, |x.hh.b1|, |x.hh|&.|rh|&(two quarterword fields, one halfword + field)\cr +|x.qqqq.b0|, |x.qqqq.b1|, |x.qqqq|&.|b2|, |x.qqqq.b3|\hskip-100pt + &\qquad\qquad\qquad(four quarterword fields)\cr}}$$ +This is somewhat cumbersome to write, and not very readable either, but +macros will be used to make the notation shorter and more transparent. +The \PASCAL\ code below gives a formal definition of |memory_word| and +its subsidiary types, using packed variant records. \TeX\ makes no +assumptions about the relative positions of the fields within a word. + +Since we are assuming 32-bit integers, a halfword must contain at least +16 bits, and a quarterword must contain at least 8 bits. +@^system dependencies@> +But it doesn't hurt to have more bits; for example, with enough 36-bit +words you might be able to have |mem_max| as large as 262142, which is +eight times as much memory as anybody had during the first four years of +\TeX's existence. + +N.B.: Valuable memory space will be dreadfully wasted unless \TeX\ is compiled +by a \PASCAL\ that packs all of the |memory_word| variants into +the space of a single integer. This means, for example, that |glue_ratio| +words should be |short_real| instead of |double| on some computers. Some +\PASCAL\ compilers will pack an integer whose subrange is `|0 dotdot 255|' into +an eight-bit field, but others insist on allocating space for an additional +sign bit; on such systems you can get 256 values into a quarterword only +if the subrange is `|-128 dotdot 127|'. + +The present implementation tries to accommodate as many variations as possible, +so it makes few assumptions. If integers having the subrange +`|min_quarterword dotdot max_quarterword|' can be packed into a quarterword, +and if integers having the subrange `|min_halfword dotdot max_halfword|' +can be packed into a halfword, everything should work satisfactorily. + +It is usually most efficient to have |min_quarterword==min_halfword==0|, +so one should try to achieve this unless it causes a severe problem. +The values defined here are recommended for most 32-bit computers. + +@d min_quarterword 0 /*smallest allowable value in a |quarterword|*/ +@d max_quarterword 65535 /*largest allowable value in a |quarterword|*/ +@d min_halfword 0 /*smallest allowable value in a |halfword|*/ +@d max_halfword 0x3FFFFFFF /*largest allowable value in a |halfword|*/ + +@ Here are the inequalities that the quarterword and halfword values +must satisfy (or rather, the inequalities that they mustn't satisfy): + +@<Check the ``constant''...@>= +#ifdef @!INIT +if ((mem_min!=mem_bot)||(mem_max!=mem_top)) bad=10; +#endif +@;@/ +if ((mem_min > mem_bot)||(mem_max < mem_top)) bad=10; +if ((min_quarterword > 0)||(max_quarterword < 127)) bad=11; +if ((min_halfword > 0)||(max_halfword < 32767)) bad=12; +if ((min_quarterword < min_halfword)||@| + (max_quarterword > max_halfword)) bad=13; +if ((mem_min < min_halfword)||(mem_max >= max_halfword)||@| + (mem_bot-mem_min > max_halfword+1)) bad=14; +if ((font_base < min_quarterword)||(font_max > max_quarterword)) bad=15; +if (font_max > font_base+256) bad=16; +if ((save_size > max_halfword)||(max_strings > max_halfword)) bad=17; +if (buf_size > max_halfword) bad=18; +if (max_quarterword-min_quarterword < 255) bad=19; + +@ The operation of adding or subtracting |min_quarterword| occurs quite +frequently in \TeX, so it is convenient to abbreviate this operation +by using the macros |qi| and |qo| for input and output to and from +quarterword format. + +The inner loop of \TeX\ will run faster with respect to compilers +that don't optimize expressions like `|x+0|' and `|x-0|', if these +macros are simplified in the obvious way when |min_quarterword==0|. +@^inner loop@>@^system dependencies@> + +@d qi(A) A+min_quarterword + /*to put an |eight_bits| item into a quarterword*/ +@d qo(A) A-min_quarterword + /*to take an |eight_bits| item out of a quarterword*/ +@d hi(A) A+min_halfword + /*to put a sixteen-bit item into a halfword*/ +@d ho(A) A-min_halfword + /*to take a sixteen-bit item from a halfword*/ + +@ The reader should study the following definitions closely: +@^system dependencies@> + +@d sc i /*|scaled| data is equivalent to |int|*/ + +@<Types...@>= +typedef uint16_t quarterword; /*1/4 of a word*/ +typedef int32_t halfword; /*1/2 of a word*/ +typedef int8_t two_choices; /*used when there are two variants in a record*/ +typedef int8_t four_choices; /*used when there are four variants in a record*/ +typedef struct { @;@/ + halfword @!rh; + union { + halfword @!lh; + struct { quarterword @!b0;quarterword @!b1;} ; + };} two_halves; +typedef struct { @;@/ + quarterword @!b0; + quarterword @!b1; + quarterword @!b2; + quarterword @!b3; + } four_quarters; +typedef struct { @;@/ + union { + int @!i; + glue_ratio @!gr; + two_halves @!hh; + four_quarters @!qqqq; + };} memory_word; +typedef struct {@+FILE *f;@+memory_word@,d;@+} word_file; + +@ When debugging, we may want to print a |memory_word| without knowing +what type it is; so we print it in all modes. +@^dirty \PASCAL@>@^debugging@> + +@p +#ifdef @!DEBUG +static void print_word(memory_word @!w) + /*prints |w| in all ways*/ +{@+print_int(w.i);print_char(' ');@/ +print_scaled(w.sc);print_char(' ');@/ +print_scaled(round(unity*float(w.gr)));print_ln();@/ +@^real multiplication@> +print_int(w.hh.lh);print_char('=');print_int(w.hh.b0);print_char(':'); +print_int(w.hh.b1);print_char(';');print_int(w.hh.rh);print_char(' ');@/ +print_int(w.qqqq.b0);print_char(':');print_int(w.qqqq.b1);print_char(':'); +print_int(w.qqqq.b2);print_char(':');print_int(w.qqqq.b3); +} +#endif + +@* Dynamic memory allocation. +The \TeX\ system does nearly all of its own memory allocation, so that it +can readily be transported into environments that do not have automatic +facilities for strings, garbage collection, etc., and so that it can be in +control of what error messages the user receives. The dynamic storage +requirements of \TeX\ are handled by providing a large array |mem| in +which consecutive blocks of words are used as nodes by the \TeX\ routines. + +Pointer variables are indices into this array, or into another array +called |eqtb| that will be explained later. A pointer variable might +also be a special flag that lies outside the bounds of |mem|, so we +allow pointers to assume any |halfword| value. The minimum halfword +value represents a null pointer. \TeX\ does not assume that |mem[null]| exists. + +@s pointer int +@d pointer halfword /*a flag or a location in |mem| or |eqtb|*/ +@d null min_halfword /*the null pointer*/ + +@<Glob...@>= +static pointer @!temp_ptr; /*a pointer variable for occasional emergency use*/ + +@ The |mem| array is divided into two regions that are allocated separately, +but the dividing line between these two regions is not fixed; they grow +together until finding their ``natural'' size in a particular job. +Locations less than or equal to |lo_mem_max| are used for storing +variable-length records consisting of two or more words each. This region +is maintained using an algorithm similar to the one described in exercise +2.5--19 of {\sl The Art of Computer Programming}. However, no size field +appears in the allocated nodes; the program is responsible for knowing the +relevant size when a node is freed. Locations greater than or equal to +|hi_mem_min| are used for storing one-word records; a conventional +\.{AVAIL} stack is used for allocation in this region. + +Locations of |mem| between |mem_bot| and |mem_top| may be dumped as part +of preloaded format files, by the \.{INITEX} preprocessor. +@.INITEX@> +Production versions of \TeX\ may extend the memory at both ends in order to +provide more space; locations between |mem_min| and |mem_bot| are always +used for variable-size nodes, and locations between |mem_top| and |mem_max| +are always used for single-word nodes. + +The key pointers that govern |mem| allocation have a prescribed order: +$$\advance\thickmuskip-2mu +\hbox{|null <= mem_min <= mem_bot < lo_mem_max < + hi_mem_min < mem_top <= mem_end <= mem_max|.}$$ + +Empirical tests show that the present implementation of \TeX\ tends to +spend about 9\pct! of its running time allocating nodes, and about 6\pct! +deallocating them after their use. + +@<Glob...@>= +memory_word @!mem0[mem_max-mem_min+1], *const @!mem = @!mem0-mem_min; /*the big dynamic storage area*/ +static pointer @!lo_mem_max; /*the largest location of variable-size memory in use*/ +pointer @!hi_mem_min; /*the smallest location of one-word memory in use*/ + +@ In order to study the memory requirements of particular applications, it +is possible to prepare a version of \TeX\ that keeps track of current and +maximum memory usage. When code between the delimiters | +#ifdef @!STAT +| $\ldots$ +|tats| is not ``commented out,'' \TeX\ will run a bit slower but it will +report these statistics when |tracing_stats| is sufficiently large. + +@<Glob...@>= +int @!var_used, @!dyn_used; /*how much memory is in use*/ +#ifdef @!STAT +#define incr_dyn_used @[incr(dyn_used)@] +#define decr_dyn_used @[decr(dyn_used)@] +#else +#define incr_dyn_used +#define decr_dyn_used +#endif + +@ Let's consider the one-word memory region first, since it's the +simplest. The pointer variable |mem_end| holds the highest-numbered location +of |mem| that has ever been used. The free locations of |mem| that +occur between |hi_mem_min| and |mem_end|, inclusive, are of type +|two_halves|, and we write |info(p)| and |link(p)| for the |lh| +and |rh| fields of |mem[p]| when it is of this type. The single-word +free locations form a linked list +$$|avail|,\;\hbox{|link(avail)|},\;\hbox{|link(link(avail))|},\;\ldots$$ +terminated by |null|. + +@d link(A) mem[A].hh.rh /*the |link| field of a memory word*/ +@d info(A) mem[A].hh.lh /*the |info| field of a memory word*/ + +@<Glob...@>= +static pointer @!avail; /*head of the list of available one-word nodes*/ +static pointer @!mem_end; /*the last one-word node used in |mem|*/ + +@ If memory is exhausted, it might mean that the user has forgotten +a right brace. We will define some procedures later that try to help +pinpoint the trouble. + +@p @<Declare the procedure called |show_token_list|@>@/ +@<Declare the procedure called |runaway|@>@; + +@ The function |get_avail| returns a pointer to a new one-word node whose +|link| field is null. However, \TeX\ will halt if there is no more room left. +@^inner loop@> + +If the available-space list is empty, i.e., if |avail==null|, +we try first to increase |mem_end|. If that cannot be done, i.e., if +|mem_end==mem_max|, we try to decrease |hi_mem_min|. If that cannot be +done, i.e., if |hi_mem_min==lo_mem_max+1|, we have to quit. + +@p static pointer get_avail(void) /*single-word node allocation*/ +{@+pointer p; /*the new node being got*/ +p=avail; /*get top location in the |avail| stack*/ +if (p!=null) avail=link(avail); /*and pop it off*/ +else if (mem_end < mem_max) /*or go into virgin territory*/ + {@+incr(mem_end);p=mem_end; + } +else{@+decr(hi_mem_min);p=hi_mem_min; + if (hi_mem_min <= lo_mem_max) + {@+runaway(); /*if memory is exhausted, display possible runaway text*/ + overflow("main memory size", mem_max+1-mem_min); + /*quit; all one-word nodes are busy*/ +@:TeX capacity exceeded main memory size}{\quad main memory size@> + } + } +link(p)=null; /*provide an oft-desired initialization of the new node*/ +#ifdef @!STAT +incr(dyn_used); +#endif +@; /*maintain statistics*/ +return p; +} + +@ Conversely, a one-word node is recycled by calling |free_avail|. +This routine is part of \TeX's ``inner loop,'' so we want it to be fast. +@^inner loop@> + +@d free_avail(A) /*single-word node liberation*/ + {@+link(A)=avail;avail=A; + decr_dyn_used; + } + +@ There's also a |fast_get_avail| routine, which saves the procedure-call +overhead at the expense of extra programming. This routine is used in +the places that would otherwise account for the most calls of |get_avail|. +@^inner loop@> + +@d fast_get_avail(A) @t@>@;@/ + {@+A=avail; /*avoid |get_avail| if possible, to save time*/ + if (A==null) A=get_avail(); + else{@+avail=link(A);link(A)=null; + incr_dyn_used; + } + } + +@ The procedure |flush_list(p)| frees an entire linked list of +one-word nodes that starts at position |p|. +@^inner loop@> + +@p static void flush_list(pointer @!p) /*makes list of single-word nodes + available*/ +{@+pointer @!q, @!r; /*list traversers*/ +if (p!=null) + {@+r=p; + @/do@+{q=r;r=link(r); +#ifdef @!STAT +decr(dyn_used); +#endif + }@+ while (!(r==null)); /*now |q| is the last node on the list*/ + link(q)=avail;avail=p; + } +} + +@ The available-space list that keeps track of the variable-size portion +of |mem| is a nonempty, doubly-linked circular list of empty nodes, +pointed to by the roving pointer |rover|. + +Each empty node has size 2 or more; the first word contains the special +value |max_halfword| in its |link| field and the size in its |info| field; +the second word contains the two pointers for double linking. + +Each nonempty node also has size 2 or more. Its first word is of type +|two_halves|\kern-1pt, and its |link| field is never equal to |max_halfword|. +Otherwise there is complete flexibility with respect to the contents +of its other fields and its other words. + +(We require |mem_max < max_halfword| because terrible things can happen +when |max_halfword| appears in the |link| field of a nonempty node.) + +@d empty_flag max_halfword /*the |link| of an empty variable-size node*/ +@d is_empty(A) (link(A)==empty_flag) /*tests for empty node*/ +@d node_size(A) info(A) /*the size field in empty variable-size nodes*/ +@d llink(A) info(A+1) /*left link in doubly-linked list of empty nodes*/ +@d rlink(A) link(A+1) /*right link in doubly-linked list of empty nodes*/ + +@<Glob...@>= +static pointer @!rover; /*points to some node in the list of empties*/ + +@ A call to |get_node| with argument |s| returns a pointer to a new node +of size~|s|, which must be 2~or more. The |link| field of the first word +of this new node is set to null. An overflow stop occurs if no suitable +space exists. + +If |get_node| is called with $s=2^{30}$, it simply merges adjacent free +areas and returns the value |max_halfword|. + +@p pointer get_node(int @!s) /*variable-size node allocation*/ +{@+ +pointer p; /*the node currently under inspection*/ +pointer @!q; /*the node physically after node |p|*/ +int @!r; /*the newly allocated node, or a candidate for this honor*/ +int @!t; /*temporary register*/ +restart: p=rover; /*start at some free node in the ring*/ +@/do@+{@<Try to allocate within node |p| and its physical successors, and |goto found| +if allocation was possible@>; +@^inner loop@> +p=rlink(p); /*move to the next node in the ring*/ +}@+ while (!(p==rover)); /*repeat until the whole list has been traversed*/ +if (s==010000000000) + {@+return max_halfword; + } +if (lo_mem_max+2 < hi_mem_min) if (lo_mem_max+2 <= mem_bot+max_halfword) + @<Grow more variable-size memory and |goto restart|@>; +overflow("main memory size", mem_max+1-mem_min); + /*sorry, nothing satisfactory is left*/ +@:TeX capacity exceeded main memory size}{\quad main memory size@> +found: link(r)=null; /*this node is now nonempty*/ +#ifdef @!STAT +var_used=var_used+s; /*maintain usage statistics*/ +#endif +@;@/ +return r; +} + +@ The lower part of |mem| grows by 1000 words at a time, unless +we are very close to going under. When it grows, we simply link +a new node into the available-space list. This method of controlled +growth helps to keep the |mem| usage consecutive when \TeX\ is +implemented on ``virtual memory'' systems. +@^virtual memory@> + +@<Grow more variable-size memory and |goto restart|@>= +{@+if (hi_mem_min-lo_mem_max >= 1998) t=lo_mem_max+1000; +else t=lo_mem_max+1+(hi_mem_min-lo_mem_max)/2; + /*|lo_mem_max+2 <= t < hi_mem_min|*/ +p=llink(rover);q=lo_mem_max;rlink(p)=q;llink(rover)=q;@/ +if (t > mem_bot+max_halfword) t=mem_bot+max_halfword; +rlink(q)=rover;llink(q)=p;link(q)=empty_flag;node_size(q)=t-lo_mem_max;@/ +lo_mem_max=t;link(lo_mem_max)=null;info(lo_mem_max)=null; +rover=q;goto restart; +} + +@ Empirical tests show that the routine in this section performs a +node-merging operation about 0.75 times per allocation, on the average, +after which it finds that |r > p+1| about 95\pct! of the time. + +@<Try to allocate...@>= +q=p+node_size(p); /*find the physical successor*/ +@^inner loop@> +while (is_empty(q)) /*merge node |p| with node |q|*/ + {@+t=rlink(q); + if (q==rover) rover=t; + llink(t)=llink(q);rlink(llink(q))=t;@/ + q=q+node_size(q); + } +r=q-s; +if (r > p+1) @<Allocate from the top of node |p| and |goto found|@>; +if (r==p) if (rlink(p)!=p) + @<Allocate entire node |p| and |goto found|@>; +node_size(p)=q-p /*reset the size in case it grew*/ + +@ @<Allocate from the top...@>= +{@+node_size(p)=r-p; /*store the remaining size*/ +@^inner loop@> +rover=p; /*start searching here next time*/ +goto found; +} + +@ Here we delete node |p| from the ring, and let |rover| rove around. + +@<Allocate entire...@>= +{@+rover=rlink(p);t=llink(p); +llink(rover)=t;rlink(t)=rover; +goto found; +} + +@ Conversely, when some variable-size node |p| of size |s| is no longer needed, +the operation |free_node(p, s)| will make its words available, by inserting +|p| as a new empty node just before where |rover| now points. +@^inner loop@> + +@p void free_node(pointer @!p, halfword @!s) /*variable-size node + liberation*/ +{@+pointer q; /*|llink(rover)|*/ +node_size(p)=s;link(p)=empty_flag; +q=llink(rover);llink(p)=q;rlink(p)=rover; /*set both links*/ +llink(rover)=p;rlink(q)=p; /*insert |p| into the ring*/ +#ifdef @!STAT +var_used=var_used-s; +#endif +@; /*maintain statistics*/ +} + +@ Just before \.{INITEX} writes out the memory, it sorts the doubly linked +available space list. The list is probably very short at such times, so a +simple insertion sort is used. The smallest available location will be +pointed to by |rover|, the next-smallest by |rlink(rover)|, etc. + +@p +#ifdef @!INIT +static void sort_avail(void) /*sorts the available variable-size nodes + by location*/ +{@+pointer p, @!q, @!r; /*indices into |mem|*/ +pointer @!old_rover; /*initial |rover| setting*/ +p=get_node(010000000000); /*merge adjacent free areas*/ +p=rlink(rover);rlink(rover)=max_halfword;old_rover=rover; +while (p!=old_rover) @<Sort \(p)|p| into the list starting at |rover| and advance +|p| to |rlink(p)|@>; +p=rover; +while (rlink(p)!=max_halfword) + {@+llink(rlink(p))=p;p=rlink(p); + } +rlink(p)=rover;llink(rover)=p; +} +#endif + +@ The following |while | loop is guaranteed to +terminate, since the list that starts at +|rover| ends with |max_halfword| during the sorting procedure. + +@<Sort \(p)|p|...@>= +if (p < rover) + {@+q=p;p=rlink(q);rlink(q)=rover;rover=q; + } +else{@+q=rover; + while (rlink(q) < p) q=rlink(q); + r=rlink(p);rlink(p)=rlink(q);rlink(q)=p;p=r; + } + +@* Data structures for boxes and their friends. +From the computer's standpoint, \TeX's chief mission is to create +horizontal and vertical lists. We shall now investigate how the elements +of these lists are represented internally as nodes in the dynamic memory. + +A horizontal or vertical list is linked together by |link| fields in +the first word of each node. Individual nodes represent boxes, glue, +penalties, or special things like discretionary hyphens; because of this +variety, some nodes are longer than others, and we must distinguish different +kinds of nodes. We do this by putting a `|type|' field in the first word, +together with the link and an optional `|subtype|'. + +@d type(A) mem[A].hh.b0 /*identifies what kind of node this is*/ +@d subtype(A) mem[A].hh.b1 /*secondary identification in some cases*/ + +@ A |@!char_node|, which represents a single character, is the most important +kind of node because it accounts for the vast majority of all boxes. +Special precautions are therefore taken to ensure that a |char_node| does +not take up much memory space. Every such node is one word long, and in fact +it is identifiable by this property, since other kinds of nodes have at least +two words, and they appear in |mem| locations less than |hi_mem_min|. +This makes it possible to omit the |type| field in a |char_node|, leaving +us room for two bytes that identify a |font| and a |character| within +that font. + +Note that the format of a |char_node| allows for up to 256 different +fonts and up to 256 characters per font; but most implementations will +probably limit the total number of fonts to fewer than 75 per job, +and most fonts will stick to characters whose codes are +less than 128 (since higher codes +are more difficult to access on most keyboards). + +Extensions of \TeX\ intended for oriental languages will need even more +than $256\times256$ possible characters, when we consider different sizes +@^oriental characters@>@^Chinese characters@>@^Japanese characters@> +and styles of type. It is suggested that Chinese and Japanese fonts be +handled by representing such characters in two consecutive |char_node| +entries: The first of these has |font==font_base|, and its |link| points +to the second; +the second identifies the font and the character dimensions. +The saving feature about oriental characters is that most of them have +the same box dimensions. The |character| field of the first |char_node| +is a ``\\{charext}'' that distinguishes between graphic symbols whose +dimensions are identical for typesetting purposes. (See the \MF\ manual.) +Such an extension of \TeX\ would not be difficult; further details are +left to the reader. + +In order to make sure that the |character| code fits in a quarterword, +\TeX\ adds the quantity |min_quarterword| to the actual code. + +Character nodes appear only in horizontal lists, never in vertical lists. + +@d is_char_node(A) (A >= hi_mem_min) + /*does the argument point to a |char_node|?*/ +@d font(A) type(A) /*the font code in a |char_node|*/ +@d character(A) subtype(A) /*the character code in a |char_node|*/ + +@ An |hlist_node| stands for a box that was made from a horizontal list. +Each |hlist_node| is seven words long, and contains the following fields +(in addition to the mandatory |type| and |link|, which we shall not +mention explicitly when discussing the other node types): The |height| and +|width| and |depth| are scaled integers denoting the dimensions of the +box. There is also a |shift_amount| field, a scaled integer indicating +how much this box should be lowered (if it appears in a horizontal list), +or how much it should be moved to the right (if it appears in a vertical +list). There is a |list_ptr| field, which points to the beginning of the +list from which this box was fabricated; if |list_ptr| is |null|, the box +is empty. Finally, there are three fields that represent the setting of +the glue: |glue_set(p)| is a word of type |glue_ratio| that represents +the proportionality constant for glue setting; |glue_sign(p)| is +|stretching| or |shrinking| or |normal| depending on whether or not the +glue should stretch or shrink or remain rigid; and |glue_order(p)| +specifies the order of infinity to which glue setting applies (|normal|, +|fil|, |fill|, or |filll|). The |subtype| field is not used. + +@d hlist_node 0 /*|type| of hlist nodes*/ +@d box_node_size 9 /*number of words to allocate for a box, set, or pack node*/ +@d width_offset 1 /*position of |width| field in a box node*/ +@d depth_offset 2 /*position of |depth| field in a box node*/ +@d height_offset 3 /*position of |height| field in a box node*/ +@d width(A) mem[A+width_offset].sc /*width of the box, in sp*/ +@d depth(A) mem[A+depth_offset].sc /*depth of the box, in sp*/ +@d height(A) mem[A+height_offset].sc /*height of the box, in sp*/ +@d shift_amount(A) mem[A+4].sc /*repositioning distance, in sp*/ +@d list_offset 5 /*position of |list_ptr| field in a box node*/ +@d list_ptr(A) link(A+list_offset) /*beginning of the list inside the box*/ +@d glue_order(A) subtype(A+list_offset) /*applicable order of infinity*/ +@d glue_sign(A) type(A+list_offset) /*stretching or shrinking*/ +@d normal 0 /*the most common case when several cases are named*/ +@d stretching 1 /*glue setting applies to the stretch components*/ +@d shrinking 2 /*glue setting applies to the shrink components*/ +@d glue_offset 6 /*position of |glue_set| in a box node*/ +@d glue_set(A) mem[A+glue_offset].gr + /*a word of type |glue_ratio| for glue setting*/ + +@ The |new_null_box| function returns a pointer to an |hlist_node| in +which all subfields have the values corresponding to `\.{\\hbox\{\}}'. +The |subtype| field is set to |min_quarterword|, since that's the desired +|span_count| value if this |hlist_node| is changed to an |unset_node|. + +@p pointer new_null_box(void) /*creates a new box node*/ +{@+pointer p; /*the new node*/ +p=get_node(box_node_size);type(p)=hlist_node; +subtype(p)=min_quarterword; +width(p)=0;depth(p)=0;height(p)=0;shift_amount(p)=0;list_ptr(p)=null; +glue_sign(p)=normal;glue_order(p)=normal;set_glue_ratio_zero(glue_set(p)); +return p; +} + +@ A |vlist_node| is like an |hlist_node| in all respects except that it +contains a vertical list. + +@d vlist_node 1 /*|type| of vlist nodes*/ + +@ A |rule_node| stands for a solid black rectangle; it has |width|, +|depth|, and |height| fields just as in an |hlist_node|. However, if +any of these dimensions is $-2^{30}$, the actual value will be determined +by running the rule up to the boundary of the innermost enclosing box. +This is called a ``running dimension.'' The |width| is never running in +an hlist; the |height| and |depth| are never running in a~vlist. + +@d rule_node 2 /*|type| of rule nodes*/ +@d rule_node_size 4 /*number of words to allocate for a rule node*/ +@d null_flag -010000000000 /*$-2^{30}$, signifies a missing item*/ +@d is_running(A) (A==null_flag) /*tests for a running dimension*/ + +@ A new rule node is delivered by the |new_rule| function. It +makes all the dimensions ``running,'' so you have to change the +ones that are not allowed to run. + +@p pointer new_rule(void) +{@+pointer p; /*the new node*/ +p=get_node(rule_node_size);type(p)=rule_node; +subtype(p)=0; /*the |subtype| is not used*/ +width(p)=null_flag;depth(p)=null_flag;height(p)=null_flag; +return p; +} + +@ Insertions are represented by |ins_node| records, where the |subtype| +indicates the corresponding box number. For example, `\.{\\insert 250}' +leads to an |ins_node| whose |subtype| is |250+min_quarterword|. +The |height| field of an |ins_node| is slightly misnamed; it actually holds +the natural height plus depth of the vertical list being inserted. +The |depth| field holds the |split_max_depth| to be used in case this +insertion is split, and the |split_top_ptr| points to the corresponding +|split_top_skip|. The |float_cost| field holds the |floating_penalty| that +will be used if this insertion floats to a subsequent page after a +split insertion of the same class. There is one more field, the +|ins_ptr|, which points to the beginning of the vlist for the insertion. + +@d ins_node 3 /*|type| of insertion nodes*/ +@d ins_node_size 5 /*number of words to allocate for an insertion*/ +@d float_cost(A) mem[A+1].i /*the |floating_penalty| to be used*/ +@d ins_ptr(A) info(A+4) /*the vertical list to be inserted*/ +@d split_top_ptr(A) link(A+4) /*the |split_top_skip| to be used*/ + +@ A |mark_node| has a |mark_ptr| field that points to the reference count +of a token list that contains the user's \.{\\mark} text. +This field occupies a full word instead of a halfword, because +there's nothing to put in the other halfword; it is easier in \PASCAL\ to +use the full word than to risk leaving garbage in the unused half. + +@d mark_node 4 /*|type| of a mark node*/ +@d small_node_size 2 /*number of words to allocate for most node types*/ +@d mark_ptr(A) mem[A+1].i /*head of the token list for a mark*/ + +@ An |adjust_node|, which occurs only in horizontal lists, +specifies material that will be moved out into the surrounding +vertical list; i.e., it is used to implement \TeX's `\.{\\vadjust}' +operation. The |adjust_ptr| field points to the vlist containing this +material. + +@d adjust_node 5 /*|type| of an adjust node*/ +@d adjust_ptr(A) mark_ptr(A) /*vertical list to be moved out of horizontal list*/ + +@ A |ligature_node|, which occurs only in horizontal lists, specifies +a character that was fabricated from the interaction of two or more +actual characters. The second word of the node, which is called the +|lig_char| word, contains |font| and |character| fields just as in a +|char_node|. The characters that generated the ligature have not been +forgotten, since they are needed for diagnostic messages and for +hyphenation; the |lig_ptr| field points to a linked list of character +nodes for all original characters that have been deleted. (This list +might be empty if the characters that generated the ligature were +retained in other nodes.) + +The |subtype| field is 0, plus 2 and/or 1 if the original source of the +ligature included implicit left and/or right boundaries. + +@d ligature_node 6 /*|type| of a ligature node*/ +@d lig_char(A) A+1 /*the word where the ligature is to be found*/ +@d lig_ptr(A) link(lig_char(A)) /*the list of characters*/ + +@ The |new_ligature| function creates a ligature node having given +contents of the |font|, |character|, and |lig_ptr| fields. We also have +a |new_lig_item| function, which returns a two-word node having a given +|character| field. Such nodes are used for temporary processing as ligatures +are being created. + +@p static pointer new_ligature(quarterword @!f, quarterword @!c, pointer @!q) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=ligature_node; +font(lig_char(p))=f;character(lig_char(p))=c;lig_ptr(p)=q; +subtype(p)=0;return p; +} +@# +static pointer new_lig_item(quarterword @!c) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);character(p)=c;lig_ptr(p)=null; +return p; +} + +@ A |disc_node|, which occurs only in horizontal lists, specifies a +``dis\-cretion\-ary'' line break. If such a break occurs at node |p|, the text +that starts at |pre_break(p)| will precede the break, the text that starts at +|post_break(p)| will follow the break, and text that appears in the next +|replace_count(p)| nodes will be ignored. For example, an ordinary +discretionary hyphen, indicated by `\.{\\-}', yields a |disc_node| with +|pre_break| pointing to a |char_node| containing a hyphen, |post_break==null|, +and |replace_count==0|. All three of the discretionary texts must be +lists that consist entirely of character, kern, box, rule, and ligature nodes. + +If |pre_break(p)==null|, the |ex_hyphen_penalty| will be charged for this +break. Otherwise the |hyphen_penalty| will be charged. The texts will +actually be substituted into the list by the line-breaking algorithm if it +decides to make the break, and the discretionary node will disappear at +that time; thus, the output routine sees only discretionaries that were +not chosen. + +@d disc_node 7 /*|type| of a discretionary node*/ +@d replace_count(A) (subtype(A)&0x7F) /*how many subsequent nodes to replace*/ +@d set_replace_count(A,B) (subtype(A)=(B)&0x7F) +@d set_auto_disc(A) (subtype(A)|=0x80) +@d is_auto_disc(A) (subtype(A)&0x80) +@d pre_break(A) llink(A) /*text that precedes a discretionary break*/ +@d post_break(A) rlink(A) /*text that follows a discretionary break*/ + +@p pointer new_disc(void) /*creates an empty |disc_node|*/ +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=disc_node; +set_replace_count(p,0);pre_break(p)=null;post_break(p)=null; +return p; +} + +@ A |whatsit_node| is a wild card reserved for extensions to \TeX. The +|subtype| field in its first word says what `\\{whatsit}' it is, and +implicitly determines the node size (which must be 2 or more) and the +format of the remaining words. When a |whatsit_node| is encountered +in a list, special actions are invoked; knowledgeable people who are +careful not to mess up the rest of \TeX\ are able to make \TeX\ do new +things by adding code at the end of the program. For example, there +might be a `\TeX nicolor' extension to specify different colors of ink, +@^extensions to \TeX@> +and the whatsit node might contain the desired parameters. + +The present implementation of \TeX\ treats the features associated with +`\.{\\write}' and `\.{\\special}' as if they were extensions, in order to +illustrate how such routines might be coded. We shall defer further +discussion of extensions until the end of this program. + +@d whatsit_node 8 /*|type| of special extension nodes*/ + +@ A |math_node|, which occurs only in horizontal lists, appears before and +after mathematical formulas. The |subtype| field is |before| before the +formula and |after| after it. There is a |width| field, which represents +the amount of surrounding space inserted by \.{\\mathsurround}. + +@d math_node 9 /*|type| of a math node*/ +@d before 0 /*|subtype| for math node that introduces a formula*/ +@d after 1 /*|subtype| for math node that winds up a formula*/ + +@p static pointer new_math(scaled @!w, small_number @!s) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=math_node; +subtype(p)=s;width(p)=w;return p; +} + +@ \TeX\ makes use of the fact that |hlist_node|, |vlist_node|, +|rule_node|, |ins_node|, |mark_node|, |adjust_node|, |ligature_node|, +|disc_node|, |whatsit_node|, and |math_node| are at the low end of the +type codes, by permitting a break at glue in a list if and only if the +|type| of the previous node is less than |math_node|. Furthermore, a +node is discarded after a break if its type is |math_node| or~more. + +@d precedes_break(A) (type(A) < math_node) +@d non_discardable(A) (type(A) < math_node) + +@ A |glue_node| represents glue in a list. However, it is really only +a pointer to a separate glue specification, since \TeX\ makes use of the +fact that many essentially identical nodes of glue are usually present. +If |p| points to a |glue_node|, |glue_ptr(p)| points to +another packet of words that specify the stretch and shrink components, etc. + +Glue nodes also serve to represent leaders; the |subtype| is used to +distinguish between ordinary glue (which is called |normal|) and the three +kinds of leaders (which are called |a_leaders|, |c_leaders|, and |x_leaders|). +The |leader_ptr| field points to a rule node or to a box node containing the +leaders; it is set to |null| in ordinary glue nodes. + +Many kinds of glue are computed from \TeX's ``skip'' parameters, and +it is helpful to know which parameter has led to a particular glue node. +Therefore the |subtype| is set to indicate the source of glue, whenever +it originated as a parameter. We will be defining symbolic names for the +parameter numbers later (e.g., |line_skip_code==0|, |baseline_skip_code==1|, +etc.); it suffices for now to say that the |subtype| of parametric glue +will be the same as the parameter number, plus~one. + +In math formulas there are two more possibilities for the |subtype| in a +glue node: |mu_glue| denotes an \.{\\mskip} (where the units are scaled \.{mu} +instead of scaled \.{pt}); and |cond_math_glue| denotes the `\.{\\nonscript}' +feature that cancels the glue node immediately following if it appears +in a subscript. + +@d glue_node 10 /*|type| of node that points to a glue specification*/ +@d cond_math_glue 98 /*special |subtype| to suppress glue in the next node*/ +@d mu_glue 99 /*|subtype| for math glue*/ +@d a_leaders 100 /*|subtype| for aligned leaders*/ +@d c_leaders 101 /*|subtype| for centered leaders*/ +@d x_leaders 102 /*|subtype| for expanded leaders*/ +@d glue_ptr(A) llink(A) /*pointer to a glue specification*/ +@d leader_ptr(A) rlink(A) /*pointer to box or rule node for leaders*/ + +@ A glue specification has a halfword reference count in its first word, +@^reference counts@> +representing |null| plus the number of glue nodes that point to it (less one). +Note that the reference count appears in the same position as +the |link| field in list nodes; this is the field that is initialized +to |null| when a node is allocated, and it is also the field that is flagged +by |empty_flag| in empty nodes. + +Glue specifications also contain three |scaled| fields, for the |width|, +|stretch|, and |shrink| dimensions. Finally, there are two one-byte +fields called |stretch_order| and |shrink_order|; these contain the +orders of infinity (|normal|, |fil|, |fill|, or |filll|) +corresponding to the stretch and shrink values. + +@d glue_spec_size 4 /*number of words to allocate for a glue specification*/ +@d glue_ref_count(A) link(A) /*reference count of a glue specification*/ +@d stretch(A) mem[A+2].sc /*the stretchability of this glob of glue*/ +@d shrink(A) mem[A+3].sc /*the shrinkability of this glob of glue*/ +@d stretch_order(A) type(A) /*order of infinity for stretching*/ +@d shrink_order(A) subtype(A) /*order of infinity for shrinking*/ +@d fil 1 /*first-order infinity*/ +@d fill 2 /*second-order infinity*/ +@d filll 3 /*third-order infinity*/ + +@<Types...@>= +typedef int8_t glue_ord; /*infinity to the 0, 1, 2, or 3 power*/ + +@ Here is a function that returns a pointer to a copy of a glue spec. +The reference count in the copy is |null|, because there is assumed +to be exactly one reference to the new specification. + +@p pointer new_spec(pointer @!p) /*duplicates a glue specification*/ +{@+pointer q; /*the new spec*/ +q=get_node(glue_spec_size);@/ +mem[q]=mem[p];glue_ref_count(q)=null;@/ +width(q)=width(p);stretch(q)=stretch(p);shrink(q)=shrink(p); +return q; +} + +@ And here's a function that creates a glue node for a given parameter +identified by its code number; for example, +|new_param_glue(line_skip_code)| returns a pointer to a glue node for the +current \.{\\lineskip}. + +@p pointer new_param_glue(small_number @!n) +{@+pointer p; /*the new node*/ +pointer @!q; /*the glue specification*/ +p=get_node(small_node_size);type(p)=glue_node;subtype(p)=n+1; +leader_ptr(p)=null;@/ +q=@<Current |mem| equivalent of glue parameter number |n|@>@t@>; +glue_ptr(p)=q;incr(glue_ref_count(q)); +return p; +} + +@ Glue nodes that are more or less anonymous are created by |new_glue|, +whose argument points to a glue specification. + +@p pointer new_glue(pointer @!q) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=glue_node;subtype(p)=normal; +leader_ptr(p)=null;glue_ptr(p)=q;incr(glue_ref_count(q)); +return p; +} + +@ Still another subroutine is needed: This one is sort of a combination +of |new_param_glue| and |new_glue|. It creates a glue node for one of +the current glue parameters, but it makes a fresh copy of the glue +specification, since that specification will probably be subject to change, +while the parameter will stay put. The global variable |temp_ptr| is +set to the address of the new spec. + +@p static pointer new_skip_param(small_number @!n) +{@+pointer p; /*the new node*/ +temp_ptr=new_spec(@<Current |mem| equivalent of glue parameter...@>); +p=new_glue(temp_ptr);glue_ref_count(temp_ptr)=null;subtype(p)=n+1; +return p; +} + +@ A |kern_node| has a |width| field to specify a (normally negative) +amount of spacing. This spacing correction appears in horizontal lists +between letters like A and V when the font designer said that it looks +better to move them closer together or further apart. A kern node can +also appear in a vertical list, when its `|width|' denotes additional +spacing in the vertical direction. The |subtype| is either |normal| (for +kerns inserted from font information or math mode calculations) or |explicit| +(for kerns inserted from \.{\\kern} and \.{\\/} commands) or |acc_kern| +(for kerns inserted from non-math accents) or |mu_glue| (for kerns +inserted from \.{\\mkern} specifications in math formulas). + +@d kern_node 11 /*|type| of a kern node*/ +@d explicit 1 /*|subtype| of kern nodes from \.{\\kern} and \.{\\/}*/ +@d acc_kern 2 /*|subtype| of kern nodes from accents*/ + +@ The |new_kern| function creates a kern node having a given width. + +@p static pointer new_kern(scaled @!w) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=kern_node; +subtype(p)=normal; +width(p)=w; +return p; +} + +@ A |penalty_node| specifies the penalty associated with line or page +breaking, in its |penalty| field. This field is a fullword integer, but +the full range of integer values is not used: Any penalty | >= 10000| is +treated as infinity, and no break will be allowed for such high values. +Similarly, any penalty | <= -10000| is treated as negative infinity, and a +break will be forced. + +@d penalty_node 12 /*|type| of a penalty node*/ +@d inf_penalty inf_bad /*``infinite'' penalty value*/ +@d eject_penalty (-inf_penalty) /*``negatively infinite'' penalty value*/ +@d penalty(A) mem[A+1].i /*the added cost of breaking a list here*/ + +@ Anyone who has been reading the last few sections of the program will +be able to guess what comes next. + +@p pointer new_penalty(int @!m) +{@+pointer p; /*the new node*/ +p=get_node(small_node_size);type(p)=penalty_node; +subtype(p)=0; /*the |subtype| is not used*/ +penalty(p)=m;return p; +} + +@ You might think that we have introduced enough node types by now. Well, +almost, but there is one more: An |unset_node| has nearly the same format +as an |hlist_node| or |vlist_node|; it is used for entries in \.{\\halign} +or \.{\\valign} that are not yet in their final form, since the box +dimensions are their ``natural'' sizes before any glue adjustment has been +made. The |glue_set| word is not present; instead, we have a |glue_stretch| +field, which contains the total stretch of order |glue_order| that is +present in the hlist or vlist being boxed. +Similarly, the |shift_amount| field is replaced by a |glue_shrink| field, +containing the total shrink of order |glue_sign| that is present. +The |subtype| field is called |span_count|; an unset box typically +contains the data for |qo(span_count)+1| columns. +Unset nodes will be changed to box nodes when alignment is completed. + +@d unset_node 13 /*|type| for an unset node*/ +@d unset_set_node 32 /*|type| for an unset |set_node|*/ +@d unset_pack_node 33 /*|type| for an unset |pack_node|*/ +@d glue_stretch(A) mem[A+glue_offset].sc /*total stretch in an unset node*/ +@d glue_shrink(A) shift_amount(A) /*total shrink in an unset node*/ +@d span_count(A) subtype(A) /*indicates the number of spanned columns*/ + +@ In fact, there are still more types coming. When we get to math formula +processing we will see that a |style_node| has |type==14|; and a number +of larger type codes will also be defined, for use in math mode only. + +@ Warning: If any changes are made to these data structure layouts, such as +changing any of the node sizes or even reordering the words of nodes, +the |copy_node_list| procedure and the memory initialization code +below may have to be changed. Such potentially dangerous parts of the +program are listed in the index under `data structure assumptions'. +@!@^data structure assumptions@> +However, other references to the nodes are made symbolically in terms of +the \.{WEB} macro definitions above, so that format changes will leave +\TeX's other algorithms intact. +@^system dependencies@> + +@* Memory layout. +Some areas of |mem| are dedicated to fixed usage, since static allocation is +more efficient than dynamic allocation when we can get away with it. For +example, locations |mem_bot| to |mem_bot+3| are always used to store the +specification for glue that is `\.{0pt plus 0pt minus 0pt}'. The +following macro definitions accomplish the static allocation by giving +symbolic names to the fixed positions. Static variable-size nodes appear +in locations |mem_bot| through |lo_mem_stat_max|, and static single-word nodes +appear in locations |hi_mem_stat_min| through |mem_top|, inclusive. It is +harmless to let |lig_trick| and |garbage| share the same location of |mem|. + +@d zero_glue mem_bot /*specification for \.{0pt plus 0pt minus 0pt}*/ +@d fil_glue zero_glue+glue_spec_size /*\.{0pt plus 1fil minus 0pt}*/ +@d fill_glue fil_glue+glue_spec_size /*\.{0pt plus 1fill minus 0pt}*/ +@d ss_glue fill_glue+glue_spec_size /*\.{0pt plus 1fil minus 1fil}*/ +@d fil_neg_glue ss_glue+glue_spec_size /*\.{0pt plus -1fil minus 0pt}*/ +@d lo_mem_stat_max fil_neg_glue+glue_spec_size-1 /*largest statically + allocated word in the variable-size |mem|*/ +@# +@d page_ins_head mem_top /*list of insertion data for current page*/ +@d contrib_head mem_top-1 /*vlist of items not yet on current page*/ +@d page_head mem_top-2 /*vlist for current page*/ +@d temp_head mem_top-3 /*head of a temporary list of some kind*/ +@d hold_head mem_top-4 /*head of a temporary list of another kind*/ +@d adjust_head mem_top-5 /*head of adjustment list returned by |hpack|*/ +@d active mem_top-7 /*head of active list in |line_break|, needs two words*/ +@d align_head mem_top-8 /*head of preamble list for alignments*/ +@d end_span mem_top-9 /*tail of spanned-width lists*/ +@d omit_template mem_top-10 /*a constant token list*/ +@d null_list mem_top-11 /*permanently empty list*/ +@d lig_trick mem_top-12 /*a ligature masquerading as a |char_node|*/ +@d garbage mem_top-12 /*used for scrap information*/ +@d backup_head mem_top-13 /*head of token list built by |scan_keyword|*/ +@d setpage_head mem_top-14 /*head of page template list build by |new_setpage_node|*/ +@d max_page type(setpage_head) /* maximum page template number */ +@d max_stream subtype(setpage_head) /* maximum stream number */ +@d hi_mem_stat_min mem_top-14 /*smallest statically allocated word in + the one-word |mem|*/ +@d hi_mem_stat_usage 15 /*the number of one-word nodes always present*/ + +@ The following code gets |mem| off to a good start, when \TeX\ is +initializing itself the slow~way. + +@<Local variables for init...@>= +int @!k; /*index into |mem|, |eqtb|, etc.*/ + +@ @<Initialize table entries...@>= +for (k=mem_bot+1; k<=lo_mem_stat_max; k++) mem[k].sc=0; + /*all glue dimensions are zeroed*/ +@^data structure assumptions@> +k=mem_bot;@+while (k <= lo_mem_stat_max) + /*set first words of glue specifications*/ + {@+glue_ref_count(k)=null+1; + stretch_order(k)=normal;shrink_order(k)=normal; + k=k+glue_spec_size; + } +stretch(fil_glue)=unity;stretch_order(fil_glue)=fil;@/ +stretch(fill_glue)=unity;stretch_order(fill_glue)=fill;@/ +stretch(ss_glue)=unity;stretch_order(ss_glue)=fil;@/ +shrink(ss_glue)=unity;shrink_order(ss_glue)=fil;@/ +stretch(fil_neg_glue)=-unity;stretch_order(fil_neg_glue)=fil;@/ +rover=lo_mem_stat_max+1; +link(rover)=empty_flag; /*now initialize the dynamic memory*/ +node_size(rover)=1000; /*which is a 1000-word available node*/ +llink(rover)=rover;rlink(rover)=rover;@/ +lo_mem_max=rover+1000;link(lo_mem_max)=null;info(lo_mem_max)=null;@/ +for (k=hi_mem_stat_min; k<=mem_top; k++) + mem[k]=mem[lo_mem_max]; /*clear list heads*/ +@<Initialize the special list heads and constant nodes@>; +avail=null;mem_end=mem_top; +hi_mem_min=hi_mem_stat_min; /*initialize the one-word memory*/ +var_used=lo_mem_stat_max+1-mem_bot;dyn_used=hi_mem_stat_usage; + /*initialize statistics*/ + +@ If \TeX\ is extended improperly, the |mem| array might get screwed up. +For example, some pointers might be wrong, or some ``dead'' nodes might not +have been freed when the last reference to them disappeared. Procedures +|check_mem| and |search_mem| are available to help diagnose such +problems. These procedures make use of two arrays called |is_free| and +|was_free| that are present only if \TeX's debugging routines have +been included. (You may want to decrease the size of |mem| while you +@^debugging@> +are debugging.) + +@<Glob...@>= +#ifdef @!DEBUG +static bool @!is_free0[mem_max-mem_min+1], *const @!is_free = @!is_free0-mem_min; /*free cells*/ +@t\hskip10pt@>static bool @!was_free0[mem_max-mem_min+1], *const @!was_free = @!was_free0-mem_min; + /*previously free cells*/ +@t\hskip10pt@>static pointer @!was_mem_end, @!was_lo_max, @!was_hi_min; + /*previous |mem_end|, |lo_mem_max|, and |hi_mem_min|*/ +@t\hskip10pt@>static bool @!panicking; /*do we want to check memory constantly?*/ +#endif + +@ @<Set initial...@>= +#ifdef @!DEBUG +was_mem_end=mem_min; /*indicate that everything was previously free*/ +was_lo_max=mem_min;was_hi_min=mem_max; +panicking=false; +#endif + +@ Procedure |check_mem| makes sure that the available space lists of +|mem| are well formed, and it optionally prints out all locations +that are reserved now but were free the last time this procedure was called. + +@p +#ifdef @!DEBUG +static void check_mem(bool @!print_locs) +{@+ /*loop exits*/ +int p, @!q; /*current locations of interest in |mem|*/ +bool @!clobbered; /*is something amiss?*/ +for (p=mem_min; p<=lo_mem_max; p++) is_free[p]=false; /*you can probably + do this faster*/ +for (p=hi_mem_min; p<=mem_end; p++) is_free[p]=false; /*ditto*/ +@<Check single-word |avail| list@>; +@<Check variable-size |avail| list@>; +@<Check flags of unavailable nodes@>; +if (print_locs) @<Print newly busy locations@>; +for (p=mem_min; p<=lo_mem_max; p++) was_free[p]=is_free[p]; +for (p=hi_mem_min; p<=mem_end; p++) was_free[p]=is_free[p]; + /*|was_free=is_free| might be faster*/ +was_mem_end=mem_end;was_lo_max=lo_mem_max;was_hi_min=hi_mem_min; +} +#endif + +@ @<Check single-word...@>= +p=avail;q=null;clobbered=false; +while (p!=null) + {@+if ((p > mem_end)||(p < hi_mem_min)) clobbered=true; + else if (is_free[p]) clobbered=true; + if (clobbered) + {@+print_nl("AVAIL list clobbered at "); +@.AVAIL list clobbered...@> + print_int(q);goto done1; + } + is_free[p]=true;q=p;p=link(q); + } +done1: + +@ @<Check variable-size...@>= +p=rover;q=null;clobbered=false; +@/do@+{if ((p >= lo_mem_max)||(p < mem_min)) clobbered=true; + else if ((rlink(p) >= lo_mem_max)||(rlink(p) < mem_min)) clobbered=true; + else if (!(is_empty(p))||(node_size(p) < 2)||@| + (p+node_size(p) > lo_mem_max)||@|(llink(rlink(p))!=p)) clobbered=true; + if (clobbered) + {@+print_nl("Double-AVAIL list clobbered at "); + print_int(q);goto done2; + } +for (q=p; q<=p+node_size(p)-1; q++) /*mark all locations free*/ + {@+if (is_free[q]) + {@+print_nl("Doubly free location at "); +@.Doubly free location...@> + print_int(q);goto done2; + } + is_free[q]=true; + } +q=p;p=rlink(p); +}@+ while (!(p==rover)); +done2: + +@ @<Check flags...@>= +p=mem_min; +while (p <= lo_mem_max) /*node |p| should not be empty*/ + {@+if (is_empty(p)) + {@+print_nl("Bad flag at ");print_int(p); +@.Bad flag...@> + } + while ((p <= lo_mem_max)&&!is_free[p]) incr(p); + while ((p <= lo_mem_max)&&is_free[p]) incr(p); + } + +@ @<Print newly busy...@>= +{@+print_nl("New busy locs:"); +for (p=mem_min; p<=lo_mem_max; p++) + if (!is_free[p]&&((p > was_lo_max)||was_free[p])) + {@+print_char(' ');print_int(p); + } +for (p=hi_mem_min; p<=mem_end; p++) + if (!is_free[p]&& + ((p < was_hi_min)||(p > was_mem_end)||was_free[p])) + {@+print_char(' ');print_int(p); + } +} + +@ The |search_mem| procedure attempts to answer the question ``Who points +to node~|p|?'' In doing so, it fetches |link| and |info| fields of |mem| +that might not be of type |two_halves|. Strictly speaking, this is +@^dirty \PASCAL@> +undefined in \PASCAL, and it can lead to ``false drops'' (words that seem to +point to |p| purely by coincidence). But for debugging purposes, we want +to rule out the places that do {\sl not\/} point to |p|, so a few false +drops are tolerable. + +@p +#ifdef @!DEBUG +static void search_mem(pointer @!p) /*look for pointers to |p|*/ +{@+int q; /*current position being searched*/ +for (q=mem_min; q<=lo_mem_max; q++) + {@+if (link(q)==p) + {@+print_nl("LINK(");print_int(q);print_char(')'); + } + if (info(q)==p) + {@+print_nl("INFO(");print_int(q);print_char(')'); + } + } +for (q=hi_mem_min; q<=mem_end; q++) + {@+if (link(q)==p) + {@+print_nl("LINK(");print_int(q);print_char(')'); + } + if (info(q)==p) + {@+print_nl("INFO(");print_int(q);print_char(')'); + } + } +@<Search |eqtb| for equivalents equal to |p|@>; +@<Search |save_stack| for equivalents that point to |p|@>; +@<Search |hyph_list| for pointers to |p|@>; +} +#endif + +@* Displaying boxes. +We can reinforce our knowledge of the data structures just introduced +by considering two procedures that display a list in symbolic form. +The first of these, called |short_display|, is used in ``overfull box'' +messages to give the top-level description of a list. The other one, +called |show_node_list|, prints a detailed description of exactly what +is in the data structure. + +The philosophy of |short_display| is to ignore the fine points about exactly +what is inside boxes, except that ligatures and discretionary breaks are +expanded. As a result, |short_display| is a recursive procedure, but the +recursion is never more than one level deep. +@^recursion@> + +A global variable |font_in_short_display| keeps track of the font code that +is assumed to be present when |short_display| begins; deviations from this +font will be printed. + +@<Glob...@>= +int @!font_in_short_display; /*an internal font number*/ + +@ Boxes, rules, inserts, whatsits, marks, and things in general that are +sort of ``complicated'' are indicated only by printing `\.{[]}'. + +@p void short_display(int @!p) /*prints highlights of list |p|*/ +{@+int n; /*for replacement counts*/ +while (p > mem_min) + {@+if (is_char_node(p)) + {@+if (p <= mem_end) + {@+if (font(p)!=font_in_short_display) + {@+if ((font(p) < font_base)||(font(p) > font_max)) + print_char('*'); +@.*\relax@> + else@<Print the font identifier for |font(p)|@>; + print_char(' ');font_in_short_display=font(p); + } + print_ASCII(qo(character(p))); + } + } + else@<Print a short indication of the contents of node |p|@>; + p=link(p); + } +} + +@ @<Print a short indication of the contents of node |p|@>= +switch (type(p)) { +case hlist_node: case vlist_node: case ins_node: case whatsit_node: case mark_node: case adjust_node: + case unset_node: case unset_set_node: case unset_pack_node: print("[]");@+break; +case rule_node: print_char('|');@+break; +case glue_node: if (glue_ptr(p)!=zero_glue) print_char(' ');@+break; +case math_node: print_char('$');@+break; +case ligature_node: short_display(lig_ptr(p));@+break; +case disc_node: {@+short_display(pre_break(p)); + short_display(post_break(p));@/ + n=replace_count(p); + while (n > 0) + {@+if (link(p)!=null) p=link(p); + decr(n); + } + } @+break; +default:do_nothing; +} + +@ The |show_node_list| routine requires some auxiliary subroutines: one to +print a font-and-character combination, one to print a token list without +its reference count, and one to print a rule dimension. + +@p static void print_font_and_char(int @!p) /*prints |char_node| data*/ +{@+if (p > mem_end) print_esc("CLOBBERED."); +else{@+if ((font(p) < font_base)||(font(p) > font_max)) print_char('*'); +@.*\relax@> + else@<Print the font identifier for |font(p)|@>; + print_char(' ');print_ASCII(qo(character(p))); + } +} +@# +static void print_mark(int @!p) /*prints token list data in braces*/ +{@+print_char('{'); +if ((p < hi_mem_min)||(p > mem_end)) print_esc("CLOBBERED."); +else show_token_list(link(p), null, max_print_line-10); +print_char('}'); +} +@# +static void print_rule_dimen(scaled @!d) /*prints dimension in rule node*/ +{@+if (is_running(d)) print_char('*');else print_scaled(d); +@.*\relax@> +} + +@ Then there is a subroutine that prints glue stretch and shrink, possibly +followed by the name of finite units: + +@p static void print_glue(scaled @!d, int @!order, char *@!s) + /*prints a glue component*/ +{@+print_scaled(d); +if ((order < normal)||(order > filll)) print("foul"); +else if (order > normal) + {@+print("fil"); + while (order > fil) + {@+print_char('l');decr(order); + } + } +else if (s!=0) print(s); +} + +@ The next subroutine prints a whole glue specification. + +@p void print_spec(int @!p, char *@!s) + /*prints a glue specification*/ +{@+if ((p < mem_min)||(p >= lo_mem_max)) print_char('*'); +@.*\relax@> +else{@+print_scaled(width(p)); + if (s!=0) print(s); + if (stretch(p)!=0) + {@+print(" plus ");print_glue(stretch(p), stretch_order(p), s); + } + if (shrink(p)!=0) + {@+print(" minus ");print_glue(shrink(p), shrink_order(p), s); + } + } +} + +@ We also need to declare some procedures that appear later in this +documentation. + +@p @<Declare procedures needed for displaying the elements of mlists@>@; +@<Declare the procedure called |print_skip_param|@>@; +static void print_xdimen(pointer p) +{ print_scaled(xdimen_width(p)); + if (xdimen_hfactor(p)!=0) + { print_char('+');print_scaled(xdimen_hfactor(p));print("*hsize");} + if (xdimen_vfactor(p)!=0) + { print_char('+');print_scaled(xdimen_vfactor(p));print("*vsize");} +} +extern void print_baseline_skip(int i); + +@ Since boxes can be inside of boxes, |show_node_list| is inherently recursive, +@^recursion@> +up to a given maximum number of levels. The history of nesting is indicated +by the current string, which will be printed at the beginning of each line; +the length of this string, namely |cur_length|, is the depth of nesting. + +Recursive calls on |show_node_list| therefore use the following pattern: + +@d node_list_display(A) + {@+append_char('.');show_node_list(A);flush_char; + } /*|str_room| need not be checked; see |show_box| below*/ + +@ A global variable called |depth_threshold| is used to record the maximum +depth of nesting for which |show_node_list| will show information. If we +have |depth_threshold==0|, for example, only the top level information will +be given and no sublists will be traversed. Another global variable, called +|breadth_max|, tells the maximum number of items to show at each level; +|breadth_max| had better be positive, or you won't see anything. + +@<Glob...@>= +int @!depth_threshold; /*maximum nesting depth in box displays*/ +int @!breadth_max; /*maximum number of items shown at the same list level*/ + +@ Now we are ready for |show_node_list| itself. This procedure has been +written to be ``extra robust'' in the sense that it should not crash or get +into a loop even if the data structures have been messed up by bugs in +the rest of the program. You can safely call its parent routine +|show_box(p)| for arbitrary values of |p| when you are debugging \TeX. +However, in the presence of bad data, the procedure may +@^dirty \PASCAL@>@^debugging@> +fetch a |memory_word| whose variant is different from the way it was stored; +for example, it might try to read |mem[p].hh| when |mem[p]| +contains a scaled integer, if |p| is a pointer that has been +clobbered or chosen at random. + +@p void show_node_list(int @!p) /*prints a node list symbolically*/ +{@+ +int n; /*the number of items already printed at this level*/ +double @!g; /*a glue ratio, as a floating point number*/ +if (cur_length > depth_threshold) + {@+if (p > null) print(" []"); + /*indicate that there's been some truncation*/ + return; + } +n=0; +while (p > mem_min) + {@+print_ln();print_current_string(); /*display the nesting history*/ + if (p > mem_end) /*pointer out of range*/ + {@+print("Bad link, display aborted.");return; +@.Bad link...@> + } + incr(n);if (n > breadth_max) /*time to stop*/ + {@+print("etc.");return; +@.etc@> + } + display_node(p); + p=link(p); + } + +} + +void display_node(pointer p)@t~@> +{ +if (is_char_node(p)) print_font_and_char(p); +else switch (type(p)) { + case hlist_node: case vlist_node: case unset_node: case unset_set_node: case unset_pack_node: @<Display box |p|@>@;@+break; + case rule_node: @<Display rule |p|@>@;@+break; + case ins_node: @<Display insertion |p|@>@;@+break; + case whatsit_node: @<Display the whatsit node |p|@>@;@+break; + case glue_node: @<Display glue |p|@>@;@+break; + case kern_node: @<Display kern |p|@>@;@+break; + case math_node: @<Display math node |p|@>@;@+break; + case ligature_node: @<Display ligature |p|@>@;@+break; + case penalty_node: @<Display penalty |p|@>@;@+break; + case disc_node: @<Display discretionary |p|@>@;@+break; + case mark_node: @<Display mark |p|@>@;@+break; + case adjust_node: @<Display adjustment |p|@>@;@+break; + @t\4@>@<Cases of |show_node_list| that arise in mlists only@>@; + default:print("Unknown node type!"); + } +} + +@ @<Display box |p|@>= +{@+if (type(p)==hlist_node) print_esc("h"); +else if (type(p)==vlist_node) print_esc("v"); +else print_esc("unset"); +print("box(");print_scaled(height(p));print_char('+'); +print_scaled(depth(p));print(")x");print_scaled(width(p)); +if (type(p)==unset_set_node) print("set"); +else if (type(p)==unset_pack_node) print("pack"); +else if (type(p)==unset_node) + @<Display special fields of the unset node |p|@>@; +else{@+@<Display the value of |glue_set(p)|@>; + if (shift_amount(p)!=0) + {@+print(", shifted ");print_scaled(shift_amount(p)); + } + } +node_list_display(list_ptr(p)); /*recursive call*/ +} + +@ @<Display special fields of the unset node |p|@>= +{@+if (span_count(p)!=min_quarterword) + {@+print(" (");print_int(qo(span_count(p))+1); + print(" columns)"); + } +if (glue_stretch(p)!=0) + {@+print(", stretch ");print_glue(glue_stretch(p), glue_order(p), 0); + } +if (glue_shrink(p)!=0) + {@+print(", shrink ");print_glue(glue_shrink(p), glue_sign(p), 0); + } +} + +@ The code will have to change in this place if |glue_ratio| is +a structured type instead of an ordinary |double|. Note that this routine +should avoid arithmetic errors even if the |glue_set| field holds an +arbitrary random value. The following code assumes that a properly +formed nonzero |double| number has absolute value $2^{20}$ or more when +it is regarded as an integer; this precaution was adequate to prevent +floating point underflow on the author's computer. +@^system dependencies@> +@^dirty \PASCAL@> + +@<Display the value of |glue_set(p)|@>= +g=float(glue_set(p)); +if ((g!=float_constant(0))&&(glue_sign(p)!=normal)) + {@+print(", glue set "); + if (glue_sign(p)==shrinking) print("- "); + if (abs(mem[p+glue_offset].i) < 04000000) print("?.?"); + else if (abs(g) > float_constant(20000)) + {@+if (g > float_constant(0)) print_char('>'); + else print("< -"); + print_glue(20000*unity, glue_order(p), 0); + } + else print_glue(round(unity*g), glue_order(p), 0); +@^real multiplication@> + } + +@ @<Display rule |p|@>= +{@+print_esc("rule(");print_rule_dimen(height(p));print_char('+'); +print_rule_dimen(depth(p));print(")x");print_rule_dimen(width(p)); +} + +@ @<Display insertion |p|@>= +{@+print_esc("insert");print_int(qo(subtype(p))); +print("; split(");print_spec(split_top_ptr(p), 0); +print_char(',');print_scaled(depth(p)); +print("); float cost ");print_int(float_cost(p)); +node_list_display(ins_ptr(p)); /*recursive call*/ +} + +@ @<Display glue |p|@>= +if (subtype(p) >= a_leaders) @<Display leaders |p|@>@; +else{@+print_esc("glue"); + if (subtype(p)!=normal) + {@+print_char('('); + if (subtype(p) < cond_math_glue) + print_skip_param(subtype(p)-1); + else if (subtype(p)==cond_math_glue) print_esc("nonscript"); + else print_esc("mskip"); + print_char(')'); + } + if (subtype(p)!=cond_math_glue) + {@+print_char(' '); + if (subtype(p) < cond_math_glue) print_spec(glue_ptr(p), 0); + else print_spec(glue_ptr(p),"mu"); + } + } + +@ @<Display leaders |p|@>= +{@+print_esc(""); +if (subtype(p)==c_leaders) print_char('c'); +else if (subtype(p)==x_leaders) print_char('x'); +print("leaders ");print_spec(glue_ptr(p), 0); +node_list_display(leader_ptr(p)); /*recursive call*/ +} + +@ An ``explicit'' kern value is indicated implicitly by an explicit space. + +@<Display kern |p|@>= +if (subtype(p)!=mu_glue) + {@+print_esc("kern"); + if (subtype(p)!=normal) print_char(' '); + print_scaled(width(p)); + if (subtype(p)==acc_kern) print(" (for accent)"); +@.for accent@> + } +else{@+print_esc("mkern");print_scaled(width(p));print("mu"); + } + +@ @<Display math node |p|@>= +{@+print_esc("math"); +if (subtype(p)==before) print("on"); +else print("off"); +if (width(p)!=0) + {@+print(", surrounded ");print_scaled(width(p)); + } +} + +@ @<Display ligature |p|@>= +{@+print_font_and_char(lig_char(p));print(" (ligature "); +if (subtype(p) > 1) print_char('|'); +font_in_short_display=font(lig_char(p));short_display(lig_ptr(p)); +if (odd(subtype(p))) print_char('|'); +print_char(')'); +} + +@ @<Display penalty |p|@>= +{@+print_esc("penalty ");print_int(penalty(p)); +} + +@ The |post_break| list of a discretionary node is indicated by a prefixed +`\.{\char'174}' instead of the `\..' before the |pre_break| list. + +@<Display discretionary |p|@>= +{@+print_esc("discretionary"); +if (replace_count(p) > 0) + {@+print(" replacing ");print_int(replace_count(p)); + } +node_list_display(pre_break(p)); /*recursive call*/ +append_char('|');show_node_list(post_break(p));flush_char; /*recursive call*/ +} + +@ @<Display mark |p|@>= +{@+print_esc("mark");print_mark(mark_ptr(p)); +} + +@ @<Display adjustment |p|@>= +{@+print_esc("vadjust");node_list_display(adjust_ptr(p)); /*recursive call*/ +} + +@ The recursive machinery is started by calling |show_box|. +@^recursion@> + +@p void show_box(pointer @!p) +{@+@<Assign the values |depth_threshold:=show_box_depth| and |breadth_max:=show_box_breadth|@>; +if (breadth_max <= 0) breadth_max=5; +if (pool_ptr+depth_threshold >= pool_size) + depth_threshold=pool_size-pool_ptr-1; + /*now there's enough room for prefix string*/ +show_node_list(p); /*the show starts at |p|*/ +print_ln(); +} + +@* Destroying boxes. +When we are done with a node list, we are obliged to return it to free +storage, including all of its sublists. The recursive procedure +|flush_node_list| does this for us. + +@ First, however, we shall consider two non-recursive procedures that do +simpler tasks. The first of these, |delete_token_ref|, is called when +a pointer to a token list's reference count is being removed. This means +that the token list should disappear if the reference count was |null|, +otherwise the count should be decreased by one. +@^reference counts@> + +@d token_ref_count(A) info(A) /*reference count preceding a token list*/ + +@p void delete_token_ref(pointer @!p) /*|p| points to the reference count + of a token list that is losing one reference*/ +{@+if (token_ref_count(p)==null) flush_list(p); +else decr(token_ref_count(p)); +} + +@ Similarly, |delete_glue_ref| is called when a pointer to a glue +specification is being withdrawn. +@^reference counts@> +@d fast_delete_glue_ref(A) @t@>@;@/ + {@+if (glue_ref_count(A)==null) free_node(A, glue_spec_size); + else decr(glue_ref_count(A)); + } + +@p void delete_glue_ref(pointer @!p) /*|p| points to a glue specification*/ +fast_delete_glue_ref(p) +void delete_xdimen_ref(pointer @!p) /*|p| points to a xdimen specification*/ +{@+if (xdimen_ref_count(p)==null) free_node(p, xdimen_node_size); + else decr(xdimen_ref_count(p)); +} + +@ Now we are ready to delete any node list, recursively. +In practice, the nodes deleted are usually charnodes (about 2/3 of the time), +and they are glue nodes in about half of the remaining cases. +@^recursion@> + +@p void flush_node_list(pointer @!p) /*erase list of nodes starting at |p|*/ +{@+ /*go here when node |p| has been freed*/ +pointer q; /*successor to node |p|*/ +while (p!=null) +@^inner loop@> + {@+q=link(p); + if (is_char_node(p)) free_avail(p)@; + else{@+switch (type(p)) { + case hlist_node: case vlist_node: case unset_node: case unset_set_node: case unset_pack_node: {@+flush_node_list(list_ptr(p)); + free_node(p, box_node_size);goto done; + } + case rule_node: {@+free_node(p, rule_node_size);goto done; + } + case ins_node: {@+flush_node_list(ins_ptr(p)); + delete_glue_ref(split_top_ptr(p)); + free_node(p, ins_node_size);goto done; + } + case whatsit_node: @<Wipe out the whatsit node |p| and |goto done|@>@; + case glue_node: {@+fast_delete_glue_ref(glue_ptr(p)); + if (leader_ptr(p)!=null) flush_node_list(leader_ptr(p)); + } @+break; + case kern_node: case math_node: case penalty_node: do_nothing;@+break; + case ligature_node: flush_node_list(lig_ptr(p));@+break; + case mark_node: delete_token_ref(mark_ptr(p));@+break; + case disc_node: {@+flush_node_list(pre_break(p)); + flush_node_list(post_break(p)); + } @+break; + case adjust_node: flush_node_list(adjust_ptr(p));@+break; + @t\4@>@<Cases of |flush_node_list| that arise in mlists only@>@; + default:confusion("flushing"); +@:this can't happen flushing}{\quad flushing@> + } @/ + free_node(p, small_node_size); + done: ;} + p=q; + } +} + +@* Copying boxes. +Another recursive operation that acts on boxes is sometimes needed: The +procedure |copy_node_list| returns a pointer to another node list that has +the same structure and meaning as the original. Note that since glue +specifications and token lists have reference counts, we need not make +copies of them. Reference counts can never get too large to fit in a +halfword, since each pointer to a node is in a different memory address, +and the total number of memory addresses fits in a halfword. +@^recursion@> +@^reference counts@> + +(Well, there actually are also references from outside |mem|; if the +|save_stack| is made arbitrarily large, it would theoretically be possible +to break \TeX\ by overflowing a reference count. But who would want to do that?) + +@d add_token_ref(A) incr(token_ref_count(A)) /*new reference to a token list*/ +@d add_glue_ref(A) incr(glue_ref_count(A)) /*new reference to a glue spec*/ +@d add_xdimen_ref(A) incr(xdimen_ref_count(A)) /*new reference to an xdimen*/ + +@ The copying procedure copies words en masse without bothering +to look at their individual fields. If the node format changes---for +example, if the size is altered, or if some link field is moved to another +relative position---then this code may need to be changed too. +@^data structure assumptions@> + +@p pointer copy_node_list(pointer @!p) /*makes a duplicate of the + node list that starts at |p| and returns a pointer to the new list*/ +{@+pointer h; /*temporary head of copied list*/ +pointer @!q; /*previous position in new list*/ +pointer @!r; /*current node being fabricated for new list*/ +int @!words; /*number of words remaining to be copied*/ +h=get_avail();q=h; +while (p!=null) + {@+@<Make a copy of node |p| in node |r|@>; + link(q)=r;q=r;p=link(p); + } +link(q)=null;q=link(h);free_avail(h); +return q; +} + +@ @<Make a copy of node |p|...@>= +words=1; /*this setting occurs in more branches than any other*/ +if (is_char_node(p)) r=get_avail(); +else@<Case statement to copy different types and set |words| to the number of initial +words not yet copied@>; +while (words > 0) + {@+decr(words);mem[r+words]=mem[p+words]; + } + +@ @<Case statement to copy...@>= +switch (type(p)) { +case hlist_node: case vlist_node: case unset_node: case unset_set_node: case unset_pack_node: {@+r=get_node(box_node_size); + mem[r+6]=mem[p+6];mem[r+5]=mem[p+5]; /*copy the last two words*/ + list_ptr(r)=copy_node_list(list_ptr(p)); /*this affects |mem[r+5]|*/ + words=5; + } @+break; +case rule_node: {@+r=get_node(rule_node_size);words=rule_node_size; + } @+break; +case ins_node: {@+r=get_node(ins_node_size);mem[r+4]=mem[p+4]; + add_glue_ref(split_top_ptr(p)); + ins_ptr(r)=copy_node_list(ins_ptr(p)); /*this affects |mem[r+4]|*/ + words=ins_node_size-1; + } @+break; +case whatsit_node: @<Make a partial copy of the whatsit node |p| and make |r| point +to it; set |words| to the number of initial words not yet copied@>@;@+break; +case glue_node: {@+r=get_node(small_node_size);add_glue_ref(glue_ptr(p)); + glue_ptr(r)=glue_ptr(p);leader_ptr(r)=copy_node_list(leader_ptr(p)); + } @+break; +case kern_node: case math_node: case penalty_node: {@+r=get_node(small_node_size); + words=small_node_size; + } @+break; +case ligature_node: {@+r=get_node(small_node_size); + mem[lig_char(r)]=mem[lig_char(p)]; /*copy |font| and |character|*/ + lig_ptr(r)=copy_node_list(lig_ptr(p)); + } @+break; +case disc_node: {@+r=get_node(small_node_size); + pre_break(r)=copy_node_list(pre_break(p)); + post_break(r)=copy_node_list(post_break(p)); + } @+break; +case mark_node: {@+r=get_node(small_node_size);add_token_ref(mark_ptr(p)); + words=small_node_size; + } @+break; +case adjust_node: {@+r=get_node(small_node_size); + adjust_ptr(r)=copy_node_list(adjust_ptr(p)); + } @+break; /*|words==1==small_node_size-1|*/ +default:confusion("copying"); +@:this can't happen copying}{\quad copying@> +} + +@* The command codes. +Before we can go any further, we need to define symbolic names for the internal +code numbers that represent the various commands obeyed by \TeX. These codes +are somewhat arbitrary, but not completely so. For example, the command +codes for character types are fixed by the language, since a user says, +e.g., `\.{\\catcode \`\\\${} = 3}' to make \.{\char'44} a math delimiter, +and the command code |math_shift| is equal to~3. Some other codes have +been made adjacent so that |case| statements in the program need not consider +cases that are widely spaced, or so that |case| statements can be replaced +by |if (| statements. + +At any rate, here is the list, for future reference. First come the +``catcode'' commands, several of which share their numeric codes with +ordinary commands when the catcode cannot emerge from \TeX's scanning routine. + +@d escape 0 /*escape delimiter (called \.\\ in {\sl The \TeX book\/})*/ +@:TeXbook}{\sl The \TeX book@> +@d relax 0 /*do nothing ( \.{\\relax} )*/ +@d left_brace 1 /*beginning of a group ( \.\{ )*/ +@d right_brace 2 /*ending of a group ( \.\} )*/ +@d math_shift 3 /*mathematics shift character ( \.\$ )*/ +@d tab_mark 4 /*alignment delimiter ( \.\&, \.{\\span} )*/ +@d car_ret 5 /*end of line ( |carriage_return|, \.{\\cr}, \.{\\crcr} )*/ +@d out_param 5 /*output a macro parameter*/ +@d mac_param 6 /*macro parameter symbol ( \.\# )*/ +@d sup_mark 7 /*superscript ( \.{\char'136} )*/ +@d sub_mark 8 /*subscript ( \.{\char'137} )*/ +@d ignore 9 /*characters to ignore ( \.{\^\^@@} )*/ +@d endv 9 /*end of \<v_j> list in alignment template*/ +@d spacer 10 /*characters equivalent to blank space ( \.{\ } )*/ +@d letter 11 /*characters regarded as letters ( \.{A..Z}, \.{a..z} )*/ +@d other_char 12 /*none of the special character types*/ +@d active_char 13 /*characters that invoke macros ( \.{\char`\~} )*/ +@d par_end 13 /*end of paragraph ( \.{\\par} )*/ +@d match 13 /*match a macro parameter*/ +@d comment 14 /*characters that introduce comments ( \.\% )*/ +@d end_match 14 /*end of parameters to macro*/ +@d stop 14 /*end of job ( \.{\\end}, \.{\\dump} )*/ +@d invalid_char 15 /*characters that shouldn't appear ( \.{\^\^?} )*/ +@d delim_num 15 /*specify delimiter numerically ( \.{\\delimiter} )*/ +@d max_char_code 15 /*largest catcode for individual characters*/ + +@ Next are the ordinary run-of-the-mill command codes. Codes that are +|min_internal| or more represent internal quantities that might be +expanded by `\.{\\the}'. + +@d char_num 16 /*character specified numerically ( \.{\\char} )*/ +@d math_char_num 17 /*explicit math code ( \.{\\mathchar} )*/ +@d mark 18 /*mark definition ( \.{\\mark} )*/ +@d xray 19 /*peek inside of \TeX\ ( \.{\\show}, \.{\\showbox}, etc.~)*/ +@d make_box 20 /*make a box ( \.{\\box}, \.{\\copy}, \.{\\hbox}, etc.~)*/ +@d hmove 21 /*horizontal motion ( \.{\\moveleft}, \.{\\moveright} )*/ +@d vmove 22 /*vertical motion ( \.{\\raise}, \.{\\lower} )*/ +@d un_hbox 23 /*unglue a box ( \.{\\unhbox}, \.{\\unhcopy} )*/ +@d un_vbox 24 /*unglue a box ( \.{\\unvbox}, \.{\\unvcopy} )*/ +@d remove_item 25 /*nullify last item ( \.{\\unpenalty}, + \.{\\unkern}, \.{\\unskip} )*/ +@d hskip 26 /*horizontal glue ( \.{\\hskip}, \.{\\hfil}, etc.~)*/ +@d vskip 27 /*vertical glue ( \.{\\vskip}, \.{\\vfil}, etc.~)*/ +@d mskip 28 /*math glue ( \.{\\mskip} )*/ +@d kern 29 /*fixed space ( \.{\\kern})*/ +@d mkern 30 /*math kern ( \.{\\mkern} )*/ +@d leader_ship 31 /*use a box ( \.{\\shipout}, \.{\\leaders}, etc.~)*/ +@d halign 32 /*horizontal table alignment ( \.{\\halign} )*/ +@d valign 33 /*vertical table alignment ( \.{\\valign} )*/ +@d no_align 34 /*temporary escape from alignment ( \.{\\noalign} )*/ +@d vrule 35 /*vertical rule ( \.{\\vrule} )*/ +@d hrule 36 /*horizontal rule ( \.{\\hrule} )*/ +@d insert 37 /*vlist inserted in box ( \.{\\insert} )*/ +@d vadjust 38 /*vlist inserted in enclosing paragraph ( \.{\\vadjust} )*/ +@d ignore_spaces 39 /*gobble |spacer| tokens ( \.{\\ignorespaces} )*/ +@d after_assignment 40 /*save till assignment is done ( \.{\\afterassignment} )*/ +@d after_group 41 /*save till group is done ( \.{\\aftergroup} )*/ +@d break_penalty 42 /*additional badness ( \.{\\penalty} )*/ +@d start_par 43 /*begin paragraph ( \.{\\indent}, \.{\\noindent} )*/ +@d ital_corr 44 /*italic correction ( \.{\\/} )*/ +@d accent 45 /*attach accent in text ( \.{\\accent} )*/ +@d math_accent 46 /*attach accent in math ( \.{\\mathaccent} )*/ +@d discretionary 47 /*discretionary texts ( \.{\\-}, \.{\\discretionary} )*/ +@d eq_no 48 /*equation number ( \.{\\eqno}, \.{\\leqno} )*/ +@d left_right 49 /*variable delimiter ( \.{\\left}, \.{\\right} )*/ + /*( or \.{\\middle} )*/ +@d math_comp 50 /*component of formula ( \.{\\mathbin}, etc.~)*/ +@d limit_switch 51 /*diddle limit conventions ( \.{\\displaylimits}, etc.~)*/ +@d above 52 /*generalized fraction ( \.{\\above}, \.{\\atop}, etc.~)*/ +@d math_style 53 /*style specification ( \.{\\displaystyle}, etc.~)*/ +@d math_choice 54 /*choice specification ( \.{\\mathchoice} )*/ +@d non_script 55 /*conditional math glue ( \.{\\nonscript} )*/ +@d vcenter 56 /*vertically center a vbox ( \.{\\vcenter} )*/ +@d case_shift 57 /*force specific case ( \.{\\lowercase}, \.{\\uppercase}~)*/ +@d message 58 /*send to user ( \.{\\message}, \.{\\errmessage} )*/ +@d extension 59 /*extensions to \TeX\ ( \.{\\write}, \.{\\special}, etc.~)*/ +@d in_stream 60 /*files for reading ( \.{\\openin}, \.{\\closein} )*/ +@d begin_group 61 /*begin local grouping ( \.{\\begingroup} )*/ +@d end_group 62 /*end local grouping ( \.{\\endgroup} )*/ +@d omit 63 /*omit alignment template ( \.{\\omit} )*/ +@d ex_space 64 /*explicit space ( \.{\\\ } )*/ +@d no_boundary 65 /*suppress boundary ligatures ( \.{\\noboundary} )*/ +@d radical 66 /*square root and similar signs ( \.{\\radical} )*/ +@d end_cs_name 67 /*end control sequence ( \.{\\endcsname} )*/ +@d min_internal 68 /*the smallest code that can follow \.{\\the}*/ +@d char_given 68 /*character code defined by \.{\\chardef}*/ +@d math_given 69 /*math code defined by \.{\\mathchardef}*/ +@d last_item 70 /*most recent item ( \.{\\lastpenalty}, + \.{\\lastkern}, \.{\\lastskip} )*/ +@d max_non_prefixed_command 70 /*largest command code that can't be \.{\\global}*/ + +@ The next codes are special; they all relate to mode-independent +assignment of values to \TeX's internal registers or tables. +Codes that are |max_internal| or less represent internal quantities +that might be expanded by `\.{\\the}'. + +@d toks_register 71 /*token list register ( \.{\\toks} )*/ +@d assign_toks 72 /*special token list ( \.{\\output}, \.{\\everypar}, etc.~)*/ +@d assign_int 73 /*user-defined integer ( \.{\\tolerance}, \.{\\day}, etc.~)*/ +@d assign_dimen 74 /*user-defined length ( \.{\\hsize}, etc.~)*/ +@d assign_glue 75 /*user-defined glue ( \.{\\baselineskip}, etc.~)*/ +@d assign_mu_glue 76 /*user-defined muglue ( \.{\\thinmuskip}, etc.~)*/ +@d assign_font_dimen 77 /*user-defined font dimension ( \.{\\fontdimen} )*/ +@d assign_font_int 78 /*user-defined font integer ( \.{\\hyphenchar}, + \.{\\skewchar} )*/ +@d set_aux 79 /*specify state info ( \.{\\spacefactor}, \.{\\prevdepth} )*/ +@d set_prev_graf 80 /*specify state info ( \.{\\prevgraf} )*/ +@d set_page_dimen 81 /*specify state info ( \.{\\pagegoal}, etc.~)*/ +@d set_page_int 82 /*specify state info ( \.{\\deadcycles}, + \.{\\insertpenalties} )*/ + /*( or \.{\\interactionmode} )*/ +@d set_box_dimen 83 /*change dimension of box ( \.{\\wd}, \.{\\ht}, \.{\\dp} )*/ +@d set_shape 84 /*specify fancy paragraph shape ( \.{\\parshape} )*/ + /*(or \.{\\interlinepenalties}, etc.~)*/ +@d def_code 85 /*define a character code ( \.{\\catcode}, etc.~)*/ +@d def_family 86 /*declare math fonts ( \.{\\textfont}, etc.~)*/ +@d set_font 87 /*set current font ( font identifiers )*/ +@d def_font 88 /*define a font file ( \.{\\font} )*/ +@d internal_register 89 /*internal register ( \.{\\count}, \.{\\dimen}, etc.~)*/ +@d max_internal 89 /*the largest code that can follow \.{\\the}*/ +@d advance 90 /*advance a register or parameter ( \.{\\advance} )*/ +@d multiply 91 /*multiply a register or parameter ( \.{\\multiply} )*/ +@d divide 92 /*divide a register or parameter ( \.{\\divide} )*/ +@d prefix 93 /*qualify a definition ( \.{\\global}, \.{\\long}, \.{\\outer} )*/ + /*( or \.{\\protected} )*/ +@d let 94 /*assign a command code ( \.{\\let}, \.{\\futurelet} )*/ +@d shorthand_def 95 /*code definition ( \.{\\chardef}, \.{\\countdef}, etc.~)*/ +@d read_to_cs 96 /*read into a control sequence ( \.{\\read} )*/ + /*( or \.{\\readline} )*/ +@d def 97 /*macro definition ( \.{\\def}, \.{\\gdef}, \.{\\xdef}, \.{\\edef} )*/ +@d set_box 98 /*set a box ( \.{\\setbox} )*/ +@d hyph_data 99 /*hyphenation data ( \.{\\hyphenation}, \.{\\patterns} )*/ +@d set_interaction 100 /*define level of interaction ( \.{\\batchmode}, etc.~)*/ +@d max_command 100 /*the largest command code seen at |big_switch|*/ + +@ The remaining command codes are extra special, since they cannot get through +\TeX's scanner to the main control routine. They have been given values higher +than |max_command| so that their special nature is easily discernible. +The ``expandable'' commands come first. + +@d undefined_cs (max_command+1) /*initial state of most |eq_type| fields*/ +@d expand_after (max_command+2) /*special expansion ( \.{\\expandafter} )*/ +@d no_expand (max_command+3) /*special nonexpansion ( \.{\\noexpand} )*/ +@d input (max_command+4) /*input a source file ( \.{\\input}, \.{\\endinput} )*/ + /*( or \.{\\scantokens} )*/ +@d if_test (max_command+5) /*conditional text ( \.{\\if}, \.{\\ifcase}, etc.~)*/ +@d fi_or_else (max_command+6) /*delimiters for conditionals ( \.{\\else}, etc.~)*/ +@d cs_name (max_command+7) /*make a control sequence from tokens ( \.{\\csname} )*/ +@d convert (max_command+8) /*convert to text ( \.{\\number}, \.{\\string}, etc.~)*/ +@d the (max_command+9) /*expand an internal quantity ( \.{\\the} )*/ + /*( or \.{\\unexpanded}, \.{\\detokenize} )*/ +@d top_bot_mark (max_command+10) /*inserted mark ( \.{\\topmark}, etc.~)*/ +@d call (max_command+11) /*non-long, non-outer control sequence*/ +@d long_call (max_command+12) /*long, non-outer control sequence*/ +@d outer_call (max_command+13) /*non-long, outer control sequence*/ +@d long_outer_call (max_command+14) /*long, outer control sequence*/ +@d end_template (max_command+15) /*end of an alignment template*/ +@d dont_expand (max_command+16) /*the following token was marked by \.{\\noexpand}*/ +@d glue_ref (max_command+17) /*the equivalent points to a glue specification*/ +@d shape_ref (max_command+18) /*the equivalent points to a parshape specification*/ +@d box_ref (max_command+19) /*the equivalent points to a box node, or is |null|*/ +@d data (max_command+20) /*the equivalent is simply a halfword number*/ + +@* The semantic nest. +\TeX\ is typically in the midst of building many lists at once. For example, +when a math formula is being processed, \TeX\ is in math mode and +working on an mlist; this formula has temporarily interrupted \TeX\ from +being in horizontal mode and building the hlist of a paragraph; and this +paragraph has temporarily interrupted \TeX\ from being in vertical mode +and building the vlist for the next page of a document. Similarly, when a +\.{\\vbox} occurs inside of an \.{\\hbox}, \TeX\ is temporarily +interrupted from working in restricted horizontal mode, and it enters +internal vertical mode. The ``semantic nest'' is a stack that +keeps track of what lists and modes are currently suspended. + +At each level of processing we are in one of six modes: + +\yskip\hang|vmode| stands for vertical mode (the page builder); + +\hang|hmode| stands for horizontal mode (the paragraph builder); + +\hang|mmode| stands for displayed formula mode; + +\hang|-vmode| stands for internal vertical mode (e.g., in a \.{\\vbox}); + +\hang|-hmode| stands for restricted horizontal mode (e.g., in an \.{\\hbox}); + +\hang|-mmode| stands for math formula mode (not displayed). + +\yskip\noindent The mode is temporarily set to zero while processing \.{\\write} +texts in the |ship_out| routine. + +Numeric values are assigned to |vmode|, |hmode|, and |mmode| so that +\TeX's ``big semantic switch'' can select the appropriate thing to +do by computing the value |abs(mode)+cur_cmd|, where |mode| is the current +mode and |cur_cmd| is the current command code. + +@d vmode 1 /*vertical mode*/ +@d hmode (vmode+max_command+1) /*horizontal mode*/ +@d mmode (hmode+max_command+1) /*math mode*/ + +@p static void print_mode(int @!m) /*prints the mode represented by |m|*/ +{@+if (m > 0) + switch (m/(max_command+1)) { + case 0: print("vertical");@+break; + case 1: print("horizontal");@+break; + case 2: print("display math"); + } +else if (m==0) print("no"); +else switch ((-m)/(max_command+1)) { + case 0: print("internal vertical");@+break; + case 1: print("restricted horizontal");@+break; + case 2: print("math"); + } +print(" mode"); +} + +@ The state of affairs at any semantic level can be represented by +five values: + +\yskip\hang|mode| is the number representing the semantic mode, as +just explained. + +\yskip\hang|head| is a |pointer| to a list head for the list being built; +|link(head)| therefore points to the first element of the list, or +to |null| if the list is empty. + +\yskip\hang|tail| is a |pointer| to the final node of the list being +built; thus, |tail==head| if and only if the list is empty. + +\yskip\hang|prev_graf| is the number of lines of the current paragraph that +have already been put into the present vertical list. + +\yskip\hang|aux| is an auxiliary |memory_word| that gives further information +that is needed to characterize the situation. + +\yskip\noindent +In vertical mode, |aux| is also known as |prev_depth|; it is the scaled +value representing the depth of the previous box, for use in baseline +calculations, or it is | <= -1000|pt if the next box on the vertical list is to +be exempt from baseline calculations. In horizontal mode, |aux| is also +known as |space_factor| and |clang|; it holds the current space factor used in +spacing calculations, and the current language used for hyphenation. +(The value of |clang| is undefined in restricted horizontal mode.) +In math mode, |aux| is also known as |incompleat_noad|; if +not |null|, it points to a record that represents the numerator of a +generalized fraction for which the denominator is currently being formed +in the current list. + +There is also a sixth quantity, |mode_line|, which correlates +the semantic nest with the user's input; |mode_line| contains the source +line number at which the current level of nesting was entered. The negative +of this line number is the |mode_line| at the level of the +user's output routine. + +A seventh quantity, |eTeX_aux|, is used by the extended features \eTeX. +In vertical modes it is known as |LR_save| and holds the LR stack when a +paragraph is interrupted by a displayed formula. In display math mode +it is known as |LR_box| and holds a pointer to a prototype box for the +display. In math mode it is known as |delim_ptr| and points to the most +recent |left_noad| or |middle_noad| of a |math_left_group|. + +In horizontal mode, the |prev_graf| field is used for initial language data. + +The semantic nest is an array called |nest| that holds the |mode|, |head|, +|tail|, |prev_graf|, |aux|, and |mode_line| values for all semantic levels +below the currently active one. Information about the currently active +level is kept in the global quantities |mode|, |head|, |tail|, |prev_graf|, +|aux|, and |mode_line|, which live in a \PASCAL\ record that is ready to +be pushed onto |nest| if necessary. + +@d ignore_depth (-1000*unity) /*|prev_depth| value that is ignored*/ +@d unknown_depth (-2000*unity) /*|prev_depth| value that is unknown*/ + +@<Types...@>= +typedef struct { int16_t @!mode_field;@+ + pointer @!head_field, @!tail_field; + pointer @!eTeX_aux_field; + int @!pg_field, @!ml_field;@+ + memory_word @!aux_field; + } list_state_record; + +@ @d mode cur_list.mode_field /*current mode*/ +@d head cur_list.head_field /*header node of current list*/ +@d tail cur_list.tail_field /*final node on current list*/ +@d eTeX_aux cur_list.eTeX_aux_field /*auxiliary data for \eTeX*/ +@d LR_save eTeX_aux /*LR stack when a paragraph is interrupted*/ +@d LR_box eTeX_aux /*prototype box for display*/ +@d delim_ptr eTeX_aux /*most recent left or right noad of a math left group*/ +@d prev_graf cur_list.pg_field /*number of paragraph lines accumulated*/ +@d aux cur_list.aux_field /*auxiliary data about the current list*/ +@d prev_depth aux.sc /*the name of |aux| in vertical mode*/ +@d space_factor aux.hh.lh /*part of |aux| in horizontal mode*/ +@d clang aux.hh.rh /*the other part of |aux| in horizontal mode*/ +@d incompleat_noad aux.i /*the name of |aux| in math mode*/ +@d mode_line cur_list.ml_field /*source file line number at beginning of list*/ + +@<Glob...@>= +list_state_record @!nest[nest_size+1]; +int @!nest_ptr; /*first unused location of |nest|*/ +static int @!max_nest_stack; /*maximum of |nest_ptr| when pushing*/ +list_state_record @!cur_list; /*the ``top'' semantic state*/ +static int @!shown_mode; /*most recent mode shown by \.{\\tracingcommands}*/ + +@ Here is a common way to make the current list grow: + +@d tail_append(A) {@+link(tail)=A;tail=link(tail); + } + +@ We will see later that the vertical list at the bottom semantic level is split +into two parts; the ``current page'' runs from |page_head| to |page_tail|, +and the ``contribution list'' runs from |contrib_head| to |tail| of +semantic level zero. The idea is that contributions are first formed in +vertical mode, then ``contributed'' to the current page (during which time +the page-breaking decisions are made). For now, we don't need to know +any more details about the page-building process. + +@<Set init...@>= +nest_ptr=0;max_nest_stack=0; +mode=vmode;head=contrib_head;tail=contrib_head; +eTeX_aux=null; +prev_depth=ignore_depth;mode_line=0; +prev_graf=0;shown_mode=0; +@<Start a new current page@>; + +@ When \TeX's work on one level is interrupted, the state is saved by +calling |push_nest|. This routine changes |head| and |tail| so that +a new (empty) list is begun; it does not change |mode| or |aux|. + +@p void push_nest(void) /*enter a new semantic level, save the old*/ +{@+if (nest_ptr > max_nest_stack) + {@+max_nest_stack=nest_ptr; + if (nest_ptr==nest_size) overflow("semantic nest size", nest_size); +@:TeX capacity exceeded semantic nest size}{\quad semantic nest size@> + } +nest[nest_ptr]=cur_list; /*stack the record*/ +incr(nest_ptr);head=get_avail();tail=head;prev_graf=0;mode_line=line; +eTeX_aux=null; +} + +@ Conversely, when \TeX\ is finished on the current level, the former +state is restored by calling |pop_nest|. This routine will never be +called at the lowest semantic level, nor will it be called unless |head| +is a node that should be returned to free memory. + +@p void pop_nest(void) /*leave a semantic level, re-enter the old*/ +{@+free_avail(head);decr(nest_ptr);cur_list=nest[nest_ptr]; +} + +@ Here is a procedure that displays what \TeX\ is working on, at all levels. + +@p static void print_totals(void); +static void show_activities(void) +{@+int p; /*index into |nest|*/ +int @!m; /*mode*/ +memory_word @!a; /*auxiliary*/ +pointer @!q, @!r; /*for showing the current page*/ +int @!t; /*ditto*/ +nest[nest_ptr]=cur_list; /*put the top level into the array*/ +print_nl("");print_ln(); +for (p=nest_ptr; p>=0; p--) + {@+m=nest[p].mode_field;a=nest[p].aux_field; + print_nl("### ");print_mode(m); + print(" entered at line ");print_int(abs(nest[p].ml_field)); + if (m==hmode) if (nest[p].pg_field!=040600000) + {@+print(" (language");print_int(nest[p].pg_field%0200000); + print(":hyphenmin");print_int(nest[p].pg_field/020000000); + print_char(',');print_int((nest[p].pg_field/0200000)%0100); + print_char(')'); + } + if (nest[p].ml_field < 0) print(" (\\output routine)"); + if (p==0) + {@+@<Show the status of the current page@>; + if (link(contrib_head)!=null) + print_nl("### recent contributions:"); + } + show_box(link(nest[p].head_field)); + @<Show the auxiliary field, |a|@>; + } +} + +@ @<Show the auxiliary...@>= +switch (abs(m)/(max_command+1)) { +case 0: {@+print_nl("prevdepth "); + if (a.sc <= ignore_depth) + { if (a.sc <= unknown_depth) print("unknown"); else print("ignored"); } + else print_scaled(a.sc); + if (nest[p].pg_field!=0) + {@+print(", prevgraf "); + print_int(nest[p].pg_field);print(" line"); + if (nest[p].pg_field!=1) print_char('s'); + } + } @+break; +case 1: {@+print_nl("spacefactor ");print_int(a.hh.lh); + if (m > 0) @+if (a.hh.rh > 0) + {@+print(", current language ");print_int(a.hh.rh);@+ + } + } @+break; +case 2: if (a.i!=null) + {@+print("this will be denominator of:");show_box(a.i);@+ + } +} /*there are no other cases*/ + +@* The table of equivalents. +Now that we have studied the data structures for \TeX's semantic routines, +we ought to consider the data structures used by its syntactic routines. In +other words, our next concern will be +the tables that \TeX\ looks at when it is scanning +what the user has written. + +The biggest and most important such table is called |eqtb|. It holds the +current ``equivalents'' of things; i.e., it explains what things mean +or what their current values are, for all quantities that are subject to +the nesting structure provided by \TeX's grouping mechanism. There are six +parts to |eqtb|: + +\yskip\hangg 1) |eqtb[active_base dotdot(hash_base-1)]| holds the current +equivalents of single-character control sequences. + +\yskip\hangg 2) |eqtb[hash_base dotdot(glue_base-1)]| holds the current +equivalents of multiletter control sequences. + +\yskip\hangg 3) |eqtb[glue_base dotdot(local_base-1)]| holds the current +equivalents of glue parameters like the current baselineskip. + +\yskip\hangg 4) |eqtb[local_base dotdot(int_base-1)]| holds the current +equivalents of local halfword quantities like the current box registers, +the current ``catcodes,'' the current font, and a pointer to the current +paragraph shape. + +\yskip\hangg 5) |eqtb[int_base dotdot(dimen_base-1)]| holds the current +equivalents of fullword integer parameters like the current hyphenation +penalty. + +\yskip\hangg 6) |eqtb[dimen_base dotdot eqtb_size]| holds the current equivalents +of fullword dimension parameters like the current hsize or amount of +hanging indentation. + +\yskip\noindent Note that, for example, the current amount of +baselineskip glue is determined by the setting of a particular location +in region~3 of |eqtb|, while the current meaning of the control sequence +`\.{\\baselineskip}' (which might have been changed by \.{\\def} or +\.{\\let}) appears in region~2. + +@ Each entry in |eqtb| is a |memory_word|. Most of these words are of type +|two_halves|, and subdivided into three fields: + +\yskip\hangg 1) The |eq_level| (a quarterword) is the level of grouping at +which this equivalent was defined. If the level is |level_zero|, the +equivalent has never been defined; |level_one| refers to the outer level +(outside of all groups), and this level is also used for global +definitions that never go away. Higher levels are for equivalents that +will disappear at the end of their group. @^global definitions@> + +\yskip\hangg 2) The |eq_type| (another quarterword) specifies what kind of +entry this is. There are many types, since each \TeX\ primitive like +\.{\\hbox}, \.{\\def}, etc., has its own special code. The list of +command codes above includes all possible settings of the |eq_type| field. + +\yskip\hangg 3) The |equiv| (a halfword) is the current equivalent value. +This may be a font number, a pointer into |mem|, or a variety of other +things. + +@d eq_level_field(A) A.hh.b1 +@d eq_type_field(A) A.hh.b0 +@d equiv_field(A) A.hh.rh +@d eq_level(A) eq_level_field(eqtb[A]) /*level of definition*/ +@d eq_type(A) eq_type_field(eqtb[A]) /*command code for equivalent*/ +@d equiv(A) equiv_field(eqtb[A]) /*equivalent value*/ +@d level_zero min_quarterword /*level for undefined quantities*/ +@d level_one (level_zero+1) /*outermost level for defined quantities*/ + +@ Many locations in |eqtb| have symbolic names. The purpose of the next +paragraphs is to define these names, and to set up the initial values of the +equivalents. + +In the first region we have 256 equivalents for ``active characters'' that +act as control sequences, followed by 256 equivalents for single-character +control sequences. + +Then comes region~2, which corresponds to the hash table that we will +define later. The maximum address in this region is used for a dummy +control sequence that is perpetually undefined. There also are several +locations for control sequences that are perpetually defined +(since they are used in error recovery). + +@d active_base 1 /*beginning of region 1, for active character equivalents*/ +@d single_base (active_base+256) /*equivalents of one-character control sequences*/ +@d null_cs (single_base+256) /*equivalent of \.{\\csname\\endcsname}*/ +@d hash_base (null_cs+1) /*beginning of region 2, for the hash table*/ +@d frozen_control_sequence (hash_base+hash_size) /*for error recovery*/ +@d frozen_protection frozen_control_sequence /*inaccessible but definable*/ +@d frozen_cr (frozen_control_sequence+1) /*permanent `\.{\\cr}'*/ +@d frozen_end_group (frozen_control_sequence+2) /*permanent `\.{\\endgroup}'*/ +@d frozen_right (frozen_control_sequence+3) /*permanent `\.{\\right}'*/ +@d frozen_fi (frozen_control_sequence+4) /*permanent `\.{\\fi}'*/ +@d frozen_end_template (frozen_control_sequence+5) /*permanent `\.{\\endtemplate}'*/ +@d frozen_endv (frozen_control_sequence+6) /*second permanent `\.{\\endtemplate}'*/ +@d frozen_relax (frozen_control_sequence+7) /*permanent `\.{\\relax}'*/ +@d end_write (frozen_control_sequence+8) /*permanent `\.{\\endwrite}'*/ +@d frozen_dont_expand (frozen_control_sequence+9) + /*permanent `\.{\\notexpanded:}'*/ +@d frozen_null_font (frozen_control_sequence+10) + /*permanent `\.{\\nullfont}'*/ +@d font_id_base (frozen_null_font-font_base) + /*begins table of 257 permanent font identifiers*/ +@d undefined_control_sequence (frozen_null_font+257) /*dummy location*/ +@d glue_base (undefined_control_sequence+1) /*beginning of region 3*/ + +@<Initialize table entries...@>= +eq_type(undefined_control_sequence)=undefined_cs; +equiv(undefined_control_sequence)=null; +eq_level(undefined_control_sequence)=level_zero; +for (k=active_base; k<=undefined_control_sequence-1; k++) + eqtb[k]=eqtb[undefined_control_sequence]; + +@ Here is a routine that displays the current meaning of an |eqtb| entry +in region 1 or~2. (Similar routines for the other regions will appear +below.) + +@<Show equivalent |n|, in region 1 or 2@>= +{@+sprint_cs(n);print_char('=');print_cmd_chr(eq_type(n), equiv(n)); +if (eq_type(n) >= call) + {@+print_char(':');show_token_list(link(equiv(n)), null, 32); + } +} + +@ Region 3 of |eqtb| contains the 256 \.{\\skip} registers, as well as the +glue parameters defined here. It is important that the ``muskip'' +parameters have larger numbers than the others. + +@d line_skip_code 0 /*interline glue if |baseline_skip| is infeasible*/ +@d baseline_skip_code 1 /*desired glue between baselines*/ +@d par_skip_code 2 /*extra glue just above a paragraph*/ +@d above_display_skip_code 3 /*extra glue just above displayed math*/ +@d below_display_skip_code 4 /*extra glue just below displayed math*/ +@d above_display_short_skip_code 5 + /*glue above displayed math following short lines*/ +@d below_display_short_skip_code 6 + /*glue below displayed math following short lines*/ +@d left_skip_code 7 /*glue at left of justified lines*/ +@d right_skip_code 8 /*glue at right of justified lines*/ +@d top_skip_code 9 /*glue at top of main pages*/ +@d split_top_skip_code 10 /*glue at top of split pages*/ +@d tab_skip_code 11 /*glue between aligned entries*/ +@d space_skip_code 12 /*glue between words (if not |zero_glue|)*/ +@d xspace_skip_code 13 /*glue after sentences (if not |zero_glue|)*/ +@d par_fill_skip_code 14 /*glue on last line of paragraph*/ +@d thin_mu_skip_code 15 /*thin space in math formula*/ +@d med_mu_skip_code 16 /*medium space in math formula*/ +@d thick_mu_skip_code 17 /*thick space in math formula*/ +@d glue_pars 18 /*total number of glue parameters*/ +@d skip_base (glue_base+glue_pars) /*table of 256 ``skip'' registers*/ +@d mu_skip_base (skip_base+256) /*table of 256 ``muskip'' registers*/ +@d local_base (mu_skip_base+256) /*beginning of region 4*/ +@# +@d skip(A) equiv(skip_base+A) /*|mem| location of glue specification*/ +@d mu_skip(A) equiv(mu_skip_base+A) /*|mem| location of math glue spec*/ +@d glue_par(A) equiv(glue_base+A) /*|mem| location of glue specification*/ +@d line_skip glue_par(line_skip_code) +@d baseline_skip glue_par(baseline_skip_code) +@d par_skip glue_par(par_skip_code) +@d above_display_skip glue_par(above_display_skip_code) +@d below_display_skip glue_par(below_display_skip_code) +@d above_display_short_skip glue_par(above_display_short_skip_code) +@d below_display_short_skip glue_par(below_display_short_skip_code) +@d left_skip glue_par(left_skip_code) +@d right_skip glue_par(right_skip_code) +@d top_skip glue_par(top_skip_code) +@d split_top_skip glue_par(split_top_skip_code) +@d tab_skip glue_par(tab_skip_code) +@d space_skip glue_par(space_skip_code) +@d xspace_skip glue_par(xspace_skip_code) +@d par_fill_skip glue_par(par_fill_skip_code) +@d thin_mu_skip glue_par(thin_mu_skip_code) +@d med_mu_skip glue_par(med_mu_skip_code) +@d thick_mu_skip glue_par(thick_mu_skip_code) + +@<Current |mem| equivalent of glue parameter number |n|@>=glue_par(n) + +@ Sometimes we need to convert \TeX's internal code numbers into symbolic +form. The |print_skip_param| routine gives the symbolic name of a glue +parameter. + +@<Declare the procedure called |print_skip_param|@>= +static void print_skip_param(int @!n) +{@+switch (n) { +case line_skip_code: print_esc("lineskip");@+break; +case baseline_skip_code: print_esc("baselineskip");@+break; +case par_skip_code: print_esc("parskip");@+break; +case above_display_skip_code: print_esc("abovedisplayskip");@+break; +case below_display_skip_code: print_esc("belowdisplayskip");@+break; +case above_display_short_skip_code: print_esc("abovedisplayshortskip");@+break; +case below_display_short_skip_code: print_esc("belowdisplayshortskip");@+break; +case left_skip_code: print_esc("leftskip");@+break; +case right_skip_code: print_esc("rightskip");@+break; +case top_skip_code: print_esc("topskip");@+break; +case split_top_skip_code: print_esc("splittopskip");@+break; +case tab_skip_code: print_esc("tabskip");@+break; +case space_skip_code: print_esc("spaceskip");@+break; +case xspace_skip_code: print_esc("xspaceskip");@+break; +case par_fill_skip_code: print_esc("parfillskip");@+break; +case thin_mu_skip_code: print_esc("thinmuskip");@+break; +case med_mu_skip_code: print_esc("medmuskip");@+break; +case thick_mu_skip_code: print_esc("thickmuskip");@+break; +default:print("[unknown glue parameter!]"); +} +} + +@ The symbolic names for glue parameters are put into \TeX's hash table +by using the routine called |primitive|, defined below. Let us enter them +now, so that we don't have to list all those parameter names anywhere else. + +@<Put each of \TeX's primitives into the hash table@>= +primitive("lineskip", assign_glue, glue_base+line_skip_code);@/ +@!@:line\_skip\_}{\.{\\lineskip} primitive@> +primitive("baselineskip", assign_glue, glue_base+baseline_skip_code);@/ +@!@:baseline\_skip\_}{\.{\\baselineskip} primitive@> +primitive("parskip", assign_glue, glue_base+par_skip_code);@/ +@!@:par\_skip\_}{\.{\\parskip} primitive@> +primitive("abovedisplayskip", assign_glue, glue_base+above_display_skip_code);@/ +@!@:above\_display\_skip\_}{\.{\\abovedisplayskip} primitive@> +primitive("belowdisplayskip", assign_glue, glue_base+below_display_skip_code);@/ +@!@:below\_display\_skip\_}{\.{\\belowdisplayskip} primitive@> +primitive("abovedisplayshortskip", + assign_glue, glue_base+above_display_short_skip_code);@/ +@!@:above\_display\_short\_skip\_}{\.{\\abovedisplayshortskip} primitive@> +primitive("belowdisplayshortskip", + assign_glue, glue_base+below_display_short_skip_code);@/ +@!@:below\_display\_short\_skip\_}{\.{\\belowdisplayshortskip} primitive@> +primitive("leftskip", assign_glue, glue_base+left_skip_code);@/ +@!@:left\_skip\_}{\.{\\leftskip} primitive@> +primitive("rightskip", assign_glue, glue_base+right_skip_code);@/ +@!@:right\_skip\_}{\.{\\rightskip} primitive@> +primitive("topskip", assign_glue, glue_base+top_skip_code);@/ +@!@:top\_skip\_}{\.{\\topskip} primitive@> +primitive("splittopskip", assign_glue, glue_base+split_top_skip_code);@/ +@!@:split\_top\_skip\_}{\.{\\splittopskip} primitive@> +primitive("tabskip", assign_glue, glue_base+tab_skip_code);@/ +@!@:tab\_skip\_}{\.{\\tabskip} primitive@> +primitive("spaceskip", assign_glue, glue_base+space_skip_code);@/ +@!@:space\_skip\_}{\.{\\spaceskip} primitive@> +primitive("xspaceskip", assign_glue, glue_base+xspace_skip_code);@/ +@!@:xspace\_skip\_}{\.{\\xspaceskip} primitive@> +primitive("parfillskip", assign_glue, glue_base+par_fill_skip_code);@/ +@!@:par\_fill\_skip\_}{\.{\\parfillskip} primitive@> +primitive("thinmuskip", assign_mu_glue, glue_base+thin_mu_skip_code);@/ +@!@:thin\_mu\_skip\_}{\.{\\thinmuskip} primitive@> +primitive("medmuskip", assign_mu_glue, glue_base+med_mu_skip_code);@/ +@!@:med\_mu\_skip\_}{\.{\\medmuskip} primitive@> +primitive("thickmuskip", assign_mu_glue, glue_base+thick_mu_skip_code);@/ +@!@:thick\_mu\_skip\_}{\.{\\thickmuskip} primitive@> + +@ @<Cases of |print_cmd_chr| for symbolic printing of primitives@>= +case assign_glue: case assign_mu_glue: if (chr_code < skip_base) + print_skip_param(chr_code-glue_base); + else if (chr_code < mu_skip_base) + {@+print_esc("skip");print_int(chr_code-skip_base); + } + else{@+print_esc("muskip");print_int(chr_code-mu_skip_base); + } @+break; + +@ All glue parameters and registers are initially `\.{0pt plus0pt minus0pt}'. + +@<Initialize table entries...@>= +equiv(glue_base)=zero_glue;eq_level(glue_base)=level_one; +eq_type(glue_base)=glue_ref; +for (k=glue_base+1; k<=local_base-1; k++) eqtb[k]=eqtb[glue_base]; +glue_ref_count(zero_glue)=glue_ref_count(zero_glue)+local_base-glue_base; + +@ @<Show equivalent |n|, in region 3@>= +if (n < skip_base) + {@+print_skip_param(n-glue_base);print_char('='); + if (n < glue_base+thin_mu_skip_code) print_spec(equiv(n),"pt"); + else print_spec(equiv(n),"mu"); + } +else if (n < mu_skip_base) + {@+print_esc("skip");print_int(n-skip_base);print_char('='); + print_spec(equiv(n),"pt"); + } +else{@+print_esc("muskip");print_int(n-mu_skip_base);print_char('='); + print_spec(equiv(n),"mu"); + } + +@ Region 4 of |eqtb| contains the local quantities defined here. The +bulk of this region is taken up by five tables that are indexed by eight-bit +characters; these tables are important to both the syntactic and semantic +portions of \TeX. There are also a bunch of special things like font and +token parameters, as well as the tables of \.{\\toks} and \.{\\box} +registers. + +@d par_shape_loc local_base /*specifies paragraph shape*/ +@d output_routine_loc (local_base+1) /*points to token list for \.{\\output}*/ +@d every_par_loc (local_base+2) /*points to token list for \.{\\everypar}*/ +@d every_math_loc (local_base+3) /*points to token list for \.{\\everymath}*/ +@d every_display_loc (local_base+4) /*points to token list for \.{\\everydisplay}*/ +@d every_hbox_loc (local_base+5) /*points to token list for \.{\\everyhbox}*/ +@d every_vbox_loc (local_base+6) /*points to token list for \.{\\everyvbox}*/ +@d every_job_loc (local_base+7) /*points to token list for \.{\\everyjob}*/ +@d every_cr_loc (local_base+8) /*points to token list for \.{\\everycr}*/ +@d err_help_loc (local_base+9) /*points to token list for \.{\\errhelp}*/ +@d tex_toks (local_base+10) /*end of \TeX's token list parameters*/ +@# +@d etex_toks_base tex_toks /*base for \eTeX's token list parameters*/ +@d every_eof_loc etex_toks_base /*points to token list for \.{\\everyeof}*/ +@d etex_toks (etex_toks_base+1) /*end of \eTeX's token list parameters*/ +@# +@d toks_base etex_toks /*table of 256 token list registers*/ +@# +@d etex_pen_base (toks_base+256) /*start of table of \eTeX's penalties*/ +@d inter_line_penalties_loc etex_pen_base /*additional penalties between lines*/ +@d club_penalties_loc (etex_pen_base+1) /*penalties for creating club lines*/ +@d widow_penalties_loc (etex_pen_base+2) /*penalties for creating widow lines*/ +@d display_widow_penalties_loc (etex_pen_base+3) /*ditto, just before a display*/ +@d etex_pens (etex_pen_base+4) /*end of table of \eTeX's penalties*/ +@# +@d box_base etex_pens /*table of 256 box registers*/ +@d cur_font_loc (box_base+256) /*internal font number outside math mode*/ +@d math_font_base (cur_font_loc+1) /*table of 48 math font numbers*/ +@d cat_code_base (math_font_base+48) + /*table of 256 command codes (the ``catcodes'')*/ +@d lc_code_base (cat_code_base+256) /*table of 256 lowercase mappings*/ +@d uc_code_base (lc_code_base+256) /*table of 256 uppercase mappings*/ +@d sf_code_base (uc_code_base+256) /*table of 256 spacefactor mappings*/ +@d math_code_base (sf_code_base+256) /*table of 256 math mode mappings*/ +@d int_base (math_code_base+256) /*beginning of region 5*/ +@# +@d par_shape_ptr equiv(par_shape_loc) +@d output_routine equiv(output_routine_loc) +@d every_par equiv(every_par_loc) +@d every_math equiv(every_math_loc) +@d every_display equiv(every_display_loc) +@d every_hbox equiv(every_hbox_loc) +@d every_vbox equiv(every_vbox_loc) +@d every_job equiv(every_job_loc) +@d every_cr equiv(every_cr_loc) +@d err_help equiv(err_help_loc) +@d toks(X) equiv(toks_base+X) +@d box(A) equiv(box_base+A) +@d cur_font equiv(cur_font_loc) +@d fam_fnt(A) equiv(math_font_base+A) +@d cat_code(A) equiv(cat_code_base+A) +@d lc_code(A) equiv(lc_code_base+A) +@d uc_code(A) equiv(uc_code_base+A) +@d sf_code(A) equiv(sf_code_base+A) +@d math_code(A) equiv(math_code_base+A) + /*Note: |math_code(c)| is the true math code plus |min_halfword|*/ + +@<Put each...@>= +primitive("output", assign_toks, output_routine_loc); +@!@:output\_}{\.{\\output} primitive@> +primitive("everypar", assign_toks, every_par_loc); +@!@:every\_par\_}{\.{\\everypar} primitive@> +primitive("everymath", assign_toks, every_math_loc); +@!@:every\_math\_}{\.{\\everymath} primitive@> +primitive("everydisplay", assign_toks, every_display_loc); +@!@:every\_display\_}{\.{\\everydisplay} primitive@> +primitive("everyhbox", assign_toks, every_hbox_loc); +@!@:every\_hbox\_}{\.{\\everyhbox} primitive@> +primitive("everyvbox", assign_toks, every_vbox_loc); +@!@:every\_vbox\_}{\.{\\everyvbox} primitive@> +primitive("everyjob", assign_toks, every_job_loc); +@!@:every\_job\_}{\.{\\everyjob} primitive@> +primitive("everycr", assign_toks, every_cr_loc); +@!@:every\_cr\_}{\.{\\everycr} primitive@> +primitive("errhelp", assign_toks, err_help_loc); +@!@:err\_help\_}{\.{\\errhelp} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case assign_toks: if (chr_code >= toks_base) + {@+print_esc("toks");print_int(chr_code-toks_base); + } +else switch (chr_code) { + case output_routine_loc: print_esc("output");@+break; + case every_par_loc: print_esc("everypar");@+break; + case every_math_loc: print_esc("everymath");@+break; + case every_display_loc: print_esc("everydisplay");@+break; + case every_hbox_loc: print_esc("everyhbox");@+break; + case every_vbox_loc: print_esc("everyvbox");@+break; + case every_job_loc: print_esc("everyjob");@+break; + case every_cr_loc: print_esc("everycr");@+break; + @/@<Cases of |assign_toks| for |print_cmd_chr|@>@/ + default:print_esc("errhelp"); + } @+break; + +@ We initialize most things to null or undefined values. An undefined font +is represented by the internal code |font_base|. + +However, the character code tables are given initial values based on the +conventional interpretation of ASCII code. These initial values should +not be changed when \TeX\ is adapted for use with non-English languages; +all changes to the initialization conventions should be made in format +packages, not in \TeX\ itself, so that global interchange of formats is +possible. + +@d null_font font_base +@d var_code 070000 /*math code meaning ``use the current family''*/ + +@<Initialize table entries...@>= +par_shape_ptr=null;eq_type(par_shape_loc)=shape_ref; +eq_level(par_shape_loc)=level_one;@/ +for (k=etex_pen_base; k<=etex_pens-1; k++) + eqtb[k]=eqtb[par_shape_loc]; +for (k=output_routine_loc; k<=toks_base+255; k++) + eqtb[k]=eqtb[undefined_control_sequence]; +box(0)=null;eq_type(box_base)=box_ref;eq_level(box_base)=level_one; +for (k=box_base+1; k<=box_base+255; k++) eqtb[k]=eqtb[box_base]; +cur_font=null_font;eq_type(cur_font_loc)=data; +eq_level(cur_font_loc)=level_one;@/ +for (k=math_font_base; k<=math_font_base+47; k++) eqtb[k]=eqtb[cur_font_loc]; +equiv(cat_code_base)=0;eq_type(cat_code_base)=data; +eq_level(cat_code_base)=level_one;@/ +for (k=cat_code_base+1; k<=int_base-1; k++) eqtb[k]=eqtb[cat_code_base]; +for (k=0; k<=255; k++) + {@+cat_code(k)=other_char;math_code(k)=hi(k);sf_code(k)=1000; + } +cat_code(carriage_return)=car_ret;cat_code(' ')=spacer; +cat_code('\\')=escape;cat_code('%')=comment; +cat_code(invalid_code)=invalid_char;cat_code(null_code)=ignore; +for (k='0'; k<='9'; k++) math_code(k)=hi(k+var_code); +for (k='A'; k<='Z'; k++) + {@+cat_code(k)=letter;cat_code(k+'a'-'A')=letter;@/ + math_code(k)=hi(k+var_code+0x100); + math_code(k+'a'-'A')=hi(k+'a'-'A'+var_code+0x100);@/ + lc_code(k)=k+'a'-'A';lc_code(k+'a'-'A')=k+'a'-'A';@/ + uc_code(k)=k;uc_code(k+'a'-'A')=k;@/ + sf_code(k)=999; + } + +@ @<Show equivalent |n|, in region 4@>= +if ((n==par_shape_loc)||((n >= etex_pen_base)&&(n < etex_pens))) + {@+print_cmd_chr(set_shape, n);print_char('='); + if (equiv(n)==null) print_char('0'); + else if (n > par_shape_loc) + {@+print_int(penalty(equiv(n)));print_char(' '); + print_int(penalty(equiv(n)+1)); + if (penalty(equiv(n)) > 1) print_esc("ETC."); + } + else print_int(info(par_shape_ptr)); + } +else if (n < toks_base) + {@+print_cmd_chr(assign_toks, n);print_char('='); + if (equiv(n)!=null) show_token_list(link(equiv(n)), null, 32); + } +else if (n < box_base) + {@+print_esc("toks");print_int(n-toks_base);print_char('='); + if (equiv(n)!=null) show_token_list(link(equiv(n)), null, 32); + } +else if (n < cur_font_loc) + {@+print_esc("box");print_int(n-box_base);print_char('='); + if (equiv(n)==null) print("void"); + else{@+depth_threshold=0;breadth_max=1;show_node_list(equiv(n)); + } + } +else if (n < cat_code_base) @<Show the font identifier in |eqtb[n]|@>@; +else@<Show the halfword code in |eqtb[n]|@>@; + +@ @<Show the font identifier in |eqtb[n]|@>= +{@+if (n==cur_font_loc) print("current font"); +else if (n < math_font_base+16) + {@+print_esc("textfont");print_int(n-math_font_base); + } +else if (n < math_font_base+32) + {@+print_esc("scriptfont");print_int(n-math_font_base-16); + } +else{@+print_esc("scriptscriptfont");print_int(n-math_font_base-32); + } +print_char('=');@/ +printn_esc(hash[font_id_base+equiv(n)].rh); + /*that's |font_id_text(equiv(n))|*/ +} + +@ @<Show the halfword code in |eqtb[n]|@>= +if (n < math_code_base) + {@+if (n < lc_code_base) + {@+print_esc("catcode");print_int(n-cat_code_base); + } + else if (n < uc_code_base) + {@+print_esc("lccode");print_int(n-lc_code_base); + } + else if (n < sf_code_base) + {@+print_esc("uccode");print_int(n-uc_code_base); + } + else{@+print_esc("sfcode");print_int(n-sf_code_base); + } + print_char('=');print_int(equiv(n)); + } +else{@+print_esc("mathcode");print_int(n-math_code_base); + print_char('=');print_int(ho(equiv(n))); + } + +@ Region 5 of |eqtb| contains the integer parameters and registers defined +here, as well as the |del_code| table. The latter table differs from the +|cat_code dotdot math_code| tables that precede it, since delimiter codes are +fullword integers while the other kinds of codes occupy at most a +halfword. This is what makes region~5 different from region~4. We will +store the |eq_level| information in an auxiliary array of quarterwords +that will be defined later. + +@d pretolerance_code 0 /*badness tolerance before hyphenation*/ +@d tolerance_code 1 /*badness tolerance after hyphenation*/ +@d line_penalty_code 2 /*added to the badness of every line*/ +@d hyphen_penalty_code 3 /*penalty for break after discretionary hyphen*/ +@d ex_hyphen_penalty_code 4 /*penalty for break after explicit hyphen*/ +@d club_penalty_code 5 /*penalty for creating a club line*/ +@d widow_penalty_code 6 /*penalty for creating a widow line*/ +@d display_widow_penalty_code 7 /*ditto, just before a display*/ +@d broken_penalty_code 8 /*penalty for breaking a page at a broken line*/ +@d bin_op_penalty_code 9 /*penalty for breaking after a binary operation*/ +@d rel_penalty_code 10 /*penalty for breaking after a relation*/ +@d pre_display_penalty_code 11 + /*penalty for breaking just before a displayed formula*/ +@d post_display_penalty_code 12 + /*penalty for breaking just after a displayed formula*/ +@d inter_line_penalty_code 13 /*additional penalty between lines*/ +@d double_hyphen_demerits_code 14 /*demerits for double hyphen break*/ +@d final_hyphen_demerits_code 15 /*demerits for final hyphen break*/ +@d adj_demerits_code 16 /*demerits for adjacent incompatible lines*/ +@d mag_code 17 /*magnification ratio*/ +@d delimiter_factor_code 18 /*ratio for variable-size delimiters*/ +@d looseness_code 19 /*change in number of lines for a paragraph*/ +@d time_code 20 /*current time of day*/ +@d day_code 21 /*current day of the month*/ +@d month_code 22 /*current month of the year*/ +@d year_code 23 /*current year of our Lord*/ +@d show_box_breadth_code 24 /*nodes per level in |show_box|*/ +@d show_box_depth_code 25 /*maximum level in |show_box|*/ +@d hbadness_code 26 /*hboxes exceeding this badness will be shown by |hpack|*/ +@d vbadness_code 27 /*vboxes exceeding this badness will be shown by |vpack|*/ +@d pausing_code 28 /*pause after each line is read from a file*/ +@d tracing_online_code 29 /*show diagnostic output on terminal*/ +@d tracing_macros_code 30 /*show macros as they are being expanded*/ +@d tracing_stats_code 31 /*show memory usage if \TeX\ knows it*/ +@d tracing_paragraphs_code 32 /*show line-break calculations*/ +@d tracing_pages_code 33 /*show page-break calculations*/ +@d tracing_output_code 34 /*show boxes when they are shipped out*/ +@d tracing_lost_chars_code 35 /*show characters that aren't in the font*/ +@d tracing_commands_code 36 /*show command codes at |big_switch|*/ +@d tracing_restores_code 37 /*show equivalents when they are restored*/ +@d uc_hyph_code 38 /*hyphenate words beginning with a capital letter*/ +@d output_penalty_code 39 /*penalty found at current page break*/ +@d max_dead_cycles_code 40 /*bound on consecutive dead cycles of output*/ +@d hang_after_code 41 /*hanging indentation changes after this many lines*/ +@d floating_penalty_code 42 /*penalty for insertions heldover after a split*/ +@d global_defs_code 43 /*override \.{\\global} specifications*/ +@d cur_fam_code 44 /*current family*/ +@d escape_char_code 45 /*escape character for token output*/ +@d default_hyphen_char_code 46 /*value of \.{\\hyphenchar} when a font is loaded*/ +@d default_skew_char_code 47 /*value of \.{\\skewchar} when a font is loaded*/ +@d end_line_char_code 48 /*character placed at the right end of the buffer*/ +@d new_line_char_code 49 /*character that prints as |print_ln|*/ +@d language_code 50 /*current hyphenation table*/ +@d left_hyphen_min_code 51 /*minimum left hyphenation fragment size*/ +@d right_hyphen_min_code 52 /*minimum right hyphenation fragment size*/ +@d holding_inserts_code 53 /*do not remove insertion nodes from \.{\\box255}*/ +@d error_context_lines_code 54 /*maximum intermediate line pairs shown*/ +@d tex_int_pars 55 /*total number of \TeX's integer parameters*/ +@# +@d etex_int_base tex_int_pars /*base for \eTeX's integer parameters*/ +@d tracing_assigns_code etex_int_base /*show assignments*/ +@d tracing_groups_code (etex_int_base+1) /*show save/restore groups*/ +@d tracing_ifs_code (etex_int_base+2) /*show conditionals*/ +@d tracing_scan_tokens_code (etex_int_base+3) /*show pseudo file open and close*/ +@d tracing_nesting_code (etex_int_base+4) /*show incomplete groups and ifs within files*/ +@d eTeX_state_code (etex_int_base+5) /*\eTeX\ state variables*/ +@d etex_int_pars (eTeX_state_code+eTeX_states) /*total number of \eTeX's integer parameters*/ +@# +@d int_pars etex_int_pars /*total number of integer parameters*/ +@d count_base (int_base+int_pars) /*256 user \.{\\count} registers*/ +@d del_code_base (count_base+256) /*256 delimiter code mappings*/ +@d dimen_base (del_code_base+256) /*beginning of region 6*/ +@# +@d del_code(A) eqtb[del_code_base+A].i +@d count(A) eqtb[count_base+A].i +@d int_par(A) eqtb[int_base+A].i /*an integer parameter*/ +@d pretolerance int_par(pretolerance_code) +@d tolerance int_par(tolerance_code) +@d line_penalty int_par(line_penalty_code) +@d hyphen_penalty int_par(hyphen_penalty_code) +@d ex_hyphen_penalty int_par(ex_hyphen_penalty_code) +@d club_penalty int_par(club_penalty_code) +@d widow_penalty int_par(widow_penalty_code) +@d display_widow_penalty int_par(display_widow_penalty_code) +@d broken_penalty int_par(broken_penalty_code) +@d bin_op_penalty int_par(bin_op_penalty_code) +@d rel_penalty int_par(rel_penalty_code) +@d pre_display_penalty int_par(pre_display_penalty_code) +@d post_display_penalty int_par(post_display_penalty_code) +@d inter_line_penalty int_par(inter_line_penalty_code) +@d double_hyphen_demerits int_par(double_hyphen_demerits_code) +@d final_hyphen_demerits int_par(final_hyphen_demerits_code) +@d adj_demerits int_par(adj_demerits_code) +@d mag int_par(mag_code) +@d delimiter_factor int_par(delimiter_factor_code) +@d looseness int_par(looseness_code) +@d time int_par(time_code) +@d day int_par(day_code) +@d month int_par(month_code) +@d year int_par(year_code) +@d show_box_breadth int_par(show_box_breadth_code) +@d show_box_depth int_par(show_box_depth_code) +@d hbadness int_par(hbadness_code) +@d vbadness int_par(vbadness_code) +@d pausing int_par(pausing_code) +@d tracing_online int_par(tracing_online_code) +@d tracing_macros int_par(tracing_macros_code) +@d tracing_stats int_par(tracing_stats_code) +@d tracing_paragraphs int_par(tracing_paragraphs_code) +@d tracing_pages int_par(tracing_pages_code) +@d tracing_output int_par(tracing_output_code) +@d tracing_lost_chars int_par(tracing_lost_chars_code) +@d tracing_commands int_par(tracing_commands_code) +@d tracing_restores int_par(tracing_restores_code) +@d uc_hyph int_par(uc_hyph_code) +@d output_penalty int_par(output_penalty_code) +@d max_dead_cycles int_par(max_dead_cycles_code) +@d hang_after int_par(hang_after_code) +@d floating_penalty int_par(floating_penalty_code) +@d global_defs int_par(global_defs_code) +@d cur_fam int_par(cur_fam_code) +@d escape_char int_par(escape_char_code) +@d default_hyphen_char int_par(default_hyphen_char_code) +@d default_skew_char int_par(default_skew_char_code) +@d end_line_char int_par(end_line_char_code) +@d new_line_char int_par(new_line_char_code) +@d language int_par(language_code) +@d left_hyphen_min int_par(left_hyphen_min_code) +@d right_hyphen_min int_par(right_hyphen_min_code) +@d holding_inserts int_par(holding_inserts_code) +@d error_context_lines int_par(error_context_lines_code) +@# +@d tracing_assigns int_par(tracing_assigns_code) +@d tracing_groups int_par(tracing_groups_code) +@d tracing_ifs int_par(tracing_ifs_code) +@d tracing_scan_tokens int_par(tracing_scan_tokens_code) +@d tracing_nesting int_par(tracing_nesting_code) + +@<Assign the values |depth_threshold:=show_box_depth|...@>= +depth_threshold=show_box_depth; +breadth_max=show_box_breadth + +@ We can print the symbolic name of an integer parameter as follows. + +@p static void print_param(int @!n) +{@+switch (n) { +case pretolerance_code: print_esc("pretolerance");@+break; +case tolerance_code: print_esc("tolerance");@+break; +case line_penalty_code: print_esc("linepenalty");@+break; +case hyphen_penalty_code: print_esc("hyphenpenalty");@+break; +case ex_hyphen_penalty_code: print_esc("exhyphenpenalty");@+break; +case club_penalty_code: print_esc("clubpenalty");@+break; +case widow_penalty_code: print_esc("widowpenalty");@+break; +case display_widow_penalty_code: print_esc("displaywidowpenalty");@+break; +case broken_penalty_code: print_esc("brokenpenalty");@+break; +case bin_op_penalty_code: print_esc("binoppenalty");@+break; +case rel_penalty_code: print_esc("relpenalty");@+break; +case pre_display_penalty_code: print_esc("predisplaypenalty");@+break; +case post_display_penalty_code: print_esc("postdisplaypenalty");@+break; +case inter_line_penalty_code: print_esc("interlinepenalty");@+break; +case double_hyphen_demerits_code: print_esc("doublehyphendemerits");@+break; +case final_hyphen_demerits_code: print_esc("finalhyphendemerits");@+break; +case adj_demerits_code: print_esc("adjdemerits");@+break; +case mag_code: print_esc("mag");@+break; +case delimiter_factor_code: print_esc("delimiterfactor");@+break; +case looseness_code: print_esc("looseness");@+break; +case time_code: print_esc("time");@+break; +case day_code: print_esc("day");@+break; +case month_code: print_esc("month");@+break; +case year_code: print_esc("year");@+break; +case show_box_breadth_code: print_esc("showboxbreadth");@+break; +case show_box_depth_code: print_esc("showboxdepth");@+break; +case hbadness_code: print_esc("hbadness");@+break; +case vbadness_code: print_esc("vbadness");@+break; +case pausing_code: print_esc("pausing");@+break; +case tracing_online_code: print_esc("tracingonline");@+break; +case tracing_macros_code: print_esc("tracingmacros");@+break; +case tracing_stats_code: print_esc("tracingstats");@+break; +case tracing_paragraphs_code: print_esc("tracingparagraphs");@+break; +case tracing_pages_code: print_esc("tracingpages");@+break; +case tracing_output_code: print_esc("tracingoutput");@+break; +case tracing_lost_chars_code: print_esc("tracinglostchars");@+break; +case tracing_commands_code: print_esc("tracingcommands");@+break; +case tracing_restores_code: print_esc("tracingrestores");@+break; +case uc_hyph_code: print_esc("uchyph");@+break; +case output_penalty_code: print_esc("outputpenalty");@+break; +case max_dead_cycles_code: print_esc("maxdeadcycles");@+break; +case hang_after_code: print_esc("hangafter");@+break; +case floating_penalty_code: print_esc("floatingpenalty");@+break; +case global_defs_code: print_esc("globaldefs");@+break; +case cur_fam_code: print_esc("fam");@+break; +case escape_char_code: print_esc("escapechar");@+break; +case default_hyphen_char_code: print_esc("defaulthyphenchar");@+break; +case default_skew_char_code: print_esc("defaultskewchar");@+break; +case end_line_char_code: print_esc("endlinechar");@+break; +case new_line_char_code: print_esc("newlinechar");@+break; +case language_code: print_esc("language");@+break; +case left_hyphen_min_code: print_esc("lefthyphenmin");@+break; +case right_hyphen_min_code: print_esc("righthyphenmin");@+break; +case holding_inserts_code: print_esc("holdinginserts");@+break; +case error_context_lines_code: print_esc("errorcontextlines");@+break; +@/@<Cases for |print_param|@>@/ +default:print("[unknown integer parameter!]"); +} +} + +@ The integer parameter names must be entered into the hash table. + +@<Put each...@>= +primitive("pretolerance", assign_int, int_base+pretolerance_code);@/ +@!@:pretolerance\_}{\.{\\pretolerance} primitive@> +primitive("tolerance", assign_int, int_base+tolerance_code);@/ +@!@:tolerance\_}{\.{\\tolerance} primitive@> +primitive("linepenalty", assign_int, int_base+line_penalty_code);@/ +@!@:line\_penalty\_}{\.{\\linepenalty} primitive@> +primitive("hyphenpenalty", assign_int, int_base+hyphen_penalty_code);@/ +@!@:hyphen\_penalty\_}{\.{\\hyphenpenalty} primitive@> +primitive("exhyphenpenalty", assign_int, int_base+ex_hyphen_penalty_code);@/ +@!@:ex\_hyphen\_penalty\_}{\.{\\exhyphenpenalty} primitive@> +primitive("clubpenalty", assign_int, int_base+club_penalty_code);@/ +@!@:club\_penalty\_}{\.{\\clubpenalty} primitive@> +primitive("widowpenalty", assign_int, int_base+widow_penalty_code);@/ +@!@:widow\_penalty\_}{\.{\\widowpenalty} primitive@> +primitive("displaywidowpenalty", + assign_int, int_base+display_widow_penalty_code);@/ +@!@:display\_widow\_penalty\_}{\.{\\displaywidowpenalty} primitive@> +primitive("brokenpenalty", assign_int, int_base+broken_penalty_code);@/ +@!@:broken\_penalty\_}{\.{\\brokenpenalty} primitive@> +primitive("binoppenalty", assign_int, int_base+bin_op_penalty_code);@/ +@!@:bin\_op\_penalty\_}{\.{\\binoppenalty} primitive@> +primitive("relpenalty", assign_int, int_base+rel_penalty_code);@/ +@!@:rel\_penalty\_}{\.{\\relpenalty} primitive@> +primitive("predisplaypenalty", assign_int, int_base+pre_display_penalty_code);@/ +@!@:pre\_display\_penalty\_}{\.{\\predisplaypenalty} primitive@> +primitive("postdisplaypenalty", assign_int, int_base+post_display_penalty_code);@/ +@!@:post\_display\_penalty\_}{\.{\\postdisplaypenalty} primitive@> +primitive("interlinepenalty", assign_int, int_base+inter_line_penalty_code);@/ +@!@:inter\_line\_penalty\_}{\.{\\interlinepenalty} primitive@> +primitive("doublehyphendemerits", + assign_int, int_base+double_hyphen_demerits_code);@/ +@!@:double\_hyphen\_demerits\_}{\.{\\doublehyphendemerits} primitive@> +primitive("finalhyphendemerits", + assign_int, int_base+final_hyphen_demerits_code);@/ +@!@:final\_hyphen\_demerits\_}{\.{\\finalhyphendemerits} primitive@> +primitive("adjdemerits", assign_int, int_base+adj_demerits_code);@/ +@!@:adj\_demerits\_}{\.{\\adjdemerits} primitive@> +primitive("mag", assign_int, int_base+mag_code);@/ +@!@:mag\_}{\.{\\mag} primitive@> +primitive("delimiterfactor", assign_int, int_base+delimiter_factor_code);@/ +@!@:delimiter\_factor\_}{\.{\\delimiterfactor} primitive@> +primitive("looseness", assign_int, int_base+looseness_code);@/ +@!@:looseness\_}{\.{\\looseness} primitive@> +primitive("time", assign_int, int_base+time_code);@/ +@!@:time\_}{\.{\\time} primitive@> +primitive("day", assign_int, int_base+day_code);@/ +@!@:day\_}{\.{\\day} primitive@> +primitive("month", assign_int, int_base+month_code);@/ +@!@:month\_}{\.{\\month} primitive@> +primitive("year", assign_int, int_base+year_code);@/ +@!@:year\_}{\.{\\year} primitive@> +primitive("showboxbreadth", assign_int, int_base+show_box_breadth_code);@/ +@!@:show\_box\_breadth\_}{\.{\\showboxbreadth} primitive@> +primitive("showboxdepth", assign_int, int_base+show_box_depth_code);@/ +@!@:show\_box\_depth\_}{\.{\\showboxdepth} primitive@> +primitive("hbadness", assign_int, int_base+hbadness_code);@/ +@!@:hbadness\_}{\.{\\hbadness} primitive@> +primitive("vbadness", assign_int, int_base+vbadness_code);@/ +@!@:vbadness\_}{\.{\\vbadness} primitive@> +primitive("pausing", assign_int, int_base+pausing_code);@/ +@!@:pausing\_}{\.{\\pausing} primitive@> +primitive("tracingonline", assign_int, int_base+tracing_online_code);@/ +@!@:tracing\_online\_}{\.{\\tracingonline} primitive@> +primitive("tracingmacros", assign_int, int_base+tracing_macros_code);@/ +@!@:tracing\_macros\_}{\.{\\tracingmacros} primitive@> +primitive("tracingstats", assign_int, int_base+tracing_stats_code);@/ +@!@:tracing\_stats\_}{\.{\\tracingstats} primitive@> +primitive("tracingparagraphs", assign_int, int_base+tracing_paragraphs_code);@/ +@!@:tracing\_paragraphs\_}{\.{\\tracingparagraphs} primitive@> +primitive("tracingpages", assign_int, int_base+tracing_pages_code);@/ +@!@:tracing\_pages\_}{\.{\\tracingpages} primitive@> +primitive("tracingoutput", assign_int, int_base+tracing_output_code);@/ +@!@:tracing\_output\_}{\.{\\tracingoutput} primitive@> +primitive("tracinglostchars", assign_int, int_base+tracing_lost_chars_code);@/ +@!@:tracing\_lost\_chars\_}{\.{\\tracinglostchars} primitive@> +primitive("tracingcommands", assign_int, int_base+tracing_commands_code);@/ +@!@:tracing\_commands\_}{\.{\\tracingcommands} primitive@> +primitive("tracingrestores", assign_int, int_base+tracing_restores_code);@/ +@!@:tracing\_restores\_}{\.{\\tracingrestores} primitive@> +primitive("uchyph", assign_int, int_base+uc_hyph_code);@/ +@!@:uc\_hyph\_}{\.{\\uchyph} primitive@> +primitive("outputpenalty", assign_int, int_base+output_penalty_code);@/ +@!@:output\_penalty\_}{\.{\\outputpenalty} primitive@> +primitive("maxdeadcycles", assign_int, int_base+max_dead_cycles_code);@/ +@!@:max\_dead\_cycles\_}{\.{\\maxdeadcycles} primitive@> +primitive("hangafter", assign_int, int_base+hang_after_code);@/ +@!@:hang\_after\_}{\.{\\hangafter} primitive@> +primitive("floatingpenalty", assign_int, int_base+floating_penalty_code);@/ +@!@:floating\_penalty\_}{\.{\\floatingpenalty} primitive@> +primitive("globaldefs", assign_int, int_base+global_defs_code);@/ +@!@:global\_defs\_}{\.{\\globaldefs} primitive@> +primitive("fam", assign_int, int_base+cur_fam_code);@/ +@!@:fam\_}{\.{\\fam} primitive@> +primitive("escapechar", assign_int, int_base+escape_char_code);@/ +@!@:escape\_char\_}{\.{\\escapechar} primitive@> +primitive("defaulthyphenchar", assign_int, int_base+default_hyphen_char_code);@/ +@!@:default\_hyphen\_char\_}{\.{\\defaulthyphenchar} primitive@> +primitive("defaultskewchar", assign_int, int_base+default_skew_char_code);@/ +@!@:default\_skew\_char\_}{\.{\\defaultskewchar} primitive@> +primitive("endlinechar", assign_int, int_base+end_line_char_code);@/ +@!@:end\_line\_char\_}{\.{\\endlinechar} primitive@> +primitive("newlinechar", assign_int, int_base+new_line_char_code);@/ +@!@:new\_line\_char\_}{\.{\\newlinechar} primitive@> +primitive("language", assign_int, int_base+language_code);@/ +@!@:language\_}{\.{\\language} primitive@> +primitive("lefthyphenmin", assign_int, int_base+left_hyphen_min_code);@/ +@!@:left\_hyphen\_min\_}{\.{\\lefthyphenmin} primitive@> +primitive("righthyphenmin", assign_int, int_base+right_hyphen_min_code);@/ +@!@:right\_hyphen\_min\_}{\.{\\righthyphenmin} primitive@> +primitive("holdinginserts", assign_int, int_base+holding_inserts_code);@/ +@!@:holding\_inserts\_}{\.{\\holdinginserts} primitive@> +primitive("errorcontextlines", assign_int, int_base+error_context_lines_code);@/ +@!@:error\_context\_lines\_}{\.{\\errorcontextlines} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case assign_int: if (chr_code < count_base) print_param(chr_code-int_base); + else{@+print_esc("count");print_int(chr_code-count_base); + } @+break; + +@ The integer parameters should really be initialized by a macro package; +the following initialization does the minimum to keep \TeX\ from +complete failure. +@^null delimiter@> + +@<Initialize table entries...@>= +for (k=int_base; k<=del_code_base-1; k++) eqtb[k].i=0; +mag=1000;tolerance=10000;hang_after=1;max_dead_cycles=25; +escape_char='\\';end_line_char=carriage_return; +for (k=0; k<=255; k++) del_code(k)=-1; +del_code('.')=0; /*this null delimiter is used in error recovery*/ + +@ The following procedure, which is called just before \TeX\ initializes its +input and output, establishes the initial values of the date and time. +@^system dependencies@> +k\TeX\ calls |tl_now| to obtain the current time as a |tm| structure. +@p static void fix_date_and_time(void) +{@+struct tm *gmt=tl_now(); + time= gmt->tm_hour*60+gmt->tm_min; + day= gmt->tm_mday; + month=gmt->tm_mon+1; + year=gmt->tm_year+1900; +} + +@ @<Show equivalent |n|, in region 5@>= +{@+if (n < count_base) print_param(n-int_base); +else if (n < del_code_base) + {@+print_esc("count");print_int(n-count_base); + } +else{@+print_esc("delcode");print_int(n-del_code_base); + } +print_char('=');print_int(eqtb[n].i); +} + +@ @<Set variable |c| to the current escape character@>=c=escape_char + +@ @<Character |s| is the current new-line character@>=s==new_line_char + +@ \TeX\ is occasionally supposed to print diagnostic information that +goes only into the transcript file, unless |tracing_online| is positive. +Here are two routines that adjust the destination of print commands: + +@p void begin_diagnostic(void) /*prepare to do some tracing*/ +{@+old_setting=selector; +if ((tracing_online <= 0)&&(selector==term_and_log)) + {@+decr(selector); + if (history==spotless) history=warning_issued; + } +} +@# +void end_diagnostic(bool @!blank_line) + /*restore proper conditions after tracing*/ +{@+print_nl(""); +if (blank_line) print_ln(); +selector=old_setting; +} + +@ Of course we had better declare another global variable, if the previous +routines are going to work. + +@<Glob...@>= +static int @!old_setting; + +@ The final region of |eqtb| contains the dimension parameters defined +here, and the 256 \.{\\dimen} registers. + +@d par_indent_code 0 /*indentation of paragraphs*/ +@d math_surround_code 1 /*space around math in text*/ +@d line_skip_limit_code 2 /*threshold for |line_skip| instead of |baseline_skip|*/ +@d hsize_code 3 /*line width in horizontal mode*/ +@d vsize_code 4 /*page height in vertical mode*/ +@d max_depth_code 5 /*maximum depth of boxes on main pages*/ +@d split_max_depth_code 6 /*maximum depth of boxes on split pages*/ +@d box_max_depth_code 7 /*maximum depth of explicit vboxes*/ +@d hfuzz_code 8 /*tolerance for overfull hbox messages*/ +@d vfuzz_code 9 /*tolerance for overfull vbox messages*/ +@d delimiter_shortfall_code 10 /*maximum amount uncovered by variable delimiters*/ +@d null_delimiter_space_code 11 /*blank space in null delimiters*/ +@d script_space_code 12 /*extra space after subscript or superscript*/ +@d pre_display_size_code 13 /*length of text preceding a display*/ +@d display_width_code 14 /*length of line for displayed equation*/ +@d display_indent_code 15 /*indentation of line for displayed equation*/ +@d overfull_rule_code 16 /*width of rule that identifies overfull hboxes*/ +@d hang_indent_code 17 /*amount of hanging indentation*/ +@d h_offset_code 18 /*amount of horizontal offset when shipping pages out*/ +@d v_offset_code 19 /*amount of vertical offset when shipping pages out*/ +@d emergency_stretch_code 20 /*reduces badnesses on final pass of line-breaking*/ +@d dimen_pars 21 /*total number of dimension parameters*/ +@d scaled_base (dimen_base+dimen_pars) + /*table of 256 user-defined \.{\\dimen} registers*/ +@d eqtb_size (scaled_base+255) /*largest subscript of |eqtb|*/ +@# +@d dimen(A) eqtb[scaled_base+A].sc +@d dimen_par(A) eqtb[dimen_base+A].sc /*a scaled quantity*/ +@d dimen_hfactor(A) hfactor_eqtb[scaled_base+A].sc +@d dimen_vfactor(A) vfactor_eqtb[scaled_base+A].sc +@d dimen_par_hfactor(A) hfactor_eqtb[dimen_base+A].sc +@d dimen_par_vfactor(A) vfactor_eqtb[dimen_base+A].sc +@d par_indent dimen_par(par_indent_code) +@d math_surround dimen_par(math_surround_code) +@d line_skip_limit dimen_par(line_skip_limit_code) +@d hsize dimen_par(hsize_code) +@d vsize dimen_par(vsize_code) +@d max_depth dimen_par(max_depth_code) +@d split_max_depth dimen_par(split_max_depth_code) +@d box_max_depth dimen_par(box_max_depth_code) +@d hfuzz dimen_par(hfuzz_code) +@d vfuzz dimen_par(vfuzz_code) +@d delimiter_shortfall dimen_par(delimiter_shortfall_code) +@d null_delimiter_space dimen_par(null_delimiter_space_code) +@d script_space dimen_par(script_space_code) +@d pre_display_size dimen_par(pre_display_size_code) +@d display_width dimen_par(display_width_code) +@d display_indent dimen_par(display_indent_code) +@d overfull_rule dimen_par(overfull_rule_code) +@d hang_indent dimen_par(hang_indent_code) +@d h_offset dimen_par(h_offset_code) +@d v_offset dimen_par(v_offset_code) +@d emergency_stretch dimen_par(emergency_stretch_code) + +@p static void print_length_param(int @!n) +{@+switch (n) { +case par_indent_code: print_esc("parindent");@+break; +case math_surround_code: print_esc("mathsurround");@+break; +case line_skip_limit_code: print_esc("lineskiplimit");@+break; +case hsize_code: print_esc("hsize");@+break; +case vsize_code: print_esc("vsize");@+break; +case max_depth_code: print_esc("maxdepth");@+break; +case split_max_depth_code: print_esc("splitmaxdepth");@+break; +case box_max_depth_code: print_esc("boxmaxdepth");@+break; +case hfuzz_code: print_esc("hfuzz");@+break; +case vfuzz_code: print_esc("vfuzz");@+break; +case delimiter_shortfall_code: print_esc("delimitershortfall");@+break; +case null_delimiter_space_code: print_esc("nulldelimiterspace");@+break; +case script_space_code: print_esc("scriptspace");@+break; +case pre_display_size_code: print_esc("predisplaysize");@+break; +case display_width_code: print_esc("displaywidth");@+break; +case display_indent_code: print_esc("displayindent");@+break; +case overfull_rule_code: print_esc("overfullrule");@+break; +case hang_indent_code: print_esc("hangindent");@+break; +case h_offset_code: print_esc("hoffset");@+break; +case v_offset_code: print_esc("voffset");@+break; +case emergency_stretch_code: print_esc("emergencystretch");@+break; +default:print("[unknown dimen parameter!]"); +} +} + +@ @<Put each...@>= +primitive("parindent", assign_dimen, dimen_base+par_indent_code);@/ +@!@:par\_indent\_}{\.{\\parindent} primitive@> +primitive("mathsurround", assign_dimen, dimen_base+math_surround_code);@/ +@!@:math\_surround\_}{\.{\\mathsurround} primitive@> +primitive("lineskiplimit", assign_dimen, dimen_base+line_skip_limit_code);@/ +@!@:line\_skip\_limit\_}{\.{\\lineskiplimit} primitive@> +primitive("hsize", assign_dimen, dimen_base+hsize_code);@/ +@!@:hsize\_}{\.{\\hsize} primitive@> +primitive("vsize", assign_dimen, dimen_base+vsize_code);@/ +@!@:vsize\_}{\.{\\vsize} primitive@> +primitive("maxdepth", assign_dimen, dimen_base+max_depth_code);@/ +@!@:max\_depth\_}{\.{\\maxdepth} primitive@> +primitive("splitmaxdepth", assign_dimen, dimen_base+split_max_depth_code);@/ +@!@:split\_max\_depth\_}{\.{\\splitmaxdepth} primitive@> +primitive("boxmaxdepth", assign_dimen, dimen_base+box_max_depth_code);@/ +@!@:box\_max\_depth\_}{\.{\\boxmaxdepth} primitive@> +primitive("hfuzz", assign_dimen, dimen_base+hfuzz_code);@/ +@!@:hfuzz\_}{\.{\\hfuzz} primitive@> +primitive("vfuzz", assign_dimen, dimen_base+vfuzz_code);@/ +@!@:vfuzz\_}{\.{\\vfuzz} primitive@> +primitive("delimitershortfall", + assign_dimen, dimen_base+delimiter_shortfall_code);@/ +@!@:delimiter\_shortfall\_}{\.{\\delimitershortfall} primitive@> +primitive("nulldelimiterspace", + assign_dimen, dimen_base+null_delimiter_space_code);@/ +@!@:null\_delimiter\_space\_}{\.{\\nulldelimiterspace} primitive@> +primitive("scriptspace", assign_dimen, dimen_base+script_space_code);@/ +@!@:script\_space\_}{\.{\\scriptspace} primitive@> +primitive("predisplaysize", assign_dimen, dimen_base+pre_display_size_code);@/ +@!@:pre\_display\_size\_}{\.{\\predisplaysize} primitive@> +primitive("displaywidth", assign_dimen, dimen_base+display_width_code);@/ +@!@:display\_width\_}{\.{\\displaywidth} primitive@> +primitive("displayindent", assign_dimen, dimen_base+display_indent_code);@/ +@!@:display\_indent\_}{\.{\\displayindent} primitive@> +primitive("overfullrule", assign_dimen, dimen_base+overfull_rule_code);@/ +@!@:overfull\_rule\_}{\.{\\overfullrule} primitive@> +primitive("hangindent", assign_dimen, dimen_base+hang_indent_code);@/ +@!@:hang\_indent\_}{\.{\\hangindent} primitive@> +primitive("hoffset", assign_dimen, dimen_base+h_offset_code);@/ +@!@:h\_offset\_}{\.{\\hoffset} primitive@> +primitive("voffset", assign_dimen, dimen_base+v_offset_code);@/ +@!@:v\_offset\_}{\.{\\voffset} primitive@> +primitive("emergencystretch", assign_dimen, dimen_base+emergency_stretch_code);@/ +@!@:emergency\_stretch\_}{\.{\\emergencystretch} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case assign_dimen: if (chr_code < scaled_base) + print_length_param(chr_code-dimen_base); + else{@+print_esc("dimen");print_int(chr_code-scaled_base); + } @+break; + +@ @<Initialize table entries...@>= +for (k=dimen_base; k<=eqtb_size; k++) hfactor_eqtb[k].sc=vfactor_eqtb[k].sc=eqtb[k].sc=0; + +@ @<Show equivalent |n|, in region 6@>= +{@+if (n < scaled_base) print_length_param(n-dimen_base); +else{@+print_esc("dimen");print_int(n-scaled_base); + } +print_char('=');print_scaled(eqtb[n].sc);print("pt"); +} + +@ Here is a procedure that displays the contents of |eqtb[n]| +symbolically. + +@p @t\4@>@<Declare the procedure called |print_cmd_chr|@>@;@/ +#ifdef @!STAT +static void show_eqtb(pointer @!n) +{@+if (n < active_base) print_char('?'); /*this can't happen*/ +else if (n < glue_base) @<Show equivalent |n|, in region 1 or 2@>@; +else if (n < local_base) @<Show equivalent |n|, in region 3@>@; +else if (n < int_base) @<Show equivalent |n|, in region 4@>@; +else if (n < dimen_base) @<Show equivalent |n|, in region 5@>@; +else if (n <= eqtb_size) @<Show equivalent |n|, in region 6@>@; +else print_char('?'); /*this can't happen either*/ +} +#endif + +@ The last two regions of |eqtb| have fullword values instead of the +three fields |eq_level|, |eq_type|, and |equiv|. An |eq_type| is unnecessary, +but \TeX\ needs to store the |eq_level| information in another array +called |xeq_level|. + +@<Glob...@>= +memory_word @!eqtb0[eqtb_size-active_base+1], *const @!eqtb = @!eqtb0-active_base; +memory_word hfactor_eqtb0[dimen_pars+256]={{{0}}}, *const @!hfactor_eqtb = @!hfactor_eqtb0-dimen_base; +memory_word vfactor_eqtb0[dimen_pars+256]={{{0}}}, *const @!vfactor_eqtb = @!vfactor_eqtb0-dimen_base; +scaled par_shape_hfactor=0, par_shape_vfactor=0; +scaled hhsize=0,hvsize=0; +static quarterword @!xeq_level0[eqtb_size-int_base+1], *const @!xeq_level = @!xeq_level0-int_base; + +@ @<Set init...@>= +for (k=int_base; k<=eqtb_size; k++) xeq_level[k]=level_one; + +@ When the debugging routine |search_mem| is looking for pointers having a +given value, it is interested only in regions 1 to~3 of~|eqtb|, and in the +first part of region~4. + +@<Search |eqtb| for equivalents equal to |p|@>= +for (q=active_base; q<=box_base+255; q++) + {@+if (equiv(q)==p) + {@+print_nl("EQUIV(");print_int(q);print_char(')'); + } + } + +@* The hash table. +Control sequences are stored and retrieved by means of a fairly standard hash +table algorithm called the method of ``coalescing lists'' (cf.\ Algorithm 6.4C +in {\sl The Art of Computer Programming\/}). Once a control sequence enters the +table, it is never removed, because there are complicated situations +involving \.{\\gdef} where the removal of a control sequence at the end of +a group would be a mistake preventable only by the introduction of a +complicated reference-count mechanism. + +The actual sequence of letters forming a control sequence identifier is +stored in the |str_pool| array together with all the other strings. An +auxiliary array |hash| consists of items with two halfword fields per +word. The first of these, called |next(p)|, points to the next identifier +belonging to the same coalesced list as the identifier corresponding to~|p|; +and the other, called |text(p)|, points to the |str_start| entry for +|p|'s identifier. If position~|p| of the hash table is empty, we have +|text(p)==0|; if position |p| is either empty or the end of a coalesced +hash list, we have |next(p)==0|. An auxiliary pointer variable called +|hash_used| is maintained in such a way that all locations |p >= hash_used| +are nonempty. The global variable |cs_count| tells how many multiletter +control sequences have been defined, if statistics are being kept. + +A global boolean variable called |no_new_control_sequence| is set to +|true| during the time that new hash table entries are forbidden. + +@d next(A) hash[A].lh /*link for coalesced lists*/ +@d text(A) hash[A].rh /*string number for control sequence name*/ +@d hash_is_full (hash_used==hash_base) /*test if all positions are occupied*/ +@d font_id_text(A) text(font_id_base+A) /*a frozen font identifier's name*/ + +@<Glob...@>= +two_halves @!hash0[undefined_control_sequence-hash_base], *const @!hash = @!hash0-hash_base; + /*the hash table*/ +static pointer @!hash_used; /*allocation pointer for |hash|*/ +static bool @!no_new_control_sequence; /*are new identifiers legal?*/ +static int @!cs_count; /*total number of known identifiers*/ + +@ @<Set init...@>= +no_new_control_sequence=true; /*new identifiers are usually forbidden*/ +next(hash_base)=0;text(hash_base)=0; +for (k=hash_base+1; k<=undefined_control_sequence-1; k++) hash[k]=hash[hash_base]; + +@ @<Initialize table entries...@>= +hash_used=frozen_control_sequence; /*nothing is used*/ +cs_count=0; +eq_type(frozen_dont_expand)=dont_expand; +text(frozen_dont_expand)=s_no("notexpanded:"); +@.notexpanded:@> + +@ Here is the subroutine that searches the hash table for an identifier +that matches a given string of length |l > 1| appearing in |buffer[j dotdot +(j+l-1)]|. If the identifier is found, the corresponding hash table address +is returned. Otherwise, if the global variable |no_new_control_sequence| +is |true|, the dummy address |undefined_control_sequence| is returned. +Otherwise the identifier is inserted into the hash table and its location +is returned. + +@p static pointer id_lookup(int @!j, int @!l) /*search the hash table*/ +{@+ /*go here if you found it*/ +int h; /*hash code*/ +int @!d; /*number of characters in incomplete current string*/ +pointer @!p; /*index in |hash| array*/ +int @!k; /*index in |buffer| array*/ +@<Compute the hash code |h|@>; +p=h+hash_base; /*we start searching here; note that |0 <= h < hash_prime|*/ +loop@+{@+if (text(p) > 0) if (length(text(p))==l) + if (str_eq_buf(text(p), j)) goto found; + if (next(p)==0) + {@+if (no_new_control_sequence) + p=undefined_control_sequence; + else@<Insert a new control sequence after |p|, then make |p| point to it@>; + goto found; + } + p=next(p); + } +found: return p; +} + +@ @<Insert a new control...@>= +{@+if (text(p) > 0) + {@+@/do@+{if (hash_is_full) overflow("hash size", hash_size); +@:TeX capacity exceeded hash size}{\quad hash size@> + decr(hash_used); + }@+ while (!(text(hash_used)==0)); /*search for an empty location in |hash|*/ + next(p)=hash_used;p=hash_used; + } +str_room(l);d=cur_length; +while (pool_ptr > str_start[str_ptr]) + {@+decr(pool_ptr);str_pool[pool_ptr+l]=str_pool[pool_ptr]; + } /*move current string up to make room for another*/ +for (k=j; k<=j+l-1; k++) append_char(buffer[k]); +text(p)=make_string();pool_ptr=pool_ptr+d; +#ifdef @!STAT +incr(cs_count); +#endif +@;@/ +} + +@ The value of |hash_prime| should be roughly 85\pct! of |hash_size|, and it +should be a prime number. The theory of hashing tells us to expect fewer +than two table probes, on the average, when the search is successful. +[See J.~S. Vitter, {\sl Journal of the ACM\/ \bf30} (1983), 231--258.] +@^Vitter, Jeffrey Scott@> + +@<Compute the hash code |h|@>= +h=buffer[j]; +for (k=j+1; k<=j+l-1; k++) + {@+h=h+h+buffer[k]; + while (h >= hash_prime) h=h-hash_prime; + } + +@ Single-character control sequences do not need to be looked up in a hash +table, since we can use the character code itself as a direct address. +The procedure |print_cs| prints the name of a control sequence, given +a pointer to its address in |eqtb|. A space is printed after the name +unless it is a single nonletter or an active character. This procedure +might be invoked with invalid data, so it is ``extra robust.'' The +individual characters must be printed one at a time using |print|, since +they may be unprintable. + +@<Basic printing...@>= +static void print_cs(int @!p) /*prints a purported control sequence*/ +{@+if (p < hash_base) /*single character*/ + if (p >= single_base) + if (p==null_cs) + {@+print_esc("csname");print_esc("endcsname");print_char(' '); + } + else{@+printn_esc(p-single_base); + if (cat_code(p-single_base)==letter) print_char(' '); + } + else if (p < active_base) print_esc("IMPOSSIBLE."); +@.IMPOSSIBLE@> + else printn(p-active_base); +else if (p >= undefined_control_sequence) print_esc("IMPOSSIBLE."); +else if ((text(p) < 0)||(text(p) >= str_ptr)) print_esc("NONEXISTENT."); +@.NONEXISTENT@> +else{@+printn_esc(text(p)); + print_char(' '); + } +} + +@ Here is a similar procedure; it avoids the error checks, and it never +prints a space after the control sequence. + +@<Basic printing procedures@>= +static void sprint_cs(pointer @!p) /*prints a control sequence*/ +{@+if (p < hash_base) + if (p < single_base) printn(p-active_base); + else if (p < null_cs) printn_esc(p-single_base); + else{@+print_esc("csname");print_esc("endcsname"); + } +else printn_esc(text(p)); +} + +@ We need to put \TeX's ``primitive'' control sequences into the hash +table, together with their command code (which will be the |eq_type|) +and an operand (which will be the |equiv|). The |primitive| procedure +does this, in a way that no \TeX\ user can. The global value |cur_val| +contains the new |eqtb| pointer after |primitive| has acted. + +@p +#ifdef @!INIT +static void primitive(char *@!str, quarterword @!c, halfword @!o) +{@+str_number s=s_no(str); +int k; /*index into |str_pool|*/ +int @!j; /*index into |buffer|*/ +small_number @!l; /*length of the string*/ +if (s < 256) cur_val=s+single_base; +else{@+k=str_start[s];l=str_start[s+1]-k; + /*we will move |s| into the (possibly non-empty) |buffer|*/ + if (first+l > buf_size+1) + overflow("buffer size", buf_size); +@:TeX capacity exceeded buffer size}{\quad buffer size@> + for (j=0; j<=l-1; j++) buffer[first+j]=so(str_pool[k+j]); + cur_val=id_lookup(first, l); /*|no_new_control_sequence| is |false|*/ + flush_string;text(cur_val)=s; /*we don't want to have the string twice*/ + } +eq_level(cur_val)=level_one;eq_type(cur_val)=c;equiv(cur_val)=o; +} +#endif + +@ Many of \TeX's primitives need no |equiv|, since they are identifiable +by their |eq_type| alone. These primitives are loaded into the hash table +as follows: + +@<Put each of \TeX's primitives into the hash table@>= +primitive(" ", ex_space, 0);@/ +@!@:Single-character primitives /}{\quad\.{\\\ }@> +primitive("/", ital_corr, 0);@/ +@!@:Single-character primitives /}{\quad\.{\\/}@> +primitive("accent", accent, 0);@/ +@!@:accent\_}{\.{\\accent} primitive@> +primitive("advance", advance, 0);@/ +@!@:advance\_}{\.{\\advance} primitive@> +primitive("afterassignment", after_assignment, 0);@/ +@!@:after\_assignment\_}{\.{\\afterassignment} primitive@> +primitive("aftergroup", after_group, 0);@/ +@!@:after\_group\_}{\.{\\aftergroup} primitive@> +primitive("begingroup", begin_group, 0);@/ +@!@:begin\_group\_}{\.{\\begingroup} primitive@> +primitive("char", char_num, 0);@/ +@!@:char\_}{\.{\\char} primitive@> +primitive("csname", cs_name, 0);@/ +@!@:cs\_name\_}{\.{\\csname} primitive@> +primitive("delimiter", delim_num, 0);@/ +@!@:delimiter\_}{\.{\\delimiter} primitive@> +primitive("divide", divide, 0);@/ +@!@:divide\_}{\.{\\divide} primitive@> +primitive("endcsname", end_cs_name, 0);@/ +@!@:end\_cs\_name\_}{\.{\\endcsname} primitive@> +primitive("endgroup", end_group, 0); +@!@:end\_group\_}{\.{\\endgroup} primitive@> +text(frozen_end_group)=text(cur_val);eqtb[frozen_end_group]=eqtb[cur_val];@/ +primitive("expandafter", expand_after, 0);@/ +@!@:expand\_after\_}{\.{\\expandafter} primitive@> +primitive("font", def_font, 0);@/ +@!@:font\_}{\.{\\font} primitive@> +primitive("fontdimen", assign_font_dimen, 0);@/ +@!@:font\_dimen\_}{\.{\\fontdimen} primitive@> +primitive("halign", halign, 0);@/ +@!@:halign\_}{\.{\\halign} primitive@> +primitive("hrule", hrule, 0);@/ +@!@:hrule\_}{\.{\\hrule} primitive@> +primitive("ignorespaces", ignore_spaces, 0);@/ +@!@:ignore\_spaces\_}{\.{\\ignorespaces} primitive@> +primitive("insert", insert, 0);@/ +@!@:insert\_}{\.{\\insert} primitive@> +primitive("mark", mark, 0);@/ +@!@:mark\_}{\.{\\mark} primitive@> +primitive("mathaccent", math_accent, 0);@/ +@!@:math\_accent\_}{\.{\\mathaccent} primitive@> +primitive("mathchar", math_char_num, 0);@/ +@!@:math\_char\_}{\.{\\mathchar} primitive@> +primitive("mathchoice", math_choice, 0);@/ +@!@:math\_choice\_}{\.{\\mathchoice} primitive@> +primitive("multiply", multiply, 0);@/ +@!@:multiply\_}{\.{\\multiply} primitive@> +primitive("noalign", no_align, 0);@/ +@!@:no\_align\_}{\.{\\noalign} primitive@> +primitive("noboundary", no_boundary, 0);@/ +@!@:no\_boundary\_}{\.{\\noboundary} primitive@> +primitive("noexpand", no_expand, 0);@/ +@!@:no\_expand\_}{\.{\\noexpand} primitive@> +primitive("nonscript", non_script, 0);@/ +@!@:non\_script\_}{\.{\\nonscript} primitive@> +primitive("omit", omit, 0);@/ +@!@:omit\_}{\.{\\omit} primitive@> +primitive("parshape", set_shape, par_shape_loc);@/ +@!@:par\_shape\_}{\.{\\parshape} primitive@> +primitive("penalty", break_penalty, 0);@/ +@!@:penalty\_}{\.{\\penalty} primitive@> +primitive("prevgraf", set_prev_graf, 0);@/ +@!@:prev\_graf\_}{\.{\\prevgraf} primitive@> +primitive("radical", radical, 0);@/ +@!@:radical\_}{\.{\\radical} primitive@> +primitive("read", read_to_cs, 0);@/ +@!@:read\_}{\.{\\read} primitive@> +primitive("relax", relax, 256); /*cf.\ |scan_file_name|*/ +@!@:relax\_}{\.{\\relax} primitive@> +text(frozen_relax)=text(cur_val);eqtb[frozen_relax]=eqtb[cur_val];@/ +primitive("setbox", set_box, 0);@/ +@!@:set\_box\_}{\.{\\setbox} primitive@> +primitive("the", the, 0);@/ +@!@:the\_}{\.{\\the} primitive@> +primitive("toks", toks_register, mem_bot);@/ +@!@:toks\_}{\.{\\toks} primitive@> +primitive("vadjust", vadjust, 0);@/ +@!@:vadjust\_}{\.{\\vadjust} primitive@> +primitive("valign", valign, 0);@/ +@!@:valign\_}{\.{\\valign} primitive@> +primitive("vcenter", vcenter, 0);@/ +@!@:vcenter\_}{\.{\\vcenter} primitive@> +primitive("vrule", vrule, 0);@/ +@!@:vrule\_}{\.{\\vrule} primitive@> + +@ Each primitive has a corresponding inverse, so that it is possible to +display the cryptic numeric contents of |eqtb| in symbolic form. +Every call of |primitive| in this program is therefore accompanied by some +straightforward code that forms part of the |print_cmd_chr| routine +below. + +@<Cases of |print_cmd_chr|...@>= +case accent: print_esc("accent");@+break; +case advance: print_esc("advance");@+break; +case after_assignment: print_esc("afterassignment");@+break; +case after_group: print_esc("aftergroup");@+break; +case assign_font_dimen: print_esc("fontdimen");@+break; +case begin_group: print_esc("begingroup");@+break; +case break_penalty: print_esc("penalty");@+break; +case char_num: print_esc("char");@+break; +case cs_name: print_esc("csname");@+break; +case def_font: print_esc("font");@+break; +case delim_num: print_esc("delimiter");@+break; +case divide: print_esc("divide");@+break; +case end_cs_name: print_esc("endcsname");@+break; +case end_group: print_esc("endgroup");@+break; +case ex_space: print_esc(" ");@+break; +case expand_after: if (chr_code==0) print_esc("expandafter") + @<Cases of |expandafter| for |print_cmd_chr|@>;@+break; +case halign: print_esc("halign");@+break; +case hrule: print_esc("hrule");@+break; +case ignore_spaces: print_esc("ignorespaces");@+break; +case insert: print_esc("insert");@+break; +case ital_corr: print_esc("/");@+break; +case mark: print_esc("mark");@+break; +case math_accent: print_esc("mathaccent");@+break; +case math_char_num: print_esc("mathchar");@+break; +case math_choice: print_esc("mathchoice");@+break; +case multiply: print_esc("multiply");@+break; +case no_align: print_esc("noalign");@+break; +case no_boundary: print_esc("noboundary");@+break; +case no_expand: print_esc("noexpand");@+break; +case non_script: print_esc("nonscript");@+break; +case omit: print_esc("omit");@+break; +case radical: print_esc("radical");@+break; +case read_to_cs: if (chr_code==0) print_esc("read") + @<Cases of |read| for |print_cmd_chr|@>;@+break; +case relax: print_esc("relax");@+break; +case set_box: print_esc("setbox");@+break; +case set_prev_graf: print_esc("prevgraf");@+break; +case set_shape: switch (chr_code) { + case par_shape_loc: print_esc("parshape");@+break; + @<Cases of |set_shape| for |print_cmd_chr|@>@;@/ + } @+break; /*there are no other cases*/ +case the: if (chr_code==0) print_esc("the") + @<Cases of |the| for |print_cmd_chr|@>;@+break; +case toks_register: @<Cases of |toks_register| for |print_cmd_chr|@>@;@+break; +case vadjust: print_esc("vadjust");@+break; +case valign: print_esc("valign");@+break; +case vcenter: print_esc("vcenter");@+break; +case vrule: print_esc("vrule");@+break; + +@ We will deal with the other primitives later, at some point in the program +where their |eq_type| and |equiv| values are more meaningful. For example, +the primitives for math mode will be loaded when we consider the routines +that deal with formulas. It is easy to find where each particular +primitive was treated by looking in the index at the end; for example, the +section where |"radical"| entered |eqtb| is listed under `\.{\\radical} +primitive'. (Primitives consisting of a single nonalphabetic character, +@!like `\.{\\/}', are listed under `Single-character primitives'.) +@!@^Single-character primitives@> + +Meanwhile, this is a convenient place to catch up on something we were unable +to do before the hash table was defined: + +@<Print the font identifier for |font(p)|@>= +printn_esc(font_id_text(font(p))) + +@* Saving and restoring equivalents. +The nested structure provided by `$\.{\char'173}\ldots\.{\char'175}$' groups +in \TeX\ means that |eqtb| entries valid in outer groups should be saved +and restored later if they are overridden inside the braces. When a new |eqtb| +value is being assigned, the program therefore checks to see if the previous +entry belongs to an outer level. In such a case, the old value is placed +on the |save_stack| just before the new value enters |eqtb|. At the +end of a grouping level, i.e., when the right brace is sensed, the +|save_stack| is used to restore the outer values, and the inner ones are +destroyed. + +Entries on the |save_stack| are of type |memory_word|. The top item on +this stack is |save_stack[p]|, where |p==save_ptr-1|; it contains three +fields called |save_type|, |save_level|, and |save_index|, and it is +interpreted in one of five ways: + +\yskip\hangg 1) If |save_type(p)==restore_old_value|, then +|save_index(p)| is a location in |eqtb| whose current value should +be destroyed at the end of the current group and replaced by |save_stack[p-1]|. +Furthermore if |save_index(p) >= int_base|, then |save_level(p)| +should replace the corresponding entry in |xeq_level|. + +\yskip\hangg 2) If |save_type(p)==restore_zero|, then |save_index(p)| +is a location in |eqtb| whose current value should be destroyed at the end +of the current group, when it should be +replaced by the current value of |eqtb[undefined_control_sequence]|. + +\yskip\hangg 3) If |save_type(p)==insert_token|, then |save_index(p)| +is a token that should be inserted into \TeX's input when the current +group ends. + +\yskip\hangg 4) If |save_type(p)==level_boundary|, then |save_level(p)| +is a code explaining what kind of group we were previously in, and +|save_index(p)| points to the level boundary word at the bottom of +the entries for that group. +Furthermore, in extended \eTeX\ mode, |save_stack[p-1]| contains the +source line number at which the current level of grouping was entered. + +\yskip\hang 5) If |save_type(p)==restore_sa|, then |sa_chain| points to a +chain of sparse array entries to be restored at the end of the current +group. Furthermore |save_index(p)| and |save_level(p)| should replace +the values of |sa_chain| and |sa_level| respectively. + +@d save_type(A) save_stack[A].hh.b0 /*classifies a |save_stack| entry*/ +@d save_level(A) save_stack[A].hh.b1 + /*saved level for regions 5 and 6, or group code*/ +@d save_index(A) save_stack[A].hh.rh + /*|eqtb| location or token or |save_stack| location*/ +@d restore_old_value 0 /*|save_type| when a value should be restored later*/ +@d restore_zero 1 /*|save_type| when an undefined entry should be restored*/ +@d insert_token 2 /*|save_type| when a token is being saved for later use*/ +@d level_boundary 3 /*|save_type| corresponding to beginning of group*/ +@d restore_sa 4 /*|save_type| when sparse array entries should be restored*/ + +@p @t\4@>@<Declare \eTeX\ procedures for tracing and input@>@; + +@ Here are the group codes that are used to discriminate between different +kinds of groups. They allow \TeX\ to decide what special actions, if any, +should be performed when a group ends. +\def\grp{\.{\char'173...\char'175}} + +Some groups are not supposed to be ended by right braces. For example, +the `\.\$' that begins a math formula causes a |math_shift_group| to +be started, and this should be terminated by a matching `\.\$'. Similarly, +a group that starts with \.{\\left} should end with \.{\\right}, and +one that starts with \.{\\begingroup} should end with \.{\\endgroup}. + +@d bottom_level 0 /*group code for the outside world*/ +@d simple_group 1 /*group code for local structure only*/ +@d hbox_group 2 /*code for `\.{\\hbox}\grp'*/ +@d adjusted_hbox_group 3 /*code for `\.{\\hbox}\grp' in vertical mode*/ +@d vbox_group 4 /*code for `\.{\\vbox}\grp'*/ +@d vtop_group 5 /*code for `\.{\\vtop}\grp'*/ +@d align_group 6 /*code for `\.{\\halign}\grp', `\.{\\valign}\grp'*/ +@d no_align_group 7 /*code for `\.{\\noalign}\grp'*/ +@d output_group 8 /*code for output routine*/ +@d math_group 9 /*code for, e.g., `\.{\char'136}\grp'*/ +@d disc_group 10 /*code for `\.{\\discretionary}\grp\grp\grp'*/ +@d insert_group 11 /*code for `\.{\\insert}\grp', `\.{\\vadjust}\grp'*/ +@d vcenter_group 12 /*code for `\.{\\vcenter}\grp'*/ +@d math_choice_group 13 /*code for `\.{\\mathchoice}\grp\grp\grp\grp'*/ +@d semi_simple_group 14 /*code for `\.{\\begingroup...\\endgroup}'*/ +@d math_shift_group 15 /*code for `\.{\$...\$}'*/ +@d math_left_group 16 /*code for `\.{\\left...\\right}'*/ +@d page_group 17 +@d stream_group 18 +@d stream_before_group 19 +@d stream_after_group 20 +@d outline_group 21 +@d max_group_code 21 + +@<Types...@>= +typedef int8_t group_code; /*|save_level| for a level boundary*/ + +@ The global variable |cur_group| keeps track of what sort of group we are +currently in. Another global variable, |cur_boundary|, points to the +topmost |level_boundary| word. And |cur_level| is the current depth of +nesting. The routines are designed to preserve the condition that no entry +in the |save_stack| or in |eqtb| ever has a level greater than |cur_level|. + +@ @<Glob...@>= +static memory_word @!save_stack[save_size+1]; +static memory_word @!save_hfactor[save_size+1]; +static memory_word @!save_vfactor[save_size+1]; +static int @!save_ptr; /*first unused entry on |save_stack|*/ +static int @!max_save_stack; /*maximum usage of save stack*/ +static quarterword @!cur_level; /*current nesting level for groups*/ +static group_code @!cur_group; /*current group type*/ +static int @!cur_boundary; /*where the current level begins*/ + +@ At this time it might be a good idea for the reader to review the introduction +to |eqtb| that was given above just before the long lists of parameter names. +Recall that the ``outer level'' of the program is |level_one|, since +undefined control sequences are assumed to be ``defined'' at |level_zero|. + +@<Set init...@>= +save_ptr=0;cur_level=level_one;cur_group=bottom_level;cur_boundary=0; +max_save_stack=0; + +@ The following macro is used to test if there is room for up to seven more +entries on |save_stack|. By making a conservative test like this, we can +get by with testing for overflow in only a few places. + +@d check_full_save_stack if (save_ptr > max_save_stack) + {@+max_save_stack=save_ptr; + if (max_save_stack > save_size-7) overflow("save size", save_size); +@:TeX capacity exceeded save size}{\quad save size@> + } + +@ Procedure |new_save_level| is called when a group begins. The +argument is a group identification code like `|hbox_group|'. After +calling this routine, it is safe to put five more entries on |save_stack|. + +In some cases integer-valued items are placed onto the +|save_stack| just below a |level_boundary| word, because this is a +convenient place to keep information that is supposed to ``pop up'' just +when the group has finished. +For example, when `\.{\\hbox to 100pt}\grp' is being treated, the 100pt +dimension is stored on |save_stack| just before |new_save_level| is +called. + +We use the notation |saved(k)| to stand for an integer item that +appears in location |save_ptr+k| of the save stack. + +@d saved(A) save_stack[save_ptr+A].i +@d saved_hfactor(A) save_hfactor[save_ptr+A].i +@d saved_vfactor(A) save_vfactor[save_ptr+A].i + +@p void new_save_level(group_code @!c) /*begin a new level of grouping*/ +{@+check_full_save_stack; +if (eTeX_ex) + {@+saved(0)=line;incr(save_ptr); + } +save_type(save_ptr)=level_boundary;save_level(save_ptr)=cur_group; +save_index(save_ptr)=cur_boundary; +if (cur_level==max_quarterword) overflow("grouping levels", +@:TeX capacity exceeded grouping levels}{\quad grouping levels@> + max_quarterword-min_quarterword); + /*quit if |(cur_level+1)| is too big to be stored in |eqtb|*/ +cur_boundary=save_ptr;cur_group=c; +#ifdef @!STAT +if (tracing_groups > 0) group_trace(false); +#endif +@;@/ +incr(cur_level);incr(save_ptr); +} + +@ Just before an entry of |eqtb| is changed, the following procedure should +be called to update the other data structures properly. It is important +to keep in mind that reference counts in |mem| include references from +within |save_stack|, so these counts must be handled carefully. +@^reference counts@> + +@p static void eq_destroy(memory_word @!w) /*gets ready to forget |w|*/ +{@+pointer q; /*|equiv| field of |w|*/ +switch (eq_type_field(w)) { +case call: case long_call: case outer_call: case long_outer_call: delete_token_ref(equiv_field(w));@+break; +case glue_ref: delete_glue_ref(equiv_field(w));@+break; +case shape_ref: {@+q=equiv_field(w); /*we need to free a \.{\\parshape} block*/ + if (q!=null) free_node(q, info(q)+info(q)+1); + } @+break; /*such a block is |2 n+1| words long, where |n==info(q)|*/ +case box_ref: flush_node_list(equiv_field(w));@+break; +@/@<Cases for |eq_destroy|@>@/ +default:do_nothing; +} +} + +@ To save a value of |eqtb[p]| that was established at level |l|, we +can use the following subroutine. + +@p static void eq_save(pointer @!p, quarterword @!l) /*saves |eqtb[p]|*/ +{@+check_full_save_stack; +if (l==level_zero) save_type(save_ptr)=restore_zero; +else{@+save_stack[save_ptr]=eqtb[p]; + if (p>=dimen_base) + { save_hfactor[save_ptr]=hfactor_eqtb[p]; + save_vfactor[save_ptr]=vfactor_eqtb[p]; + } + else if (p==par_shape_loc) + { save_hfactor[save_ptr].i=par_shape_hfactor; + save_vfactor[save_ptr].i=par_shape_vfactor; + } + incr(save_ptr); + save_type(save_ptr)=restore_old_value; + } +save_level(save_ptr)=l;save_index(save_ptr)=p;incr(save_ptr); +} + +@ The procedure |eq_define| defines an |eqtb| entry having specified +|eq_type| and |equiv| fields, and saves the former value if appropriate. +This procedure is used only for entries in the first four regions of |eqtb|, +i.e., only for entries that have |eq_type| and |equiv| fields. +After calling this routine, it is safe to put four more entries on +|save_stack|, provided that there was room for four more entries before +the call, since |eq_save| makes the necessary test. + +@p +#ifdef @!STAT +#define assign_trace(A, B) if (tracing_assigns > 0) restore_trace(A, B); +#else +#define assign_trace(A, B) +#endif + +static void eq_define(pointer @!p, quarterword @!t, halfword @!e) + /*new data for |eqtb|*/ +{@+ +if (eTeX_ex&&(eq_type(p)==t)&&(equiv(p)==e)) + {@+assign_trace(p,"reassigning")@;@/ + eq_destroy(eqtb[p]);return; + } +assign_trace(p,"changing")@;@/ +if (eq_level(p)==cur_level) eq_destroy(eqtb[p]); +else if (cur_level > level_one) eq_save(p, eq_level(p)); +eq_level(p)=cur_level;eq_type(p)=t;equiv(p)=e; +if (p==par_shape_loc) +{ par_shape_hfactor=cur_hfactor; + par_shape_vfactor=cur_vfactor; +} +assign_trace(p,"into")@;@/ +} + +@ The counterpart of |eq_define| for the remaining (fullword) positions in +|eqtb| is called |eq_word_define|. Since |xeq_level[p] >= level_one| for all +|p|, a `|restore_zero|' will never be used in this case. + +@p static void eq_word_define(pointer @!p, int @!w) +{@+if (cur_level==level_one)@t\1@> + { if (p==dimen_base+hsize_code) + { hhsize=w+round(((double)cur_hfactor*hhsize +(double)cur_vfactor*hvsize)/unity); return; @+} + if (p==dimen_base+vsize_code) + { hvsize=w+round(((double)cur_hfactor*hhsize +(double)cur_vfactor*hvsize)/unity); return; @+} + } + if (xeq_level[p]!=cur_level) + {@+eq_save(p, xeq_level[p]);xeq_level[p]=cur_level; + } +eqtb[p].i=w; +if (p>=dimen_base) +{ hfactor_eqtb[p].i=cur_hfactor; + vfactor_eqtb[p].i=cur_vfactor; +} +assign_trace(p,"into")@;@/ +} + +@ The |eq_define| and |eq_word_define| routines take care of local definitions. +@^global definitions@> +Global definitions are done in almost the same way, but there is no need +to save old values, and the new value is associated with |level_one|. + +@p static void geq_define(pointer @!p, quarterword @!t, halfword @!e) + /*global |eq_define|*/ +{@+assign_trace(p,"globally changing")@;@/ +{@+eq_destroy(eqtb[p]); +eq_level(p)=level_one;eq_type(p)=t;equiv(p)=e; +} +assign_trace(p,"into");@/ +} +@# +static void geq_word_define(pointer @!p, int @!w) /*global |eq_word_define|*/ +{@+assign_trace(p,"globally changing")@;@/ +{@t\1@>xeq_level[p]=level_one; + if (p==dimen_base+hsize_code) + hhsize=w+round(((double)cur_hfactor*hhsize +(double)cur_vfactor*hvsize)/unity); + else if (p==dimen_base+vsize_code) + hvsize=w+round(((double)cur_hfactor*hhsize +(double)cur_vfactor*hvsize)/unity); + else + { eqtb[p].i=w; + if (p>=dimen_base) + { hfactor_eqtb[p].i=cur_hfactor; + vfactor_eqtb[p].i=cur_vfactor; + } +} +} +assign_trace(p,"into");@/ +} + +@ Subroutine |save_for_after| puts a token on the stack for save-keeping. + +@p static void save_for_after(halfword @!t) +{@+if (cur_level > level_one) + {@+check_full_save_stack; + save_type(save_ptr)=insert_token;save_level(save_ptr)=level_zero; + save_index(save_ptr)=t;incr(save_ptr); + } +} + +@ The |unsave| routine goes the other way, taking items off of |save_stack|. +This routine takes care of restoration when a level ends; everything +belonging to the topmost group is cleared off of the save stack. + +@p +static void back_input(void); +void unsave(void) /*pops the top level off the save stack*/ +{@+ +pointer p; /*position to be restored*/ +quarterword @!l; /*saved level, if in fullword regions of |eqtb|*/ +halfword @!t; /*saved value of |cur_tok|*/ +bool @!a; /*have we already processed an \.{\\aftergroup} ?*/ +a=false; +if (cur_level > level_one) + {@+decr(cur_level); + @<Clear off top level from |save_stack|@>; + } +else confusion("curlevel"); /*|unsave| is not used when |cur_group==bottom_level|*/ +@:this can't happen curlevel}{\quad curlevel@> +} + +@ @<Clear off...@>= +loop@+{@+decr(save_ptr); + if (save_type(save_ptr)==level_boundary) goto done; + p=save_index(save_ptr); + if (save_type(save_ptr)==insert_token) + @<Insert token |p| into \TeX's input@>@; + else if (save_type(save_ptr)==restore_sa) + {@+sa_restore();sa_chain=p;sa_level=save_level(save_ptr); + } + else{@+if (save_type(save_ptr)==restore_old_value) + {@+l=save_level(save_ptr);decr(save_ptr); + } + else save_stack[save_ptr]=eqtb[undefined_control_sequence]; + @<Store \(s)|save_stack[save_ptr]| in |eqtb[p]|, unless |eqtb[p]| holds a global +value@>; + } + } +done: +#ifdef @!STAT +if (tracing_groups > 0) group_trace(true); +#endif +@;@/ +if (grp_stack[in_open]==cur_boundary) group_warning(); + /*groups possibly not properly nested with files*/ +cur_group=save_level(save_ptr);cur_boundary=save_index(save_ptr); +if (eTeX_ex) decr(save_ptr) + +@ A global definition, which sets the level to |level_one|, +@^global definitions@> +will not be undone by |unsave|. If at least one global definition of +|eqtb[p]| has been carried out within the group that just ended, the +last such definition will therefore survive. + +@<Store \(s)|save...@>= +if (p < int_base) + if (eq_level(p)==level_one) + {@+eq_destroy(save_stack[save_ptr]); /*destroy the saved value*/ +#ifdef @!STAT + if (tracing_restores > 0) restore_trace(p,"retaining"); +#endif +@;@/ + } + else{@+eq_destroy(eqtb[p]); /*destroy the current value*/ + eqtb[p]=save_stack[save_ptr]; /*restore the saved value*/ + if (p==par_shape_loc) + { par_shape_hfactor=save_hfactor[save_ptr].i; + par_shape_vfactor=save_vfactor[save_ptr].i; + } +#ifdef @!STAT + if (tracing_restores > 0) restore_trace(p,"restoring"); +#endif +@;@/ + } +else if (xeq_level[p]!=level_one) + {@t\1@>@+eqtb[p]=save_stack[save_ptr]; + if (p>=dimen_base) + { hfactor_eqtb[p]=save_hfactor[save_ptr]; + vfactor_eqtb[p]=save_vfactor[save_ptr]; + } + xeq_level[p]=l; +#ifdef @!STAT + if (tracing_restores > 0) restore_trace(p,"restoring"); +#endif +@;@/ + } +else{ +#ifdef @!STAT + if (tracing_restores > 0) restore_trace(p,"retaining"); +#endif +@;@/ + } + +@ @<Declare \eTeX\ procedures for tr...@>= +#ifdef @!STAT +static void restore_trace(pointer @!p, char *@!s) + /*|eqtb[p]| has just been restored or retained*/ +{@+begin_diagnostic();print_char('{');print(s);print_char(' '); +show_eqtb(p);print_char('}'); +end_diagnostic(false); +} +#endif + +@ When looking for possible pointers to a memory location, it is helpful +to look for references from |eqtb| that might be waiting on the +save stack. Of course, we might find spurious pointers too; but this +routine is merely an aid when debugging, and at such times we are +grateful for any scraps of information, even if they prove to be irrelevant. +@^dirty \PASCAL@> + +@<Search |save_stack| for equivalents that point to |p|@>= +if (save_ptr > 0) for (q=0; q<=save_ptr-1; q++) + {@+if (equiv_field(save_stack[q])==p) + {@+print_nl("SAVE(");print_int(q);print_char(')'); + } + } + +@ Most of the parameters kept in |eqtb| can be changed freely, but there's +an exception: The magnification should not be used with two different +values during any \TeX\ job, since a single magnification is applied to an +entire run. The global variable |mag_set| is set to the current magnification +whenever it becomes necessary to ``freeze'' it at a particular value. + +@<Glob...@>= +static int @!mag_set; /*if nonzero, this magnification should be used henceforth*/ + +@ @<Set init...@>= +mag_set=0; + +@ The |prepare_mag| subroutine is called whenever \TeX\ wants to use |mag| +for magnification. + +@p static void prepare_mag(void) +{@+if ((mag_set > 0)&&(mag!=mag_set)) + {@+print_err("Incompatible magnification (");print_int(mag); +@.Incompatible magnification@> + print(");");print_nl(" the previous value will be retained"); + help2("I can handle only one magnification ratio per job. So I've",@/ + "reverted to the magnification you used earlier on this run.");@/ + int_error(mag_set); + geq_word_define(int_base+mag_code, mag_set); /*|mag=mag_set|*/ + } +if ((mag <= 0)||(mag > 32768)) + {@+print_err("Illegal magnification has been changed to 1000");@/ +@.Illegal magnification...@> + help1("The magnification ratio must be between 1 and 32768."); + int_error(mag);geq_word_define(int_base+mag_code, 1000); + } +mag_set=mag; +} + +@* Token lists. +A \TeX\ token is either a character or a control sequence, and it is +@^token@> +represented internally in one of two ways: (1)~A character whose ASCII +code number is |c| and whose command code is |m| is represented as the +number $2^8m+c$; the command code is in the range |1 <= m <= 14|. (2)~A control +sequence whose |eqtb| address is |p| is represented as the number +|cs_token_flag+p|. Here |cs_token_flag==@t$2^{12}-1$@>| is larger than +$2^8m+c$, yet it is small enough that |cs_token_flag+p < max_halfword|; +thus, a token fits comfortably in a halfword. + +A token |t| represents a |left_brace| command if and only if +|t < left_brace_limit|; it represents a |right_brace| command if and only if +we have |left_brace_limit <= t < right_brace_limit|; and it represents a |match| or +|end_match| command if and only if |match_token <= t <= end_match_token|. +The following definitions take care of these token-oriented constants +and a few others. + +@d cs_token_flag 07777 /*amount added to the |eqtb| location in a + token that stands for a control sequence; is a multiple of~256, less~1*/ +@d left_brace_token 00400 /*$2^8\cdot|left_brace|$*/ +@d left_brace_limit 01000 /*$2^8\cdot(|left_brace|+1)$*/ +@d right_brace_token 01000 /*$2^8\cdot|right_brace|$*/ +@d right_brace_limit 01400 /*$2^8\cdot(|right_brace|+1)$*/ +@d math_shift_token 01400 /*$2^8\cdot|math_shift|$*/ +@d tab_token 02000 /*$2^8\cdot|tab_mark|$*/ +@d out_param_token 02400 /*$2^8\cdot|out_param|$*/ +@d space_token 05040 /*$2^8\cdot|spacer|+|' '|$*/ +@d letter_token 05400 /*$2^8\cdot|letter|$*/ +@d other_token 06000 /*$2^8\cdot|other_char|$*/ +@d match_token 06400 /*$2^8\cdot|match|$*/ +@d end_match_token 07000 /*$2^8\cdot|end_match|$*/ +@d protected_token 07001 /*$2^8\cdot|end_match|+1$*/ + +@ @<Check the ``constant''...@>= +if (cs_token_flag+undefined_control_sequence > max_halfword) bad=21; + +@ A token list is a singly linked list of one-word nodes in |mem|, where +each word contains a token and a link. Macro definitions, output-routine +definitions, marks, \.{\\write} texts, and a few other things +are remembered by \TeX\ in the form +of token lists, usually preceded by a node with a reference count in its +|token_ref_count| field. The token stored in location |p| is called +|info(p)|. + +Three special commands appear in the token lists of macro definitions. +When |m==match|, it means that \TeX\ should scan a parameter +for the current macro; when |m==end_match|, it means that parameter +matching should end and \TeX\ should start reading the macro text; and +when |m==out_param|, it means that \TeX\ should insert parameter +number |c| into the text at this point. + +The enclosing \.{\char'173} and \.{\char'175} characters of a macro +definition are omitted, but the final right brace of an output routine +is included at the end of its token list. + +Here is an example macro definition that illustrates these conventions. +After \TeX\ processes the text +$$\.{\\def\\mac a\#1\#2 \\b \{\#1\\-a \#\#1\#2 \#2\}}$$ +the definition of \.{\\mac} is represented as a token list containing +$$\def\,{\hskip2pt} +\vbox{\halign{\hfil#\hfil\cr +(reference count), |letter|\,\.a, |match|\,\#, |match|\,\#, |spacer|\,\.\ , +\.{\\b}, |end_match|,\cr +|out_param|\,1, \.{\\-}, |letter|\,\.a, |spacer|\,\.\ , |mac_param|\,\#, +|other_char|\,\.1,\cr +|out_param|\,2, |spacer|\,\.\ , |out_param|\,2.\cr}}$$ +The procedure |scan_toks| builds such token lists, and |macro_call| +does the parameter matching. +@^reference counts@> + +Examples such as +$$\.{\\def\\m\{\\def\\m\{a\}\ b\}}$$ +explain why reference counts would be needed even if \TeX\ had no \.{\\let} +operation: When the token list for \.{\\m} is being read, the redefinition of +\.{\\m} changes the |eqtb| entry before the token list has been fully +consumed, so we dare not simply destroy a token list when its +control sequence is being redefined. + +If the parameter-matching part of a definition ends with `\.{\#\{}', +the corresponding token list will have `\.\{' just before the `|end_match|' +and also at the very end. The first `\.\{' is used to delimit the parameter; the +second one keeps the first from disappearing. + +@ The procedure |show_token_list|, which prints a symbolic form of +the token list that starts at a given node |p|, illustrates these +conventions. The token list being displayed should not begin with a reference +count. However, the procedure is intended to be robust, so that if the +memory links are awry or if |p| is not really a pointer to a token list, +nothing catastrophic will happen. + +An additional parameter |q| is also given; this parameter is either null +or it points to a node in the token list where a certain magic computation +takes place that will be explained later. (Basically, |q| is non-null when +we are printing the two-line context information at the time of an error +message; |q| marks the place corresponding to where the second line +should begin.) + +For example, if |p| points to the node containing the first \.a in the +token list above, then |show_token_list| will print the string +$$\hbox{`\.{a\#1\#2\ \\b\ ->\#1\\-a\ \#\#1\#2\ \#2}';}$$ +and if |q| points to the node containing the second \.a, +the magic computation will be performed just before the second \.a is printed. + +The generation will stop, and `\.{\\ETC.}' will be printed, if the length +of printing exceeds a given limit~|l|. Anomalous entries are printed in the +form of control sequences that are not followed by a blank space, e.g., +`\.{\\BAD.}'; this cannot be confused with actual control sequences because +a real control sequence named \.{BAD} would come out `\.{\\BAD\ }'. + +@<Declare the procedure called |show_token_list|@>= +static void show_token_list(int @!p, int @!q, int @!l) +{@+ +int m, @!c; /*pieces of a token*/ +ASCII_code @!match_chr; /*character used in a `|match|'*/ +ASCII_code @!n; /*the highest parameter number, as an ASCII digit*/ +match_chr='#';n='0';tally=0; +while ((p!=null)&&(tally < l)) + {@+if (p==q) @<Do magic computation@>; + @<Display token |p|, and |return| if there are problems@>; + p=link(p); + } +if (p!=null) print_esc("ETC."); +@.ETC@> + +} + +@ @<Display token |p|...@>= +if ((p < hi_mem_min)||(p > mem_end)) + {@+print_esc("CLOBBERED.");return; +@.CLOBBERED@> + } +if (info(p) >= cs_token_flag) print_cs(info(p)-cs_token_flag); +else{@+m=info(p)/0400;c=info(p)%0400; + if (info(p) < 0) print_esc("BAD."); +@.BAD@> + else@<Display the token $(|m|,|c|)$@>; + } + +@ The procedure usually ``learns'' the character code used for macro +parameters by seeing one in a |match| command before it runs into any +|out_param| commands. + +@<Display the token...@>= +switch (m) { +case left_brace: case right_brace: case math_shift: case tab_mark: case sup_mark: case sub_mark: case spacer: + case letter: case other_char: printn(c);@+break; +case mac_param: {@+printn(c);printn(c); + } @+break; +case out_param: {@+printn(match_chr); + if (c <= 9) print_char(c+'0'); + else{@+print_char('!');return; + } + } @+break; +case match: {@+match_chr=c;printn(c);incr(n);print_char(n); + if (n > '9') return; + } @+break; +case end_match: if (c==0) print("->");@+break; +@.->@> +default:print_esc("BAD."); +@.BAD@> +} + +@ Here's the way we sometimes want to display a token list, given a pointer +to its reference count; the pointer may be null. + +@p static void token_show(pointer @!p) +{@+if (p!=null) show_token_list(link(p), null, 10000000); +} + +@ The |print_meaning| subroutine displays |cur_cmd| and |cur_chr| in +symbolic form, including the expansion of a macro or mark. + +@p static void print_meaning(void) +{@+print_cmd_chr(cur_cmd, cur_chr); +if (cur_cmd >= call) + {@+print_char(':');print_ln();token_show(cur_chr); + } +else if (cur_cmd==top_bot_mark) + {@+print_char(':');print_ln(); + token_show(cur_mark[cur_chr]); + } +} + +@* Introduction to the syntactic routines. +Let's pause a moment now and try to look at the Big Picture. +The \TeX\ program consists of three main parts: syntactic routines, +semantic routines, and output routines. The chief purpose of the +syntactic routines is to deliver the user's input to the semantic routines, +one token at a time. The semantic routines act as an interpreter +responding to these tokens, which may be regarded as commands. And the +output routines are periodically called on to convert box-and-glue +lists into a compact set of instructions that will be sent +to a typesetter. We have discussed the basic data structures and utility +routines of \TeX, so we are good and ready to plunge into the real activity by +considering the syntactic routines. + +Our current goal is to come to grips with the |get_next| procedure, +which is the keystone of \TeX's input mechanism. Each call of |get_next| +sets the value of three variables |cur_cmd|, |cur_chr|, and |cur_cs|, +representing the next input token. +$$\vbox{\halign{#\hfil\cr + \hbox{|cur_cmd| denotes a command code from the long list of codes + given above;}\cr + \hbox{|cur_chr| denotes a character code or other modifier of the command + code;}\cr + \hbox{|cur_cs| is the |eqtb| location of the current control sequence,}\cr + \hbox{\qquad if the current token was a control sequence, + otherwise it's zero.}\cr}}$$ +Underlying this external behavior of |get_next| is all the machinery +necessary to convert from character files to tokens. At a given time we +may be only partially finished with the reading of several files (for +which \.{\\input} was specified), and partially finished with the expansion +of some user-defined macros and/or some macro parameters, and partially +finished with the generation of some text in a template for \.{\\halign}, +and so on. When reading a character file, special characters must be +classified as math delimiters, etc.; comments and extra blank spaces must +be removed, paragraphs must be recognized, and control sequences must be +found in the hash table. Furthermore there are occasions in which the +scanning routines have looked ahead for a word like `\.{plus}' but only +part of that word was found, hence a few characters must be put back +into the input and scanned again. + +To handle these situations, which might all be present simultaneously, +\TeX\ uses various stacks that hold information about the incomplete +activities, and there is a finite state control for each level of the +input mechanism. These stacks record the current state of an implicitly +recursive process, but the |get_next| procedure is not recursive. +Therefore it will not be difficult to translate these algorithms into +low-level languages that do not support recursion. + +@<Glob...@>= +static eight_bits @!cur_cmd; /*current command set by |get_next|*/ +static halfword @!cur_chr; /*operand of current command*/ +static pointer @!cur_cs; /*control sequence found here, zero if none found*/ +static halfword @!cur_tok; /*packed representative of |cur_cmd| and |cur_chr|*/ + +@ The |print_cmd_chr| routine prints a symbolic interpretation of a +command code and its modifier. This is used in certain `\.{You can\'t}' +error messages, and in the implementation of diagnostic routines like +\.{\\show}. + +The body of |print_cmd_chr| is a rather tedious listing of print +commands, and most of it is essentially an inverse to the |primitive| +routine that enters a \TeX\ primitive into |eqtb|. Therefore much of +this procedure appears elsewhere in the program, +together with the corresponding |primitive| calls. + +@d chr_cmd(A) {@+print(A);print_ASCII(chr_code); + } + +@<Declare the procedure called |print_cmd_chr|@>= +static void print_cmd_chr(quarterword @!cmd, halfword @!chr_code) +{@+int n; /*temp variable*/ +switch (cmd) { +case left_brace: chr_cmd("begin-group character ")@;@+break; +case right_brace: chr_cmd("end-group character ")@;@+break; +case math_shift: chr_cmd("math shift character ")@;@+break; +case mac_param: chr_cmd("macro parameter character ")@;@+break; +case sup_mark: chr_cmd("superscript character ")@;@+break; +case sub_mark: chr_cmd("subscript character ")@;@+break; +case endv: print("end of alignment template");@+break; +case spacer: chr_cmd("blank space ")@;@+break; +case letter: chr_cmd("the letter ")@;@+break; +case other_char: chr_cmd("the character ")@;@+break; +@t\4@>@<Cases of |print_cmd_chr| for symbolic printing of primitives@>@/ +default:print("[unknown command code!]"); +} +} + +@ Here is a procedure that displays the current command. + +@p static void show_cur_cmd_chr(void) +{@+int n; /*level of \.{\\if...\\fi} nesting*/ +int @!l; /*line where \.{\\if} started*/ +pointer @!p; +begin_diagnostic();print_nl("{"); +if (mode!=shown_mode) + {@+print_mode(mode);print(": ");shown_mode=mode; + } +print_cmd_chr(cur_cmd, cur_chr); +if (tracing_ifs > 0) + if (cur_cmd >= if_test) if (cur_cmd <= fi_or_else) + {@+print(": "); + if (cur_cmd==fi_or_else) + {@+print_cmd_chr(if_test, cur_if);print_char(' '); + n=0;l=if_line; + } + else{@+n=1;l=line; + } + p=cond_ptr; + while (p!=null) + {@+incr(n);p=link(p); + } + print("(level ");print_int(n);print_char(')');print_if_line(l); + } +print_char('}'); +end_diagnostic(false); +} + +@* Input stacks and states. +This implementation of +\TeX\ uses two different conventions for representing sequential stacks. +@^stack conventions@>@^conventions for representing stacks@> + +\yskip\hangg 1) If there is frequent access to the top entry, and if the +stack is essentially never empty, then the top entry is kept in a global +variable (even better would be a machine register), and the other entries +appear in the array $\\{stack}[0\to(\\{ptr}-1)]$. For example, the +semantic stack described above is handled this way, and so is the input +stack that we are about to study. + +\yskip\hangg 2) If there is infrequent top access, the entire stack contents +are in the array $\\{stack}[0\to(\\{ptr}-1)]$. For example, the |save_stack| +is treated this way, as we have seen. + +\yskip\noindent +The state of \TeX's input mechanism appears in the input stack, whose +entries are records with six fields, called |state|, |index|, |start|, |loc|, +|limit|, and |name|. This stack is maintained with +convention~(1), so it is declared in the following way: + +@<Types...@>= +typedef struct { + quarterword @!state_field, @!index_field; + halfword @!start_field, @!loc_field, @!limit_field, @!name_field; + } in_state_record; + +@ @<Glob...@>= +static in_state_record @!input_stack[stack_size+1]; +static int @!input_ptr; /*first unused location of |input_stack|*/ +static int @!max_in_stack; /*largest value of |input_ptr| when pushing*/ +static in_state_record @!cur_input; + /*the ``top'' input state, according to convention (1)*/ + +@ We've already defined the special variable |loc====cur_input.loc_field| +in our discussion of basic input-output routines. The other components of +|cur_input| are defined in the same way: + +@d state cur_input.state_field /*current scanner state*/ +@d index cur_input.index_field /*reference for buffer information*/ +@d start cur_input.start_field /*starting position in |buffer|*/ +@d limit cur_input.limit_field /*end of current line in |buffer|*/ +@d name cur_input.name_field /*name of the current file*/ + +@ Let's look more closely now at the control variables +(|state|,~|index|,~|start|,~|loc|,~|limit|,~|name|), +assuming that \TeX\ is reading a line of characters that have been input +from some file or from the user's terminal. There is an array called +|buffer| that acts as a stack of all lines of characters that are +currently being read from files, including all lines on subsidiary +levels of the input stack that are not yet completed. \TeX\ will return to +the other lines when it is finished with the present input file. + +(Incidentally, on a machine with byte-oriented addressing, it might be +appropriate to combine |buffer| with the |str_pool| array, +letting the buffer entries grow downward from the top of the string pool +and checking that these two tables don't bump into each other.) + +The line we are currently working on begins in position |start| of the +buffer; the next character we are about to read is |buffer[loc]|; and +|limit| is the location of the last character present. If |loc > limit|, +the line has been completely read. Usually |buffer[limit]| is the +|end_line_char|, denoting the end of a line, but this is not +true if the current line is an insertion that was entered on the user's +terminal in response to an error message. + +The |name| variable is a string number that designates the name of +the current file, if we are reading a text file. It is zero if we +are reading from the terminal; it is |n+1| if we are reading from +input stream |n|, where |0 <= n <= 16|. (Input stream 16 stands for +an invalid stream number; in such cases the input is actually from +the terminal, under control of the procedure |read_toks|.) +Finally |18 <= name <= 19| indicates that we are reading a pseudo file +created by the \.{\\scantokens} command. + +The |state| variable has one of three values, when we are scanning such +files: +$$\baselineskip 15pt\vbox{\halign{#\hfil\cr +1) |state==mid_line| is the normal state.\cr +2) |state==skip_blanks| is like |mid_line|, but blanks are ignored.\cr +3) |state==new_line| is the state at the beginning of a line.\cr}}$$ +These state values are assigned numeric codes so that if we add the state +code to the next character's command code, we get distinct values. For +example, `|mid_line+spacer|' stands for the case that a blank +space character occurs in the middle of a line when it is not being +ignored; after this case is processed, the next value of |state| will +be |skip_blanks|. + +@d mid_line 1 /*|state| code when scanning a line of characters*/ +@d skip_blanks (2+max_char_code) /*|state| code when ignoring blanks*/ +@d new_line (3+max_char_code+max_char_code) /*|state| code at start of line*/ + +@ Additional information about the current line is available via the +|index| variable, which counts how many lines of characters are present +in the buffer below the current level. We have |index==0| when reading +from the terminal and prompting the user for each line; then if the user types, +e.g., `\.{\\input paper}', we will have |index==1| while reading +the file \.{paper.tex}. However, it does not follow that |index| is the +same as the input stack pointer, since many of the levels on the input +stack may come from token lists. For example, the instruction `\.{\\input +paper}' might occur in a token list. + +The global variable |in_open| is equal to the |index| +value of the highest non-token-list level. Thus, the number of partially read +lines in the buffer is |in_open+1|, and we have |in_open==index| +when we are not reading a token list. + +If we are not currently reading from the terminal, or from an input +stream, we are reading from the file variable |input_file[index]|. We use +the notation |terminal_input| as a convenient abbreviation for |name==0|, +and |cur_file| as an abbreviation for |input_file[index]|. + +The global variable |line| contains the line number in the topmost +open file, for use in error messages. If we are not reading from +the terminal, |line_stack[index]| holds the line number for the +enclosing level, so that |line| can be restored when the current +file has been read. Line numbers should never be negative, since the +negative of the current line number is used to identify the user's output +routine in the |mode_line| field of the semantic nest entries. + +If more information about the input state is needed, it can be +included in small arrays like those shown here. For example, +the current page or segment number in the input file might be +put into a variable |@!page|, maintained for enclosing levels in +`\ignorespaces|@!page_stack: array[1 dotdot max_in_open]int|\unskip' +by analogy with |line_stack|. +@^system dependencies@> + +@d terminal_input (name==0) /*are we reading from the terminal?*/ +@d cur_file input_file[index] /*the current |alpha_file| variable*/ + +@<Glob...@>= +static int @!in_open; /*the number of lines in the buffer, less one*/ +static int @!open_parens; /*the number of open text files*/ +static alpha_file @!input_file0[max_in_open], *const @!input_file = @!input_file0-1; +int @!line; /*current line number in the current source file*/ +static int @!line_stack0[max_in_open], *const @!line_stack = @!line_stack0-1; + +@ Users of \TeX\ sometimes forget to balance left and right braces properly, +and one of the ways \TeX\ tries to spot such errors is by considering an +input file as broken into subfiles by control sequences that +are declared to be \.{\\outer}. + +A variable called |scanner_status| tells \TeX\ whether or not to complain +when a subfile ends. This variable has six possible values: + +\yskip\hang|normal|, means that a subfile can safely end here without incident. + +\yskip\hang|skipping|, means that a subfile can safely end here, but not a file, +because we're reading past some conditional text that was not selected. + +\yskip\hang|defining|, means that a subfile shouldn't end now because a +macro is being defined. + +\yskip\hang|matching|, means that a subfile shouldn't end now because a +macro is being used and we are searching for the end of its arguments. + +\yskip\hang|aligning|, means that a subfile shouldn't end now because we are +not finished with the preamble of an \.{\\halign} or \.{\\valign}. + +\yskip\hang|absorbing|, means that a subfile shouldn't end now because we are +reading a balanced token list for \.{\\message}, \.{\\write}, etc. + +\yskip\noindent +If the |scanner_status| is not |normal|, the variable |warning_index| points +to the |eqtb| location for the relevant control sequence name to print +in an error message. + +@d skipping 1 /*|scanner_status| when passing conditional text*/ +@d defining 2 /*|scanner_status| when reading a macro definition*/ +@d matching 3 /*|scanner_status| when reading macro arguments*/ +@d aligning 4 /*|scanner_status| when reading an alignment preamble*/ +@d absorbing 5 /*|scanner_status| when reading a balanced text*/ + +@<Glob...@>= +static int @!scanner_status; /*can a subfile end now?*/ +static pointer @!warning_index; /*identifier relevant to non-|normal| scanner status*/ +static pointer @!def_ref; /*reference count of token list being defined*/ + +@ Here is a procedure that uses |scanner_status| to print a warning message +when a subfile has ended, and at certain other crucial times: + +@<Declare the procedure called |runaway|@>= +static void runaway(void) +{@+pointer p; /*head of runaway list*/ +if (scanner_status > skipping) + {@+print_nl("Runaway "); +@.Runaway...@> + switch (scanner_status) { + case defining: {@+print("definition");p=def_ref; + } @+break; + case matching: {@+print("argument");p=temp_head; + } @+break; + case aligning: {@+print("preamble");p=hold_head; + } @+break; + case absorbing: {@+print("text");p=def_ref; + } + } /*there are no other cases*/ + print_char('?');print_ln();show_token_list(link(p), null, error_line-10); + } +} + +@ However, all this discussion about input state really applies only to the +case that we are inputting from a file. There is another important case, +namely when we are currently getting input from a token list. In this case +|state==token_list|, and the conventions about the other state variables +are different: + +\yskip\hang|loc| is a pointer to the current node in the token list, i.e., +the node that will be read next. If |loc==null|, the token list has been +fully read. + +\yskip\hang|start| points to the first node of the token list; this node +may or may not contain a reference count, depending on the type of token +list involved. + +\yskip\hang|token_type|, which takes the place of |index| in the +discussion above, is a code number that explains what kind of token list +is being scanned. + +\yskip\hang|name| points to the |eqtb| address of the control sequence +being expanded, if the current token list is a macro. + +\yskip\hang|param_start|, which takes the place of |limit|, tells where +the parameters of the current macro begin in the |param_stack|, if the +current token list is a macro. + +\yskip\noindent The |token_type| can take several values, depending on +where the current token list came from: + +\yskip\hang|parameter|, if a parameter is being scanned; + +\hang|u_template|, if the \<u_j> part of an alignment +template is being scanned; + +\hang|v_template|, if the \<v_j> part of an alignment +template is being scanned; + +\hang|backed_up|, if the token list being scanned has been inserted as +`to be read again'. + +\hang|inserted|, if the token list being scanned has been inserted as +the text expansion of a \.{\\count} or similar variable; + +\hang|macro|, if a user-defined control sequence is being scanned; + +\hang|output_text|, if an \.{\\output} routine is being scanned; + +\hang|every_par_text|, if the text of \.{\\everypar} is being scanned; + +\hang|every_math_text|, if the text of \.{\\everymath} is being scanned; + +\hang|every_display_text|, if the text of \.{\\everydisplay} is being scanned; + +\hang|every_hbox_text|, if the text of \.{\\everyhbox} is being scanned; + +\hang|every_vbox_text|, if the text of \.{\\everyvbox} is being scanned; + +\hang|every_job_text|, if the text of \.{\\everyjob} is being scanned; + +\hang|every_cr_text|, if the text of \.{\\everycr} is being scanned; + +\hang|mark_text|, if the text of a \.{\\mark} is being scanned; + +\hang|write_text|, if the text of a \.{\\write} is being scanned. + +\yskip\noindent +The codes for |output_text|, |every_par_text|, etc., are equal to a constant +plus the corresponding codes for token list parameters |output_routine_loc|, +|every_par_loc|, etc. The token list begins with a reference count if and +only if |token_type >= macro|. +@^reference counts@> + +Since \eTeX's additional token list parameters precede |toks_base|, the +corresponding token types must precede |write_text|. + +@d token_list 0 /*|state| code when scanning a token list*/ +@d token_type index /*type of current token list*/ +@d param_start limit /*base of macro parameters in |param_stack|*/ +@d parameter 0 /*|token_type| code for parameter*/ +@d u_template 1 /*|token_type| code for \<u_j> template*/ +@d v_template 2 /*|token_type| code for \<v_j> template*/ +@d backed_up 3 /*|token_type| code for text to be reread*/ +@d inserted 4 /*|token_type| code for inserted texts*/ +@d macro 5 /*|token_type| code for defined control sequences*/ +@d output_text 6 /*|token_type| code for output routines*/ +@d every_par_text 7 /*|token_type| code for \.{\\everypar}*/ +@d every_math_text 8 /*|token_type| code for \.{\\everymath}*/ +@d every_display_text 9 /*|token_type| code for \.{\\everydisplay}*/ +@d every_hbox_text 10 /*|token_type| code for \.{\\everyhbox}*/ +@d every_vbox_text 11 /*|token_type| code for \.{\\everyvbox}*/ +@d every_job_text 12 /*|token_type| code for \.{\\everyjob}*/ +@d every_cr_text 13 /*|token_type| code for \.{\\everycr}*/ +@d mark_text 14 /*|token_type| code for \.{\\topmark}, etc.*/ +@# +@d eTeX_text_offset (output_routine_loc-output_text) +@d every_eof_text (every_eof_loc-eTeX_text_offset) + /*|token_type| code for \.{\\everyeof}*/ +@# +@d write_text (toks_base-eTeX_text_offset) /*|token_type| code for \.{\\write}*/ + +@ The |param_stack| is an auxiliary array used to hold pointers to the token +lists for parameters at the current level and subsidiary levels of input. +This stack is maintained with convention (2), and it grows at a different +rate from the others. + +@<Glob...@>= +static pointer @!param_stack[param_size+1]; + /*token list pointers for parameters*/ +static int @!param_ptr; /*first unused entry in |param_stack|*/ +static int @!max_param_stack; + /*largest value of |param_ptr|, will be | <= param_size+9|*/ + +@ The input routines must also interact with the processing of +\.{\\halign} and \.{\\valign}, since the appearance of tab marks and +\.{\\cr} in certain places is supposed to trigger the beginning of special +\<v_j> template text in the scanner. This magic is accomplished by an +|align_state| variable that is increased by~1 when a `\.{\char'173}' is +scanned and decreased by~1 when a `\.{\char'175}' is scanned. The |align_state| +is nonzero during the \<u_j> template, after which it is set to zero; the +\<v_j> template begins when a tab mark or \.{\\cr} occurs at a time that +|align_state==0|. + +@<Glob...@>= +static int @!align_state; /*group level with respect to current alignment*/ + +@ Thus, the ``current input state'' can be very complicated indeed; there +can be many levels and each level can arise in a variety of ways. The +|show_context| procedure, which is used by \TeX's error-reporting routine to +print out the current input state on all levels down to the most recent +line of characters from an input file, illustrates most of these conventions. +The global variable |base_ptr| contains the lowest level that was +displayed by this procedure. + +@<Glob...@>= +static int @!base_ptr; /*shallowest level shown by |show_context|*/ + +@ The status at each level is indicated by printing two lines, where the first +line indicates what was read so far and the second line shows what remains +to be read. The context is cropped, if necessary, so that the first line +contains at most |half_error_line| characters, and the second contains +at most |error_line|. Non-current input levels whose |token_type| is +`|backed_up|' are shown only if they have not been fully read. + +@p static void show_context(void) /*prints where the scanner is*/ +{@+ +int old_setting; /*saved |selector| setting*/ +int @!nn; /*number of contexts shown so far, less one*/ +bool @!bottom_line; /*have we reached the final context to be shown?*/ +@<Local variables for formatting calculations@>@/ +base_ptr=input_ptr;input_stack[base_ptr]=cur_input; + /*store current state*/ +nn=-1;bottom_line=false; +loop@+{@+cur_input=input_stack[base_ptr]; /*enter into the context*/ + if ((state!=token_list)) + if ((name > 19)||(base_ptr==0)) bottom_line=true; + if ((base_ptr==input_ptr)||bottom_line||(nn < error_context_lines)) + @<Display the current context@>@; + else if (nn==error_context_lines) + {@+print_nl("...");incr(nn); /*omitted if |error_context_lines < 0|*/ + } + if (bottom_line) goto done; + decr(base_ptr); + } +done: cur_input=input_stack[input_ptr]; /*restore original state*/ +} + +@ @<Display the current context@>= +{@+if ((base_ptr==input_ptr)||(state!=token_list)|| + (token_type!=backed_up)||(loc!=null)) + /*we omit backed-up token lists that have already been read*/ + {@+tally=0; /*get ready to count characters*/ + old_setting=selector; + if (state!=token_list) + {@+@<Print location of current line@>; + @<Pseudoprint the line@>; + } + else{@+@<Print type of token list@>; + @<Pseudoprint the token list@>; + } + selector=old_setting; /*stop pseudoprinting*/ + @<Print two lines using the tricky pseudoprinted information@>; + incr(nn); + } +} + +@ This routine should be changed, if necessary, to give the best possible +indication of where the current line resides in the input file. +For example, on some systems it is best to print both a page and line number. +@^system dependencies@> + +@<Print location of current line@>= +if (name <= 17) + if (terminal_input) + if (base_ptr==0) print_nl("<*>");else print_nl("<insert> "); + else{@+print_nl("<read "); + if (name==17) print_char('*');@+else print_int(name-1); +@.*\relax@> + print_char('>'); + } +else{@+print_nl("l."); + if (index==in_open) print_int(line); + else print_int(line_stack[index+1]); /*input from a pseudo file*/ + } +print_char(' ') + +@ @<Print type of token list@>= +switch (token_type) { +case parameter: print_nl("<argument> ");@+break; +case u_template: case v_template: print_nl("<template> ");@+break; +case backed_up: if (loc==null) print_nl("<recently read> "); + else print_nl("<to be read again> ");@+break; +case inserted: print_nl("<inserted text> ");@+break; +case macro: {@+print_ln();print_cs(name); + } @+break; +case output_text: print_nl("<output> ");@+break; +case every_par_text: print_nl("<everypar> ");@+break; +case every_math_text: print_nl("<everymath> ");@+break; +case every_display_text: print_nl("<everydisplay> ");@+break; +case every_hbox_text: print_nl("<everyhbox> ");@+break; +case every_vbox_text: print_nl("<everyvbox> ");@+break; +case every_job_text: print_nl("<everyjob> ");@+break; +case every_cr_text: print_nl("<everycr> ");@+break; +case mark_text: print_nl("<mark> ");@+break; +case every_eof_text: print_nl("<everyeof> ");@+break; +case write_text: print_nl("<write> ");@+break; +default:print_nl("?"); /*this should never happen*/ +} + +@ Here it is necessary to explain a little trick. We don't want to store a long +string that corresponds to a token list, because that string might take up +lots of memory; and we are printing during a time when an error message is +being given, so we dare not do anything that might overflow one of \TeX's +tables. So `pseudoprinting' is the answer: We enter a mode of printing +that stores characters into a buffer of length |error_line|, where character +$k+1$ is placed into \hbox{|trick_buf[k%error_line]|} if +|k < trick_count|, otherwise character |k| is dropped. Initially we set +|tally=0| and |trick_count=1000000|; then when we reach the +point where transition from line 1 to line 2 should occur, we +set |first_count=tally| and |trick_count=@tmax@>(error_line, +tally+1+error_line-half_error_line)|. At the end of the +pseudoprinting, the values of |first_count|, |tally|, and +|trick_count| give us all the information we need to print the two lines, +and all of the necessary text is in |trick_buf|. + +Namely, let |l| be the length of the descriptive information that appears +on the first line. The length of the context information gathered for that +line is |k==first_count|, and the length of the context information +gathered for line~2 is $m=\min(|tally|, |trick_count|)-k$. If |l+k <= h|, +where |h==half_error_line|, we print |trick_buf[0 dotdot k-1]| after the +descriptive information on line~1, and set |n=l+k|; here |n| is the +length of line~1. If $l+k>h$, some cropping is necessary, so we set |n=h| +and print `\.{...}' followed by +$$\hbox{|trick_buf[(l+k-h+3)dotdot k-1]|,}$$ +where subscripts of |trick_buf| are circular modulo |error_line|. The +second line consists of |n|~spaces followed by |trick_buf[k dotdot(k+m-1)]|, +unless |n+m > error_line|; in the latter case, further cropping is done. +This is easier to program than to explain. + +@<Local variables for formatting...@>= +int @!i; /*index into |buffer|*/ +int @!j; /*end of current line in |buffer|*/ +int @!l; /*length of descriptive information on line 1*/ +int @!m; /*context information gathered for line 2*/ +int @!n; /*length of line 1*/ +int @!p; /*starting or ending place in |trick_buf|*/ +int @!q; /*temporary index*/ + +@ The following code sets up the print routines so that they will gather +the desired information. + +@d begin_pseudoprint + {@+l=tally;tally=0;selector=pseudo; + trick_count=1000000; + } +@d set_trick_count + {@+first_count=tally; + trick_count=tally+1+error_line-half_error_line; + if (trick_count < error_line) trick_count=error_line; + } + +@ And the following code uses the information after it has been gathered. + +@<Print two lines using the tricky pseudoprinted information@>= +if (trick_count==1000000) set_trick_count; + /*|set_trick_count| must be performed*/ +if (tally < trick_count) m=tally-first_count; +else m=trick_count-first_count; /*context on line 2*/ +if (l+first_count <= half_error_line) + {@+p=0;n=l+first_count; + } +else{@+print("...");p=l+first_count-half_error_line+3; + n=half_error_line; + } +for (q=p; q<=first_count-1; q++) print_char(trick_buf[q%error_line]); +print_ln(); +for (q=1; q<=n; q++) print_char(' '); /*print |n| spaces to begin line~2*/ +if (m+n <= error_line) p=first_count+m;else p=first_count+(error_line-n-3); +for (q=first_count; q<=p-1; q++) print_char(trick_buf[q%error_line]); +if (m+n > error_line) print("...") + +@ But the trick is distracting us from our current goal, which is to +understand the input state. So let's concentrate on the data structures that +are being pseudoprinted as we finish up the |show_context| procedure. + +@<Pseudoprint the line@>= +begin_pseudoprint; +if (buffer[limit]==end_line_char) j=limit; +else j=limit+1; /*determine the effective end of the line*/ +if (j > 0) for (i=start; i<=j-1; i++) + {@+if (i==loc) set_trick_count; + printn(buffer[i]); + } + +@ @<Pseudoprint the token list@>= +begin_pseudoprint; +if (token_type < macro) show_token_list(start, loc, 100000); +else show_token_list(link(start), loc, 100000) /*avoid reference count*/ + +@ Here is the missing piece of |show_token_list| that is activated when the +token beginning line~2 is about to be shown: + +@<Do magic computation@>=set_trick_count + +@* Maintaining the input stacks. +The following subroutines change the input status in commonly needed ways. + +First comes |push_input|, which stores the current state and creates a +new level (having, initially, the same properties as the old). + +@d push_input @t@> /*enter a new input level, save the old*/ + {@+if (input_ptr > max_in_stack) + {@+max_in_stack=input_ptr; + if (input_ptr==stack_size) overflow("input stack size", stack_size); +@:TeX capacity exceeded input stack size}{\quad input stack size@> + } + input_stack[input_ptr]=cur_input; /*stack the record*/ + incr(input_ptr); + } + +@ And of course what goes up must come down. + +@d pop_input @t@> /*leave an input level, re-enter the old*/ + {@+decr(input_ptr);cur_input=input_stack[input_ptr]; + } + +@ Here is a procedure that starts a new level of token-list input, given +a token list |p| and its type |t|. If |t==macro|, the calling routine should +set |name| and |loc|. + +@d back_list(A) begin_token_list(A, backed_up) /*backs up a simple token list*/ +@d ins_list(A) begin_token_list(A, inserted) /*inserts a simple token list*/ + +@p void begin_token_list(pointer @!p, quarterword @!t) +{@+push_input;state=token_list;start=p;token_type=t; +if (t >= macro) /*the token list starts with a reference count*/ + {@+add_token_ref(p); + if (t==macro) param_start=param_ptr; + else{@+loc=link(p); + if (tracing_macros > 1) + {@+begin_diagnostic();print_nl(""); + switch (t) { + case mark_text: print_esc("mark");@+break; + case write_text: print_esc("write");@+break; + default:print_cmd_chr(assign_toks, t-output_text+output_routine_loc); + } @/ + print("->");token_show(p);end_diagnostic(false); + } + } + } +else loc=p; +} + +@ When a token list has been fully scanned, the following computations +should be done as we leave that level of input. The |token_type| tends +to be equal to either |backed_up| or |inserted| about 2/3 of the time. +@^inner loop@> + +@p static void end_token_list(void) /*leave a token-list input level*/ +{@+if (token_type >= backed_up) /*token list to be deleted*/ + {@+if (token_type <= inserted) flush_list(start); + else{@+delete_token_ref(start); /*update reference count*/ + if (token_type==macro) /*parameters must be flushed*/ + while (param_ptr > param_start) + {@+decr(param_ptr); + flush_list(param_stack[param_ptr]); + } + } + } +else if (token_type==u_template) + if (align_state > 500000) align_state=0; + else fatal_error("(interwoven alignment preambles are not allowed)"); +@.interwoven alignment preambles...@> +pop_input; +check_interrupt; +} + +@ Sometimes \TeX\ has read too far and wants to ``unscan'' what it has +seen. The |back_input| procedure takes care of this by putting the token +just scanned back into the input stream, ready to be read again. This +procedure can be used only if |cur_tok| represents the token to be +replaced. Some applications of \TeX\ use this procedure a lot, +so it has been slightly optimized for speed. +@^inner loop@> + +@p static void back_input(void) /*undoes one token of input*/ +{@+pointer p; /*a token list of length one*/ +while ((state==token_list)&&(loc==null)&&(token_type!=v_template)) + end_token_list(); /*conserve stack space*/ +p=get_avail();info(p)=cur_tok; +if (cur_tok < right_brace_limit) + if (cur_tok < left_brace_limit) decr(align_state); + else incr(align_state); +push_input;state=token_list;start=p;token_type=backed_up; +loc=p; /*that was |back_list(p)|, without procedure overhead*/ +} + +@ @<Insert token |p| into \TeX's input@>= +{@+t=cur_tok;cur_tok=p; +if (a) + {@+p=get_avail();info(p)=cur_tok;link(p)=loc;loc=p;start=p; + if (cur_tok < right_brace_limit) + if (cur_tok < left_brace_limit) decr(align_state); + else incr(align_state); + } +else{@+back_input();a=eTeX_ex; + } +cur_tok=t; +} + +@ The |back_error| routine is used when we want to replace an offending token +just before issuing an error message. This routine, like |back_input|, +requires that |cur_tok| has been set. We disable interrupts during the +call of |back_input| so that the help message won't be lost. + +@p static void back_error(void) /*back up one token and call |error|*/ +{@+OK_to_interrupt=false;back_input();OK_to_interrupt=true;error(); +} +@# +static void ins_error(void) /*back up one inserted token and call |error|*/ +{@+OK_to_interrupt=false;back_input();token_type=inserted; +OK_to_interrupt=true;error(); +} + +@ The |begin_file_reading| procedure starts a new level of input for lines +of characters to be read from a file, or as an insertion from the +terminal. It does not take care of opening the file, nor does it set |loc| +or |limit| or |line|. +@^system dependencies@> + +@p static void begin_file_reading(void) +{@+if (in_open==max_in_open) overflow("text input levels", max_in_open); +@:TeX capacity exceeded text input levels}{\quad text input levels@> +if (first==buf_size) overflow("buffer size", buf_size); +@:TeX capacity exceeded buffer size}{\quad buffer size@> +incr(in_open);push_input;index=in_open;@/ +source_filename_stack[index]=0; /* k\TeX\ */ +eof_seen[index]=false; +grp_stack[index]=cur_boundary;if_stack[index]=cond_ptr; +line_stack[index]=line;start=first;state=mid_line; +name=0; /*|terminal_input| is now |true|*/ +} + +@ Conversely, the variables must be downdated when such a level of input +is finished: + +@p static void end_file_reading(void) +{@+first=start;line=line_stack[index]; +if ((name==18)||(name==19)) pseudo_close();else +if (name > 17) a_close(&cur_file); /*forget it*/ +pop_input;decr(in_open); +} + +@ In order to keep the stack from overflowing during a long sequence of +inserted `\.{\\show}' commands, the following routine removes completed +error-inserted lines from memory. + +@p static void clear_for_error_prompt(void) +{@+while ((state!=token_list)&&terminal_input&&@| + (input_ptr > 0)&&(loc > limit)) end_file_reading(); +print_ln();clear_terminal; +} + +@ To get \TeX's whole input mechanism going, we perform the following +actions. + +@<Initialize the input routines@>= +{@+input_ptr=0;max_in_stack=0; +in_open=0;open_parens=0;max_buf_stack=0; +grp_stack[0]=0;if_stack[0]=null; +param_ptr=0;max_param_stack=0; +first=buf_size;@/do@+{buffer[first]=0;decr(first);}@+ while (!(first==0)); +scanner_status=normal;warning_index=null;first=1; +state=new_line;start=1;index=0;line=0;name=0; +force_eof=false; +align_state=1000000;@/ +if (!init_terminal()) exit(0); +limit=last;first=last+1; /*|init_terminal| has set |loc| and |last|*/ +} + +@* Getting the next token. +The heart of \TeX's input mechanism is the |get_next| procedure, which +we shall develop in the next few sections of the program. Perhaps we +shouldn't actually call it the ``heart,'' however, because it really acts +as \TeX's eyes and mouth, reading the source files and gobbling them up. +And it also helps \TeX\ to regurgitate stored token lists that are to be +processed again. +@^eyes and mouth@> + +The main duty of |get_next| is to input one token and to set |cur_cmd| +and |cur_chr| to that token's command code and modifier. Furthermore, if +the input token is a control sequence, the |eqtb| location of that control +sequence is stored in |cur_cs|; otherwise |cur_cs| is set to zero. + +Underlying this simple description is a certain amount of complexity +because of all the cases that need to be handled. +However, the inner loop of |get_next| is reasonably short and fast. + +When |get_next| is asked to get the next token of a \.{\\read} line, +it sets |cur_cmd==cur_chr==cur_cs==0| in the case that no more tokens +appear on that line. (There might not be any tokens at all, if the +|end_line_char| has |ignore| as its catcode.) + +@ The value of |par_loc| is the |eqtb| address of `\.{\\par}'. This quantity +is needed because a blank line of input is supposed to be exactly equivalent +to the appearance of \.{\\par}; we must set |cur_cs=par_loc| +when detecting a blank line. + +@<Glob...@>= +static pointer @!par_loc; /*location of `\.{\\par}' in |eqtb|*/ +static halfword @!par_token; /*token representing `\.{\\par}'*/ + +@ @<Put each...@>= +primitive("par", par_end, 256); /*cf.\ |scan_file_name|*/ +@!@:par\_}{\.{\\par} primitive@> +par_loc=cur_val;par_token=cs_token_flag+par_loc; + +@ @<Cases of |print_cmd_chr|...@>= +case par_end: print_esc("par");@+break; + +@ Before getting into |get_next|, let's consider the subroutine that +is called when an `\.{\\outer}' control sequence has been scanned or +when the end of a file has been reached. These two cases are distinguished +by |cur_cs|, which is zero at the end of a file. + +@p static void check_outer_validity(void) +{@+pointer p; /*points to inserted token list*/ +pointer @!q; /*auxiliary pointer*/ +if (scanner_status!=normal) + {@+deletions_allowed=false; + @<Back up an outer control sequence so that it can be reread@>; + if (scanner_status > skipping) + @<Tell the user what has run away and try to recover@>@; + else{@+print_err("Incomplete ");print_cmd_chr(if_test, cur_if); +@.Incomplete \\if...@> + print("; all text was ignored after line ");print_int(skip_line); + help3("A forbidden control sequence occurred in skipped text.",@/ + "This kind of error happens when you say `\\if...' and forget",@/ + "the matching `\\fi'. I've inserted a `\\fi'; this might work."); + if (cur_cs!=0) cur_cs=0; + else help_line[2]=@| + "The file ended while I was skipping conditional text."; + cur_tok=cs_token_flag+frozen_fi;ins_error(); + } + deletions_allowed=true; + } +} + +@ An outer control sequence that occurs in a \.{\\read} will not be reread, +since the error recovery for \.{\\read} is not very powerful. + +@<Back up an outer control sequence so that it can be reread@>= +if (cur_cs!=0) + {@+if ((state==token_list)||(name < 1)||(name > 17)) + {@+p=get_avail();info(p)=cs_token_flag+cur_cs; + back_list(p); /*prepare to read the control sequence again*/ + } + cur_cmd=spacer;cur_chr=' '; /*replace it by a space*/ + } + +@ @<Tell the user what has run away...@>= +{@+runaway(); /*print a definition, argument, or preamble*/ +if (cur_cs==0) print_err("File ended"); +@.File ended while scanning...@> +else{@+cur_cs=0;print_err("Forbidden control sequence found"); +@.Forbidden control sequence...@> + } +print(" while scanning "); +@<Print either `\.{definition}' or `\.{use}' or `\.{preamble}' or `\.{text}', and +insert tokens that should lead to recovery@>; +print(" of ");sprint_cs(warning_index); +help4("I suspect you have forgotten a `}', causing me",@/ +"to read past where you wanted me to stop.",@/ +"I'll try to recover; but if the error is serious,",@/ +"you'd better type `E' or `X' now and fix your file.");@/ +error(); +} + +@ The recovery procedure can't be fully understood without knowing more +about the \TeX\ routines that should be aborted, but we can sketch the +ideas here: For a runaway definition we will insert a right brace; for a +runaway preamble, we will insert a special \.{\\cr} token and a right +brace; and for a runaway argument, we will set |long_state| to +|outer_call| and insert \.{\\par}. + +@<Print either `\.{definition}' or...@>= +p=get_avail(); +switch (scanner_status) { +case defining: {@+print("definition");info(p)=right_brace_token+'}'; + } @+break; +case matching: {@+print("use");info(p)=par_token;long_state=outer_call; + } @+break; +case aligning: {@+print("preamble");info(p)=right_brace_token+'}';q=p; + p=get_avail();link(p)=q;info(p)=cs_token_flag+frozen_cr; + align_state=-1000000; + } @+break; +case absorbing: {@+print("text");info(p)=right_brace_token+'}'; + } +} /*there are no other cases*/ +ins_list(p) + +@ We need to mention a procedure here that may be called by |get_next|. + +@p static void firm_up_the_line(void); + +@ Now we're ready to take the plunge into |get_next| itself. Parts of +this routine are executed more often than any other instructions of \TeX. +@^mastication@>@^inner loop@> + +@p static void get_next(void) /*sets |cur_cmd|, |cur_chr|, |cur_cs| to next token*/ +{@+ /*go here to get the next input token*/ + /*go here to eat the next character from a file*/ + /*go here to digest it again*/ + /*go here to start looking for a control sequence*/ + /*go here when a control sequence has been found*/ + /*go here when the next input token has been got*/ +int k; /*an index into |buffer|*/ +halfword @!t; /*a token*/ +int @!cat; /*|cat_code(cur_chr)|, usually*/ +ASCII_code @!c, @!cc; /*constituents of a possible expanded code*/ +int @!d; /*number of excess characters in an expanded code*/ +restart: cur_cs=0; +if (state!=token_list) +@<Input from external file, |goto restart| if no input found@>@; +else@<Input from token list, |goto restart| if end of list or if a parameter needs +to be expanded@>; +@<If an alignment entry has just ended, take appropriate action@>; +} + +@ An alignment entry ends when a tab or \.{\\cr} occurs, provided that the +current level of braces is the same as the level that was present at the +beginning of that alignment entry; i.e., provided that |align_state| has +returned to the value it had after the \<u_j> template for that entry. +@^inner loop@> + +@<If an alignment entry has just ended, take appropriate action@>= +if (cur_cmd <= car_ret) if (cur_cmd >= tab_mark) if (align_state==0) + @<Insert the \(v)\<v_j> template and |goto restart|@>@; + +@ @<Input from external file, |goto restart| if no input found@>= +@^inner loop@> +{@+get_cur_chr: if (loc <= limit) /*current line not yet finished*/ + {@+cur_chr=buffer[loc];incr(loc); + reswitch: cur_cmd=cat_code(cur_chr); + @<Change state if necessary, and |goto switch| if the current character should be +ignored, or |goto reswitch| if the current character changes to another@>; + } +else{@+state=new_line;@/ + @<Move to next line of file, or |goto restart| if there is no next line, or |return| +if a \.{\\read} line has finished@>; + check_interrupt; + goto get_cur_chr; + } +} + +@ The following 48-way switch accomplishes the scanning quickly, assuming +that a decent \PASCAL\ compiler has translated the code. Note that the numeric +values for |mid_line|, |skip_blanks|, and |new_line| are spaced +apart from each other by |max_char_code+1|, so we can add a character's +command code to the state to get a single number that characterizes both. + +@d any_state_plus(A) case mid_line+A: case skip_blanks+A: case new_line+A + +@<Change state if necessary...@>= +switch (state+cur_cmd) { +@<Cases where character is ignored@>: goto get_cur_chr; +any_state_plus(escape): @<Scan a control sequence and set |state:=skip_blanks| or +|mid_line|@>@;@+break; +any_state_plus(active_char): @<Process an active-character control sequence and set +|state:=mid_line|@>@;@+break; +any_state_plus(sup_mark): @<If this |sup_mark| starts an expanded character like~\.{\^\^A} +or~\.{\^\^df}, then |goto reswitch|, otherwise set |state:=mid_line|@>@;@+break; +any_state_plus(invalid_char): @<Decry the invalid character and |goto restart|@>@; +@t\4@>@<Handle situations involving spaces, braces, changes of state@>@; +default:do_nothing; +} + +@ @<Cases where character is ignored@>= +any_state_plus(ignore): case skip_blanks+spacer: case new_line+spacer + +@ We go to |restart| instead of to |get_cur_chr|, because |state| might equal +|token_list| after the error has been dealt with +(cf.\ |clear_for_error_prompt|). + +@<Decry the invalid...@>= +{@+print_err("Text line contains an invalid character"); +@.Text line contains...@> +help2("A funny symbol that I can't read has just been input.",@/ +"Continue, and I'll forget that it ever happened.");@/ +deletions_allowed=false;error();deletions_allowed=true; +goto restart; +} + +@ @d add_delims_to(A) A+math_shift: A+tab_mark: A+mac_param: + A+sub_mark: A+letter: A+other_char + +@<Handle situations involving spaces, braces, changes of state@>= +case mid_line+spacer: @<Enter |skip_blanks| state, emit a space@>@;@+break; +case mid_line+car_ret: @<Finish line, emit a space@>@;@+break; +case skip_blanks+car_ret: any_state_plus(comment): + @<Finish line, |goto switch|@>@; +case new_line+car_ret: @<Finish line, emit a \.{\\par}@>@;@+break; +case mid_line+left_brace: incr(align_state);@+break; +case skip_blanks+left_brace: case new_line+left_brace: {@+ + state=mid_line;incr(align_state); + } @+break; +case mid_line+right_brace: decr(align_state);@+break; +case skip_blanks+right_brace: case new_line+right_brace: {@+ + state=mid_line;decr(align_state); + } @+break; +add_delims_to(case skip_blanks): add_delims_to(case new_line): state=mid_line;@+break; + +@ When a character of type |spacer| gets through, its character code is +changed to $\.{"\ "}=040$. This means that the ASCII codes for tab and space, +and for the space inserted at the end of a line, will +be treated alike when macro parameters are being matched. We do this +since such characters are indistinguishable on most computer terminal displays. + +@<Finish line, emit a space@>= +{@+loc=limit+1;cur_cmd=spacer;cur_chr=' '; +} + +@ The following code is performed only when |cur_cmd==spacer|. + +@<Enter |skip_blanks| state, emit a space@>= +{@+state=skip_blanks;cur_chr=' '; +} + +@ @<Finish line, |goto switch|@>= +{@+loc=limit+1;goto get_cur_chr; +} + +@ @<Finish line, emit a \.{\\par}@>= +{@+loc=limit+1;cur_cs=par_loc;cur_cmd=eq_type(cur_cs); +cur_chr=equiv(cur_cs); +if (cur_cmd >= outer_call) check_outer_validity(); +} + +@ Notice that a code like \.{\^\^8} becomes \.x if not followed by a hex digit. + +@d is_hex(A) (((A >= '0')&&(A <= '9'))||((A >= 'a')&&(A <= 'f'))) +@d hex_to_cur_chr + if (c <= '9') cur_chr=c-'0';@+else cur_chr=c-'a'+10; + if (cc <= '9') cur_chr=16*cur_chr+cc-'0'; + else cur_chr=16*cur_chr+cc-'a'+10 + +@<If this |sup_mark| starts an expanded character...@>= +{@+if (cur_chr==buffer[loc]) if (loc < limit) + {@+c=buffer[loc+1];@+if (c < 0200) /*yes we have an expanded char*/ + {@+loc=loc+2; + if (is_hex(c)) if (loc <= limit) + {@+cc=buffer[loc];@+if (is_hex(cc)) + {@+incr(loc);hex_to_cur_chr;goto reswitch; + } + } + if (c < 0100) cur_chr=c+0100;@+else cur_chr=c-0100; + goto reswitch; + } + } +state=mid_line; +} + +@ @<Process an active-character...@>= +{@+cur_cs=cur_chr+active_base; +cur_cmd=eq_type(cur_cs);cur_chr=equiv(cur_cs);state=mid_line; +if (cur_cmd >= outer_call) check_outer_validity(); +} + +@ Control sequence names are scanned only when they appear in some line of +a file; once they have been scanned the first time, their |eqtb| location +serves as a unique identification, so \TeX\ doesn't need to refer to the +original name any more except when it prints the equivalent in symbolic form. + +The program that scans a control sequence has been written carefully +in order to avoid the blowups that might otherwise occur if a malicious +user tried something like `\.{\\catcode\'15=0}'. The algorithm might +look at |buffer[limit+1]|, but it never looks at |buffer[limit+2]|. + +If expanded characters like `\.{\^\^A}' or `\.{\^\^df}' +appear in or just following +a control sequence name, they are converted to single characters in the +buffer and the process is repeated, slowly but surely. + +@<Scan a control...@>= +{@+if (loc > limit) cur_cs=null_cs; /*|state| is irrelevant in this case*/ +else{@+start_cs: k=loc;cur_chr=buffer[k];cat=cat_code(cur_chr); + incr(k); + if (cat==letter) state=skip_blanks; + else if (cat==spacer) state=skip_blanks; + else state=mid_line; + if ((cat==letter)&&(k <= limit)) + @<Scan ahead in the buffer until finding a nonletter; if an expanded code is encountered, +reduce it and |goto start_cs|; otherwise if a multiletter control sequence is found, +adjust |cur_cs| and |loc|, and |goto found|@>@; + else@<If an expanded code is present, reduce it and |goto start_cs|@>; + cur_cs=single_base+buffer[loc];incr(loc); + } +found: cur_cmd=eq_type(cur_cs);cur_chr=equiv(cur_cs); +if (cur_cmd >= outer_call) check_outer_validity(); +} + +@ Whenever we reach the following piece of code, we will have +|cur_chr==buffer[k-1]| and |k <= limit+1| and |cat==cat_code(cur_chr)|. If an +expanded code like \.{\^\^A} or \.{\^\^df} appears in |buffer[(k-1)dotdot(k+1)]| +or |buffer[(k-1)dotdot(k+2)]|, we +will store the corresponding code in |buffer[k-1]| and shift the rest of +the buffer left two or three places. + +@<If an expanded...@>= +{@+if (buffer[k]==cur_chr) @+if (cat==sup_mark) @+if (k < limit) + {@+c=buffer[k+1];@+if (c < 0200) /*yes, one is indeed present*/ + {@+d=2; + if (is_hex(c)) @+if (k+2 <= limit) + {@+cc=buffer[k+2];@+if (is_hex(cc)) incr(d); + } + if (d > 2) + {@+hex_to_cur_chr;buffer[k-1]=cur_chr; + } + else if (c < 0100) buffer[k-1]=c+0100; + else buffer[k-1]=c-0100; + limit=limit-d;first=first-d; + while (k <= limit) + {@+buffer[k]=buffer[k+d];incr(k); + } + goto start_cs; + } + } +} + +@ @<Scan ahead in the buffer...@>= +{@+@/do@+{cur_chr=buffer[k];cat=cat_code(cur_chr);incr(k); +}@+ while (!((cat!=letter)||(k > limit))); +@<If an expanded...@>; +if (cat!=letter) decr(k); + /*now |k| points to first nonletter*/ +if (k > loc+1) /*multiletter control sequence has been scanned*/ + {@+cur_cs=id_lookup(loc, k-loc);loc=k;goto found; + } +} + +@ Let's consider now what happens when |get_next| is looking at a token list. + +@<Input from token list, |goto restart| if end of list or if a parameter needs to +be expanded@>= +if (loc!=null) /*list not exhausted*/ +@^inner loop@> + {@+t=info(loc);loc=link(loc); /*move to next*/ + if (t >= cs_token_flag) /*a control sequence token*/ + {@+cur_cs=t-cs_token_flag; + cur_cmd=eq_type(cur_cs);cur_chr=equiv(cur_cs); + if (cur_cmd >= outer_call) + if (cur_cmd==dont_expand) + @<Get the next token, suppressing expansion@>@; + else check_outer_validity(); + } + else{@+cur_cmd=t/0400;cur_chr=t%0400; + switch (cur_cmd) { + case left_brace: incr(align_state);@+break; + case right_brace: decr(align_state);@+break; + case out_param: @<Insert macro parameter and |goto restart|@>@; + default:do_nothing; + } + } + } +else{@+ /*we are done with this token list*/ + end_token_list();goto restart; /*resume previous level*/ + } + +@ The present point in the program is reached only when the |expand| +routine has inserted a special marker into the input. In this special +case, |info(loc)| is known to be a control sequence token, and |link(loc)==null|. + +@d no_expand_flag 257 /*this characterizes a special variant of |relax|*/ + +@<Get the next token, suppressing expansion@>= +{@+cur_cs=info(loc)-cs_token_flag;loc=null;@/ +cur_cmd=eq_type(cur_cs);cur_chr=equiv(cur_cs); +if (cur_cmd > max_command) + {@+cur_cmd=relax;cur_chr=no_expand_flag; + } +} + +@ @<Insert macro parameter...@>= +{@+begin_token_list(param_stack[param_start+cur_chr-1], parameter); +goto restart; +} + +@ All of the easy branches of |get_next| have now been taken care of. +There is one more branch. + +@d end_line_char_inactive (end_line_char < 0)||(end_line_char > 255) + +@<Move to next line of file, or |goto restart|...@>= +if (name > 17) @<Read next line of file into |buffer|, or |goto restart| if the file +has ended@>@; +else{@+if (!terminal_input) /*\.{\\read} line has ended*/ + {@+cur_cmd=0;cur_chr=0;return; + } + if (input_ptr > 0) /*text was inserted during error recovery*/ + {@+end_file_reading();goto restart; /*resume previous level*/ + } + if (selector < log_only) open_log_file(); + if (interaction > nonstop_mode) + {@+if (end_line_char_inactive) incr(limit); + if (limit==start) /*previous line was empty*/ + print_nl("(Please type a command or say `\\end')"); +@.Please type...@> + print_ln();first=start; + prompt_input("*"); /*input on-line into |buffer|*/ +@.*\relax@> + limit=last; + if (end_line_char_inactive) decr(limit); + else buffer[limit]=end_line_char; + first=limit+1; + loc=start; + } + else fatal_error("*** (job aborted, no legal \\end found)"); +@.job aborted@> + /*nonstop mode, which is intended for overnight batch processing, + never waits for on-line input*/ + } + +@ The global variable |force_eof| is normally |false|; it is set |true| +by an \.{\\endinput} command. + +@<Glob...@>= +static bool @!force_eof; /*should the next \.{\\input} be aborted early?*/ + +@ @<Read next line of file into |buffer|, or |goto restart| if the file has ended@>= +{@+incr(line);first=start; +if (!force_eof) + if (name <= 19) + {@+if (pseudo_input()) /*not end of file*/ + firm_up_the_line(); /*this sets |limit|*/ + else if ((every_eof!=null)&&!eof_seen[index]) + {@+limit=first-1;eof_seen[index]=true; /*fake one empty line*/ + begin_token_list(every_eof, every_eof_text);goto restart; + } + else force_eof=true; + } + else + {@+if (input_ln(&cur_file, true)) /*not end of file*/ + firm_up_the_line(); /*this sets |limit|*/ + else if ((every_eof!=null)&&!eof_seen[index]) + {@+limit=first-1;eof_seen[index]=true; /*fake one empty line*/ + begin_token_list(every_eof, every_eof_text);goto restart; + } + else force_eof=true; + } +if (force_eof) + {@+if (tracing_nesting > 0) + if ((grp_stack[in_open]!=cur_boundary)||@| + (if_stack[in_open]!=cond_ptr)) file_warning(); + /*give warning for some unfinished groups and/or conditionals*/ + if (name >= 19) + {@+print_char(')');decr(open_parens); + update_terminal; /*show user that file has been read*/ + } + force_eof=false; + end_file_reading(); /*resume previous level*/ + check_outer_validity();goto restart; + } +if (end_line_char_inactive) decr(limit); +else buffer[limit]=end_line_char; +first=limit+1;loc=start; /*ready to read*/ +} + +@ If the user has set the |pausing| parameter to some positive value, +and if nonstop mode has not been selected, each line of input is displayed +on the terminal and the transcript file, followed by `\.{=>}'. +\TeX\ waits for a response. If the response is simply |carriage_return|, the +line is accepted as it stands, otherwise the line typed is +used instead of the line in the file. + +@p static void firm_up_the_line(void) +{@+int k; /*an index into |buffer|*/ +limit=last; +if (pausing > 0) if (interaction > nonstop_mode) + {@+wake_up_terminal;print_ln(); + if (start < limit) for (k=start; k<=limit-1; k++) printn(buffer[k]); + first=limit;prompt_input("=>"); /*wait for user response*/ +@.=>@> + if (last > first) + {@+for (k=first; k<=last-1; k++) /*move line down in buffer*/ + buffer[k+start-first]=buffer[k]; + limit=start+last-first; + } + } +} + +@ Since |get_next| is used so frequently in \TeX, it is convenient +to define three related procedures that do a little more: + +\yskip\hang|get_token| not only sets |cur_cmd| and |cur_chr|, it +also sets |cur_tok|, a packed halfword version of the current token. + +\yskip\hang|get_x_token|, meaning ``get an expanded token,'' is like +|get_token|, but if the current token turns out to be a user-defined +control sequence (i.e., a macro call), or a conditional, +or something like \.{\\topmark} or \.{\\expandafter} or \.{\\csname}, +it is eliminated from the input by beginning the expansion of the macro +or the evaluation of the conditional. + +\yskip\hang|x_token| is like |get_x_token| except that it assumes that +|get_next| has already been called. + +\yskip\noindent +In fact, these three procedures account for almost every use of |get_next|. + +@ No new control sequences will be defined except during a call of +|get_token|, or when \.{\\csname} compresses a token list, because +|no_new_control_sequence| is always |true| at other times. + +@p static void get_token(void) /*sets |cur_cmd|, |cur_chr|, |cur_tok|*/ +{@+no_new_control_sequence=false;get_next();no_new_control_sequence=true; +@^inner loop@> +if (cur_cs==0) cur_tok=(cur_cmd*0400)+cur_chr; +else cur_tok=cs_token_flag+cur_cs; +} + +@* Expanding the next token. +Only a dozen or so command codes | > max_command| can possibly be returned by +|get_next|; in increasing order, they are |undefined_cs|, |expand_after|, +|no_expand|, |input|, |if_test|, |fi_or_else|, |cs_name|, |convert|, |the|, +|top_bot_mark|, |call|, |long_call|, |outer_call|, |long_outer_call|, and +|end_template|.{\emergencystretch=40pt\par} + +The |expand| subroutine is used when |cur_cmd > max_command|. It removes a +``call'' or a conditional or one of the other special operations just +listed. It follows that |expand| might invoke itself recursively. In all +cases, |expand| destroys the current token, but it sets things up so that +the next |get_next| will deliver the appropriate next token. The value of +|cur_tok| need not be known when |expand| is called. + +Since several of the basic scanning routines communicate via global variables, +their values are saved as local variables of |expand| so that +recursive calls don't invalidate them. +@^recursion@> + +@p @t\4@>@<Declare the procedure called |macro_call|@>@;@/ +@t\4@>@<Declare the procedure called |insert_relax|@>@;@/ +@t\4@>@<Declare \eTeX\ procedures for expanding@>@;@/ +static void pass_text(void); +static void start_input(void); +static void conditional(void); +static void get_x_token(void); +static void conv_toks(void); +static void ins_the_toks(void); +static void expand(void) +{@+ +halfword t; /*token that is being ``expanded after''*/ +pointer @!p, @!q, @!r; /*for list manipulation*/ +int @!j; /*index into |buffer|*/ +int @!cv_backup; /*to save the global quantity |cur_val|*/ +small_number @!cvl_backup, @!radix_backup, @!co_backup; + /*to save |cur_val_level|, etc.*/ +pointer @!backup_backup; /*to save |link(backup_head)|*/ +small_number @!save_scanner_status; /*temporary storage of |scanner_status|*/ +cv_backup=cur_val;cvl_backup=cur_val_level;radix_backup=radix; +co_backup=cur_order;backup_backup=link(backup_head); +reswitch: +if (cur_cmd < call) @<Expand a nonmacro@>@; +else if (cur_cmd < end_template) macro_call(); +else@<Insert a token containing |frozen_endv|@>; +cur_val=cv_backup;cur_val_level=cvl_backup;radix=radix_backup; +cur_order=co_backup;link(backup_head)=backup_backup; +} + +@ @<Expand a nonmacro@>= +{@+if (tracing_commands > 1) show_cur_cmd_chr(); +switch (cur_cmd) { +case top_bot_mark: @<Insert the \(a)appropriate mark text into the scanner@>@;@+break; +case expand_after: if (cur_chr==0) @<Expand the token after the next token@>@; + else@<Negate a boolean conditional and |goto reswitch|@>@;@+break; +case no_expand: @<Suppress expansion of the next token@>@;@+break; +case cs_name: @<Manufacture a control sequence name@>@;@+break; +case convert: conv_toks();@+break; /*this procedure is discussed in Part 27 below*/ +case the: ins_the_toks();@+break; /*this procedure is discussed in Part 27 below*/ +case if_test: conditional();@+break; /*this procedure is discussed in Part 28 below*/ +case fi_or_else: @<Terminate the current conditional and skip to \.{\\fi}@>@;@+break; +case input: @<Initiate or terminate input from a file@>;@+break; +default:@<Complain about an undefined macro@>@; +} +} + +@ It takes only a little shuffling to do what \TeX\ calls \.{\\expandafter}. + +@<Expand the token after...@>= +{@+get_token();t=cur_tok;get_token(); +if (cur_cmd > max_command) expand();@+else back_input(); +cur_tok=t;back_input(); +} + +@ The implementation of \.{\\noexpand} is a bit trickier, because it is +necessary to insert a special `|dont_expand|' marker into \TeX's reading +mechanism. This special marker is processed by |get_next|, but it does +not slow down the inner loop. + +Since \.{\\outer} macros might arise here, we must also +clear the |scanner_status| temporarily. + +@<Suppress expansion...@>= +{@+save_scanner_status=scanner_status;scanner_status=normal; +get_token();scanner_status=save_scanner_status;t=cur_tok; +back_input(); /*now |start| and |loc| point to the backed-up token |t|*/ +if (t >= cs_token_flag) + {@+p=get_avail();info(p)=cs_token_flag+frozen_dont_expand; + link(p)=loc;start=p;loc=p; + } +} + +@ @<Complain about an undefined macro@>= +{@+print_err("Undefined control sequence"); +@.Undefined control sequence@> +help5("The control sequence at the end of the top line",@/ +"of your error message was never \\def'ed. If you have",@/ +"misspelled it (e.g., `\\hobx'), type `I' and the correct",@/ +"spelling (e.g., `I\\hbox'). Otherwise just continue,",@/ +"and I'll forget about whatever was undefined."); +error(); +} + +@ The |expand| procedure and some other routines that construct token +lists find it convenient to use the following macros, which are valid only if +the variables |p| and |q| are reserved for token-list building. + +@d store_new_token(A) {@+q=get_avail();link(p)=q;info(q)=A; + p=q; /*|link(p)| is |null|*/ + } +@d fast_store_new_token(A) {@+fast_get_avail(q);link(p)=q;info(q)=A; + p=q; /*|link(p)| is |null|*/ + } + +@ @<Manufacture a control...@>= +{@+r=get_avail();p=r; /*head of the list of characters*/ +@/do@+{get_x_token(); +if (cur_cs==0) store_new_token(cur_tok); +}@+ while (!(cur_cs!=0)); +if (cur_cmd!=end_cs_name) @<Complain about missing \.{\\endcsname}@>; +@<Look up the characters of list |r| in the hash table, and set |cur_cs|@>; +flush_list(r); +if (eq_type(cur_cs)==undefined_cs) + {@+eq_define(cur_cs, relax, 256); /*N.B.: The |save_stack| might change*/ + } /*the control sequence will now match `\.{\\relax}'*/ +cur_tok=cur_cs+cs_token_flag;back_input(); +} + +@ @<Complain about missing \.{\\endcsname}@>= +{@+print_err("Missing ");print_esc("endcsname");print(" inserted"); +@.Missing \\endcsname...@> +help2("The control sequence marked <to be read again> should",@/ + "not appear between \\csname and \\endcsname."); +back_error(); +} + +@ @<Look up the characters of list |r| in the hash table...@>= +j=first;p=link(r); +while (p!=null) + {@+if (j >= max_buf_stack) + {@+max_buf_stack=j+1; + if (max_buf_stack==buf_size) + overflow("buffer size", buf_size); +@:TeX capacity exceeded buffer size}{\quad buffer size@> + } + buffer[j]=info(p)%0400;incr(j);p=link(p); + } +if (j==first) cur_cs=null_cs; /*the list is empty*/ +else if (j > first+1) + {@+no_new_control_sequence=false;cur_cs=id_lookup(first, j-first); + no_new_control_sequence=true; + } +else cur_cs=single_base+buffer[first] /*the list has length one*/ + +@ An |end_template| command is effectively changed to an |endv| command +by the following code. (The reason for this is discussed below; the +|frozen_end_template| at the end of the template has passed the +|check_outer_validity| test, so its mission of error detection has been +accomplished.) + +@<Insert a token containing |frozen_endv|@>= +{@+cur_tok=cs_token_flag+frozen_endv;back_input(); +} + +@ The processing of \.{\\input} involves the |start_input| subroutine, +which will be declared later; the processing of \.{\\endinput} is trivial. + +@<Put each...@>= +primitive("input", input, 0);@/ +@!@:input\_}{\.{\\input} primitive@> +primitive("endinput", input, 1);@/ +@!@:end\_input\_}{\.{\\endinput} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case input: if (chr_code==0) print_esc("input") + @/@<Cases of |input| for |print_cmd_chr|@>;@/ + else print_esc("endinput");@+break; + +@ @<Initiate or terminate input...@>= +if (cur_chr==1) force_eof=true +@/@<Cases for |input|@>;@/ +else if (name_in_progress) insert_relax(); +else start_input() + +@ Sometimes the expansion looks too far ahead, so we want to insert +a harmless \.{\\relax} into the user's input. + +@<Declare the procedure called |insert_relax|@>= +static void insert_relax(void) +{@+cur_tok=cs_token_flag+cur_cs;back_input(); +cur_tok=cs_token_flag+frozen_relax;back_input();token_type=inserted; +} + +@ Here is a recursive procedure that is \TeX's usual way to get the +next token of input. It has been slightly optimized to take account of +common cases. + +@p static void get_x_token(void) /*sets |cur_cmd|, |cur_chr|, |cur_tok|, + and expands macros*/ +{@+ +restart: get_next(); +@^inner loop@> +if (cur_cmd <= max_command) goto done; +if (cur_cmd >= call) + if (cur_cmd < end_template) macro_call(); + else{@+cur_cs=frozen_endv;cur_cmd=endv; + goto done; /*|cur_chr==null_list|*/ + } +else expand(); +goto restart; +done: if (cur_cs==0) cur_tok=(cur_cmd*0400)+cur_chr; +else cur_tok=cs_token_flag+cur_cs; +} + +@ The |get_x_token| procedure is equivalent to two consecutive +procedure calls: |get_next;x_token|. + +@p static void x_token(void) /*|get_x_token| without the initial |get_next|*/ +{@+while (cur_cmd > max_command) + {@+expand(); + get_next(); + } +if (cur_cs==0) cur_tok=(cur_cmd*0400)+cur_chr; +else cur_tok=cs_token_flag+cur_cs; +} + +@ A control sequence that has been \.{\\def}'ed by the user is expanded by +\TeX's |macro_call| procedure. + +Before we get into the details of |macro_call|, however, let's consider the +treatment of primitives like \.{\\topmark}, since they are essentially +macros without parameters. The token lists for such marks are kept in a +global array of five pointers; we refer to the individual entries of this +array by symbolic names |top_mark|, etc. The value of |top_mark| is either +|null| or a pointer to the reference count of a token list. + +@d top_mark_code 0 /*the mark in effect at the previous page break*/ +@d first_mark_code 1 /*the first mark between |top_mark| and |bot_mark|*/ +@d bot_mark_code 2 /*the mark in effect at the current page break*/ +@d split_first_mark_code 3 /*the first mark found by \.{\\vsplit}*/ +@d split_bot_mark_code 4 /*the last mark found by \.{\\vsplit}*/ +@d top_mark cur_mark[top_mark_code] +@d first_mark cur_mark[first_mark_code] +@d bot_mark cur_mark[bot_mark_code] +@d split_first_mark cur_mark[split_first_mark_code] +@d split_bot_mark cur_mark[split_bot_mark_code] + +@<Glob...@>= +pointer @!cur_mark0[split_bot_mark_code-top_mark_code+1], *const @!cur_mark = @!cur_mark0-top_mark_code; + /*token lists for marks*/ + +@ @<Set init...@>= +top_mark=null;first_mark=null;bot_mark=null; +split_first_mark=null;split_bot_mark=null; + +@ @<Put each...@>= +primitive("topmark", top_bot_mark, top_mark_code); +@!@:top\_mark\_}{\.{\\topmark} primitive@> +primitive("firstmark", top_bot_mark, first_mark_code); +@!@:first\_mark\_}{\.{\\firstmark} primitive@> +primitive("botmark", top_bot_mark, bot_mark_code); +@!@:bot\_mark\_}{\.{\\botmark} primitive@> +primitive("splitfirstmark", top_bot_mark, split_first_mark_code); +@!@:split\_first\_mark\_}{\.{\\splitfirstmark} primitive@> +primitive("splitbotmark", top_bot_mark, split_bot_mark_code); +@!@:split\_bot\_mark\_}{\.{\\splitbotmark} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case top_bot_mark: switch (chr_code) { + case first_mark_code: print_esc("firstmark");@+break; + case bot_mark_code: print_esc("botmark");@+break; + case split_first_mark_code: print_esc("splitfirstmark");@+break; + case split_bot_mark_code: print_esc("splitbotmark");@+break; + default:print_esc("topmark"); + } @+break; + +@ The following code is activated when |cur_cmd==top_bot_mark| and +when |cur_chr| is a code like |top_mark_code|. + +@<Insert the \(a)appropriate mark text into the scanner@>= +{@+if (cur_mark[cur_chr]!=null) + begin_token_list(cur_mark[cur_chr], mark_text); +} + +@ Now let's consider |macro_call| itself, which is invoked when \TeX\ is +scanning a control sequence whose |cur_cmd| is either |call|, |long_call|, +|outer_call|, or |long_outer_call|. The control sequence definition +appears in the token list whose reference count is in location |cur_chr| +of |mem|. + +The global variable |long_state| will be set to |call| or to |long_call|, +depending on whether or not the control sequence disallows \.{\\par} +in its parameters. The |get_next| routine will set |long_state| to +|outer_call| and emit \.{\\par}, if a file ends or if an \.{\\outer} +control sequence occurs in the midst of an argument. + +@<Glob...@>= +static int @!long_state; /*governs the acceptance of \.{\\par}*/ + +@ The parameters, if any, must be scanned before the macro is expanded. +Parameters are token lists without reference counts. They are placed on +an auxiliary stack called |pstack| while they are being scanned, since +the |param_stack| may be losing entries during the matching process. +(Note that |param_stack| can't be gaining entries, since |macro_call| is +the only routine that puts anything onto |param_stack|, and it +is not recursive.) + +@<Glob...@>= +static pointer @!pstack[9]; /*arguments supplied to a macro*/ + +@ After parameter scanning is complete, the parameters are moved to the +|param_stack|. Then the macro body is fed to the scanner; in other words, +|macro_call| places the defined text of the control sequence at the +top of\/ \TeX's input stack, so that |get_next| will proceed to read it +next. + +The global variable |cur_cs| contains the |eqtb| address of the control sequence +being expanded, when |macro_call| begins. If this control sequence has not been +declared \.{\\long}, i.e., if its command code in the |eq_type| field is +not |long_call| or |long_outer_call|, its parameters are not allowed to contain +the control sequence \.{\\par}. If an illegal \.{\\par} appears, the macro +call is aborted, and the \.{\\par} will be rescanned. + +@<Declare the procedure called |macro_call|@>= +static void macro_call(void) /*invokes a user-defined control sequence*/ +{@+ +pointer r; /*current node in the macro's token list*/ +pointer @!p; /*current node in parameter token list being built*/ +pointer @!q; /*new node being put into the token list*/ +pointer @!s; /*backup pointer for parameter matching*/ +pointer @!t; /*cycle pointer for backup recovery*/ +pointer @!u, @!v; /*auxiliary pointers for backup recovery*/ +pointer @!rbrace_ptr; /*one step before the last |right_brace| token*/ +small_number @!n; /*the number of parameters scanned*/ +halfword @!unbalance; /*unmatched left braces in current parameter*/ +int @!m; /*the number of tokens or groups (usually)*/ +pointer @!ref_count; /*start of the token list*/ +small_number @!save_scanner_status; /*|scanner_status| upon entry*/ +pointer @!save_warning_index; /*|warning_index| upon entry*/ +ASCII_code @!match_chr; /*character used in parameter*/ +save_scanner_status=scanner_status;save_warning_index=warning_index; +warning_index=cur_cs;ref_count=cur_chr;r=link(ref_count);n=0; +if (tracing_macros > 0) @<Show the text of the macro being expanded@>; +if (info(r)==protected_token) r=link(r); +if (info(r)!=end_match_token) + @<Scan the parameters and make |link(r)| point to the macro body; but |return| if +an illegal \.{\\par} is detected@>; +@<Feed the macro body and its parameters to the scanner@>; +end: scanner_status=save_scanner_status;warning_index=save_warning_index; +} + +@ Before we put a new token list on the input stack, it is wise to clean off +all token lists that have recently been depleted. Then a user macro that ends +with a call to itself will not require unbounded stack space. + +@<Feed the macro body and its parameters to the scanner@>= +while ((state==token_list)&&(loc==null)&&(token_type!=v_template)) + end_token_list(); /*conserve stack space*/ +begin_token_list(ref_count, macro);name=warning_index;loc=link(r); +if (n > 0) + {@+if (param_ptr+n > max_param_stack) + {@+max_param_stack=param_ptr+n; + if (max_param_stack > param_size) + overflow("parameter stack size", param_size); +@:TeX capacity exceeded parameter stack size}{\quad parameter stack size@> + } + for (m=0; m<=n-1; m++) param_stack[param_ptr+m]=pstack[m]; + param_ptr=param_ptr+n; + } + +@ At this point, the reader will find it advisable to review the explanation +of token list format that was presented earlier, since many aspects of that +format are of importance chiefly in the |macro_call| routine. + +The token list might begin with a string of compulsory tokens before the +first |match| or |end_match|. In that case the macro name is supposed to be +followed by those tokens; the following program will set |s==null| to +represent this restriction. Otherwise |s| will be set to the first token of +a string that will delimit the next parameter. + +@<Scan the parameters and make |link(r)| point to the macro body...@>= +{@+scanner_status=matching;unbalance=0; +long_state=eq_type(cur_cs); +if (long_state >= outer_call) long_state=long_state-2; +@/do@+{link(temp_head)=null; +if ((info(r) > match_token+255)||(info(r) < match_token)) s=null; +else{@+match_chr=info(r)-match_token;s=link(r);r=s; + p=temp_head;m=0; + } +@<Scan a parameter until its delimiter string has been found; or, if |s=null|, simply +scan the delimiter string@>;@/ + /*now |info(r)| is a token whose command code is either |match| or |end_match|*/ +}@+ while (!(info(r)==end_match_token)); +} + +@ If |info(r)| is a |match| or |end_match| command, it cannot be equal to +any token found by |get_token|. Therefore an undelimited parameter---i.e., +a |match| that is immediately followed by |match| or |end_match|---will +always fail the test `|cur_tok==info(r)|' in the following algorithm. + +@<Scan a parameter until its delimiter string has been found; or,...@>= +resume: get_token(); /*set |cur_tok| to the next token of input*/ +if (cur_tok==info(r)) + @<Advance \(r)|r|; |goto found| if the parameter delimiter has been fully matched, +otherwise |goto continue|@>; +@<Contribute the recently matched tokens to the current parameter, and |goto continue| +if a partial match is still in effect; but abort if |s=null|@>; +if (cur_tok==par_token) if (long_state!=long_call) + @<Report a runaway argument and abort@>; +if (cur_tok < right_brace_limit) + if (cur_tok < left_brace_limit) + @<Contribute an entire group to the current parameter@>@; + else@<Report an extra right brace and |goto continue|@>@; +else@<Store the current token, but |goto continue| if it is a blank space that would +become an undelimited parameter@>; +incr(m); +if (info(r) > end_match_token) goto resume; +if (info(r) < match_token) goto resume; +found: if (s!=null) @<Tidy up the parameter just scanned, and tuck it away@>@; + +@ @<Store the current token, but |goto continue| if it is...@>= +{@+if (cur_tok==space_token) + if (info(r) <= end_match_token) + if (info(r) >= match_token) goto resume; +store_new_token(cur_tok); +} + +@ A slightly subtle point arises here: When the parameter delimiter ends +with `\.{\#\{}', the token list will have a left brace both before and +after the |end_match|\kern-.4pt. Only one of these should affect the +|align_state|, but both will be scanned, so we must make a correction. + +@<Advance \(r)|r|; |goto found| if the parameter delimiter has been fully...@>= +{@+r=link(r); +if ((info(r) >= match_token)&&(info(r) <= end_match_token)) + {@+if (cur_tok < left_brace_limit) decr(align_state); + goto found; + } +else goto resume; +} + +@ @<Report an extra right brace and |goto continue|@>= +{@+back_input();print_err("Argument of ");sprint_cs(warning_index); +@.Argument of \\x has...@> +print(" has an extra }"); +help6("I've run across a `}' that doesn't seem to match anything.",@/ + "For example, `\\def\\a#1{...}' and `\\a}' would produce",@/ + "this error. If you simply proceed now, the `\\par' that",@/ + "I've just inserted will cause me to report a runaway",@/ + "argument that might be the root of the problem. But if",@/ + "your `}' was spurious, just type `2' and it will go away."); +incr(align_state);long_state=call;cur_tok=par_token;ins_error(); +goto resume; +} /*a white lie; the \.{\\par} won't always trigger a runaway*/ + +@ If |long_state==outer_call|, a runaway argument has already been reported. + +@<Report a runaway argument and abort@>= +{@+if (long_state==call) + {@+runaway();print_err("Paragraph ended before "); +@.Paragraph ended before...@> + sprint_cs(warning_index);print(" was complete"); + help3("I suspect you've forgotten a `}', causing me to apply this",@/ + "control sequence to too much text. How can we recover?",@/ + "My plan is to forget the whole thing and hope for the best."); + back_error(); + } +pstack[n]=link(temp_head);align_state=align_state-unbalance; +for (m=0; m<=n; m++) flush_list(pstack[m]); +goto end; +} + +@ When the following code becomes active, we have matched tokens from |s| to +the predecessor of |r|, and we have found that |cur_tok!=info(r)|. An +interesting situation now presents itself: If the parameter is to be +delimited by a string such as `\.{ab}', and if we have scanned `\.{aa}', +we want to contribute one `\.a' to the current parameter and resume +looking for a `\.b'. The program must account for such partial matches and +for others that can be quite complex. But most of the time we have |s==r| +and nothing needs to be done. + +Incidentally, it is possible for \.{\\par} tokens to sneak in to certain +parameters of non-\.{\\long} macros. For example, consider a case like +`\.{\\def\\a\#1\\par!\{...\}}' where the first \.{\\par} is not followed +by an exclamation point. In such situations it does not seem appropriate +to prohibit the \.{\\par}, so \TeX\ keeps quiet about this bending of +the rules. + +@<Contribute the recently matched tokens to the current parameter...@>= +if (s!=r) + if (s==null) @<Report an improper use of the macro and abort@>@; + else{@+t=s; + @/do@+{store_new_token(info(t));incr(m);u=link(t);v=s; + loop@+{@+if (u==r) + if (cur_tok!=info(v)) goto done; + else{@+r=link(v);goto resume; + } + if (info(u)!=info(v)) goto done; + u=link(u);v=link(v); + } + done: t=link(t); + }@+ while (!(t==r)); + r=s; /*at this point, no tokens are recently matched*/ + } + +@ @<Report an improper use...@>= +{@+print_err("Use of ");sprint_cs(warning_index); +@.Use of x doesn't match...@> +print(" doesn't match its definition"); +help4("If you say, e.g., `\\def\\a1{...}', then you must always",@/ + "put `1' after `\\a', since control sequence names are",@/ + "made up of letters only. The macro here has not been",@/ + "followed by the required stuff, so I'm ignoring it."); +error();goto end; +} + +@ @<Contribute an entire group to the current parameter@>= +{@+unbalance=1; +@^inner loop@> +loop@+{@+fast_store_new_token(cur_tok);get_token(); + if (cur_tok==par_token) if (long_state!=long_call) + @<Report a runaway argument and abort@>; + if (cur_tok < right_brace_limit) + if (cur_tok < left_brace_limit) incr(unbalance); + else{@+decr(unbalance); + if (unbalance==0) goto done1; + } + } +done1: rbrace_ptr=p;store_new_token(cur_tok); +} + +@ If the parameter consists of a single group enclosed in braces, we must +strip off the enclosing braces. That's why |rbrace_ptr| was introduced. + +@<Tidy up the parameter just scanned, and tuck it away@>= +{@+if ((m==1)&&(info(p) < right_brace_limit)&&(p!=temp_head)) + {@+link(rbrace_ptr)=null;free_avail(p); + p=link(temp_head);pstack[n]=link(p);free_avail(p); + } +else pstack[n]=link(temp_head); +incr(n); +if (tracing_macros > 0) + {@+begin_diagnostic();print_nl("");printn(match_chr);print_int(n); + print("<-");show_token_list(pstack[n-1], null, 1000); + end_diagnostic(false); + } +} + +@ @<Show the text of the macro being expanded@>= +{@+begin_diagnostic();print_ln();print_cs(warning_index); +token_show(ref_count);end_diagnostic(false); +} + +@* Basic scanning subroutines. +Let's turn now to some procedures that \TeX\ calls upon frequently to digest +certain kinds of patterns in the input. Most of these are quite simple; +some are quite elaborate. Almost all of the routines call |get_x_token|, +which can cause them to be invoked recursively. +@^stomach@> +@^recursion@> + +@ The |scan_left_brace| routine is called when a left brace is supposed to be +the next non-blank token. (The term ``left brace'' means, more precisely, +a character whose catcode is |left_brace|.) \TeX\ allows \.{\\relax} to +appear before the |left_brace|. + +@p void scan_left_brace(void) /*reads a mandatory |left_brace|*/ +{@+@<Get the next non-blank non-relax non-call token@>; +if (cur_cmd!=left_brace) + {@+print_err("Missing { inserted"); +@.Missing \{ inserted@> + help4("A left brace was mandatory here, so I've put one in.",@/ + "You might want to delete and/or insert some corrections",@/ + "so that I will find a matching right brace soon.",@/ + "(If you're confused by all this, try typing `I}' now.)"); + back_error();cur_tok=left_brace_token+'{';cur_cmd=left_brace; + cur_chr='{';incr(align_state); + } +} + +@ @<Get the next non-blank non-relax non-call token@>= +@/do@+{get_x_token(); +}@+ while (!((cur_cmd!=spacer)&&(cur_cmd!=relax))) + +@ The |scan_optional_equals| routine looks for an optional `\.=' sign preceded +by optional spaces; `\.{\\relax}' is not ignored here. + +@p static void scan_optional_equals(void) +{@+@<Get the next non-blank non-call token@>; +if (cur_tok!=other_token+'=') back_input(); +} + +@ @<Get the next non-blank non-call token@>= +@/do@+{get_x_token(); +}@+ while (!(cur_cmd!=spacer)) + +@ In case you are getting bored, here is a slightly less trivial routine: +Given a string of lowercase letters, like `\.{pt}' or `\.{plus}' or +`\.{width}', the |scan_keyword| routine checks to see whether the next +tokens of input match this string. The match must be exact, except that +uppercase letters will match their lowercase counterparts; uppercase +equivalents are determined by subtracting |'a'-'A'|, rather than using the +|uc_code| table, since \TeX\ uses this routine only for its own limited +set of keywords. + +If a match is found, the characters are effectively removed from the input +and |true| is returned. Otherwise |false| is returned, and the input +is left essentially unchanged (except for the fact that some macros +may have been expanded, etc.). +@^inner loop@> + +@p static bool scan_keyword(char *@!s) /*look for a given string*/ +{@+ +pointer p; /*tail of the backup list*/ +pointer @!q; /*new node being added to the token list via |store_new_token|*/ +p=backup_head;link(p)=null; +while (*s!=0) + {@+get_x_token(); /*recursion is possible here*/ +@^recursion@> + if ((cur_cs==0)&&@| + ((cur_chr==so(*s))||(cur_chr==so(*s)-'a'+'A'))) + {@+store_new_token(cur_tok);incr(s); + } + else if ((cur_cmd!=spacer)||(p!=backup_head)) + {@+back_input(); + if (p!=backup_head) back_list(link(backup_head)); + return false; + } + } +flush_list(link(backup_head));return true; +} + +@ Here is a procedure that sounds an alarm when mu and non-mu units +are being switched. + +@p static void mu_error(void) +{@+print_err("Incompatible glue units"); +@.Incompatible glue units@> +help1("I'm going to assume that 1mu=1pt when they're mixed."); +error(); +} + +@ The next routine `|scan_something_internal|' is used to fetch internal +numeric quantities like `\.{\\hsize}', and also to handle the `\.{\\the}' +when expanding constructions like `\.{\\the\\toks0}' and +`\.{\\the\\baselineskip}'. Soon we will be considering the |scan_int| +procedure, which calls |scan_something_internal|; on the other hand, +|scan_something_internal| also calls |scan_int|, for constructions like +`\.{\\catcode\`\\\$}' or `\.{\\fontdimen} \.3 \.{\\ff}'. So we +have to declare |scan_int| as a |forward| procedure. A few other +procedures are also declared at this point. + +@p static void scan_int(void); /*scans an integer value*/ +@t\4\4@>@<Declare procedures that scan restricted classes of integers@>@; +@t\4\4@>@<Declare \eTeX\ procedures for scanning@>@; +@t\4\4@>@<Declare procedures that scan font-related stuff@>@; + +@ \TeX\ doesn't know exactly what to expect when |scan_something_internal| +begins. For example, an integer or dimension or glue value could occur +immediately after `\.{\\hskip}'; and one can even say \.{\\the} with +respect to token lists in constructions like +`\.{\\xdef\\o\{\\the\\output\}}'. On the other hand, only integers are +allowed after a construction like `\.{\\count}'. To handle the various +possibilities, |scan_something_internal| has a |level| parameter, which +tells the ``highest'' kind of quantity that |scan_something_internal| is +allowed to produce. Six levels are distinguished, namely |int_val|, +|dimen_val|, |glue_val|, |mu_val|, |ident_val|, and |tok_val|. + +The output of |scan_something_internal| (and of the other routines +|scan_int|, |scan_dimen|, and |scan_glue| below) is put into the global +variable |cur_val|, and its level is put into |cur_val_level|. The highest +values of |cur_val_level| are special: |mu_val| is used only when +|cur_val| points to something in a ``muskip'' register, or to one of the +three parameters \.{\\thinmuskip}, \.{\\medmuskip}, \.{\\thickmuskip}; +|ident_val| is used only when |cur_val| points to a font identifier; +|tok_val| is used only when |cur_val| points to |null| or to the reference +count of a token list. The last two cases are allowed only when +|scan_something_internal| is called with |level==tok_val|. + +If the output is glue, |cur_val| will point to a glue specification, and +the reference count of that glue will have been updated to reflect this +reference; if the output is a nonempty token list, |cur_val| will point to +its reference count, but in this case the count will not have been updated. +Otherwise |cur_val| will contain the integer or scaled value in question. + +@d int_val 0 /*integer values*/ +@d dimen_val 1 /*dimension values*/ +@d glue_val 2 /*glue specifications*/ +@d mu_val 3 /*math glue specifications*/ +@d ident_val 4 /*font identifier*/ +@d tok_val 5 /*token lists*/ +@d has_factor (cur_hfactor!=0 || cur_vfactor!=0) + +@<Glob...@>= +static int @!cur_val, @!cur_hfactor, @!cur_vfactor; /*value returned by numeric scanners*/ +static int @!cur_val_level; /*the ``level'' of this value*/ + +@ The hash table is initialized with `\.{\\count}', `\.{\\dimen}', `\.{\\skip}', +and `\.{\\muskip}' all having |internal_register| as their command code; they are +distinguished by the |chr_code|, which is either |int_val|, |dimen_val|, +|glue_val|, or |mu_val| more than |mem_bot| (dynamic variable-size nodes +cannot have these values) + +@<Put each...@>= +primitive("count", internal_register, mem_bot+int_val); +@!@:count\_}{\.{\\count} primitive@> +primitive("dimen", internal_register, mem_bot+dimen_val); +@!@:dimen\_}{\.{\\dimen} primitive@> +primitive("skip", internal_register, mem_bot+glue_val); +@!@:skip\_}{\.{\\skip} primitive@> +primitive("muskip", internal_register, mem_bot+mu_val); +@!@:mu\_skip\_}{\.{\\muskip} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case internal_register: @<Cases of |register| for |print_cmd_chr|@>@;@+break; + +@ OK, we're ready for |scan_something_internal| itself. A second parameter, +|negative|, is set |true| if the value that is found should be negated. +It is assumed that |cur_cmd| and |cur_chr| represent the first token of +the internal quantity to be scanned; an error will be signalled if +|cur_cmd < min_internal| or |cur_cmd > max_internal|. + +@d scanned_result(A, B) @+{@+cur_val=A;cur_val_level=B;@+} + +@p static void scan_something_internal(small_number @!level, bool @!negative) + /*fetch an internal parameter*/ +{@+ +halfword m; /*|chr_code| part of the operand token*/ +pointer @!q, @!r; /*general purpose indices*/ +pointer @!tx; /*effective tail node*/ +four_quarters @!i; /*character info*/ +int @!p; /*index into |nest|*/ +m=cur_chr; +switch (cur_cmd) { +case def_code: @<Fetch a character code from some table@>@;@+break; +case toks_register: case assign_toks: case def_family: case set_font: case def_font: @<Fetch +a token list or font identifier, provided that |level=tok_val|@>@;@+break; +case assign_int: scanned_result(eqtb[m].i, int_val)@;@+break; +case assign_dimen: + scanned_result(eqtb[m].sc, dimen_val); + if (m>=dimen_base)@/ + { cur_hfactor=hfactor_eqtb[m].sc;@+ + cur_vfactor=vfactor_eqtb[m].sc;@+ + } + else + cur_hfactor=cur_vfactor=0;@/ + @+break; +case assign_glue: scanned_result(equiv(m), glue_val)@;@+break; +case assign_mu_glue: scanned_result(equiv(m), mu_val)@;@+break; +case set_aux: @<Fetch the |space_factor| or the |prev_depth|@>@;@+break; +case set_prev_graf: @<Fetch the |prev_graf|@>@;@+break; +case set_page_int: @<Fetch the |dead_cycles| or the |insert_penalties|@>@;@+break; +case set_page_dimen: @<Fetch something on the |page_so_far|@>@;@+break; +case set_shape: @<Fetch the |par_shape| size@>@;@+break; +case set_box_dimen: @<Fetch a box dimension@>@;@+break; +case char_given: case math_given: scanned_result(cur_chr, int_val)@;@+break; +case assign_font_dimen: @<Fetch a font dimension@>@;@+break; +case assign_font_int: @<Fetch a font integer@>@;@+break; +case internal_register: @<Fetch a register@>@;@+break; +case last_item: @<Fetch an item in the current node, if appropriate@>@;@+break; +default:@<Complain that \.{\\the} can't do this; give zero result@>@; +} @/ +while (cur_val_level > level) @<Convert \(c)|cur_val| to a lower level@>; +@<Fix the reference count, if any, and negate |cur_val| if |negative|@>; +} + +@ @<Fetch a character code from some table@>= +{@+scan_char_num(); +if (m==math_code_base) scanned_result(ho(math_code(cur_val)), int_val)@; +else if (m < math_code_base) scanned_result(equiv(m+cur_val), int_val)@; +else scanned_result(eqtb[m+cur_val].i, int_val); +} + +@ @<Fetch a token list...@>= +if (level!=tok_val) + {@+print_err("Missing number, treated as zero"); +@.Missing number...@> + help3("A number should have been here; I inserted `0'.",@/ + "(If you can't figure out why I needed to see a number,",@/ + "look up `weird error' in the index to The TeXbook.)"); +@:TeXbook}{\sl The \TeX book@> + back_error();scanned_result(0, dimen_val); + } +else if (cur_cmd <= assign_toks) + {@+if (cur_cmd < assign_toks) /*|cur_cmd==toks_register|*/ + if (m==mem_bot) + {@+scan_register_num(); + if (cur_val < 256) cur_val=equiv(toks_base+cur_val); + else{@+find_sa_element(tok_val, cur_val, false); + if (cur_ptr==null) cur_val=null; + else cur_val=sa_ptr(cur_ptr); + } + } + else cur_val=sa_ptr(m); + else cur_val=equiv(m); + cur_val_level=tok_val; + } +else{@+back_input();scan_font_ident(); + scanned_result(font_id_base+cur_val, ident_val); + } + +@ Users refer to `\.{\\the\\spacefactor}' only in horizontal +mode, and to `\.{\\the\\prevdepth}' only in vertical mode; so we put the +associated mode in the modifier part of the |set_aux| command. +The |set_page_int| command has modifier 0 or 1, for `\.{\\deadcycles}' and +`\.{\\insertpenalties}', respectively. The |set_box_dimen| command is +modified by either |width_offset|, |height_offset|, or |depth_offset|. +And the |last_item| command is modified by either |int_val|, |dimen_val|, +|glue_val|, |input_line_no_code|, or |badness_code|. +\eTeX\ inserts |last_node_type_code| after |glue_val| and adds +the codes for its extensions: |eTeX_version_code|, \dots\ . + +@d last_node_type_code (glue_val+1) /*code for \.{\\lastnodetype}*/ +@d input_line_no_code (glue_val+2) /*code for \.{\\inputlineno}*/ +@d badness_code (input_line_no_code+1) /*code for \.{\\badness}*/ +@# +@d eTeX_int (badness_code+1) /*first of \eTeX\ codes for integers*/ +@d eTeX_dim (eTeX_int+8) /*first of \eTeX\ codes for dimensions*/ +@d eTeX_glue (eTeX_dim+9) /*first of \eTeX\ codes for glue*/ +@d eTeX_mu (eTeX_glue+1) /*first of \eTeX\ codes for muglue*/ +@d eTeX_expr (eTeX_mu+1) /*first of \eTeX\ codes for expressions*/ + +@<Put each...@>= +primitive("spacefactor", set_aux, hmode); +@!@:space\_factor\_}{\.{\\spacefactor} primitive@> +primitive("prevdepth", set_aux, vmode);@/ +@!@:prev\_depth\_}{\.{\\prevdepth} primitive@> +primitive("deadcycles", set_page_int, 0); +@!@:dead\_cycles\_}{\.{\\deadcycles} primitive@> +primitive("insertpenalties", set_page_int, 1); +@!@:insert\_penalties\_}{\.{\\insertpenalties} primitive@> +primitive("wd", set_box_dimen, width_offset); +@!@:wd\_}{\.{\\wd} primitive@> +primitive("ht", set_box_dimen, height_offset); +@!@:ht\_}{\.{\\ht} primitive@> +primitive("dp", set_box_dimen, depth_offset); +@!@:dp\_}{\.{\\dp} primitive@> +primitive("lastpenalty", last_item, int_val); +@!@:last\_penalty\_}{\.{\\lastpenalty} primitive@> +primitive("lastkern", last_item, dimen_val); +@!@:last\_kern\_}{\.{\\lastkern} primitive@> +primitive("lastskip", last_item, glue_val); +@!@:last\_skip\_}{\.{\\lastskip} primitive@> +primitive("inputlineno", last_item, input_line_no_code); +@!@:input\_line\_no\_}{\.{\\inputlineno} primitive@> +primitive("badness", last_item, badness_code); +@!@:badness\_}{\.{\\badness} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case set_aux: if (chr_code==vmode) print_esc("prevdepth"); +@+else print_esc("spacefactor");@+break; +case set_page_int: if (chr_code==0) print_esc("deadcycles") +@/@<Cases of |set_page_int| for |print_cmd_chr|@>;@/ +@+else print_esc("insertpenalties");@+break; +case set_box_dimen: if (chr_code==width_offset) print_esc("wd"); +else if (chr_code==height_offset) print_esc("ht"); +else print_esc("dp");@+break; +case last_item: switch (chr_code) { + case int_val: print_esc("lastpenalty");@+break; + case dimen_val: print_esc("lastkern");@+break; + case glue_val: print_esc("lastskip");@+break; + case input_line_no_code: print_esc("inputlineno");@+break; + @/@<Cases of |last_item| for |print_cmd_chr|@>@/ + default:print_esc("badness"); + } @+break; + +@ @<Fetch the |space_factor| or the |prev_depth|@>= +if (abs(mode)!=m) + {@+print_err("Improper ");print_cmd_chr(set_aux, m); +@.Improper \\spacefactor@> +@.Improper \\prevdepth@> + help4("You can refer to \\spacefactor only in horizontal mode;",@/ + "you can refer to \\prevdepth only in vertical mode; and",@/ + "neither of these is meaningful inside \\write. So",@/ + "I'm forgetting what you said and using zero instead."); + error(); + if (level!=tok_val) scanned_result(0, dimen_val)@; + else scanned_result(0, int_val); + } +else if (m==vmode) scanned_result(prev_depth, dimen_val)@; +else scanned_result(space_factor, int_val) + +@ @<Fetch the |dead_cycles| or the |insert_penalties|@>= +{@+if (m==0) cur_val=dead_cycles +@/@<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>;@/ +else cur_val=insert_penalties; +cur_val_level=int_val; +} + +@ @<Fetch a box dimension@>= +{@+scan_register_num();fetch_box(q); +if (q==null) cur_val=0;@+else cur_val=mem[q+m].sc; +cur_val_level=dimen_val; +} + +@ Inside an \.{\\output} routine, a user may wish to look at the page totals +that were present at the moment when output was triggered. + +@d max_dimen 07777777777 /*$2^{30}-1$*/ + +@<Fetch something on the |page_so_far|@>= +{@+if ((page_contents==empty)&&(!output_active)) + if (m==0) cur_val=max_dimen;@+else cur_val=0; +else cur_val=page_so_far[m]; +cur_val_level=dimen_val; +} + +@ @<Fetch the |prev_graf|@>= +if (mode==0) scanned_result(0, int_val)@; /*|prev_graf==0| within \.{\\write}*/ +else{@+nest[nest_ptr]=cur_list;p=nest_ptr; + while (abs(nest[p].mode_field)!=vmode) decr(p); + scanned_result(nest[p].pg_field, int_val); + } + +@ @<Fetch the |par_shape| size@>= +{@+if (m > par_shape_loc) @<Fetch a penalties array element@>@; +else if (par_shape_ptr==null) cur_val=0; +else cur_val=info(par_shape_ptr); +cur_val_level=int_val; +} + +@ Here is where \.{\\lastpenalty}, \.{\\lastkern}, \.{\\lastskip}, and +\.{\\lastnodetype} are +implemented. The reference count for \.{\\lastskip} will be updated later. + +We also handle \.{\\inputlineno} and \.{\\badness} here, because they are +legal in similar contexts. + +@<Fetch an item in the current node...@>= +if (m >= input_line_no_code) + if (m >= eTeX_glue) @<Process an expression and |return|@>@; + else if (m >= eTeX_dim) + {@+switch (m) { + @/@<Cases for fetching a dimension value@>@/ + } /*there are no other cases*/ + cur_val_level=dimen_val; + } + else{@+switch (m) { + case input_line_no_code: cur_val=line;@+break; + case badness_code: cur_val=last_badness;@+break; + @/@<Cases for fetching an integer value@>@/ + } /*there are no other cases*/ + cur_val_level=int_val; + } +else{@+if (cur_chr==glue_val) cur_val=zero_glue;@+else cur_val=0; + cur_val_level=cur_chr; + if (!is_char_node(tail)&&(mode!=0)) + switch (cur_chr) { + case int_val: if (type(tail)==penalty_node) cur_val=penalty(tail);@+break; + case dimen_val: if (type(tail)==kern_node) cur_val=width(tail);@+break; + case glue_val: if (type(tail)==glue_node) + {@+cur_val=glue_ptr(tail); + if (subtype(tail)==mu_glue) cur_val_level=mu_val; + } + } /*there are no other cases*/ + else if ((mode==vmode)&&(tail==head)) + switch (cur_chr) { + case int_val: cur_val=last_penalty;@+break; + case dimen_val: cur_val=last_kern;@+break; + case glue_val: if (last_glue!=max_halfword) cur_val=last_glue;@+break; + case last_node_type_code: cur_val=last_node_type; + } /*there are no other cases*/ + } + +@ @<Fetch a font dimension@>= +{@+find_font_dimen(false);font_info[fmem_ptr].sc=0; +scanned_result(font_info[cur_val].sc, dimen_val); +} + +@ @<Fetch a font integer@>= +{@+scan_font_ident(); +if (m==0) scanned_result(hyphen_char[cur_val], int_val)@; +else scanned_result(skew_char[cur_val], int_val); +} + +@ @<Fetch a register@>= +{@+if ((m < mem_bot)||(m > lo_mem_stat_max)) + {@+cur_val_level=sa_type(m); + if (cur_val_level < glue_val) cur_val=sa_int(m); + else cur_val=sa_ptr(m); + } +else{@+scan_register_num();cur_val_level=m-mem_bot; + if (cur_val > 255) + {@+find_sa_element(cur_val_level, cur_val, false); + if (cur_ptr==null) + if (cur_val_level < glue_val) cur_val=0; + else cur_val=zero_glue; + else if (cur_val_level < glue_val) cur_val=sa_int(cur_ptr); + else cur_val=sa_ptr(cur_ptr); + } + else + switch (cur_val_level) { +case int_val: cur_val=count(cur_val);@+break; +case dimen_val: + cur_hfactor=dimen_hfactor(cur_val); + cur_vfactor=dimen_vfactor(cur_val); + cur_val=dimen(cur_val);@+break; +case glue_val: cur_val=skip(cur_val);@+break; +case mu_val: cur_val=mu_skip(cur_val); +} /*there are no other cases*/ + } +} + +@ @<Complain that \.{\\the} can't do this; give zero result@>= +{@+print_err("You can't use `");print_cmd_chr(cur_cmd, cur_chr); +@.You can't use x after ...@> +print("' after ");print_esc("the"); +help1("I'm forgetting what you said and using zero instead."); +error(); +if (level!=tok_val) scanned_result(0, dimen_val)@; +else scanned_result(0, int_val); +} + +@ When a |glue_val| changes to a |dimen_val|, we use the width component +of the glue; there is no need to decrease the reference count, since it +has not yet been increased. When a |dimen_val| changes to an |int_val|, +we use scaled points so that the value doesn't actually change. And when a +|mu_val| changes to a |glue_val|, the value doesn't change either. + +@<Convert \(c)|cur_val| to a lower level@>= +{@+if (cur_val_level==glue_val) cur_val=width(cur_val); +else if (cur_val_level==mu_val) mu_error(); +decr(cur_val_level); +} + +@ If |cur_val| points to a glue specification at this point, the reference +count for the glue does not yet include the reference by |cur_val|. +If |negative| is |true|, |cur_val_level| is known to be | <= mu_val|. + +@<Fix the reference count, if any,...@>= +if (negative) + if (cur_val_level >= glue_val) + {@+cur_val=new_spec(cur_val); + @<Negate all three glue components of |cur_val|@>; + } + else {@+ negate(cur_val);@+ negate(cur_hfactor); @+negate(cur_vfactor); @+} +else if ((cur_val_level >= glue_val)&&(cur_val_level <= mu_val)) + add_glue_ref(cur_val) + +@ @<Negate all three...@>= +{@+negate(width(cur_val)); +negate(stretch(cur_val)); +negate(shrink(cur_val)); +} + +@ Our next goal is to write the |scan_int| procedure, which scans anything that +\TeX\ treats as an integer. But first we might as well look at some simple +applications of |scan_int| that have already been made inside of +|scan_something_internal|. + +@ @<Declare procedures that scan restricted classes of integers@>= +static void scan_eight_bit_int(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > 255)) + {@+print_err("Bad register code"); +@.Bad register code@> + help2("A register number must be between 0 and 255.",@/ + "I changed this one to zero.");int_error(cur_val);cur_val=0; + } +} + +@ @<Declare procedures that scan restricted classes of integers@>= +static void scan_char_num(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > 255)) + {@+print_err("Bad character code"); +@.Bad character code@> + help2("A character number must be between 0 and 255.",@/ + "I changed this one to zero.");int_error(cur_val);cur_val=0; + } +} + +@ While we're at it, we might as well deal with similar routines that +will be needed later. + +@<Declare procedures that scan restricted classes of integers@>= +static void scan_four_bit_int(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > 15)) + {@+print_err("Bad number"); +@.Bad number@> + help2("Since I expected to read a number between 0 and 15,",@/ + "I changed this one to zero.");int_error(cur_val);cur_val=0; + } +} + +@ @<Declare procedures that scan restricted classes of integers@>= +static void scan_fifteen_bit_int(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > 077777)) + {@+print_err("Bad mathchar"); +@.Bad mathchar@> + help2("A mathchar number must be between 0 and 32767.",@/ + "I changed this one to zero.");int_error(cur_val);cur_val=0; + } +} + +@ @<Declare procedures that scan restricted classes of integers@>= +static void scan_twenty_seven_bit_int(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > 0777777777)) + {@+print_err("Bad delimiter code"); +@.Bad delimiter code@> + help2("A numeric delimiter code must be between 0 and 2^{27}-1.",@/ + "I changed this one to zero.");int_error(cur_val);cur_val=0; + } +} + +@ An integer number can be preceded by any number of spaces and `\.+' or +`\.-' signs. Then comes either a decimal constant (i.e., radix 10), an +octal constant (i.e., radix 8, preceded by~\.\'), a hexadecimal constant +(radix 16, preceded by~\."), an alphabetic constant (preceded by~\.\`), or +an internal variable. After scanning is complete, +|cur_val| will contain the answer, which must be at most +$2^{31}-1=2147483647$ in absolute value. The value of |radix| is set to +10, 8, or 16 in the cases of decimal, octal, or hexadecimal constants, +otherwise |radix| is set to zero. An optional space follows a constant. + +@d octal_token (other_token+'\'') /*apostrophe, indicates an octal constant*/ +@d hex_token (other_token+'"') /*double quote, indicates a hex constant*/ +@d alpha_token (other_token+'`') /*reverse apostrophe, precedes alpha constants*/ +@d point_token (other_token+'.') /*decimal point*/ +@d continental_point_token (other_token+',') /*decimal point, Eurostyle*/ + +@<Glob...@>= +static small_number @!radix; /*|scan_int| sets this to 8, 10, 16, or zero*/ + +@ We initialize the following global variables just in case |expand| +comes into action before any of the basic scanning routines has assigned +them a value. + +@<Set init...@>= +cur_val=0;cur_val_level=int_val;radix=0;cur_order=normal; + +@ The |scan_int| routine is used also to scan the integer part of a +fraction; for example, the `\.3' in `\.{3.14159}' will be found by +|scan_int|. The |scan_dimen| routine assumes that |cur_tok==point_token| +after the integer part of such a fraction has been scanned by |scan_int|, +and that the decimal point has been backed up to be scanned again. + +@p static void scan_int(void) /*sets |cur_val| to an integer*/ +{@+ +bool negative; /*should the answer be negated?*/ +int @!m; /*|@t$2^{31}$@>/radix|, the threshold of danger*/ +small_number @!d; /*the digit just scanned*/ +bool @!vacuous; /*have no digits appeared?*/ +bool @!OK_so_far; /*has an error message been issued?*/ +radix=0;OK_so_far=true;@/ +@<Get the next non-blank non-sign token; set |negative| appropriately@>; +if (cur_tok==alpha_token) @<Scan an alphabetic character code into |cur_val|@>@; +else if ((cur_cmd >= min_internal)&&(cur_cmd <= max_internal)) + scan_something_internal(int_val, false); +else@<Scan a numeric constant@>; +if (negative) negate(cur_val); +} + +@ @<Get the next non-blank non-sign token...@>= +negative=false; +@/do@+{@<Get the next non-blank non-call token@>; +if (cur_tok==other_token+'-') + {@+negative=!negative;cur_tok=other_token+'+'; + } +}@+ while (!(cur_tok!=other_token+'+')) + +@ A space is ignored after an alphabetic character constant, so that +such constants behave like numeric ones. + +@<Scan an alphabetic character code into |cur_val|@>= +{@+get_token(); /*suppress macro expansion*/ +if (cur_tok < cs_token_flag) + {@+cur_val=cur_chr; + if (cur_cmd <= right_brace) + if (cur_cmd==right_brace) incr(align_state); + else decr(align_state); + } +else if (cur_tok < cs_token_flag+single_base) + cur_val=cur_tok-cs_token_flag-active_base; +else cur_val=cur_tok-cs_token_flag-single_base; +if (cur_val > 255) + {@+print_err("Improper alphabetic constant"); +@.Improper alphabetic constant@> + help2("A one-character control sequence belongs after a ` mark.",@/ + "So I'm essentially inserting \\0 here."); + cur_val='0';back_error(); + } +else@<Scan an optional space@>; +} + +@ @<Scan an optional space@>= +{@+get_x_token();if (cur_cmd!=spacer) back_input(); +} + +@ @<Scan a numeric constant@>= +{@+radix=10;m=214748364; +if (cur_tok==octal_token) + {@+radix=8;m=02000000000;get_x_token(); + } +else if (cur_tok==hex_token) + {@+radix=16;m=01000000000;get_x_token(); + } +vacuous=true;cur_val=0;@/ +@<Accumulate the constant until |cur_tok| is not a suitable digit@>; +if (vacuous) @<Express astonishment that no number was here@>@; +else if (cur_cmd!=spacer) back_input(); +} + +@ @d infinity 017777777777 /*the largest positive value that \TeX\ knows*/ +@d zero_token (other_token+'0') /*zero, the smallest digit*/ +@d A_token (letter_token+'A') /*the smallest special hex digit*/ +@d other_A_token (other_token+'A') /*special hex digit of type |other_char|*/ + +@<Accumulate the constant...@>= +loop@+{@+if ((cur_tok < zero_token+radix)&&(cur_tok >= zero_token)&& + (cur_tok <= zero_token+9)) d=cur_tok-zero_token; + else if (radix==16) + if ((cur_tok <= A_token+5)&&(cur_tok >= A_token)) d=cur_tok-A_token+10; + else if ((cur_tok <= other_A_token+5)&&(cur_tok >= other_A_token)) + d=cur_tok-other_A_token+10; + else goto done; + else goto done; + vacuous=false; + if ((cur_val >= m)&&((cur_val > m)||(d > 7)||(radix!=10))) + {@+if (OK_so_far) + {@+print_err("Number too big"); +@.Number too big@> + help2("I can only go up to 2147483647='17777777777=\"7FFFFFFF,",@/ + "so I'm using that number instead of yours."); + error();cur_val=infinity;OK_so_far=false; + } + } + else cur_val=cur_val*radix+d; + get_x_token(); + } +done: + +@ @<Express astonishment...@>= +{@+print_err("Missing number, treated as zero"); +@.Missing number...@> +help3("A number should have been here; I inserted `0'.",@/ + "(If you can't figure out why I needed to see a number,",@/ + "look up `weird error' in the index to The TeXbook.)"); +@:TeXbook}{\sl The \TeX book@> +back_error(); +} + +@ The |scan_dimen| routine is similar to |scan_int|, but it sets |cur_val| to +a |scaled| value, i.e., an integral number of sp. One of its main tasks +is therefore to interpret the abbreviations for various kinds of units and +to convert measurements to scaled points. + +There are three parameters: |mu| is |true| if the finite units must be +`\.{mu}', while |mu| is |false| if `\.{mu}' units are disallowed; +|inf| is |true| if the infinite units `\.{fil}', `\.{fill}', `\.{filll}' +are permitted; and |shortcut| is |true| if |cur_val| already contains +an integer and only the units need to be considered. + +The order of infinity that was found in the case of infinite glue is returned +in the global variable |cur_order|. + +@<Glob...@>= +static glue_ord @!cur_order; /*order of infinity found by |scan_dimen|*/ + +@ Constructions like `\.{-\'77 pt}' are legal dimensions, so |scan_dimen| +may begin with |scan_int|. This explains why it is convenient to use +|scan_int| also for the integer part of a decimal fraction. + +Several branches of |scan_dimen| work with |cur_val| as an integer and +with an auxiliary fraction |f|, so that the actual quantity of interest is +$|cur_val|+|f|/2^{16}$. At the end of the routine, this ``unpacked'' +representation is put into the single word |cur_val|, which suddenly +switches significance from |int| to |scaled|. + +@d scan_normal_dimen scan_dimen(false, false, false) + +@p static void scan_dimen(bool @!mu, bool @!inf, bool @!shortcut) + /*sets |cur_val| to a dimension*/ +{@+ +bool negative; /*should the answer be negated?*/ +int @!f; /*numerator of a fraction whose denominator is $2^{16}$*/ +@<Local variables for dimension calculations@>@; +f=0;arith_error=false;cur_order=normal;negative=false; +cur_hfactor=cur_vfactor=0; +if (!shortcut) + {@+@<Get the next non-blank non-sign...@>; + if ((cur_cmd >= min_internal)&&(cur_cmd <= max_internal)) + @<Fetch an internal dimension and |goto attach_sign|, or fetch an internal integer@>@; + else{@+back_input(); + if (cur_tok==continental_point_token) cur_tok=point_token; + if (cur_tok!=point_token) scan_int(); + else{@+radix=10;cur_val=0; + } + if (cur_tok==continental_point_token) cur_tok=point_token; + if ((radix==10)&&(cur_tok==point_token)) @<Scan decimal fraction@>; + } + } +if (cur_val < 0) /*in this case |f==0|*/ + {@+negative=!negative;negate(cur_val); + } +@<Scan units and set |cur_val| to $x\cdot(|cur_val|+f/2^{16})$, where there are |x| +sp per unit; |goto attach_sign| if the units are internal@>; +@<Scan an optional space@>; +attach_sign: +if (arith_error||(abs(cur_val) >= 010000000000)|| +(abs(cur_hfactor) >= 010000000000) || (abs(cur_vfactor) >= 010000000000)) + @<Report that this dimension is out of range@>; +if (negative) @/{@+ negate(cur_val);@+ negate(cur_hfactor); @+negate(cur_vfactor);@+ } +} + +@ @<Fetch an internal dimension and |goto attach_sign|...@>= +if (mu) + {@+scan_something_internal(mu_val, false); + @<Coerce glue to a dimension@>; + if (cur_val_level==mu_val) goto attach_sign; + if (cur_val_level!=int_val) mu_error(); + } +else{@+scan_something_internal(dimen_val, false); + if (cur_val_level==dimen_val) goto attach_sign; + } + +@ @<Local variables for dimension calculations@>= +int @!num, @!denom; /*conversion ratio for the scanned units*/ +int @!k, @!kk; /*number of digits in a decimal fraction*/ +pointer @!p, @!q; /*top of decimal digit stack*/ +scaled @!v; /*an internal dimension*/ +int @!save_cur_val; /*temporary storage of |cur_val|*/ + +@ The following code is executed when |scan_something_internal| was +called asking for |mu_val|, when we really wanted a ``mudimen'' instead +of ``muglue.'' + +@<Coerce glue to a dimension@>= +if (cur_val_level >= glue_val) + {@+v=width(cur_val);delete_glue_ref(cur_val);cur_val=v; + } + +@ When the following code is executed, we have |cur_tok==point_token|, but this +token has been backed up using |back_input|; we must first discard it. + +It turns out that a decimal point all by itself is equivalent to `\.{0.0}'. +Let's hope people don't use that fact. + +@<Scan decimal fraction@>= +{@+k=0;p=null;get_token(); /*|point_token| is being re-scanned*/ +loop@+{@+get_x_token(); + if ((cur_tok > zero_token+9)||(cur_tok < zero_token)) goto done1; + if (k < 17) /*digits for |k >= 17| cannot affect the result*/ + {@+q=get_avail();link(q)=p;info(q)=cur_tok-zero_token; + p=q;incr(k); + } + } +done1: for (kk=k; kk>=1; kk--) + {@+dig[kk-1]=info(p);q=p;p=link(p);free_avail(q); + } +f=round_decimals(k); +if (cur_cmd!=spacer) back_input(); +} + +@ Now comes the harder part: At this point in the program, |cur_val| is a +nonnegative integer and $f/2^{16}$ is a nonnegative fraction less than 1; +we want to multiply the sum of these two quantities by the appropriate +factor, based on the specified units, in order to produce a |scaled| +result, and we want to do the calculation with fixed point arithmetic that +does not overflow. + +@<Scan units and set |cur_val| to $x\cdot(|cur_val|+f/2^{16})$...@>= +if (inf) @<Scan for \(f)\.{fil} units; |goto attach_fraction| if found@>; +@<Scan for \(u)units that are internal dimensions; |goto attach_sign| with |cur_val| +set if found@>; +if (mu) @<Scan for \(m)\.{mu} units and |goto attach_fraction|@>; +if (scan_keyword("true")) @<Adjust \(f)for the magnification ratio@>; +@.true@> +if (scan_keyword("pt")) goto attach_fraction; /*the easy case*/ +@.pt@> +@<Scan for \(a)all other units and adjust |cur_val| and |f| accordingly; |goto done| +in the case of scaled points@>; +attach_fraction: if (cur_val >= 040000) arith_error=true; +else cur_val=cur_val*unity+f; +done: + +@ A specification like `\.{filllll}' or `\.{fill L L L}' will lead to two +error messages (one for each additional keyword \.{"l"}). + +@<Scan for \(f)\.{fil} units...@>= +if (scan_keyword("fil")) +@.fil@> + {@+cur_order=fil; + while (scan_keyword("l")) + {@+if (cur_order==filll) + {@+print_err("Illegal unit of measure ("); +@.Illegal unit of measure@> + print("replaced by filll)"); + help1("I dddon't go any higher than filll.");error(); + } + else incr(cur_order); + } + goto attach_fraction; + } + +@ @<Scan for \(u)units that are internal dimensions...@>= +save_cur_val=cur_val; +if (has_factor) +{ print_err("Factor is not constant. Linear component ignored"); + cur_hfactor=cur_vfactor=0; +} +@<Get the next non-blank non-call...@>; +if ((cur_cmd < min_internal)||(cur_cmd > max_internal)) back_input(); +else{@+if (mu) + {@+scan_something_internal(mu_val, false);@<Coerce glue...@>; + if (cur_val_level!=mu_val) mu_error(); + } + else scan_something_internal(dimen_val, false); + v=cur_val;goto found; + } +if (mu) goto not_found; +if (scan_keyword("em")) v=(@<The em width for |cur_font|@>); +@.em@> +else if (scan_keyword("ex")) v=(@<The x-height for |cur_font|@>); +@.ex@> +else goto not_found; +@<Scan an optional space@>; +found: +if (has_factor) +{ cur_hfactor=nx_plus_y(save_cur_val, cur_hfactor, xn_over_d(cur_hfactor, f, unity)); + cur_vfactor=nx_plus_y(save_cur_val, cur_vfactor, xn_over_d(cur_vfactor, f, unity)); +} + cur_val=nx_plus_y(save_cur_val, v, xn_over_d(v, f, unity)); +goto attach_sign; +not_found: + +@ @<Scan for \(m)\.{mu} units and |goto attach_fraction|@>= +if (scan_keyword("mu")) goto attach_fraction; +@.mu@> +else{@+print_err("Illegal unit of measure (");print("mu inserted)"); +@.Illegal unit of measure@> + help4("The unit of measurement in math glue must be mu.",@/ + "To recover gracefully from this error, it's best to",@/ + "delete the erroneous units; e.g., type `2' to delete",@/ + "two letters. (See Chapter 27 of The TeXbook.)"); +@:TeXbook}{\sl The \TeX book@> + error();goto attach_fraction; + } + +@ @<Adjust \(f)for the magnification ratio@>= +{@+prepare_mag(); +if (mag!=1000) + {@+cur_val=xn_over_d(cur_val, 1000, mag); + f=(1000*f+0200000*rem)/mag; + cur_val=cur_val+(f/0200000);f=f%0200000; + } +} + +@ The necessary conversion factors can all be specified exactly as +fractions whose numerator and denominator sum to 32768 or less. +According to the definitions here, $\rm2660\,dd\approx1000.33297\,mm$; +this agrees well with the value $\rm1000.333\,mm$ cited by Bosshard +@^Bosshard, Hans Rudolf@> +in {\sl Technische Grundlagen zur Satzherstellung\/} (Bern, 1980). + +@d set_conversion(A, B) @+{@+num=A;denom=B;} + +@<Scan for \(a)all other units and adjust |cur_val| and |f|...@>= +if (scan_keyword("in")) set_conversion(7227, 100)@; +@.in@> +else if (scan_keyword("pc")) set_conversion(12, 1)@; +@.pc@> +else if (scan_keyword("cm")) set_conversion(7227, 254)@; +@.cm@> +else if (scan_keyword("mm")) set_conversion(7227, 2540)@; +@.mm@> +else if (scan_keyword("bp")) set_conversion(7227, 7200)@; +@.bp@> +else if (scan_keyword("dd")) set_conversion(1238, 1157)@; +@.dd@> +else if (scan_keyword("cc")) set_conversion(14856, 1157)@; +@.cc@> +else if (scan_keyword("sp")) goto done; +@.sp@> +else@<Complain about unknown unit and |goto done2|@>; +cur_val=xn_over_d(cur_val, num, denom); +f=(num*f+0200000*rem)/denom;@/ +cur_val=cur_val+(f/0200000);f=f%0200000; +done2: + +@ @<Complain about unknown unit...@>= +{@+print_err("Illegal unit of measure (");print("pt inserted)"); +@.Illegal unit of measure@> +help6("Dimensions can be in units of em, ex, in, pt, pc,",@/ + "cm, mm, dd, cc, bp, or sp; but yours is a new one!",@/ + "I'll assume that you meant to say pt, for printer's points.",@/ + "To recover gracefully from this error, it's best to",@/ + "delete the erroneous units; e.g., type `2' to delete",@/ + "two letters. (See Chapter 27 of The TeXbook.)"); +@:TeXbook}{\sl The \TeX book@> +error();goto done2; +} + + +@ @<Report that this dimension is out of range@>= +{@+print_err("Dimension too large"); +@.Dimension too large@> +help2("I can't work with sizes bigger than about 19 feet.",@/ + "Continue and I'll use the largest value I can.");@/ +error();cur_val=max_dimen;arith_error=false; +} + +@ The final member of \TeX's value-scanning trio is |scan_glue|, which +makes |cur_val| point to a glue specification. The reference count of that +glue spec will take account of the fact that |cur_val| is pointing to~it. + +The |level| parameter should be either |glue_val| or |mu_val|. + +Since |scan_dimen| was so much more complex than |scan_int|, we might expect +|scan_glue| to be even worse. But fortunately, it is very simple, since +most of the work has already been done. + +@p static void scan_glue(small_number @!level) + /*sets |cur_val| to a glue spec pointer*/ +{@+ +bool negative; /*should the answer be negated?*/ +pointer @!q; /*new glue specification*/ +bool @!mu; /*does |level==mu_val|?*/ +mu=(level==mu_val);@<Get the next non-blank non-sign...@>; +if ((cur_cmd >= min_internal)&&(cur_cmd <= max_internal)) + {@+scan_something_internal(level, negative); + if (cur_val_level >= glue_val) + {@+if (cur_val_level!=level) mu_error(); + return; + } + if (cur_val_level==int_val) scan_dimen(mu, false, true); + else if (level==mu_val) mu_error(); + } +else{@+back_input();scan_dimen(mu, false, false); + if (negative) { negate(cur_val); negate(cur_hfactor); negate(cur_vfactor);} + } +@<Create a new glue specification whose width is |cur_val|; scan for its stretch and +shrink components@>; +} +@# +@<Declare procedures needed for expressions@>@; + +@ @<Create a new glue specification whose width is |cur_val|...@>= +q=new_spec(zero_glue);width(q)=cur_val; +if (scan_keyword("plus")) +@.plus@> + {@+scan_dimen(mu, true, false); + stretch(q)=cur_val;stretch_order(q)=cur_order; + } +if (scan_keyword("minus")) +@.minus@> + {@+scan_dimen(mu, true, false); + shrink(q)=cur_val;shrink_order(q)=cur_order; + } +cur_val=q + +@ Here's a similar procedure that returns a pointer to a rule node. This +routine is called just after \TeX\ has seen \.{\\hrule} or \.{\\vrule}; +therefore |cur_cmd| will be either |hrule| or |vrule|. The idea is to store +the default rule dimensions in the node, then to override them if +`\.{height}' or `\.{width}' or `\.{depth}' specifications are +found (in any order). + +@d default_rule 26214 /*0.4\thinspace pt*/ + +@p static pointer scan_rule_spec(void) +{@+ +pointer q; /*the rule node being created*/ +q=new_rule(); /*|width|, |depth|, and |height| all equal |null_flag| now*/ +if (cur_cmd==vrule) width(q)=default_rule; +else{@+height(q)=default_rule;depth(q)=0; + } +reswitch: if (scan_keyword("width")) +@.width@> + {@+scan_normal_dimen;width(q)=cur_val;goto reswitch; + } +if (scan_keyword("height")) +@.height@> + {@+scan_normal_dimen;height(q)=cur_val;goto reswitch; + } +if (scan_keyword("depth")) +@.depth@> + {@+scan_normal_dimen;depth(q)=cur_val;goto reswitch; + } +return q; +} + +@* Building token lists. +The token lists for macros and for other things like \.{\\mark} and \.{\\output} +and \.{\\write} are produced by a procedure called |scan_toks|. + +Before we get into the details of |scan_toks|, let's consider a much +simpler task, that of converting the current string into a token list. +The |str_toks| function does this; it classifies spaces as type |spacer| +and everything else as type |other_char|. + +The token list created by |str_toks| begins at |link(temp_head)| and ends +at the value |p| that is returned. (If |p==temp_head|, the list is empty.) + +@p @t\4@>@<Declare \eTeX\ procedures for token lists@>@;@/ +static pointer str_toks(pool_pointer @!b) + /*changes the string |str_pool[b dotdot pool_ptr]| to a token list*/ +{@+pointer p; /*tail of the token list*/ +pointer @!q; /*new node being added to the token list via |store_new_token|*/ +halfword @!t; /*token being appended*/ +pool_pointer @!k; /*index into |str_pool|*/ +str_room(1); +p=temp_head;link(p)=null;k=b; +while (k < pool_ptr) + {@+t=so(str_pool[k]); + if (t==' ') t=space_token; + else t=other_token+t; + fast_store_new_token(t); + incr(k); + } +pool_ptr=b;return p; +} + +@ The main reason for wanting |str_toks| is the next function, +|the_toks|, which has similar input/output characteristics. + +This procedure is supposed to scan something like `\.{\\skip\\count12}', +i.e., whatever can follow `\.{\\the}', and it constructs a token list +containing something like `\.{-3.0pt minus 0.5fill}'. + +@p static pointer the_toks(void) +{@+ +int old_setting; /*holds |selector| setting*/ +pointer @!p, @!q, @!r; /*used for copying a token list*/ +pool_pointer @!b; /*base of temporary string*/ +small_number @!c; /*value of |cur_chr|*/ +@<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>;@/ +get_x_token();scan_something_internal(tok_val, false); +if (cur_val_level >= ident_val) @<Copy the token list@>@; +else{@+old_setting=selector;selector=new_string;b=pool_ptr; + switch (cur_val_level) { + case int_val: print_int(cur_val);@+break; + case dimen_val: {@+print_scaled(cur_val);print("pt"); + } @+break; + case glue_val: {@+print_spec(cur_val,"pt");delete_glue_ref(cur_val); + } @+break; + case mu_val: {@+print_spec(cur_val,"mu");delete_glue_ref(cur_val); + } + } /*there are no other cases*/ + selector=old_setting;return str_toks(b); + } +} + +@ @<Copy the token list@>= +{@+p=temp_head;link(p)=null; +if (cur_val_level==ident_val) store_new_token(cs_token_flag+cur_val)@; +else if (cur_val!=null) + {@+r=link(cur_val); /*do not copy the reference count*/ + while (r!=null) + {@+fast_store_new_token(info(r));r=link(r); + } + } +return p; +} + +@ Here's part of the |expand| subroutine that we are now ready to complete: + +@p static void ins_the_toks(void) +{@+link(garbage)=the_toks();ins_list(link(temp_head)); +} + +@ The primitives \.{\\number}, \.{\\romannumeral}, \.{\\string}, \.{\\meaning}, +\.{\\fontname}, and \.{\\jobname} are defined as follows. + +\eTeX\ adds \.{\\eTeXrevision} such that |job_name_code| remains last. + +@d number_code 0 /*command code for \.{\\number}*/ +@d roman_numeral_code 1 /*command code for \.{\\romannumeral}*/ +@d string_code 2 /*command code for \.{\\string}*/ +@d meaning_code 3 /*command code for \.{\\meaning}*/ +@d font_name_code 4 /*command code for \.{\\fontname}*/ +@d etex_convert_base 5 /*base for \eTeX's command codes*/ +@d eTeX_revision_code etex_convert_base /*command code for \.{\\eTeXrevision}*/ +@d etex_convert_codes (etex_convert_base+1) /*end of \eTeX's command codes*/ +@d job_name_code etex_convert_codes /*command code for \.{\\jobname}*/ + +@<Put each...@>= +primitive("number", convert, number_code);@/ +@!@:number\_}{\.{\\number} primitive@> +primitive("romannumeral", convert, roman_numeral_code);@/ +@!@:roman\_numeral\_}{\.{\\romannumeral} primitive@> +primitive("string", convert, string_code);@/ +@!@:string\_}{\.{\\string} primitive@> +primitive("meaning", convert, meaning_code);@/ +@!@:meaning\_}{\.{\\meaning} primitive@> +primitive("fontname", convert, font_name_code);@/ +@!@:font\_name\_}{\.{\\fontname} primitive@> +primitive("jobname", convert, job_name_code);@/ +@!@:job\_name\_}{\.{\\jobname} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case convert: switch (chr_code) { + case number_code: print_esc("number");@+break; + case roman_numeral_code: print_esc("romannumeral");@+break; + case string_code: print_esc("string");@+break; + case meaning_code: print_esc("meaning");@+break; + case font_name_code: print_esc("fontname");@+break; + case eTeX_revision_code: print_esc("eTeXrevision");@+break; + default:print_esc("jobname"); + } @+break; + +@ The procedure |conv_toks| uses |str_toks| to insert the token list +for |convert| functions into the scanner; `\.{\\outer}' control sequences +are allowed to follow `\.{\\string}' and `\.{\\meaning}'. + +@p static void conv_toks(void) +{@+int old_setting; /*holds |selector| setting*/ +int @!c; /*desired type of conversion*/ +small_number @!save_scanner_status; /*|scanner_status| upon entry*/ +pool_pointer @!b; /*base of temporary string*/ +c=cur_chr;@<Scan the argument for command |c|@>; +old_setting=selector;selector=new_string;b=pool_ptr; +@<Print the result of command |c|@>; +selector=old_setting;link(garbage)=str_toks(b);ins_list(link(temp_head)); +} + +@ @<Scan the argument for command |c|@>= +switch (c) { +case number_code: case roman_numeral_code: scan_int();@+break; +case string_code: case meaning_code: {@+save_scanner_status=scanner_status; + scanner_status=normal;get_token();scanner_status=save_scanner_status; + } @+break; +case font_name_code: scan_font_ident();@+break; +case eTeX_revision_code: do_nothing;@+break; +case job_name_code: if (job_name==0) open_log_file(); +} /*there are no other cases*/ + +@ @<Print the result of command |c|@>= +switch (c) { +case number_code: print_int(cur_val);@+break; +case roman_numeral_code: print_roman_int(cur_val);@+break; +case string_code: if (cur_cs!=0) sprint_cs(cur_cs); + else print_char(cur_chr);@+break; +case meaning_code: print_meaning();@+break; +case font_name_code: {@+printn(font_name[cur_val]); + if (font_size[cur_val]!=font_dsize[cur_val]) + {@+print(" at ");print_scaled(font_size[cur_val]); + print("pt"); + } + } @+break; +case eTeX_revision_code: print(eTeX_revision);@+break; +case job_name_code: printn(job_name); +} /*there are no other cases*/ + +@ Now we can't postpone the difficulties any longer; we must bravely tackle +|scan_toks|. This function returns a pointer to the tail of a new token +list, and it also makes |def_ref| point to the reference count at the +head of that list. + +There are two boolean parameters, |macro_def| and |xpand|. If |macro_def| +is true, the goal is to create the token list for a macro definition; +otherwise the goal is to create the token list for some other \TeX\ +primitive: \.{\\mark}, \.{\\output}, \.{\\everypar}, \.{\\lowercase}, +\.{\\uppercase}, \.{\\message}, \.{\\errmessage}, \.{\\write}, or +\.{\\special}. In the latter cases a left brace must be scanned next; this +left brace will not be part of the token list, nor will the matching right +brace that comes at the end. If |xpand| is false, the token list will +simply be copied from the input using |get_token|. Otherwise all expandable +tokens will be expanded until unexpandable tokens are left, except that +the results of expanding `\.{\\the}' are not expanded further. +If both |macro_def| and |xpand| are true, the expansion applies +only to the macro body (i.e., to the material following the first +|left_brace| character). + +The value of |cur_cs| when |scan_toks| begins should be the |eqtb| +address of the control sequence to display in ``runaway'' error +messages. + +@p static pointer scan_toks(bool @!macro_def, bool @!xpand) +{@+ +halfword t; /*token representing the highest parameter number*/ +halfword @!s; /*saved token*/ +pointer @!p; /*tail of the token list being built*/ +pointer @!q; /*new node being added to the token list via |store_new_token|*/ +halfword @!unbalance; /*number of unmatched left braces*/ +halfword @!hash_brace; /*possible `\.{\#\{}' token*/ +if (macro_def) scanner_status=defining; +@+else scanner_status=absorbing; +warning_index=cur_cs;def_ref=get_avail();token_ref_count(def_ref)=null; +p=def_ref;hash_brace=0;t=zero_token; +if (macro_def) @<Scan and build the parameter part of the macro definition@>@; +else scan_left_brace(); /*remove the compulsory left brace*/ +@<Scan and build the body of the token list; |goto found| when finished@>; +found: scanner_status=normal; +if (hash_brace!=0) store_new_token(hash_brace); +return p; +} + +@ @<Scan and build the parameter part...@>= +{@+loop{@+get_token(); /*set |cur_cmd|, |cur_chr|, |cur_tok|*/ + if (cur_tok < right_brace_limit) goto done1; + if (cur_cmd==mac_param) + @<If the next character is a parameter number, make |cur_tok| a |match| token; +but if it is a left brace, store `|left_brace|, |end_match|', set |hash_brace|, and +|goto done|@>; + store_new_token(cur_tok); + } +done1: store_new_token(end_match_token); +if (cur_cmd==right_brace) + @<Express shock at the missing left brace; |goto found|@>; +done: ;} + +@ @<Express shock...@>= +{@+print_err("Missing { inserted");incr(align_state); +@.Missing \{ inserted@> +help2("Where was the left brace? You said something like `\\def\\a}',",@/ + "which I'm going to interpret as `\\def\\a{}'.");error();goto found; +} + +@ @<If the next character is a parameter number...@>= +{@+s=match_token+cur_chr;get_token(); +if (cur_cmd==left_brace) + {@+hash_brace=cur_tok; + store_new_token(cur_tok);store_new_token(end_match_token); + goto done; + } +if (t==zero_token+9) + {@+print_err("You already have nine parameters"); +@.You already have nine...@> + help1("I'm going to ignore the # sign you just used.");error(); + } +else{@+incr(t); + if (cur_tok!=t) + {@+print_err("Parameters must be numbered consecutively"); +@.Parameters...consecutively@> + help2("I've inserted the digit you should have used after the #.",@/ + "Type `1' to delete what you did use.");back_error(); + } + cur_tok=s; + } +} + +@ @<Scan and build the body of the token list; |goto found| when finished@>= +unbalance=1; +loop@+{@+if (xpand) @<Expand the next part of the input@>@; + else get_token(); + if (cur_tok < right_brace_limit) + if (cur_cmd < right_brace) incr(unbalance); + else{@+decr(unbalance); + if (unbalance==0) goto found; + } + else if (cur_cmd==mac_param) + if (macro_def) @<Look for parameter number or \.{\#\#}@>; + store_new_token(cur_tok); + } + +@ Here we insert an entire token list created by |the_toks| without +expanding it further. + +@<Expand the next part of the input@>= +{@+loop{@+get_next(); + if (cur_cmd >= call) + if (info(link(cur_chr))==protected_token) + {@+cur_cmd=relax;cur_chr=no_expand_flag; + } + if (cur_cmd <= max_command) goto done2; + if (cur_cmd!=the) expand(); + else{@+q=the_toks(); + if (link(temp_head)!=null) + {@+link(p)=link(temp_head);p=q; + } + } + } +done2: x_token(); +} + +@ @<Look for parameter number...@>= +{@+s=cur_tok; +if (xpand) get_x_token();else get_token(); +if (cur_cmd!=mac_param) + if ((cur_tok <= zero_token)||(cur_tok > t)) + {@+print_err("Illegal parameter number in definition of "); +@.Illegal parameter number...@> + sprint_cs(warning_index); + help3("You meant to type ## instead of #, right?",@/ + "Or maybe a } was forgotten somewhere earlier, and things",@/ + "are all screwed up? I'm going to assume that you meant ##."); + back_error();cur_tok=s; + } + else cur_tok=out_param_token-'0'+cur_chr; +} + +@ Another way to create a token list is via the \.{\\read} command. The +sixteen files potentially usable for reading appear in the following +global variables. The value of |read_open[n]| will be |closed| if +stream number |n| has not been opened or if it has been fully read; +|just_open| if an \.{\\openin} but not a \.{\\read} has been done; +and |normal| if it is open and ready to read the next line. + +@d closed 2 /*not open, or at end of file*/ +@d just_open 1 /*newly opened, first line not yet read*/ + +@<Glob...@>= +static alpha_file @!read_file[16]; /*used for \.{\\read}*/ +static int8_t @!read_open[17]; /*state of |read_file[n]|*/ + +@ @<Set init...@>= +for (k=0; k<=16; k++) read_open[k]=closed; + +@ The |read_toks| procedure constructs a token list like that for any +macro definition, and makes |cur_val| point to it. Parameter |r| points +to the control sequence that will receive this token list. + +@p static void read_toks(int @!n, pointer @!r, halfword @!j) +{@+ +pointer p; /*tail of the token list*/ +pointer @!q; /*new node being added to the token list via |store_new_token|*/ +int @!s; /*saved value of |align_state|*/ +small_number @!m; /*stream number*/ +scanner_status=defining;warning_index=r; +def_ref=get_avail();token_ref_count(def_ref)=null; +p=def_ref; /*the reference count*/ +store_new_token(end_match_token); +if ((n < 0)||(n > 15)) m=16;@+else m=n; +s=align_state;align_state=1000000; /*disable tab marks, etc.*/ +@/do@+{@<Input and store tokens from the next line of the file@>; +}@+ while (!(align_state==1000000)); +cur_val=def_ref;scanner_status=normal;align_state=s; +} + +@ @<Input and store tokens from the next line of the file@>= +begin_file_reading();name=m+1; +if (read_open[m]==closed) @<Input for \.{\\read} from the terminal@>; +else if (read_open[m]==just_open) @<Input the first line of |read_file[m]|@>@; +else@<Input the next line of |read_file[m]|@>; +limit=last; +if (end_line_char_inactive) decr(limit); +else buffer[limit]=end_line_char; +first=limit+1;loc=start;state=new_line;@/ +@<Handle \.{\\readline} and |goto done|@>;@/ +loop@+{@+get_token(); + if (cur_tok==0) goto done; + /*|cur_cmd==cur_chr==0| will occur at the end of the line*/ + if (align_state < 1000000) /*unmatched `\.\}' aborts the line*/ + {@+@/do@+{get_token();}@+ while (!(cur_tok==0)); + align_state=1000000;goto done; + } + store_new_token(cur_tok); + } +done: end_file_reading() + +@ Here we input on-line into the |buffer| array, prompting the user explicitly +if |n >= 0|. The value of |n| is set negative so that additional prompts +will not be given in the case of multi-line input. + +@<Input for \.{\\read} from the terminal@>= +if (interaction > nonstop_mode) + if (n < 0) prompt_input("")@; + else{@+wake_up_terminal; + print_ln();sprint_cs(r);prompt_input("=");n=-1; + } +else fatal_error("*** (cannot \\read from terminal in nonstop modes)") +@.cannot \\read@> + +@ The first line of a file must be treated specially, since |input_ln| +must be told not to start with |get|. +@^system dependencies@> + +@<Input the first line of |read_file[m]|@>= +if (input_ln(&read_file[m], false)) read_open[m]=normal; +else{@+a_close(&read_file[m]);read_open[m]=closed; + } + +@ An empty line is appended at the end of a |read_file|. +@^empty line at end of file@> + +@<Input the next line of |read_file[m]|@>= +{@+if (!input_ln(&read_file[m], true)) + {@+a_close(&read_file[m]);read_open[m]=closed; + if (align_state!=1000000) + {@+runaway(); + print_err("File ended within ");print_esc("read"); +@.File ended within \\read@> + help1("This \\read has unbalanced braces."); + align_state=1000000;error(); + } + } +} + +@* Conditional processing. +We consider now the way \TeX\ handles various kinds of \.{\\if} commands. + +@d unless_code 32 /*amount added for `\.{\\unless}' prefix*/ +@# +@d if_char_code 0 /* `\.{\\if}' */ +@d if_cat_code 1 /* `\.{\\ifcat}' */ +@d if_int_code 2 /* `\.{\\ifnum}' */ +@d if_dim_code 3 /* `\.{\\ifdim}' */ +@d if_odd_code 4 /* `\.{\\ifodd}' */ +@d if_vmode_code 5 /* `\.{\\ifvmode}' */ +@d if_hmode_code 6 /* `\.{\\ifhmode}' */ +@d if_mmode_code 7 /* `\.{\\ifmmode}' */ +@d if_inner_code 8 /* `\.{\\ifinner}' */ +@d if_void_code 9 /* `\.{\\ifvoid}' */ +@d if_hbox_code 10 /* `\.{\\ifhbox}' */ +@d if_vbox_code 11 /* `\.{\\ifvbox}' */ +@d ifx_code 12 /* `\.{\\ifx}' */ +@d if_eof_code 13 /* `\.{\\ifeof}' */ +@d if_true_code 14 /* `\.{\\iftrue}' */ +@d if_false_code 15 /* `\.{\\iffalse}' */ +@d if_case_code 16 /* `\.{\\ifcase}' */ + +@<Put each...@>= +primitive("if", if_test, if_char_code); +@!@:if\_char\_}{\.{\\if} primitive@> +primitive("ifcat", if_test, if_cat_code); +@!@:if\_cat\_code\_}{\.{\\ifcat} primitive@> +primitive("ifnum", if_test, if_int_code); +@!@:if\_int\_}{\.{\\ifnum} primitive@> +primitive("ifdim", if_test, if_dim_code); +@!@:if\_dim\_}{\.{\\ifdim} primitive@> +primitive("ifodd", if_test, if_odd_code); +@!@:if\_odd\_}{\.{\\ifodd} primitive@> +primitive("ifvmode", if_test, if_vmode_code); +@!@:if\_vmode\_}{\.{\\ifvmode} primitive@> +primitive("ifhmode", if_test, if_hmode_code); +@!@:if\_hmode\_}{\.{\\ifhmode} primitive@> +primitive("ifmmode", if_test, if_mmode_code); +@!@:if\_mmode\_}{\.{\\ifmmode} primitive@> +primitive("ifinner", if_test, if_inner_code); +@!@:if\_inner\_}{\.{\\ifinner} primitive@> +primitive("ifvoid", if_test, if_void_code); +@!@:if\_void\_}{\.{\\ifvoid} primitive@> +primitive("ifhbox", if_test, if_hbox_code); +@!@:if\_hbox\_}{\.{\\ifhbox} primitive@> +primitive("ifvbox", if_test, if_vbox_code); +@!@:if\_vbox\_}{\.{\\ifvbox} primitive@> +primitive("ifx", if_test, ifx_code); +@!@:ifx\_}{\.{\\ifx} primitive@> +primitive("ifeof", if_test, if_eof_code); +@!@:if\_eof\_}{\.{\\ifeof} primitive@> +primitive("iftrue", if_test, if_true_code); +@!@:if\_true\_}{\.{\\iftrue} primitive@> +primitive("iffalse", if_test, if_false_code); +@!@:if\_false\_}{\.{\\iffalse} primitive@> +primitive("ifcase", if_test, if_case_code); +@!@:if\_case\_}{\.{\\ifcase} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case if_test: {@+if (chr_code >= unless_code) print_esc("unless"); +switch (chr_code%unless_code) { + case if_cat_code: print_esc("ifcat");@+break; + case if_int_code: print_esc("ifnum");@+break; + case if_dim_code: print_esc("ifdim");@+break; + case if_odd_code: print_esc("ifodd");@+break; + case if_vmode_code: print_esc("ifvmode");@+break; + case if_hmode_code: print_esc("ifhmode");@+break; + case if_mmode_code: print_esc("ifmmode");@+break; + case if_inner_code: print_esc("ifinner");@+break; + case if_void_code: print_esc("ifvoid");@+break; + case if_hbox_code: print_esc("ifhbox");@+break; + case if_vbox_code: print_esc("ifvbox");@+break; + case ifx_code: print_esc("ifx");@+break; + case if_eof_code: print_esc("ifeof");@+break; + case if_true_code: print_esc("iftrue");@+break; + case if_false_code: print_esc("iffalse");@+break; + case if_case_code: print_esc("ifcase");@+break; + @/@<Cases of |if_test| for |print_cmd_chr|@>@/ + default:print_esc("if"); + } +} @+break; + +@ Conditions can be inside conditions, and this nesting has a stack +that is independent of the |save_stack|. + +Four global variables represent the top of the condition stack: +|cond_ptr| points to pushed-down entries, if any; |if_limit| specifies +the largest code of a |fi_or_else| command that is syntactically legal; +|cur_if| is the name of the current type of conditional; and |if_line| +is the line number at which it began. + +If no conditions are currently in progress, the condition stack has the +special state |cond_ptr==null|, |if_limit==normal|, |cur_if==0|, |if_line==0|. +Otherwise |cond_ptr| points to a two-word node; the |type|, |subtype|, and +|link| fields of the first word contain |if_limit|, |cur_if|, and +|cond_ptr| at the next level, and the second word contains the +corresponding |if_line|. + +@d if_node_size 2 /*number of words in stack entry for conditionals*/ +@d if_line_field(A) mem[A+1].i +@d if_code 1 /*code for \.{\\if...} being evaluated*/ +@d fi_code 2 /*code for \.{\\fi}*/ +@d else_code 3 /*code for \.{\\else}*/ +@d or_code 4 /*code for \.{\\or}*/ + +@<Glob...@>= +static pointer @!cond_ptr; /*top of the condition stack*/ +static int @!if_limit; /*upper bound on |fi_or_else| codes*/ +static small_number @!cur_if; /*type of conditional being worked on*/ +static int @!if_line; /*line where that conditional began*/ + +@ @<Set init...@>= +cond_ptr=null;if_limit=normal;cur_if=0;if_line=0; + +@ @<Put each...@>= +primitive("fi", fi_or_else, fi_code); +@!@:fi\_}{\.{\\fi} primitive@> +text(frozen_fi)=text(cur_val);eqtb[frozen_fi]=eqtb[cur_val]; +primitive("or", fi_or_else, or_code); +@!@:or\_}{\.{\\or} primitive@> +primitive("else", fi_or_else, else_code); +@!@:else\_}{\.{\\else} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case fi_or_else: if (chr_code==fi_code) print_esc("fi"); + else if (chr_code==or_code) print_esc("or"); + else print_esc("else");@+break; + +@ When we skip conditional text, we keep track of the line number +where skipping began, for use in error messages. + +@<Glob...@>= +static int @!skip_line; /*skipping began here*/ + +@ Here is a procedure that ignores text until coming to an \.{\\or}, +\.{\\else}, or \.{\\fi} at level zero of $\.{\\if}\ldots\.{\\fi}$ +nesting. After it has acted, |cur_chr| will indicate the token that +was found, but |cur_tok| will not be set (because this makes the +procedure run faster). + +@p static void pass_text(void) +{@+ +int l; /*level of $\.{\\if}\ldots\.{\\fi}$ nesting*/ +small_number @!save_scanner_status; /*|scanner_status| upon entry*/ +save_scanner_status=scanner_status;scanner_status=skipping;l=0; +skip_line=line; +loop@+{@+get_next(); + if (cur_cmd==fi_or_else) + {@+if (l==0) goto done; + if (cur_chr==fi_code) decr(l); + } + else if (cur_cmd==if_test) incr(l); + } +done: scanner_status=save_scanner_status; +if (tracing_ifs > 0) show_cur_cmd_chr(); +} + +@ When we begin to process a new \.{\\if}, we set |if_limit=if_code|; then +if\/ \.{\\or} or \.{\\else} or \.{\\fi} occurs before the current \.{\\if} +condition has been evaluated, \.{\\relax} will be inserted. +For example, a sequence of commands like `\.{\\ifvoid1\\else...\\fi}' +would otherwise require something after the `\.1'. + +@<Push the condition stack@>= +{@+p=get_node(if_node_size);link(p)=cond_ptr;type(p)=if_limit; +subtype(p)=cur_if;if_line_field(p)=if_line; +cond_ptr=p;cur_if=cur_chr;if_limit=if_code;if_line=line; +} + +@ @<Pop the condition stack@>= +{@+if (if_stack[in_open]==cond_ptr) if_warning(); + /*conditionals possibly not properly nested with files*/ +p=cond_ptr;if_line=if_line_field(p); +cur_if=subtype(p);if_limit=type(p);cond_ptr=link(p); +free_node(p, if_node_size); +} + +@ Here's a procedure that changes the |if_limit| code corresponding to +a given value of |cond_ptr|. + +@p static void change_if_limit(small_number @!l, pointer @!p) +{@+ +pointer q; +if (p==cond_ptr) if_limit=l; /*that's the easy case*/ +else{@+q=cond_ptr; + loop@+{@+if (q==null) confusion("if"); +@:this can't happen if}{\quad if@> + if (link(q)==p) + {@+type(q)=l;return; + } + q=link(q); + } + } +} + +@ A condition is started when the |expand| procedure encounters +an |if_test| command; in that case |expand| reduces to |conditional|, +which is a recursive procedure. +@^recursion@> + +@p static void conditional(void) +{@+ +bool b; /*is the condition true?*/ +int @!r; /*relation to be evaluated*/ +int @!m, @!n; /*to be tested against the second operand*/ +pointer @!p, @!q; /*for traversing token lists in \.{\\ifx} tests*/ +small_number @!save_scanner_status; /*|scanner_status| upon entry*/ +pointer @!save_cond_ptr; /*|cond_ptr| corresponding to this conditional*/ +small_number @!this_if; /*type of this conditional*/ +bool @!is_unless; /*was this if preceded by `\.{\\unless}' ?*/ +if (tracing_ifs > 0) if (tracing_commands <= 1) show_cur_cmd_chr(); +@<Push the condition stack@>;@+save_cond_ptr=cond_ptr; +is_unless=(cur_chr >= unless_code);this_if=cur_chr%unless_code;@/ +@<Either process \.{\\ifcase} or set |b| to the value of a boolean condition@>; +if (is_unless) b=!b; +if (tracing_commands > 1) @<Display the value of |b|@>; +if (b) + {@+change_if_limit(else_code, save_cond_ptr); + return; /*wait for \.{\\else} or \.{\\fi}*/ + } +@<Skip to \.{\\else} or \.{\\fi}, then |goto common_ending|@>; +common_ending: if (cur_chr==fi_code) @<Pop the condition stack@>@; +else if_limit=fi_code; /*wait for \.{\\fi}*/ +} + +@ In a construction like `\.{\\if\\iftrue abc\\else d\\fi}', the first +\.{\\else} that we come to after learning that the \.{\\if} is false is +not the \.{\\else} we're looking for. Hence the following curious +logic is needed. + +@ @<Skip to \.{\\else} or \.{\\fi}...@>= +loop@+{@+pass_text(); + if (cond_ptr==save_cond_ptr) + {@+if (cur_chr!=or_code) goto common_ending; + print_err("Extra ");print_esc("or"); +@.Extra \\or@> + help1("I'm ignoring this; it doesn't match any \\if."); + error(); + } + else if (cur_chr==fi_code) @<Pop the condition stack@>; + } + +@ @<Either process \.{\\ifcase} or set |b|...@>= +switch (this_if) { +case if_char_code: case if_cat_code: @<Test if two characters match@>@;@+break; +case if_int_code: case if_dim_code: @<Test relation between integers or dimensions@>@;@+break; +case if_odd_code: @<Test if an integer is odd@>@;@+break; +case if_vmode_code: b=(abs(mode)==vmode);@+break; +case if_hmode_code: b=(abs(mode)==hmode);@+break; +case if_mmode_code: b=(abs(mode)==mmode);@+break; +case if_inner_code: b=(mode < 0);@+break; +case if_void_code: case if_hbox_code: case if_vbox_code: @<Test box register status@>@;@+break; +case ifx_code: @<Test if two tokens match@>@;@+break; +case if_eof_code: {@+scan_four_bit_int();b=(read_open[cur_val]==closed); + } @+break; +case if_true_code: b=true;@+break; +case if_false_code: b=false;@+break; +@/@<Cases for |conditional|@>@/ +case if_case_code: @<Select the appropriate case and |return| or |goto common_ending|@>; +} /*there are no other cases*/ + +@ @<Display the value of |b|@>= +{@+begin_diagnostic(); +if (b) print("{true}");@+else print("{false}"); +end_diagnostic(false); +} + +@ Here we use the fact that |'<'|, |'='|, and |'>'| are consecutive ASCII +codes. +@^ASCII code@> + +@<Test relation between integers or dimensions@>= +{@+if (this_if==if_int_code) scan_int();@+else scan_normal_dimen; +n=cur_val;@<Get the next non-blank non-call...@>; +if ((cur_tok >= other_token+'<')&&(cur_tok <= other_token+'>')) + r=cur_tok-other_token; +else{@+print_err("Missing = inserted for "); +@.Missing = inserted@> + print_cmd_chr(if_test, this_if); + help1("I was expecting to see `<', `=', or `>'. Didn't."); + back_error();r='='; + } +if (this_if==if_int_code) scan_int();@+else scan_normal_dimen; +switch (r) { +case '<': b=(n < cur_val);@+break; +case '=': b=(n==cur_val);@+break; +case '>': b=(n > cur_val); +} +} + +@ @<Test if an integer is odd@>= +{@+scan_int();b=odd(cur_val); +} + +@ @<Test box register status@>= +{@+scan_register_num();fetch_box(p); +if (this_if==if_void_code) b=(p==null); +else if (p==null) b=false; +else if (this_if==if_hbox_code) b=(type(p)==hlist_node); +else b=(type(p)==vlist_node); +} + +@ An active character will be treated as category 13 following +\.{\\if\\noexpand} or following \.{\\ifcat\\noexpand}. We use the fact that +active characters have the smallest tokens, among all control sequences. + +@d get_x_token_or_active_char @t@>@; + {@+get_x_token(); + if (cur_cmd==relax) if (cur_chr==no_expand_flag) + {@+cur_cmd=active_char; + cur_chr=cur_tok-cs_token_flag-active_base; + } + } + +@<Test if two characters match@>= +{@+get_x_token_or_active_char; +if ((cur_cmd > active_char)||(cur_chr > 255)) /*not a character*/ + {@+m=relax;n=256; + } +else{@+m=cur_cmd;n=cur_chr; + } +get_x_token_or_active_char; +if ((cur_cmd > active_char)||(cur_chr > 255)) + {@+cur_cmd=relax;cur_chr=256; + } +if (this_if==if_char_code) b=(n==cur_chr);@+else b=(m==cur_cmd); +} + +@ Note that `\.{\\ifx}' will declare two macros different if one is \\{long} +or \\{outer} and the other isn't, even though the texts of the macros are +the same. + +We need to reset |scanner_status|, since \.{\\outer} control sequences +are allowed, but we might be scanning a macro definition or preamble. + +@<Test if two tokens match@>= +{@+save_scanner_status=scanner_status;scanner_status=normal; +get_next();n=cur_cs;p=cur_cmd;q=cur_chr; +get_next();if (cur_cmd!=p) b=false; +else if (cur_cmd < call) b=(cur_chr==q); +else@<Test if two macro texts match@>; +scanner_status=save_scanner_status; +} + +@ Note also that `\.{\\ifx}' decides that macros \.{\\a} and \.{\\b} are +different in examples like this: +$$\vbox{\halign{\.{#}\hfil&\qquad\.{#}\hfil\cr + {}\\def\\a\{\\c\}& + {}\\def\\c\{\}\cr + {}\\def\\b\{\\d\}& + {}\\def\\d\{\}\cr}}$$ + +@<Test if two macro texts match@>= +{@+p=link(cur_chr);q=link(equiv(n)); /*omit reference counts*/ +if (p==q) b=true; +else{@+while ((p!=null)&&(q!=null)) + if (info(p)!=info(q)) p=null; + else{@+p=link(p);q=link(q); + } + b=((p==null)&&(q==null)); + } +} + +@ @<Select the appropriate case and |return| or |goto common_ending|@>= +{@+scan_int();n=cur_val; /*|n| is the number of cases to pass*/ +if (tracing_commands > 1) + {@+begin_diagnostic();print("{case ");print_int(n);print_char('}'); + end_diagnostic(false); + } +while (n!=0) + {@+pass_text(); + if (cond_ptr==save_cond_ptr) + if (cur_chr==or_code) decr(n); + else goto common_ending; + else if (cur_chr==fi_code) @<Pop the condition stack@>; + } +change_if_limit(or_code, save_cond_ptr); +return; /*wait for \.{\\or}, \.{\\else}, or \.{\\fi}*/ +} + +@ The processing of conditionals is complete except for the following +code, which is actually part of |expand|. It comes into play when +\.{\\or}, \.{\\else}, or \.{\\fi} is scanned. + +@<Terminate the current conditional and skip to \.{\\fi}@>= +{@+if (tracing_ifs > 0) if (tracing_commands <= 1) show_cur_cmd_chr(); +if (cur_chr > if_limit) + if (if_limit==if_code) insert_relax(); /*condition not yet evaluated*/ + else{@+print_err("Extra ");print_cmd_chr(fi_or_else, cur_chr); +@.Extra \\or@> +@.Extra \\else@> +@.Extra \\fi@> + help1("I'm ignoring this; it doesn't match any \\if."); + error(); + } +else{@+while (cur_chr!=fi_code) pass_text(); /*skip to \.{\\fi}*/ + @<Pop the condition stack@>; + } +} + +@* File names. +It's time now to fret about file names. Besides the fact that different +operating systems treat files in different ways, we must cope with the +fact that completely different naming conventions are used by different +groups of people. The following programs show what is required for one +particular operating system; similar routines for other systems are not +difficult to devise. +@^fingers@> +@^system dependencies@> + +\TeX\ assumes that a file name has three parts: the name proper; its +``extension''; and a ``file area'' where it is found in an external file +system. The extension of an input file or a write file is assumed to be +`\.{.tex}' unless otherwise specified; it is `\.{.log}' on the +transcript file that records each run of \TeX; it is `\.{.tfm}' on the font +metric files that describe characters in the fonts \TeX\ uses; it is +`\.{.dvi}' on the output files that specify typesetting information; and it +is `\.{.fmt}' on the format files written by \.{INITEX} to initialize \TeX. +The file area can be arbitrary on input files, but files are usually +output to the user's current area. If an input file cannot be +found on the specified area, \TeX\ will look for it on a special system +area; this special area is intended for commonly used input files like +\.{webmac.tex}. + +Simple uses of \TeX\ refer only to file names that have no explicit +extension or area. For example, a person usually says `\.{\\input} \.{paper}' +or `\.{\\font\\tenrm} \.= \.{helvetica}' instead of `\.{\\input} +\.{paper.new}' or `\.{\\font\\tenrm} \.= \.{<csd.knuth>test}'. Simple file +names are best, because they make the \TeX\ source files portable; +whenever a file name consists entirely of letters and digits, it should be +treated in the same way by all implementations of \TeX. However, users +need the ability to refer to other files in their environment, especially +when responding to error messages concerning unopenable files; therefore +we want to let them use the syntax that appears in their favorite +operating system. + +The following procedures don't allow spaces to be part of +file names; but some users seem to like names that are spaced-out. +System-dependent changes to allow such things should probably +be made with reluctance, and only when an entire file name that +includes spaces is ``quoted'' somehow. + +@ In order to isolate the system-dependent aspects of file names, the +@^system dependencies@> +system-independent parts of \TeX\ are expressed in terms +of three system-dependent +procedures called |begin_name|, |more_name|, and |end_name|. In +essence, if the user-specified characters of the file name are $c_1\ldots c_n$, +the system-independent driver program does the operations +$$|begin_name|;\,|more_name|(c_1);\,\ldots\,;\,|more_name|(c_n); +\,|end_name|.$$ +These three procedures communicate with each other via global variables. +Afterwards the file name will appear in the string pool as three strings +called |cur_name|\penalty10000\hskip-.05em, +|cur_area|, and |cur_ext|; the latter two are null (i.e., +|""|), unless they were explicitly specified by the user. + +Actually the situation is slightly more complicated, because \TeX\ needs +to know when the file name ends. The |more_name| routine is a function +(with side effects) that returns |true| on the calls |more_name|$(c_1)$, +\dots, |more_name|$(c_{n-1})$. The final call |more_name|$(c_n)$ +returns |false|; or, it returns |true| and the token following $c_n$ is +something like `\.{\\hbox}' (i.e., not a character). In other words, +|more_name| is supposed to return |true| unless it is sure that the +file name has been completely scanned; and |end_name| is supposed to be able +to finish the assembly of |cur_name|, |cur_area|, and |cur_ext| regardless of +whether $|more_name|(c_n)$ returned |true| or |false|. + +@<Glob...@>= +static str_number @!cur_name; /*name of file just scanned*/ +static char *@!cur_area; /*file area just scanned, or \.{""}*/ +static char *@!cur_ext; /*file extension just scanned, or \.{""}*/ + +@ The file names we shall deal with for illustrative purposes have the +following structure: If the name contains `\.>' or `\.:', the file area +consists of all characters up to and including the final such character; +otherwise the file area is null. If the remaining file name contains +`\..', the file extension consists of all such characters from the first +remaining `\..' to the end, otherwise the file extension is null. +@^system dependencies@> + +We can scan such file names easily by using two global variables that keep track +of the occurrences of area and extension delimiters: + +@<Glob...@>= +static pool_pointer @!area_delimiter; /*the most recent `\.>' or `\.:', if any*/ +static pool_pointer @!ext_delimiter; /*the relevant `\..', if any*/ +static int @!cur_file_name_length; + +@ Input files that can't be found in the user's area may appear in a standard +system area called |TEX_area|. Font metric files whose areas are not given +explicitly are assumed to appear in a standard system area called +|TEX_font_area|. These system area names will, of course, vary from place +to place. +@^system dependencies@> + +@d TEX_area "TeXinputs/" +@.TeXinputs@> +@d TEX_font_area "TeXfonts/" +@.TeXfonts@> + +@ Here now is the first of the system-dependent routines for file name scanning. +@^system dependencies@> + +The filename is scanned into |cur_file_name|; |cur_ext| and |cur_aire| +will point into this buffer. + +@d MAX_CUR_FILE_NAME 1024 + +@p static char cur_file_name[MAX_CUR_FILE_NAME+1]; +static void begin_name(void) +{@+area_delimiter=ext_delimiter=cur_file_name_length=0; +} + +@ And here's the second. The string pool might change as the file name is +being scanned, since a new \.{\\csname} might be entered; therefore we keep +|area_delimiter| and |ext_delimiter| relative to the beginning of the current +string, instead of assigning an absolute address like |pool_ptr| to them. +@^system dependencies@> + +@p static bool more_name(ASCII_code @!c) +{@+if (c==' ') return false; + if (cur_file_name_length>= MAX_CUR_FILE_NAME ) + { overflow("file name length", MAX_CUR_FILE_NAME); + return false; + } + else + { /*contribute |c| to the current string*/ + cur_file_name[cur_file_name_length]=c; + if (c=='/') + {@+area_delimiter=cur_file_name_length;ext_delimiter=0; + } + else if (c=='.') ext_delimiter=cur_file_name_length; + cur_file_name_length++; + return true; + } +} + +@ The third. +@^system dependencies@> + +@p static void end_name(void) +{@+int i=0; + if (str_ptr+1 > max_strings) + overflow("number of strings", max_strings-init_str_ptr); +@:TeX capacity exceeded number of strings}{\quad number of strings@> +cur_file_name[cur_file_name_length]=0; +if (area_delimiter==0) cur_area=cur_file_name+cur_file_name_length; +else @+cur_area=cur_file_name,i=area_delimiter+1; +if (ext_delimiter==0) ext_delimiter=cur_file_name_length; +cur_ext=cur_file_name+ext_delimiter; +for (;i<ext_delimiter;i++) append_char(cur_file_name[i]); +if (area_delimiter!=0) cur_file_name[area_delimiter+1]=0; +cur_name=make_string(); +} + +static void set_cur_area_ext(str_number a, str_number e) +{ int i; + if (length(a)+length(e)+2>=MAX_CUR_FILE_NAME) + { overflow("file name length", MAX_CUR_FILE_NAME); + return; + } + cur_file_name_length=0; + area_delimiter=0; + for(i=str_start[a]; i<str_start[a+1];i++) cur_file_name[cur_file_name_length++]=str_pool[i]; + cur_file_name[cur_file_name_length++]=0; + cur_area=cur_file_name; + cur_ext=cur_file_name+cur_file_name_length; + for(i=str_start[e]; i<str_start[e+1];i++) cur_file_name[cur_file_name_length++]=str_pool[i]; + cur_file_name[cur_file_name_length++]=0; +} + +@ Conversely, here is a routine that takes three strings and prints a file +name that might have produced them. (The routine is system dependent, because +some operating systems put the file area last instead of first.) +@^system dependencies@> + +@<Basic printing...@>= +static void print_file_name(int @!n, char *@!a, char *@!e) +{@+print(a);slow_print(n);print(e); +} + +static void printn_file_name(int @!n, int @!a, int @!e) +{@+slow_print(a);slow_print(n);slow_print(e); +} + +@ Another system-dependent routine is needed to convert three internal +\TeX\ strings +into the |name_of_file| value that is used to open files. The present code +allows both lowercase and uppercase letters in the file name. +@^system dependencies@> + +@d append_to_name(A) {@+c=A;incr(k); + if (k <= file_name_size) name_of_file[k]=xchr[c]; + } + +@p void pack_file_name(str_number @!n, char *@!a, char *@!e) +{@+int k; /*number of positions filled in |name_of_file|*/ +ASCII_code @!c; /*character being packed*/ +int @!j; /*index into |str_pool|*/ +k=0; +while(*a!=0) append_to_name(so(*a++)); +for (j=str_start[n]; j<=str_start[n+1]-1; j++) append_to_name(so(str_pool[j])); +while(*e!=0) append_to_name(so(*e++)); +if (k <= file_name_size) name_length=k;@+else name_length=file_name_size; +name_of_file[name_length+1]=0; +} + + +@ The global variable |TEX_format_default| is no longer needed +to supply the text for default system areas +and extensions related to format files. + +@ Consequently there is no initialization of |TEX_format_default| either. + +@ And there is no need to check the length of |TEX_format_default|. + +@ The |format_extension|, however, is needed later on +to create the format name from the job name. + +@d format_extension ".fmt" + +@ This part of the program +becomes active when a ``virgin'' \TeX\ is trying to get going, just after +the preliminary initialization, or when the user is substituting another +format file by typing `\.\&' after the initial `\.{**}' prompt. The buffer +contains the first line of input in |buffer[loc dotdot(last-1)]|, where +|loc < last| and |buffer[loc]!=' '|. + +k\TeX\ uses the {\tt kpathsearch} library to implement access to files. +To do so we declare |open_fmt_file| here and postpone the +actual implementation. + +@<Declare the function called |open_fmt_file|@>= +static bool open_fmt_file(void); + +@ Operating systems often make it possible to determine the exact name (and +possible version number) of a file that has been opened. The following routine, +which simply makes a \TeX\ string from the value of |name_of_file|, should +ideally be changed to deduce the full name of file~|f|, which is the file +most recently opened, if it is possible to do this in a \PASCAL\ program. +@^system dependencies@> + +This routine might be called after string memory has overflowed, hence +we dare not use `|str_room|'. + +@p static str_number make_name_string(void) +{@+int k; /*index into |name_of_file|*/ +if ((pool_ptr+name_length > pool_size)||(str_ptr==max_strings)|| + (cur_length > 0)) + return'?'; +else{@+for (k=1; k<=name_length; k++) append_char(xord[name_of_file[k]]); + return make_string(); + } +} +static str_number a_make_name_string(alpha_file *f) +{@+return make_name_string(); +} +static str_number b_make_name_string(byte_file *f) +{@+return make_name_string(); +} +#ifdef @!INIT +static str_number w_make_name_string(word_file *f) +{@+return make_name_string(); +} +#endif + +@ Now let's consider the ``driver'' +routines by which \TeX\ deals with file names +in a system-independent manner. First comes a procedure that looks for a +file name in the input by calling |get_x_token| for the information. + +@p static void scan_file_name(void) +{@+ +name_in_progress=true;begin_name(); +@<Get the next non-blank non-call...@>; +loop@+{@+if ((cur_cmd > other_char)||(cur_chr > 255)) /*not a character*/ + {@+back_input();goto done; + } + if (!more_name(cur_chr)) goto done; + get_x_token(); + } +done: end_name();name_in_progress=false; +} + +@ The global variable |name_in_progress| is used to prevent recursive +use of |scan_file_name|, since the |begin_name| and other procedures +communicate via global variables. Recursion would arise only by +devious tricks like `\.{\\input\\input f}'; such attempts at sabotage +must be thwarted. Furthermore, |name_in_progress| prevents \.{\\input} +@^recursion@> +from being initiated when a font size specification is being scanned. + +Another global variable, |job_name|, contains the file name that was first +\.{\\input} by the user. This name is extended by `\.{.log}' and `\.{.dvi}' +and `\.{.fmt}' in the names of \TeX's output files. + +@<Glob...@>= +static bool @!name_in_progress; /*is a file name being scanned?*/ +str_number @!job_name; /*principal file name*/ +static bool @!log_opened; /*has the transcript file been opened?*/ + +@ Initially |job_name==0|; it becomes nonzero as soon as the true name is known. +We have |job_name==0| if and only if the `\.{log}' file has not been opened, +except of course for a short time just after |job_name| has become nonzero. + +@<Initialize the output...@>= +job_name=0;name_in_progress=false;log_opened=false; + +@ Here is a routine that manufactures the output file names, assuming that +|job_name!=0|. It ignores and changes the current settings of |cur_area| +and |cur_ext|. + +@d pack_cur_name pack_file_name(cur_name, cur_area, cur_ext) + +@p void pack_job_name(char *@!s) /*|s==".log"|, |".dvi"|, or + |format_extension|*/ +{@+cur_area="";cur_ext=s; +cur_name=job_name;pack_cur_name; +} + +@ If some trouble arises when \TeX\ tries to open a file, the following +routine calls upon the user to supply another file name. Parameter~|s| +is used in the error message to identify the type of file; parameter~|e| +is the default extension if none is given. Upon exit from the routine, +variables |cur_name|, |cur_area|, |cur_ext|, and |name_of_file| are +ready for another attempt at file opening. + +@p void prompt_file_name(char *@!s, char *@!e) +{@+ +int k; /*index into |buffer|*/ +if (interaction==scroll_mode) wake_up_terminal; +if (strcmp(s,"input file name")==0) print_err("I can't find file `"); +@.I can't find file x@> +else print_err("I can't write on file `"); +@.I can't write on file x@> +print_file_name(cur_name, cur_area, cur_ext);print("'."); +if (strcmp(e,".tex")==0) show_context(); +print_nl("Please type another ");print(s); +@.Please type...@> +if (interaction < scroll_mode) + fatal_error("*** (job aborted, file error in nonstop mode)"); +@.job aborted, file error...@> +clear_terminal;prompt_input(": ");@<Scan file name in the buffer@>; +if (cur_ext[0]==0) cur_ext=e; +pack_cur_name; +} + +@ @<Scan file name in the buffer@>= +{@+begin_name();k=first; +while ((buffer[k]==' ')&&(k < last)) incr(k); +loop@+{@+if (k==last) goto done; + if (!more_name(buffer[k])) goto done; + incr(k); + } +done: end_name(); +} + +@ Here's an example of how these conventions are used. Whenever it is time to +ship out a box of stuff, we shall use the macro |ensure_dvi_open|. + +@d ensure_dvi_open if (output_file_name==0) + {@+if (job_name==0) open_log_file(); + pack_job_name(".dvi"); + while (!b_open_out(&dvi_file)) + prompt_file_name("file name for output",".dvi"); + output_file_name=b_make_name_string(&dvi_file); + } + +@<Glob...@>= +static byte_file @!dvi_file; /*the device-independent output goes here*/ +static str_number @!output_file_name; /*full name of the output file*/ +static str_number @!log_name; /*full name of the log file*/ + +@ @<Initialize the output...@>=output_file_name=0; + +@ The |open_log_file| routine is used to open the transcript file and to help +it catch up to what has previously been printed on the terminal. + +@p void open_log_file(void) +{@+int old_setting; /*previous |selector| setting*/ +int @!k; /*index into |months| and |buffer|*/ +int @!l; /*end of first input line*/ +char @!months[]=" JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC"; /*abbreviations of month names*/ +old_setting=selector; +if (job_name==0) job_name=s_no(c_job_name?c_job_name:"texput"); /* k\TeX\ */ +@.texput@> +pack_job_name(".log"); +while (!a_open_out(&log_file)) @<Try to get a different log file name@>; +log_name=a_make_name_string(&log_file); +selector=log_only;log_opened=true; +@<Print the banner line, including the date and time@>; +input_stack[input_ptr]=cur_input; /*make sure bottom level is in memory*/ +print_nl("**"); +@.**@> +l=input_stack[0].limit_field; /*last position of first line*/ +if (buffer[l]==end_line_char) decr(l); +for (k=1; k<=l; k++) printn(buffer[k]); +print_ln(); /*now the transcript file contains the first line of input*/ +selector=old_setting+2; /*|log_only| or |term_and_log|*/ +} + +@ Sometimes |open_log_file| is called at awkward moments when \TeX\ is +unable to print error messages or even to |show_context|. +The |prompt_file_name| routine can result in a |fatal_error|, but the |error| +routine will not be invoked because |log_opened| will be false. + +The normal idea of |batch_mode| is that nothing at all should be written +on the terminal. However, in the unusual case that +no log file could be opened, we make an exception and allow +an explanatory message to be seen. + +Incidentally, the program always refers to the log file as a `\.{transcript +file}', because some systems cannot use the extension `\.{.log}' for +this file. + +@<Try to get a different log file name@>= +{@+selector=term_only; +prompt_file_name("transcript file name",".log"); +} + +@ @<Print the banner...@>= +{@+wlog("%s",banner); +slow_print(format_ident);print(" "); +print_int(day);print_char(' '); +for (k=3*month-2; k<=3*month; k++) wlog("%c",months[k]); +print_char(' ');print_int(year);print_char(' '); +print_two(time/60);print_char(':');print_two(time%60); +if (eTeX_ex) + {@+;wlog_cr;wlog("entering extended mode"); + } +} + +@ Let's turn now to the procedure that is used to initiate file reading +when an `\.{\\input}' command is being processed. + +@p static void start_input(void) /*\TeX\ will \.{\\input} something*/ +{@+ +scan_file_name(); /*set |cur_name| to desired file name*/ +if (cur_ext[0]==0) cur_ext=".tex"; +pack_cur_name; +loop@+{@+begin_file_reading(); /*set up |cur_file| and new level of input*/ + if (a_open_in(&cur_file)) goto done; + end_file_reading(); /*remove the level that didn't work*/ + prompt_file_name("input file name",".tex"); + } +done: name=a_make_name_string(&cur_file);@/ +source_filename_stack[in_open]=name; /* k\TeX\ */ +if (job_name==0) + {@+if (c_job_name==NULL) job_name=cur_name; + else job_name=s_no(c_job_name); open_log_file(); /* k\TeX\ */ + } /*|open_log_file| doesn't |show_context|, so |limit| + and |loc| needn't be set to meaningful values yet*/ +if (term_offset+length(name) > max_print_line-2) print_ln(); +else if ((term_offset > 0)||(file_offset > 0)) print_char(' '); +print_char('(');incr(open_parens);slow_print(name);update_terminal; +state=new_line; +if (name==str_ptr-1) /*we can conserve string pool space now*/ + {@+flush_string;name=cur_name; + } +@<Read the first line of the new file@>; +} + +@ Here we have to remember to tell the |input_ln| routine not to +start with a |get|. If the file is empty, it is considered to +contain a single blank line. +@^system dependencies@> +@^empty line at end of file@> + +@<Read the first line...@>= +{@+line=1; +if (input_ln(&cur_file, false)) do_nothing; +firm_up_the_line(); +if (end_line_char_inactive) decr(limit); +else buffer[limit]=end_line_char; +first=limit+1;loc=start; +} + +@* Font metric data. +\TeX\ gets its knowledge about fonts from font metric files, also called +\.{TFM} files; the `\.T' in `\.{TFM}' stands for \TeX, +but other programs know about them too. +@:TFM files}{\.{TFM} files@> +@^font metric files@> + +The information in a \.{TFM} file appears in a sequence of 8-bit bytes. +Since the number of bytes is always a multiple of 4, we could +also regard the file as a sequence of 32-bit words, but \TeX\ uses the +byte interpretation. The format of \.{TFM} files was designed by +Lyle Ramshaw in 1980. The intent is to convey a lot of different kinds +@^Ramshaw, Lyle Harold@> +of information in a compact but useful form. + +@<Glob...@>= +static byte_file @!tfm_file; + +@ The first 24 bytes (6 words) of a \.{TFM} file contain twelve 16-bit +integers that give the lengths of the various subsequent portions +of the file. These twelve integers are, in order: +$$\vbox{\halign{\hfil#&$\null=\null$#\hfil\cr +|lf|&length of the entire file, in words;\cr +|lh|&length of the header data, in words;\cr +|bc|&smallest character code in the font;\cr +|ec|&largest character code in the font;\cr +|nw|&number of words in the width table;\cr +|nh|&number of words in the height table;\cr +|nd|&number of words in the depth table;\cr +|ni|&number of words in the italic correction table;\cr +|nl|&number of words in the lig/kern table;\cr +|nk|&number of words in the kern table;\cr +|ne|&number of words in the extensible character table;\cr +|np|&number of font parameter words.\cr}}$$ +They are all nonnegative and less than $2^{15}$. We must have |bc-1 <= ec <= 255|, +and +$$\hbox{|lf==6+lh+(ec-bc+1)+nw+nh+nd+ni+nl+nk+ne+np|.}$$ +Note that a font may contain as many as 256 characters (if |bc==0| and |ec==255|), +and as few as 0 characters (if |bc==ec+1|). + +Incidentally, when two or more 8-bit bytes are combined to form an integer of +16 or more bits, the most significant bytes appear first in the file. +This is called BigEndian order. +@!@^BigEndian order@> + +@ The rest of the \.{TFM} file may be regarded as a sequence of ten data +arrays having the informal specification +$$\def\arr$[#1]#2${\&{array} $[#1]$ \&{of} #2} +\def\PB#1{\arr#1} +\vbox{\halign{\hfil\\{#}&$\,:\,$#\hfil\cr +header&|[0 dotdot lh-1]@t\\{stuff}@>|\cr +char\_info&|[bc dotdot ec]char_info_word|\cr +width&|[0 dotdot nw-1]fix_word|\cr +height&|[0 dotdot nh-1]fix_word|\cr +depth&|[0 dotdot nd-1]fix_word|\cr +italic&|[0 dotdot ni-1]fix_word|\cr +lig\_kern&|[0 dotdot nl-1]lig_kern_command|\cr +kern&|[0 dotdot nk-1]fix_word|\cr +exten&|[0 dotdot ne-1]extensible_recipe|\cr +param&|[1 dotdot np]fix_word|\cr}}$$ +The most important data type used here is a |@!fix_word|, which is +a 32-bit representation of a binary fraction. A |fix_word| is a signed +quantity, with the two's complement of the entire word used to represent +negation. Of the 32 bits in a |fix_word|, exactly 12 are to the left of the +binary point; thus, the largest |fix_word| value is $2048-2^{-20}$, and +the smallest is $-2048$. We will see below, however, that all but two of +the |fix_word| values must lie between $-16$ and $+16$. + +@ The first data array is a block of header information, which contains +general facts about the font. The header must contain at least two words, +|header[0]| and |header[1]|, whose meaning is explained below. +Additional header information of use to other software routines might +also be included, but \TeX82 does not need to know about such details. +For example, 16 more words of header information are in use at the Xerox +Palo Alto Research Center; the first ten specify the character coding +scheme used (e.g., `\.{XEROX text}' or `\.{TeX math symbols}'), the next five +give the font identifier (e.g., `\.{HELVETICA}' or `\.{CMSY}'), and the +last gives the ``face byte.'' The program that converts \.{DVI} files +to Xerox printing format gets this information by looking at the \.{TFM} +file, which it needs to read anyway because of other information that +is not explicitly repeated in \.{DVI}~format. + +\yskip\hang|header[0]| is a 32-bit check sum that \TeX\ will copy into +the \.{DVI} output file. Later on when the \.{DVI} file is printed, +possibly on another computer, the actual font that gets used is supposed +to have a check sum that agrees with the one in the \.{TFM} file used by +\TeX. In this way, users will be warned about potential incompatibilities. +(However, if the check sum is zero in either the font file or the \.{TFM} +file, no check is made.) The actual relation between this check sum and +the rest of the \.{TFM} file is not important; the check sum is simply an +identification number with the property that incompatible fonts almost +always have distinct check sums. +@^check sum@> + +\yskip\hang|header[1]| is a |fix_word| containing the design size of +the font, in units of \TeX\ points. This number must be at least 1.0; it is +fairly arbitrary, but usually the design size is 10.0 for a ``10 point'' +font, i.e., a font that was designed to look best at a 10-point size, +whatever that really means. When a \TeX\ user asks for a font +`\.{at} $\delta$ \.{pt}', the effect is to override the design size +and replace it by $\delta$, and to multiply the $x$ and~$y$ coordinates +of the points in the font image by a factor of $\delta$ divided by the +design size. {\sl All other dimensions in the\/ \.{TFM} file are +|fix_word|\kern-1pt\ numbers in design-size units}, with the exception of +|param[1]| (which denotes the slant ratio). Thus, for example, the value +of |param[6]|, which defines the \.{em} unit, is often the |fix_word| value +$2^{20}=1.0$, since many fonts have a design size equal to one em. +The other dimensions must be less than 16 design-size units in absolute +value; thus, |header[1]| and |param[1]| are the only |fix_word| +entries in the whole \.{TFM} file whose first byte might be something +besides 0 or 255. + +@ Next comes the |char_info| array, which contains one |@!char_info_word| +per character. Each word in this part of the file contains six fields +packed into four bytes as follows. + +\yskip\hang first byte: |@!width_index| (8 bits)\par +\hang second byte: |@!height_index| (4 bits) times 16, plus |@!depth_index| + (4~bits)\par +\hang third byte: |@!italic_index| (6 bits) times 4, plus |@!tag| + (2~bits)\par +\hang fourth byte: |@!rem| (8 bits)\par +\yskip\noindent +The actual width of a character is \\{width}|[width_index]|, in design-size +units; this is a device for compressing information, since many characters +have the same width. Since it is quite common for many characters +to have the same height, depth, or italic correction, the \.{TFM} format +imposes a limit of 16 different heights, 16 different depths, and +64 different italic corrections. + +@!@^italic correction@> +The italic correction of a character has two different uses. +(a)~In ordinary text, the italic correction is added to the width only if +the \TeX\ user specifies `\.{\\/}' after the character. +(b)~In math formulas, the italic correction is always added to the width, +except with respect to the positioning of subscripts. + +Incidentally, the relation $\\{width}[0]=\\{height}[0]=\\{depth}[0]= +\\{italic}[0]=0$ should always hold, so that an index of zero implies a +value of zero. The |width_index| should never be zero unless the +character does not exist in the font, since a character is valid if and +only if it lies between |bc| and |ec| and has a nonzero |width_index|. + +@ The |tag| field in a |char_info_word| has four values that explain how to +interpret the |rem| field. + +\yskip\hangg|tag==0| (|no_tag|) means that |rem| is unused.\par +\hangg|tag==1| (|lig_tag|) means that this character has a ligature/kerning +program starting at position |rem| in the |lig_kern| array.\par +\hangg|tag==2| (|list_tag|) means that this character is part of a chain of +characters of ascending sizes, and not the largest in the chain. The +|rem| field gives the character code of the next larger character.\par +\hangg|tag==3| (|ext_tag|) means that this character code represents an +extensible character, i.e., a character that is built up of smaller pieces +so that it can be made arbitrarily large. The pieces are specified in +|@!exten[rem]|.\par +\yskip\noindent +Characters with |tag==2| and |tag==3| are treated as characters with |tag==0| +unless they are used in special circumstances in math formulas. For example, +the \.{\\sum} operation looks for a |list_tag|, and the \.{\\left} +operation looks for both |list_tag| and |ext_tag|. + +@d no_tag 0 /*vanilla character*/ +@d lig_tag 1 /*character has a ligature/kerning program*/ +@d list_tag 2 /*character has a successor in a charlist*/ +@d ext_tag 3 /*character is extensible*/ + +@ The |lig_kern| array contains instructions in a simple programming language +that explains what to do for special letter pairs. Each word in this array is a +|@!lig_kern_command| of four bytes. + +\yskip\hang first byte: |skip_byte|, indicates that this is the final program + step if the byte is 128 or more, otherwise the next step is obtained by + skipping this number of intervening steps.\par +\hang second byte: |next_char|, ``if |next_char| follows the current character, + then perform the operation and stop, otherwise continue.''\par +\hang third byte: |op_byte|, indicates a ligature step if less than~128, + a kern step otherwise.\par +\hang fourth byte: |rem|.\par +\yskip\noindent +In a kern step, an +additional space equal to |kern[256*(op_byte-128)+rem]| is inserted +between the current character and |next_char|. This amount is +often negative, so that the characters are brought closer together +by kerning; but it might be positive. + +There are eight kinds of ligature steps, having |op_byte| codes $4a+2b+c$ where +$0\le a\le b+c$ and $0\le b,c\le1$. The character whose code is +|rem| is inserted between the current character and |next_char|; +then the current character is deleted if $b=0$, and |next_char| is +deleted if $c=0$; then we pass over $a$~characters to reach the next +current character (which may have a ligature/kerning program of its own). + +If the very first instruction of the |lig_kern| array has |skip_byte==255|, +the |next_char| byte is the so-called right boundary character of this font; +the value of |next_char| need not lie between |bc| and~|ec|. +If the very last instruction of the |lig_kern| array has |skip_byte==255|, +there is a special ligature/kerning program for a left boundary character, +beginning at location |256*op_byte+rem|. +The interpretation is that \TeX\ puts implicit boundary characters +before and after each consecutive string of characters from the same font. +These implicit characters do not appear in the output, but they can affect +ligatures and kerning. + +If the very first instruction of a character's |lig_kern| program has +|skip_byte > 128|, the program actually begins in location +|256*op_byte+rem|. This feature allows access to large |lig_kern| +arrays, because the first instruction must otherwise +appear in a location | <= 255|. + +Any instruction with |skip_byte > 128| in the |lig_kern| array must satisfy +the condition +$$\hbox{|256*op_byte+rem < nl|.}$$ +If such an instruction is encountered during +normal program execution, it denotes an unconditional halt; no ligature +or kerning command is performed. + +@d stop_flag qi(128) /*value indicating `\.{STOP}' in a lig/kern program*/ +@d kern_flag qi(128) /*op code for a kern step*/ +@d skip_byte(A) A.b0 +@d next_char(A) A.b1 +@d op_byte(A) A.b2 +@d rem_byte(A) A.b3 + +@ Extensible characters are specified by an |@!extensible_recipe|, which +consists of four bytes called |@!top|, |@!mid|, |@!bot|, and |@!rep| (in this +order). These bytes are the character codes of individual pieces used to +build up a large symbol. If |top|, |mid|, or |bot| are zero, they are not +present in the built-up result. For example, an extensible vertical line is +like an extensible bracket, except that the top and bottom pieces are missing. + +Let $T$, $M$, $B$, and $R$ denote the respective pieces, or an empty box +if the piece isn't present. Then the extensible characters have the form +$TR^kMR^kB$ from top to bottom, for some |k >= 0|, unless $M$ is absent; +in the latter case we can have $TR^kB$ for both even and odd values of~|k|. +The width of the extensible character is the width of $R$; and the +height-plus-depth is the sum of the individual height-plus-depths of the +components used, since the pieces are butted together in a vertical list. + +@d ext_top(A) A.b0 /*|top| piece in a recipe*/ +@d ext_mid(A) A.b1 /*|mid| piece in a recipe*/ +@d ext_bot(A) A.b2 /*|bot| piece in a recipe*/ +@d ext_rep(A) A.b3 /*|rep| piece in a recipe*/ + +@ The final portion of a \.{TFM} file is the |param| array, which is another +sequence of |fix_word| values. + +\yskip\hang|param[1]==slant| is the amount of italic slant, which is used +to help position accents. For example, |slant==.25| means that when you go +up one unit, you also go .25 units to the right. The |slant| is a pure +number; it's the only |fix_word| other than the design size itself that is +not scaled by the design size. + +\hang|param[2]==space| is the normal spacing between words in text. +Note that character |' '| in the font need not have anything to do with +blank spaces. + +\hang|param[3]==space_stretch| is the amount of glue stretching between words. + +\hang|param[4]==space_shrink| is the amount of glue shrinking between words. + +\hang|param[5]==x_height| is the size of one ex in the font; it is also +the height of letters for which accents don't have to be raised or lowered. + +\hang|param[6]==quad| is the size of one em in the font. + +\hang|param[7]==extra_space| is the amount added to |param[2]| at the +ends of sentences. + +\yskip\noindent +If fewer than seven parameters are present, \TeX\ sets the missing parameters +to zero. Fonts used for math symbols are required to have +additional parameter information, which is explained later. + +@d slant_code 1 +@d space_code 2 +@d space_stretch_code 3 +@d space_shrink_code 4 +@d x_height_code 5 +@d quad_code 6 +@d extra_space_code 7 + +@ So that is what \.{TFM} files hold. Since \TeX\ has to absorb such information +about lots of fonts, it stores most of the data in a large array called +|font_info|. Each item of |font_info| is a |memory_word|; the |fix_word| +data gets converted into |scaled| entries, while everything else goes into +words of type |four_quarters|. + +When the user defines \.{\\font\\f}, say, \TeX\ assigns an internal number +to the user's font~\.{\\f}. Adding this number to |font_id_base| gives the +|eqtb| location of a ``frozen'' control sequence that will always select +the font. + +@<Types...@>= +typedef uint8_t internal_font_number; /*|font| in a |char_node|*/ +typedef int32_t font_index; /*index into |font_info|*/ + +@ Here now is the (rather formidable) array of font arrays. + +@d non_char qi(256) /*a |halfword| code that can't match a real character*/ +@d non_address 0 /*a spurious |bchar_label|*/ + +@<Glob...@>= +memory_word @!font_info[font_mem_size+1]; + /*the big collection of font data*/ +static font_index @!fmem_ptr; /*first unused word of |font_info|*/ +static internal_font_number @!font_ptr; /*largest internal font number in use*/ +static four_quarters @!font_check0[font_max-font_base+1], *const @!font_check = @!font_check0-font_base; /*check sum*/ +scaled @!font_size0[font_max-font_base+1], *const @!font_size = @!font_size0-font_base; /*``at'' size*/ +scaled @!font_dsize0[font_max-font_base+1], *const @!font_dsize = @!font_dsize0-font_base; /*``design'' size*/ +static font_index @!font_params0[font_max-font_base+1], *const @!font_params = @!font_params0-font_base; /*how many font + parameters are present*/ +str_number @!font_name0[font_max-font_base+1], *const @!font_name = @!font_name0-font_base; /*name of the font*/ +static str_number @!font_area0[font_max-font_base+1], *const @!font_area = @!font_area0-font_base; /*area of the font*/ +static eight_bits @!font_bc0[font_max-font_base+1], *const @!font_bc = @!font_bc0-font_base; + /*beginning (smallest) character code*/ +static eight_bits @!font_ec0[font_max-font_base+1], *const @!font_ec = @!font_ec0-font_base; + /*ending (largest) character code*/ +pointer @!font_glue0[font_max-font_base+1], *const @!font_glue = @!font_glue0-font_base; + /*glue specification for interword space, |null| if not allocated*/ +static bool @!font_used0[font_max-font_base+1], *const @!font_used = @!font_used0-font_base; + /*has a character from this font actually appeared in the output?*/ +int @!hyphen_char0[font_max-font_base+1], *const @!hyphen_char = @!hyphen_char0-font_base; + /*current \.{\\hyphenchar} values*/ +static int @!skew_char0[font_max-font_base+1], *const @!skew_char = @!skew_char0-font_base; + /*current \.{\\skewchar} values*/ +static font_index @!bchar_label0[font_max-font_base+1], *const @!bchar_label = @!bchar_label0-font_base; + /*start of |lig_kern| program for left boundary character, + |non_address| if there is none*/ +static int16_t @!font_bchar0[font_max-font_base+1], *const @!font_bchar = @!font_bchar0-font_base; + /*right boundary character, |non_char| if there is none*/ +static int16_t @!font_false_bchar0[font_max-font_base+1], *const @!font_false_bchar = @!font_false_bchar0-font_base; + /*|font_bchar| if it doesn't exist in the font, otherwise |non_char|*/ + +@ Besides the arrays just enumerated, we have directory arrays that make it +easy to get at the individual entries in |font_info|. For example, the +|char_info| data for character |c| in font |f| will be in +|font_info[char_base[f]+c].qqqq|; and if |w| is the |width_index| +part of this word (the |b0| field), the width of the character is +|font_info[width_base[f]+w].sc|. (These formulas assume that +|min_quarterword| has already been added to |c| and to |w|, since \TeX\ +stores its quarterwords that way.) + +@<Glob...@>= +int @!char_base0[font_max-font_base+1], *const @!char_base = @!char_base0-font_base; + /*base addresses for |char_info|*/ +int @!width_base0[font_max-font_base+1], *const @!width_base = @!width_base0-font_base; + /*base addresses for widths*/ +int @!height_base0[font_max-font_base+1], *const @!height_base = @!height_base0-font_base; + /*base addresses for heights*/ +int @!depth_base0[font_max-font_base+1], *const @!depth_base = @!depth_base0-font_base; + /*base addresses for depths*/ +static int @!italic_base0[font_max-font_base+1], *const @!italic_base = @!italic_base0-font_base; + /*base addresses for italic corrections*/ +static int @!lig_kern_base0[font_max-font_base+1], *const @!lig_kern_base = @!lig_kern_base0-font_base; + /*base addresses for ligature/kerning programs*/ +static int @!kern_base0[font_max-font_base+1], *const @!kern_base = @!kern_base0-font_base; + /*base addresses for kerns*/ +static int @!exten_base0[font_max-font_base+1], *const @!exten_base = @!exten_base0-font_base; + /*base addresses for extensible recipes*/ +int @!param_base0[font_max-font_base+1], *const @!param_base = @!param_base0-font_base; + /*base addresses for font parameters*/ + +@ @<Set init...@>= +for (k=font_base; k<=font_max; k++) font_used[k]=false; + +@ \TeX\ always knows at least one font, namely the null font. It has no +characters, and its seven parameters are all equal to zero. + +@<Initialize table...@>= +font_ptr=null_font;fmem_ptr=7; +font_name[null_font]=s_no("nullfont");font_area[null_font]=empty_string; +hyphen_char[null_font]='-';skew_char[null_font]=-1; +bchar_label[null_font]=non_address; +font_bchar[null_font]=non_char;font_false_bchar[null_font]=non_char; +font_bc[null_font]=1;font_ec[null_font]=0; +font_size[null_font]=0;font_dsize[null_font]=0; +char_base[null_font]=0;width_base[null_font]=0; +height_base[null_font]=0;depth_base[null_font]=0; +italic_base[null_font]=0;lig_kern_base[null_font]=0; +kern_base[null_font]=0;exten_base[null_font]=0; +font_glue[null_font]=null;font_params[null_font]=7; +param_base[null_font]=-1; +for (k=0; k<=6; k++) font_info[k].sc=0; + +@ @<Put each...@>= +primitive("nullfont", set_font, null_font); +@!@:null\_font\_}{\.{\\nullfont} primitive@> +text(frozen_null_font)=text(cur_val);eqtb[frozen_null_font]=eqtb[cur_val]; + +@ Of course we want to define macros that suppress the detail of how font +information is actually packed, so that we don't have to write things like +$$\hbox{|font_info[width_base[f]+font_info[char_base[f]+c].qqqq.b0].sc|}$$ +too often. The \.{WEB} definitions here make |char_info(f)(c)| the +|four_quarters| word of font information corresponding to character +|c| of font |f|. If |q| is such a word, |char_width(f)(q)| will be +the character's width; hence the long formula above is at least +abbreviated to +$$\hbox{|char_width(f)(char_info(f)(c))|.}$$ +Usually, of course, we will fetch |q| first and look at several of its +fields at the same time. + +The italic correction of a character will be denoted by +|char_italic(f)(q)|, so it is analogous to |char_width|. But we will get +at the height and depth in a slightly different way, since we usually want +to compute both height and depth if we want either one. The value of +|height_depth(q)| will be the 8-bit quantity +$$b=|height_index|\times16+|depth_index|,$$ and if |b| is such a byte we +will write |char_height(f)(b)| and |char_depth(f)(b)| for the height and +depth of the character |c| for which |q==char_info(f)(c)|. Got that? + +The tag field will be called |char_tag(q)|; the remainder byte will be +called |rem_byte(q)|, using a macro that we have already defined above. + +Access to a character's |width|, |height|, |depth|, and |tag| fields is +part of \TeX's inner loop, so we want these macros to produce code that is +as fast as possible under the circumstances. +@^inner loop@> + +@d char_info(A, B) font_info[char_base[A]+B].qqqq +@d char_width(A, B) font_info[width_base[A]+B.b0].sc +@d char_exists(A) (A.b0 > min_quarterword) +@d char_italic(A, B) font_info[italic_base[A]+(qo(B.b2))/4].sc +@d height_depth(A) qo(A.b1) +@d char_height(A, B) font_info[height_base[A]+(B)/16].sc +@d char_depth(A, B) font_info[depth_base[A]+(B)%16].sc +@d char_tag(A) ((qo(A.b2))%4) + +@ The global variable |null_character| is set up to be a word of +|char_info| for a character that doesn't exist. Such a word provides a +convenient way to deal with erroneous situations. + +@<Glob...@>= +static four_quarters @!null_character; /*nonexistent character information*/ + +@ @<Set init...@>= +null_character.b0=min_quarterword;null_character.b1=min_quarterword; +null_character.b2=min_quarterword;null_character.b3=min_quarterword; + +@ Here are some macros that help process ligatures and kerns. +We write |char_kern(f)(j)| to find the amount of kerning specified by +kerning command~|j| in font~|f|. If |j| is the |char_info| for a character +with a ligature/kern program, the first instruction of that program is either +|i==font_info[lig_kern_start(f)(j)]| or |font_info[lig_kern_restart(f)(i)]|, +depending on whether or not |skip_byte(i) <= stop_flag|. + +The constant |kern_base_offset| should be simplified, for \PASCAL\ compilers +that do not do local optimization. +@^system dependencies@> + +@d char_kern(A, B) font_info[kern_base[A]+256*op_byte(B)+rem_byte(B)].sc +@d kern_base_offset 256*(128+min_quarterword) +@d lig_kern_start(A, B) lig_kern_base[A]+B.b3 /*beginning of lig/kern program*/ +@d lig_kern_restart(A, B) lig_kern_base[A]+256*op_byte(B)+rem_byte(B)+32768-kern_base_offset + +@ Font parameters are referred to as |slant(f)|, |space(f)|, etc. + +@d param_end(A) param_base[A]].sc +@d param(A) font_info[A+param_end +@d slant param(slant_code) /*slant to the right, per unit distance upward*/ +@d space param(space_code) /*normal space between words*/ +@d space_stretch param(space_stretch_code) /*stretch between words*/ +@d space_shrink param(space_shrink_code) /*shrink between words*/ +@d x_height param(x_height_code) /*one ex*/ +@d quad param(quad_code) /*one em*/ +@d extra_space param(extra_space_code) /*additional space at end of sentence*/ + +@<The em width for |cur_font|@>=quad(cur_font) + +@ @<The x-height for |cur_font|@>=x_height(cur_font) + +@ \TeX\ checks the information of a \.{TFM} file for validity as the +file is being read in, so that no further checks will be needed when +typesetting is going on. The somewhat tedious subroutine that does this +is called |read_font_info|. It has four parameters: the user font +identifier~|u|, the file name and area strings |nom| and |aire|, and the +``at'' size~|s|. If |s|~is negative, it's the negative of a scale factor +to be applied to the design size; |s==-1000| is the normal case. +Otherwise |s| will be substituted for the design size; in this +case, |s| must be positive and less than $2048\rm\,pt$ +(i.e., it must be less than $2^{27}$ when considered as an integer). + +The subroutine opens and closes a global file variable called |tfm_file|. +It returns the value of the internal font number that was just loaded. +If an error is detected, an error message is issued and no font +information is stored; |null_font| is returned in this case. + +@d abort goto bad_tfm /*do this when the \.{TFM} data is wrong*/ + +@p static internal_font_number read_font_info(pointer @!u, str_number @!nom, char *@!aire, + scaled @!s) /*input a \.{TFM} file*/ +{@+ +int k; /*index into |font_info|*/ +bool @!file_opened; /*was |tfm_file| successfully opened?*/ +halfword @!lf, @!lh, @!bc, @!ec, @!nw, @!nh, @!nd, @!ni, @!nl, @!nk, @!ne, @!np; + /*sizes of subfiles*/ +internal_font_number @!f; /*the new font's number*/ +internal_font_number @!g; /*the number to return*/ +eight_bits @!a, @!b, @!c, @!d; /*byte variables*/ +four_quarters @!qw;scaled @!sw; /*accumulators*/ +int @!bch_label; /*left boundary start location, or infinity*/ +int @!bchar; /*right boundary character, or 256*/ +scaled @!z; /*the design size or the ``at'' size*/ +int @!alpha;int @!beta; + /*auxiliary quantities used in fixed-point multiplication*/ +g=null_font;@/ +@<Read and check the font data; |abort| if the \.{TFM} file is malformed; if there's +no room for this font, say so and |goto done|; otherwise |incr(font_ptr)| and |goto +done|@>; +bad_tfm: @<Report that the font won't be loaded@>; +done: if (file_opened) b_close(&tfm_file); +return g; +} + +@ There are programs called \.{TFtoPL} and \.{PLtoTF} that convert +between the \.{TFM} format and a symbolic property-list format +that can be easily edited. These programs contain extensive +diagnostic information, so \TeX\ does not have to bother giving +precise details about why it rejects a particular \.{TFM} file. +@.TFtoPL@> @.PLtoTF@> + +@d start_font_error_message print_err("Font ");sprint_cs(u); + print_char('=');print_file_name(nom, aire,""); + if (s >= 0) + {@+print(" at ");print_scaled(s);print("pt"); + } + else if (s!=-1000) + {@+print(" scaled ");print_int(-s); + } + +@<Report that the font won't be loaded@>= +start_font_error_message; +@.Font x=xx not loadable...@> +if (file_opened) print(" not loadable: Bad metric (TFM) file"); +else print(" not loadable: Metric (TFM) file not found"); +help5("I wasn't able to read the size data for this font,",@/ +"so I will ignore the font specification.",@/ +"[Wizards can fix TFM files using TFtoPL/PLtoTF.]",@/ +"You might try inserting a different font spec;",@/ +"e.g., type `I\\font<same font id>=<substitute font name>'."); +error() + +@ @<Read and check...@>= +@<Open |tfm_file| for input@>; +@<Read the {\.{TFM}} size fields@>; +@<Use size fields to allocate font information@>; +@<Read the {\.{TFM}} header@>; +@<Read character data@>; +@<Read box dimensions@>; +@<Read ligature/kern program@>; +@<Read extensible character recipes@>; +@<Read font parameters@>; +@<Make final adjustments and |goto done|@>@; + +@ @<Open |tfm_file| for input@>= +file_opened=false; +pack_file_name(nom, "",".tfm"); /* k\TeX\ */ +if (!b_open_in(&tfm_file)) abort; +file_opened=true + +@ Note: A malformed \.{TFM} file might be shorter than it claims to be; +thus |eof(tfm_file)| might be true when |read_font_info| refers to +|tfm_file.d| or when it says |get(tfm_file)|. If such circumstances +cause system error messages, you will have to defeat them somehow, +for example by defining |fget| to be `\ignorespaces|{@+get(tfm_file);| +|if (eof(tfm_file)) abort;} |\unskip'. +@^system dependencies@> + +@d fget get(tfm_file) +@d fbyte tfm_file.d +@d read_sixteen(A) {@+A=fbyte; + if (A > 127) abort; + fget;A=A*0400+fbyte; + } +@d store_four_quarters(A) {@+fget;a=fbyte;qw.b0=qi(a); + fget;b=fbyte;qw.b1=qi(b); + fget;c=fbyte;qw.b2=qi(c); + fget;d=fbyte;qw.b3=qi(d); + A=qw; + } + +@ @<Read the {\.{TFM}} size fields@>= +{@+read_sixteen(lf); +fget;read_sixteen(lh); +fget;read_sixteen(bc); +fget;read_sixteen(ec); +if ((bc > ec+1)||(ec > 255)) abort; +if (bc > 255) /*|bc==256| and |ec==255|*/ + {@+bc=1;ec=0; + } +fget;read_sixteen(nw); +fget;read_sixteen(nh); +fget;read_sixteen(nd); +fget;read_sixteen(ni); +fget;read_sixteen(nl); +fget;read_sixteen(nk); +fget;read_sixteen(ne); +fget;read_sixteen(np); +if (lf!=6+lh+(ec-bc+1)+nw+nh+nd+ni+nl+nk+ne+np) abort; +if ((nw==0)||(nh==0)||(nd==0)||(ni==0)) abort; +} + +@ The preliminary settings of the index-offset variables |char_base|, +|width_base|, |lig_kern_base|, |kern_base|, and |exten_base| will be +corrected later by subtracting |min_quarterword| from them; and we will +subtract 1 from |param_base| too. It's best to forget about such anomalies +until later. + +@<Use size fields to allocate font information@>= +lf=lf-6-lh; /*|lf| words should be loaded into |font_info|*/ +if (np < 7) lf=lf+7-np; /*at least seven parameters will appear*/ +if ((font_ptr==font_max)||(fmem_ptr+lf > font_mem_size)) + @<Apologize for not loading the font, |goto done|@>; +f=font_ptr+1; +char_base[f]=fmem_ptr-bc; +width_base[f]=char_base[f]+ec+1; +height_base[f]=width_base[f]+nw; +depth_base[f]=height_base[f]+nh; +italic_base[f]=depth_base[f]+nd; +lig_kern_base[f]=italic_base[f]+ni; +kern_base[f]=lig_kern_base[f]+nl-kern_base_offset; +exten_base[f]=kern_base[f]+kern_base_offset+nk; +param_base[f]=exten_base[f]+ne + +@ @<Apologize for not loading...@>= +{@+start_font_error_message; +print(" not loaded: Not enough room left"); +@.Font x=xx not loaded...@> +help4("I'm afraid I won't be able to make use of this font,",@/ +"because my memory for character-size data is too small.",@/ +"If you're really stuck, ask a wizard to enlarge me.",@/ +"Or maybe try `I\\font<same font id>=<name of loaded font>'."); +error();goto done; +} + +@ Only the first two words of the header are needed by \TeX82. + +@<Read the {\.{TFM}} header@>= +{@+if (lh < 2) abort; +store_four_quarters(font_check[f]); +fget;read_sixteen(z); /*this rejects a negative design size*/ +fget;z=z*0400+fbyte;fget;z=(z*020)+(fbyte/020); +if (z < unity) abort; +while (lh > 2) + {@+fget;fget;fget;fget;decr(lh); /*ignore the rest of the header*/ + } +font_dsize[f]=z; +if (s!=-1000) + if (s >= 0) z=s; + else z=xn_over_d(z,-s, 1000); +font_size[f]=z; +} + +@ @<Read character data@>= +for (k=fmem_ptr; k<=width_base[f]-1; k++) + {@+store_four_quarters(font_info[k].qqqq); + if ((a >= nw)||(b/020 >= nh)||(b%020 >= nd)|| + (c/4 >= ni)) abort; + switch (c%4) { + case lig_tag: if (d >= nl) abort;@+break; + case ext_tag: if (d >= ne) abort;@+break; + case list_tag: @<Check for charlist cycle@>@;@+break; + default:do_nothing; /*|no_tag|*/ + } + } + +@ We want to make sure that there is no cycle of characters linked together +by |list_tag| entries, since such a cycle would get \TeX\ into an endless +loop. If such a cycle exists, the routine here detects it when processing +the largest character code in the cycle. + +@d check_byte_range(A) {@+if ((A < bc)||(A > ec)) abort;@+} +@d current_character_being_worked_on k+bc-fmem_ptr + +@<Check for charlist cycle@>= +{@+check_byte_range(d); +while (d < current_character_being_worked_on) + {@+qw=char_info(f, d); + /*N.B.: not |qi(d)|, since |char_base[f]| hasn't been adjusted yet*/ + if (char_tag(qw)!=list_tag) goto not_found; + d=qo(rem_byte(qw)); /*next character on the list*/ + } +if (d==current_character_being_worked_on) abort; /*yes, there's a cycle*/ +not_found: ;} + +@ A |fix_word| whose four bytes are $(a,b,c,d)$ from left to right represents +the number +$$x=\left\{\vcenter{\halign{$#$,\hfil\qquad&if $#$\hfil\cr +b\cdot2^{-4}+c\cdot2^{-12}+d\cdot2^{-20}&a=0;\cr +-16+b\cdot2^{-4}+c\cdot2^{-12}+d\cdot2^{-20}&a=255.\cr}}\right.$$ +(No other choices of |a| are allowed, since the magnitude of a number in +design-size units must be less than 16.) We want to multiply this +quantity by the integer~|z|, which is known to be less than $2^{27}$. +If $|z|<2^{23}$, the individual multiplications $b\cdot z$, +$c\cdot z$, $d\cdot z$ cannot overflow; otherwise we will divide |z| by 2, +4, 8, or 16, to obtain a multiplier less than $2^{23}$, and we can +compensate for this later. If |z| has thereby been replaced by +$|z|^\prime=|z|/2^e$, let $\beta=2^{4-e}$; we shall compute +$$\lfloor(b+c\cdot2^{-8}+d\cdot2^{-16})\,z^\prime/\beta\rfloor$$ +if $a=0$, or the same quantity minus $\alpha=2^{4+e}z^\prime$ if $a=255$. +This calculation must be done exactly, in order to guarantee portability +of \TeX\ between computers. + +@d store_scaled(A) {@+fget;a=fbyte;fget;b=fbyte; + fget;c=fbyte;fget;d=fbyte;@/ + sw=(((((d*z)/0400)+(c*z))/0400)+(b*z))/beta; + if (a==0) A=sw;@+else if (a==255) A=sw-alpha;@+else abort; + } + +@<Read box dimensions@>= +{@+@<Replace |z| by $|z|^\prime$ and compute $\alpha,\beta$@>; +for (k=width_base[f]; k<=lig_kern_base[f]-1; k++) + store_scaled(font_info[k].sc); +if (font_info[width_base[f]].sc!=0) abort; /*\\{width}[0] must be zero*/ +if (font_info[height_base[f]].sc!=0) abort; /*\\{height}[0] must be zero*/ +if (font_info[depth_base[f]].sc!=0) abort; /*\\{depth}[0] must be zero*/ +if (font_info[italic_base[f]].sc!=0) abort; /*\\{italic}[0] must be zero*/ +} + +@ @<Replace |z|...@>= +{@+alpha=16; +while (z >= 040000000) + {@+z=z/2;alpha=alpha+alpha; + } +beta=256/alpha;alpha=alpha*z; +} + +@ @d check_existence(A) @t@>@;@/ + {@+check_byte_range(A); + qw=char_info(f, A); /*N.B.: not |qi(A)|*/ + if (!char_exists(qw)) abort; + } + +@<Read ligature/kern program@>= +bch_label=077777;bchar=256; +if (nl > 0) + {@+for (k=lig_kern_base[f]; k<=kern_base[f]+kern_base_offset-1; k++) + {@+store_four_quarters(font_info[k].qqqq); + if (a > 128) + {@+if (256*c+d >= nl) abort; + if (a==255) if (k==lig_kern_base[f]) bchar=b; + } + else{@+if (b!=bchar) check_existence(b); + if (c < 128) check_existence(d)@; /*check ligature*/ + else if (256*(c-128)+d >= nk) abort; /*check kern*/ + if (a < 128) if (k-lig_kern_base[f]+a+1 >= nl) abort; + } + } + if (a==255) bch_label=256*c+d; + } +for (k=kern_base[f]+kern_base_offset; k<=exten_base[f]-1; k++) + store_scaled(font_info[k].sc); + +@ @<Read extensible character recipes@>= +for (k=exten_base[f]; k<=param_base[f]-1; k++) + {@+store_four_quarters(font_info[k].qqqq); + if (a!=0) check_existence(a); + if (b!=0) check_existence(b); + if (c!=0) check_existence(c); + check_existence(d); + } + +@ We check to see that the \.{TFM} file doesn't end prematurely; but +no error message is given for files having more than |lf| words. + +@<Read font parameters@>= +{@+for (k=1; k<=np; k++) + if (k==1) /*the |slant| parameter is a pure number*/ + {@+fget;sw=fbyte;if (sw > 127) sw=sw-256; + fget;sw=sw*0400+fbyte;fget;sw=sw*0400+fbyte; + fget;font_info[param_base[f]].sc= + (sw*020)+(fbyte/020); + } + else store_scaled(font_info[param_base[f]+k-1].sc); +if (eof(tfm_file)) abort; +for (k=np+1; k<=7; k++) font_info[param_base[f]+k-1].sc=0; +} + +@ Now to wrap it up, we have checked all the necessary things about the \.{TFM} +file, and all we need to do is put the finishing touches on the data for +the new font. + +@d adjust(A) A[f]=qo(A[f]) + /*correct for the excess |min_quarterword| that was added*/ + +@<Make final adjustments...@>= +if (np >= 7) font_params[f]=np;@+else font_params[f]=7; +hyphen_char[f]=default_hyphen_char;skew_char[f]=default_skew_char; +if (bch_label < nl) bchar_label[f]=bch_label+lig_kern_base[f]; +else bchar_label[f]=non_address; +font_bchar[f]=qi(bchar); +font_false_bchar[f]=qi(bchar); +if (bchar <= ec) if (bchar >= bc) + {@+qw=char_info(f, bchar); /*N.B.: not |qi(bchar)|*/ + if (char_exists(qw)) font_false_bchar[f]=non_char; + } +font_name[f]=nom; +font_area[f]=s_no(aire); +font_bc[f]=bc;font_ec[f]=ec;font_glue[f]=null; +adjust(char_base);adjust(width_base);adjust(lig_kern_base); +adjust(kern_base);adjust(exten_base); +decr(param_base[f]); +fmem_ptr=fmem_ptr+lf;font_ptr=f;g=f;goto done + +@ Before we forget about the format of these tables, let's deal with two +of \TeX's basic scanning routines related to font information. + +@<Declare procedures that scan font-related stuff@>= +static void scan_font_ident(void) +{@+internal_font_number f; +halfword @!m; +@<Get the next non-blank non-call...@>; +if (cur_cmd==def_font) f=cur_font; +else if (cur_cmd==set_font) f=cur_chr; +else if (cur_cmd==def_family) + {@+m=cur_chr;scan_four_bit_int();f=equiv(m+cur_val); + } +else{@+print_err("Missing font identifier"); +@.Missing font identifier@> + help2("I was looking for a control sequence whose",@/ + "current meaning has been defined by \\font."); + back_error();f=null_font; + } +cur_val=f; +} + +@ The following routine is used to implement `\.{\\fontdimen} |n| |f|'. +The boolean parameter |writing| is set |true| if the calling program +intends to change the parameter value. + +@<Declare procedures that scan font-related stuff@>= +static void find_font_dimen(bool @!writing) + /*sets |cur_val| to |font_info| location*/ +{@+internal_font_number f; +int @!n; /*the parameter number*/ +scan_int();n=cur_val;scan_font_ident();f=cur_val; +if (n <= 0) cur_val=fmem_ptr; +else{@+if (writing&&(n <= space_shrink_code)&&@| + (n >= space_code)&&(font_glue[f]!=null)) + {@+delete_glue_ref(font_glue[f]); + font_glue[f]=null; + } + if (n > font_params[f]) + if (f < font_ptr) cur_val=fmem_ptr; + else@<Increase the number of parameters in the last font@>@; + else cur_val=n+param_base[f]; + } +@<Issue an error message if |cur_val=fmem_ptr|@>; +} + +@ @<Issue an error message if |cur_val=fmem_ptr|@>= +if (cur_val==fmem_ptr) + {@+print_err("Font ");printn_esc(font_id_text(f)); + print(" has only ");print_int(font_params[f]); + print(" fontdimen parameters"); +@.Font x has only...@> + help2("To increase the number of font parameters, you must",@/ + "use \\fontdimen immediately after the \\font is loaded."); + error(); + } + +@ @<Increase the number of parameters...@>= +{@+@/do@+{if (fmem_ptr==font_mem_size) + overflow("font memory", font_mem_size); +@:TeX capacity exceeded font memory}{\quad font memory@> +font_info[fmem_ptr].sc=0;incr(fmem_ptr);incr(font_params[f]); +}@+ while (!(n==font_params[f])); +cur_val=fmem_ptr-1; /*this equals |param_base[f]+font_params[f]|*/ +} + +@ When \TeX\ wants to typeset a character that doesn't exist, the +character node is not created; thus the output routine can assume +that characters exist when it sees them. The following procedure +prints a warning message unless the user has suppressed it. + +@p static void char_warning(internal_font_number @!f, eight_bits @!c) +{@+int old_setting; /*saved value of |tracing_online|*/ +if (tracing_lost_chars > 0) + {@+old_setting=tracing_online; + if (eTeX_ex&&(tracing_lost_chars > 1)) tracing_online=1; + {@+begin_diagnostic(); + print_nl("Missing character: There is no "); +@.Missing character@> + print_ASCII(c);print(" in font "); + slow_print(font_name[f]);print_char('!');end_diagnostic(false); + } + tracing_online=old_setting; + } +} + +@ Here is a function that returns a pointer to a character node for a +given character in a given font. If that character doesn't exist, +|null| is returned instead. + +@p pointer new_character(internal_font_number @!f, eight_bits @!c) +{@+ +pointer p; /*newly allocated node*/ +if (font_bc[f] <= c) if (font_ec[f] >= c) + if (char_exists(char_info(f, qi(c)))) + {@+p=get_avail();font(p)=f;character(p)=qi(c); + return p; + } +char_warning(f, c); +return null; +} + +@* Device-independent file format. +The most important output produced by a run of \TeX\ is the ``device +independent'' (\.{DVI}) file that specifies where characters and rules +are to appear on printed pages. The form of these files was designed by +David R. Fuchs in 1979. Almost any reasonable typesetting device can be +@^Fuchs, David Raymond@> +@:DVI\_files}{\.{DVI} files@> +driven by a program that takes \.{DVI} files as input, and dozens of such +\.{DVI}-to-whatever programs have been written. Thus, it is possible to +print the output of \TeX\ on many different kinds of equipment, using \TeX\ +as a device-independent ``front end.'' + +A \.{DVI} file is a stream of 8-bit bytes, which may be regarded as a +series of commands in a machine-like language. The first byte of each command +is the operation code, and this code is followed by zero or more bytes +that provide parameters to the command. The parameters themselves may consist +of several consecutive bytes; for example, the `|set_rule|' command has two +parameters, each of which is four bytes long. Parameters are usually +regarded as nonnegative integers; but four-byte-long parameters, +and shorter parameters that denote distances, can be +either positive or negative. Such parameters are given in two's complement +notation. For example, a two-byte-long distance parameter has a value between +$-2^{15}$ and $2^{15}-1$. As in \.{TFM} files, numbers that occupy +more than one byte position appear in BigEndian order. + +A \.{DVI} file consists of a ``preamble,'' followed by a sequence of one +or more ``pages,'' followed by a ``postamble.'' The preamble is simply a +|pre| command, with its parameters that define the dimensions used in the +file; this must come first. Each ``page'' consists of a |bop| command, +followed by any number of other commands that tell where characters are to +be placed on a physical page, followed by an |eop| command. The pages +appear in the order that \TeX\ generated them. If we ignore |nop| commands +and \\{fnt\_def} commands (which are allowed between any two commands in +the file), each |eop| command is immediately followed by a |bop| command, +or by a |post| command; in the latter case, there are no more pages in the +file, and the remaining bytes form the postamble. Further details about +the postamble will be explained later. + +Some parameters in \.{DVI} commands are ``pointers.'' These are four-byte +quantities that give the location number of some other byte in the file; +the first byte is number~0, then comes number~1, and so on. For example, +one of the parameters of a |bop| command points to the previous |bop|; +this makes it feasible to read the pages in backwards order, in case the +results are being directed to a device that stacks its output face up. +Suppose the preamble of a \.{DVI} file occupies bytes 0 to 99. Now if the +first page occupies bytes 100 to 999, say, and if the second +page occupies bytes 1000 to 1999, then the |bop| that starts in byte 1000 +points to 100 and the |bop| that starts in byte 2000 points to 1000. (The +very first |bop|, i.e., the one starting in byte 100, has a pointer of~$-1$.) + +@ The \.{DVI} format is intended to be both compact and easily interpreted +by a machine. Compactness is achieved by making most of the information +implicit instead of explicit. When a \.{DVI}-reading program reads the +commands for a page, it keeps track of several quantities: (a)~The current +font |f| is an integer; this value is changed only +by \\{fnt} and \\{fnt\_num} commands. (b)~The current position on the page +is given by two numbers called the horizontal and vertical coordinates, +|h| and |v|. Both coordinates are zero at the upper left corner of the page; +moving to the right corresponds to increasing the horizontal coordinate, and +moving down corresponds to increasing the vertical coordinate. Thus, the +coordinates are essentially Cartesian, except that vertical directions are +flipped; the Cartesian version of |(h, v)| would be |(h,-v)|. (c)~The +current spacing amounts are given by four numbers |w|, |x|, |y|, and |z|, +where |w| and~|x| are used for horizontal spacing and where |y| and~|z| +are used for vertical spacing. (d)~There is a stack containing +|(h, v, w, x, y, z)| values; the \.{DVI} commands |push| and |pop| are used to +change the current level of operation. Note that the current font~|f| is +not pushed and popped; the stack contains only information about +positioning. + +The values of |h|, |v|, |w|, |x|, |y|, and |z| are signed integers having up +to 32 bits, including the sign. Since they represent physical distances, +there is a small unit of measurement such that increasing |h| by~1 means +moving a certain tiny distance to the right. The actual unit of +measurement is variable, as explained below; \TeX\ sets things up so that +its \.{DVI} output is in sp units, i.e., scaled points, in agreement with +all the |scaled| dimensions in \TeX's data structures. + +@ Here is a list of all the commands that may appear in a \.{DVI} file. Each +command is specified by its symbolic name (e.g., |bop|), its opcode byte +(e.g., 139), and its parameters (if any). The parameters are followed +by a bracketed number telling how many bytes they occupy; for example, +`|p[4]|' means that parameter |p| is four bytes long. + +\yskip\hang|set_char_0| 0. Typeset character number~0 from font~|f| +such that the reference point of the character is at |(h, v)|. Then +increase |h| by the width of that character. Note that a character may +have zero or negative width, so one cannot be sure that |h| will advance +after this command; but |h| usually does increase. + +\yskip\hang\\{set\_char\_1} through \\{set\_char\_127} (opcodes 1 to 127). +Do the operations of |set_char_0|; but use the character whose number +matches the opcode, instead of character~0. + +\yskip\hang|set1| 128 |c[1]|. Same as |set_char_0|, except that character +number~|c| is typeset. \TeX82 uses this command for characters in the +range |128 <= c < 256|. + +\yskip\hang|@!set2| 129 |c[2]|. Same as |set1|, except that |c|~is two +bytes long, so it is in the range |0 <= c < 65536|. \TeX82 never uses this +command, but it should come in handy for extensions of \TeX\ that deal +with oriental languages. +@^oriental characters@>@^Chinese characters@>@^Japanese characters@> + +\yskip\hang|@!set3| 130 |c[3]|. Same as |set1|, except that |c|~is three +bytes long, so it can be as large as $2^{24}-1$. Not even the Chinese +language has this many characters, but this command might prove useful +in some yet unforeseen extension. + +\yskip\hang|@!set4| 131 |c[4]|. Same as |set1|, except that |c|~is four +bytes long. Imagine that. + +\yskip\hang|set_rule| 132 |a[4]| |b[4]|. Typeset a solid black rectangle +of height~|a| and width~|b|, with its bottom left corner at |(h, v)|. Then +set |h=h+b|. If either |a <= 0| or |b <= 0|, nothing should be typeset. Note +that if |b < 0|, the value of |h| will decrease even though nothing else happens. +See below for details about how to typeset rules so that consistency with +\MF\ is guaranteed. + +\yskip\hang|@!put1| 133 |c[1]|. Typeset character number~|c| from font~|f| +such that the reference point of the character is at |(h, v)|. (The `put' +commands are exactly like the `set' commands, except that they simply put out a +character or a rule without moving the reference point afterwards.) + +\yskip\hang|@!put2| 134 |c[2]|. Same as |set2|, except that |h| is not changed. + +\yskip\hang|@!put3| 135 |c[3]|. Same as |set3|, except that |h| is not changed. + +\yskip\hang|@!put4| 136 |c[4]|. Same as |set4|, except that |h| is not changed. + +\yskip\hang|put_rule| 137 |a[4]| |b[4]|. Same as |set_rule|, except that +|h| is not changed. + +\yskip\hang|nop| 138. No operation, do nothing. Any number of |nop|'s +may occur between \.{DVI} commands, but a |nop| cannot be inserted between +a command and its parameters or between two parameters. + +\yskip\hang|bop| 139 $c_0[4]$ $c_1[4]$ $\ldots$ $c_9[4]$ $p[4]$. Beginning +of a page: Set |(h, v, w, x, y, z)=(0, 0, 0, 0, 0, 0)| and set the stack empty. Set +the current font |f| to an undefined value. The ten $c_i$ parameters hold +the values of \.{\\count0} $\ldots$ \.{\\count9} in \TeX\ at the time +\.{\\shipout} was invoked for this page; they can be used to identify +pages, if a user wants to print only part of a \.{DVI} file. The parameter +|p| points to the previous |bop| in the file; the first +|bop| has $p=-1$. + +\yskip\hang|eop| 140. End of page: Print what you have read since the +previous |bop|. At this point the stack should be empty. (The \.{DVI}-reading +programs that drive most output devices will have kept a buffer of the +material that appears on the page that has just ended. This material is +largely, but not entirely, in order by |v| coordinate and (for fixed |v|) by +|h|~coordinate; so it usually needs to be sorted into some order that is +appropriate for the device in question.) + +\yskip\hang|push| 141. Push the current values of |(h, v, w, x, y, z)| onto the +top of the stack; do not change any of these values. Note that |f| is +not pushed. + +\yskip\hang|pop| 142. Pop the top six values off of the stack and assign +them respectively to |(h, v, w, x, y, z)|. The number of pops should never +exceed the number of pushes, since it would be highly embarrassing if the +stack were empty at the time of a |pop| command. + +\yskip\hang|right1| 143 |b[1]|. Set |h=h+b|, i.e., move right |b| units. +The parameter is a signed number in two's complement notation, |-128 <= b < 128|; +if |b < 0|, the reference point moves left. + +\yskip\hang|right2| 144 |b[2]|. Same as |right1|, except that |b| is a +two-byte quantity in the range |-32768 <= b < 32768|. + +\yskip\hang|right3| 145 |b[3]|. Same as |right1|, except that |b| is a +three-byte quantity in the range |@t$-2^{23}$@> <= b < @t$2^{23}$@>|. + +\yskip\hang|right4| 146 |b[4]|. Same as |right1|, except that |b| is a +four-byte quantity in the range |@t$-2^{31}$@> <= b < @t$2^{31}$@>|. + +\yskip\hang|w0| 147. Set |h=h+w|; i.e., move right |w| units. With luck, +this parameterless command will usually suffice, because the same kind of motion +will occur several times in succession; the following commands explain how +|w| gets particular values. + +\yskip\hang|w1| 148 |b[1]|. Set |w=b| and |h=h+b|. The value of |b| is a +signed quantity in two's complement notation, |-128 <= b < 128|. This command +changes the current |w|~spacing and moves right by |b|. + +\yskip\hang|@!w2| 149 |b[2]|. Same as |w1|, but |b| is two bytes long, +|-32768 <= b < 32768|. + +\yskip\hang|@!w3| 150 |b[3]|. Same as |w1|, but |b| is three bytes long, +|@t$-2^{23}$@> <= b < @t$2^{23}$@>|. + +\yskip\hang|@!w4| 151 |b[4]|. Same as |w1|, but |b| is four bytes long, +|@t$-2^{31}$@> <= b < @t$2^{31}$@>|. + +\yskip\hang|x0| 152. Set |h=h+x|; i.e., move right |x| units. The `|x|' +commands are like the `|w|' commands except that they involve |x| instead +of |w|. + +\yskip\hang|x1| 153 |b[1]|. Set |x=b| and |h=h+b|. The value of |b| is a +signed quantity in two's complement notation, |-128 <= b < 128|. This command +changes the current |x|~spacing and moves right by |b|. + +\yskip\hang|@!x2| 154 |b[2]|. Same as |x1|, but |b| is two bytes long, +|-32768 <= b < 32768|. + +\yskip\hang|@!x3| 155 |b[3]|. Same as |x1|, but |b| is three bytes long, +|@t$-2^{23}$@> <= b < @t$2^{23}$@>|. + +\yskip\hang|@!x4| 156 |b[4]|. Same as |x1|, but |b| is four bytes long, +|@t$-2^{31}$@> <= b < @t$2^{31}$@>|. + +\yskip\hang|down1| 157 |a[1]|. Set |v=v+a|, i.e., move down |a| units. +The parameter is a signed number in two's complement notation, |-128 <= a < 128|; +if |a < 0|, the reference point moves up. + +\yskip\hang|@!down2| 158 |a[2]|. Same as |down1|, except that |a| is a +two-byte quantity in the range |-32768 <= a < 32768|. + +\yskip\hang|@!down3| 159 |a[3]|. Same as |down1|, except that |a| is a +three-byte quantity in the range |@t$-2^{23}$@> <= a < @t$2^{23}$@>|. + +\yskip\hang|@!down4| 160 |a[4]|. Same as |down1|, except that |a| is a +four-byte quantity in the range |@t$-2^{31}$@> <= a < @t$2^{31}$@>|. + +\yskip\hang|y0| 161. Set |v=v+y|; i.e., move down |y| units. With luck, +this parameterless command will usually suffice, because the same kind of motion +will occur several times in succession; the following commands explain how +|y| gets particular values. + +\yskip\hang|y1| 162 |a[1]|. Set |y=a| and |v=v+a|. The value of |a| is a +signed quantity in two's complement notation, |-128 <= a < 128|. This command +changes the current |y|~spacing and moves down by |a|. + +\yskip\hang|@!y2| 163 |a[2]|. Same as |y1|, but |a| is two bytes long, +|-32768 <= a < 32768|. + +\yskip\hang|@!y3| 164 |a[3]|. Same as |y1|, but |a| is three bytes long, +|@t$-2^{23}$@> <= a < @t$2^{23}$@>|. + +\yskip\hang|@!y4| 165 |a[4]|. Same as |y1|, but |a| is four bytes long, +|@t$-2^{31}$@> <= a < @t$2^{31}$@>|. + +\yskip\hang|z0| 166. Set |v=v+z|; i.e., move down |z| units. The `|z|' commands +are like the `|y|' commands except that they involve |z| instead of |y|. + +\yskip\hang|z1| 167 |a[1]|. Set |z=a| and |v=v+a|. The value of |a| is a +signed quantity in two's complement notation, |-128 <= a < 128|. This command +changes the current |z|~spacing and moves down by |a|. + +\yskip\hang|@!z2| 168 |a[2]|. Same as |z1|, but |a| is two bytes long, +|-32768 <= a < 32768|. + +\yskip\hang|@!z3| 169 |a[3]|. Same as |z1|, but |a| is three bytes long, +|@t$-2^{23}$@> <= a < @t$2^{23}$@>|. + +\yskip\hang|@!z4| 170 |a[4]|. Same as |z1|, but |a| is four bytes long, +|@t$-2^{31}$@> <= a < @t$2^{31}$@>|. + +\yskip\hang|fnt_num_0| 171. Set |f=0|. Font 0 must previously have been +defined by a \\{fnt\_def} instruction, as explained below. + +\yskip\hang\\{fnt\_num\_1} through \\{fnt\_num\_63} (opcodes 172 to 234). Set +|f=1|, \dots, \hbox{|f=63|}, respectively. + +\yskip\hang|fnt1| 235 |k[1]|. Set |f=k|. \TeX82 uses this command for font +numbers in the range |64 <= k < 256|. + +\yskip\hang|@!fnt2| 236 |k[2]|. Same as |fnt1|, except that |k|~is two +bytes long, so it is in the range |0 <= k < 65536|. \TeX82 never generates this +command, but large font numbers may prove useful for specifications of +color or texture, or they may be used for special fonts that have fixed +numbers in some external coding scheme. + +\yskip\hang|@!fnt3| 237 |k[3]|. Same as |fnt1|, except that |k|~is three +bytes long, so it can be as large as $2^{24}-1$. + +\yskip\hang|@!fnt4| 238 |k[4]|. Same as |fnt1|, except that |k|~is four +bytes long; this is for the really big font numbers (and for the negative ones). + +\yskip\hang|xxx1| 239 |k[1]| |x[k]|. This command is undefined in +general; it functions as a $(k+2)$-byte |nop| unless special \.{DVI}-reading +programs are being used. \TeX82 generates |xxx1| when a short enough +\.{\\special} appears, setting |k| to the number of bytes being sent. It +is recommended that |x| be a string having the form of a keyword followed +by possible parameters relevant to that keyword. + +\yskip\hang|@!xxx2| 240 |k[2]| |x[k]|. Like |xxx1|, but |0 <= k < 65536|. + +\yskip\hang|@!xxx3| 241 |k[3]| |x[k]|. Like |xxx1|, but |0 <= k < @t$2^{24}$@>|. + +\yskip\hang|xxx4| 242 |k[4]| |x[k]|. Like |xxx1|, but |k| can be ridiculously +large. \TeX82 uses |xxx4| when sending a string of length 256 or more. + +\yskip\hang|fnt_def1| 243 |k[1]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|. +Define font |k|, where |0 <= k < 256|; font definitions will be explained shortly. + +\yskip\hang|@!fnt_def2| 244 |k[2]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|. +Define font |k|, where |0 <= k < 65536|. + +\yskip\hang|@!fnt_def3| 245 |k[3]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|. +Define font |k|, where |0 <= k < @t$2^{24}$@>|. + +\yskip\hang|@!fnt_def4| 246 |k[4]| |c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|. +Define font |k|, where |@t$-2^{31}$@> <= k < @t$2^{31}$@>|. + +\yskip\hang|pre| 247 |i[1]| |num[4]| |den[4]| |mag[4]| |k[1]| |x[k]|. +Beginning of the preamble; this must come at the very beginning of the +file. Parameters |i|, |num|, |den|, |mag|, |k|, and |x| are explained below. + +\yskip\hang|post| 248. Beginning of the postamble, see below. + +\yskip\hang|post_post| 249. Ending of the postamble, see below. + +\yskip\noindent Commands 250--255 are undefined at the present time. + +@ @d set_char_0 0 /*typeset character 0 and move right*/ +@d set1 128 /*typeset a character and move right*/ +@d set_rule 132 /*typeset a rule and move right*/ +@d put_rule 137 /*typeset a rule*/ +@d nop 138 /*no operation*/ +@d bop 139 /*beginning of page*/ +@d eop 140 /*ending of page*/ +@d push 141 /*save the current positions*/ +@d pop 142 /*restore previous positions*/ +@d right1 143 /*move right*/ +@d w0 147 /*move right by |w|*/ +@d w1 148 /*move right and set |w|*/ +@d x0 152 /*move right by |x|*/ +@d x1 153 /*move right and set |x|*/ +@d down1 157 /*move down*/ +@d y0 161 /*move down by |y|*/ +@d y1 162 /*move down and set |y|*/ +@d z0 166 /*move down by |z|*/ +@d z1 167 /*move down and set |z|*/ +@d fnt_num_0 171 /*set current font to 0*/ +@d fnt1 235 /*set current font*/ +@d xxx1 239 /*extension to \.{DVI} primitives*/ +@d xxx4 242 /*potentially long extension to \.{DVI} primitives*/ +@d fnt_def1 243 /*define the meaning of a font number*/ +@d pre 247 /*preamble*/ +@d post 248 /*postamble beginning*/ +@d post_post 249 /*postamble ending*/ + +@ The preamble contains basic information about the file as a whole. As +stated above, there are six parameters: +$$\hbox{|@!i[1]| |@!num[4]| |@!den[4]| |@!mag[4]| |@!k[1]| |@!x[k]|.}$$ +The |i| byte identifies \.{DVI} format; currently this byte is always set +to~2. (The value |i==3| is currently used for an extended format that +allows a mixture of right-to-left and left-to-right typesetting. +Some day we will set |i==4|, when \.{DVI} format makes another +incompatible change---perhaps in the year 2048.) + +The next two parameters, |num| and |den|, are positive integers that define +the units of measurement; they are the numerator and denominator of a +fraction by which all dimensions in the \.{DVI} file could be multiplied +in order to get lengths in units of $10^{-7}$ meters. Since $\rm 7227{pt} = +254{cm}$, and since \TeX\ works with scaled points where there are $2^{16}$ +sp in a point, \TeX\ sets +$|num|/|den|=(254\cdot10^5)/(7227\cdot2^{16})=25400000/473628672$. +@^sp@> + +The |mag| parameter is what \TeX\ calls \.{\\mag}, i.e., 1000 times the +desired magnification. The actual fraction by which dimensions are +multiplied is therefore $|mag|\cdot|num|/1000|den|$. Note that if a \TeX\ +source document does not call for any `\.{true}' dimensions, and if you +change it only by specifying a different \.{\\mag} setting, the \.{DVI} +file that \TeX\ creates will be completely unchanged except for the value +of |mag| in the preamble and postamble. (Fancy \.{DVI}-reading programs allow +users to override the |mag|~setting when a \.{DVI} file is being printed.) + +Finally, |k| and |x| allow the \.{DVI} writer to include a comment, which is not +interpreted further. The length of comment |x| is |k|, where |0 <= k < 256|. + +@d id_byte 2 /*identifies the kind of \.{DVI} files described here*/ + +@ Font definitions for a given font number |k| contain further parameters +$$\hbox{|c[4]| |s[4]| |d[4]| |a[1]| |l[1]| |n[a+l]|.}$$ +The four-byte value |c| is the check sum that \TeX\ found in the \.{TFM} +file for this font; |c| should match the check sum of the font found by +programs that read this \.{DVI} file. +@^check sum@> + +Parameter |s| contains a fixed-point scale factor that is applied to +the character widths in font |k|; font dimensions in \.{TFM} files and +other font files are relative to this quantity, which is called the +``at size'' elsewhere in this documentation. The value of |s| is +always positive and less than $2^{27}$. It is given in the same units +as the other \.{DVI} dimensions, i.e., in sp when \TeX82 has made the +file. Parameter |d| is similar to |s|; it is the ``design size,'' and +(like~|s|) it is given in \.{DVI} units. Thus, font |k| is to be used +at $|mag|\cdot s/1000d$ times its normal size. + +The remaining part of a font definition gives the external name of the font, +which is an ASCII string of length |a+l|. The number |a| is the length +of the ``area'' or directory, and |l| is the length of the font name itself; +the standard local system font area is supposed to be used when |a==0|. +The |n| field contains the area in its first |a| bytes. + +Font definitions must appear before the first use of a particular font number. +Once font |k| is defined, it must not be defined again; however, we +shall see below that font definitions appear in the postamble as well as +in the pages, so in this sense each font number is defined exactly twice, +if at all. Like |nop| commands, font definitions can +appear before the first |bop|, or between an |eop| and a |bop|. + +@ Sometimes it is desirable to make horizontal or vertical rules line up +precisely with certain features in characters of a font. It is possible to +guarantee the correct matching between \.{DVI} output and the characters +generated by \MF\ by adhering to the following principles: (1)~The \MF\ +characters should be positioned so that a bottom edge or left edge that is +supposed to line up with the bottom or left edge of a rule appears at the +reference point, i.e., in row~0 and column~0 of the \MF\ raster. This +ensures that the position of the rule will not be rounded differently when +the pixel size is not a perfect multiple of the units of measurement in +the \.{DVI} file. (2)~A typeset rule of height $a>0$ and width $b>0$ +should be equivalent to a \MF-generated character having black pixels in +precisely those raster positions whose \MF\ coordinates satisfy +|0 <= x < @t$\alpha$@>b| and |0 <= y < @t$\alpha$@>a|, where $\alpha$ is the number +of pixels per \.{DVI} unit. +@:METAFONT}{\MF@> +@^alignment of rules with characters@> +@^rules aligning with characters@> + +@ The last page in a \.{DVI} file is followed by `|post|'; this command +introduces the postamble, which summarizes important facts that \TeX\ has +accumulated about the file, making it possible to print subsets of the data +with reasonable efficiency. The postamble has the form +$$\vbox{\halign{\hbox{#\hfil}\cr + |post| |p[4]| |num[4]| |den[4]| |mag[4]| |l[4]| |u[4]| |s[2]| |t[2]|\cr + $\langle\,$font definitions$\,\rangle$\cr + |post_post| |q[4]| |i[1]| 223's$[{\G}4]$\cr}}$$ +Here |p| is a pointer to the final |bop| in the file. The next three +parameters, |num|, |den|, and |mag|, are duplicates of the quantities that +appeared in the preamble. + +Parameters |l| and |u| give respectively the height-plus-depth of the tallest +page and the width of the widest page, in the same units as other dimensions +of the file. These numbers might be used by a \.{DVI}-reading program to +position individual ``pages'' on large sheets of film or paper; however, +the standard convention for output on normal size paper is to position each +page so that the upper left-hand corner is exactly one inch from the left +and the top. Experience has shown that it is unwise to design \.{DVI}-to-printer +software that attempts cleverly to center the output; a fixed position of +the upper left corner is easiest for users to understand and to work with. +Therefore |l| and~|u| are often ignored. + +Parameter |s| is the maximum stack depth (i.e., the largest excess of +|push| commands over |pop| commands) needed to process this file. Then +comes |t|, the total number of pages (|bop| commands) present. + +The postamble continues with font definitions, which are any number of +\\{fnt\_def} commands as described above, possibly interspersed with |nop| +commands. Each font number that is used in the \.{DVI} file must be defined +exactly twice: Once before it is first selected by a \\{fnt} command, and once +in the postamble. + +@ The last part of the postamble, following the |post_post| byte that +signifies the end of the font definitions, contains |q|, a pointer to the +|post| command that started the postamble. An identification byte, |i|, +comes next; this currently equals~2, as in the preamble. + +The |i| byte is followed by four or more bytes that are all equal to +the decimal number 223 (i.e., 0337 in octal). \TeX\ puts out four to seven of +these trailing bytes, until the total length of the file is a multiple of +four bytes, since this works out best on machines that pack four bytes per +word; but any number of 223's is allowed, as long as there are at least four +of them. In effect, 223 is a sort of signature that is added at the very end. +@^Fuchs, David Raymond@> + +This curious way to finish off a \.{DVI} file makes it feasible for +\.{DVI}-reading programs to find the postamble first, on most computers, +even though \TeX\ wants to write the postamble last. Most operating +systems permit random access to individual words or bytes of a file, so +the \.{DVI} reader can start at the end and skip backwards over the 223's +until finding the identification byte. Then it can back up four bytes, read +|q|, and move to byte |q| of the file. This byte should, of course, +contain the value 248 (|post|); now the postamble can be read, so the +\.{DVI} reader can discover all the information needed for typesetting the +pages. Note that it is also possible to skip through the \.{DVI} file at +reasonably high speed to locate a particular page, if that proves +desirable. This saves a lot of time, since \.{DVI} files used in production +jobs tend to be large. + +Unfortunately, however, standard \PASCAL\ does not include the ability to +@^system dependencies@> +access a random position in a file, or even to determine the length of a file. +Almost all systems nowadays provide the necessary capabilities, so \.{DVI} +format has been designed to work most efficiently with modern operating systems. +But if \.{DVI} files have to be processed under the restrictions of standard +\PASCAL, one can simply read them from front to back, since the necessary +header information is present in the preamble and in the font definitions. +(The |l| and |u| and |s| and |t| parameters, which appear only in the +postamble, are ``frills'' that are handy but not absolutely necessary.) + +@* Shipping pages out. +After considering \TeX's eyes and stomach, we come now to the bowels. +@^bowels@> + +The |ship_out| procedure is given a pointer to a box; its mission is +to describe that box in \.{DVI} form, outputting a ``page'' to |dvi_file|. +The \.{DVI} coordinates $(h,v)=(0,0)$ should correspond to the upper left +corner of the box being shipped. + +Since boxes can be inside of boxes inside of boxes, the main work of +|ship_out| is done by two mutually recursive routines, |hlist_out| +and |vlist_out|, which traverse the hlists and vlists inside of horizontal +and vertical boxes. + +As individual pages are being processed, we need to accumulate +information about the entire set of pages, since such statistics must be +reported in the postamble. The global variables |total_pages|, |max_v|, +|max_h|, |max_push|, and |last_bop| are used to record this information. + +The variable |doing_leaders| is |true| while leaders are being output. +The variable |dead_cycles| contains the number of times an output routine +has been initiated since the last |ship_out|. + +A few additional global variables are also defined here for use in +|vlist_out| and |hlist_out|. They could have been local variables, but +that would waste stack space when boxes are deeply nested, since the +values of these variables are not needed during recursive calls. +@^recursion@> + +@<Glob...@>= +static int @!total_pages; /*the number of pages that have been shipped out*/ +static scaled @!max_v; /*maximum height-plus-depth of pages shipped so far*/ +static scaled @!max_h; /*maximum width of pages shipped so far*/ +static int @!max_push; /*deepest nesting of |push| commands encountered so far*/ +static int @!last_bop; /*location of previous |bop| in the \.{DVI} output*/ +static int @!dead_cycles; /*recent outputs that didn't ship anything out*/ +bool @!doing_leaders; /*are we inside a leader box?*/ +@# +static quarterword @!c, @!f; /*character and font in current |char_node|*/ +static scaled @!rule_ht, @!rule_dp, @!rule_wd; /*size of current rule being output*/ +static pointer @!g; /*current glue specification*/ +static int @!lq, @!lr; /*quantities used in calculations for leaders*/ + +@ @<Set init...@>= +total_pages=0;max_v=0;max_h=0;max_push=0;last_bop=-1; +doing_leaders=false;dead_cycles=0;cur_s=-1; + +@ The \.{DVI} bytes are output to a buffer instead of being written directly +to the output file. This makes it possible to reduce the overhead of +subroutine calls, thereby measurably speeding up the computation, since +output of \.{DVI} bytes is part of \TeX's inner loop. And it has another +advantage as well, since we can change instructions in the buffer in order to +make the output more compact. For example, a `|down2|' command can be +changed to a `|y2|', thereby making a subsequent `|y0|' command possible, +saving two bytes. + +The output buffer is divided into two parts of equal size; the bytes found +in |dvi_buf[0 dotdot half_buf-1]| constitute the first half, and those in +|dvi_buf[half_buf dotdot dvi_buf_size-1]| constitute the second. The global +variable |dvi_ptr| points to the position that will receive the next +output byte. When |dvi_ptr| reaches |dvi_limit|, which is always equal +to one of the two values |half_buf| or |dvi_buf_size|, the half buffer that +is about to be invaded next is sent to the output and |dvi_limit| is +changed to its other value. Thus, there is always at least a half buffer's +worth of information present, except at the very beginning of the job. + +Bytes of the \.{DVI} file are numbered sequentially starting with 0; +the next byte to be generated will be number |dvi_offset+dvi_ptr|. +A byte is present in the buffer only if its number is | >= dvi_gone|. + +@<Types...@>= +typedef int16_t dvi_index; /*an index into the output buffer*/ + +@ Some systems may find it more efficient to make |dvi_buf| a || +array, since output of four bytes at once may be facilitated. +@^system dependencies@> + +@<Glob...@>= +static eight_bits @!dvi_buf[dvi_buf_size+1]; /*buffer for \.{DVI} output*/ +static dvi_index @!half_buf; /*half of |dvi_buf_size|*/ +static dvi_index @!dvi_limit; /*end of the current half buffer*/ +static dvi_index @!dvi_ptr; /*the next available buffer address*/ +static int @!dvi_offset; /*|dvi_buf_size| times the number of times the + output buffer has been fully emptied*/ +static int @!dvi_gone; /*the number of bytes already output to |dvi_file|*/ + +@ Initially the buffer is all in one piece; we will output half of it only +after it first fills up. + +@<Set init...@>= +half_buf=dvi_buf_size/2;dvi_limit=dvi_buf_size;dvi_ptr=0; +dvi_offset=0;dvi_gone=0; + +@ The actual output of |dvi_buf[a dotdot b]| to |dvi_file| is performed by calling +|write_dvi(a, b)|. For best results, this procedure should be optimized to +run as fast as possible on each particular system, since it is part of +\TeX's inner loop. It is safe to assume that |a| and |b+1| will both be +multiples of 4 when |write_dvi(a, b)| is called; therefore it is possible on +many machines to use efficient methods to pack four bytes per word and to +output an array of words with one system call. +@^system dependencies@> +@^inner loop@> +@^defecation@> + +@p static void write_dvi(dvi_index @!a, dvi_index @!b) +{@+int k; +for (k=a; k<=b; k++) pascal_write(dvi_file, "%c", dvi_buf[k]); +} + +@ To put a byte in the buffer without paying the cost of invoking a procedure +each time, we use the macro |dvi_out|. + +@d dvi_out(A) @+{@+dvi_buf[dvi_ptr]=A;incr(dvi_ptr); + if (dvi_ptr==dvi_limit) dvi_swap(); + } + +@p static void dvi_swap(void) /*outputs half of the buffer*/ +{@+if (dvi_limit==dvi_buf_size) + {@+write_dvi(0, half_buf-1);dvi_limit=half_buf; + dvi_offset=dvi_offset+dvi_buf_size;dvi_ptr=0; + } +else{@+write_dvi(half_buf, dvi_buf_size-1);dvi_limit=dvi_buf_size; + } +dvi_gone=dvi_gone+half_buf; +} + +@ Here is how we clean out the buffer when \TeX\ is all through; |dvi_ptr| +will be a multiple of~4. + +@<Empty the last bytes out of |dvi_buf|@>= +if (dvi_limit==half_buf) write_dvi(half_buf, dvi_buf_size-1); +if (dvi_ptr > 0) write_dvi(0, dvi_ptr-1) + +@ The |dvi_four| procedure outputs four bytes in two's complement notation, +without risking arithmetic overflow. + +@p static void dvi_four(int @!x) +{@+if (x >= 0) dvi_out(x/0100000000)@; +else{@+x=x+010000000000; + x=x+010000000000; + dvi_out((x/0100000000)+128); + } +x=x%0100000000;dvi_out(x/0200000); +x=x%0200000;dvi_out(x/0400); +dvi_out(x%0400); +} + +@ A mild optimization of the output is performed by the |dvi_pop| +routine, which issues a |pop| unless it is possible to cancel a +`|push| |pop|' pair. The parameter to |dvi_pop| is the byte address +following the old |push| that matches the new |pop|. + +@p static void dvi_pop(int @!l) +{@+if ((l==dvi_offset+dvi_ptr)&&(dvi_ptr > 0)) decr(dvi_ptr); +else dvi_out(pop); +} + +@ Here's a procedure that outputs a font definition. Since \TeX82 uses at +most 256 different fonts per job, |fnt_def1| is always used as the command code. + +@p static void dvi_font_def(internal_font_number @!f) +{@+int k; /*index into |str_pool|*/ +dvi_out(fnt_def1); +dvi_out(f-font_base-1);@/ +dvi_out(qo(font_check[f].b0)); +dvi_out(qo(font_check[f].b1)); +dvi_out(qo(font_check[f].b2)); +dvi_out(qo(font_check[f].b3));@/ +dvi_four(font_size[f]); +dvi_four(font_dsize[f]);@/ +dvi_out(length(font_area[f])); +dvi_out(length(font_name[f])); +@<Output the font name whose internal number is |f|@>; +} + +@ @<Output the font name whose internal number is |f|@>= +for (k=str_start[font_area[f]]; k<=str_start[font_area[f]+1]-1; k++) + dvi_out(so(str_pool[k])); +for (k=str_start[font_name[f]]; k<=str_start[font_name[f]+1]-1; k++) + dvi_out(so(str_pool[k])) + +@ Versions of \TeX\ intended for small computers might well choose to omit +the ideas in the next few parts of this program, since it is not really +necessary to optimize the \.{DVI} code by making use of the |w0|, |x0|, +|y0|, and |z0| commands. Furthermore, the algorithm that we are about to +describe does not pretend to give an optimum reduction in the length +of the \.{DVI} code; after all, speed is more important than compactness. +But the method is surprisingly effective, and it takes comparatively little +time. + +We can best understand the basic idea by first considering a simpler problem +that has the same essential characteristics. Given a sequence of digits, +say $3\,1\,4\,1\,5\,9\,2\,6\,5\,3\,5\,8\,9$, we want to assign subscripts +$d$, $y$, or $z$ to each digit so as to maximize the number of ``$y$-hits'' +and ``$z$-hits''; a $y$-hit is an instance of two appearances of the same +digit with the subscript $y$, where no $y$'s intervene between the two +appearances, and a $z$-hit is defined similarly. For example, the sequence +above could be decorated with subscripts as follows: +$$3_z\,1_y\,4_d\,1_y\,5_y\,9_d\,2_d\,6_d\,5_y\,3_z\,5_y\,8_d\,9_d.$$ +There are three $y$-hits ($1_y\ldots1_y$ and $5_y\ldots5_y\ldots5_y$) and +one $z$-hit ($3_z\ldots3_z$); there are no $d$-hits, since the two appearances +of $9_d$ have $d$'s between them, but we don't count $d$-hits so it doesn't +matter how many there are. These subscripts are analogous to the \.{DVI} +commands called \\{down}, $y$, and $z$, and the digits are analogous to +different amounts of vertical motion; a $y$-hit or $z$-hit corresponds to +the opportunity to use the one-byte commands |y0| or |z0| in a \.{DVI} file. + +\TeX's method of assigning subscripts works like this: Append a new digit, +say $\delta$, to the right of the sequence. Now look back through the +sequence until one of the following things happens: (a)~You see +$\delta_y$ or $\delta_z$, and this was the first time you encountered a +$y$ or $z$ subscript, respectively. Then assign $y$ or $z$ to the new +$\delta$; you have scored a hit. (b)~You see $\delta_d$, and no $y$ +subscripts have been encountered so far during this search. Then change +the previous $\delta_d$ to $\delta_y$ (this corresponds to changing a +command in the output buffer), and assign $y$ to the new $\delta$; it's +another hit. (c)~You see $\delta_d$, and a $y$ subscript has been seen +but not a $z$. Change the previous $\delta_d$ to $\delta_z$ and assign +$z$ to the new $\delta$. (d)~You encounter both $y$ and $z$ subscripts +before encountering a suitable $\delta$, or you scan all the way to the +front of the sequence. Assign $d$ to the new $\delta$; this assignment may +be changed later. + +The subscripts $3_z\,1_y\,4_d\ldots\,$ in the example above were, in fact, +produced by this procedure, as the reader can verify. (Go ahead and try it.) + +@ In order to implement such an idea, \TeX\ maintains a stack of pointers +to the \\{down}, $y$, and $z$ commands that have been generated for the +current page. And there is a similar stack for \\{right}, |w|, and |x| +commands. These stacks are called the down stack and right stack, and their +top elements are maintained in the variables |down_ptr| and |right_ptr|. + +Each entry in these stacks contains four fields: The |width| field is +the amount of motion down or to the right; the |location| field is the +byte number of the \.{DVI} command in question (including the appropriate +|dvi_offset|); the |link| field points to the next item below this one +on the stack; and the |info| field encodes the options for possible change +in the \.{DVI} command. + +@d movement_node_size 3 /*number of words per entry in the down and right stacks*/ +@d location(A) mem[A+2].i /*\.{DVI} byte number for a movement command*/ + +@<Glob...@>= +static pointer @!down_ptr, @!right_ptr; /*heads of the down and right stacks*/ + +@ @<Set init...@>= +down_ptr=null;right_ptr=null; + +@ Here is a subroutine that produces a \.{DVI} command for some specified +downward or rightward motion. It has two parameters: |w| is the amount +of motion, and |o| is either |down1| or |right1|. We use the fact that +the command codes have convenient arithmetic properties: |y1-down1==w1-right1| +and |z1-down1==x1-right1|. + +@p static void movement(scaled @!w, eight_bits @!o) +{@+ +small_number mstate; /*have we seen a |y| or |z|?*/ +pointer @!p, @!q; /*current and top nodes on the stack*/ +int @!k; /*index into |dvi_buf|, modulo |dvi_buf_size|*/ +q=get_node(movement_node_size); /*new node for the top of the stack*/ +width(q)=w;location(q)=dvi_offset+dvi_ptr; +if (o==down1) + {@+link(q)=down_ptr;down_ptr=q; + } +else{@+link(q)=right_ptr;right_ptr=q; + } +@<Look at the other stack entries until deciding what sort of \.{DVI} command to generate; +|goto found| if node |p| is a ``hit''@>; +@<Generate a |down| or |right| command for |w| and |return|@>; +found: @<Generate a |y0| or |z0| command in order to reuse a previous appearance of~|w|@>; +} + +@ The |info| fields in the entries of the down stack or the right stack +have six possible settings: |y_here| or |z_here| mean that the \.{DVI} +command refers to |y| or |z|, respectively (or to |w| or |x|, in the +case of horizontal motion); |yz_OK| means that the \.{DVI} command is +\\{down} (or \\{right}) but can be changed to either |y| or |z| (or +to either |w| or |x|); |y_OK| means that it is \\{down} and can be changed +to |y| but not |z|; |z_OK| is similar; and |d_fixed| means it must stay +\\{down}. + +The four settings |yz_OK|, |y_OK|, |z_OK|, |d_fixed| would not need to +be distinguished from each other if we were simply solving the +digit-subscripting problem mentioned above. But in \TeX's case there is +a complication because of the nested structure of |push| and |pop| +commands. Suppose we add parentheses to the digit-subscripting problem, +redefining hits so that $\delta_y\ldots \delta_y$ is a hit if all $y$'s between +the $\delta$'s are enclosed in properly nested parentheses, and if the +parenthesis level of the right-hand $\delta_y$ is deeper than or equal to +that of the left-hand one. Thus, `(' and `)' correspond to `|push|' +and `|pop|'. Now if we want to assign a subscript to the final 1 in the +sequence +$$2_y\,7_d\,1_d\,(\,8_z\,2_y\,8_z\,)\,1$$ +we cannot change the previous $1_d$ to $1_y$, since that would invalidate +the $2_y\ldots2_y$ hit. But we can change it to $1_z$, scoring a hit +since the intervening $8_z$'s are enclosed in parentheses. + +The program below removes movement nodes that are introduced after a |push|, +before it outputs the corresponding |pop|. + +@d y_here 1 /*|info| when the movement entry points to a |y| command*/ +@d z_here 2 /*|info| when the movement entry points to a |z| command*/ +@d yz_OK 3 /*|info| corresponding to an unconstrained \\{down} command*/ +@d y_OK 4 /*|info| corresponding to a \\{down} that can't become a |z|*/ +@d z_OK 5 /*|info| corresponding to a \\{down} that can't become a |y|*/ +@d d_fixed 6 /*|info| corresponding to a \\{down} that can't change*/ + +@ When the |movement| procedure gets to the label |found|, the value of +|info(p)| will be either |y_here| or |z_here|. If it is, say, |y_here|, +the procedure generates a |y0| command (or a |w0| command), and marks +all |info| fields between |q| and |p| so that |y| is not OK in that range. + +@<Generate a |y0| or |z0| command...@>= +info(q)=info(p); +if (info(q)==y_here) + {@+dvi_out(o+y0-down1); /*|y0| or |w0|*/ + while (link(q)!=p) + {@+q=link(q); + switch (info(q)) { + case yz_OK: info(q)=z_OK;@+break; + case y_OK: info(q)=d_fixed;@+break; + default:do_nothing; + } + } + } +else{@+dvi_out(o+z0-down1); /*|z0| or |x0|*/ + while (link(q)!=p) + {@+q=link(q); + switch (info(q)) { + case yz_OK: info(q)=y_OK;@+break; + case z_OK: info(q)=d_fixed;@+break; + default:do_nothing; + } + } + } + +@ @<Generate a |down| or |right|...@>= +info(q)=yz_OK; +if (abs(w) >= 040000000) + {@+dvi_out(o+3); /*|down4| or |right4|*/ + dvi_four(w);return; + } +if (abs(w) >= 0100000) + {@+dvi_out(o+2); /*|down3| or |right3|*/ + if (w < 0) w=w+0100000000; + dvi_out(w/0200000);w=w%0200000;goto label2; + } +if (abs(w) >= 0200) + {@+dvi_out(o+1); /*|down2| or |right2|*/ + if (w < 0) w=w+0200000; + goto label2; + } +dvi_out(o); /*|down1| or |right1|*/ +if (w < 0) w=w+0400; +goto label1; +label2: dvi_out(w/0400); +label1: dvi_out(w%0400);return + +@ As we search through the stack, we are in one of three states, +|y_seen|, |z_seen|, or |none_seen|, depending on whether we have +encountered |y_here| or |z_here| nodes. These states are encoded as +multiples of 6, so that they can be added to the |info| fields for quick +decision-making. +@^inner loop@> + +@d none_seen 0 /*no |y_here| or |z_here| nodes have been encountered yet*/ +@d y_seen 6 /*we have seen |y_here| but not |z_here|*/ +@d z_seen 12 /*we have seen |z_here| but not |y_here|*/ + +@<Look at the other stack entries until deciding...@>= +p=link(q);mstate=none_seen; +while (p!=null) + {@+if (width(p)==w) @<Consider a node with matching width; |goto found| if it's +a hit@>@; + else switch (mstate+info(p)) { + case none_seen+y_here: mstate=y_seen;@+break; + case none_seen+z_here: mstate=z_seen;@+break; + case y_seen+z_here: case z_seen+y_here: goto not_found; + default:do_nothing; + } + p=link(p); + } +not_found: + +@ We might find a valid hit in a |y| or |z| byte that is already gone +from the buffer. But we can't change bytes that are gone forever; ``the +moving finger writes, $\ldots\,\,$.'' + +@<Consider a node with matching width...@>= +switch (mstate+info(p)) { +case none_seen+yz_OK: case none_seen+y_OK: case z_seen+yz_OK: case z_seen+y_OK: @t@>@;@/ + if (location(p) < dvi_gone) goto not_found; + else@<Change buffered instruction to |y| or |w| and |goto found|@>@;@+break; +case none_seen+z_OK: case y_seen+yz_OK: case y_seen+z_OK: @t@>@;@/ + if (location(p) < dvi_gone) goto not_found; + else@<Change buffered instruction to |z| or |x| and |goto found|@>@;@+break; +case none_seen+y_here: case none_seen+z_here: case y_seen+z_here: case z_seen+y_here: goto found; +default:do_nothing; +} + +@ @<Change buffered instruction to |y| or |w| and |goto found|@>= +{@+k=location(p)-dvi_offset; +if (k < 0) k=k+dvi_buf_size; +dvi_buf[k]=dvi_buf[k]+y1-down1; +info(p)=y_here;goto found; +} + +@ @<Change buffered instruction to |z| or |x| and |goto found|@>= +{@+k=location(p)-dvi_offset; +if (k < 0) k=k+dvi_buf_size; +dvi_buf[k]=dvi_buf[k]+z1-down1; +info(p)=z_here;goto found; +} + +@ In case you are wondering when all the movement nodes are removed from +\TeX's memory, the answer is that they are recycled just before +|hlist_out| and |vlist_out| finish outputting a box. This restores the +down and right stacks to the state they were in before the box was output, +except that some |info|'s may have become more restrictive. + +@p static void prune_movements(int @!l) + /*delete movement nodes with |location >= l|*/ +{@+ +pointer p; /*node being deleted*/ +while (down_ptr!=null) + {@+if (location(down_ptr) < l) goto done; + p=down_ptr;down_ptr=link(p);free_node(p, movement_node_size); + } +done: while (right_ptr!=null) + {@+if (location(right_ptr) < l) return; + p=right_ptr;right_ptr=link(p);free_node(p, movement_node_size); + } +} + +@ The actual distances by which we want to move might be computed as the +sum of several separate movements. For example, there might be several +glue nodes in succession, or we might want to move right by the width of +some box plus some amount of glue. More importantly, the baselineskip +distances are computed in terms of glue together with the depth and +height of adjacent boxes, and we want the \.{DVI} file to lump these +three quantities together into a single motion. + +Therefore, \TeX\ maintains two pairs of global variables: |dvi_h| and |dvi_v| +are the |h| and |v| coordinates corresponding to the commands actually +output to the \.{DVI} file, while |cur_h| and |cur_v| are the coordinates +corresponding to the current state of the output routines. Coordinate +changes will accumulate in |cur_h| and |cur_v| without being reflected +in the output, until such a change becomes necessary or desirable; we +can call the |movement| procedure whenever we want to make |dvi_h==cur_h| +or |dvi_v==cur_v|. + +The current font reflected in the \.{DVI} output is called |dvi_f|; +there is no need for a `\\{cur\_f}' variable. + +The depth of nesting of |hlist_out| and |vlist_out| is called |cur_s|; +this is essentially the depth of |push| commands in the \.{DVI} output. + +@d synch_h if (cur_h!=dvi_h) + {@+movement(cur_h-dvi_h, right1);dvi_h=cur_h; + } +@d synch_v if (cur_v!=dvi_v) + {@+movement(cur_v-dvi_v, down1);dvi_v=cur_v; + } + +@<Glob...@>= +static scaled @!dvi_h, @!dvi_v; /*a \.{DVI} reader program thinks we are here*/ +static scaled @!cur_h, @!cur_v; /*\TeX\ thinks we are here*/ +static internal_font_number @!dvi_f; /*the current font*/ +static int @!cur_s; /*current depth of output box nesting, initially $-1$*/ + +@ @<Initialize variables as |ship_out| begins@>= +dvi_h=0;dvi_v=0;cur_h=h_offset;dvi_f=null_font; +ensure_dvi_open; +if (total_pages==0) + {@+dvi_out(pre);dvi_out(id_byte); /*output the preamble*/ +@^preamble of \.{DVI} file@> + dvi_four(25400000);dvi_four(473628672); /*conversion ratio for sp*/ + prepare_mag();dvi_four(mag); /*magnification factor is frozen*/ + old_setting=selector;selector=new_string; + print(" TeX output ");print_int(year);print_char('.'); + print_two(month);print_char('.');print_two(day); + print_char(':');print_two(time/60); + print_two(time%60); + selector=old_setting;dvi_out(cur_length); + for (s=str_start[str_ptr]; s<=pool_ptr-1; s++) dvi_out(so(str_pool[s])); + pool_ptr=str_start[str_ptr]; /*flush the current string*/ + } + +@ When |hlist_out| is called, its duty is to output the box represented +by the |hlist_node| pointed to by |temp_ptr|. The reference point of that +box has coordinates |(cur_h, cur_v)|. + +Similarly, when |vlist_out| is called, its duty is to output the box represented +by the |vlist_node| pointed to by |temp_ptr|. The reference point of that +box has coordinates |(cur_h, cur_v)|. +@^recursion@> + +@p static void vlist_out(void); /*|hlist_out| and |vlist_out| are mutually + recursive*/ + +@ The recursive procedures |hlist_out| and |vlist_out| each have local variables +|save_h| and |save_v| to hold the values of |dvi_h| and |dvi_v| just before +entering a new level of recursion. In effect, the values of |save_h| and +|save_v| on \TeX's run-time stack correspond to the values of |h| and |v| +that a \.{DVI}-reading program will push onto its coordinate stack. + +@p @t\4@>@<Declare procedures needed in |hlist_out|, |vlist_out|@>@t@>@/ +static void hlist_out(void) /*output an |hlist_node| box*/ +{@+ +scaled base_line; /*the baseline coordinate for this box*/ +scaled @!left_edge; /*the left coordinate for this box*/ +scaled @!save_h, @!save_v; /*what |dvi_h| and |dvi_v| should pop to*/ +pointer @!this_box; /*pointer to containing box*/ +glue_ord @!g_order; /*applicable order of infinity for glue*/ +int @!g_sign; /*selects type of glue*/ +pointer @!p; /*current position in the hlist*/ +int @!save_loc; /*\.{DVI} byte location upon entry*/ +pointer @!leader_box; /*the leader box being replicated*/ +scaled @!leader_wd; /*width of leader box being replicated*/ +scaled @!lx; /*extra space between leader boxes*/ +bool @!outer_doing_leaders; /*were we doing leaders?*/ +scaled @!edge; /*left edge of sub-box, or right edge of leader space*/ +double @!glue_temp; /*glue value before rounding*/ +double @!cur_glue; /*glue seen so far*/ +scaled @!cur_g; /*rounded equivalent of |cur_glue| times the glue ratio*/ +cur_g=0;cur_glue=float_constant(0); +this_box=temp_ptr;g_order=glue_order(this_box); +g_sign=glue_sign(this_box);p=list_ptr(this_box); +incr(cur_s); +if (cur_s > 0) dvi_out(push); +if (cur_s > max_push) max_push=cur_s; +save_loc=dvi_offset+dvi_ptr;base_line=cur_v;left_edge=cur_h; +while (p!=null) @<Output node |p| for |hlist_out| and move to the next node, maintaining +the condition |cur_v=base_line|@>; +prune_movements(save_loc); +if (cur_s > 0) dvi_pop(save_loc); +decr(cur_s); +} + +@ We ought to give special care to the efficiency of one part of |hlist_out|, +since it belongs to \TeX's inner loop. When a |char_node| is encountered, +we save a little time by processing several nodes in succession until +reaching a non-|char_node|. The program uses the fact that |set_char_0==0|. +@^inner loop@> + +@<Output node |p| for |hlist_out|...@>= +reswitch: if (is_char_node(p)) + {@+synch_h;synch_v; + @/do@+{f=font(p);c=character(p); + if (f!=dvi_f) @<Change font |dvi_f| to |f|@>; + if (c >= qi(128)) dvi_out(set1); + dvi_out(qo(c));@/ + cur_h=cur_h+char_width(f, char_info(f, c)); + p=link(p); + }@+ while (!(!is_char_node(p))); + dvi_h=cur_h; + } +else@<Output the non-|char_node| |p| for |hlist_out| and move to the next node@>@; + +@ @<Change font |dvi_f| to |f|@>= +{@+if (!font_used[f]) + {@+dvi_font_def(f);font_used[f]=true; + } +if (f <= 64+font_base) dvi_out(f-font_base-1+fnt_num_0)@; +else{@+dvi_out(fnt1);dvi_out(f-font_base-1); + } +dvi_f=f; +} + +@ @<Output the non-|char_node| |p| for |hlist_out|...@>= +{@+switch (type(p)) { +case hlist_node: case vlist_node: @<Output a box in an hlist@>@;@+break; +case rule_node: {@+rule_ht=height(p);rule_dp=depth(p);rule_wd=width(p); + goto fin_rule; + } +case whatsit_node: @<Output the whatsit node |p| in an hlist@>;@+break; +case glue_node: @<Move right or output leaders@>@; +case kern_node: case math_node: cur_h=cur_h+width(p);@+break; +case ligature_node: @<Make node |p| look like a |char_node| and |goto reswitch|@>@; +default:do_nothing; +} @/ +goto next_p; +fin_rule: @<Output a rule in an hlist@>; +move_past: cur_h=cur_h+rule_wd; +next_p: p=link(p); +} + +@ @<Output a box in an hlist@>= +if (list_ptr(p)==null) cur_h=cur_h+width(p); +else{@+save_h=dvi_h;save_v=dvi_v; + cur_v=base_line+shift_amount(p); /*shift the box down*/ + temp_ptr=p;edge=cur_h; + if (type(p)==vlist_node) vlist_out();@+else hlist_out(); + dvi_h=save_h;dvi_v=save_v; + cur_h=edge+width(p);cur_v=base_line; + } + +@ @<Output a rule in an hlist@>= +if (is_running(rule_ht)) rule_ht=height(this_box); +if (is_running(rule_dp)) rule_dp=depth(this_box); +rule_ht=rule_ht+rule_dp; /*this is the rule thickness*/ +if ((rule_ht > 0)&&(rule_wd > 0)) /*we don't output empty rules*/ + {@+synch_h;cur_v=base_line+rule_dp;synch_v; + dvi_out(set_rule);dvi_four(rule_ht);dvi_four(rule_wd); + cur_v=base_line;dvi_h=dvi_h+rule_wd; + } + +@ @d billion float_constant(1000000000) +@d vet_glue(A) glue_temp=A; + if (glue_temp > billion) + glue_temp=billion; + else if (glue_temp < -billion) + glue_temp=-billion + +@<Move right or output leaders@>= +{@+g=glue_ptr(p);rule_wd=width(g)-cur_g; +if (g_sign!=normal) + {@+if (g_sign==stretching) + {@+if (stretch_order(g)==g_order) + {@+cur_glue=cur_glue+stretch(g); + vet_glue(float(glue_set(this_box))*cur_glue); +@^real multiplication@> + cur_g=round(glue_temp); + } + } + else if (shrink_order(g)==g_order) + {@+cur_glue=cur_glue-shrink(g); + vet_glue(float(glue_set(this_box))*cur_glue); + cur_g=round(glue_temp); + } + } +rule_wd=rule_wd+cur_g; +if (subtype(p) >= a_leaders) + @<Output leaders in an hlist, |goto fin_rule| if a rule or to |next_p| if done@>; +goto move_past; +} + +@ @<Output leaders in an hlist...@>= +{@+leader_box=leader_ptr(p); +if (type(leader_box)==rule_node) + {@+rule_ht=height(leader_box);rule_dp=depth(leader_box); + goto fin_rule; + } +leader_wd=width(leader_box); +if ((leader_wd > 0)&&(rule_wd > 0)) + {@+rule_wd=rule_wd+10; /*compensate for floating-point rounding*/ + edge=cur_h+rule_wd;lx=0; + @<Let |cur_h| be the position of the first box, and set |leader_wd+lx| to the spacing +between corresponding parts of boxes@>; + while (cur_h+leader_wd <= edge) + @<Output a leader box at |cur_h|, then advance |cur_h| by |leader_wd+lx|@>; + cur_h=edge-10;goto next_p; + } +} + +@ The calculations related to leaders require a bit of care. First, in the +case of |a_leaders| (aligned leaders), we want to move |cur_h| to +|left_edge| plus the smallest multiple of |leader_wd| for which the result +is not less than the current value of |cur_h|; i.e., |cur_h| should become +$|left_edge|+|leader_wd|\times\lceil +(|cur_h|-|left_edge|)/|leader_wd|\rceil$. The program here should work in +all cases even though some implementations of \PASCAL\ give nonstandard +results for the |/| operation when |cur_h| is less than |left_edge|. + +In the case of |c_leaders| (centered leaders), we want to increase |cur_h| +by half of the excess space not occupied by the leaders; and in the +case of |x_leaders| (expanded leaders) we increase |cur_h| +by $1/(q+1)$ of this excess space, where $q$ is the number of times the +leader box will be replicated. Slight inaccuracies in the division might +accumulate; half of this rounding error is placed at each end of the leaders. + +@<Let |cur_h| be the position of the first box,...@>= +if (subtype(p)==a_leaders) + {@+save_h=cur_h; + cur_h=left_edge+leader_wd*((cur_h-left_edge)/leader_wd); + if (cur_h < save_h) cur_h=cur_h+leader_wd; + } +else{@+lq=rule_wd/leader_wd; /*the number of box copies*/ + lr=rule_wd%leader_wd; /*the remaining space*/ + if (subtype(p)==c_leaders) cur_h=cur_h+(lr/2); + else{@+lx=lr/(lq+1); + cur_h=cur_h+((lr-(lq-1)*lx)/2); + } + } + +@ The `\\{synch}' operations here are intended to decrease the number of +bytes needed to specify horizontal and vertical motion in the \.{DVI} output. + +@<Output a leader box at |cur_h|,...@>= +{@+cur_v=base_line+shift_amount(leader_box);synch_v;save_v=dvi_v;@/ +synch_h;save_h=dvi_h;temp_ptr=leader_box; +outer_doing_leaders=doing_leaders;doing_leaders=true; +if (type(leader_box)==vlist_node) vlist_out();@+else hlist_out(); +doing_leaders=outer_doing_leaders; +dvi_v=save_v;dvi_h=save_h;cur_v=base_line; +cur_h=save_h+leader_wd+lx; +} + +@ The |vlist_out| routine is similar to |hlist_out|, but a bit simpler. + +@p static void vlist_out(void) /*output a |vlist_node| box*/ +{@+ +scaled left_edge; /*the left coordinate for this box*/ +scaled @!top_edge; /*the top coordinate for this box*/ +scaled @!save_h, @!save_v; /*what |dvi_h| and |dvi_v| should pop to*/ +pointer @!this_box; /*pointer to containing box*/ +glue_ord @!g_order; /*applicable order of infinity for glue*/ +int @!g_sign; /*selects type of glue*/ +pointer @!p; /*current position in the vlist*/ +int @!save_loc; /*\.{DVI} byte location upon entry*/ +pointer @!leader_box; /*the leader box being replicated*/ +scaled @!leader_ht; /*height of leader box being replicated*/ +scaled @!lx; /*extra space between leader boxes*/ +bool @!outer_doing_leaders; /*were we doing leaders?*/ +scaled @!edge; /*bottom boundary of leader space*/ +double @!glue_temp; /*glue value before rounding*/ +double @!cur_glue; /*glue seen so far*/ +scaled @!cur_g; /*rounded equivalent of |cur_glue| times the glue ratio*/ +cur_g=0;cur_glue=float_constant(0); +this_box=temp_ptr;g_order=glue_order(this_box); +g_sign=glue_sign(this_box);p=list_ptr(this_box); +incr(cur_s); +if (cur_s > 0) dvi_out(push); +if (cur_s > max_push) max_push=cur_s; +save_loc=dvi_offset+dvi_ptr;left_edge=cur_h;cur_v=cur_v-height(this_box); +top_edge=cur_v; +while (p!=null) @<Output node |p| for |vlist_out| and move to the next node, maintaining +the condition |cur_h=left_edge|@>; +prune_movements(save_loc); +if (cur_s > 0) dvi_pop(save_loc); +decr(cur_s); +} + +@ @<Output node |p| for |vlist_out|...@>= +{@+if (is_char_node(p)) confusion("vlistout"); +@:this can't happen vlistout}{\quad vlistout@> +else@<Output the non-|char_node| |p| for |vlist_out|@>; +next_p: p=link(p); +} + +@ @<Output the non-|char_node| |p| for |vlist_out|@>= +{@+switch (type(p)) { +case hlist_node: case vlist_node: @<Output a box in a vlist@>@;@+break; +case rule_node: {@+rule_ht=height(p);rule_dp=depth(p);rule_wd=width(p); + goto fin_rule; + } +case whatsit_node: @<Output the whatsit node |p| in a vlist@>;@+break; +case glue_node: @<Move down or output leaders@>@; +case kern_node: cur_v=cur_v+width(p);@+break; +default:do_nothing; +} @/ +goto next_p; +fin_rule: @<Output a rule in a vlist, |goto next_p|@>; +move_past: cur_v=cur_v+rule_ht; +} + +@ The |synch_v| here allows the \.{DVI} output to use one-byte commands +for adjusting |v| in most cases, since the baselineskip distance will +usually be constant. + +@<Output a box in a vlist@>= +if (list_ptr(p)==null) cur_v=cur_v+height(p)+depth(p); +else{@+cur_v=cur_v+height(p);synch_v; + save_h=dvi_h;save_v=dvi_v; + cur_h=left_edge+shift_amount(p); /*shift the box right*/ + temp_ptr=p; + if (type(p)==vlist_node) vlist_out();@+else hlist_out(); + dvi_h=save_h;dvi_v=save_v; + cur_v=save_v+depth(p);cur_h=left_edge; + } + +@ @<Output a rule in a vlist...@>= +if (is_running(rule_wd)) rule_wd=width(this_box); +rule_ht=rule_ht+rule_dp; /*this is the rule thickness*/ +cur_v=cur_v+rule_ht; +if ((rule_ht > 0)&&(rule_wd > 0)) /*we don't output empty rules*/ + {@+synch_h;synch_v; + dvi_out(put_rule);dvi_four(rule_ht);dvi_four(rule_wd); + } +goto next_p + +@ @<Move down or output leaders@>= +{@+g=glue_ptr(p);rule_ht=width(g)-cur_g; +if (g_sign!=normal) + {@+if (g_sign==stretching) + {@+if (stretch_order(g)==g_order) + {@+cur_glue=cur_glue+stretch(g); + vet_glue(float(glue_set(this_box))*cur_glue); +@^real multiplication@> + cur_g=round(glue_temp); + } + } + else if (shrink_order(g)==g_order) + {@+cur_glue=cur_glue-shrink(g); + vet_glue(float(glue_set(this_box))*cur_glue); + cur_g=round(glue_temp); + } + } +rule_ht=rule_ht+cur_g; +if (subtype(p) >= a_leaders) + @<Output leaders in a vlist, |goto fin_rule| if a rule or to |next_p| if done@>; +goto move_past; +} + +@ @<Output leaders in a vlist...@>= +{@+leader_box=leader_ptr(p); +if (type(leader_box)==rule_node) + {@+rule_wd=width(leader_box);rule_dp=0; + goto fin_rule; + } +leader_ht=height(leader_box)+depth(leader_box); +if ((leader_ht > 0)&&(rule_ht > 0)) + {@+rule_ht=rule_ht+10; /*compensate for floating-point rounding*/ + edge=cur_v+rule_ht;lx=0; + @<Let |cur_v| be the position of the first box, and set |leader_ht+lx| to the spacing +between corresponding parts of boxes@>; + while (cur_v+leader_ht <= edge) + @<Output a leader box at |cur_v|, then advance |cur_v| by |leader_ht+lx|@>; + cur_v=edge-10;goto next_p; + } +} + +@ @<Let |cur_v| be the position of the first box,...@>= +if (subtype(p)==a_leaders) + {@+save_v=cur_v; + cur_v=top_edge+leader_ht*((cur_v-top_edge)/leader_ht); + if (cur_v < save_v) cur_v=cur_v+leader_ht; + } +else{@+lq=rule_ht/leader_ht; /*the number of box copies*/ + lr=rule_ht%leader_ht; /*the remaining space*/ + if (subtype(p)==c_leaders) cur_v=cur_v+(lr/2); + else{@+lx=lr/(lq+1); + cur_v=cur_v+((lr-(lq-1)*lx)/2); + } + } + +@ When we reach this part of the program, |cur_v| indicates the top of a +leader box, not its baseline. + +@<Output a leader box at |cur_v|,...@>= +{@+cur_h=left_edge+shift_amount(leader_box);synch_h;save_h=dvi_h;@/ +cur_v=cur_v+height(leader_box);synch_v;save_v=dvi_v; +temp_ptr=leader_box; +outer_doing_leaders=doing_leaders;doing_leaders=true; +if (type(leader_box)==vlist_node) vlist_out();@+else hlist_out(); +doing_leaders=outer_doing_leaders; +dvi_v=save_v;dvi_h=save_h;cur_h=left_edge; +cur_v=save_v-height(leader_box)+leader_ht+lx; +} + +@ The |hlist_out| and |vlist_out| procedures are now complete, so we are +ready for the |ship_out| routine that gets them started in the first place. + +@p void ship_out(pointer @!p) /*output the box |p|*/ +{@+ +execute_output(p); +flush_node_list(p); +} + +@ @<Flush the box from memory, showing statistics if requested@>= +#ifdef @!STAT +if (tracing_stats > 1) + {@+print_nl("Memory usage before: "); +@.Memory usage...@> + print_int(var_used);print_char('&'); + print_int(dyn_used);print_char(';'); + } +#endif +flush_node_list(p); +#ifdef @!STAT +if (tracing_stats > 1) + {@+print(" after: "); + print_int(var_used);print_char('&'); + print_int(dyn_used);print("; still untouched: "); + print_int(hi_mem_min-lo_mem_max-1);print_ln(); + } +#endif + +@ @<Ship box |p| out@>= +@<Update the values of |max_h| and |max_v|; but if the page is too large, |goto done|@>; +@<Initialize variables as |ship_out| begins@>; +page_loc=dvi_offset+dvi_ptr; +dvi_out(bop); +for (k=0; k<=9; k++) dvi_four(count(k)); +dvi_four(last_bop);last_bop=page_loc; +cur_v=height(p)+v_offset;temp_ptr=p; +if (type(p)==vlist_node) vlist_out();@+else hlist_out(); +dvi_out(eop);incr(total_pages);cur_s=-1; +done: + +@ Sometimes the user will generate a huge page because other error messages +are being ignored. Such pages are not output to the \.{dvi} file, since they +may confuse the printing software. + +@<Update the values of |max_h| and |max_v|; but if the page is too large...@>= +if ((height(p) > max_dimen)||@|(depth(p) > max_dimen)||@| + (height(p)+depth(p)+v_offset > max_dimen)||@| + (width(p)+h_offset > max_dimen)) + {@+print_err("Huge page cannot be shipped out"); +@.Huge page...@> + help2("The page just created is more than 18 feet tall or",@/ + "more than 18 feet wide, so I suspect something went wrong."); + error(); + if (tracing_output <= 0) + {@+begin_diagnostic(); + print_nl("The following box has been deleted:"); +@.The following...deleted@> + show_box(p); + end_diagnostic(true); + } + goto done; + } +if (height(p)+depth(p)+v_offset > max_v) max_v=height(p)+depth(p)+v_offset; +if (width(p)+h_offset > max_h) max_h=width(p)+h_offset + +@ At the end of the program, we must finish things off by writing the +post\-amble. If |total_pages==0|, the \.{DVI} file was never opened. +If |total_pages >= 65536|, the \.{DVI} file will lie. And if +|max_push >= 65536|, the user deserves whatever chaos might ensue. + +An integer variable |k| will be declared for use by this routine. + +@<Finish the \.{DVI} file@>= +while (cur_s > -1) + {@+if (cur_s > 0) dvi_out(pop)@; + else{@+dvi_out(eop);incr(total_pages); + } + decr(cur_s); + } +if (total_pages==0) print_nl("No pages of output."); +@.No pages of output@> +else{@+dvi_out(post); /*beginning of the postamble*/ + dvi_four(last_bop);last_bop=dvi_offset+dvi_ptr-5; /*|post| location*/ + dvi_four(25400000);dvi_four(473628672); /*conversion ratio for sp*/ + prepare_mag();dvi_four(mag); /*magnification factor*/ + dvi_four(max_v);dvi_four(max_h);@/ + dvi_out(max_push/256);dvi_out(max_push%256);@/ + dvi_out((total_pages/256)%256);dvi_out(total_pages%256);@/ + @<Output the font definitions for all fonts that were used@>; + dvi_out(post_post);dvi_four(last_bop);dvi_out(id_byte);@/ + k=4+((dvi_buf_size-dvi_ptr)%4); /*the number of 223's*/ + while (k > 0) + {@+dvi_out(223);decr(k); + } + @<Empty the last bytes out of |dvi_buf|@>; + print_nl("Output written on ");slow_print(output_file_name); +@.Output written on x@> + print(" (");print_int(total_pages);print(" page"); + if (total_pages!=1) print_char('s'); + print(", ");print_int(dvi_offset+dvi_ptr);print(" bytes)."); + b_close(&dvi_file); + } + +@ @<Output the font definitions...@>= +while (font_ptr > font_base) + {@+if (font_used[font_ptr]) dvi_font_def(font_ptr); + decr(font_ptr); + } + +@* Packaging. +We're essentially done with the parts of \TeX\ that are concerned with +the input (|get_next|) and the output (|ship_out|). So it's time to +get heavily into the remaining part, which does the real work of typesetting. + +After lists are constructed, \TeX\ wraps them up and puts them into boxes. +Two major subroutines are given the responsibility for this task: |hpack| +applies to horizontal lists (hlists) and |vpack| applies to vertical lists +(vlists). The main duty of |hpack| and |vpack| is to compute the dimensions +of the resulting boxes, and to adjust the glue if one of those dimensions +is pre-specified. The computed sizes normally enclose all of the material +inside the new box; but some items may stick out if negative glue is used, +if the box is overfull, or if a \.{\\vbox} includes other boxes that have +been shifted left. + +The subroutine call |hpack(p, w, m)| returns a pointer to an |hlist_node| +for a box containing the hlist that starts at |p|. Parameter |w| specifies +a width; and parameter |m| is either `|exactly|' or `|additional|'. Thus, +|hpack(p, w, exactly)| produces a box whose width is exactly |w|, while +|hpack(p, w, additional)| yields a box whose width is the natural width plus +|w|. It is convenient to define a macro called `|natural|' to cover the +most common case, so that we can say |hpack(p, natural)| to get a box that +has the natural width of list |p|. + +Similarly, |vpack(p, w, m)| returns a pointer to a |vlist_node| for a +box containing the vlist that starts at |p|. In this case |w| represents +a height instead of a width; the parameter |m| is interpreted as in |hpack|. + +@d exactly 0 /*a box dimension is pre-specified*/ +@d additional 1 /*a box dimension is increased from the natural one*/ +@d natural 0, 0, 0, additional /*shorthand for parameters to |hpack| and |vpack|*/ + +@ The parameters to |hpack| and |vpack| correspond to \TeX's primitives +like `\.{\\hbox} \.{to} \.{300pt}', `\.{\\hbox} \.{spread} \.{10pt}'; note +that `\.{\\hbox}' with no dimension following it is equivalent to +`\.{\\hbox} \.{spread} \.{0pt}'. The |scan_spec| subroutine scans such +constructions in the user's input, including the mandatory left brace that +follows them, and it puts the specification onto |save_stack| so that the +desired box can later be obtained by executing the following code: +$$\vbox{\halign{#\hfil\cr +|save_ptr=save_ptr-2;|\cr +|hpack(p, saved(1), saved(0)).|\cr}}$$ +Special care is necessary to ensure that the special |save_stack| codes +are placed just below the new group code, because scanning can change +|save_stack| when \.{\\csname} appears. + +@p static void scan_spec(group_code @!c, bool @!three_codes) + /*scans a box specification and left brace*/ +{@+ +int @!s; /*temporarily saved value*/ +int @!spec_code; +if (three_codes) s=saved(0); +if (scan_keyword("to")) spec_code=exactly; +@.to@> +else if (scan_keyword("spread")) spec_code=additional; +@.spread@> +else{@+spec_code=additional;cur_val=cur_hfactor=cur_vfactor=0; + goto found; + } +scan_normal_dimen; +found: if (three_codes) + {@+saved(0)=s;incr(save_ptr); + } +saved(0)=spec_code;saved(1)=cur_val; +saved_hfactor(1)=cur_hfactor; +saved_vfactor(1)=cur_vfactor; +save_ptr=save_ptr+2; +new_save_level(c);scan_left_brace(); +} + +@ To figure out the glue setting, |hpack| and |vpack| determine how much +stretchability and shrinkability are present, considering all four orders +of infinity. The highest order of infinity that has a nonzero coefficient +is then used as if no other orders were present. + +For example, suppose that the given list contains six glue nodes with +the respective stretchabilities 3pt, 8fill, 5fil, 6pt, $-3$fil, $-8$fill. +Then the total is essentially 2fil; and if a total additional space of 6pt +is to be achieved by stretching, the actual amounts of stretch will be +0pt, 0pt, 15pt, 0pt, $-9$pt, and 0pt, since only `fil' glue will be +considered. (The `fill' glue is therefore not really stretching infinitely +with respect to `fil'; nobody would actually want that to happen.) + +The arrays |total_stretch| and |total_shrink| are used to determine how much +glue of each kind is present. A global variable |last_badness| is used +to implement \.{\\badness}. + +@<Glob...@>= +scaled @!total_stretch0[filll-normal+1], *const @!total_stretch = @!total_stretch0-normal, @!total_shrink0[filll-normal+1], *const @!total_shrink = @!total_shrink0-normal; + /*glue found by |hpack| or |vpack|*/ +int @!last_badness; /*badness of the most recently packaged box*/ + +@ If the global variable |adjust_tail| is non-null, the |hpack| routine +also removes all occurrences of |ins_node|, |mark_node|, and |adjust_node| +items and appends the resulting material onto the list that ends at +location |adjust_tail|. + +@<Glob...@>= +pointer @!adjust_tail; /*tail of adjustment list*/ + +@ @<Set init...@>=adjust_tail=null;last_badness=0; + +@ Here now is |hpack|, which contains few if any surprises. + +@p extern pointer hpack(pointer p, scaled w, scaled hf, scaled vf, small_number m); + +@ @<Clear dimensions to zero@>= +d=0;x=0; +total_stretch[normal]=0;total_shrink[normal]=0; +total_stretch[fil]=0;total_shrink[fil]=0; +total_stretch[fill]=0;total_shrink[fill]=0; +total_stretch[filll]=0;total_shrink[filll]=0 + +@ @<Examine node |p| in the hlist, taking account of its effect...@>= +@^inner loop@> +{@+reswitch: while (is_char_node(p)) + @<Incorporate character dimensions into the dimensions of the hbox that will contain~it, +then move to the next node@>; +if (p!=null) + {@+switch (type(p)) { + case hlist_node: case vlist_node: case rule_node: case unset_node: case unset_set_node: case unset_pack_node: + @<Incorporate box dimensions into the dimensions of the hbox that will contain~it@>@;@+break; + case ins_node: case mark_node: case adjust_node: if (adjust_tail!=null) + @<Transfer node |p| to the adjustment list@>@;@+break; + case whatsit_node: @<Incorporate a whatsit node into an hbox@>;@+break; + case glue_node: @<Incorporate glue into the horizontal totals@>@;@+break; + case kern_node: case math_node: x=x+width(p);@+break; + case ligature_node: @<Make node |p| look like a |char_node| and |goto reswitch|@>@; + default:do_nothing; + } @/ + p=link(p); + } +} + + +@ @<Make node |p| look like a |char_node| and |goto reswitch|@>= +{@+mem[lig_trick]=mem[lig_char(p)];link(lig_trick)=link(p); +p=lig_trick;goto reswitch; +} + +@ The code here implicitly uses the fact that running dimensions are +indicated by |null_flag|, which will be ignored in the calculations +because it is a highly negative number. + +@<Incorporate box dimensions into the dimensions of the hbox...@>= +{@+x=x+width(p); +if (type(p) >= rule_node) s=0;@+else s=shift_amount(p); +if (height(p)-s > h) h=height(p)-s; +if (depth(p)+s > d) d=depth(p)+s; +} + +@ The following code is part of \TeX's inner loop; i.e., adding another +character of text to the user's input will cause each of these instructions +to be exercised one more time. +@^inner loop@> + +@<Incorporate character dimensions into the dimensions of the hbox...@>= +{@+f=font(p);i=char_info(f, character(p));hd=height_depth(i); +x=x+char_width(f, i);@/ +s=char_height(f, hd);@+if (s > h) h=s; +s=char_depth(f, hd);@+if (s > d) d=s; +p=link(p); +} + +@ Although node |q| is not necessarily the immediate predecessor of node |p|, +it always points to some node in the list preceding |p|. Thus, we can delete +nodes by moving |q| when necessary. The algorithm takes linear time, and the +extra computation does not intrude on the inner loop unless it is necessary +to make a deletion. +@^inner loop@> + +@<Transfer node |p| to the adjustment list@>= +{@+while (link(q)!=p) q=link(q); +if (type(p)==adjust_node) + {@+link(adjust_tail)=adjust_ptr(p); + while (link(adjust_tail)!=null) adjust_tail=link(adjust_tail); + p=link(p);free_node(link(q), small_node_size); + } +else{@+link(adjust_tail)=p;adjust_tail=p;p=link(p); + } +link(q)=p;p=q; +} + +@ @<Incorporate glue into the horizontal totals@>= +{@+g=glue_ptr(p);x=x+width(g);@/ +o=stretch_order(g);total_stretch[o]=total_stretch[o]+stretch(g); +o=shrink_order(g);total_shrink[o]=total_shrink[o]+shrink(g); +if (subtype(p) >= a_leaders) + {@+g=leader_ptr(p); + if (height(g) > h) h=height(g); + if (depth(g) > d) d=depth(g); + } +} + +@ When we get to the present part of the program, |x| is the natural width +of the box being packaged. + +@<Determine the value of |width(r)| and the appropriate glue setting...@>= +if (m==additional) w=x+w; +width(r)=w;x=w-x; /*now |x| is the excess to be made up*/ +if (x==0) + {@+glue_sign(r)=normal;glue_order(r)=normal; + set_glue_ratio_zero(glue_set(r)); + goto end; + } +else if (x > 0) @<Determine horizontal glue stretch setting, then |return| or \hbox{|goto +common_ending|}@>@; +else@<Determine horizontal glue shrink setting, then |return| or \hbox{|goto common_ending|}@>@; + +@ @<Determine horizontal glue stretch setting...@>= +{@+@<Determine the stretch order@>; +glue_order(r)=o;glue_sign(r)=stretching; +if (total_stretch[o]!=0) glue_set(r)=unfloat(x/(double)total_stretch[o]); +@^real division@> +else{@+glue_sign(r)=normal; + set_glue_ratio_zero(glue_set(r)); /*there's nothing to stretch*/ + } +if (o==normal) if (list_ptr(r)!=null) + @<Report an underfull hbox and |goto common_ending|, if this box is sufficiently +bad@>; +goto end; +} + +@ @<Determine the stretch order@>= +if (total_stretch[filll]!=0) o=filll; +else if (total_stretch[fill]!=0) o=fill; +else if (total_stretch[fil]!=0) o=fil; +else o=normal + +@ @<Report an underfull hbox and |goto common_ending|, if...@>= +{@+last_badness=badness(x, total_stretch[normal]); +if (last_badness > hbadness) + {@+print_ln(); + if (last_badness > 100) print_nl("Underfull");@+else print_nl("Loose"); + print(" \\hbox (badness ");print_int(last_badness); +@.Underfull \\hbox...@> +@.Loose \\hbox...@> + goto common_ending; + } +} + +@ In order to provide a decent indication of where an overfull or underfull +box originated, we use a global variable |pack_begin_line| that is +set nonzero only when |hpack| is being called by the paragraph builder +or the alignment finishing routine. + +@<Glob...@>= +int @!pack_begin_line; /*source file line where the current paragraph + or alignment began; a negative value denotes alignment*/ + +@ @<Set init...@>= +pack_begin_line=0; + +@ @<Finish issuing a diagnostic message for an overfull or underfull hbox@>= +if (output_active) print(") has occurred while \\output is active"); +else{@+if (pack_begin_line!=0) + {@+if (pack_begin_line > 0) print(") in paragraph at lines "); + else print(") in alignment at lines "); + print_int(abs(pack_begin_line)); + print("--"); + } + else print(") detected at line "); + print_int(line); + } +print_ln();@/ +font_in_short_display=null_font;short_display(list_ptr(r));print_ln();@/ +begin_diagnostic();show_box(r);end_diagnostic(true) + +@ @<Determine horizontal glue shrink setting...@>= +{@+@<Determine the shrink order@>; +glue_order(r)=o;glue_sign(r)=shrinking; +if (total_shrink[o]!=0) glue_set(r)=unfloat((-x)/(double)total_shrink[o]); +@^real division@> +else{@+glue_sign(r)=normal; + set_glue_ratio_zero(glue_set(r)); /*there's nothing to shrink*/ + } +if ((total_shrink[o] < -x)&&(o==normal)&&(list_ptr(r)!=null)) + {@+last_badness=1000000; + set_glue_ratio_one(glue_set(r)); /*use the maximum shrinkage*/ + @<Report an overfull hbox and |goto common_ending|, if this box is sufficiently +bad@>; + } +else if (o==normal) if (list_ptr(r)!=null) + @<Report a tight hbox and |goto common_ending|, if this box is sufficiently bad@>; +goto end; +} + +@ @<Determine the shrink order@>= +if (total_shrink[filll]!=0) o=filll; +else if (total_shrink[fill]!=0) o=fill; +else if (total_shrink[fil]!=0) o=fil; +else o=normal + +@ @<Report an overfull hbox and |goto common_ending|, if...@>= +if ((-x-total_shrink[normal] > hfuzz)||(hbadness < 100)) + {@+if ((overfull_rule > 0)&&(-x-total_shrink[normal] > hfuzz)) + {@+while (link(q)!=null) q=link(q); + link(q)=new_rule(); + width(link(q))=overfull_rule; + } + print_ln();print_nl("Overfull \\hbox ("); +@.Overfull \\hbox...@> + print_scaled(-x-total_shrink[normal]);print("pt too wide"); + goto common_ending; + } + +@ @<Report a tight hbox and |goto common_ending|, if...@>= +{@+last_badness=badness(-x, total_shrink[normal]); +if (last_badness > hbadness) + {@+print_ln();print_nl("Tight \\hbox (badness ");print_int(last_badness); +@.Tight \\hbox...@> + goto common_ending; + } +} + +@ The |vpack| subroutine is actually a special case of a slightly more +general routine called |vpackage|, which has four parameters. The fourth +parameter, which is |max_dimen| in the case of |vpack|, specifies the +maximum depth of the page box that is constructed. The depth is first +computed by the normal rules; if it exceeds this limit, the reference +point is simply moved down until the limiting depth is attained. + + +@p +#define vpack(...) @[vpackage(__VA_ARGS__, max_dimen)@] /*special case of unconstrained depth*/ +extern pointer vpackage(pointer p, scaled h, scaled hf, scaled vf, small_number m, scaled l); + +@ @<Examine node |p| in the vlist, taking account of its effect...@>= +{@+if (is_char_node(p)) confusion("vpack"); +@:this can't happen vpack}{\quad vpack@> +else switch (type(p)) { + case hlist_node: case vlist_node: case rule_node: case unset_node: case unset_set_node: case unset_pack_node: + @<Incorporate box dimensions into the dimensions of the vbox that will contain~it@>@;@+break; + case whatsit_node: @<Incorporate a whatsit node into a vbox@>;@+break; + case glue_node: @<Incorporate glue into the vertical totals@>@;@+break; + case kern_node: {@+x=x+d+width(p);d=0; + } @+break; + default:do_nothing; + } +p=link(p); +} + +@ @<Incorporate box dimensions into the dimensions of the vbox...@>= +{@+x=x+d+height(p);d=depth(p); +if (type(p) >= rule_node) s=0;@+else s=shift_amount(p); +if (width(p)+s > w) w=width(p)+s; +} + +@ @<Incorporate glue into the vertical totals@>= +{@+x=x+d;d=0;@/ +g=glue_ptr(p);x=x+width(g);@/ +o=stretch_order(g);total_stretch[o]=total_stretch[o]+stretch(g); +o=shrink_order(g);total_shrink[o]=total_shrink[o]+shrink(g); +if (subtype(p) >= a_leaders) + {@+g=leader_ptr(p); + if (width(g) > w) w=width(g); + } +} + +@ When we get to the present part of the program, |x| is the natural height +of the box being packaged. + +@<Determine the value of |height(r)| and the appropriate glue setting...@>= +if (m==additional) h=x+h; +height(r)=h;x=h-x; /*now |x| is the excess to be made up*/ +if (x==0) + {@+glue_sign(r)=normal;glue_order(r)=normal; + set_glue_ratio_zero(glue_set(r)); + goto end; + } +else if (x > 0) @<Determine vertical glue stretch setting, then |return| or \hbox{|goto +common_ending|}@>@; +else@<Determine vertical glue shrink setting, then |return| or \hbox{|goto common_ending|}@>@; + +@ @<Determine vertical glue stretch setting...@>= +{@+@<Determine the stretch order@>; +glue_order(r)=o;glue_sign(r)=stretching; +if (total_stretch[o]!=0) glue_set(r)=unfloat(x/(double)total_stretch[o]); +@^real division@> +else{@+glue_sign(r)=normal; + set_glue_ratio_zero(glue_set(r)); /*there's nothing to stretch*/ + } +if (o==normal) if (list_ptr(r)!=null) + @<Report an underfull vbox and |goto common_ending|, if this box is sufficiently +bad@>; +goto end; +} + +@ @<Report an underfull vbox and |goto common_ending|, if...@>= +{@+last_badness=badness(x, total_stretch[normal]); +if (last_badness > vbadness) + {@+print_ln(); + if (last_badness > 100) print_nl("Underfull");@+else print_nl("Loose"); + print(" \\vbox (badness ");print_int(last_badness); +@.Underfull \\vbox...@> +@.Loose \\vbox...@> + goto common_ending; + } +} + +@ @<Finish issuing a diagnostic message for an overfull or underfull vbox@>= +if (output_active) print(") has occurred while \\output is active"); +else{@+if (pack_begin_line!=0) /*it's actually negative*/ + {@+print(") in alignment at lines "); + print_int(abs(pack_begin_line)); + print("--"); + } + else print(") detected at line "); + print_int(line); + print_ln();@/ + } +begin_diagnostic();show_box(r);end_diagnostic(true) + +@ @<Determine vertical glue shrink setting...@>= +{@+@<Determine the shrink order@>; +glue_order(r)=o;glue_sign(r)=shrinking; +if (total_shrink[o]!=0) glue_set(r)=unfloat((-x)/(double)total_shrink[o]); +@^real division@> +else{@+glue_sign(r)=normal; + set_glue_ratio_zero(glue_set(r)); /*there's nothing to shrink*/ + } +if ((total_shrink[o] < -x)&&(o==normal)&&(list_ptr(r)!=null)) + {@+last_badness=1000000; + set_glue_ratio_one(glue_set(r)); /*use the maximum shrinkage*/ + @<Report an overfull vbox and |goto common_ending|, if this box is sufficiently +bad@>; + } +else if (o==normal) if (list_ptr(r)!=null) + @<Report a tight vbox and |goto common_ending|, if this box is sufficiently bad@>; +goto end; +} + +@ @<Report an overfull vbox and |goto common_ending|, if...@>= +if ((-x-total_shrink[normal] > vfuzz)||(vbadness < 100)) + {@+print_ln();print_nl("Overfull \\vbox ("); +@.Overfull \\vbox...@> + print_scaled(-x-total_shrink[normal]);print("pt too high"); + goto common_ending; + } + +@ @<Report a tight vbox and |goto common_ending|, if...@>= +{@+last_badness=badness(-x, total_shrink[normal]); +if (last_badness > vbadness) + {@+print_ln();print_nl("Tight \\vbox (badness ");print_int(last_badness); +@.Tight \\vbox...@> + goto common_ending; + } +} + +@ When a box is being appended to the current vertical list, the +baselineskip calculation is handled by the |append_to_vlist| routine. + +@p void append_to_vlist(pointer @!b)@t\2\2@>@/ +{ bool height_known;@t\1@>@/ + height_known=(type(b)==hlist_node || type(b)==vlist_node ||@| + (type(b)==whatsit_node && subtype(b)==hset_node) ||@| + (type(b)==whatsit_node && subtype(b)==image_node));@/ + if (prev_depth > ignore_depth && height_known)@/ + {@+scaled d;@t\1@> /*deficiency of space between baselines*/ + pointer @!p; /*a new glue node*/ + {@+d=width(baseline_skip)-prev_depth-height(b); + if (d < line_skip_limit) p=new_param_glue(line_skip_code); + else{@+p=new_skip_param(baseline_skip_code); + width(temp_ptr)=d; /*|temp_ptr==glue_ptr(p)|*/ + } + link(tail)=p;tail=p; + }@+ +} @+ else @+if (prev_depth<=unknown_depth || prev_depth>ignore_depth )@t\2@>@/ + {@+pointer p; + p=new_baseline_node(baseline_skip, line_skip, line_skip_limit); + link(tail)= p;tail= p; + } + link(tail)=b;tail=b; + if (height_known) + prev_depth=depth(b); /* then also depth is known */ + else + prev_depth=unknown_depth; +} + +@* Data structures for math mode. +When \TeX\ reads a formula that is enclosed between \.\$'s, it constructs an +{\sl mlist}, which is essentially a tree structure representing that +formula. An mlist is a linear sequence of items, but we can regard it as +a tree structure because mlists can appear within mlists. For example, many +of the entries can be subscripted or superscripted, and such ``scripts'' +are mlists in their own right. + +An entire formula is parsed into such a tree before any of the actual +typesetting is done, because the current style of type is usually not +known until the formula has been fully scanned. For example, when the +formula `\.{\$a+b \\over c+d\$}' is being read, there is no way to tell +that `\.{a+b}' will be in script size until `\.{\\over}' has appeared. + +During the scanning process, each element of the mlist being built is +classified as a relation, a binary operator, an open parenthesis, etc., +or as a construct like `\.{\\sqrt}' that must be built up. This classification +appears in the mlist data structure. + +After a formula has been fully scanned, the mlist is converted to an hlist +so that it can be incorporated into the surrounding text. This conversion is +controlled by a recursive procedure that decides all of the appropriate +styles by a ``top-down'' process starting at the outermost level and working +in towards the subformulas. The formula is ultimately pasted together using +combinations of horizontal and vertical boxes, with glue and penalty nodes +inserted as necessary. + +An mlist is represented internally as a linked list consisting chiefly +of ``noads'' (pronounced ``no-adds''), to distinguish them from the somewhat +similar ``nodes'' in hlists and vlists. Certain kinds of ordinary nodes are +allowed to appear in mlists together with the noads; \TeX\ tells the difference +by means of the |type| field, since a noad's |type| is always greater than +that of a node. An mlist does not contain character nodes, hlist nodes, vlist +nodes, math nodes, ligature nodes, +or unset nodes; in particular, each mlist item appears in the +variable-size part of |mem|, so the |type| field is always present. + +@ Each noad is four or more words long. The first word contains the |type| +and |subtype| and |link| fields that are already so familiar to us; the +second, third, and fourth words are called the noad's |nucleus|, |subscr|, +and |supscr| fields. + +Consider, for example, the simple formula `\.{\$x\^2\$}', which would be +parsed into an mlist containing a single element called an |ord_noad|. +The |nucleus| of this noad is a representation of `\.x', the |subscr| is +empty, and the |supscr| is a representation of `\.2'. + +The |nucleus|, |subscr|, and |supscr| fields are further broken into +subfields. If |p| points to a noad, and if |q| is one of its principal +fields (e.g., |q==subscr(p)|), there are several possibilities for the +subfields, depending on the |math_type| of |q|. + +\yskip\hang|math_type(q)==math_char| means that |fam(q)| refers to one of +the sixteen font families, and |character(q)| is the number of a character +within a font of that family, as in a character node. + +\yskip\hang|math_type(q)==math_text_char| is similar, but the character is +unsubscripted and unsuperscripted and it is followed immediately by another +character from the same font. (This |math_type| setting appears only +briefly during the processing; it is used to suppress unwanted italic +corrections.) + +\yskip\hang|math_type(q)==empty| indicates a field with no value (the +corresponding attribute of noad |p| is not present). + +\yskip\hang|math_type(q)==sub_box| means that |info(q)| points to a box +node (either an |hlist_node| or a |vlist_node|) that should be used as the +value of the field. The |shift_amount| in the subsidiary box node is the +amount by which that box will be shifted downward. + +\yskip\hang|math_type(q)==sub_mlist| means that |info(q)| points to +an mlist; the mlist must be converted to an hlist in order to obtain +the value of this field. + +\yskip\noindent In the latter case, we might have |info(q)==null|. This +is not the same as |math_type(q)==empty|; for example, `\.{\$P\_\{\}\$}' +and `\.{\$P\$}' produce different results (the former will not have the +``italic correction'' added to the width of |P|, but the ``script skip'' +will be added). + +The definitions of subfields given here are evidently wasteful of space, +since a halfword is being used for the |math_type| although only three +bits would be needed. However, there are hardly ever many noads present at +once, since they are soon converted to nodes that take up even more space, +so we can afford to represent them in whatever way simplifies the +programming. + +@d noad_size 4 /*number of words in a normal noad*/ +@d nucleus(A) A+1 /*the |nucleus| field of a noad*/ +@d supscr(A) A+2 /*the |supscr| field of a noad*/ +@d subscr(A) A+3 /*the |subscr| field of a noad*/ +@d math_type(A) link(A) /*a |halfword| in |mem|*/ +@d fam font /*a |quarterword| in |mem|*/ +@d math_char 1 /*|math_type| when the attribute is simple*/ +@d sub_box 2 /*|math_type| when the attribute is a box*/ +@d sub_mlist 3 /*|math_type| when the attribute is a formula*/ +@d math_text_char 4 /*|math_type| when italic correction is dubious*/ + +@ Each portion of a formula is classified as Ord, Op, Bin, Rel, Ope, +Clo, Pun, or Inn, for purposes of spacing and line breaking. An +|ord_noad|, |op_noad|, |bin_noad|, |rel_noad|, |open_noad|, |close_noad|, +|punct_noad|, or |inner_noad| is used to represent portions of the various +types. For example, an `\.=' sign in a formula leads to the creation of a +|rel_noad| whose |nucleus| field is a representation of an equals sign +(usually |fam==0|, |character==075|). A formula preceded by \.{\\mathrel} +also results in a |rel_noad|. When a |rel_noad| is followed by an +|op_noad|, say, and possibly separated by one or more ordinary nodes (not +noads), \TeX\ will insert a penalty node (with the current |rel_penalty|) +just after the formula that corresponds to the |rel_noad|, unless there +already was a penalty immediately following; and a ``thick space'' will be +inserted just before the formula that corresponds to the |op_noad|. + +A noad of type |ord_noad|, |op_noad|, \dots, |inner_noad| usually +has a |subtype==normal|. The only exception is that an |op_noad| might +have |subtype==limits| or |no_limits|, if the normal positioning of +limits has been overridden for this operator. + +@d ord_noad (unset_node+3) /*|type| of a noad classified Ord*/ +@d op_noad (ord_noad+1) /*|type| of a noad classified Op*/ +@d bin_noad (ord_noad+2) /*|type| of a noad classified Bin*/ +@d rel_noad (ord_noad+3) /*|type| of a noad classified Rel*/ +@d open_noad (ord_noad+4) /*|type| of a noad classified Ope*/ +@d close_noad (ord_noad+5) /*|type| of a noad classified Clo*/ +@d punct_noad (ord_noad+6) /*|type| of a noad classified Pun*/ +@d inner_noad (ord_noad+7) /*|type| of a noad classified Inn*/ +@d limits 1 /*|subtype| of |op_noad| whose scripts are to be above, below*/ +@d no_limits 2 /*|subtype| of |op_noad| whose scripts are to be normal*/ + +@ A |radical_noad| is five words long; the fifth word is the |left_delimiter| +field, which usually represents a square root sign. + +A |fraction_noad| is six words long; it has a |right_delimiter| field +as well as a |left_delimiter|. + +Delimiter fields are of type |four_quarters|, and they have four subfields +called |small_fam|, |small_char|, |large_fam|, |large_char|. These subfields +represent variable-size delimiters by giving the ``small'' and ``large'' +starting characters, as explained in Chapter~17 of {\sl The \TeX book}. +@:TeXbook}{\sl The \TeX book@> + +A |fraction_noad| is actually quite different from all other noads. Not +only does it have six words, it has |thickness|, |denominator|, and +|numerator| fields instead of |nucleus|, |subscr|, and |supscr|. The +|thickness| is a scaled value that tells how thick to make a fraction +rule; however, the special value |default_code| is used to stand for the +|default_rule_thickness| of the current size. The |numerator| and +|denominator| point to mlists that define a fraction; we always have +$$\hbox{|math_type(numerator)==math_type(denominator)==sub_mlist|}.$$ The +|left_delimiter| and |right_delimiter| fields specify delimiters that will +be placed at the left and right of the fraction. In this way, a +|fraction_noad| is able to represent all of \TeX's operators \.{\\over}, +\.{\\atop}, \.{\\above}, \.{\\overwithdelims}, \.{\\atopwithdelims}, and + \.{\\abovewithdelims}. + +@d left_delimiter(A) A+4 /*first delimiter field of a noad*/ +@d right_delimiter(A) A+5 /*second delimiter field of a fraction noad*/ +@d radical_noad (inner_noad+1) /*|type| of a noad for square roots*/ +@d radical_noad_size 5 /*number of |mem| words in a radical noad*/ +@d fraction_noad (radical_noad+1) /*|type| of a noad for generalized fractions*/ +@d fraction_noad_size 6 /*number of |mem| words in a fraction noad*/ +@d small_fam(A) mem[A].qqqq.b0 /*|fam| for ``small'' delimiter*/ +@d small_char(A) mem[A].qqqq.b1 /*|character| for ``small'' delimiter*/ +@d large_fam(A) mem[A].qqqq.b2 /*|fam| for ``large'' delimiter*/ +@d large_char(A) mem[A].qqqq.b3 /*|character| for ``large'' delimiter*/ +@d thickness(A) width(A) /*|thickness| field in a fraction noad*/ +@d default_code 010000000000 /*denotes |default_rule_thickness|*/ +@d numerator(A) supscr(A) /*|numerator| field in a fraction noad*/ +@d denominator(A) subscr(A) /*|denominator| field in a fraction noad*/ + +@ The global variable |empty_field| is set up for initialization of empty +fields in new noads. Similarly, |null_delimiter| is for the initialization +of delimiter fields. + +@<Glob...@>= +static two_halves @!empty_field; +static four_quarters @!null_delimiter; + +@ @<Set init...@>= +empty_field.rh=empty;empty_field.lh=null;@/ +null_delimiter.b0=0;null_delimiter.b1=min_quarterword;@/ +null_delimiter.b2=0;null_delimiter.b3=min_quarterword; + +@ The |new_noad| function creates an |ord_noad| that is completely null. + +@p static pointer new_noad(void) +{@+pointer p; +p=get_node(noad_size); +type(p)=ord_noad;subtype(p)=normal; +mem[nucleus(p)].hh=empty_field; +mem[subscr(p)].hh=empty_field; +mem[supscr(p)].hh=empty_field; +return p; +} + +@ A few more kinds of noads will complete the set: An |under_noad| has its +nucleus underlined; an |over_noad| has it overlined. An |accent_noad| places +an accent over its nucleus; the accent character appears as +|fam(accent_chr(p))| and |character(accent_chr(p))|. A |vcenter_noad| +centers its nucleus vertically with respect to the axis of the formula; +in such noads we always have |math_type(nucleus(p))==sub_box|. + +And finally, we have |left_noad| and |right_noad| types, to implement +\TeX's \.{\\left} and \.{\\right} as well as \eTeX's \.{\\middle}. +The |nucleus| of such noads is +replaced by a |delimiter| field; thus, for example, `\.{\\left(}' produces +a |left_noad| such that |delimiter(p)| holds the family and character +codes for all left parentheses. A |left_noad| never appears in an mlist +except as the first element, and a |right_noad| never appears in an mlist +except as the last element; furthermore, we either have both a |left_noad| +and a |right_noad|, or neither one is present. The |subscr| and |supscr| +fields are always |empty| in a |left_noad| and a |right_noad|. + +@d under_noad (fraction_noad+1) /*|type| of a noad for underlining*/ +@d over_noad (under_noad+1) /*|type| of a noad for overlining*/ +@d accent_noad (over_noad+1) /*|type| of a noad for accented subformulas*/ +@d accent_noad_size 5 /*number of |mem| words in an accent noad*/ +@d accent_chr(A) A+4 /*the |accent_chr| field of an accent noad*/ +@d vcenter_noad (accent_noad+1) /*|type| of a noad for \.{\\vcenter}*/ +@d left_noad (vcenter_noad+1) /*|type| of a noad for \.{\\left}*/ +@d right_noad (left_noad+1) /*|type| of a noad for \.{\\right}*/ +@d delimiter(A) nucleus(A) /*|delimiter| field in left and right noads*/ +@d middle_noad 1 /*|subtype| of right noad representing \.{\\middle}*/ +@d scripts_allowed(A) (type(A) >= ord_noad)&&(type(A) < left_noad) + +@ Math formulas can also contain instructions like \.{\\textstyle} that +override \TeX's normal style rules. A |style_node| is inserted into the +data structure to record such instructions; it is three words long, so it +is considered a node instead of a noad. The |subtype| is either |display_style| +or |text_style| or |script_style| or |script_script_style|. The +second and third words of a |style_node| are not used, but they are +present because a |choice_node| is converted to a |style_node|. + +\TeX\ uses even numbers 0, 2, 4, 6 to encode the basic styles +|display_style|, \dots, |script_script_style|, and adds~1 to get the +``cramped'' versions of these styles. This gives a numerical order that +is backwards from the convention of Appendix~G in {\sl The \TeX book\/}; +i.e., a smaller style has a larger numerical value. +@:TeXbook}{\sl The \TeX book@> + +@d style_node (unset_node+1) /*|type| of a style node*/ +@d style_node_size 3 /*number of words in a style node*/ +@d display_style 0 /*|subtype| for \.{\\displaystyle}*/ +@d text_style 2 /*|subtype| for \.{\\textstyle}*/ +@d script_style 4 /*|subtype| for \.{\\scriptstyle}*/ +@d script_script_style 6 /*|subtype| for \.{\\scriptscriptstyle}*/ +@d cramped 1 /*add this to an uncramped style if you want to cramp it*/ + +@p static pointer new_style(small_number @!s) /*create a style node*/ +{@+pointer p; /*the new node*/ +p=get_node(style_node_size);type(p)=style_node; +subtype(p)=s;width(p)=0;depth(p)=0; /*the |width| and |depth| are not used*/ +return p; +} + +@ Finally, the \.{\\mathchoice} primitive creates a |choice_node|, which +has special subfields |display_mlist|, |text_mlist|, |script_mlist|, +and |script_script_mlist| pointing to the mlists for each style. + +@d choice_node (unset_node+2) /*|type| of a choice node*/ +@d display_mlist(A) info(A+1) /*mlist to be used in display style*/ +@d text_mlist(A) link(A+1) /*mlist to be used in text style*/ +@d script_mlist(A) info(A+2) /*mlist to be used in script style*/ +@d script_script_mlist(A) link(A+2) /*mlist to be used in scriptscript style*/ + +@p static pointer new_choice(void) /*create a choice node*/ +{@+pointer p; /*the new node*/ +p=get_node(style_node_size);type(p)=choice_node; +subtype(p)=0; /*the |subtype| is not used*/ +display_mlist(p)=null;text_mlist(p)=null;script_mlist(p)=null; +script_script_mlist(p)=null; +return p; +} + +@ Let's consider now the previously unwritten part of |show_node_list| +that displays the things that can only be present in mlists; this +program illustrates how to access the data structures just defined. + +In the context of the following program, |p| points to a node or noad that +should be displayed, and the current string contains the ``recursion history'' +that leads to this point. The recursion history consists of a dot for each +outer level in which |p| is subsidiary to some node, or in which |p| is +subsidiary to the |nucleus| field of some noad; the dot is replaced by +`\.\_' or `\.\^' or `\./' or `\.\\' if |p| is descended from the |subscr| +or |supscr| or |denominator| or |numerator| fields of noads. For example, +the current string would be `\.{.\^.\_/}' if |p| points to the |ord_noad| for +|x| in the (ridiculous) formula +`\.{\$\\sqrt\{a\^\{\\mathinner\{b\_\{c\\over x+y\}\}\}\}\$}'. + +@<Cases of |show_node_list| that arise...@>= +case style_node: print_style(subtype(p));@+break; +case choice_node: @<Display choice node |p|@>@;@+break; +case ord_noad: case op_noad: case bin_noad: case rel_noad: case open_noad: case close_noad: case punct_noad: case inner_noad: + case radical_noad: case over_noad: case under_noad: case vcenter_noad: case accent_noad: + case left_noad: case right_noad: @<Display normal noad |p|@>@;@+break; +case fraction_noad: @<Display fraction noad |p|@>@;@+break; + +@ Here are some simple routines used in the display of noads. + +@<Declare procedures needed for displaying the elements of mlists@>= +static void print_fam_and_char(pointer @!p) /*prints family and character*/ +{@+print_esc("fam");print_int(fam(p));print_char(' '); +print_ASCII(qo(character(p))); +} +@# +static void print_delimiter(pointer @!p) /*prints a delimiter as 24-bit hex value*/ +{@+int a; /*accumulator*/ +a=small_fam(p)*256+qo(small_char(p)); +a=a*0x1000+large_fam(p)*256+qo(large_char(p)); +if (a < 0) print_int(a); /*this should never happen*/ +else print_hex(a); +} + +@ The next subroutine will descend to another level of recursion when a +subsidiary mlist needs to be displayed. The parameter |c| indicates what +character is to become part of the recursion history. An empty mlist is +distinguished from a field with |math_type(p)==empty|, because these are +not equivalent (as explained above). +@^recursion@> + +@<Declare procedures needed for displaying...@>= +static void show_info(void); /*|show_node_list(info(temp_ptr))|*/ +static void print_subsidiary_data(pointer @!p, ASCII_code @!c) + /*display a noad field*/ +{@+if (cur_length >= depth_threshold) + {@+if (math_type(p)!=empty) print(" []"); + } +else{@+append_char(c); /*include |c| in the recursion history*/ + temp_ptr=p; /*prepare for |show_info| if recursion is needed*/ + switch (math_type(p)) { + case math_char: {@+print_ln();print_current_string();print_fam_and_char(p); + } @+break; + case sub_box: show_info();@+break; /*recursive call*/ + case sub_mlist: if (info(p)==null) + {@+print_ln();print_current_string();print("{}"); + } + else show_info();@+break; /*recursive call*/ + default:do_nothing; /*|empty|*/ + } @/ + flush_char; /*remove |c| from the recursion history*/ + } +} + +@ The inelegant introduction of |show_info| in the code above seems better +than the alternative of using \PASCAL's strange |forward| declaration for a +procedure with parameters. The \PASCAL\ convention about dropping parameters +from a post-|forward| procedure is, frankly, so intolerable to the author +of \TeX\ that he would rather stoop to communication via a global temporary +variable. (A similar stoopidity occurred with respect to |hlist_out| and +|vlist_out| above, and it will occur with respect to |mlist_to_hlist| below.) +@^Knuth, Donald Ervin@> +@:PASCAL}{\PASCAL@> + +@p static void show_info(void) /*the reader will kindly forgive this*/ +{@+show_node_list(info(temp_ptr)); +} + +@ @<Declare procedures needed for displaying...@>= +static void print_style(int @!c) +{@+switch (c/2) { +case 0: print_esc("displaystyle");@+break; /*|display_style==0|*/ +case 1: print_esc("textstyle");@+break; /*|text_style==2|*/ +case 2: print_esc("scriptstyle");@+break; /*|script_style==4|*/ +case 3: print_esc("scriptscriptstyle");@+break; /*|script_script_style==6|*/ +default:print("Unknown style!"); +} +} + +@ @<Display choice node |p|@>= +{@+print_esc("mathchoice"); +append_char('D');show_node_list(display_mlist(p));flush_char; +append_char('T');show_node_list(text_mlist(p));flush_char; +append_char('S');show_node_list(script_mlist(p));flush_char; +append_char('s');show_node_list(script_script_mlist(p));flush_char; +} + +@ @<Display normal noad |p|@>= +{@+switch (type(p)) { +case ord_noad: print_esc("mathord");@+break; +case op_noad: print_esc("mathop");@+break; +case bin_noad: print_esc("mathbin");@+break; +case rel_noad: print_esc("mathrel");@+break; +case open_noad: print_esc("mathopen");@+break; +case close_noad: print_esc("mathclose");@+break; +case punct_noad: print_esc("mathpunct");@+break; +case inner_noad: print_esc("mathinner");@+break; +case over_noad: print_esc("overline");@+break; +case under_noad: print_esc("underline");@+break; +case vcenter_noad: print_esc("vcenter");@+break; +case radical_noad: {@+print_esc("radical");print_delimiter(left_delimiter(p)); + } @+break; +case accent_noad: {@+print_esc("accent");print_fam_and_char(accent_chr(p)); + } @+break; +case left_noad: {@+print_esc("left");print_delimiter(delimiter(p)); + } @+break; +case right_noad: {@+if (subtype(p)==normal) print_esc("right"); + else print_esc("middle"); + print_delimiter(delimiter(p)); + } +} +if (type(p) < left_noad) + {@+if (subtype(p)!=normal) + if (subtype(p)==limits) print_esc("limits"); + else print_esc("nolimits"); + print_subsidiary_data(nucleus(p),'.'); + } +print_subsidiary_data(supscr(p),'^'); +print_subsidiary_data(subscr(p),'_'); +} + +@ @<Display fraction noad |p|@>= +{@+print_esc("fraction, thickness "); +if (thickness(p)==default_code) print("= default"); +else print_scaled(thickness(p)); +if ((small_fam(left_delimiter(p))!=0)||@+ + (small_char(left_delimiter(p))!=min_quarterword)||@| + (large_fam(left_delimiter(p))!=0)||@| + (large_char(left_delimiter(p))!=min_quarterword)) + {@+print(", left-delimiter ");print_delimiter(left_delimiter(p)); + } +if ((small_fam(right_delimiter(p))!=0)||@| + (small_char(right_delimiter(p))!=min_quarterword)||@| + (large_fam(right_delimiter(p))!=0)||@| + (large_char(right_delimiter(p))!=min_quarterword)) + {@+print(", right-delimiter ");print_delimiter(right_delimiter(p)); + } +print_subsidiary_data(numerator(p),'\\'); +print_subsidiary_data(denominator(p),'/'); +} + +@ That which can be displayed can also be destroyed. + +@<Cases of |flush_node_list| that arise...@>= +case style_node: {@+free_node(p, style_node_size);goto done; + } +case choice_node: {@+flush_node_list(display_mlist(p)); + flush_node_list(text_mlist(p)); + flush_node_list(script_mlist(p)); + flush_node_list(script_script_mlist(p)); + free_node(p, style_node_size);goto done; + } +case ord_noad: case op_noad: case bin_noad: case rel_noad: case open_noad: case close_noad: case punct_noad: case inner_noad: + case radical_noad: case over_noad: case under_noad: case vcenter_noad: case accent_noad: @t@>@;@/ + {@+if (math_type(nucleus(p)) >= sub_box) + flush_node_list(info(nucleus(p))); + if (math_type(supscr(p)) >= sub_box) + flush_node_list(info(supscr(p))); + if (math_type(subscr(p)) >= sub_box) + flush_node_list(info(subscr(p))); + if (type(p)==radical_noad) free_node(p, radical_noad_size); + else if (type(p)==accent_noad) free_node(p, accent_noad_size); + else free_node(p, noad_size); + goto done; + } +case left_noad: case right_noad: {@+free_node(p, noad_size);goto done; + } +case fraction_noad: {@+flush_node_list(info(numerator(p))); + flush_node_list(info(denominator(p))); + free_node(p, fraction_noad_size);goto done; + } + +@* Subroutines for math mode. +In order to convert mlists to hlists, i.e., noads to nodes, we need several +subroutines that are conveniently dealt with now. + +Let us first introduce the macros that make it easy to get at the parameters and +other font information. A size code, which is a multiple of 16, is added to a +family number to get an index into the table of internal font numbers +for each combination of family and size. (Be alert: Size codes get +larger as the type gets smaller.) + +@d text_size 0 /*size code for the largest size in a family*/ +@d script_size 16 /*size code for the medium size in a family*/ +@d script_script_size 32 /*size code for the smallest size in a family*/ + +@<Basic printing procedures@>= +static void print_size(int @!s) +{@+if (s==text_size) print_esc("textfont"); +else if (s==script_size) print_esc("scriptfont"); +else print_esc("scriptscriptfont"); +} + +@ Before an mlist is converted to an hlist, \TeX\ makes sure that +the fonts in family~2 have enough parameters to be math-symbol +fonts, and that the fonts in family~3 have enough parameters to be +math-extension fonts. The math-symbol parameters are referred to by using the +following macros, which take a size code as their parameter; for example, +|num1(cur_size)| gives the value of the |num1| parameter for the current size. +@^parameters for symbols@> +@^font parameters@> + +@d mathsy_end(A) fam_fnt(2+A)]].sc +@d mathsy(A) font_info[A+param_base[mathsy_end +@d math_x_height mathsy(5) /*height of `\.x'*/ +@d math_quad mathsy(6) /*\.{18mu}*/ +@d num1 mathsy(8) /*numerator shift-up in display styles*/ +@d num2 mathsy(9) /*numerator shift-up in non-display, non-\.{\\atop}*/ +@d num3 mathsy(10) /*numerator shift-up in non-display \.{\\atop}*/ +@d denom1 mathsy(11) /*denominator shift-down in display styles*/ +@d denom2 mathsy(12) /*denominator shift-down in non-display styles*/ +@d sup1 mathsy(13) /*superscript shift-up in uncramped display style*/ +@d sup2 mathsy(14) /*superscript shift-up in uncramped non-display*/ +@d sup3 mathsy(15) /*superscript shift-up in cramped styles*/ +@d sub1 mathsy(16) /*subscript shift-down if superscript is absent*/ +@d sub2 mathsy(17) /*subscript shift-down if superscript is present*/ +@d sup_drop mathsy(18) /*superscript baseline below top of large box*/ +@d sub_drop mathsy(19) /*subscript baseline below bottom of large box*/ +@d delim1 mathsy(20) /*size of \.{\\atopwithdelims} delimiters + in display styles*/ +@d delim2 mathsy(21) /*size of \.{\\atopwithdelims} delimiters in non-displays*/ +@d axis_height mathsy(22) /*height of fraction lines above the baseline*/ +@d total_mathsy_params 22 + +@ The math-extension parameters have similar macros, but the size code is +omitted (since it is always |cur_size| when we refer to such parameters). +@^parameters for symbols@> +@^font parameters@> + +@d mathex(A) font_info[A+param_base[fam_fnt(3+cur_size)]].sc +@d default_rule_thickness mathex(8) /*thickness of \.{\\over} bars*/ +@d big_op_spacing1 mathex(9) /*minimum clearance above a displayed op*/ +@d big_op_spacing2 mathex(10) /*minimum clearance below a displayed op*/ +@d big_op_spacing3 mathex(11) /*minimum baselineskip above displayed op*/ +@d big_op_spacing4 mathex(12) /*minimum baselineskip below displayed op*/ +@d big_op_spacing5 mathex(13) /*padding above and below displayed limits*/ +@d total_mathex_params 13 + +@ We also need to compute the change in style between mlists and their +subsidiaries. The following macros define the subsidiary style for +an overlined nucleus (|cramped_style|), for a subscript or a superscript +(|sub_style| or |sup_style|), or for a numerator or denominator (|num_style| +or |denom_style|). + +@d cramped_style(A) 2*(A/2)+cramped /*cramp the style*/ +@d sub_style(A) 2*(A/4)+script_style+cramped /*smaller and cramped*/ +@d sup_style(A) 2*(A/4)+script_style+(A%2) /*smaller*/ +@d num_style(A) A+2-2*(A/6) /*smaller unless already script-script*/ +@d denom_style(A) 2*(A/2)+cramped+2-2*(A/6) /*smaller, cramped*/ + +@ When the style changes, the following piece of program computes associated +information: + +@<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>= +{@+if (cur_style < script_style) cur_size=text_size; +else cur_size=16*((cur_style-text_style)/2); +cur_mu=x_over_n(math_quad(cur_size), 18); +} + +@ Here is a function that returns a pointer to a rule node having a given +thickness |t|. The rule will extend horizontally to the boundary of the vlist +that eventually contains it. + +@p static pointer fraction_rule(scaled @!t) + /*construct the bar for a fraction*/ +{@+pointer p; /*the new node*/ +p=new_rule();height(p)=t;depth(p)=0;return p; +} + +@ The |overbar| function returns a pointer to a vlist box that consists of +a given box |b|, above which has been placed a kern of height |k| under a +fraction rule of thickness |t| under additional space of height |t|. + +@p static pointer overbar(pointer @!b, scaled @!k, scaled @!t) +{@+pointer p, @!q; /*nodes being constructed*/ +p=new_kern(k);link(p)=b;q=fraction_rule(t);link(q)=p; +p=new_kern(t);link(p)=q;return vpack(p, natural); +} + +@ The |var_delimiter| function, which finds or constructs a sufficiently +large delimiter, is the most interesting of the auxiliary functions that +currently concern us. Given a pointer |d| to a delimiter field in some noad, +together with a size code |s| and a vertical distance |v|, this function +returns a pointer to a box that contains the smallest variant of |d| whose +height plus depth is |v| or more. (And if no variant is large enough, it +returns the largest available variant.) In particular, this routine will +construct arbitrarily large delimiters from extensible components, if +|d| leads to such characters. + +The value returned is a box whose |shift_amount| has been set so that +the box is vertically centered with respect to the axis in the given size. +If a built-up symbol is returned, the height of the box before shifting +will be the height of its topmost component. + +@p @t\4@>@<Declare subprocedures for |var_delimiter|@>@; +static pointer var_delimiter(pointer @!d, small_number @!s, scaled @!v) +{@+ +pointer b; /*the box that will be constructed*/ +internal_font_number @!f, @!g; /*best-so-far and tentative font codes*/ +quarterword @!c, @!x, @!y; /*best-so-far and tentative character codes*/ +int @!m, @!n; /*the number of extensible pieces*/ +scaled @!u; /*height-plus-depth of a tentative character*/ +scaled @!w; /*largest height-plus-depth so far*/ +four_quarters @!q; /*character info*/ +eight_bits @!hd; /*height-depth byte*/ +four_quarters @!r; /*extensible pieces*/ +small_number @!z; /*runs through font family members*/ +bool @!large_attempt; /*are we trying the ``large'' variant?*/ +f=null_font;w=0;large_attempt=false; +z=small_fam(d);x=small_char(d); +loop@+{@+@<Look at the variants of |(z,x)|; set |f| and |c| whenever a better character +is found; |goto found| as soon as a large enough variant is encountered@>; + if (large_attempt) goto found; /*there were none large enough*/ + large_attempt=true;z=large_fam(d);x=large_char(d); + } +found: if (f!=null_font) + @<Make variable |b| point to a box for |(f,c)|@>; +else{@+b=new_null_box(); + width(b)=null_delimiter_space; /*use this width if no delimiter was found*/ + } +shift_amount(b)=half(height(b)-depth(b))-axis_height(s); +return b; +} + +@ The search process is complicated slightly by the facts that some of the +characters might not be present in some of the fonts, and they might not +be probed in increasing order of height. + +@<Look at the variants of |(z,x)|; set |f| and |c|...@>= +if ((z!=0)||(x!=min_quarterword)) + {@+z=z+s+16; + @/do@+{z=z-16;g=fam_fnt(z); + if (g!=null_font) + @<Look at the list of characters starting with |x| in font |g|; set |f| and |c| +whenever a better character is found; |goto found| as soon as a large enough variant +is encountered@>; + }@+ while (!(z < 16)); + } + +@ @<Look at the list of characters starting with |x|...@>= +{@+y=x; +if ((qo(y) >= font_bc[g])&&(qo(y) <= font_ec[g])) + {@+resume: q=char_info(g, y); + if (char_exists(q)) + {@+if (char_tag(q)==ext_tag) + {@+f=g;c=y;goto found; + } + hd=height_depth(q); + u=char_height(g, hd)+char_depth(g, hd); + if (u > w) + {@+f=g;c=y;w=u; + if (u >= v) goto found; + } + if (char_tag(q)==list_tag) + {@+y=rem_byte(q);goto resume; + } + } + } +} + +@ Here is a subroutine that creates a new box, whose list contains a +single character, and whose width includes the italic correction for +that character. The height or depth of the box will be negative, if +the height or depth of the character is negative; thus, this routine +may deliver a slightly different result than |hpack| would produce. + +@<Declare subprocedures for |var_delimiter|@>= +static pointer char_box(internal_font_number @!f, quarterword @!c) +{@+four_quarters q; +eight_bits @!hd; /*|height_depth| byte*/ +pointer @!b, @!p; /*the new box and its character node*/ +q=char_info(f, c);hd=height_depth(q); +b=new_null_box();width(b)=char_width(f, q)+char_italic(f, q); +height(b)=char_height(f, hd);depth(b)=char_depth(f, hd); +p=get_avail();character(p)=c;font(p)=f;list_ptr(b)=p;return b; +} + +@ When the following code is executed, |char_tag(q)| will be equal to +|ext_tag| if and only if a built-up symbol is supposed to be returned. + +@<Make variable |b| point to a box for |(f,c)|@>= +if (char_tag(q)==ext_tag) + @<Construct an extensible character in a new box |b|, using recipe |rem_byte(q)| +and font |f|@>@; +else b=char_box(f, c) + +@ When we build an extensible character, it's handy to have the +following subroutine, which puts a given character on top +of the characters already in box |b|: + +@<Declare subprocedures for |var_delimiter|@>= +static void stack_into_box(pointer @!b, internal_font_number @!f, + quarterword @!c) +{@+pointer p; /*new node placed into |b|*/ +p=char_box(f, c);link(p)=list_ptr(b);list_ptr(b)=p; +height(b)=height(p); +} + +@ Another handy subroutine computes the height plus depth of +a given character: + +@<Declare subprocedures for |var_delimiter|@>= +static scaled height_plus_depth(internal_font_number @!f, quarterword @!c) +{@+four_quarters q; +eight_bits @!hd; /*|height_depth| byte*/ +q=char_info(f, c);hd=height_depth(q); +return char_height(f, hd)+char_depth(f, hd); +} + +@ @<Construct an extensible...@>= +{@+b=new_null_box(); +type(b)=vlist_node; +r=font_info[exten_base[f]+rem_byte(q)].qqqq;@/ +@<Compute the minimum suitable height, |w|, and the corresponding number of extension +steps, |n|; also set |width(b)|@>; +c=ext_bot(r); +if (c!=min_quarterword) stack_into_box(b, f, c); +c=ext_rep(r); +for (m=1; m<=n; m++) stack_into_box(b, f, c); +c=ext_mid(r); +if (c!=min_quarterword) + {@+stack_into_box(b, f, c);c=ext_rep(r); + for (m=1; m<=n; m++) stack_into_box(b, f, c); + } +c=ext_top(r); +if (c!=min_quarterword) stack_into_box(b, f, c); +depth(b)=w-height(b); +} + +@ The width of an extensible character is the width of the repeatable +module. If this module does not have positive height plus depth, +we don't use any copies of it, otherwise we use as few as possible +(in groups of two if there is a middle part). + +@<Compute the minimum suitable height, |w|, and...@>= +c=ext_rep(r);u=height_plus_depth(f, c); +w=0;q=char_info(f, c);width(b)=char_width(f, q)+char_italic(f, q);@/ +c=ext_bot(r);@+if (c!=min_quarterword) w=w+height_plus_depth(f, c); +c=ext_mid(r);@+if (c!=min_quarterword) w=w+height_plus_depth(f, c); +c=ext_top(r);@+if (c!=min_quarterword) w=w+height_plus_depth(f, c); +n=0; +if (u > 0) while (w < v) + {@+w=w+u;incr(n); + if (ext_mid(r)!=min_quarterword) w=w+u; + } + +@ The next subroutine is much simpler; it is used for numerators and +denominators of fractions as well as for displayed operators and +their limits above and below. It takes a given box~|b| and +changes it so that the new box is centered in a box of width~|w|. +The centering is done by putting \.{\\hss} glue at the left and right +of the list inside |b|, then packaging the new box; thus, the +actual box might not really be centered, if it already contains +infinite glue. + +The given box might contain a single character whose italic correction +has been added to the width of the box; in this case a compensating +kern is inserted. + +@p static pointer rebox(pointer @!b, scaled @!w) +{@+pointer p; /*temporary register for list manipulation*/ +internal_font_number @!f; /*font in a one-character box*/ +scaled @!v; /*width of a character without italic correction*/ +if ((width(b)!=w)&&(list_ptr(b)!=null)) + {@+if (type(b)==vlist_node) b=hpack(b, natural); + p=list_ptr(b); + if ((is_char_node(p))&&(link(p)==null)) + {@+f=font(p);v=char_width(f, char_info(f, character(p))); + if (v!=width(b)) link(p)=new_kern(width(b)-v); + } + list_ptr(b)=null; flush_node_list(b); + b=new_glue(ss_glue);link(b)=p; + while (link(p)!=null) p=link(p); + link(p)=new_glue(ss_glue); + return hpack(b, w, 0, 0, exactly); + } +else{@+width(b)=w;return b; + } +} + +@ Here is a subroutine that creates a new glue specification from another +one that is expressed in `\.{mu}', given the value of the math unit. + +@d mu_mult(A) nx_plus_y(n, A, xn_over_d(A, f, 0200000)) + +@p static pointer math_glue(pointer @!g, scaled @!m) +{@+pointer p; /*the new glue specification*/ +int @!n; /*integer part of |m|*/ +scaled @!f; /*fraction part of |m|*/ +n=x_over_n(m, 0200000);f=rem;@/ +if (f < 0) + {@+decr(n);f=f+0200000; + } +p=get_node(glue_spec_size); +width(p)=mu_mult(width(g)); /*convert \.{mu} to \.{pt}*/ +stretch_order(p)=stretch_order(g); +if (stretch_order(p)==normal) stretch(p)=mu_mult(stretch(g)); +else stretch(p)=stretch(g); +shrink_order(p)=shrink_order(g); +if (shrink_order(p)==normal) shrink(p)=mu_mult(shrink(g)); +else shrink(p)=shrink(g); +return p; +} + +@ The |math_kern| subroutine removes |mu_glue| from a kern node, given +the value of the math unit. + +@p static void math_kern(pointer @!p, scaled @!m) +{@+int @!n; /*integer part of |m|*/ +scaled @!f; /*fraction part of |m|*/ +if (subtype(p)==mu_glue) + {@+n=x_over_n(m, 0200000);f=rem;@/ + if (f < 0) + {@+decr(n);f=f+0200000; + } + width(p)=mu_mult(width(p));subtype(p)=explicit; + } +} + +@ Sometimes it is necessary to destroy an mlist. The following +subroutine empties the current list, assuming that |abs(mode)==mmode|. + +@p static void flush_math(void) +{@+flush_node_list(link(head));flush_node_list(incompleat_noad); +link(head)=null;tail=head;incompleat_noad=null; +} + +@* Typesetting math formulas. +\TeX's most important routine for dealing with formulas is called +|mlist_to_hlist|. After a formula has been scanned and represented as an +mlist, this routine converts it to an hlist that can be placed into a box +or incorporated into the text of a paragraph. There are three implicit +parameters, passed in global variables: |cur_mlist| points to the first +node or noad in the given mlist (and it might be |null|); |cur_style| is a +style code; and |mlist_penalties| is |true| if penalty nodes for potential +line breaks are to be inserted into the resulting hlist. After +|mlist_to_hlist| has acted, |link(temp_head)| points to the translated hlist. + +Since mlists can be inside mlists, the procedure is recursive. And since this +is not part of \TeX's inner loop, the program has been written in a manner +that stresses compactness over efficiency. +@^recursion@> + +@<Glob...@>= +static pointer @!cur_mlist; /*beginning of mlist to be translated*/ +static small_number @!cur_style; /*style code at current place in the list*/ +static small_number @!cur_size; /*size code corresponding to |cur_style|*/ +static scaled @!cur_mu; /*the math unit width corresponding to |cur_size|*/ +static bool @!mlist_penalties; /*should |mlist_to_hlist| insert penalties?*/ + +@ The recursion in |mlist_to_hlist| is due primarily to a subroutine +called |clean_box| that puts a given noad field into a box using a given +math style; |mlist_to_hlist| can call |clean_box|, which can call +|mlist_to_hlist|. +@^recursion@> + +The box returned by |clean_box| is ``clean'' in the +sense that its |shift_amount| is zero. + +@p static void mlist_to_hlist(void);@/ +static pointer clean_box(pointer @!p, small_number @!s) +{@+ +pointer q; /*beginning of a list to be boxed*/ +small_number @!save_style; /*|cur_style| to be restored*/ +pointer @!x; /*box to be returned*/ +pointer @!r; /*temporary pointer*/ +switch (math_type(p)) { +case math_char: {@+cur_mlist=new_noad();mem[nucleus(cur_mlist)]=mem[p]; + } @+break; +case sub_box: {@+q=info(p);goto found; + } +case sub_mlist: cur_mlist=info(p);@+break; +default:{@+q=new_null_box();goto found; + } +} @/ +save_style=cur_style;cur_style=s;mlist_penalties=false;@/ +mlist_to_hlist();q=link(temp_head); /*recursive call*/ +cur_style=save_style; /*restore the style*/ +@<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>; +found: if (is_char_node(q)||(q==null)) x=hpack(q, natural); + else if ((link(q)==null)&&(type(q) <= vlist_node)&&(shift_amount(q)==0)) + x=q; /*it's already clean*/ + else x=hpack(q, natural); +@<Simplify a trivial box@>; +return x; +} + +@ Here we save memory space in a common case. + +@<Simplify a trivial box@>= +q=list_ptr(x); +if (is_char_node(q)) + {@+r=link(q); + if (r!=null) if (link(r)==null) if (!is_char_node(r)) + if (type(r)==kern_node) /*unneeded italic correction*/ + {@+free_node(r, small_node_size);link(q)=null; + } + } + +@ It is convenient to have a procedure that converts a |math_char| +field to an ``unpacked'' form. The |fetch| routine sets |cur_f|, |cur_c|, +and |cur_i| to the font code, character code, and character information bytes of +a given noad field. It also takes care of issuing error messages for +nonexistent characters; in such cases, |char_exists(cur_i)| will be |false| +after |fetch| has acted, and the field will also have been reset to |empty|. + +@p static void fetch(pointer @!a) /*unpack the |math_char| field |a|*/ +{@+cur_c=character(a);cur_f=fam_fnt(fam(a)+cur_size); +if (cur_f==null_font) + @<Complain about an undefined family and set |cur_i| null@>@; +else{@+if ((qo(cur_c) >= font_bc[cur_f])&&(qo(cur_c) <= font_ec[cur_f])) + cur_i=char_info(cur_f, cur_c); + else cur_i=null_character; + if (!(char_exists(cur_i))) + {@+char_warning(cur_f, qo(cur_c)); + math_type(a)=empty; + } + } +} + +@ @<Complain about an undefined family...@>= +{@+print_err("");print_size(cur_size);print_char(' '); +print_int(fam(a));print(" is undefined (character "); +print_ASCII(qo(cur_c));print_char(')'); +help4("Somewhere in the math formula just ended, you used the",@/ +"stated character from an undefined font family. For example,",@/ +"plain TeX doesn't allow \\it or \\sl in subscripts. Proceed,",@/ +"and I'll try to forget that I needed that character."); +error();cur_i=null_character;math_type(a)=empty; +} + +@ The outputs of |fetch| are placed in global variables. + +@<Glob...@>= +static internal_font_number @!cur_f; /*the |font| field of a |math_char|*/ +static quarterword @!cur_c; /*the |character| field of a |math_char|*/ +static four_quarters @!cur_i; /*the |char_info| of a |math_char|, + or a lig/kern instruction*/ + +@ We need to do a lot of different things, so |mlist_to_hlist| makes two +passes over the given mlist. + +The first pass does most of the processing: It removes ``mu'' spacing from +glue, it recursively evaluates all subsidiary mlists so that only the +top-level mlist remains to be handled, it puts fractions and square roots +and such things into boxes, it attaches subscripts and superscripts, and +it computes the overall height and depth of the top-level mlist so that +the size of delimiters for a |left_noad| and a |right_noad| will be known. +The hlist resulting from each noad is recorded in that noad's |new_hlist| +field, an integer field that replaces the |nucleus| or |thickness|. +@^recursion@> + +The second pass eliminates all noads and inserts the correct glue and +penalties between nodes. + +@d new_hlist(A) mem[nucleus(A)].i /*the translation of an mlist*/ + +@ Here is the overall plan of |mlist_to_hlist|, and the list of its +local variables. + +@p @t\4@>@<Declare math construction procedures@>@; +static void mlist_to_hlist(void) +{@+ + +pointer mlist; /*beginning of the given list*/ +bool @!penalties; /*should penalty nodes be inserted?*/ +small_number @!style; /*the given style*/ +small_number @!save_style; /*holds |cur_style| during recursion*/ +pointer @!q; /*runs through the mlist*/ +pointer @!r; /*the most recent noad preceding |q|*/ +small_number @!r_type; /*the |type| of noad |r|, or |op_noad| if |r==null|*/ +small_number @!t; /*the effective |type| of noad |q| during the second pass*/ +pointer @!p, @!x, @!y, @!z; /*temporary registers for list construction*/ +int @!pen; /*a penalty to be inserted*/ +small_number @!s; /*the size of a noad to be deleted*/ +scaled @!max_h, @!max_d; /*maximum height and depth of the list translated so far*/ +scaled @!delta; /*offset between subscript and superscript*/ +mlist=cur_mlist;penalties=mlist_penalties; +style=cur_style; /*tuck global parameters away as local variables*/ +q=mlist;r=null;r_type=op_noad;max_h=0;max_d=0; +@<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>; +while (q!=null) @<Process node-or-noad |q| as much as possible in preparation for +the second pass of |mlist_to_hlist|, then move to the next item in the mlist@>; +@<Convert \(a)a final |bin_noad| to an |ord_noad|@>; +@<Make a second pass over the mlist, removing all noads and inserting the proper spacing +and penalties@>; +} + +@ We use the fact that no character nodes appear in an mlist, hence +the field |type(q)| is always present. + +@<Process node-or-noad...@>= +{@+@<Do first-pass processing based on |type(q)|; |goto done_with_noad| if a noad +has been fully processed, |goto check_dimensions| if it has been translated into |new_hlist(q)|, +or |goto done_with_node| if a node has been fully processed@>; +check_dimensions: z=hpack(new_hlist(q), natural); +if (height(z) > max_h) max_h=height(z); +if (depth(z) > max_d) max_d=depth(z); +list_ptr(z)=null; flush_node_list(z); +done_with_noad: r=q;r_type=type(r); +if (r_type==right_noad) + {@+r_type=left_noad;cur_style=style;@<Set up the values...@>; + } +done_with_node: q=link(q); +} + +@ One of the things we must do on the first pass is change a |bin_noad| to +an |ord_noad| if the |bin_noad| is not in the context of a binary operator. +The values of |r| and |r_type| make this fairly easy. + +@<Do first-pass processing...@>= +reswitch: delta=0; +switch (type(q)) { +case bin_noad: switch (r_type) { + case bin_noad: case op_noad: case rel_noad: case open_noad: case punct_noad: case left_noad: + {@+type(q)=ord_noad;goto reswitch; + } + default:do_nothing; + } @+break; +case rel_noad: case close_noad: case punct_noad: case right_noad: {@+@t@>@;@/ + @<Convert \(a)a final |bin_noad| to an |ord_noad|@>; + if (type(q)==right_noad) goto done_with_noad; + } @+break; +@t\4@>@<Cases for noads that can follow a |bin_noad|@>@; +@t\4@>@<Cases for nodes that can appear in an mlist, after which we |goto done_with_node|@>@; +default:confusion("mlist1"); +@:this can't happen mlist1}{\quad mlist1@> +} @/ +@<Convert \(n)|nucleus(q)| to an hlist and attach the sub/superscripts@>@; + +@ @<Convert \(a)a final |bin_noad| to an |ord_noad|@>= +if (r_type==bin_noad) type(r)=ord_noad + +@ @<Cases for nodes that can appear in an mlist...@>= +case style_node: {@+cur_style=subtype(q); + @<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>; + goto done_with_node; + } +case choice_node: @<Change this node to a style node followed by the correct choice, +then |goto done_with_node|@>@; +case ins_node: case mark_node: case adjust_node: + case whatsit_node: case penalty_node: case disc_node: goto done_with_node; +case rule_node: {@+if (height(q) > max_h) max_h=height(q); + if (depth(q) > max_d) max_d=depth(q);goto done_with_node; + } +case glue_node: {@+@<Convert \(m)math glue to ordinary glue@>; + goto done_with_node; + } +case kern_node: {@+math_kern(q, cur_mu);goto done_with_node; + } + +@ @d choose_mlist(A) {@+p=A(q);A(q)=null;@+} + +@<Change this node to a style node...@>= +{@+switch (cur_style/2) { +case 0: choose_mlist(display_mlist)@;@+break; /*|display_style==0|*/ +case 1: choose_mlist(text_mlist)@;@+break; /*|text_style==2|*/ +case 2: choose_mlist(script_mlist)@;@+break; /*|script_style==4|*/ +case 3: choose_mlist(script_script_mlist); /*|script_script_style==6|*/ +} /*there are no other cases*/ +flush_node_list(display_mlist(q)); +flush_node_list(text_mlist(q)); +flush_node_list(script_mlist(q)); +flush_node_list(script_script_mlist(q));@/ +type(q)=style_node;subtype(q)=cur_style;width(q)=0;depth(q)=0; +if (p!=null) + {@+z=link(q);link(q)=p; + while (link(p)!=null) p=link(p); + link(p)=z; + } +goto done_with_node; +} + +@ Conditional math glue (`\.{\\nonscript}') results in a |glue_node| +pointing to |zero_glue|, with |subtype(q)==cond_math_glue|; in such a case +the node following will be eliminated if it is a glue or kern node and if the +current size is different from |text_size|. Unconditional math glue +(`\.{\\muskip}') is converted to normal glue by multiplying the dimensions +by |cur_mu|. +@!@:non\_script\_}{\.{\\nonscript} primitive@> + +@<Convert \(m)math glue to ordinary glue@>= +if (subtype(q)==mu_glue) + {@+x=glue_ptr(q); + y=math_glue(x, cur_mu);delete_glue_ref(x);glue_ptr(q)=y; + subtype(q)=normal; + } +else if ((cur_size!=text_size)&&(subtype(q)==cond_math_glue)) + {@+p=link(q); + if (p!=null) if ((type(p)==glue_node)||(type(p)==kern_node)) + {@+link(q)=link(p);link(p)=null;flush_node_list(p); + } + } + +@ @<Cases for noads that can follow a |bin_noad|@>= +case left_noad: goto done_with_noad; +case fraction_noad: {@+make_fraction(q);goto check_dimensions; + } +case op_noad: {@+delta=make_op(q); + if (subtype(q)==limits) goto check_dimensions; + } @+break; +case ord_noad: make_ord(q);@+break; +case open_noad: case inner_noad: do_nothing;@+break; +case radical_noad: make_radical(q);@+break; +case over_noad: make_over(q);@+break; +case under_noad: make_under(q);@+break; +case accent_noad: make_math_accent(q);@+break; +case vcenter_noad: make_vcenter(q);@+break; + +@ Most of the actual construction work of |mlist_to_hlist| is done +by procedures with names +like |make_fraction|, |make_radical|, etc. To illustrate +the general setup of such procedures, let's begin with a couple of +simple ones. + +@<Declare math...@>= +static void make_over(pointer @!q) +{@+info(nucleus(q))=@| + overbar(clean_box(nucleus(q), cramped_style(cur_style)),@| + 3*default_rule_thickness, default_rule_thickness); +math_type(nucleus(q))=sub_box; +} + +@ @<Declare math...@>= +static void make_under(pointer @!q) +{@+pointer p, @!x, @!y; /*temporary registers for box construction*/ +scaled @!delta; /*overall height plus depth*/ +x=clean_box(nucleus(q), cur_style); +p=new_kern(3*default_rule_thickness);link(x)=p; +link(p)=fraction_rule(default_rule_thickness); +y=vpack(x, natural); +delta=height(y)+depth(y)+default_rule_thickness; +height(y)=height(x);depth(y)=delta-height(y); +info(nucleus(q))=y;math_type(nucleus(q))=sub_box; +} + +@ @<Declare math...@>= +static void make_vcenter(pointer @!q) +{@+pointer v; /*the box that should be centered vertically*/ +scaled @!delta; /*its height plus depth*/ +v=info(nucleus(q)); +if (type(v)!=vlist_node) confusion("vcenter"); +@:this can't happen vcenter}{\quad vcenter@> +delta=height(v)+depth(v); +height(v)=axis_height(cur_size)+half(delta); +depth(v)=delta-height(v); +} + +@ According to the rules in the \.{DVI} file specifications, we ensure alignment +@^square roots@> +between a square root sign and the rule above its nucleus by assuming that the +baseline of the square-root symbol is the same as the bottom of the rule. The +height of the square-root symbol will be the thickness of the rule, and the +depth of the square-root symbol should exceed or equal the height-plus-depth +of the nucleus plus a certain minimum clearance~|clr|. The symbol will be +placed so that the actual clearance is |clr| plus half the excess. + +@<Declare math...@>= +static void make_radical(pointer @!q) +{@+pointer x, @!y; /*temporary registers for box construction*/ +scaled @!delta, @!clr; /*dimensions involved in the calculation*/ +x=clean_box(nucleus(q), cramped_style(cur_style)); +if (cur_style < text_style) /*display style*/ + clr=default_rule_thickness+(abs(math_x_height(cur_size))/4); +else{@+clr=default_rule_thickness;clr=clr+(abs(clr)/4); + } +y=var_delimiter(left_delimiter(q), cur_size, height(x)+depth(x)+clr+ + default_rule_thickness); +delta=depth(y)-(height(x)+depth(x)+clr); +if (delta > 0) clr=clr+half(delta); /*increase the actual clearance*/ +shift_amount(y)=-(height(x)+clr); +link(y)=overbar(x, clr, height(y)); +info(nucleus(q))=hpack(y, natural);math_type(nucleus(q))=sub_box; +} + +@ Slants are not considered when placing accents in math mode. The accenter is +centered over the accentee, and the accent width is treated as zero with +respect to the size of the final box. + +@<Declare math...@>= +static void make_math_accent(pointer @!q) +{@+ +pointer p, @!x, @!y; /*temporary registers for box construction*/ +int @!a; /*address of lig/kern instruction*/ +quarterword @!c; /*accent character*/ +internal_font_number @!f; /*its font*/ +four_quarters @!i; /*its |char_info|*/ +scaled @!s; /*amount to skew the accent to the right*/ +scaled @!h; /*height of character being accented*/ +scaled @!delta; /*space to remove between accent and accentee*/ +scaled @!w; /*width of the accentee, not including sub/superscripts*/ +fetch(accent_chr(q)); +if (char_exists(cur_i)) + {@+i=cur_i;c=cur_c;f=cur_f;@/ + @<Compute the amount of skew@>; + x=clean_box(nucleus(q), cramped_style(cur_style));w=width(x);h=height(x); + @<Switch to a larger accent if available and appropriate@>; + if (h < x_height(f)) delta=h;@+else delta=x_height(f); + if ((math_type(supscr(q))!=empty)||(math_type(subscr(q))!=empty)) + if (math_type(nucleus(q))==math_char) + @<Swap the subscript and superscript into box |x|@>; + y=char_box(f, c); + shift_amount(y)=s+half(w-width(y)); + width(y)=0;p=new_kern(-delta);link(p)=x;link(y)=p; + y=vpack(y, natural);width(y)=width(x); + if (height(y) < h) @<Make the height of box |y| equal to |h|@>; + info(nucleus(q))=y; + math_type(nucleus(q))=sub_box; + } +} + +@ @<Make the height of box |y|...@>= +{@+p=new_kern(h-height(y));link(p)=list_ptr(y);list_ptr(y)=p; +height(y)=h; +} + +@ @<Switch to a larger accent if available and appropriate@>= +loop@+{@+if (char_tag(i)!=list_tag) goto done; + y=rem_byte(i); + i=char_info(f, y); + if (!char_exists(i)) goto done; + if (char_width(f, i) > w) goto done; + c=y; + } +done: + +@ @<Compute the amount of skew@>= +s=0; +if (math_type(nucleus(q))==math_char) + {@+fetch(nucleus(q)); + if (char_tag(cur_i)==lig_tag) + {@+a=lig_kern_start(cur_f, cur_i); + cur_i=font_info[a].qqqq; + if (skip_byte(cur_i) > stop_flag) + {@+a=lig_kern_restart(cur_f, cur_i); + cur_i=font_info[a].qqqq; + } + loop@+{@+if (qo(next_char(cur_i))==skew_char[cur_f]) + {@+if (op_byte(cur_i) >= kern_flag) + if (skip_byte(cur_i) <= stop_flag) s=char_kern(cur_f, cur_i); + goto done1; + } + if (skip_byte(cur_i) >= stop_flag) goto done1; + a=a+qo(skip_byte(cur_i))+1; + cur_i=font_info[a].qqqq; + } + } + } +done1: + +@ @<Swap the subscript and superscript into box |x|@>= +{@+flush_node_list(x);x=new_noad(); +mem[nucleus(x)]=mem[nucleus(q)]; +mem[supscr(x)]=mem[supscr(q)]; +mem[subscr(x)]=mem[subscr(q)];@/ +mem[supscr(q)].hh=empty_field; +mem[subscr(q)].hh=empty_field;@/ +math_type(nucleus(q))=sub_mlist;info(nucleus(q))=x; +x=clean_box(nucleus(q), cur_style);delta=delta+height(x)-h;h=height(x); +} + +@ The |make_fraction| procedure is a bit different because it sets +|new_hlist(q)| directly rather than making a sub-box. + +@<Declare math...@>= +static void make_fraction(pointer @!q) +{@+pointer p, @!v, @!x, @!y, @!z; /*temporary registers for box construction*/ +scaled @!delta, @!delta1, @!delta2, @!shift_up, @!shift_down, @!clr; + /*dimensions for box calculations*/ +if (thickness(q)==default_code) thickness(q)=default_rule_thickness; +@<Create equal-width boxes |x| and |z| for the numerator and denominator, and compute +the default amounts |shift_up| and |shift_down| by which they are displaced from the +baseline@>; +if (thickness(q)==0) @<Adjust \(s)|shift_up| and |shift_down| for the case of no fraction +line@>@; +else@<Adjust \(s)|shift_up| and |shift_down| for the case of a fraction line@>; +@<Construct a vlist box for the fraction, according to |shift_up| and |shift_down|@>; +@<Put the \(f)fraction into a box with its delimiters, and make |new_hlist(q)| point +to it@>; +} + +@ @<Create equal-width boxes |x| and |z| for the numerator and denom...@>= +x=clean_box(numerator(q), num_style(cur_style)); +z=clean_box(denominator(q), denom_style(cur_style)); +if (width(x) < width(z)) x=rebox(x, width(z)); +else z=rebox(z, width(x)); +if (cur_style < text_style) /*display style*/ + {@+shift_up=num1(cur_size);shift_down=denom1(cur_size); + } +else{@+shift_down=denom2(cur_size); + if (thickness(q)!=0) shift_up=num2(cur_size); + else shift_up=num3(cur_size); + } + +@ The numerator and denominator must be separated by a certain minimum +clearance, called |clr| in the following program. The difference between +|clr| and the actual clearance is |2 delta|. + +@<Adjust \(s)|shift_up| and |shift_down| for the case of no fraction line@>= +{@+if (cur_style < text_style) clr=7*default_rule_thickness; +else clr=3*default_rule_thickness; +delta=half(clr-((shift_up-depth(x))-(height(z)-shift_down))); +if (delta > 0) + {@+shift_up=shift_up+delta; + shift_down=shift_down+delta; + } +} + +@ In the case of a fraction line, the minimum clearance depends on the actual +thickness of the line. + +@<Adjust \(s)|shift_up| and |shift_down| for the case of a fraction line@>= +{@+if (cur_style < text_style) clr=3*thickness(q); +else clr=thickness(q); +delta=half(thickness(q)); +delta1=clr-((shift_up-depth(x))-(axis_height(cur_size)+delta)); +delta2=clr-((axis_height(cur_size)-delta)-(height(z)-shift_down)); +if (delta1 > 0) shift_up=shift_up+delta1; +if (delta2 > 0) shift_down=shift_down+delta2; +} + +@ @<Construct a vlist box for the fraction...@>= +v=new_null_box();type(v)=vlist_node; +height(v)=shift_up+height(x);depth(v)=depth(z)+shift_down; +width(v)=width(x); /*this also equals |width(z)|*/ +if (thickness(q)==0) + {@+p=new_kern((shift_up-depth(x))-(height(z)-shift_down)); + link(p)=z; + } +else{@+y=fraction_rule(thickness(q));@/ + p=new_kern((axis_height(cur_size)-delta)-@|(height(z)-shift_down));@/ + link(y)=p;link(p)=z;@/ + p=new_kern((shift_up-depth(x))-(axis_height(cur_size)+delta)); + link(p)=y; + } +link(x)=p;list_ptr(v)=x + +@ @<Put the \(f)fraction into a box with its delimiters...@>= +if (cur_style < text_style) delta=delim1(cur_size); +else delta=delim2(cur_size); +x=var_delimiter(left_delimiter(q), cur_size, delta);link(x)=v;@/ +z=var_delimiter(right_delimiter(q), cur_size, delta);link(v)=z;@/ +new_hlist(q)=hpack(x, natural) + +@ If the nucleus of an |op_noad| is a single character, it is to be +centered vertically with respect to the axis, after first being enlarged +(via a character list in the font) if we are in display style. The normal +convention for placing displayed limits is to put them above and below the +operator in display style. + +The italic correction is removed from the character if there is a subscript +and the limits are not being displayed. The |make_op| +routine returns the value that should be used as an offset between +subscript and superscript. + +After |make_op| has acted, |subtype(q)| will be |limits| if and only if +the limits have been set above and below the operator. In that case, +|new_hlist(q)| will already contain the desired final box. + +@<Declare math...@>= +static scaled make_op(pointer @!q) +{@+scaled delta; /*offset between subscript and superscript*/ +pointer @!p, @!v, @!x, @!y, @!z; /*temporary registers for box construction*/ +quarterword @!c;@+four_quarters @!i; /*registers for character examination*/ +scaled @!shift_up, @!shift_down; /*dimensions for box calculation*/ +if ((subtype(q)==normal)&&(cur_style < text_style)) + subtype(q)=limits; +if (math_type(nucleus(q))==math_char) + {@+fetch(nucleus(q)); + if ((cur_style < text_style)&&(char_tag(cur_i)==list_tag)) /*make it larger*/ + {@+c=rem_byte(cur_i);i=char_info(cur_f, c); + if (char_exists(i)) + {@+cur_c=c;cur_i=i;character(nucleus(q))=c; + } + } + delta=char_italic(cur_f, cur_i);x=clean_box(nucleus(q), cur_style); + if ((math_type(subscr(q))!=empty)&&(subtype(q)!=limits)) + width(x)=width(x)-delta; /*remove italic correction*/ + shift_amount(x)=half(height(x)-depth(x))-axis_height(cur_size); + /*center vertically*/ + math_type(nucleus(q))=sub_box;info(nucleus(q))=x; + } +else delta=0; +if (subtype(q)==limits) + @<Construct a box with limits above and below it, skewed by |delta|@>; +return delta; +} + +@ The following program builds a vlist box |v| for displayed limits. The +width of the box is not affected by the fact that the limits may be skewed. + +@<Construct a box with limits above and below it...@>= +{@+x=clean_box(supscr(q), sup_style(cur_style)); +y=clean_box(nucleus(q), cur_style); +z=clean_box(subscr(q), sub_style(cur_style)); +v=new_null_box();type(v)=vlist_node;width(v)=width(y); +if (width(x) > width(v)) width(v)=width(x); +if (width(z) > width(v)) width(v)=width(z); +x=rebox(x, width(v));y=rebox(y, width(v));z=rebox(z, width(v));@/ +shift_amount(x)=half(delta);shift_amount(z)=-shift_amount(x); +height(v)=height(y);depth(v)=depth(y); +@<Attach the limits to |y| and adjust |height(v)|, |depth(v)| to account for their +presence@>; +new_hlist(q)=v; +} + +@ We use |shift_up| and |shift_down| in the following program for the +amount of glue between the displayed operator |y| and its limits |x| and +|z|. The vlist inside box |v| will consist of |x| followed by |y| followed +by |z|, with kern nodes for the spaces between and around them. + +@<Attach the limits to |y| and adjust |height(v)|, |depth(v)|...@>= +if (math_type(supscr(q))==empty) + {@+list_ptr(x)=null; flush_node_list(x);list_ptr(v)=y; + } +else{@+shift_up=big_op_spacing3-depth(x); + if (shift_up < big_op_spacing1) shift_up=big_op_spacing1; + p=new_kern(shift_up);link(p)=y;link(x)=p;@/ + p=new_kern(big_op_spacing5);link(p)=x;list_ptr(v)=p; + height(v)=height(v)+big_op_spacing5+height(x)+depth(x)+shift_up; + } +if (math_type(subscr(q))==empty)@/ + {@+list_ptr(z)=null;@+flush_node_list(z);@+} +else{@+shift_down=big_op_spacing4-height(z); + if (shift_down < big_op_spacing2) shift_down=big_op_spacing2; + p=new_kern(shift_down);link(y)=p;link(p)=z;@/ + p=new_kern(big_op_spacing5);link(z)=p; + depth(v)=depth(v)+big_op_spacing5+height(z)+depth(z)+shift_down; + } + +@ A ligature found in a math formula does not create a |ligature_node|, because +there is no question of hyphenation afterwards; the ligature will simply be +stored in an ordinary |char_node|, after residing in an |ord_noad|. + +The |math_type| is converted to |math_text_char| here if we would not want to +apply an italic correction to the current character unless it belongs +to a math font (i.e., a font with |space==0|). + +No boundary characters enter into these ligatures. + +@<Declare math...@>= +static void make_ord(pointer @!q) +{@+ +int a; /*address of lig/kern instruction*/ +pointer @!p, @!r; /*temporary registers for list manipulation*/ +restart: @t@>@;@/ +if (math_type(subscr(q))==empty) if (math_type(supscr(q))==empty) + if (math_type(nucleus(q))==math_char) + {@+p=link(q); + if (p!=null) if ((type(p) >= ord_noad)&&(type(p) <= punct_noad)) + if (math_type(nucleus(p))==math_char) + if (fam(nucleus(p))==fam(nucleus(q))) + {@+math_type(nucleus(q))=math_text_char; + fetch(nucleus(q)); + if (char_tag(cur_i)==lig_tag) + {@+a=lig_kern_start(cur_f, cur_i); + cur_c=character(nucleus(p)); + cur_i=font_info[a].qqqq; + if (skip_byte(cur_i) > stop_flag) + {@+a=lig_kern_restart(cur_f, cur_i); + cur_i=font_info[a].qqqq; + } + loop@+{@+@<If instruction |cur_i| is a kern with |cur_c|, attach the kern +after~|q|; or if it is a ligature with |cur_c|, combine noads |q| and~|p| appropriately; +then |return| if the cursor has moved past a noad, or |goto restart|@>; + if (skip_byte(cur_i) >= stop_flag) return; + a=a+qo(skip_byte(cur_i))+1; + cur_i=font_info[a].qqqq; + } + } + } + } +} + +@ Note that a ligature between an |ord_noad| and another kind of noad +is replaced by an |ord_noad|, when the two noads collapse into one. +But we could make a parenthesis (say) change shape when it follows +certain letters. Presumably a font designer will define such +ligatures only when this convention makes sense. + +\chardef\@@='174 % vertical line to indicate character retention + +@<If instruction |cur_i| is a kern with |cur_c|,...@>= +if (next_char(cur_i)==cur_c) if (skip_byte(cur_i) <= stop_flag) + if (op_byte(cur_i) >= kern_flag) + {@+p=new_kern(char_kern(cur_f, cur_i)); + link(p)=link(q);link(q)=p;return; + } + else{@+check_interrupt; /*allow a way out of infinite ligature loop*/ + switch (op_byte(cur_i)) { + case qi(1): case qi(5): character(nucleus(q))=rem_byte(cur_i);@+break; /*\.{=:\@@}, \.{=:\@@>}*/ + case qi(2): case qi(6): character(nucleus(p))=rem_byte(cur_i);@+break; /*\.{\@@=:}, \.{\@@=:>}*/ + case qi(3): case qi(7): case qi(11): {@+r=new_noad(); /*\.{\@@=:\@@}, \.{\@@=:\@@>}, \.{\@@=:\@@>>}*/ + character(nucleus(r))=rem_byte(cur_i); + fam(nucleus(r))=fam(nucleus(q));@/ + link(q)=r;link(r)=p; + if (op_byte(cur_i) < qi(11)) math_type(nucleus(r))=math_char; + else math_type(nucleus(r))=math_text_char; /*prevent combination*/ + } @+break; + default:{@+link(q)=link(p); + character(nucleus(q))=rem_byte(cur_i); /*\.{=:}*/ + mem[subscr(q)]=mem[subscr(p)];mem[supscr(q)]=mem[supscr(p)];@/ + free_node(p, noad_size); + } + } + if (op_byte(cur_i) > qi(3)) return; + math_type(nucleus(q))=math_char;goto restart; + } + +@ When we get to the following part of the program, we have ``fallen through'' +from cases that did not lead to |check_dimensions| or |done_with_noad| or +|done_with_node|. Thus, |q|~points to a noad whose nucleus may need to be +converted to an hlist, and whose subscripts and superscripts need to be +appended if they are present. + +If |nucleus(q)| is not a |math_char|, the variable |delta| is the amount +by which a superscript should be moved right with respect to a subscript +when both are present. +@^subscripts@> +@^superscripts@> + +@<Convert \(n)|nucleus(q)| to an hlist and attach the sub/superscripts@>= +switch (math_type(nucleus(q))) { +case math_char: case math_text_char: + @<Create a character node |p| for |nucleus(q)|, possibly followed by a kern node +for the italic correction, and set |delta| to the italic correction if a subscript +is present@>@;@+break; +case empty: p=null;@+break; +case sub_box: p=info(nucleus(q));@+break; +case sub_mlist: {@+cur_mlist=info(nucleus(q));save_style=cur_style; + mlist_penalties=false;mlist_to_hlist(); /*recursive call*/ +@^recursion@> + cur_style=save_style;@<Set up the values...@>; + p=hpack(link(temp_head), natural); + } @+break; +default:confusion("mlist2"); +@:this can't happen mlist2}{\quad mlist2@> +} @/ +new_hlist(q)=p; +if ((math_type(subscr(q))==empty)&&(math_type(supscr(q))==empty)) + goto check_dimensions; +make_scripts(q, delta) + +@ @<Create a character node |p| for |nucleus(q)|...@>= +{@+fetch(nucleus(q)); +if (char_exists(cur_i)) + {@+delta=char_italic(cur_f, cur_i);p=new_character(cur_f, qo(cur_c)); + if ((math_type(nucleus(q))==math_text_char)&&(space(cur_f)!=0)) + delta=0; /*no italic correction in mid-word of text font*/ + if ((math_type(subscr(q))==empty)&&(delta!=0)) + {@+link(p)=new_kern(delta);delta=0; + } + } +else p=null; +} + +@ The purpose of |make_scripts(q, delta)| is to attach the subscript and/or +superscript of noad |q| to the list that starts at |new_hlist(q)|, +given that the subscript and superscript aren't both empty. The superscript +will appear to the right of the subscript by a given distance |delta|. + +We set |shift_down| and |shift_up| to the minimum amounts to shift the +baseline of subscripts and superscripts based on the given nucleus. + +@<Declare math...@>= +static void make_scripts(pointer @!q, scaled @!delta) +{@+pointer p, @!x, @!y, @!z; /*temporary registers for box construction*/ +scaled @!shift_up, @!shift_down, @!clr; /*dimensions in the calculation*/ +small_number @!t; /*subsidiary size code*/ +p=new_hlist(q); +if (is_char_node(p)) + {@+shift_up=0;shift_down=0; + } +else{@+z=hpack(p, natural); + if (cur_style < script_style) t=script_size;@+else t=script_script_size; + shift_up=height(z)-sup_drop(t); + shift_down=depth(z)+sub_drop(t); + list_ptr(z)=null;flush_node_list(z); + } +if (math_type(supscr(q))==empty) + @<Construct a subscript box |x| when there is no superscript@>@; +else{@+@<Construct a superscript box |x|@>; + if (math_type(subscr(q))==empty) shift_amount(x)=-shift_up; + else@<Construct a sub/superscript combination box |x|, with the superscript offset +by |delta|@>; + } +if (new_hlist(q)==null) new_hlist(q)=x; +else{@+p=new_hlist(q); + while (link(p)!=null) p=link(p); + link(p)=x; + } +} + +@ When there is a subscript without a superscript, the top of the subscript +should not exceed the baseline plus four-fifths of the x-height. + +@<Construct a subscript box |x| when there is no superscript@>= +{@+x=clean_box(subscr(q), sub_style(cur_style)); +width(x)=width(x)+script_space; +if (shift_down < sub1(cur_size)) shift_down=sub1(cur_size); +clr=height(x)-(abs(math_x_height(cur_size)*4)/5); +if (shift_down < clr) shift_down=clr; +shift_amount(x)=shift_down; +} + +@ The bottom of a superscript should never descend below the baseline plus +one-fourth of the x-height. + +@<Construct a superscript box |x|@>= +{@+x=clean_box(supscr(q), sup_style(cur_style)); +width(x)=width(x)+script_space; +if (odd(cur_style)) clr=sup3(cur_size); +else if (cur_style < text_style) clr=sup1(cur_size); +else clr=sup2(cur_size); +if (shift_up < clr) shift_up=clr; +clr=depth(x)+(abs(math_x_height(cur_size))/4); +if (shift_up < clr) shift_up=clr; +} + +@ When both subscript and superscript are present, the subscript must be +separated from the superscript by at least four times |default_rule_thickness|. +If this condition would be violated, the subscript moves down, after which +both subscript and superscript move up so that the bottom of the superscript +is at least as high as the baseline plus four-fifths of the x-height. + +@<Construct a sub/superscript combination box |x|...@>= +{@+y=clean_box(subscr(q), sub_style(cur_style)); +width(y)=width(y)+script_space; +if (shift_down < sub2(cur_size)) shift_down=sub2(cur_size); +clr=4*default_rule_thickness- + ((shift_up-depth(x))-(height(y)-shift_down)); +if (clr > 0) + {@+shift_down=shift_down+clr; + clr=(abs(math_x_height(cur_size)*4)/5)-(shift_up-depth(x)); + if (clr > 0) + {@+shift_up=shift_up+clr; + shift_down=shift_down-clr; + } + } +shift_amount(x)=delta; /*superscript is |delta| to the right of the subscript*/ +p=new_kern((shift_up-depth(x))-(height(y)-shift_down));link(x)=p;link(p)=y; +x=vpack(x, natural);shift_amount(x)=shift_down; +} + +@ We have now tied up all the loose ends of the first pass of |mlist_to_hlist|. +The second pass simply goes through and hooks everything together with the +proper glue and penalties. It also handles the |left_noad| and |right_noad| that +might be present, since |max_h| and |max_d| are now known. Variable |p| points +to a node at the current end of the final hlist. + +@<Make a second pass over the mlist,...@>= +p=temp_head;link(p)=null;q=mlist;r_type=0;cur_style=style; +@<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>; +while (q!=null) + {@+@<If node |q| is a style node, change the style and |goto delete_q|; otherwise +if it is not a noad, put it into the hlist, advance |q|, and |goto done|; otherwise +set |s| to the size of noad |q|, set |t| to the associated type (|ord_noad.. inner_noad|), +and set |pen| to the associated penalty@>; + @<Append inter-element spacing based on |r_type| and |t|@>; + @<Append any |new_hlist| entries for |q|, and any appropriate penalties@>; + if (type(q)==right_noad) t=open_noad; + r_type=t; + delete_q: r=q;q=link(q);free_node(r, s); + done: ;} + +@ Just before doing the big |case| switch in the second pass, the program +sets up default values so that most of the branches are short. + +@<If node |q| is a style node, change the style...@>= +t=ord_noad;s=noad_size;pen=inf_penalty; +switch (type(q)) { +case op_noad: case open_noad: case close_noad: case punct_noad: case inner_noad: t=type(q);@+break; +case bin_noad: {@+t=bin_noad;pen=bin_op_penalty; + } @+break; +case rel_noad: {@+t=rel_noad;pen=rel_penalty; + } @+break; +case ord_noad: case vcenter_noad: case over_noad: case under_noad: do_nothing;@+break; +case radical_noad: s=radical_noad_size;@+break; +case accent_noad: s=accent_noad_size;@+break; +case fraction_noad: {@+t=inner_noad;s=fraction_noad_size; + } @+break; +case left_noad: case right_noad: t=make_left_right(q, style, max_d, max_h);@+break; +case style_node: @<Change the current style and |goto delete_q|@>@; +case whatsit_node: case penalty_node: case rule_node: case disc_node: case adjust_node: case ins_node: case mark_node: + case glue_node: case kern_node: @t@>@;@/ + {@+link(p)=q;p=q;q=link(q);link(p)=null;goto done; + } +default:confusion("mlist3"); +@:this can't happen mlist3}{\quad mlist3@> +} + +@ The |make_left_right| function constructs a left or right delimiter of +the required size and returns the value |open_noad| or |close_noad|. The +|right_noad| and |left_noad| will both be based on the original |style|, +so they will have consistent sizes. + +We use the fact that |right_noad-left_noad==close_noad-open_noad|. + +@<Declare math...@>= +static small_number make_left_right(pointer @!q, small_number @!style, + scaled @!max_d, scaled @!max_h) +{@+scaled delta, @!delta1, @!delta2; /*dimensions used in the calculation*/ +cur_style=style;@<Set up the values...@>; +delta2=max_d+axis_height(cur_size); +delta1=max_h+max_d-delta2; +if (delta2 > delta1) delta1=delta2; /*|delta1| is max distance from axis*/ +delta=(delta1/500)*delimiter_factor; +delta2=delta1+delta1-delimiter_shortfall; +if (delta < delta2) delta=delta2; +new_hlist(q)=var_delimiter(delimiter(q), cur_size, delta); +return type(q)-(left_noad-open_noad); /*|open_noad| or |close_noad|*/ +} + +@ @<Change the current style and |goto delete_q|@>= +{@+cur_style=subtype(q);s=style_node_size; +@<Set up the values of |cur_size| and |cur_mu|, based on |cur_style|@>; +goto delete_q; +} + +@ The inter-element spacing in math formulas depends on a $8\times8$ table that +\TeX\ preloads as a 64-digit string. The elements of this string have the +following significance: +$$\vbox{\halign{#\hfil\cr +\.0 means no space;\cr +\.1 means a conditional thin space (\.{\\nonscript\\mskip\\thinmuskip});\cr +\.2 means a thin space (\.{\\mskip\\thinmuskip});\cr +\.3 means a conditional medium space + (\.{\\nonscript\\mskip\\medmuskip});\cr +\.4 means a conditional thick space + (\.{\\nonscript\\mskip\\thickmuskip});\cr +\.* means an impossible case.\cr}}$$ +This is all pretty cryptic, but {\sl The \TeX book\/} explains what is +supposed to happen, and the string makes it happen. +@:TeXbook}{\sl The \TeX book@> + +A global variable |magic_offset| is computed so that if |a| and |b| are +in the range |ord_noad dotdot inner_noad|, then |str_pool[a*8+b+magic_offset]| +is the digit for spacing between noad types |a| and |b|. + +If \PASCAL\ had provided a good way to preload constant arrays, this part of +the program would not have been so strange. +@:PASCAL}{\PASCAL@> + +@d math_spacing @;@/ +@t\hskip-35pt@> +"0234000122*4000133**3**344*0400400*000000234000111*1111112341011" +@t$ \hskip-35pt$@> + +@ @<Glob...@>= +static const int @!magic_offset=-9*ord_noad; /*used to find inter-element spacing*/ + +@ @<Append inter-element spacing based on |r_type| and |t|@>= +if (r_type > 0) /*not the first noad*/ + {@+switch (so(math_spacing[r_type*8+t+magic_offset])) { + case '0': x=0;@+break; + case '1': if (cur_style < script_style) x=thin_mu_skip_code;@+else x=0;@+break; + case '2': x=thin_mu_skip_code;@+break; + case '3': if (cur_style < script_style) x=med_mu_skip_code;@+else x=0;@+break; + case '4': if (cur_style < script_style) x=thick_mu_skip_code;@+else x=0;@+break; + default:confusion("mlist4"); +@:this can't happen mlist4}{\quad mlist4@> + } + if (x!=0) + {@+y=math_glue(glue_par(x), cur_mu); + z=new_glue(y);glue_ref_count(y)=null;link(p)=z;p=z;@/ + subtype(z)=x+1; /*store a symbolic subtype*/ + } + } + +@ We insert a penalty node after the hlist entries of noad |q| if |pen| +is not an ``infinite'' penalty, and if the node immediately following |q| +is not a penalty node or a |rel_noad| or absent entirely. + +@<Append any |new_hlist| entries for |q|, and any appropriate penalties@>= +if (new_hlist(q)!=null) + {@+link(p)=new_hlist(q); + @/do@+{p=link(p); + }@+ while (!(link(p)==null)); + } +if (penalties) if (link(q)!=null) if (pen < inf_penalty) + {@+r_type=type(link(q)); + if (r_type!=penalty_node) if (r_type!=rel_noad) + {@+z=new_penalty(pen);link(p)=z;p=z; + } + } + +@* Alignment. +It's sort of a miracle whenever \.{\\halign} and \.{\\valign} work, because +they cut across so many of the control structures of \TeX. + +Therefore the +present page is probably not the best place for a beginner to start reading +this program; it is better to master everything else first. + +Let us focus our thoughts on an example of what the input might be, in order +to get some idea about how the alignment miracle happens. The example doesn't +do anything useful, but it is sufficiently general to indicate all of the +special cases that must be dealt with; please do not be disturbed by its +apparent complexity and meaninglessness. +$$\vbox{\halign{\.{#}\hfil\cr +{}\\tabskip 2pt plus 3pt\cr +{}\\halign to 300pt\{u1\#v1\&\cr +\hskip 50pt\\tabskip 1pt plus 1fil u2\#v2\&\cr +\hskip 50pt u3\#v3\\cr\cr +\hskip 25pt a1\&\\omit a2\&\\vrule\\cr\cr +\hskip 25pt \\noalign\{\\vskip 3pt\}\cr +\hskip 25pt b1\\span b2\\cr\cr +\hskip 25pt \\omit\&c2\\span\\omit\\cr\}\cr}}$$ +Here's what happens: + +\yskip +(0) When `\.{\\halign to 300pt\{}' is scanned, the |scan_spec| routine +places the 300pt dimension onto the |save_stack|, and an |align_group| +code is placed above it. This will make it possible to complete the alignment +when the matching `\.\}' is found. + +(1) The preamble is scanned next. Macros in the preamble are not expanded, +@^preamble@> +except as part of a tabskip specification. For example, if \.{u2} had been +a macro in the preamble above, it would have been expanded, since \TeX\ +must look for `\.{minus...}' as part of the tabskip glue. A ``preamble list'' +is constructed based on the user's preamble; in our case it contains the +following seven items: +$$\vbox{\halign{\.{#}\hfil\qquad&(#)\hfil\cr +{}\\glue 2pt plus 3pt&the tabskip preceding column 1\cr +{}\\alignrecord, width $-\infty$&preamble info for column 1\cr +{}\\glue 2pt plus 3pt&the tabskip between columns 1 and 2\cr +{}\\alignrecord, width $-\infty$&preamble info for column 2\cr +{}\\glue 1pt plus 1fil&the tabskip between columns 2 and 3\cr +{}\\alignrecord, width $-\infty$&preamble info for column 3\cr +{}\\glue 1pt plus 1fil&the tabskip following column 3\cr}}$$ +These ``alignrecord'' entries have the same size as an |unset_node|, +since they will later be converted into such nodes. However, at the +moment they have no |type| or |subtype| fields; they have |info| fields +instead, and these |info| fields are initially set to the value |end_span|, +for reasons explained below. Furthermore, the alignrecord nodes have no +|height| or |depth| fields; these are renamed |u_part| and |v_part|, +and they point to token lists for the templates of the alignment. +For example, the |u_part| field in the first alignrecord points to the +token list `\.{u1}', i.e., the template preceding the `\.\#' for column~1. + +(2) \TeX\ now looks at what follows the \.{\\cr} that ended the preamble. +It is not `\.{\\noalign}' or `\.{\\omit}', so this input is put back to +be read again, and the template `\.{u1}' is fed to the scanner. Just +before reading `\.{u1}', \TeX\ goes into restricted horizontal mode. +Just after reading `\.{u1}', \TeX\ will see `\.{a1}', and then (when the +{\.\&} is sensed) \TeX\ will see `\.{v1}'. Then \TeX\ scans an |endv| +token, indicating the end of a column. At this point an |unset_node| is +created, containing the contents of the current hlist (i.e., `\.{u1a1v1}'). +The natural width of this unset node replaces the |width| field of the +alignrecord for column~1; in general, the alignrecords will record the +maximum natural width that has occurred so far in a given column. + +(3) Since `\.{\\omit}' follows the `\.\&', the templates for column~2 +are now bypassed. Again \TeX\ goes into restricted horizontal mode and +makes an |unset_node| from the resulting hlist; but this time the +hlist contains simply `\.{a2}'. The natural width of the new unset box +is remembered in the |width| field of the alignrecord for column~2. + +(4) A third |unset_node| is created for column 3, using essentially the +mechanism that worked for column~1; this unset box contains `\.{u3\\vrule +v3}'. The vertical rule in this case has running dimensions that will later +extend to the height and depth of the whole first row, since each |unset_node| +in a row will eventually inherit the height and depth of its enclosing box. + +(5) The first row has now ended; it is made into a single unset box +comprising the following seven items: +$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr +{}\\glue 2pt plus 3pt\cr +{}\\unsetbox for 1 column: u1a1v1\cr +{}\\glue 2pt plus 3pt\cr +{}\\unsetbox for 1 column: a2\cr +{}\\glue 1pt plus 1fil\cr +{}\\unsetbox for 1 column: u3\\vrule v3\cr +{}\\glue 1pt plus 1fil\cr}}$$ +The width of this unset row is unimportant, but it has the correct height +and depth, so the correct baselineskip glue will be computed as the row +is inserted into a vertical list. + +(6) Since `\.{\\noalign}' follows the current \.{\\cr}, \TeX\ appends +additional material (in this case \.{\\vskip 3pt}) to the vertical list. +While processing this material, \TeX\ will be in internal vertical +mode, and |no_align_group| will be on |save_stack|. + +(7) The next row produces an unset box that looks like this: +$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr +{}\\glue 2pt plus 3pt\cr +{}\\unsetbox for 2 columns: u1b1v1u2b2v2\cr +{}\\glue 1pt plus 1fil\cr +{}\\unsetbox for 1 column: {\rm(empty)}\cr +{}\\glue 1pt plus 1fil\cr}}$$ +The natural width of the unset box that spans columns 1~and~2 is stored +in a ``span node,'' which we will explain later; the |info| field of the +alignrecord for column~1 now points to the new span node, and the |info| +of the span node points to |end_span|. + +(8) The final row produces the unset box +$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr +{}\\glue 2pt plus 3pt\cr +{}\\unsetbox for 1 column: {\rm(empty)}\cr +{}\\glue 2pt plus 3pt\cr +{}\\unsetbox for 2 columns: u2c2v2\cr +{}\\glue 1pt plus 1fil\cr}}$$ +A new span node is attached to the alignrecord for column 2. + +(9) The last step is to compute the true column widths and to change all the +unset boxes to hboxes, appending the whole works to the vertical list that +encloses the \.{\\halign}. The rules for deciding on the final widths of +each unset column box will be explained below. + +\yskip\noindent +Note that as \.{\\halign} is being processed, we fearlessly give up control +to the rest of \TeX. At critical junctures, an alignment routine is +called upon to step in and do some little action, but most of the time +these routines just lurk in the background. It's something like +post-hypnotic suggestion. + +@ We have mentioned that alignrecords contain no |height| or |depth| fields. +Their |glue_sign| and |glue_order| are pre-empted as well, since it +is necessary to store information about what to do when a template ends. +This information is called the |extra_info| field. + +@d u_part(A) mem[A+height_offset].i /*pointer to \<u_j> token list*/ +@d v_part(A) mem[A+depth_offset].i /*pointer to \<v_j> token list*/ +@d extra_info(A) info(A+list_offset) /*info to remember during template*/ + +@ Alignments can occur within alignments, so a small stack is used to access +the alignrecord information. At each level we have a |preamble| pointer, +indicating the beginning of the preamble list; a |cur_align| pointer, +indicating the current position in the preamble list; a |cur_span| pointer, +indicating the value of |cur_align| at the beginning of a sequence of +spanned columns; a |cur_loop| pointer, indicating the tabskip glue before +an alignrecord that should be copied next if the current list is extended; +and the |align_state| variable, which indicates the nesting of braces so +that \.{\\cr} and \.{\\span} and tab marks are properly intercepted. +There also are pointers |cur_head| and |cur_tail| to the head and tail +of a list of adjustments being moved out from horizontal mode to +vertical~mode. + +The current values of these seven quantities appear in global variables; +when they have to be pushed down, they are stored in 5-word nodes, and +|align_ptr| points to the topmost such node. + +@d preamble link(align_head) /*the current preamble list*/ +@d align_stack_node_size 5 /*number of |mem| words to save alignment states*/ + +@<Glob...@>= +static pointer @!cur_align; /*current position in preamble list*/ +static pointer @!cur_span; /*start of currently spanned columns in preamble list*/ +static pointer @!cur_loop; /*place to copy when extending a periodic preamble*/ +static pointer @!align_ptr; /*most recently pushed-down alignment stack node*/ +static pointer @!cur_head, @!cur_tail; /*adjustment list pointers*/ + +@ The |align_state| and |preamble| variables are initialized elsewhere. + +@<Set init...@>= +align_ptr=null;cur_align=null;cur_span=null;cur_loop=null; +cur_head=null;cur_tail=null; + +@ Alignment stack maintenance is handled by a pair of trivial routines +called |push_alignment| and |pop_alignment|. + +@p static void push_alignment(void) +{@+pointer p; /*the new alignment stack node*/ +p=get_node(align_stack_node_size); +link(p)=align_ptr;info(p)=cur_align; +llink(p)=preamble;rlink(p)=cur_span; +mem[p+2].i=cur_loop;mem[p+3].i=align_state; +info(p+4)=cur_head;link(p+4)=cur_tail; +align_ptr=p; +cur_head=get_avail(); +} +@# +static void pop_alignment(void) +{@+pointer p; /*the top alignment stack node*/ +free_avail(cur_head); +p=align_ptr; +cur_tail=link(p+4);cur_head=info(p+4); +align_state=mem[p+3].i;cur_loop=mem[p+2].i; +cur_span=rlink(p);preamble=llink(p); +cur_align=info(p);align_ptr=link(p); +free_node(p, align_stack_node_size); +} + +@ \TeX\ has eight procedures that govern alignments: |init_align| and +|fin_align| are used at the very beginning and the very end; |init_row| and +|fin_row| are used at the beginning and end of individual rows; |init_span| +is used at the beginning of a sequence of spanned columns (possibly involving +only one column); |init_col| and |fin_col| are used at the beginning and +end of individual columns; and |align_peek| is used after \.{\\cr} to see +whether the next item is \.{\\noalign}. + +We shall consider these routines in the order they are first used during +the course of a complete \.{\\halign}, namely |init_align|, |align_peek|, +|init_row|, |init_span|, |init_col|, |fin_col|, |fin_row|, |fin_align|. + +@ When \.{\\halign} or \.{\\valign} has been scanned in an appropriate +mode, \TeX\ calls |init_align|, whose task is to get everything off to a +good start. This mostly involves scanning the preamble and putting its +information into the preamble list. +@^preamble@> + +@p @t\4@>@<Declare the procedure called |get_preamble_token|@>@t@>@/ +static void align_peek(void);@/ +void normal_paragraph(void);@/ +static void init_align(void) +{@+ +pointer save_cs_ptr; /*|warning_index| value for error messages*/ +pointer @!p; /*for short-term temporary use*/ +save_cs_ptr=cur_cs; /*\.{\\halign} or \.{\\valign}, usually*/ +push_alignment();align_state=-1000000; /*enter a new alignment level*/ +@<Check for improper alignment in displayed math@>; +push_nest(); /*enter a new semantic level*/ +@<Change current mode to |-vmode| for \.{\\halign}, |-hmode| for \.{\\valign}@>; +scan_spec(align_group, false);@/ +@<Scan the preamble and record it in the |preamble| list@>; +new_save_level(align_group); +if (every_cr!=null) begin_token_list(every_cr, every_cr_text); +align_peek(); /*look for \.{\\noalign} or \.{\\omit}*/ +} + +@ In vertical modes, |prev_depth| already has the correct value. But +if we are in |mmode| (displayed formula mode), we reach out to the +enclosing vertical mode for the |prev_depth| value that produces the +correct baseline calculations. + +@<Change current mode...@>= +if (mode==mmode) + {@+mode=-vmode;prev_depth=nest[nest_ptr-2].aux_field.sc; + } +else if (mode > 0) negate(mode) + +@ When \.{\\halign} is used as a displayed formula, there should be +no other pieces of mlists present. + +@<Check for improper alignment in displayed math@>= +if ((mode==mmode)&&((tail!=head)||(incompleat_noad!=null))) + {@+print_err("Improper ");print_esc("halign");print(" inside $$'s"); +@.Improper \\halign...@> + help3("Displays can use special alignments (like \\eqalignno)",@/ + "only if nothing but the alignment itself is between $$'s.",@/ + "So I've deleted the formulas that preceded this alignment."); + error();flush_math(); + } + +@ @<Scan the preamble and record it in the |preamble| list@>= +preamble=null;cur_align=align_head;cur_loop=null;scanner_status=aligning; +warning_index=save_cs_ptr;align_state=-1000000; + /*at this point, |cur_cmd==left_brace|*/ +loop@+{@+@<Append the current tabskip glue to the preamble list@>; + if (cur_cmd==car_ret) goto done; /*\.{\\cr} ends the preamble*/ + @<Scan preamble text until |cur_cmd| is |tab_mark| or |car_ret|, looking for changes +in the tabskip glue; append an alignrecord to the preamble list@>; + } +done: scanner_status=normal + +@ @<Append the current tabskip glue to the preamble list@>= +link(cur_align)=new_param_glue(tab_skip_code); +cur_align=link(cur_align) + +@ @<Scan preamble text until |cur_cmd| is |tab_mark| or |car_ret|...@>= +@<Scan the template \<u_j>, putting the resulting token list in |hold_head|@>; +link(cur_align)=new_null_box();cur_align=link(cur_align); /*a new alignrecord*/ +info(cur_align)=end_span;width(cur_align)=null_flag; +u_part(cur_align)=link(hold_head); +@<Scan the template \<v_j>, putting the resulting token list in |hold_head|@>; +v_part(cur_align)=link(hold_head) + +@ We enter `\.{\\span}' into |eqtb| with |tab_mark| as its command code, +and with |span_code| as the command modifier. This makes \TeX\ interpret it +essentially the same as an alignment delimiter like `\.\&', yet it is +recognizably different when we need to distinguish it from a normal delimiter. +It also turns out to be useful to give a special |cr_code| to `\.{\\cr}', +and an even larger |cr_cr_code| to `\.{\\crcr}'. + +The end of a template is represented by two ``frozen'' control sequences +called \.{\\endtemplate}. The first has the command code |end_template|, which +is | > outer_call|, so it will not easily disappear in the presence of errors. +The |get_x_token| routine converts the first into the second, which has |endv| +as its command code. + +@d span_code 256 /*distinct from any character*/ +@d cr_code 257 /*distinct from |span_code| and from any character*/ +@d cr_cr_code (cr_code+1) /*this distinguishes \.{\\crcr} from \.{\\cr}*/ +@d end_template_token cs_token_flag+frozen_end_template + +@<Put each of \TeX's primitives into the hash table@>= +primitive("span", tab_mark, span_code);@/ +@!@:span\_}{\.{\\span} primitive@> +primitive("cr", car_ret, cr_code); +@!@:cr\_}{\.{\\cr} primitive@> +text(frozen_cr)=text(cur_val);eqtb[frozen_cr]=eqtb[cur_val];@/ +primitive("crcr", car_ret, cr_cr_code); +@!@:cr\_cr\_}{\.{\\crcr} primitive@> +text(frozen_end_template)=text(frozen_endv)=s_no("endtemplate"); +eq_type(frozen_endv)=endv;equiv(frozen_endv)=null_list; +eq_level(frozen_endv)=level_one;@/ +eqtb[frozen_end_template]=eqtb[frozen_endv]; +eq_type(frozen_end_template)=end_template; + +@ @<Cases of |print_cmd_chr|...@>= +case tab_mark: if (chr_code==span_code) print_esc("span"); + else chr_cmd("alignment tab character ")@;@+break; +case car_ret: if (chr_code==cr_code) print_esc("cr"); + else print_esc("crcr");@+break; + +@ The preamble is copied directly, except that \.{\\tabskip} causes a change +to the tabskip glue, thereby possibly expanding macros that immediately +follow it. An appearance of \.{\\span} also causes such an expansion. + +Note that if the preamble contains `\.{\\global\\tabskip}', the `\.{\\global}' +token survives in the preamble and the `\.{\\tabskip}' defines new +tabskip glue (locally). + +@<Declare the procedure called |get_preamble_token|@>= +static void get_preamble_token(void) +{@+ +restart: get_token(); +while ((cur_chr==span_code)&&(cur_cmd==tab_mark)) + {@+get_token(); /*this token will be expanded once*/ + if (cur_cmd > max_command) + {@+expand();get_token(); + } + } +if (cur_cmd==endv) + fatal_error("(interwoven alignment preambles are not allowed)"); +@.interwoven alignment preambles...@> +if ((cur_cmd==assign_glue)&&(cur_chr==glue_base+tab_skip_code)) + {@+scan_optional_equals();scan_glue(glue_val); + if (global_defs > 0) geq_define(glue_base+tab_skip_code, glue_ref, cur_val); + else eq_define(glue_base+tab_skip_code, glue_ref, cur_val); + goto restart; + } +} + +@ Spaces are eliminated from the beginning of a template. + +@<Scan the template \<u_j>...@>= +p=hold_head;link(p)=null; +loop@+{@+get_preamble_token(); + if (cur_cmd==mac_param) goto done1; + if ((cur_cmd <= car_ret)&&(cur_cmd >= tab_mark)&&(align_state==-1000000)) + if ((p==hold_head)&&(cur_loop==null)&&(cur_cmd==tab_mark) + ) cur_loop=cur_align; + else{@+print_err("Missing # inserted in alignment preamble"); +@.Missing \# inserted...@> + help3("There should be exactly one # between &'s, when an",@/ + "\\halign or \\valign is being set up. In this case you had",@/ + "none, so I've put one in; maybe that will work."); + back_error();goto done1; + } + else if ((cur_cmd!=spacer)||(p!=hold_head)) + {@+link(p)=get_avail();p=link(p);info(p)=cur_tok; + } + } +done1: + +@ @<Scan the template \<v_j>...@>= +p=hold_head;link(p)=null; +loop@+{@+resume: get_preamble_token(); + if ((cur_cmd <= car_ret)&&(cur_cmd >= tab_mark)&&(align_state==-1000000)) + goto done2; + if (cur_cmd==mac_param) + {@+print_err("Only one # is allowed per tab"); +@.Only one \# is allowed...@> + help3("There should be exactly one # between &'s, when an",@/ + "\\halign or \\valign is being set up. In this case you had",@/ + "more than one, so I'm ignoring all but the first."); + error();goto resume; + } + link(p)=get_avail();p=link(p);info(p)=cur_tok; + } +done2: link(p)=get_avail();p=link(p); +info(p)=end_template_token /*put \.{\\endtemplate} at the end*/ + +@ The tricky part about alignments is getting the templates into the +scanner at the right time, and recovering control when a row or column +is finished. + +We usually begin a row after each \.{\\cr} has been sensed, unless that +\.{\\cr} is followed by \.{\\noalign} or by the right brace that terminates +the alignment. The |align_peek| routine is used to look ahead and do +the right thing; it either gets a new row started, or gets a \.{\\noalign} +started, or finishes off the alignment. + +@<Declare the procedure called |align_peek|@>= +static void align_peek(void) +{@+ +restart: align_state=1000000; +@/do@+{get_x_or_protected(); +}@+ while (!(cur_cmd!=spacer)); +if (cur_cmd==no_align) + {@+scan_left_brace();new_save_level(no_align_group); + if (mode==-vmode) normal_paragraph(); + } +else if (cur_cmd==right_brace) fin_align(); +else if ((cur_cmd==car_ret)&&(cur_chr==cr_cr_code)) + goto restart; /*ignore \.{\\crcr}*/ +else{@+init_row(); /*start a new row*/ + init_col(); /*start a new column and replace what we peeked at*/ + } +} + +@ To start a row (i.e., a `row' that rhymes with `dough' but not with `bough'), +we enter a new semantic level, copy the first tabskip glue, and change +from internal vertical mode to restricted horizontal mode or vice versa. +The |space_factor| and |prev_depth| are not used on this semantic level, +but we clear them to zero just to be tidy. + +@p @t\4@>@<Declare the procedure called |init_span|@>@t@>@/ +static void init_row(void) +{@+push_nest();mode=(-hmode-vmode)-mode; +if (mode==-hmode) space_factor=0;@+else prev_depth=0; +tail_append(new_glue(glue_ptr(preamble))); +subtype(tail)=tab_skip_code+1;@/ +cur_align=link(preamble);cur_tail=cur_head;init_span(cur_align); +} + +@ The parameter to |init_span| is a pointer to the alignrecord where the +next column or group of columns will begin. A new semantic level is +entered, so that the columns will generate a list for subsequent packaging. + +@<Declare the procedure called |init_span|@>= +static void init_span(pointer @!p) +{@+push_nest(); +if (mode==-hmode) space_factor=1000; +else{@+prev_depth=ignore_depth;normal_paragraph(); + } +cur_span=p; +} + +@ When a column begins, we assume that |cur_cmd| is either |omit| or else +the current token should be put back into the input until the \<u_j> +template has been scanned. (Note that |cur_cmd| might be |tab_mark| or +|car_ret|.) We also assume that |align_state| is approximately 1000000 at +this time. We remain in the same mode, and start the template if it is +called for. + +@p static void init_col(void) +{@+extra_info(cur_align)=cur_cmd; +if (cur_cmd==omit) align_state=0; +else{@+back_input();begin_token_list(u_part(cur_align), u_template); + } /*now |align_state==1000000|*/ +} + +@ The scanner sets |align_state| to zero when the \<u_j> template ends. When +a subsequent \.{\\cr} or \.{\\span} or tab mark occurs with |align_state==0|, +the scanner activates the following code, which fires up the \<v_j> template. +We need to remember the |cur_chr|, which is either |cr_cr_code|, |cr_code|, +|span_code|, or a character code, depending on how the column text has ended. + +This part of the program had better not be activated when the preamble +to another alignment is being scanned, or when no alignment preamble is active. + +@<Insert the \(v)\<v_j>...@>= +{@+if ((scanner_status==aligning)||(cur_align==null)) + fatal_error("(interwoven alignment preambles are not allowed)"); +@.interwoven alignment preambles...@> +cur_cmd=extra_info(cur_align);extra_info(cur_align)=cur_chr; +if (cur_cmd==omit) begin_token_list(omit_template, v_template); +else begin_token_list(v_part(cur_align), v_template); +align_state=1000000;goto restart; +} + +@ The token list |omit_template| just referred to is a constant token +list that contains the special control sequence \.{\\endtemplate} only. + +@<Initialize the special...@>= +info(omit_template)=end_template_token; /*|link(omit_template)==null|*/ + +@ When the |endv| command at the end of a \<v_j> template comes through the +scanner, things really start to happen; and it is the |fin_col| routine +that makes them happen. This routine returns |true| if a row as well as a +column has been finished. + +@p static bool fin_col(void) +{@+ +pointer p; /*the alignrecord after the current one*/ +pointer @!q, @!r; /*temporary pointers for list manipulation*/ +pointer @!s; /*a new span node*/ +pointer @!u; /*a new unset box*/ +scaled @!w; /*natural width*/ +glue_ord @!o; /*order of infinity*/ +halfword @!n; /*span counter*/ +if (cur_align==null) confusion("endv"); +q=link(cur_align);@+if (q==null) confusion("endv"); +@:this can't happen endv}{\quad endv@> +if (align_state < 500000) + fatal_error("(interwoven alignment preambles are not allowed)"); +@.interwoven alignment preambles...@> +p=link(q); +@<If the preamble list has been traversed, check that the row has ended@>; +if (extra_info(cur_align)!=span_code) + {@+unsave();new_save_level(align_group);@/ + @<Package an unset box for the current column and record its width@>; + @<Copy the tabskip glue between columns@>; + if (extra_info(cur_align) >= cr_code) + {@+return true; + } + init_span(p); + } +align_state=1000000; +@/do@+{get_x_or_protected(); +}@+ while (!(cur_cmd!=spacer)); +cur_align=p; +init_col();return false; +} + +@ @<If the preamble list has been traversed, check that the row has ended@>= +if ((p==null)&&(extra_info(cur_align) < cr_code)) + if (cur_loop!=null) @<Lengthen the preamble periodically@>@; + else{@+print_err("Extra alignment tab has been changed to "); +@.Extra alignment tab...@> + print_esc("cr"); + help3("You have given more \\span or & marks than there were",@/ + "in the preamble to the \\halign or \\valign now in progress.",@/ + "So I'll assume that you meant to type \\cr instead."); + extra_info(cur_align)=cr_code;error(); + } + +@ @<Lengthen the preamble...@>= +{@+link(q)=new_null_box();p=link(q); /*a new alignrecord*/ +info(p)=end_span;width(p)=null_flag;cur_loop=link(cur_loop); +@<Copy the templates from node |cur_loop| into node |p|@>; +cur_loop=link(cur_loop); +link(p)=new_glue(glue_ptr(cur_loop)); +} + +@ @<Copy the templates from node |cur_loop| into node |p|@>= +q=hold_head;r=u_part(cur_loop); +while (r!=null) + {@+link(q)=get_avail();q=link(q);info(q)=info(r);r=link(r); + } +link(q)=null;u_part(p)=link(hold_head); +q=hold_head;r=v_part(cur_loop); +while (r!=null) + {@+link(q)=get_avail();q=link(q);info(q)=info(r);r=link(r); + } +link(q)=null;v_part(p)=link(hold_head) + +@ @<Copy the tabskip glue...@>= +tail_append(new_glue(glue_ptr(link(cur_align)))); +subtype(tail)=tab_skip_code+1 + +@ @<Package an unset...@>= +{@+if (mode==-hmode) + {@+adjust_tail=cur_tail;u=hpack(link(head), natural); + if (type(u)==hlist_node) w=width(u); + else w=max_dimen+1; + cur_tail=adjust_tail;adjust_tail=null; + } +else{@+u=vpackage(link(head), natural, 0); + if (type(u)==vlist_node) w=height(u); + else w=max_dimen+1; + } +n=min_quarterword; /*this represents a span count of 1*/ +if (cur_span!=cur_align) @<Update width entry for spanned columns@>@; +else if (w > width(cur_align)) width(cur_align)=w; +if (type(u)==whatsit_node) +{ if (subtype(u)==hset_node ||subtype(u)==vset_node) type(u)=unset_set_node; + else type(u)=unset_pack_node; + span_count(u)=n; +} +else if (type(u)==hlist_node ||type(u)==vlist_node) +{ type(u)=unset_node;span_count(u)=n; +@<Determine the stretch order@>; +glue_order(u)=o;glue_stretch(u)=total_stretch[o];@/ +@<Determine the shrink order@>; +glue_sign(u)=o;glue_shrink(u)=total_shrink[o];@/ +} +pop_nest();link(tail)=u;tail=u; +} + +@ A span node is a 2-word record containing |width|, |info|, and |link| +fields. The |link| field is not really a link, it indicates the number of +spanned columns; the |info| field points to a span node for the same +starting column, having a greater extent of spanning, or to |end_span|, +which has the largest possible |link| field; the |width| field holds the +largest natural width corresponding to a particular set of spanned columns. + +A list of the maximum widths so far, for spanned columns starting at a +given column, begins with the |info| field of the alignrecord for that +column. + +@d span_node_size 2 /*number of |mem| words for a span node*/ + +@<Initialize the special list heads...@>= +link(end_span)=max_quarterword+1;info(end_span)=null; + +@ @<Update width entry for spanned columns@>= +{@+q=cur_span; +@/do@+{incr(n);q=link(link(q)); +}@+ while (!(q==cur_align)); +if (n > max_quarterword) confusion("256 spans"); /*this can happen, but won't*/ +@^system dependencies@> +@:this can't happen 256 spans}{\quad 256 spans@> +q=cur_span;while (link(info(q)) < n) q=info(q); +if (link(info(q)) > n) + {@+s=get_node(span_node_size);info(s)=info(q);link(s)=n; + info(q)=s;width(s)=w; + } +else if (width(info(q)) < w) width(info(q))=w; +} + +@ At the end of a row, we append an unset box to the current vlist (for +\.{\\halign}) or the current hlist (for \.{\\valign}). This unset box +contains the unset boxes for the columns, separated by the tabskip glue. +Everything will be set later. + +@p static void fin_row(void) +{@+pointer p; /*the new unset box*/ +if (mode==-hmode) + {@+p=hpack(link(head), natural); + pop_nest();append_to_vlist(p); + if (cur_head!=cur_tail) + {@+link(tail)=link(cur_head);tail=cur_tail; + } + } +else{@+p=vpack(link(head), natural);pop_nest(); + link(tail)=p;tail=p;space_factor=1000; + } +type(p)=unset_node;glue_stretch(p)=0; +if (every_cr!=null) begin_token_list(every_cr, every_cr_text); +align_peek(); +} /*note that |glue_shrink(p)==0| since |glue_shrink====shift_amount|*/ + +@ Finally, we will reach the end of the alignment, and we can breathe a +sigh of relief that memory hasn't overflowed. All the unset boxes will now be +set so that the columns line up, taking due account of spanned columns. + +@p static void do_assignments(void);@/ +static void resume_after_display(void);@/ +extern void build_page(void); +static void fin_align(void) +{@+pointer @!p, @!q, @!r, @!s, @!u, @!v; /*registers for the list operations*/ +scaled @!t, @!w; /*width of column*/ +bool x=false; /* indicates an extende alignment */ +scaled @!o; /*shift offset for unset boxes*/ +halfword @!n; /*matching span amount*/ +scaled @!rule_save; /*temporary storage for |overfull_rule|*/ +memory_word @!aux_save; /*temporary storage for |aux|*/ +if (cur_group!=align_group) confusion("align1"); +@:this can't happen align}{\quad align@> +unsave(); /*that |align_group| was for individual entries*/ +if (cur_group!=align_group) confusion("align0"); +unsave(); /*that |align_group| was for the whole alignment*/ +if (nest[nest_ptr-1].mode_field==mmode) o=display_indent; + else o=0; +@<Go through the preamble list, determining the column widths and changing the alignrecords +to dummy unset boxes@>; +if (x) +{ @<Handle an alignment that depends on |hsize| or |vsize|@>@; + pop_alignment(); +} +else +{ @<Package the preamble list, to determine the actual tabskip glue amounts, and let + |p| point to this prototype box@>; + @<Set the glue in all the unset boxes of the current list@>; + flush_node_list(p);pop_alignment(); +} +@<Insert the \(c)current list into its environment@>; +} @/ +@t\4@>@<Declare the procedure called |align_peek|@>@; +@ @<Handle an alignment that depends on |hsize| or |vsize|@>= + pointer r=get_node(align_node_size); + save_ptr=save_ptr-2;pack_begin_line=-mode_line; + + type(r)=whatsit_node; subtype(r)=align_node; + align_preamble(r)=preamble; + align_list(r)=link(head); + align_extent(r)=new_xdimen(saved(1),saved_hfactor(1),saved_vfactor(1)); + align_m(r)= saved(0); + align_v(r)= (mode!=-vmode); + link(head)=r; tail=r; + pack_begin_line=0; + +@ It's time now to dismantle the preamble list and to compute the column +widths. Let $w_{ij}$ be the maximum of the natural widths of all entries +that span columns $i$ through $j$, inclusive. The alignrecord for column~$i$ +contains $w_{ii}$ in its |width| field, and there is also a linked list of +the nonzero $w_{ij}$ for increasing $j$, accessible via the |info| field; +these span nodes contain the value $j-i+|min_quarterword|$ in their +|link| fields. The values of $w_{ii}$ were initialized to |null_flag|, which +we regard as $-\infty$. + +The final column widths are defined by the formula +$$w_j=\max_{1\le i\le j}\biggl( w_{ij}-\sum_{i\le k<j}(t_k+w_k)\biggr),$$ +where $t_k$ is the natural width of the tabskip glue between columns +$k$ and~$k+1$. However, if $w_{ij}=-\infty$ for all |i| in the range +|1 <= i <= j| (i.e., if every entry that involved column~|j| also involved +column~|j+1|), we let $w_j=0$, and we zero out the tabskip glue after +column~|j|. + +\TeX\ computes these values by using the following scheme: First $w_1=w_{11}$. +Then replace $w_{2j}$ by $\max(w_{2j},w_{1j}-t_1-w_1)$, for all $j>1$. +Then $w_2=w_{22}$. Then replace $w_{3j}$ by $\max(w_{3j},w_{2j}-t_2-w_2)$ +for all $j>2$; and so on. If any $w_j$ turns out to be $-\infty$, its +value is changed to zero and so is the next tabskip. + +@<Go through the preamble list,...@>= +q=link(preamble); +@/do@+{flush_list(u_part(q));flush_list(v_part(q)); +p=link(link(q)); +if (width(q)==null_flag) + @<Nullify |width(q)| and the tabskip glue following this column@>; +if (info(q)!=end_span) + @<Merge the widths in the span nodes of |q| with those of |p|, destroying the span +nodes of |q|@>; +type(q)=unset_node;span_count(q)=min_quarterword;height(q)=0; +depth(q)=0;glue_order(q)=normal;glue_sign(q)=normal; +glue_stretch(q)=0;glue_shrink(q)=0;q=p; + if (width(q)>max_dimen) x=true; +}@+ while (!(q==null)) + +@ @<Nullify |width(q)| and the tabskip glue following this column@>= +{@+width(q)=0;r=link(q);s=glue_ptr(r); +if (s!=zero_glue) + {@+add_glue_ref(zero_glue);delete_glue_ref(s); + glue_ptr(r)=zero_glue; + } +} + +@ Merging of two span-node lists is a typical exercise in the manipulation of +linearly linked data structures. The essential invariant in the following +|@/do@+{| loop is that we want to dispense with node |r|, in |q|'s list, +and |u| is its successor; all nodes of |p|'s list up to and including |s| +have been processed, and the successor of |s| matches |r| or precedes |r| +or follows |r|, according as |link(r)==n| or |link(r) > n| or |link(r) < n|. + +@<Merge the widths...@>= +{@+t=width(q)+width(glue_ptr(link(q))); +r=info(q);s=end_span;info(s)=p;n=min_quarterword+1; +@/do@+{width(r)=width(r)-t;u=info(r); +while (link(r) > n) + {@+s=info(s);n=link(info(s))+1; + } +if (link(r) < n) + {@+info(r)=info(s);info(s)=r;decr(link(r));s=r; + } +else{@+if (width(r) > width(info(s))) width(info(s))=width(r); + free_node(r, span_node_size); + } +r=u; +}@+ while (!(r==end_span)); +} + +@ Now the preamble list has been converted to a list of alternating unset +boxes and tabskip glue, where the box widths are equal to the final +column sizes. In case of \.{\\valign}, we change the widths to heights, +so that a correct error message will be produced if the alignment is +overfull or underfull. + +@<Package the preamble list...@>= +save_ptr=save_ptr-2;pack_begin_line=-mode_line; +if (mode==-vmode) + {@+rule_save=overfull_rule; + overfull_rule=0; /*prevent rule from being packaged*/ + p=hpack(preamble, saved(1), saved_hfactor(1), saved_vfactor(1), saved(0));overfull_rule=rule_save; + } +else{@+q=link(preamble); + @/do@+{height(q)=width(q);width(q)=0;q=link(link(q)); + }@+ while (!(q==null)); + p=vpack(preamble, saved(1), saved_hfactor(1), saved_vfactor(1), saved(0)); + q=link(preamble); + @/do@+{width(q)=height(q);height(q)=0;q=link(link(q)); + }@+ while (!(q==null)); + } +pack_begin_line=0 + +@ @<Set the glue in all the unset...@>= +q=link(head);s=head; +while (q!=null) + {@+if (!is_char_node(q)) + if (type(q)==unset_node) + @<Set the unset box |q| and the unset boxes in it@>@; + else if (type(q)==rule_node) + @<Make the running dimensions in rule |q| extend to the boundaries of the alignment@>; + s=q;q=link(q); + } + +@ @<Make the running dimensions in rule |q| extend...@>= +{@+if (is_running(width(q))) width(q)=width(p); +if (is_running(height(q))) height(q)=height(p); +if (is_running(depth(q))) depth(q)=depth(p); +if (o!=0) + {@+r=link(q);link(q)=null;q=hpack(q, natural); + shift_amount(q)=o;link(q)=r;link(s)=q; + } +} + +@ The unset box |q| represents a row that contains one or more unset boxes, +depending on how soon \.{\\cr} occurred in that row. + +@<Set the unset box |q| and the unset boxes in it@>= +{@+if (mode==-vmode) + {@+type(q)=hlist_node;width(q)=width(p); + } +else{@+type(q)=vlist_node;height(q)=height(p); + } +glue_order(q)=glue_order(p);glue_sign(q)=glue_sign(p); +glue_set(q)=glue_set(p);shift_amount(q)=o; +r=link(list_ptr(q));s=link(list_ptr(p)); +@/do@+{@<Set the glue in node |r| and change it from an unset node@>; +r=link(link(r));s=link(link(s)); +}@+ while (!(r==null)); +} + +@ A box made from spanned columns will be followed by tabskip glue nodes and +by empty boxes as if there were no spanning. This permits perfect alignment +of subsequent entries, and it prevents values that depend on floating point +arithmetic from entering into the dimensions of any boxes. + +@<Set the glue in node |r|...@>= +n=span_count(r);t=width(s);w=t;u=hold_head; +while (n > min_quarterword) + {@+decr(n); + @<Append tabskip glue and an empty box to list |u|, and update |s| and |t| as the +prototype nodes are passed@>; + } +if (mode==-vmode) + @<Make the unset node |r| into an |hlist_node| of width |w|, setting the glue as +if the width were |t|@>@; +else@<Make the unset node |r| into a |vlist_node| of height |w|, setting the glue +as if the height were |t|@>; +shift_amount(r)=0; +if (u!=hold_head) /*append blank boxes to account for spanned nodes*/ + {@+link(u)=link(r);link(r)=link(hold_head);r=u; + } + +@ @<Append tabskip glue and an empty box to list |u|...@>= +s=link(s);v=glue_ptr(s);link(u)=new_glue(v);u=link(u); +subtype(u)=tab_skip_code+1;t=t+width(v); +if (glue_sign(p)==stretching) + {@+if (stretch_order(v)==glue_order(p)) + t=t+round(float(glue_set(p))*stretch(v)); +@^real multiplication@> + } +else if (glue_sign(p)==shrinking) + {@+if (shrink_order(v)==glue_order(p)) + t=t-round(float(glue_set(p))*shrink(v)); + } +s=link(s);link(u)=new_null_box();u=link(u);t=t+width(s); +if (mode==-vmode) width(u)=width(s);@+else + {@+type(u)=vlist_node;height(u)=width(s); + } + +@ @<Make the unset node |r| into an |hlist_node| of width |w|...@>= +{@+height(r)=height(q);depth(r)=depth(q); +if (t==width(r)) + {@+glue_sign(r)=normal;glue_order(r)=normal; + set_glue_ratio_zero(glue_set(r)); + } +else if (t > width(r)) + {@+glue_sign(r)=stretching; + if (glue_stretch(r)==0) set_glue_ratio_zero(glue_set(r)); + else glue_set(r)=unfloat((t-width(r))/(double)glue_stretch(r)); +@^real division@> + } +else{@+glue_order(r)=glue_sign(r);glue_sign(r)=shrinking; + if (glue_shrink(r)==0) set_glue_ratio_zero(glue_set(r)); + else if ((glue_order(r)==normal)&&(width(r)-t > glue_shrink(r))) + set_glue_ratio_one(glue_set(r)); + else glue_set(r)=unfloat((width(r)-t)/(double)glue_shrink(r)); + } +width(r)=w;type(r)=hlist_node; +} + +@ @<Make the unset node |r| into a |vlist_node| of height |w|...@>= +{@+width(r)=width(q); +if (t==height(r)) + {@+glue_sign(r)=normal;glue_order(r)=normal; + set_glue_ratio_zero(glue_set(r)); + } +else if (t > height(r)) + {@+glue_sign(r)=stretching; + if (glue_stretch(r)==0) set_glue_ratio_zero(glue_set(r)); + else glue_set(r)=unfloat((t-height(r))/(double)glue_stretch(r)); +@^real division@> + } +else{@+glue_order(r)=glue_sign(r);glue_sign(r)=shrinking; + if (glue_shrink(r)==0) set_glue_ratio_zero(glue_set(r)); + else if ((glue_order(r)==normal)&&(height(r)-t > glue_shrink(r))) + set_glue_ratio_one(glue_set(r)); + else glue_set(r)=unfloat((height(r)-t)/(double)glue_shrink(r)); + } +height(r)=w;type(r)=vlist_node; +} + +@ We now have a completed alignment, in the list that starts at |head| +and ends at |tail|. This list will be merged with the one that encloses +it. (In case the enclosing mode is |mmode|, for displayed formulas, +we will need to insert glue before and after the display; that part of the +program will be deferred until we're more familiar with such operations.) + +In restricted horizontal mode, the |clang| part of |aux| is undefined; +an over-cautious \PASCAL\ runtime system may complain about this. +@^dirty \PASCAL@> + +@<Insert the \(c)current list into its environment@>= +aux_save=aux;p=link(head);q=tail;pop_nest(); +if (mode==mmode) @<Finish an alignment in a display@>@; +else{@+aux=aux_save;link(tail)=p; + if (p!=null) tail=q; + if (mode==vmode) build_page(); + } + +@* Breaking paragraphs into lines. +We come now to what is probably the most interesting algorithm of \TeX: +the mechanism for choosing the ``best possible'' breakpoints that yield +the individual lines of a paragraph. \TeX's line-breaking algorithm takes +a given horizontal list and converts it to a sequence of boxes that are +appended to the current vertical list. In the course of doing this, it +creates a special data structure containing three kinds of records that are +not used elsewhere in \TeX. Such nodes are created while a paragraph is +being processed, and they are destroyed afterwards; thus, the other parts +of \TeX\ do not need to know anything about how line-breaking is done. + +The method used here is based on an approach devised by Michael F. Plass and +@^Plass, Michael Frederick@> +@^Knuth, Donald Ervin@> +the author in 1977, subsequently generalized and improved by the same two +people in 1980. A detailed discussion appears in {\sl SOFTWARE---Practice +\AM\ Experience \bf11} (1981), 1119--1184, where it is shown that the +line-breaking problem can be regarded as a special case of the problem of +computing the shortest path in an acyclic network. The cited paper includes +numerous examples and describes the history of line breaking as it has been +practiced by printers through the ages. The present implementation adds two +new ideas to the algorithm of 1980: Memory space requirements are considerably +reduced by using smaller records for inactive nodes than for active ones, +and arithmetic overflow is avoided by using ``delta distances'' instead of +keeping track of the total distance from the beginning of the paragraph to the +current point. + +@ The |line_break| procedure should be invoked only in horizontal mode; it +leaves that mode and places its output into the current vlist of the +enclosing vertical mode (or internal vertical mode). +There is one explicit parameter: |final_widow_penalty| is the amount of +additional penalty to be inserted before the final line of the paragraph. + +There are also a number of implicit parameters: The hlist to be broken +starts at |link(head)|, and it is nonempty. The value of |prev_graf| in the +enclosing semantic level tells where the paragraph should begin in the +sequence of line numbers, in case hanging indentation or \.{\\parshape} +is in use; |prev_graf| is zero unless this paragraph is being continued +after a displayed formula. Other implicit parameters, such as the +|par_shape_ptr| and various penalties to use for hyphenation, etc., appear +in |eqtb|. + +After |line_break| has acted, it will have updated the current vlist and the +value of |prev_graf|. Furthermore, the global variable |just_box| will +point to the final box created by |line_break|, so that the width of this +line can be ascertained when it is necessary to decide whether to use +|above_display_skip| or |above_display_short_skip| before a displayed formula. + +@<Glob...@>= +static pointer @!just_box; /*the |hlist_node| for the last line of the new paragraph*/ + +@ Since |line_break| is a rather lengthy procedure---sort of a small world unto +itself---we must build it up little by little, somewhat more cautiously +than we have done with the simpler procedures of \TeX. Here is the +general outline. + +@p @t\4@>@<Declare subprocedures for |line_break|@>@; +void line_break(int @!final_widow_penalty) +{@+ +@<Local variables for line breaking@>@; +pack_begin_line=mode_line; /*this is for over/underfull box messages*/ +@<Get ready to start line breaking@>; +@<Find optimal breakpoints@>; +@<Break the paragraph at the chosen breakpoints, justify the resulting lines to the +correct widths, and append them to the current vertical list@>; +@<Clean up the memory by removing the break nodes@>; +pack_begin_line=0; +} +@# +@t\4@>@<Declare \eTeX\ procedures for use by |main_control|@>@; + +@ The first task is to move the list from |head| to |temp_head| and go +into the enclosing semantic level. We also append the \.{\\parfillskip} +glue to the end of the paragraph, removing a space (or other glue node) if +it was there, since spaces usually precede blank lines and instances of +`\.{\$\$}'. The |par_fill_skip| is preceded by an infinite penalty, so +it will never be considered as a potential breakpoint. + +This code assumes that a |glue_node| and a |penalty_node| occupy the +same number of |mem|~words. +@^data structure assumptions@> + +@<Get ready to start...@>= +link(temp_head)=link(head); +if (is_char_node(tail)) tail_append(new_penalty(inf_penalty))@; +else if (type(tail)!=glue_node) tail_append(new_penalty(inf_penalty))@; +else{@+type(tail)=penalty_node;delete_glue_ref(glue_ptr(tail)); + flush_node_list(leader_ptr(tail));penalty(tail)=inf_penalty; + } +link(tail)=new_param_glue(par_fill_skip_code); +init_cur_lang=prev_graf%0200000; +init_l_hyf=prev_graf/020000000; +init_r_hyf=(prev_graf/0200000)%0100; +pop_nest(); + +@ When looking for optimal line breaks, \TeX\ creates a ``break node'' for +each break that is {\sl feasible}, in the sense that there is a way to end +a line at the given place without requiring any line to stretch more than +a given tolerance. A break node is characterized by three things: the position +of the break (which is a pointer to a |glue_node|, |math_node|, |penalty_node|, +or |disc_node|); the ordinal number of the line that will follow this +breakpoint; and the fitness classification of the line that has just +ended, i.e., |tight_fit|, |decent_fit|, |loose_fit|, or |very_loose_fit|. + +@d tight_fit 3 /*fitness classification for lines shrinking 0.5 to 1.0 of their + shrinkability*/ +@d loose_fit 1 /*fitness classification for lines stretching 0.5 to 1.0 of their + stretchability*/ +@d very_loose_fit 0 /*fitness classification for lines stretching more than + their stretchability*/ +@d decent_fit 2 /*fitness classification for all other lines*/ + +@ The algorithm essentially determines the best possible way to achieve +each feasible combination of position, line, and fitness. Thus, it answers +questions like, ``What is the best way to break the opening part of the +paragraph so that the fourth line is a tight line ending at such-and-such +a place?'' However, the fact that all lines are to be the same length +after a certain point makes it possible to regard all sufficiently large +line numbers as equivalent, when the looseness parameter is zero, and this +makes it possible for the algorithm to save space and time. + +An ``active node'' and a ``passive node'' are created in |mem| for each +feasible breakpoint that needs to be considered. Active nodes are three +words long and passive nodes are two words long. We need active nodes only +for breakpoints near the place in the paragraph that is currently being +examined, so they are recycled within a comparatively short time after +they are created. + +@ An active node for a given breakpoint contains six fields: + +\yskip\hang|link| points to the next node in the list of active nodes; the +last active node has |link==last_active|. + +\yskip\hang|break_node| points to the passive node associated with this +breakpoint. + +\yskip\hang|line_number| is the number of the line that follows this +breakpoint. + +\yskip\hang|fitness| is the fitness classification of the line ending at this +breakpoint. + +\yskip\hang|type| is either |hyphenated| or |unhyphenated|, depending on +whether this breakpoint is a |disc_node|. + +\yskip\hang|total_demerits| is the minimum possible sum of demerits over all +lines leading from the beginning of the paragraph to this breakpoint. + +\yskip\noindent +The value of |link(active)| points to the first active node on a linked list +of all currently active nodes. This list is in order by |line_number|, +except that nodes with |line_number > easy_line| may be in any order relative +to each other. + +@d active_node_size 3 /*number of words in active nodes*/ +@d fitness(A) subtype(A) /*|very_loose_fit dotdot tight_fit| on final line for this break*/ +@d break_node(A) rlink(A) /*pointer to the corresponding passive node*/ +@d line_number(A) llink(A) /*line that begins at this breakpoint*/ +@d total_demerits(A) mem[A+2].i /*the quantity that \TeX\ minimizes*/ +@d unhyphenated 0 /*the |type| of a normal active break node*/ +@d hyphenated 1 /*the |type| of an active node that breaks at a |disc_node|*/ +@d last_active active /*the active list ends where it begins*/ + +@ @<Initialize the special list heads...@>= +type(last_active)=hyphenated;line_number(last_active)=max_halfword; +subtype(last_active)=0; /*the |subtype| is never examined by the algorithm*/ + +@ The passive node for a given breakpoint contains only four fields: + +\yskip\hang|link| points to the passive node created just before this one, +if any, otherwise it is |null|. + +\yskip\hang|cur_break| points to the position of this breakpoint in the +horizontal list for the paragraph being broken. + +\yskip\hang|prev_break| points to the passive node that should precede this +one in an optimal path to this breakpoint. + +\yskip\hang|serial| is equal to |n| if this passive node is the |n|th +one created during the current pass. (This field is used only when +printing out detailed statistics about the line-breaking calculations.) + +\yskip\noindent +There is a global variable called |passive| that points to the most +recently created passive node. Another global variable, |printed_node|, +is used to help print out the paragraph when detailed information about +the line-breaking computation is being displayed. + +@d passive_node_size 2 /*number of words in passive nodes*/ +@d cur_break(A) rlink(A) /*in passive node, points to position of this breakpoint*/ +@d prev_break(A) llink(A) /*points to passive node that should precede this one*/ +@d serial(A) info(A) /*serial number for symbolic identification*/ + +@<Glob...@>= +static pointer @!passive; /*most recent node on passive list*/ +static pointer @!printed_node; /*most recent node that has been printed*/ +static halfword @!pass_number; /*the number of passive nodes allocated on this pass*/ + +@ The active list also contains ``delta'' nodes that help the algorithm +compute the badness of individual lines. Such nodes appear only between two +active nodes, and they have |type==delta_node|. If |p| and |r| are active nodes +and if |q| is a delta node between them, so that |link(p)==q| and |link(q)==r|, +then |q| tells the space difference between lines in the horizontal list that +start after breakpoint |p| and lines that start after breakpoint |r|. In +other words, if we know the length of the line that starts after |p| and +ends at our current position, then the corresponding length of the line that +starts after |r| is obtained by adding the amounts in node~|q|. A delta node +contains six scaled numbers, since it must record the net change in glue +stretchability with respect to all orders of infinity. The natural width +difference appears in |mem[q+1].sc|; the stretch differences in units of +pt, fil, fill, and filll appear in |mem[q+2 dotdot q+5].sc|; and the shrink difference +appears in |mem[q+6].sc|. The |subtype| field of a delta node is not used. + +@d delta_node_size 7 /*number of words in a delta node*/ +@d delta_node 2 /*|type| field in a delta node*/ + +@ As the algorithm runs, it maintains a set of six delta-like registers +for the length of the line following the first active breakpoint to the +current position in the given hlist. When it makes a pass through the +active list, it also maintains a similar set of six registers for the +length following the active breakpoint of current interest. A third set +holds the length of an empty line (namely, the sum of \.{\\leftskip} and +\.{\\rightskip}); and a fourth set is used to create new delta nodes. + +When we pass a delta node we want to do operations like +$$\hbox{\ignorespaces|for +k=1 to 6 do cur_active_width[k]=cur_active_width[k]+mem[q+k].sc|};$$ and we +want to do this without the overhead of |for| loops. The |do_all_six| +macro makes such six-tuples convenient. + +@d do_all_six(A) A(1);A(2);A(3);A(4);A(5);A(6) + +@<Glob...@>= +static scaled @!active_width0[6], *const @!active_width = @!active_width0-1; + /*distance from first active node to~|cur_p|*/ +static scaled @!cur_active_width0[6], *const @!cur_active_width = @!cur_active_width0-1; /*distance from current active node*/ +static scaled @!background0[6], *const @!background = @!background0-1; /*length of an ``empty'' line*/ +static scaled @!break_width0[6], *const @!break_width = @!break_width0-1; /*length being computed after current break*/ + +@ Let's state the principles of the delta nodes more precisely and concisely, +so that the following programs will be less obscure. For each legal +breakpoint~|p| in the paragraph, we define two quantities $\alpha(p)$ and +$\beta(p)$ such that the length of material in a line from breakpoint~|p| +to breakpoint~|q| is $\gamma+\beta(q)-\alpha(p)$, for some fixed $\gamma$. +Intuitively, $\alpha(p)$ and $\beta(q)$ are the total length of material from +the beginning of the paragraph to a point ``after'' a break at |p| and to a +point ``before'' a break at |q|; and $\gamma$ is the width of an empty line, +namely the length contributed by \.{\\leftskip} and \.{\\rightskip}. + +Suppose, for example, that the paragraph consists entirely of alternating +boxes and glue skips; let the boxes have widths $x_1\ldots x_n$ and +let the skips have widths $y_1\ldots y_n$, so that the paragraph can be +represented by $x_1y_1\ldots x_ny_n$. Let $p_i$ be the legal breakpoint +at $y_i$; then $\alpha(p_i)=x_1+y_1+\cdots+x_i+y_i$, and $\beta(p_i)= +x_1+y_1+\cdots+x_i$. To check this, note that the length of material from +$p_2$ to $p_5$, say, is $\gamma+x_3+y_3+x_4+y_4+x_5=\gamma+\beta(p_5) +-\alpha(p_2)$. + +The quantities $\alpha$, $\beta$, $\gamma$ involve glue stretchability and +shrinkability as well as a natural width. If we were to compute $\alpha(p)$ +and $\beta(p)$ for each |p|, we would need multiple precision arithmetic, and +the multiprecise numbers would have to be kept in the active nodes. +\TeX\ avoids this problem by working entirely with relative differences +or ``deltas.'' Suppose, for example, that the active list contains +$a_1\,\delta_1\,a_2\,\delta_2\,a_3$, where the |a|'s are active breakpoints +and the $\delta$'s are delta nodes. Then $\delta_1=\alpha(a_1)-\alpha(a_2)$ +and $\delta_2=\alpha(a_2)-\alpha(a_3)$. If the line breaking algorithm is +currently positioned at some other breakpoint |p|, the |active_width| array +contains the value $\gamma+\beta(p)-\alpha(a_1)$. If we are scanning through +the list of active nodes and considering a tentative line that runs from +$a_2$ to~|p|, say, the |cur_active_width| array will contain the value +$\gamma+\beta(p)-\alpha(a_2)$. Thus, when we move from $a_2$ to $a_3$, +we want to add $\alpha(a_2)-\alpha(a_3)$ to |cur_active_width|; and this +is just $\delta_2$, which appears in the active list between $a_2$ and +$a_3$. The |background| array contains $\gamma$. The |break_width| array +will be used to calculate values of new delta nodes when the active +list is being updated. + +@ Glue nodes in a horizontal list that is being paragraphed are not supposed to +include ``infinite'' shrinkability; that is why the algorithm maintains +four registers for stretching but only one for shrinking. If the user tries to +introduce infinite shrinkability, the shrinkability will be reset to finite +and an error message will be issued. A boolean variable |no_shrink_error_yet| +prevents this error message from appearing more than once per paragraph. + +@d check_shrinkage(A) if ((shrink_order(A)!=normal)&&(shrink(A)!=0)) + {@+A=finite_shrink(A); + } + +@<Glob...@>= +static bool @!no_shrink_error_yet; /*have we complained about infinite shrinkage?*/ + +@ @<Declare subprocedures for |line_break|@>= +static pointer finite_shrink(pointer @!p) /*recovers from infinite shrinkage*/ +{@+pointer q; /*new glue specification*/ +if (no_shrink_error_yet) + {@+no_shrink_error_yet=false; + print_err("Infinite glue shrinkage found in a paragraph"); +@.Infinite glue shrinkage...@> + help5("The paragraph just ended includes some glue that has",@/ + "infinite shrinkability, e.g., `\\hskip 0pt minus 1fil'.",@/ + "Such glue doesn't belong there---it allows a paragraph",@/ + "of any length to fit on one line. But it's safe to proceed,",@/ + "since the offensive shrinkability has been made finite."); + error(); + } +q=new_spec(p);shrink_order(q)=normal; +delete_glue_ref(p);return q; +} + +@ @<Get ready to start...@>= +no_shrink_error_yet=true;@/ +check_shrinkage(left_skip);check_shrinkage(right_skip);@/ +q=left_skip;r=right_skip;background[1]=width(q)+width(r);@/ +background[2]=0;background[3]=0;background[4]=0;background[5]=0;@/ +background[2+stretch_order(q)]=stretch(q);@/ +background[2+stretch_order(r)]=@|background[2+stretch_order(r)]+stretch(r);@/ +background[6]=shrink(q)+shrink(r); + +@ A pointer variable |cur_p| runs through the given horizontal list as we look +for breakpoints. This variable is global, since it is used both by |line_break| +and by its subprocedure |try_break|. + +Another global variable called |threshold| is used to determine the feasibility +of individual lines: Breakpoints are feasible if there is a way to reach +them without creating lines whose badness exceeds |threshold|. (The +badness is compared to |threshold| before penalties are added, so that +penalty values do not affect the feasibility of breakpoints, except that +no break is allowed when the penalty is 10000 or more.) If |threshold| +is 10000 or more, all legal breaks are considered feasible, since the +|badness| function specified above never returns a value greater than~10000. + +Up to three passes might be made through the paragraph in an attempt to find at +least one set of feasible breakpoints. On the first pass, we have +|threshold==pretolerance| and |second_pass==final_pass==false|. +If this pass fails to find a +feasible solution, |threshold| is set to |tolerance|, |second_pass| is set +|true|, and an attempt is made to hyphenate as many words as possible. +If that fails too, we add |emergency_stretch| to the background +stretchability and set |final_pass==true|. + +@<Glob...@>= +pointer @!cur_p; /*the current breakpoint under consideration*/ +static bool @!second_pass; /*is this our second attempt to break this paragraph?*/ +static bool @!final_pass; /*is this our final attempt to break this paragraph?*/ +static int @!threshold; /*maximum badness on feasible lines*/ + +@ The heart of the line-breaking procedure is `|try_break|', a subroutine +that tests if the current breakpoint |cur_p| is feasible, by running +through the active list to see what lines of text can be made from active +nodes to~|cur_p|. If feasible breaks are possible, new break nodes are +created. If |cur_p| is too far from an active node, that node is +deactivated. + +The parameter |pi| to |try_break| is the penalty associated +with a break at |cur_p|; we have |pi==eject_penalty| if the break is forced, +and |pi==inf_penalty| if the break is illegal. + +The other parameter, |break_type|, is set to |hyphenated| or |unhyphenated|, +depending on whether or not the current break is at a |disc_node|. The +end of a paragraph is also regarded as `|hyphenated|'; this case is +distinguishable by the condition |cur_p==null|. + +@d copy_to_cur_active(A) cur_active_width[A]=active_width[A] +@<Declare subprocedures for |line_break|@>= +static void try_break(int @!pi, small_number @!break_type) +{@+ +pointer r; /*runs through the active list*/ +pointer @!prev_r; /*stays a step behind |r|*/ +halfword @!old_l; /*maximum line number in current equivalence class of lines*/ +bool @!no_break_yet; /*have we found a feasible break at |cur_p|?*/ +@<Other local variables for |try_break|@>@; +@<Make sure that |pi| is in the proper range@>; +no_break_yet=true;prev_r=active;old_l=0; +do_all_six(copy_to_cur_active); +loop@+{@+resume: r=link(prev_r); + @<If node |r| is of type |delta_node|, update |cur_active_width|, set |prev_r| and +|prev_prev_r|, then |goto continue|@>; + @<If a line number class has ended, create new active nodes for the best feasible +breaks in that class; then |return| if |r=last_active|, otherwise compute the new +|line_width|@>; + @<Consider the demerits for a line from |r| to |cur_p|; deactivate node |r| if it +should no longer be active; then |goto continue| if a line from |r| to |cur_p| is +infeasible, otherwise record a new feasible break@>; + } +end: ; +#ifdef @!STAT +@<Update the value of |printed_node| for symbolic displays@>; +#endif +@; +} + +@ @<Other local variables for |try_break|@>= +pointer @!prev_prev_r; /*a step behind |prev_r|, if |type(prev_r)==delta_node|*/ +pointer @!s; /*runs through nodes ahead of |cur_p|*/ +pointer @!q; /*points to a new node being created*/ +pointer @!v; /*points to a glue specification or a node ahead of |cur_p|*/ +int @!t; /*node count, if |cur_p| is a discretionary node*/ +internal_font_number @!f; /*used in character width calculation*/ +halfword @!l; /*line number of current active node*/ +bool @!node_r_stays_active; /*should node |r| remain in the active list?*/ +scaled @!line_width; /*the current line will be justified to this width*/ +int @!fit_class; /*possible fitness class of test line*/ +halfword @!b; /*badness of test line*/ +int @!d; /*demerits of test line*/ +bool @!artificial_demerits; /*has |d| been forced to zero?*/ +#ifdef @!STAT +pointer @!save_link; /*temporarily holds value of |link(cur_p)|*/ +#endif +scaled @!shortfall; /*used in badness calculations*/ + +@ @<Make sure that |pi| is in the proper range@>= +if (abs(pi) >= inf_penalty) + if (pi > 0) goto end; /*this breakpoint is inhibited by infinite penalty*/ + else pi=eject_penalty /*this breakpoint will be forced*/ + +@ The following code uses the fact that |type(last_active)!=delta_node|. + +@d update_width(A) @| + cur_active_width[A]=cur_active_width[A]+mem[r+A].sc + +@<If node |r|...@>= +@^inner loop@> +if (type(r)==delta_node) + {@+do_all_six(update_width); + prev_prev_r=prev_r;prev_r=r;goto resume; + } + +@ As we consider various ways to end a line at |cur_p|, in a given line number +class, we keep track of the best total demerits known, in an array with +one entry for each of the fitness classifications. For example, +|minimal_demerits[tight_fit]| contains the fewest total demerits of feasible +line breaks ending at |cur_p| with a |tight_fit| line; |best_place[tight_fit]| +points to the passive node for the break before~|cur_p| that achieves such +an optimum; and |best_pl_line[tight_fit]| is the |line_number| field in the +active node corresponding to |best_place[tight_fit]|. When no feasible break +sequence is known, the |minimal_demerits| entries will be equal to +|awful_bad|, which is $2^{30}-1$. Another variable, |minimum_demerits|, +keeps track of the smallest value in the |minimal_demerits| array. + +@d awful_bad 07777777777 /*more than a billion demerits*/ + +@<Global...@>= +static int @!minimal_demerits0[tight_fit-very_loose_fit+1], *const @!minimal_demerits = @!minimal_demerits0-very_loose_fit; /*best total + demerits known for current line class and position, given the fitness*/ +static int @!minimum_demerits; /*best total demerits known for current line class + and position*/ +static pointer @!best_place0[tight_fit-very_loose_fit+1], *const @!best_place = @!best_place0-very_loose_fit; /*how to achieve + |minimal_demerits|*/ +static halfword @!best_pl_line0[tight_fit-very_loose_fit+1], *const @!best_pl_line = @!best_pl_line0-very_loose_fit; /*corresponding + line number*/ + +@ @<Get ready to start...@>= +minimum_demerits=awful_bad; +minimal_demerits[tight_fit]=awful_bad; +minimal_demerits[decent_fit]=awful_bad; +minimal_demerits[loose_fit]=awful_bad; +minimal_demerits[very_loose_fit]=awful_bad; + +@ The first part of the following code is part of \TeX's inner loop, so +we don't want to waste any time. The current active node, namely node |r|, +contains the line number that will be considered next. At the end of the +list we have arranged the data structure so that |r==last_active| and +|line_number(last_active) > old_l|. +@^inner loop@> + +@<If a line number class...@>= +{@+l=line_number(r); +if (l > old_l) + {@+ /*now we are no longer in the inner loop*/ + if ((minimum_demerits < awful_bad)&&@| + ((old_l!=easy_line)||(r==last_active))) + @<Create new active nodes for the best feasible breaks just found@>; + if (r==last_active) goto end; + @<Compute the new line width@>; + } +} + +@ It is not necessary to create new active nodes having |minimal_demerits| +greater than +|minimum_demerits+abs(adj_demerits)|, since such active nodes will never +be chosen in the final paragraph breaks. This observation allows us to +omit a substantial number of feasible breakpoints from further consideration. + +@<Create new active nodes...@>= +{@+if (no_break_yet) @<Compute the values of |break_width|@>; +@<Insert a delta node to prepare for breaks at |cur_p|@>; +if (abs(adj_demerits) >= awful_bad-minimum_demerits) + minimum_demerits=awful_bad-1; +else minimum_demerits=minimum_demerits+abs(adj_demerits); +for (fit_class=very_loose_fit; fit_class<=tight_fit; fit_class++) + {@+if (minimal_demerits[fit_class] <= minimum_demerits) + @<Insert a new active node from |best_place[fit_class]| to |cur_p|@>; + minimal_demerits[fit_class]=awful_bad; + } +minimum_demerits=awful_bad; +@<Insert a delta node to prepare for the next active node@>; +} + +@ When we insert a new active node for a break at |cur_p|, suppose this +new node is to be placed just before active node |a|; then we essentially +want to insert `$\delta\,|cur_p|\,\delta^\prime$' before |a|, where +$\delta=\alpha(a)-\alpha(|cur_p|)$ and $\delta^\prime=\alpha(|cur_p|)-\alpha(a)$ +in the notation explained above. The |cur_active_width| array now holds +$\gamma+\beta(|cur_p|)-\alpha(a)$; so $\delta$ can be obtained by +subtracting |cur_active_width| from the quantity $\gamma+\beta(|cur_p|)- +\alpha(|cur_p|)$. The latter quantity can be regarded as the length of a +line ``from |cur_p| to |cur_p|''; we call it the |break_width| at |cur_p|. + +The |break_width| is usually negative, since it consists of the background +(which is normally zero) minus the width of nodes following~|cur_p| that are +eliminated after a break. If, for example, node |cur_p| is a glue node, the +width of this glue is subtracted from the background; and we also look +ahead to eliminate all subsequent glue and penalty and kern and math +nodes, subtracting their widths as well. + +Kern nodes do not disappear at a line break unless they are |explicit|. + +@d set_break_width_to_background(A) break_width[A]=background[A] + +@<Compute the values of |break...@>= +{@+no_break_yet=false;do_all_six(set_break_width_to_background); +s=cur_p; +if (break_type > unhyphenated) if (cur_p!=null) + @<Compute the discretionary |break_width| values@>; +while (s!=null) + {@+if (is_char_node(s)) goto done; + switch (type(s)) { + case glue_node: @<Subtract glue from |break_width|@>@;@+break; + case penalty_node: do_nothing;@+break; + case math_node: break_width[1]=break_width[1]-width(s);@+break; + case kern_node: if (subtype(s)!=explicit) goto done; + else break_width[1]=break_width[1]-width(s);@+break; + default:goto done; + } @/ + s=link(s); + } +done: ;} + +@ @<Subtract glue from |break...@>= +{@+v=glue_ptr(s);break_width[1]=break_width[1]-width(v); +break_width[2+stretch_order(v)]=break_width[2+stretch_order(v)]-stretch(v); +break_width[6]=break_width[6]-shrink(v); +} + +@ When |cur_p| is a discretionary break, the length of a line ``from |cur_p| to +|cur_p|'' has to be defined properly so that the other calculations work out. +Suppose that the pre-break text at |cur_p| has length $l_0$, the post-break +text has length $l_1$, and the replacement text has length |l|. Suppose +also that |q| is the node following the replacement text. Then length of a +line from |cur_p| to |q| will be computed as $\gamma+\beta(q)-\alpha(|cur_p|)$, +where $\beta(q)=\beta(|cur_p|)-l_0+l$. The actual length will be the background +plus $l_1$, so the length from |cur_p| to |cur_p| should be $\gamma+l_0+l_1-l$. +If the post-break text of the discretionary is empty, a break may also +discard~|q|; in that unusual case we subtract the length of~|q| and any +other nodes that will be discarded after the discretionary break. + +The value of $l_0$ need not be computed, since |line_break| will put +it into the global variable |disc_width| before calling |try_break|. + +@<Glob...@>= +static scaled @!disc_width; /*the length of discretionary material preceding a break*/ + +@ @<Compute the discretionary |break...@>= +{@+t=replace_count(cur_p);v=cur_p;s=post_break(cur_p); +while (t > 0) + {@+decr(t);v=link(v); + @<Subtract the width of node |v| from |break_width|@>; + } +while (s!=null) + {@+@<Add the width of node |s| to |break_width|@>; + s=link(s); + } +break_width[1]=break_width[1]+disc_width; +if (post_break(cur_p)==null) s=link(v); + /*nodes may be discardable after the break*/ +} + +@ Replacement texts and discretionary texts are supposed to contain +only character nodes, kern nodes, ligature nodes, and box or rule nodes. + +@<Subtract the width of node |v|...@>= +if (is_char_node(v)) + {@+f=font(v); + break_width[1]=break_width[1]-char_width(f, char_info(f, character(v))); + } +else switch (type(v)) { + case ligature_node: {@+f=font(lig_char(v));@/ + break_width[1]=@|break_width[1]- + char_width(f, char_info(f, character(lig_char(v)))); + } @+break; + case hlist_node: case vlist_node: case rule_node: case kern_node: + break_width[1]=break_width[1]-width(v);@+break; + default:confusion("disc1"); +@:this can't happen disc1}{\quad disc1@> + } + +@ @<Add the width of node |s| to |b...@>= +if (is_char_node(s)) + {@+f=font(s); + break_width[1]=@|break_width[1]+char_width(f, char_info(f, character(s))); + } +else switch (type(s)) { + case ligature_node: {@+f=font(lig_char(s)); + break_width[1]=break_width[1]+ + char_width(f, char_info(f, character(lig_char(s)))); + } @+break; + case hlist_node: case vlist_node: case rule_node: case kern_node: + break_width[1]=break_width[1]+width(s);@+break; + default:confusion("disc2"); +@:this can't happen disc2}{\quad disc2@> + } + +@ We use the fact that |type(active)!=delta_node|. + +@d convert_to_break_width(A) @| + mem[prev_r+A].sc=@|@t\hskip10pt@>mem[prev_r+A].sc + -cur_active_width[A]+break_width[A] +@d store_break_width(A) active_width[A]=break_width[A] +@d new_delta_to_break_width(A) @| + mem[q+A].sc=break_width[A]-cur_active_width[A] + +@<Insert a delta node to prepare for breaks at |cur_p|@>= +if (type(prev_r)==delta_node) /*modify an existing delta node*/ + {@+do_all_six(convert_to_break_width); + } +else if (prev_r==active) /*no delta node needed at the beginning*/ + {@+do_all_six(store_break_width); + } +else{@+q=get_node(delta_node_size);link(q)=r;type(q)=delta_node;@/ + subtype(q)=0; /*the |subtype| is not used*/ + do_all_six(new_delta_to_break_width); + link(prev_r)=q;prev_prev_r=prev_r;prev_r=q; + } + +@ When the following code is performed, we will have just inserted at +least one active node before |r|, so |type(prev_r)!=delta_node|. + +@d new_delta_from_break_width(A) @|mem[q+A].sc= + cur_active_width[A]-break_width[A] + +@<Insert a delta node to prepare for the next active node@>= +if (r!=last_active) + {@+q=get_node(delta_node_size);link(q)=r;type(q)=delta_node;@/ + subtype(q)=0; /*the |subtype| is not used*/ + do_all_six(new_delta_from_break_width); + link(prev_r)=q;prev_prev_r=prev_r;prev_r=q; + } + +@ When we create an active node, we also create the corresponding +passive node. + +@<Insert a new active node from |best_place[fit_class]| to |cur_p|@>= +{@+q=get_node(passive_node_size); +link(q)=passive;passive=q;cur_break(q)=cur_p; +#ifdef @!STAT +incr(pass_number);serial(q)=pass_number; +#endif +@;@/ +prev_break(q)=best_place[fit_class];@/ +q=get_node(active_node_size);break_node(q)=passive; +line_number(q)=best_pl_line[fit_class]+1; +fitness(q)=fit_class;type(q)=break_type; +total_demerits(q)=minimal_demerits[fit_class]; +link(q)=r;link(prev_r)=q;prev_r=q; +#ifdef @!STAT +if (tracing_paragraphs > 0) + @<Print a symbolic description of the new break node@>; +#endif +@;@/ +} + +@ @<Print a symbolic description of the new break node@>= +{@+print_nl("@@@@");print_int(serial(passive)); +@.\AT\AT@> +print(": line ");print_int(line_number(q)-1); +print_char('.');print_int(fit_class); +if (break_type==hyphenated) print_char('-'); +print(" t=");print_int(total_demerits(q)); +print(" -> @@@@"); +if (prev_break(passive)==null) print_char('0'); +else print_int(serial(prev_break(passive))); +} + +@ The length of lines depends on whether the user has specified +\.{\\parshape} or \.{\\hangindent}. If |par_shape_ptr| is not null, it +points to a $(2n+1)$-word record in |mem|, where the |info| in the first +word contains the value of |n|, and the other $2n$ words contain the left +margins and line lengths for the first |n| lines of the paragraph; the +specifications for line |n| apply to all subsequent lines. If +|par_shape_ptr==null|, the shape of the paragraph depends on the value of +|n==hang_after|; if |n >= 0|, hanging indentation takes place on lines |n+1|, +|n+2|, \dots, otherwise it takes place on lines 1, \dots, $\vert +n\vert$. When hanging indentation is active, the left margin is +|hang_indent|, if |hang_indent >= 0|, else it is 0; the line length is +$|hsize|-\vert|hang_indent|\vert$. The normal setting is +|par_shape_ptr==null|, |hang_after==1|, and |hang_indent==0|. +Note that if |hang_indent==0|, the value of |hang_after| is irrelevant. +@^length of lines@> @^hanging indentation@> + +@<Glob...@>= +static halfword @!easy_line; /*line numbers | > easy_line| are equivalent in break nodes*/ +halfword @!last_special_line; /*line numbers | > last_special_line| all have + the same width*/ +static scaled @!first_width; /*the width of all lines | <= last_special_line|, if + no \.{\\parshape} has been specified*/ +scaled @!second_width; /*the width of all lines | > last_special_line|*/ +static scaled @!first_indent; /*left margin to go with |first_width|*/ +scaled @!second_indent; /*left margin to go with |second_width|*/ + +@ We compute the values of |easy_line| and the other local variables relating +to line length when the |line_break| procedure is initializing itself. + +@<Get ready to start...@>= +if (par_shape_ptr==null) + if (hang_indent==0) + {@+last_special_line=0;second_width=hsize; + second_indent=0; + } + else@<Set line length parameters in preparation for hanging indentation@>@; +else{@+last_special_line=info(par_shape_ptr)-1; + second_width=mem[par_shape_ptr+2*(last_special_line+1)].sc; + second_indent=mem[par_shape_ptr+2*last_special_line+1].sc; + } +if (looseness==0) easy_line=last_special_line; +else easy_line=max_halfword + +@ @<Set line length parameters in preparation for hanging indentation@>= +{@+last_special_line=abs(hang_after); +if (hang_after < 0) + {@+first_width=hsize-abs(hang_indent); + if (hang_indent >= 0) first_indent=hang_indent; + else first_indent=0; + second_width=hsize;second_indent=0; + } +else{@+first_width=hsize;first_indent=0; + second_width=hsize-abs(hang_indent); + if (hang_indent >= 0) second_indent=hang_indent; + else second_indent=0; + } +} + +@ When we come to the following code, we have just encountered the first +active node~|r| whose |line_number| field contains |l|. Thus we want to +compute the length of the $l\mskip1mu$th line of the current paragraph. Furthermore, +we want to set |old_l| to the last number in the class of line numbers +equivalent to~|l|. + +@<Compute the new line width@>= +if (l > easy_line) + {@+line_width=second_width;old_l=max_halfword-1; + } +else{@+old_l=l; + if (l > last_special_line) line_width=second_width; + else if (par_shape_ptr==null) line_width=first_width; + else line_width=mem[par_shape_ptr+2*l@,].sc; + } + +@ The remaining part of |try_break| deals with the calculation of +demerits for a break from |r| to |cur_p|. + +The first thing to do is calculate the badness, |b|. This value will always +be between zero and |inf_bad+1|; the latter value occurs only in the +case of lines from |r| to |cur_p| that cannot shrink enough to fit the necessary +width. In such cases, node |r| will be deactivated. +We also deactivate node~|r| when a break at~|cur_p| is forced, since future +breaks must go through a forced break. + +@<Consider the demerits for a line from |r| to |cur_p|...@>= +{@+artificial_demerits=false;@/ +@^inner loop@> +shortfall=line_width-cur_active_width[1]; /*we're this much too short*/ +if (shortfall > 0) + @<Set the value of |b| to the badness for stretching the line, and compute the corresponding +|fit_class|@>@; +else@<Set the value of |b| to the badness for shrinking the line, and compute the +corresponding |fit_class|@>; +if ((b > inf_bad)||(pi==eject_penalty)) + @<Prepare to deactivate node~|r|, and |goto deactivate| unless there is a reason +to consider lines of text from |r| to |cur_p|@>@; +else{@+prev_r=r; + if (b > threshold) goto resume; + node_r_stays_active=true; + } +@<Record a new feasible break@>; +if (node_r_stays_active) goto resume; /*|prev_r| has been set to |r|*/ +deactivate: @<Deactivate node |r|@>; +} + +@ When a line must stretch, the available stretchability can be found in the +subarray |cur_active_width[2 dotdot 5]|, in units of points, fil, fill, and filll. + +The present section is part of \TeX's inner loop, and it is most often performed +when the badness is infinite; therefore it is worth while to make a quick +test for large width excess and small stretchability, before calling the +|badness| subroutine. +@^inner loop@> + +@<Set the value of |b| to the badness for stretching...@>= +if ((cur_active_width[3]!=0)||(cur_active_width[4]!=0)||@| + (cur_active_width[5]!=0)) + {@+b=0;fit_class=decent_fit; /*infinite stretch*/ + } +else{@+if (shortfall > 7230584) if (cur_active_width[2] < 1663497) + {@+b=inf_bad;fit_class=very_loose_fit;goto done1; + } + b=badness(shortfall, cur_active_width[2]); + if (b > 12) + if (b > 99) fit_class=very_loose_fit; + else fit_class=loose_fit; + else fit_class=decent_fit; + done1: ; + } + +@ Shrinkability is never infinite in a paragraph; +we can shrink the line from |r| to |cur_p| by at most |cur_active_width[6]|. + +@<Set the value of |b| to the badness for shrinking...@>= +{@+if (-shortfall > cur_active_width[6]) b=inf_bad+1; +else b=badness(-shortfall, cur_active_width[6]); +if (b > 12) fit_class=tight_fit;@+else fit_class=decent_fit; +} + +@ During the final pass, we dare not lose all active nodes, lest we lose +touch with the line breaks already found. The code shown here makes sure +that such a catastrophe does not happen, by permitting overfull boxes as +a last resort. This particular part of \TeX\ was a source of several subtle +bugs before the correct program logic was finally discovered; readers +who seek to ``improve'' \TeX\ should therefore think thrice before daring +to make any changes here. +@^overfull boxes@> + +@<Prepare to deactivate node~|r|, and |goto deactivate| unless...@>= +{@+if (final_pass&&(minimum_demerits==awful_bad)&&@| + (link(r)==last_active)&& + (prev_r==active)) + artificial_demerits=true; /*set demerits zero, this break is forced*/ +else if (b > threshold) goto deactivate; +node_r_stays_active=false; +} + +@ When we get to this part of the code, the line from |r| to |cur_p| is +feasible, its badness is~|b|, and its fitness classification is |fit_class|. +We don't want to make an active node for this break yet, but we will +compute the total demerits and record them in the |minimal_demerits| array, +if such a break is the current champion among all ways to get to |cur_p| +in a given line-number class and fitness class. + +@<Record a new feasible break@>= +if (artificial_demerits) d=0; +else@<Compute the demerits, |d|, from |r| to |cur_p|@>; +#ifdef @!STAT +if (tracing_paragraphs > 0) + @<Print a symbolic description of this feasible break@>; +#endif +@;@/ +d=d+total_demerits(r); /*this is the minimum total demerits + from the beginning to |cur_p| via |r|*/ +if (d <= minimal_demerits[fit_class]) + {@+minimal_demerits[fit_class]=d; + best_place[fit_class]=break_node(r);best_pl_line[fit_class]=l; + if (d < minimum_demerits) minimum_demerits=d; + } + +@ @<Print a symbolic description of this feasible break@>= +{@+if (printed_node!=cur_p) + @<Print the list between |printed_node| and |cur_p|, then set |printed_node:=cur_p|@>; +print_nl("@@"); +@.\AT@> +if (cur_p==null) print_esc("par"); +else if (type(cur_p)!=glue_node) + {@+if (type(cur_p)==penalty_node) print_esc("penalty"); + else if (type(cur_p)==disc_node) print_esc("discretionary"); + else if (type(cur_p)==kern_node) print_esc("kern"); + else print_esc("math"); + } +print(" via @@@@"); +if (break_node(r)==null) print_char('0'); +else print_int(serial(break_node(r))); +print(" b="); +if (b > inf_bad) print_char('*');@+else print_int(b); +@.*\relax@> +print(" p=");print_int(pi);print(" d="); +if (artificial_demerits) print_char('*');@+else print_int(d); +} + +@ @<Print the list between |printed_node| and |cur_p|...@>= +{@+print_nl(""); +if (cur_p==null) short_display(link(printed_node)); +else{@+save_link=link(cur_p); + link(cur_p)=null;print_nl("");short_display(link(printed_node)); + link(cur_p)=save_link; + } +printed_node=cur_p; +} + +@ When the data for a discretionary break is being displayed, we will have +printed the |pre_break| and |post_break| lists; we want to skip over the +third list, so that the discretionary data will not appear twice. The +following code is performed at the very end of |try_break|. + +@<Update the value of |printed_node|...@>= +if (cur_p==printed_node) if (cur_p!=null) if (type(cur_p)==disc_node) + {@+t=replace_count(cur_p); + while (t > 0) + {@+decr(t);printed_node=link(printed_node); + } + } + +@ @<Compute the demerits, |d|, from |r| to |cur_p|@>= +{@+d=line_penalty+b; +if (abs(d) >= 10000) d=100000000;@+else d=d*d; +if (pi!=0) + if (pi > 0) d=d+pi*pi; + else if (pi > eject_penalty) d=d-pi*pi; +if ((break_type==hyphenated)&&(type(r)==hyphenated)) + if (cur_p!=null) d=d+double_hyphen_demerits; + else d=d+final_hyphen_demerits; +if (abs(fit_class-fitness(r)) > 1) d=d+adj_demerits; +} + +@ When an active node disappears, we must delete an adjacent delta node if the +active node was at the beginning or the end of the active list, or if it +was surrounded by delta nodes. We also must preserve the property that +|cur_active_width| represents the length of material from |link(prev_r)| +to~|cur_p|. + +@d combine_two_deltas(A) @|mem[prev_r+A].sc=mem[prev_r+A].sc+mem[r+A].sc +@d downdate_width(A) @|cur_active_width[A]=cur_active_width[A]- + mem[prev_r+A].sc + +@<Deactivate node |r|@>= +link(prev_r)=link(r);free_node(r, active_node_size); +if (prev_r==active) @<Update the active widths, since the first active node has been +deleted@>@; +else if (type(prev_r)==delta_node) + {@+r=link(prev_r); + if (r==last_active) + {@+do_all_six(downdate_width); + link(prev_prev_r)=last_active; + free_node(prev_r, delta_node_size);prev_r=prev_prev_r; + } + else if (type(r)==delta_node) + {@+do_all_six(update_width); + do_all_six(combine_two_deltas); + link(prev_r)=link(r);free_node(r, delta_node_size); + } + } + +@ The following code uses the fact that |type(last_active)!=delta_node|. If the +active list has just become empty, we do not need to update the +|active_width| array, since it will be initialized when an active +node is next inserted. + +@d update_active(A) active_width[A]=active_width[A]+mem[r+A].sc + +@<Update the active widths,...@>= +{@+r=link(active); +if (type(r)==delta_node) + {@+do_all_six(update_active); + do_all_six(copy_to_cur_active); + link(active)=link(r);free_node(r, delta_node_size); + } +} + +@* Breaking paragraphs into lines, continued. +So far we have gotten a little way into the |line_break| routine, having +covered its important |try_break| subroutine. Now let's consider the +rest of the process. + +The main loop of |line_break| traverses the given hlist, +starting at |link(temp_head)|, and calls |try_break| at each legal +breakpoint. A variable called |auto_breaking| is set to true except +within math formulas, since glue nodes are not legal breakpoints when +they appear in formulas. + +The current node of interest in the hlist is pointed to by |cur_p|. Another +variable, |prev_p|, is usually one step behind |cur_p|, but the real +meaning of |prev_p| is this: If |type(cur_p)==glue_node| then |cur_p| is a legal +breakpoint if and only if |auto_breaking| is true and |prev_p| does not +point to a glue node, penalty node, explicit kern node, or math node. + +The following declarations provide for a few other local variables that are +used in special calculations. + +@<Local variables for line breaking@>= +bool @!auto_breaking; /*is node |cur_p| outside a formula?*/ +pointer @!prev_p; /*helps to determine when glue nodes are breakpoints*/ +pointer @!q, @!r, @!s, @!prev_s; /*miscellaneous nodes of temporary interest*/ +internal_font_number @!f; /*used when calculating character widths*/ + +@ The `\ignorespaces|loop|\unskip' in the following code is performed at most +thrice per call of |line_break|, since it is actually a pass over the +entire paragraph. + +@<Find optimal breakpoints@>= +threshold=pretolerance; +if (threshold >= 0) + { +#ifdef @!STAT +if (tracing_paragraphs > 0) + {@+begin_diagnostic();print_nl("@@firstpass");@+} @; +#endif +@;@/ + second_pass=false;final_pass=false; + } +else{@+threshold=tolerance;second_pass=true; + final_pass=(emergency_stretch <= 0); +#ifdef @!STAT + if (tracing_paragraphs > 0) begin_diagnostic(); +#endif +@; + } +loop@+{@+if (threshold > inf_bad) threshold=inf_bad; + if (second_pass) @<Initialize for hyphenating a paragraph@>; + @<Create an active breakpoint representing the beginning of the paragraph@>; + cur_p=link(temp_head);auto_breaking=true;@/ + prev_p=cur_p; /*glue at beginning is not a legal breakpoint*/ + while ((cur_p!=null)&&(link(active)!=last_active)) + @<Call |try_break| if |cur_p| is a legal breakpoint; on the second pass, also +try to hyphenate the next word, if |cur_p| is a glue node; then advance |cur_p| to +the next node of the paragraph that could possibly be a legal breakpoint@>; + if (cur_p==null) + @<Try the final line break at the end of the paragraph, and |goto done| if the +desired breakpoints have been found@>; + @<Clean up the memory by removing the break nodes@>; + if (!second_pass) + { +#ifdef @!STAT +if (tracing_paragraphs > 0) print_nl("@@secondpass");@; +#endif + threshold=tolerance;second_pass=true;final_pass=(emergency_stretch <= 0); + } /*if at first you don't succeed, \dots*/ + else{ +#ifdef @!STAT +if (tracing_paragraphs > 0) + print_nl("@@emergencypass");@; +#endif + background[2]=background[2]+emergency_stretch;final_pass=true; + } + } +done: +#ifdef @!STAT +if (tracing_paragraphs > 0) + {@+end_diagnostic(true);normalize_selector(); + } +#endif + +@ The active node that represents the starting point does not need a +corresponding passive node. + +@d store_background(A) active_width[A]=background[A] + +@<Create an active breakpoint representing the beginning of the paragraph@>= +q=get_node(active_node_size); +type(q)=unhyphenated;fitness(q)=decent_fit; +link(q)=last_active;break_node(q)=null; +line_number(q)=prev_graf+1;total_demerits(q)=0;link(active)=q; +do_all_six(store_background);@/ +passive=null;printed_node=temp_head;pass_number=0; +font_in_short_display=null_font + +@ @<Clean...@>= +q=link(active); +while (q!=last_active) + {@+cur_p=link(q); + if (type(q)==delta_node) free_node(q, delta_node_size); + else free_node(q, active_node_size); + q=cur_p; + } +q=passive; +while (q!=null) + {@+cur_p=link(q); + free_node(q, passive_node_size); + q=cur_p; + } + +@ Here is the main switch in the |line_break| routine, where legal breaks +are determined. As we move through the hlist, we need to keep the |active_width| +array up to date, so that the badness of individual lines is readily calculated +by |try_break|. It is convenient to use the short name |act_width| for +the component of active width that represents real width as opposed to glue. + +@d act_width active_width[1] /*length from first active node to current node*/ +@d kern_break {@+if (!is_char_node(link(cur_p))&&auto_breaking) + if (type(link(cur_p))==glue_node) try_break(0, unhyphenated); + act_width=act_width+width(cur_p); + } + +@<Call |try_break| if |cur_p| is a legal breakpoint...@>= +{@+if (is_char_node(cur_p)) + @<Advance \(c)|cur_p| to the node following the present string of characters@>; +switch (type(cur_p)) { +case hlist_node: case vlist_node: case rule_node: act_width=act_width+width(cur_p);@+break; +case whatsit_node: @<Advance \(p)past a whatsit node in the \(l)|line_break| loop@>@;@+break; +case glue_node: {@+@<If node |cur_p| is a legal breakpoint, call |try_break|; then +update the active widths by including the glue in |glue_ptr(cur_p)|@>; + if (second_pass&&auto_breaking) + hyphenate_word(); + } @+break; +case kern_node: if (subtype(cur_p)==explicit) kern_break@; + else act_width=act_width+width(cur_p);@+break; +case ligature_node: {@+f=font(lig_char(cur_p)); + act_width=act_width+char_width(f, char_info(f, character(lig_char(cur_p)))); + } @+break; +case disc_node: @<Try to break after a discretionary fragment, then |goto done5|@>@; +case math_node: {@+auto_breaking=(subtype(cur_p)==after);kern_break; + } @+break; +case penalty_node: try_break(penalty(cur_p), unhyphenated);@+break; +case mark_node: case ins_node: case adjust_node: do_nothing;@+break; +default:confusion("paragraph"); +@:this can't happen paragraph}{\quad paragraph@> +} @/ +prev_p=cur_p;cur_p=link(cur_p); +done5: ;} + +@ The code that passes over the characters of words in a paragraph is +part of \TeX's inner loop, so it has been streamlined for speed. We use +the fact that `\.{\\parfillskip}' glue appears at the end of each paragraph; +it is therefore unnecessary to check if |link(cur_p)==null| when |cur_p| is a +character node. +@^inner loop@> + +@<Advance \(c)|cur_p| to the node following the present string...@>= +{@+prev_p=cur_p; +@/do@+{f=font(cur_p); +act_width=act_width+char_width(f, char_info(f, character(cur_p))); +cur_p=link(cur_p); +}@+ while (!(!is_char_node(cur_p))); +} + +@ When node |cur_p| is a glue node, we look at |prev_p| to see whether or not +a breakpoint is legal at |cur_p|, as explained above. + +@<If node |cur_p| is a legal breakpoint, call...@>= +if (auto_breaking) + {@+if (is_char_node(prev_p)) try_break(0, unhyphenated); + else if (precedes_break(prev_p)) try_break(0, unhyphenated); + else if ((type(prev_p)==kern_node)&&(subtype(prev_p)!=explicit)) + try_break(0, unhyphenated); + } +check_shrinkage(glue_ptr(cur_p));q=glue_ptr(cur_p); +act_width=act_width+width(q);@| +active_width[2+stretch_order(q)]=@| + active_width[2+stretch_order(q)]+stretch(q);@/ +active_width[6]=active_width[6]+shrink(q) + +@ The following code knows that discretionary texts contain +only character nodes, kern nodes, box nodes, rule nodes, and ligature nodes. + +@<Try to break after a discretionary fragment...@>= +{@+s=pre_break(cur_p);disc_width=0; +if (s==null) try_break(ex_hyphen_penalty, hyphenated); +else{@+@/do@+{@<Add the width of node |s| to |disc_width|@>; + s=link(s); + }@+ while (!(s==null)); + act_width=act_width+disc_width; + try_break(hyphen_penalty, hyphenated); + act_width=act_width-disc_width; + } +r=replace_count(cur_p);s=link(cur_p); +while (r > 0) + {@+@<Add the width of node |s| to |act_width|@>; + decr(r);s=link(s); + } +prev_p=cur_p;cur_p=s;goto done5; +} + +@ @<Add the width of node |s| to |disc_width|@>= +if (is_char_node(s)) + {@+f=font(s); + disc_width=disc_width+char_width(f, char_info(f, character(s))); + } +else switch (type(s)) { + case ligature_node: {@+f=font(lig_char(s)); + disc_width=disc_width+ + char_width(f, char_info(f, character(lig_char(s)))); + } @+break; + case hlist_node: case vlist_node: case rule_node: case kern_node: + disc_width=disc_width+width(s);@+break; + default:confusion("disc3"); +@:this can't happen disc3}{\quad disc3@> + } + +@ @<Add the width of node |s| to |act_width|@>= +if (is_char_node(s)) + {@+f=font(s); + act_width=act_width+char_width(f, char_info(f, character(s))); + } +else switch (type(s)) { + case ligature_node: {@+f=font(lig_char(s)); + act_width=act_width+ + char_width(f, char_info(f, character(lig_char(s)))); + } @+break; + case hlist_node: case vlist_node: case rule_node: case kern_node: + act_width=act_width+width(s);@+break; + default:confusion("disc4"); +@:this can't happen disc4}{\quad disc4@> + } + +@ The forced line break at the paragraph's end will reduce the list of +breakpoints so that all active nodes represent breaks at |cur_p==null|. +On the first pass, we insist on finding an active node that has the +correct ``looseness.'' On the final pass, there will be at least one active +node, and we will match the desired looseness as well as we can. + +The global variable |best_bet| will be set to the active node for the best +way to break the paragraph, and a few other variables are used to +help determine what is best. + +@<Glob...@>= +static pointer @!best_bet; /*use this passive node and its predecessors*/ +static int @!fewest_demerits; /*the demerits associated with |best_bet|*/ +static halfword @!best_line; /*line number following the last line of the new paragraph*/ +static int @!actual_looseness; /*the difference between |line_number(best_bet)| + and the optimum |best_line|*/ +static int @!line_diff; /*the difference between the current line number and + the optimum |best_line|*/ + +@ @<Try the final line break at the end of the paragraph...@>= +{@+try_break(eject_penalty, hyphenated); +if (link(active)!=last_active) + {@+@<Find an active node with fewest demerits@>; + if (looseness==0) goto done; + @<Find the best active node for the desired looseness@>; + if ((actual_looseness==looseness)||final_pass) goto done; + } +} + +@ @<Find an active node...@>= +r=link(active);fewest_demerits=awful_bad; +@/do@+{if (type(r)!=delta_node) if (total_demerits(r) < fewest_demerits) + {@+fewest_demerits=total_demerits(r);best_bet=r; + } +r=link(r); +}@+ while (!(r==last_active)); +best_line=line_number(best_bet) + +@ The adjustment for a desired looseness is a slightly more complicated +version of the loop just considered. Note that if a paragraph is broken +into segments by displayed equations, each segment will be subject to the +looseness calculation, independently of the other segments. + +@<Find the best active node...@>= +{@+r=link(active);actual_looseness=0; +@/do@+{if (type(r)!=delta_node) + {@+line_diff=line_number(r)-best_line; + if (((line_diff < actual_looseness)&&(looseness <= line_diff))||@| + ((line_diff > actual_looseness)&&(looseness >= line_diff))) + {@+best_bet=r;actual_looseness=line_diff; + fewest_demerits=total_demerits(r); + } + else if ((line_diff==actual_looseness)&&@| + (total_demerits(r) < fewest_demerits)) + {@+best_bet=r;fewest_demerits=total_demerits(r); + } + } +r=link(r); +}@+ while (!(r==last_active)); +best_line=line_number(best_bet); +} + +@ Once the best sequence of breakpoints has been found (hurray), we call on the +procedure |post_line_break| to finish the remainder of the work. +(By introducing this subprocedure, we are able to keep |line_break| +from getting extremely long.) + +@<Break the paragraph at the chosen...@>= +post_line_break(final_widow_penalty) + +@ The total number of lines that will be set by |post_line_break| +is |best_line-prev_graf-1|. The last breakpoint is specified by +|break_node(best_bet)|, and this passive node points to the other breakpoints +via the |prev_break| links. The finishing-up phase starts by linking the +relevant passive nodes in forward order, changing |prev_break| to +|next_break|. (The |next_break| fields actually reside in the same memory +space as the |prev_break| fields did, but we give them a new name because +of their new significance.) Then the lines are justified, one by one. + +@d next_break prev_break /*new name for |prev_break| after links are reversed*/ + +@<Declare subprocedures for |line_break|@>= +static void post_line_break(int @!final_widow_penalty) +{@+ +pointer q, @!r, @!s; /*temporary registers for list manipulation*/ +bool @!disc_break; /*was the current break at a discretionary node?*/ +bool @!post_disc_break; /*and did it have a nonempty post-break part?*/ +scaled @!cur_width; /*width of line number |cur_line|*/ +scaled @!cur_indent; /*left margin of line number |cur_line|*/ +quarterword @!t; /*used for replacement counts in discretionary nodes*/ +int @!pen; /*use when calculating penalties between lines*/ +halfword @!cur_line; /*the current line number being justified*/ +@<Reverse the links of the relevant passive nodes, setting |cur_p| to the first breakpoint@>; +cur_line=prev_graf+1; +@/do@+{@<Justify the line ending at breakpoint |cur_p|, and append it to the current +vertical list, together with associated penalties and other insertions@>; +incr(cur_line);cur_p=next_break(cur_p); +if (cur_p!=null) if (!post_disc_break) + @<Prune unwanted nodes at the beginning of the next line@>; +}@+ while (!(cur_p==null)); +if ((cur_line!=best_line)||(link(temp_head)!=null)) + confusion("line breaking"); +@:this can't happen line breaking}{\quad line breaking@> +prev_graf=best_line-1; +} + +@ The job of reversing links in a list is conveniently regarded as the job +of taking items off one stack and putting them on another. In this case we +take them off a stack pointed to by |q| and having |prev_break| fields; +we put them on a stack pointed to by |cur_p| and having |next_break| fields. +Node |r| is the passive node being moved from stack to stack. + +@<Reverse the links of the relevant passive nodes...@>= +q=break_node(best_bet);cur_p=null; +@/do@+{r=q;q=prev_break(q);next_break(r)=cur_p;cur_p=r; +}@+ while (!(q==null)) + +@ Glue and penalty and kern and math nodes are deleted at the beginning of +a line, except in the anomalous case that the node to be deleted is actually +one of the chosen breakpoints. Otherwise +the pruning done here is designed to match +the lookahead computation in |try_break|, where the |break_width| values +are computed for non-discretionary breakpoints. + +@<Prune unwanted nodes at the beginning of the next line@>= +{@+r=temp_head; +loop@+{@+q=link(r); + if (q==cur_break(cur_p)) goto done1; + /*|cur_break(cur_p)| is the next breakpoint*/ + /*now |q| cannot be |null|*/ + if (is_char_node(q)) goto done1; + if (non_discardable(q)) goto done1; + if (type(q)==kern_node) if (subtype(q)!=explicit) goto done1; + r=q; /*now |type(q)==glue_node|, |kern_node|, |math_node| or |penalty_node|*/ + } +done1: if (r!=temp_head) + {@+link(r)=null;flush_node_list(link(temp_head)); + link(temp_head)=q; + } +} + +@ The current line to be justified appears in a horizontal list starting +at |link(temp_head)| and ending at |cur_break(cur_p)|. If |cur_break(cur_p)| is +a glue node, we reset the glue to equal the |right_skip| glue; otherwise +we append the |right_skip| glue at the right. If |cur_break(cur_p)| is a +discretionary node, we modify the list so that the discretionary break +is compulsory, and we set |disc_break| to |true|. We also append +the |left_skip| glue at the left of the line, unless it is zero. + +@<Justify the line ending at breakpoint |cur_p|, and append it...@>= +@<Modify the end of the line to reflect the nature of the break and to include \.{\\rightskip}; +also set the proper value of |disc_break|@>; +@<Put the \(l)\.{\\leftskip} glue at the left and detach this line@>; +@<Call the packaging subroutine, setting |just_box| to the justified box@>; +@<Append the new box to the current vertical list, followed by the list of special +nodes taken out of the box by the packager@>; +@<Append a penalty node, if a nonzero penalty is appropriate@>@; + +@ At the end of the following code, |q| will point to the final node on the +list about to be justified. + +@<Modify the end of the line...@>= +q=cur_break(cur_p);disc_break=false;post_disc_break=false; +if (q!=null) /*|q| cannot be a |char_node|*/ + if (type(q)==glue_node) + {@+delete_glue_ref(glue_ptr(q)); + glue_ptr(q)=right_skip; + subtype(q)=right_skip_code+1;add_glue_ref(right_skip); + goto done; + } + else{@+if (type(q)==disc_node) + @<Change discretionary to compulsory and set |disc_break:=true|@>@; + else if ((type(q)==math_node)||(type(q)==kern_node)) width(q)=0; + } +else{@+q=temp_head; + while (link(q)!=null) q=link(q); + } +@<Put the \(r)\.{\\rightskip} glue after node |q|@>; +done: + +@ @<Change discretionary to compulsory...@>= +{@+t=replace_count(q); +@<Destroy the |t| nodes following |q|, and make |r| point to the following node@>; +if (post_break(q)!=null) @<Transplant the post-break list@>; +if (pre_break(q)!=null) @<Transplant the pre-break list@>; +link(q)=r;disc_break=true; +} + +@ @<Destroy the |t| nodes following |q|...@>= +if (t==0) r=link(q); +else{@+r=q; + while (t > 1) + {@+r=link(r);decr(t); + } + s=link(r); + r=link(s);link(s)=null; + flush_node_list(link(q));set_replace_count(q,0); + } + +@ We move the post-break list from inside node |q| to the main list by +re\-attaching it just before the present node |r|, then resetting |r|. + +@<Transplant the post-break list@>= +{@+s=post_break(q); +while (link(s)!=null) s=link(s); +link(s)=r;r=post_break(q);post_break(q)=null;post_disc_break=true; +} + +@ We move the pre-break list from inside node |q| to the main list by +re\-attaching it just after the present node |q|, then resetting |q|. + +@<Transplant the pre-break list@>= +{@+s=pre_break(q);link(q)=s; +while (link(s)!=null) s=link(s); +pre_break(q)=null;q=s; +} + +@ @<Put the \(r)\.{\\rightskip} glue after node |q|@>= +r=new_param_glue(right_skip_code);link(r)=link(q);link(q)=r;q=r + +@ The following code begins with |q| at the end of the list to be +justified. It ends with |q| at the beginning of that list, and with +|link(temp_head)| pointing to the remainder of the paragraph, if any. + +@<Put the \(l)\.{\\leftskip} glue at the left...@>= +r=link(q);link(q)=null;q=link(temp_head);link(temp_head)=r; +if (left_skip!=zero_glue) + {@+r=new_param_glue(left_skip_code); + link(r)=q;q=r; + } + +@ @<Append the new box to the current vertical list...@>= +append_to_vlist(just_box); +if (adjust_head!=adjust_tail) + {@+link(tail)=link(adjust_head);tail=adjust_tail; + } +adjust_tail=null + +@ Now |q| points to the hlist that represents the current line of the +paragraph. We need to compute the appropriate line width, pack the +line into a box of this size, and shift the box by the appropriate +amount of indentation. + +@<Call the packaging subroutine...@>= +if (cur_line > last_special_line) + {@+cur_width=second_width;cur_indent=second_indent; + } +else if (par_shape_ptr==null) + {@+cur_width=first_width;cur_indent=first_indent; + } +else{@+cur_width=mem[par_shape_ptr+2*cur_line].sc; + cur_indent=mem[par_shape_ptr+2*cur_line-1].sc; + } +adjust_tail=adjust_head;just_box=hpack(q, cur_width, 0, 0, exactly); +shift_amount(just_box)=cur_indent + +@ Penalties between the lines of a paragraph come from club and widow lines, +from the |inter_line_penalty| parameter, and from lines that end at +discretionary breaks. Breaking between lines of a two-line paragraph gets +both club-line and widow-line penalties. The local variable |pen| will +be set to the sum of all relevant penalties for the current line, except +that the final line is never penalized. + +@<Append a penalty node, if a nonzero penalty is appropriate@>= +if (cur_line+1!=best_line) + {@+pen=inter_line_penalty; + if (cur_line==prev_graf+1) pen=pen+club_penalty; + if (cur_line+2==best_line) pen=pen+final_widow_penalty; + if (disc_break) pen=pen+broken_penalty; + if (pen!=0) + {@+r=new_penalty(pen); + link(tail)=r;tail=r; + } + } + +@* Pre-hyphenation. +When the line-breaking routine is unable to find a feasible sequence of +breakpoints, it makes a second pass over the paragraph, attempting to +hyphenate the hyphenatable words. The goal of hyphenation is to insert +discretionary material into the paragraph so that there are more +potential places to break. + +The general rules for hyphenation are somewhat complex and technical, +because we want to be able to hyphenate words that are preceded or +followed by punctuation marks, and because we want the rules to work +for languages other than English. We also must contend with the fact +that hyphens might radically alter the ligature and kerning structure +of a word. + +A sequence of characters will be considered for hyphenation only if it +belongs to a ``potentially hyphenatable part'' of the current paragraph. +This is a sequence of nodes $p_0p_1\ldots p_m$ where $p_0$ is a glue node, +$p_1\ldots p_{m-1}$ are either character or ligature or whatsit or +implicit kern nodes, and $p_m$ is a glue or penalty or insertion or adjust +or mark or whatsit or explicit kern node. (Therefore hyphenation is +disabled by boxes, math formulas, and discretionary nodes already inserted +by the user.) The ligature nodes among $p_1\ldots p_{m-1}$ are effectively +expanded into the original non-ligature characters; the kern nodes and +whatsits are ignored. Each character |c| is now classified as either a +nonletter (if |lc_code(c)==0|), a lowercase letter (if +|lc_code(c)==c|), or an uppercase letter (otherwise); an uppercase letter +is treated as if it were |lc_code(c)| for purposes of hyphenation. The +characters generated by $p_1\ldots p_{m-1}$ may begin with nonletters; let +$c_1$ be the first letter that is not in the middle of a ligature. Whatsit +nodes preceding $c_1$ are ignored; a whatsit found after $c_1$ will be the +terminating node $p_m$. All characters that do not have the same font as +$c_1$ will be treated as nonletters. The |hyphen_char| for that font +must be between 0 and 255, otherwise hyphenation will not be attempted. +\TeX\ looks ahead for as many consecutive letters $c_1\ldots c_n$ as +possible; however, |n| must be less than 64, so a character that would +otherwise be $c_{64}$ is effectively not a letter. Furthermore $c_n$ must +not be in the middle of a ligature. In this way we obtain a string of +letters $c_1\ldots c_n$ that are generated by nodes $p_a\ldots p_b$, where +|1 <= a <= b+1 <= m|. If |n >= l_hyf+r_hyf|, this string qualifies for hyphenation; +however, |uc_hyph| must be positive, if $c_1$ is uppercase. + +The hyphenation process takes place in three stages. First, the candidate +sequence $c_1\ldots c_n$ is found; then potential positions for hyphens +are determined by referring to hyphenation tables; and finally, the nodes +$p_a\ldots p_b$ are replaced by a new sequence of nodes that includes the +discretionary breaks found. + +Fortunately, we do not have to do all this calculation very often, because +of the way it has been taken out of \TeX's inner loop. For example, when +the second edition of the author's 700-page book {\sl Seminumerical +Algorithms} was typeset by \TeX, only about 1.2 hyphenations needed to be +@^Knuth, Donald Ervin@> +tried per paragraph, since the line breaking algorithm needed to use two +passes on only about 5 per cent of the paragraphs. + +@<Initialize for hyphenating...@>= +{ +#ifdef @!INIT +if (trie_not_ready) init_trie(); +#endif +@;@/ +cur_lang=init_cur_lang;l_hyf=init_l_hyf;r_hyf=init_r_hyf; +} + +@ The letters $c_1\ldots c_n$ that are candidates for hyphenation are placed +into an array called |hc|; the number |n| is placed into |hn|; pointers to +nodes $p_{a-1}$ and~$p_b$ in the description above are placed into variables +|ha| and |hb|; and the font number is placed into |hf|. + +@<Glob...@>= +static int16_t @!hc[66]; /*word to be hyphenated*/ +static small_number @!hn; /*the number of positions occupied in |hc|*/ +static pointer @!ha, @!hb; /*nodes |ha dotdot hb| should be replaced by the hyphenated result*/ +static internal_font_number @!hf; /*font number of the letters in |hc|*/ +static int16_t @!hu[64]; /*like |hc|, before conversion to lowercase*/ +static int @!hyf_char; /*hyphen character of the relevant font*/ +ASCII_code @!cur_lang, @!init_cur_lang; /*current hyphenation table of interest*/ +int @!l_hyf, @!r_hyf, @!init_l_hyf, @!init_r_hyf; /*limits on fragment sizes*/ +static halfword @!hyf_bchar; /*boundary character after $c_n$*/ + +@ Hyphenation routines need a few more local variables. + +@<Local variables for line...@>= +small_number @!j; /*an index into |hc| or |hu|*/ +int @!c; /*character being considered for hyphenation*/ + +@ When the following code is activated, the |line_break| procedure is in its +second pass, and |cur_p| points to a glue node. + +@p +void hyphenate_word(void)@t\2\2@>@/ +{ pointer @!q, @!s, @!prev_s;@t\1@> /*miscellaneous nodes of temporary interest*/ + small_number @!j; /*an index into |hc| or |hu|*/ + uint8_t @!c; /*character being considered for hyphenation*/ + + prev_s=cur_p;s=link(prev_s); +if (s!=null) + {@+@<Skip to node |ha|, or |goto done1| if no hyphenation should be attempted@>; + if (l_hyf+r_hyf > 63) goto done1; + @<Skip to node |hb|, putting letters into |hu| and |hc|@>; + @<Check that the nodes following |hb| permit hyphenation and that at least |l_hyf+r_hyf| +letters have been found, otherwise |goto done1|@>; + hyphenate(); + } +done1: ;} + +@ @<Declare subprocedures for |line_break|@>= +@t\4@>@<Declare the function called |reconstitute|@>@; +static void hyphenate(void) +{@+ +@<Local variables for hyphenation@>@; +@<Find hyphen locations for the word in |hc|, or |return|@>; +@<If no hyphens were found, |return|@>; +@<Replace nodes |ha..hb| by a sequence of nodes that includes the discretionary hyphens@>; +} + +@ The first thing we need to do is find the node |ha| just before the +first letter. + +@<Skip to node |ha|, or |goto done1|...@>= +loop@+{@+if (is_char_node(s)) + {@+c=qo(character(s));hf=font(s); + } + else if (type(s)==ligature_node) + if (lig_ptr(s)==null) goto resume; + else{@+q=lig_ptr(s);c=qo(character(q));hf=font(q); + } + else if ((type(s)==kern_node)&&(subtype(s)==normal)) goto resume; + else if (type(s)==whatsit_node) + {@+@<Advance \(p)past a whatsit node in the \(p)pre-hyphenation loop@>; + goto resume; + } + else goto done1; + if (lc_code(c)!=0) + if ((lc_code(c)==c)||(uc_hyph > 0)) goto done2; + else goto done1; +resume: prev_s=s;s=link(prev_s); + } +done2: hyf_char=hyphen_char[hf]; +if (hyf_char < 0) goto done1; +if (hyf_char > 255) goto done1; +ha=prev_s + +@ The word to be hyphenated is now moved to the |hu| and |hc| arrays. + +@<Skip to node |hb|, putting letters...@>= +hn=0; +loop@+{@+if (is_char_node(s)) + {@+if (font(s)!=hf) goto done3; + hyf_bchar=character(s);c=qo(hyf_bchar); + if (lc_code(c)==0) goto done3; + if (hn==63) goto done3; + hb=s;incr(hn);hu[hn]=c;hc[hn]=lc_code(c);hyf_bchar=non_char; + } + else if (type(s)==ligature_node) + @<Move the characters of a ligature node to |hu| and |hc|; but |goto done3| if +they are not all letters@>@; + else if ((type(s)==kern_node)&&(subtype(s)==normal)) + {@+hb=s; + hyf_bchar=font_bchar[hf]; + } + else goto done3; + s=link(s); + } +done3: + +@ We let |j| be the index of the character being stored when a ligature node +is being expanded, since we do not want to advance |hn| until we are sure +that the entire ligature consists of letters. Note that it is possible +to get to |done3| with |hn==0| and |hb| not set to any value. + +@<Move the characters of a ligature node to |hu| and |hc|...@>= +{@+if (font(lig_char(s))!=hf) goto done3; +j=hn;q=lig_ptr(s);@+if (q > null) hyf_bchar=character(q); +while (q > null) + {@+c=qo(character(q)); + if (lc_code(c)==0) goto done3; + if (j==63) goto done3; + incr(j);hu[j]=c;hc[j]=lc_code(c);@/ + q=link(q); + } +hb=s;hn=j; +if (odd(subtype(s))) hyf_bchar=font_bchar[hf];@+else hyf_bchar=non_char; +} + +@ @<Check that the nodes following |hb| permit hyphenation...@>= +if (hn < l_hyf+r_hyf) goto done1; /*|l_hyf| and |r_hyf| are | >= 1|*/ +loop@+{@+if (!(is_char_node(s))) + switch (type(s)) { + case ligature_node: do_nothing;@+break; + case kern_node: if (subtype(s)!=normal) goto done4;@+break; + case whatsit_node: case glue_node: case penalty_node: case ins_node: case adjust_node: case mark_node: + goto done4; + default:goto done1; + } + s=link(s); + } +done4: + +@* Post-hyphenation. +If a hyphen may be inserted between |hc[j]| and |hc[j+1]|, the hyphenation +procedure will set |hyf[j]| to some small odd number. But before we look +at \TeX's hyphenation procedure, which is independent of the rest of the +line-breaking algorithm, let us consider what we will do with the hyphens +it finds, since it is better to work on this part of the program before +forgetting what |ha| and |hb|, etc., are all about. + +@<Glob...@>= +static int8_t @!hyf[65]; /*odd values indicate discretionary hyphens*/ +static pointer @!init_list; /*list of punctuation characters preceding the word*/ +static bool @!init_lig; /*does |init_list| represent a ligature?*/ +static bool @!init_lft; /*if so, did the ligature involve a left boundary?*/ + +@ @<Local variables for hyphenation@>= +int @!i, @!j, @!l; /*indices into |hc| or |hu|*/ +pointer @!q, @!r, @!s; /*temporary registers for list manipulation*/ +halfword @!bchar; /*right boundary character of hyphenated word, or |non_char|*/ + +@ \TeX\ will never insert a hyphen that has fewer than +\.{\\lefthyphenmin} letters before it or fewer than +\.{\\righthyphenmin} after it; hence, a short word has +comparatively little chance of being hyphenated. If no hyphens have +been found, we can save time by not having to make any changes to the +paragraph. + +@<If no hyphens were found, |return|@>= +for (j=l_hyf; j<=hn-r_hyf; j++) if (odd(hyf[j])) goto found1; +return; +found1: + +@ If hyphens are in fact going to be inserted, \TeX\ first deletes the +subsequence of nodes between |ha| and~|hb|. An attempt is made to +preserve the effect that implicit boundary characters and punctuation marks +had on ligatures inside the hyphenated word, by storing a left boundary or +preceding character in |hu[0]| and by storing a possible right boundary +in |bchar|. We set |j=0| if |hu[0]| is to be part of the reconstruction; +otherwise |j=1|. +The variable |s| will point to the tail of the current hlist, and +|q| will point to the node following |hb|, so that +things can be hooked up after we reconstitute the hyphenated word. + +@<Replace nodes |ha..hb| by a sequence of nodes...@>= +q=link(hb);link(hb)=null;r=link(ha);link(ha)=null;bchar=hyf_bchar; +if (is_char_node(ha)) + if (font(ha)!=hf) goto found2; + else{@+init_list=ha;init_lig=false;hu[0]=qo(character(ha)); + } +else if (type(ha)==ligature_node) + if (font(lig_char(ha))!=hf) goto found2; + else{@+init_list=lig_ptr(ha);init_lig=true;init_lft=(subtype(ha) > 1); + hu[0]=qo(character(lig_char(ha))); + if (init_list==null) if (init_lft) + {@+hu[0]=256;init_lig=false; + } /*in this case a ligature will be reconstructed from scratch*/ + free_node(ha, small_node_size); + } +else{@+ /*no punctuation found; look for left boundary*/ + if (!is_char_node(r)) if (type(r)==ligature_node) + if (subtype(r) > 1) goto found2; + j=1;s=ha;init_list=null;goto common_ending; + } +s=cur_p; /*we have |cur_p!=ha| because |type(cur_p)==glue_node|*/ +while (link(s)!=ha) s=link(s); +j=0;goto common_ending; +found2: s=ha;j=0;hu[0]=256;init_lig=false;init_list=null; +common_ending: flush_node_list(r); +@<Reconstitute nodes for the hyphenated word, inserting discretionary hyphens@>; +flush_list(init_list) + +@ We must now face the fact that the battle is not over, even though the +{\def\!{\kern-1pt}% +hyphens have been found: The process of reconstituting a word can be nontrivial +because ligatures might change when a hyphen is present. {\sl The \TeX book\/} +discusses the difficulties of the word ``difficult'', and +the discretionary material surrounding a +hyphen can be considerably more complex than that. Suppose +\.{abcdef} is a word in a font for which the only ligatures are \.{b\!c}, +\.{c\!d}, \.{d\!e}, and \.{e\!f}. If this word permits hyphenation +between \.b and \.c, the two patterns with and without hyphenation are +$\.a\,\.b\,\.-\,\.{c\!d}\,\.{e\!f}$ and $\.a\,\.{b\!c}\,\.{d\!e}\,\.f$. +Thus the insertion of a hyphen might cause effects to ripple arbitrarily +far into the rest of the word. A further complication arises if additional +hyphens appear together with such rippling, e.g., if the word in the +example just given could also be hyphenated between \.c and \.d; \TeX\ +avoids this by simply ignoring the additional hyphens in such weird cases.} + +Still further complications arise in the presence of ligatures that do not +delete the original characters. When punctuation precedes the word being +hyphenated, \TeX's method is not perfect under all possible scenarios, +because punctuation marks and letters can propagate information back and forth. +For example, suppose the original pre-hyphenation pair +\.{*a} changes to \.{*y} via a \.{\@@=:} ligature, which changes to \.{xy} +via a \.{=:\@@} ligature; if $p_{a-1}=\.x$ and $p_a=\.y$, the reconstitution +procedure isn't smart enough to obtain \.{xy} again. In such cases the +font designer should include a ligature that goes from \.{xa} to \.{xy}. + +@ The processing is facilitated by a subroutine called |reconstitute|. Given +a string of characters $x_j\ldots x_n$, there is a smallest index $m\ge j$ +such that the ``translation'' of $x_j\ldots x_n$ by ligatures and kerning +has the form $y_1\ldots y_t$ followed by the translation of $x_{m+1}\ldots x_n$, +where $y_1\ldots y_t$ is some nonempty sequence of character, ligature, and +kern nodes. We call $x_j\ldots x_m$ a ``cut prefix'' of $x_j\ldots x_n$. +For example, if $x_1x_2x_3=\.{fly}$, and if the font contains `fl' as a +ligature and a kern between `fl' and `y', then $m=2$, $t=2$, and $y_1$ will +be a ligature node for `fl' followed by an appropriate kern node~$y_2$. +In the most common case, $x_j$~forms no ligature with $x_{j+1}$ and we +simply have $m=j$, $y_1=x_j$. If $m<n$ we can repeat the procedure on +$x_{m+1}\ldots x_n$ until the entire translation has been found. + +The |reconstitute| function returns the integer $m$ and puts the nodes +$y_1\ldots y_t$ into a linked list starting at |link(hold_head)|, +getting the input $x_j\ldots x_n$ from the |hu| array. If $x_j=256$, +we consider $x_j$ to be an implicit left boundary character; in this +case |j| must be strictly less than~|n|. There is a +parameter |bchar|, which is either 256 or an implicit right boundary character +assumed to be present just following~$x_n$. (The value |hu[n+1]| is never +explicitly examined, but the algorithm imagines that |bchar| is there.) + +If there exists an index |k| in the range $j\le k\le m$ such that |hyf[k]| +is odd and such that the result of |reconstitute| would have been different +if $x_{k+1}$ had been |hchar|, then |reconstitute| sets |hyphen_passed| +to the smallest such~|k|. Otherwise it sets |hyphen_passed| to zero. + +A special convention is used in the case |j==0|: Then we assume that the +translation of |hu[0]| appears in a special list of charnodes starting at +|init_list|; moreover, if |init_lig| is |true|, then |hu[0]| will be +a ligature character, involving a left boundary if |init_lft| is |true|. +This facility is provided for cases when a hyphenated +word is preceded by punctuation (like single or double quotes) that might +affect the translation of the beginning of the word. + +@<Glob...@>= +static small_number @!hyphen_passed; /*first hyphen in a ligature, if any*/ + +@ @<Declare the function called |reconstitute|@>= +static + small_number reconstitute(small_number @!j, small_number @!n, halfword @!bchar, halfword @!hchar) +{@+ +pointer @!p; /*temporary register for list manipulation*/ +pointer @!t; /*a node being appended to*/ +four_quarters @!q; /*character information or a lig/kern instruction*/ +halfword @!cur_rh; /*hyphen character for ligature testing*/ +halfword @!test_char; /*hyphen or other character for ligature testing*/ +scaled @!w; /*amount of kerning*/ +font_index @!k; /*position of current lig/kern instruction*/ +hyphen_passed=0;t=hold_head;w=0;link(hold_head)=null; + /*at this point |ligature_present==lft_hit==rt_hit==false|*/ +@<Set up data structures with the cursor following position |j|@>; +resume: @<If there's a ligature or kern at the cursor position, update the data structures, +possibly advancing~|j|; continue until the cursor moves@>; +@<Append a ligature and/or kern to the translation; |goto continue| if the stack of +inserted ligatures is nonempty@>; +return j; +} + +@ The reconstitution procedure shares many of the global data structures +by which \TeX\ has processed the words before they were hyphenated. +There is an implied ``cursor'' between characters |cur_l| and |cur_r|; +these characters will be tested for possible ligature activity. If +|ligature_present| then |cur_l| is a ligature character formed from the +original characters following |cur_q| in the current translation list. +There is a ``ligature stack'' between the cursor and character |j+1|, +consisting of pseudo-ligature nodes linked together by their |link| fields. +This stack is normally empty unless a ligature command has created a new +character that will need to be processed later. A pseudo-ligature is +a special node having a |character| field that represents a potential +ligature and a |lig_ptr| field that points to a |char_node| or is |null|. +We have +$$|cur_r|=\cases{|character(lig_stack)|,&if |lig_stack > null|;\cr + \hbox{|qi(hu[j+1])|},&if |lig_stack==null| and |j < n|;\cr + bchar,&if |lig_stack==null| and |j==n|.\cr}$$ + +@<Glob...@>= +static halfword @!cur_l, @!cur_r; /*characters before and after the cursor*/ +static pointer @!cur_q; /*where a ligature should be detached*/ +static pointer @!lig_stack; /*unfinished business to the right of the cursor*/ +static bool @!ligature_present; /*should a ligature node be made for |cur_l|?*/ +static bool @!lft_hit, @!rt_hit; /*did we hit a ligature with a boundary character?*/ + +@ @d append_charnode_to_t(A) {@+link(t)=get_avail();t=link(t); + font(t)=hf;character(t)=A; + } +@d set_cur_r {@+if (j < n) cur_r=qi(hu[j+1]);@+else cur_r=bchar; + if (odd(hyf[j])) cur_rh=hchar;@+else cur_rh=non_char; + } + +@<Set up data structures with the cursor following position |j|@>= +cur_l=qi(hu[j]);cur_q=t; +if (j==0) + {@+ligature_present=init_lig;p=init_list; + if (ligature_present) lft_hit=init_lft; + while (p > null) + {@+append_charnode_to_t(character(p));p=link(p); + } + } +else if (cur_l < non_char) append_charnode_to_t(cur_l); +lig_stack=null;set_cur_r + +@ We may want to look at the lig/kern program twice, once for a hyphen +and once for a normal letter. (The hyphen might appear after the letter +in the program, so we'd better not try to look for both at once.) + +@<If there's a ligature or kern at the cursor position, update...@>= +if (cur_l==non_char) + {@+k=bchar_label[hf]; + if (k==non_address) goto done;@+else q=font_info[k].qqqq; + } +else{@+q=char_info(hf, cur_l); + if (char_tag(q)!=lig_tag) goto done; + k=lig_kern_start(hf, q);q=font_info[k].qqqq; + if (skip_byte(q) > stop_flag) + {@+k=lig_kern_restart(hf, q);q=font_info[k].qqqq; + } + } /*now |k| is the starting address of the lig/kern program*/ +if (cur_rh < non_char) test_char=cur_rh;@+else test_char=cur_r; +loop@+{@+if (next_char(q)==test_char) if (skip_byte(q) <= stop_flag) + if (cur_rh < non_char) + {@+hyphen_passed=j;hchar=non_char;cur_rh=non_char; + goto resume; + } + else{@+if (hchar < non_char) if (odd(hyf[j])) + {@+hyphen_passed=j;hchar=non_char; + } + if (op_byte(q) < kern_flag) + @<Carry out a ligature replacement, updating the cursor structure and possibly +advancing~|j|; |goto continue| if the cursor doesn't advance, otherwise |goto done|@>; + w=char_kern(hf, q);goto done; /*this kern will be inserted below*/ + } + if (skip_byte(q) >= stop_flag) + if (cur_rh==non_char) goto done; + else{@+cur_rh=non_char;goto resume; + } + k=k+qo(skip_byte(q))+1;q=font_info[k].qqqq; + } +done: + +@ @d wrap_lig(A) if (ligature_present) + {@+p=new_ligature(hf, cur_l, link(cur_q)); + if (lft_hit) + {@+subtype(p)=2;lft_hit=false; + } + if (A) if (lig_stack==null) + {@+incr(subtype(p));rt_hit=false; + } + link(cur_q)=p;t=p;ligature_present=false; + } +@d pop_lig_stack {@+if (lig_ptr(lig_stack) > null) + {@+link(t)=lig_ptr(lig_stack); /*this is a charnode for |hu[j+1]|*/ + t=link(t);incr(j); + } + p=lig_stack;lig_stack=link(p);free_node(p, small_node_size); + if (lig_stack==null) set_cur_r@;@+else cur_r=character(lig_stack); + } /*if |lig_stack| isn't |null| we have |cur_rh==non_char|*/ + +@<Append a ligature and/or kern to the translation...@>= +wrap_lig(rt_hit); +if (w!=0) + {@+link(t)=new_kern(w);t=link(t);w=0; + } +if (lig_stack > null) + {@+cur_q=t;cur_l=character(lig_stack);ligature_present=true; + pop_lig_stack;goto resume; + } + +@ @<Carry out a ligature replacement, updating the cursor structure...@>= +{@+if (cur_l==non_char) lft_hit=true; +if (j==n) if (lig_stack==null) rt_hit=true; +check_interrupt; /*allow a way out in case there's an infinite ligature loop*/ +switch (op_byte(q)) { +case qi(1): case qi(5): {@+cur_l=rem_byte(q); /*\.{=:\@@}, \.{=:\@@>}*/ + ligature_present=true; + } @+break; +case qi(2): case qi(6): {@+cur_r=rem_byte(q); /*\.{\@@=:}, \.{\@@=:>}*/ + if (lig_stack > null) character(lig_stack)=cur_r; + else{@+lig_stack=new_lig_item(cur_r); + if (j==n) bchar=non_char; + else{@+p=get_avail();lig_ptr(lig_stack)=p; + character(p)=qi(hu[j+1]);font(p)=hf; + } + } + } @+break; +case qi(3): {@+cur_r=rem_byte(q); /*\.{\@@=:\@@}*/ + p=lig_stack;lig_stack=new_lig_item(cur_r);link(lig_stack)=p; + } @+break; +case qi(7): case qi(11): {@+wrap_lig(false); /*\.{\@@=:\@@>}, \.{\@@=:\@@>>}*/ + cur_q=t;cur_l=rem_byte(q);ligature_present=true; + } @+break; +default:{@+cur_l=rem_byte(q);ligature_present=true; /*\.{=:}*/ + if (lig_stack > null) pop_lig_stack@; + else if (j==n) goto done; + else{@+append_charnode_to_t(cur_r);incr(j);set_cur_r; + } + } +} +if (op_byte(q) > qi(4)) if (op_byte(q)!=qi(7)) goto done; +goto resume; +} + +@ Okay, we're ready to insert the potential hyphenations that were found. +When the following program is executed, we want to append the word +|hu[1 dotdot hn]| after node |ha|, and node |q| should be appended to the result. +During this process, the variable |i| will be a temporary +index into |hu|; the variable |j| will be an index to our current position +in |hu|; the variable |l| will be the counterpart of |j|, in a discretionary +branch; the variable |r| will point to new nodes being created; and +we need a few new local variables: + +@<Local variables for hyph...@>= +pointer @!major_tail, @!minor_tail; /*the end of lists in the main and + discretionary branches being reconstructed*/ +ASCII_code @!c; /*character temporarily replaced by a hyphen*/ +int @!c_loc; /*where that character came from*/ +int @!r_count; /*replacement count for discretionary*/ +pointer @!hyf_node; /*the hyphen, if it exists*/ + +@ When the following code is performed, |hyf[0]| and |hyf[hn]| will be zero. + +@<Reconstitute nodes for the hyphenated word...@>= +@/do@+{l=j;j=reconstitute(j, hn, bchar, qi(hyf_char))+1; +if (hyphen_passed==0) + {@+link(s)=link(hold_head); + while (link(s) > null) s=link(s); + if (odd(hyf[j-1])) + {@+l=j;hyphen_passed=j-1;link(hold_head)=null; + } + } +if (hyphen_passed > 0) + @<Create and append a discretionary node as an alternative to the unhyphenated word, +and continue to develop both branches until they become equivalent@>; +}@+ while (!(j > hn)); +link(s)=q + +@ In this repeat loop we will insert another discretionary if |hyf[j-1]| is +odd, when both branches of the previous discretionary end at position |j-1|. +Strictly speaking, we aren't justified in doing this, because we don't know +that a hyphen after |j-1| is truly independent of those branches. But in almost +all applications we would rather not lose a potentially valuable hyphenation +point. (Consider the word `difficult', where the letter `c' is in position |j|.) + +@d advance_major_tail {@+major_tail=link(major_tail);incr(r_count); + } + +@<Create and append a discretionary node as an alternative...@>= +@/do@+{r=get_node(small_node_size); +link(r)=link(hold_head);type(r)=disc_node; +major_tail=r;r_count=0; +while (link(major_tail) > null) advance_major_tail; +i=hyphen_passed;hyf[i]=0; +@<Put the \(c)characters |hu[l..i]| and a hyphen into |pre_break(r)|@>; +@<Put the \(c)characters |hu[i+1..]| into |post_break(r)|, appending to this list +and to |major_tail| until synchronization has been achieved@>; +@<Move pointer |s| to the end of the current list, and set |replace_count(r)| appropriately@>; +hyphen_passed=j-1;link(hold_head)=null; +}@+ while (!(!odd(hyf[j-1]))) + +@ The new hyphen might combine with the previous character via ligature +or kern. At this point we have |l-1 <= i < j| and |i < hn|. + +@<Put the \(c)characters |hu[l..i]| and a hyphen into |pre_break(r)|@>= +minor_tail=null;pre_break(r)=null;hyf_node=new_character(hf, hyf_char); +if (hyf_node!=null) + {@+incr(i);c=hu[i];hu[i]=hyf_char;free_avail(hyf_node); + } +while (l <= i) + {@+l=reconstitute(l, i, font_bchar[hf], non_char)+1; + if (link(hold_head) > null) + {@+if (minor_tail==null) pre_break(r)=link(hold_head); + else link(minor_tail)=link(hold_head); + minor_tail=link(hold_head); + while (link(minor_tail) > null) minor_tail=link(minor_tail); + } + } +if (hyf_node!=null) + {@+hu[i]=c; /*restore the character in the hyphen position*/ + l=i;decr(i); + } + +@ The synchronization algorithm begins with |l==i+1 <= j|. + +@<Put the \(c)characters |hu[i+1..]| into |post_break(r)|...@>= +minor_tail=null;post_break(r)=null;c_loc=0; +if (bchar_label[hf]!=non_address) /*put left boundary at beginning of new line*/ + {@+decr(l);c=hu[l];c_loc=l;hu[l]=256; + } +while (l < j) + {@+@/do@+{l=reconstitute(l, hn, bchar, non_char)+1; + if (c_loc > 0) + {@+hu[c_loc]=c;c_loc=0; + } + if (link(hold_head) > null) + {@+if (minor_tail==null) post_break(r)=link(hold_head); + else link(minor_tail)=link(hold_head); + minor_tail=link(hold_head); + while (link(minor_tail) > null) minor_tail=link(minor_tail); + } + }@+ while (!(l >= j)); + while (l > j) + @<Append characters of |hu[j..]| to |major_tail|, advancing~|j|@>; + } + +@ @<Append characters of |hu[j..]|...@>= +{@+j=reconstitute(j, hn, bchar, non_char)+1; +link(major_tail)=link(hold_head); +while (link(major_tail) > null) advance_major_tail; +} + +@ Ligature insertion can cause a word to grow exponentially in size. Therefore +we must test the size of |r_count| here, even though the hyphenated text +was at most 63 characters long. + +@<Move pointer |s| to the end of the current list...@>= +if (r_count > 127) /*we have to forget the discretionary hyphen*/ + {@+link(s)=link(r);link(r)=null;flush_node_list(r); + } +else{@+link(s)=r;set_replace_count(r,r_count);set_auto_disc(r); + } +s=major_tail + +@* Hyphenation. +When a word |hc[1 dotdot hn]| has been set up to contain a candidate for hyphenation, +\TeX\ first looks to see if it is in the user's exception dictionary. If not, +hyphens are inserted based on patterns that appear within the given word, +using an algorithm due to Frank~M. Liang. +@^Liang, Franklin Mark@> + +Let's consider Liang's method first, since it is much more interesting than the +exception-lookup routine. The algorithm begins by setting |hyf[j]| to zero +for all |j|, and invalid characters are inserted into |hc[0]| +and |hc[hn+1]| to serve as delimiters. Then a reasonably fast method is +used to see which of a given set of patterns occurs in the word +|hc[0 dotdot(hn+1)]|. Each pattern $p_1\ldots p_k$ of length |k| has an associated +sequence of |k+1| numbers $n_0\ldots n_k$; and if the pattern occurs in +|hc[(j+1)dotdot(j+k)]|, \TeX\ will set |hyf[j+i]=@tmax@>(hyf[j+i],@t$n\_i$@>)| for +|0 <= i <= k|. After this has been done for each pattern that occurs, a +discretionary hyphen will be inserted between |hc[j]| and |hc[j+1]| when +|hyf[j]| is odd, as we have already seen. + +The set of patterns $p_1\ldots p_k$ and associated numbers $n_0\ldots n_k$ +depends, of course, on the language whose words are being hyphenated, and +on the degree of hyphenation that is desired. A method for finding +appropriate |p|'s and |n|'s, from a given dictionary of words and acceptable +hyphenations, is discussed in Liang's Ph.D. thesis (Stanford University, +1983); \TeX\ simply starts with the patterns and works from there. + +@ The patterns are stored in a compact table that is also efficient for +retrieval, using a variant of ``trie memory'' [cf.\ {\sl The Art of +Computer Programming \bf3} (1973), 481--505]. We can find each pattern +$p_1\ldots p_k$ by letting $z_0$ be one greater than the relevant language +index and then, for |1 <= i <= k|, +setting |@t$z\_i$@>=trie_link@t$(z\_{i-1})+p\_i$@>|; the pattern will be +identified by the number $z_k$. Since all the pattern information is +packed together into a single |trie_link| array, it is necessary to +prevent confusion between the data from inequivalent patterns, so another +table is provided such that |trie_char@t$(z\_i)=p\_i$@>| for all |i|. There +is also a table |trie_op|$(z_k)$ to identify the numbers $n_0\ldots n_k$ +associated with $p_1\ldots p_k$. + +Comparatively few different number sequences $n_0\ldots n_k$ actually occur, +since most of the |n|'s are generally zero. Therefore the number sequences +are encoded in such a way that |trie_op|$(z_k)$ is only one byte long. +If |trie_op(@t$z\_k$@>)!=min_quarterword|, when $p_1\ldots p_k$ has matched +the letters in |hc[(l-k+1)dotdot l@,]| of language |t|, +we perform all of the required operations +for this pattern by carrying out the following little program: Set +|v=trie_op(@t$z\_k$@>)|. Then set |v=v+op_start[t]|, +|hyf[l-hyf_distance[v]]=@tmax@>(hyf[l-hyf_distance[v]], hyf_num[v])|, +and |v=hyf_next[v]|; repeat, if necessary, until |v==min_quarterword|. + +@<Types...@>= +typedef int32_t trie_pointer; /*an index into |trie|*/ + +@ @d trie_link(A) trie[A].rh /*``downward'' link in a trie*/ +@d trie_char(A) trie[A].b1 /*character matched at this trie location*/ +@d trie_op(A) trie[A].b0 /*program for hyphenation at this trie location*/ + +@<Glob...@>= +static two_halves @!trie[trie_size+1]; /*|trie_link|, |trie_char|, |trie_op|*/ +static small_number @!hyf_distance0[trie_op_size], *const @!hyf_distance = @!hyf_distance0-1; /*position |k-j| of $n_j$*/ +static small_number @!hyf_num0[trie_op_size], *const @!hyf_num = @!hyf_num0-1; /*value of $n_j$*/ +static quarterword @!hyf_next0[trie_op_size], *const @!hyf_next = @!hyf_next0-1; /*continuation code*/ +static uint16_t @!op_start[256]; /*offset for current language*/ + +@ @<Local variables for hyph...@>= +trie_pointer @!z; /*an index into |trie|*/ +int @!v; /*an index into |hyf_distance|, etc.*/ + +@ Assuming that these auxiliary tables have been set up properly, the +hyphenation algorithm is quite short. In the following code we set |hc[hn+2]| +to the impossible value 256, in order to guarantee that |hc[hn+3]| will +never be fetched. + +@<Find hyphen locations for the word in |hc|...@>= +for (j=0; j<=hn; j++) hyf[j]=0; +@<Look for the word |hc[1..hn]| in the exception table, and |goto found| (with |hyf| +containing the hyphens) if an entry is found@>; +if (trie_char(cur_lang+1)!=qi(cur_lang)) return; /*no patterns for |cur_lang|*/ +hc[0]=0;hc[hn+1]=0;hc[hn+2]=256; /*insert delimiters*/ +for (j=0; j<=hn-r_hyf+1; j++) + {@+z=trie_link(cur_lang+1)+hc[j];l=j; + while (hc[l]==qo(trie_char(z))) + {@+if (trie_op(z)!=min_quarterword) + @<Store \(m)maximum values in the |hyf| table@>; + incr(l);z=trie_link(z)+hc[l]; + } + } +found: for (j=0; j<=l_hyf-1; j++) hyf[j]=0; +for (j=0; j<=r_hyf-1; j++) hyf[hn-j]=0 + +@ @<Store \(m)maximum values in the |hyf| table@>= +{@+v=trie_op(z); +@/do@+{v=v+op_start[cur_lang];i=l-hyf_distance[v]; +if (hyf_num[v] > hyf[i]) hyf[i]=hyf_num[v]; +v=hyf_next[v]; +}@+ while (!(v==min_quarterword)); +} + +@ The exception table that is built by \TeX's \.{\\hyphenation} primitive is +organized as an ordered hash table [cf.\ Amble and Knuth, {\sl The Computer +@^Amble, Ole@> @^Knuth, Donald Ervin@> +Journal\/ \bf17} (1974), 135--142] using linear probing. If $\alpha$ and +$\beta$ are words, we will say that $\alpha<\beta$ if $\vert\alpha\vert< +\vert\beta\vert$ or if $\vert\alpha\vert=\vert\beta\vert$ and +$\alpha$ is lexicographically smaller than $\beta$. (The notation $\vert +\alpha\vert$ stands for the length of $\alpha$.) The idea of ordered hashing +is to arrange the table so that a given word $\alpha$ can be sought by computing +a hash address $h=h(\alpha)$ and then looking in table positions |h|, |h-1|, +\dots, until encountering the first word $\le\alpha$. If this word is +different from $\alpha$, we can conclude that $\alpha$ is not in the table. + +The words in the table point to lists in |mem| that specify hyphen positions +in their |info| fields. The list for $c_1\ldots c_n$ contains the number |k| if +the word $c_1\ldots c_n$ has a discretionary hyphen between $c_k$ and +$c_{k+1}$. + +@<Types...@>= +typedef int16_t hyph_pointer; /*an index into the ordered hash table*/ + +@ @<Glob...@>= +static str_number @!hyph_word[hyph_size+1]; /*exception words*/ +static pointer @!hyph_list[hyph_size+1]; /*lists of hyphen positions*/ +static hyph_pointer @!hyph_count; /*the number of words in the exception dictionary*/ + +@ @<Local variables for init...@>= +int @!z; /*runs through the exception dictionary*/ + +@ @<Set init...@>= +for (z=0; z<=hyph_size; z++) + {@+hyph_word[z]=0;hyph_list[z]=null; + } +hyph_count=0; + +@ The algorithm for exception lookup is quite simple, as soon as we have +a few more local variables to work with. + +@<Local variables for hyph...@>= +hyph_pointer @!h; /*an index into |hyph_word| and |hyph_list|*/ +str_number @!k; /*an index into |str_start|*/ +pool_pointer @!u; /*an index into |str_pool|*/ + +@ First we compute the hash code |h|, then we search until we either +find the word or we don't. Words from different languages are kept +separate by appending the language code to the string. + +@<Look for the word |hc[1...@>= +h=hc[1];incr(hn);hc[hn]=cur_lang; +for (j=2; j<=hn; j++) h=(h+h+hc[j])%hyph_size; +loop@+{@+@<If the string |hyph_word[h]| is less than \(hc)|hc[1..hn]|, |goto not_found|; +but if the two strings are equal, set |hyf| to the hyphen positions and |goto found|@>; + if (h > 0) decr(h);@+else h=hyph_size; + } +not_found: decr(hn) + +@ @<If the string |hyph_word[h]| is less than \(hc)...@>= +k=hyph_word[h];if (k==0) goto not_found; +if (length(k) < hn) goto not_found; +if (length(k)==hn) + {@+j=1;u=str_start[k]; + @/do@+{if (so(str_pool[u]) < hc[j]) goto not_found; + if (so(str_pool[u]) > hc[j]) goto done; + incr(j);incr(u); + }@+ while (!(j > hn)); + @<Insert hyphens as specified in |hyph_list[h]|@>; + decr(hn);goto found; + } +done: + +@ @<Insert hyphens as specified...@>= +s=hyph_list[h]; +while (s!=null) + {@+hyf[info(s)]=1;s=link(s); + } + +@ @<Search |hyph_list| for pointers to |p|@>= +for (q=0; q<=hyph_size; q++) + {@+if (hyph_list[q]==p) + {@+print_nl("HYPH(");print_int(q);print_char(')'); + } + } + +@ We have now completed the hyphenation routine, so the |line_break| procedure +is finished at last. Since the hyphenation exception table is fresh in our +minds, it's a good time to deal with the routine that adds new entries to it. + +When \TeX\ has scanned `\.{\\hyphenation}', it calls on a procedure named +|new_hyph_exceptions| to do the right thing. + +@d set_cur_lang if (language <= 0) cur_lang=0; + else if (language > 255) cur_lang=0; + else cur_lang=language + +@p static void new_hyph_exceptions(void) /*enters new exceptions*/ +{@+ +int n; /*length of current word; not always a |small_number|*/ +int @!j; /*an index into |hc|*/ +hyph_pointer @!h; /*an index into |hyph_word| and |hyph_list|*/ +str_number @!k; /*an index into |str_start|*/ +pointer @!p; /*head of a list of hyphen positions*/ +pointer @!q; /*used when creating a new node for list |p|*/ +str_number @!s, @!t; /*strings being compared or stored*/ +pool_pointer @!u, @!v; /*indices into |str_pool|*/ +scan_left_brace(); /*a left brace must follow \.{\\hyphenation}*/ +set_cur_lang; +@<Enter as many hyphenation exceptions as are listed, until coming to a right brace; +then |return|@>; +} + +@ @<Enter as many...@>= +n=0;p=null; +loop@+{@+get_x_token(); + reswitch: switch (cur_cmd) { + case letter: case other_char: case char_given: @<Append a new letter or hyphen@>@;@+break; + case char_num: {@+scan_char_num();cur_chr=cur_val;cur_cmd=char_given; + goto reswitch; + } + case spacer: case right_brace: {@+if (n > 1) @<Enter a hyphenation exception@>; + if (cur_cmd==right_brace) return; + n=0;p=null; + } @+break; + default:@<Give improper \.{\\hyphenation} error@>@; + } + } + +@ @<Give improper \.{\\hyph...@>= +{@+print_err("Improper ");print_esc("hyphenation"); +@.Improper \\hyphenation...@> + print(" will be flushed"); +help2("Hyphenation exceptions must contain only letters",@/ + "and hyphens. But continue; I'll forgive and forget."); +error(); +} + +@ @<Append a new letter or hyphen@>= +if (cur_chr=='-') @<Append the value |n| to list |p|@>@; +else{@+if (lc_code(cur_chr)==0) + {@+print_err("Not a letter"); +@.Not a letter@> + help2("Letters in \\hyphenation words must have \\lccode>0.",@/ + "Proceed; I'll ignore the character I just read."); + error(); + } + else if (n < 63) + {@+incr(n);hc[n]=lc_code(cur_chr); + } + } + +@ @<Append the value |n| to list |p|@>= +{@+if (n < 63) + {@+q=get_avail();link(q)=p;info(q)=n;p=q; + } +} + +@ @<Enter a hyphenation exception@>= +{@+incr(n);hc[n]=cur_lang;str_room(n);h=0; +for (j=1; j<=n; j++) + {@+h=(h+h+hc[j])%hyph_size; + append_char(hc[j]); + } +s=make_string(); +@<Insert the \(p)pair |(s,p)| into the exception table@>; +} + +@ @<Insert the \(p)pair |(s,p)|...@>= +if (hyph_count==hyph_size) overflow("exception dictionary", hyph_size); +@:TeX capacity exceeded exception dictionary}{\quad exception dictionary@> +incr(hyph_count); +while (hyph_word[h]!=0) + {@+@<If the string |hyph_word[h]| is less than \(or)or equal to |s|, interchange +|(hyph_word[h],hyph_list[h])| with |(s,p)|@>; + if (h > 0) decr(h);@+else h=hyph_size; + } +hyph_word[h]=s;hyph_list[h]=p + +@ @<If the string |hyph_word[h]| is less than \(or)...@>= +k=hyph_word[h]; +if (length(k) < length(s)) goto found; +if (length(k) > length(s)) goto not_found; +u=str_start[k];v=str_start[s]; +@/do@+{if (str_pool[u] < str_pool[v]) goto found; +if (str_pool[u] > str_pool[v]) goto not_found; +incr(u);incr(v); +}@+ while (!(u==str_start[k+1])); +found: q=hyph_list[h];hyph_list[h]=p;p=q;@/ +t=hyph_word[h];hyph_word[h]=s;s=t; +not_found: + +@* Initializing the hyphenation tables. +The trie for \TeX's hyphenation algorithm is built from a sequence of +patterns following a \.{\\patterns} specification. Such a specification +is allowed only in \.{INITEX}, since the extra memory for auxiliary tables +and for the initialization program itself would only clutter up the +production version of \TeX\ with a lot of deadwood. + +The first step is to build a trie that is linked, instead of packed +into sequential storage, so that insertions are readily made. +After all patterns have been processed, \.{INITEX} +compresses the linked trie by identifying common subtries. Finally the +trie is packed into the efficient sequential form that the hyphenation +algorithm actually uses. + +@<Declare subprocedures for |line_break|@>= +#ifdef @!INIT +@<Declare procedures for preprocessing hyphenation patterns@>@; +#endif + +@ Before we discuss trie building in detail, let's consider the simpler +problem of creating the |hyf_distance|, |hyf_num|, and |hyf_next| arrays. + +Suppose, for example, that \TeX\ reads the pattern `\.{ab2cde1}'. This is +a pattern of length 5, with $n_0\ldots n_5=0\,0\,2\,0\,0\,1$ in the +notation above. We want the corresponding |trie_op| code |v| to have +|hyf_distance[v]==3|, |hyf_num[v]==2|, and |hyf_next[v]==@t$v^\prime$@>|, +where the auxiliary |trie_op| code $v^\prime$ has +|hyf_distance[@t$v^\prime$@>]==0|, |hyf_num[@t$v^\prime$@>]==1|, and +|hyf_next[@t$v^\prime$@>]==min_quarterword|. + +\TeX\ computes an appropriate value |v| with the |new_trie_op| subroutine +below, by setting +$$\hbox{|@t$v^\prime$@>=new_trie_op(0, 1, min_quarterword)|,\qquad +|v=new_trie_op(3, 2,@t$v^\prime$@>)|.}$$ +This subroutine looks up its three +parameters in a special hash table, assigning a new value only if these +three have not appeared before for the current language. + +The hash table is called |trie_op_hash|, and the number of entries it contains +is |trie_op_ptr|. + +@<Glob...@>= +#ifdef @!INIT +static uint16_t @!trie_op_hash0[trie_op_size+trie_op_size+1], *const @!trie_op_hash = @!trie_op_hash0+trie_op_size; + /*trie op codes for quadruples*/ +static quarterword @!trie_used[256]; + /*largest opcode used so far for this language*/ +static ASCII_code @!trie_op_lang0[trie_op_size], *const @!trie_op_lang = @!trie_op_lang0-1; + /*language part of a hashed quadruple*/ +static quarterword @!trie_op_val0[trie_op_size], *const @!trie_op_val = @!trie_op_val0-1; + /*opcode corresponding to a hashed quadruple*/ +static int @!trie_op_ptr; /*number of stored ops so far*/ +#endif + +@ It's tempting to remove the |overflow| stops in the following procedure; +|new_trie_op| could return |min_quarterword| (thereby simply ignoring +part of a hyphenation pattern) instead of aborting the job. However, that would +lead to different hyphenation results on different installations of \TeX\ +using the same patterns. The |overflow| stops are necessary for portability +of patterns. + +@<Declare procedures for preprocessing hyph...@>= +static quarterword new_trie_op(small_number @!d, small_number @!n, quarterword @!v) +{@+ +int h; /*trial hash location*/ +quarterword @!u; /*trial op code*/ +int @!l; /*pointer to stored data*/ +h=abs(n+313*d+361*v+1009*cur_lang)%(trie_op_size+trie_op_size) + -trie_op_size; +loop@+{@+l=trie_op_hash[h]; + if (l==0) /*empty position found for a new op*/ + {@+if (trie_op_ptr==trie_op_size) + overflow("pattern memory ops", trie_op_size); + u=trie_used[cur_lang]; + if (u==max_quarterword) + overflow("pattern memory ops per language", + max_quarterword-min_quarterword); + incr(trie_op_ptr);incr(u);trie_used[cur_lang]=u; + hyf_distance[trie_op_ptr]=d; + hyf_num[trie_op_ptr]=n;hyf_next[trie_op_ptr]=v; + trie_op_lang[trie_op_ptr]=cur_lang;trie_op_hash[h]=trie_op_ptr; + trie_op_val[trie_op_ptr]=u;return u; + } + if ((hyf_distance[l]==d)&&(hyf_num[l]==n)&&(hyf_next[l]==v) + &&(trie_op_lang[l]==cur_lang)) + {@+return trie_op_val[l]; + } + if (h > -trie_op_size) decr(h);@+else h=trie_op_size; + } +} + +@ After |new_trie_op| has compressed the necessary opcode information, +plenty of information is available to unscramble the data into the +final form needed by our hyphenation algorithm. + +@<Sort \(t)the hyphenation op tables into proper order@>= +op_start[0]=-min_quarterword; +for (j=1; j<=255; j++) op_start[j]=op_start[j-1]+qo(trie_used[j-1]); +for (j=1; j<=trie_op_ptr; j++) + trie_op_hash[j]=op_start[trie_op_lang[j]]+trie_op_val[j]; /*destination*/ +for (j=1; j<=trie_op_ptr; j++) while (trie_op_hash[j] > j) + {@+k=trie_op_hash[j];@/ + t=hyf_distance[k];hyf_distance[k]=hyf_distance[j];hyf_distance[j]=t;@/ + t=hyf_num[k];hyf_num[k]=hyf_num[j];hyf_num[j]=t;@/ + t=hyf_next[k];hyf_next[k]=hyf_next[j];hyf_next[j]=t;@/ + trie_op_hash[j]=trie_op_hash[k];trie_op_hash[k]=k; + } + +@ Before we forget how to initialize the data structures that have been +mentioned so far, let's write down the code that gets them started. + +@<Initialize table entries...@>= +for (k=-trie_op_size; k<=trie_op_size; k++) trie_op_hash[k]=0; +for (k=0; k<=255; k++) trie_used[k]=min_quarterword; +trie_op_ptr=0; + +@ The linked trie that is used to preprocess hyphenation patterns appears +in several global arrays. Each node represents an instruction of the form +``if you see character |c|, then perform operation |o|, move to the +next character, and go to node |l|; otherwise go to node |r|.'' +The four quantities |c|, |o|, |l|, and |r| are stored in four arrays +|trie_c|, |trie_o|, |trie_l|, and |trie_r|. The root of the trie +is |trie_l[0]|, and the number of nodes is |trie_ptr|. Null trie +pointers are represented by zero. To initialize the trie, we simply +set |trie_l[0]| and |trie_ptr| to zero. We also set |trie_c[0]| to some +arbitrary value, since the algorithm may access it. + +The algorithms maintain the condition +$$\hbox{|trie_c[trie_r[z]] > trie_c[z]|\qquad +whenever |z!=0| and |trie_r[z]!=0|};$$ in other words, sibling nodes are +ordered by their |c| fields. + +@d trie_root trie_l[0] /*root of the linked trie*/ + +@<Glob...@>= +#ifdef @!INIT +static packed_ASCII_code @!trie_c[trie_size+1]; + /*characters to match*/ +@t\hskip10pt@>static quarterword @!trie_o[trie_size+1]; + /*operations to perform*/ +@t\hskip10pt@>static trie_pointer @!trie_l[trie_size+1]; + /*left subtrie links*/ +@t\hskip10pt@>static trie_pointer @!trie_r[trie_size+1]; + /*right subtrie links*/ +@t\hskip10pt@>static trie_pointer @!trie_ptr; /*the number of nodes in the trie*/ +@t\hskip10pt@>static trie_pointer @!trie_hash[trie_size+1]; + /*used to identify equivalent subtries*/ +#endif + +@ Let us suppose that a linked trie has already been constructed. +Experience shows that we can often reduce its size by recognizing common +subtries; therefore another hash table is introduced for this purpose, +somewhat similar to |trie_op_hash|. The new hash table will be +initialized to zero. + +The function |trie_node(p)| returns |p| if |p| is distinct from other nodes +that it has seen, otherwise it returns the number of the first equivalent +node that it has seen. + +Notice that we might make subtries equivalent even if they correspond to +patterns for different languages, in which the trie ops might mean quite +different things. That's perfectly all right. + +@<Declare procedures for preprocessing hyph...@>= +static trie_pointer trie_node(trie_pointer @!p) /*converts + to a canonical form*/ +{@+ +trie_pointer h; /*trial hash location*/ +trie_pointer @!q; /*trial trie node*/ +h=abs(trie_c[p]+1009*trie_o[p]+@| + 2718*trie_l[p]+3142*trie_r[p])%trie_size; +loop@+{@+q=trie_hash[h]; + if (q==0) + {@+trie_hash[h]=p;return p; + } + if ((trie_c[q]==trie_c[p])&&(trie_o[q]==trie_o[p])&&@| + (trie_l[q]==trie_l[p])&&(trie_r[q]==trie_r[p])) + {@+return q; + } + if (h > 0) decr(h);@+else h=trie_size; + } +} + +@ A neat recursive procedure is now able to compress a trie by +traversing it and applying |trie_node| to its nodes in ``bottom up'' +fashion. We will compress the entire trie by clearing |trie_hash| to +zero and then saying `|trie_root=compress_trie(trie_root)|'. +@^recursion@> + +@<Declare procedures for preprocessing hyph...@>= +static trie_pointer compress_trie(trie_pointer @!p) +{@+if (p==0) return 0; +else{@+trie_l[p]=compress_trie(trie_l[p]); + trie_r[p]=compress_trie(trie_r[p]); + return trie_node(p); + } +} + +@ The compressed trie will be packed into the |trie| array using a +``top-down first-fit'' procedure. This is a little tricky, so the reader +should pay close attention: The |trie_hash| array is cleared to zero +again and renamed |trie_ref| for this phase of the operation; later on, +|trie_ref[p]| will be nonzero only if the linked trie node |p| is the +smallest character +in a family and if the characters |c| of that family have been allocated to +locations |trie_ref[p]+c| in the |trie| array. Locations of |trie| that +are in use will have |trie_link==0|, while the unused holes in |trie| +will be doubly linked with |trie_link| pointing to the next larger vacant +location and |trie_back| pointing to the next smaller one. This double +linking will have been carried out only as far as |trie_max|, where +|trie_max| is the largest index of |trie| that will be needed. +To save time at the low end of the trie, we maintain array entries +|trie_min[c]| pointing to the smallest hole that is greater than~|c|. +Another array |trie_taken| tells whether or not a given location is +equal to |trie_ref[p]| for some |p|; this array is used to ensure that +distinct nodes in the compressed trie will have distinct |trie_ref| +entries. + +@d trie_ref trie_hash /*where linked trie families go into |trie|*/ +@d trie_back(A) trie[A].lh /*backward links in |trie| holes*/ + +@<Glob...@>= +#ifdef @!INIT +static bool @!trie_taken0[trie_size], *const @!trie_taken = @!trie_taken0-1; + /*does a family start here?*/ +@t\hskip10pt@>static trie_pointer @!trie_min[256]; + /*the first possible slot for each character*/ +@t\hskip10pt@>static trie_pointer @!trie_max; /*largest location used in |trie|*/ +@t\hskip10pt@>bool @!trie_not_ready; /*is the trie still in linked form?*/ +#endif + +@ Each time \.{\\patterns} appears, it contributes further patterns to +the future trie, which will be built only when hyphenation is attempted or +when a format file is dumped. The boolean variable |trie_not_ready| +will change to |false| when the trie is compressed; this will disable +further patterns. + +@<Initialize table entries...@>= +trie_not_ready=true;trie_root=0;trie_c[0]=si(0);trie_ptr=0; + +@ Here is how the trie-compression data structures are initialized. +If storage is tight, it would be possible to overlap |trie_op_hash|, +|trie_op_lang|, and |trie_op_val| with |trie|, |trie_hash|, and |trie_taken|, +because we finish with the former just before we need the latter. + +@<Get ready to compress the trie@>= +@<Sort \(t)the hyphenation...@>; +for (p=0; p<=trie_size; p++) trie_hash[p]=0; +trie_root=compress_trie(trie_root); /*identify equivalent subtries*/ +for (p=0; p<=trie_ptr; p++) trie_ref[p]=0; +for (p=0; p<=255; p++) trie_min[p]=p+1; +trie_link(0)=1;trie_max=0 + +@ The |first_fit| procedure finds the smallest hole |z| in |trie| such that +a trie family starting at a given node |p| will fit into vacant positions +starting at |z|. If |c==trie_c[p]|, this means that location |z-c| must +not already be taken by some other family, and that |z-c+@t$c^\prime$@>| +must be vacant for all characters $c^\prime$ in the family. The procedure +sets |trie_ref[p]| to |z-c| when the first fit has been found. + +@<Declare procedures for preprocessing hyph...@>= +static void first_fit(trie_pointer @!p) /*packs a family into |trie|*/ +{@+ +trie_pointer h; /*candidate for |trie_ref[p]|*/ +trie_pointer @!z; /*runs through holes*/ +trie_pointer @!q; /*runs through the family starting at |p|*/ +ASCII_code @!c; /*smallest character in the family*/ +trie_pointer @!l, @!r; /*left and right neighbors*/ +int @!ll; /*upper limit of |trie_min| updating*/ +c=so(trie_c[p]); +z=trie_min[c]; /*get the first conceivably good hole*/ +loop@+{@+h=z-c;@/ + @<Ensure that |trie_max>=h+256|@>; + if (trie_taken[h]) goto not_found; + @<If all characters of the family fit relative to |h|, then |goto found|,\30\ otherwise +|goto not_found|@>; + not_found: z=trie_link(z); /*move to the next hole*/ + } +found: @<Pack the family into |trie| relative to |h|@>; +} + +@ By making sure that |trie_max| is at least |h+256|, we can be sure that +|trie_max > z|, since |h==z-c|. It follows that location |trie_max| will +never be occupied in |trie|, and we will have |trie_max >= trie_link(z)|. + +@<Ensure that |trie_max>=h+256|@>= +if (trie_max < h+256) + {@+if (trie_size <= h+256) overflow("pattern memory", trie_size); +@:TeX capacity exceeded pattern memory}{\quad pattern memory@> + @/do@+{incr(trie_max);trie_taken[trie_max]=false; + trie_link(trie_max)=trie_max+1;trie_back(trie_max)=trie_max-1; + }@+ while (!(trie_max==h+256)); + } + +@ @<If all characters of the family fit relative to |h|...@>= +q=trie_r[p]; +while (q > 0) + {@+if (trie_link(h+so(trie_c[q]))==0) goto not_found; + q=trie_r[q]; + } +goto found + +@ @<Pack the family into |trie| relative to |h|@>= +trie_taken[h]=true;trie_ref[p]=h;q=p; +@/do@+{z=h+so(trie_c[q]);l=trie_back(z);r=trie_link(z); +trie_back(r)=l;trie_link(l)=r;trie_link(z)=0; +if (l < 256) + {@+if (z < 256) ll=z;@+else ll=256; + @/do@+{trie_min[l]=r;incr(l); + }@+ while (!(l==ll)); + } +q=trie_r[q]; +}@+ while (!(q==0)) + +@ To pack the entire linked trie, we use the following recursive procedure. +@^recursion@> + +@<Declare procedures for preprocessing hyph...@>= +static void trie_pack(trie_pointer @!p) /*pack subtries of a family*/ +{@+trie_pointer q; /*a local variable that need not be saved on recursive calls*/ +@/do@+{q=trie_l[p]; +if ((q > 0)&&(trie_ref[q]==0)) + {@+first_fit(q);trie_pack(q); + } +p=trie_r[p]; +}@+ while (!(p==0)); +} + +@ When the whole trie has been allocated into the sequential table, we +must go through it once again so that |trie| contains the correct +information. Null pointers in the linked trie will be represented by the +value~0, which properly implements an ``empty'' family. + +@<Move the data into |trie|@>= +h.rh=0;h.b0=min_quarterword;h.b1=min_quarterword; /*|trie_link=0|, + |trie_op=min_quarterword|, |trie_char=qi(0)|*/ +if (trie_root==0) /*no patterns were given*/ + {@+for (r=0; r<=256; r++) trie[r]=h; + trie_max=256; + } +else{@+trie_fix(trie_root); /*this fixes the non-holes in |trie|*/ + r=0; /*now we will zero out all the holes*/ + @/do@+{s=trie_link(r);trie[r]=h;r=s; + }@+ while (!(r > trie_max)); + } +trie_char(0)=qi('?'); /*make |trie_char(c)!=c| for all |c|*/ + +@ The fixing-up procedure is, of course, recursive. Since the linked trie +usually has overlapping subtries, the same data may be moved several +times; but that causes no harm, and at most as much work is done as it +took to build the uncompressed trie. +@^recursion@> + +@<Declare procedures for preprocessing hyph...@>= +static void trie_fix(trie_pointer @!p) /*moves |p| and its siblings into |trie|*/ +{@+trie_pointer q; /*a local variable that need not be saved on recursive calls*/ +ASCII_code @!c; /*another one that need not be saved*/ +trie_pointer @!z; /*|trie| reference; this local variable must be saved*/ +z=trie_ref[p]; +@/do@+{q=trie_l[p];c=so(trie_c[p]); +trie_link(z+c)=trie_ref[q];trie_char(z+c)=qi(c);trie_op(z+c)=trie_o[p]; +if (q > 0) trie_fix(q); +p=trie_r[p]; +}@+ while (!(p==0)); +} + +@ Now let's go back to the easier problem, of building the linked +trie. When \.{INITEX} has scanned the `\.{\\patterns}' control +sequence, it calls on |new_patterns| to do the right thing. + +@<Declare procedures for preprocessing hyph...@>= +static void new_patterns(void) /*initializes the hyphenation pattern data*/ +{@+ +int k, @!l; /*indices into |hc| and |hyf|; + not always in |small_number| range*/ +bool @!digit_sensed; /*should the next digit be treated as a letter?*/ +quarterword @!v; /*trie op code*/ +trie_pointer @!p, @!q; /*nodes of trie traversed during insertion*/ +bool @!first_child; /*is |p==trie_l[q]|?*/ +ASCII_code @!c; /*character being inserted*/ +if (trie_not_ready) + {@+set_cur_lang;scan_left_brace(); /*a left brace must follow \.{\\patterns}*/ + @<Enter all of the patterns into a linked trie, until coming to a right brace@>; + } +else{@+print_err("Too late for ");print_esc("patterns"); + help1("All patterns must be given before typesetting begins."); + error();link(garbage)=scan_toks(false, false);flush_list(def_ref); + } +} + +@ Novices are not supposed to be using \.{\\patterns}, so the error +messages are terse. (Note that all error messages appear in \TeX's string +pool, even if they are used only by \.{INITEX}.) + +@<Enter all of the patterns into a linked trie...@>= +k=0;hyf[0]=0;digit_sensed=false; +loop@+{@+get_x_token(); + switch (cur_cmd) { + case letter: case other_char: @<Append a new letter or a hyphen level@>@;@+break; + case spacer: case right_brace: {@+if (k > 0) + @<Insert a new pattern into the linked trie@>; + if (cur_cmd==right_brace) goto done; + k=0;hyf[0]=0;digit_sensed=false; + } @+break; + default:{@+print_err("Bad ");print_esc("patterns"); +@.Bad \\patterns@> + help1("(See Appendix H.)");error(); + } + } + } +done: + +@ @<Append a new letter or a hyphen level@>= +if (digit_sensed||(cur_chr < '0')||(cur_chr > '9')) + {@+if (cur_chr=='.') cur_chr=0; /*edge-of-word delimiter*/ + else{@+cur_chr=lc_code(cur_chr); + if (cur_chr==0) + {@+print_err("Nonletter"); +@.Nonletter@> + help1("(See Appendix H.)");error(); + } + } + if (k < 63) + {@+incr(k);hc[k]=cur_chr;hyf[k]=0;digit_sensed=false; + } + } +else if (k < 63) + {@+hyf[k]=cur_chr-'0';digit_sensed=true; + } + +@ When the following code comes into play, the pattern $p_1\ldots p_k$ +appears in |hc[1 dotdot k]|, and the corresponding sequence of numbers $n_0\ldots +n_k$ appears in |hyf[0 dotdot k]|. + +@<Insert a new pattern into the linked trie@>= +{@+@<Compute the trie op code, |v|, and set |l:=0|@>; +q=0;hc[0]=cur_lang; +while (l <= k) + {@+c=hc[l];incr(l);p=trie_l[q];first_child=true; + while ((p > 0)&&(c > so(trie_c[p]))) + {@+q=p;p=trie_r[q];first_child=false; + } + if ((p==0)||(c < so(trie_c[p]))) + @<Insert a new trie node between |q| and |p|, and make |p| point to it@>; + q=p; /*now node |q| represents $p_1\ldots p_{l-1}$*/ + } +if (trie_o[q]!=min_quarterword) + {@+print_err("Duplicate pattern"); +@.Duplicate pattern@> + help1("(See Appendix H.)");error(); + } +trie_o[q]=v; +} + +@ @<Insert a new trie node between |q| and |p|...@>= +{@+if (trie_ptr==trie_size) overflow("pattern memory", trie_size); +@:TeX capacity exceeded pattern memory}{\quad pattern memory@> +incr(trie_ptr);trie_r[trie_ptr]=p;p=trie_ptr;trie_l[p]=0; +if (first_child) trie_l[q]=p;@+else trie_r[q]=p; +trie_c[p]=si(c);trie_o[p]=min_quarterword; +} + +@ @<Compute the trie op code, |v|...@>= +if (hc[1]==0) hyf[0]=0; +if (hc[k]==0) hyf[k]=0; +l=k;v=min_quarterword; +loop@+{@+if (hyf[l]!=0) v=new_trie_op(k-l, hyf[l], v); + if (l > 0) decr(l);@+else goto done1; + } +done1: + +@ Finally we put everything together: Here is how the trie gets to its +final, efficient form. +The following packing routine is rigged so that the root of the linked +tree gets mapped into location 1 of |trie|, as required by the hyphenation +algorithm. This happens because the first call of |first_fit| will +``take'' location~1. + +@<Declare procedures for preprocessing hyphenation patterns@>= +void init_trie(void) +{@+int @!p; /*pointer for initialization*/ +int @!j, @!k, @!t; /*all-purpose registers for initialization*/ +int @!r, @!s; /*used to clean up the packed |trie|*/ +two_halves @!h; /*template used to zero out |trie|'s holes*/ +@<Get ready to compress the trie@>; +if (trie_root!=0) + {@+first_fit(trie_root);trie_pack(trie_root); + } +@<Move the data into |trie|@>; +trie_not_ready=false; +} + +@* Breaking vertical lists into pages. +The |vsplit| procedure, which implements \TeX's \.{\\vsplit} operation, +is considerably simpler than |line_break| because it doesn't have to +worry about hyphenation, and because its mission is to discover a single +break instead of an optimum sequence of breakpoints. But before we get +into the details of |vsplit|, we need to consider a few more basic things. + +@ A subroutine called |prune_page_top| takes a pointer to a vlist and +returns a pointer to a modified vlist in which all glue, kern, and penalty nodes +have been deleted before the first box or rule node. However, the first +box or rule is actually preceded by a newly created glue node designed so that +the topmost baseline will be at distance |split_top_skip| from the top, +whenever this is possible without backspacing. + +In this routine and those that follow, we make use of the fact that a +vertical list contains no character nodes, hence the |type| field exists +for each node in the list. +@^data structure assumptions@> + +@p static pointer prune_page_top(pointer @!p) /*adjust top after page break*/ +{@+pointer prev_p; /*lags one step behind |p|*/ +pointer @!q; /*temporary variable for list manipulation*/ +prev_p=temp_head;link(temp_head)=p; +while (p!=null) + switch (type(p)) { + case hlist_node: case vlist_node: case rule_node: @<Insert glue for |split_top_skip| +and set~|p:=null|@>@;@+break; + case whatsit_node: case mark_node: case ins_node: {@+prev_p=p;p=link(prev_p); + } @+break; + case glue_node: case kern_node: case penalty_node: {@+q=p;p=link(q);link(q)=null; + link(prev_p)=p;flush_node_list(q); + } @+break; + default:confusion("pruning"); +@:this can't happen pruning}{\quad pruning@> + } +return link(temp_head); +} + +@ @<Insert glue for |split_top_skip|...@>= +{@+q=new_skip_param(split_top_skip_code);link(prev_p)=q;link(q)=p; + /*now |temp_ptr==glue_ptr(q)|*/ +if (width(temp_ptr) > height(p)) width(temp_ptr)=width(temp_ptr)-height(p); +else width(temp_ptr)=0; +p=null; +} + +@ The next subroutine finds the best place to break a given vertical list +so as to obtain a box of height~|h|, with maximum depth~|d|. +A pointer to the beginning of the vertical list is given, +and a pointer to the optimum breakpoint is returned. The list is effectively +followed by a forced break, i.e., a penalty node with the |eject_penalty|; +if the best break occurs at this artificial node, the value |null| is returned. + +An array of six |scaled| distances is used to keep track of the height +from the beginning of the list to the current place, just as in |line_break|. +In fact, we use one of the same arrays, only changing its name to reflect +its new significance. + +@d active_height active_width /*new name for the six distance variables*/ +@d cur_height active_height[1] /*the natural height*/ +@d set_height_zero(A) active_height[A]=0 /*initialize the height to zero*/ +@# +@p static pointer vert_break(pointer @!p, scaled @!h, scaled @!d) + /*finds optimum page break*/ +{@+ +pointer prev_p; /*if |p| is a glue node, |type(prev_p)| determines + whether |p| is a legal breakpoint*/ +pointer @!q, @!r; /*glue specifications*/ +int @!pi; /*penalty value*/ +int @!b; /*badness at a trial breakpoint*/ +int @!least_cost; /*the smallest badness plus penalties found so far*/ +pointer @!best_place; /*the most recent break that leads to |least_cost|*/ +scaled @!prev_dp; /*depth of previous box in the list*/ +small_number @!t; /*|type| of the node following a kern*/ +prev_p=p; /*an initial glue node is not a legal breakpoint*/ +least_cost=awful_bad;do_all_six(set_height_zero);prev_dp=0; +loop@+{@+@<If node |p| is a legal breakpoint, check if this break is the best known, +and |goto done| if |p| is null or if the page-so-far is already too full to accept +more stuff@>; + prev_p=p;p=link(prev_p); + } +done: return best_place; +} + +@ A global variable |best_height_plus_depth| will be set to the natural size +of the box that corresponds to the optimum breakpoint found by |vert_break|. +(This value is used by the insertion-splitting algorithm of the page builder.) + +@<Glob...@>= +static scaled @!best_height_plus_depth; /*height of the best box, without stretching or + shrinking*/ + +@ A subtle point to be noted here is that the maximum depth~|d| might be +negative, so |cur_height| and |prev_dp| might need to be corrected even +after a glue or kern node. + +@<If node |p| is a legal breakpoint, check...@>= +if (p==null) pi=eject_penalty; +else@<Use node |p| to update the current height and depth measurements; if this node +is not a legal breakpoint, |goto not_found| or |update_heights|, otherwise set |pi| +to the associated penalty at the break@>; +@<Check if node |p| is a new champion breakpoint; then \(go)|goto done| if |p| is +a forced break or if the page-so-far is already too full@>; +if ((type(p) < glue_node)||(type(p) > kern_node)) goto not_found; +update_heights: @<Update the current height and depth measurements with respect to +a glue or kern node~|p|@>; +not_found: if (prev_dp > d) + {@+cur_height=cur_height+prev_dp-d; + prev_dp=d; + } + +@ @<Use node |p| to update the current height and depth measurements...@>= +switch (type(p)) { +case hlist_node: case vlist_node: case rule_node: {@+@t@>@;@/ + cur_height=cur_height+prev_dp+height(p);prev_dp=depth(p); + goto not_found; + } +case whatsit_node: @<Process whatsit |p| in |vert_break| loop, |goto not_found|@>; +case glue_node: if (precedes_break(prev_p)) pi=0; + else goto update_heights;@+break; +case kern_node: {@+if (link(p)==null) t=penalty_node; + else t=type(link(p)); + if (t==glue_node) pi=0;@+else goto update_heights; + } @+break; +case penalty_node: pi=penalty(p);@+break; +case mark_node: case ins_node: goto not_found; +default:confusion("vertbreak"); +@:this can't happen vertbreak}{\quad vertbreak@> +} + +@ @d deplorable 100000 /*more than |inf_bad|, but less than |awful_bad|*/ + +@<Check if node |p| is a new champion breakpoint; then \(go)...@>= +if (pi < inf_penalty) + {@+@<Compute the badness, |b|, using |awful_bad| if the box is too full@>; + if (b < awful_bad) + if (pi <= eject_penalty) b=pi; + else if (b < inf_bad) b=b+pi; + else b=deplorable; + if (b <= least_cost) + {@+best_place=p;least_cost=b; + best_height_plus_depth=cur_height+prev_dp; + } + if ((b==awful_bad)||(pi <= eject_penalty)) goto done; + } + +@ @<Compute the badness, |b|, using |awful_bad| if the box is too full@>= +if (cur_height < h) + if ((active_height[3]!=0)||(active_height[4]!=0)|| + (active_height[5]!=0)) b=0; + else b=badness(h-cur_height, active_height[2]); +else if (cur_height-h > active_height[6]) b=awful_bad; +else b=badness(cur_height-h, active_height[6]) + +@ Vertical lists that are subject to the |vert_break| procedure should not +contain infinite shrinkability, since that would permit any amount of +information to ``fit'' on one page. + +@<Update the current height and depth measurements with...@>= +if (type(p)==kern_node) q=p; +else{@+q=glue_ptr(p); + active_height[2+stretch_order(q)]=@| + active_height[2+stretch_order(q)]+stretch(q);@/ + active_height[6]=active_height[6]+shrink(q); + if ((shrink_order(q)!=normal)&&(shrink(q)!=0)) + {@+@t@>@;@/ + print_err("Infinite glue shrinkage found in box being split");@/ +@.Infinite glue shrinkage...@> + help4("The box you are \\vsplitting contains some infinitely",@/ + "shrinkable glue, e.g., `\\vss' or `\\vskip 0pt minus 1fil'.",@/ + "Such glue doesn't belong there; but you can safely proceed,",@/ + "since the offensive shrinkability has been made finite."); + error();r=new_spec(q);shrink_order(r)=normal;delete_glue_ref(q); + glue_ptr(p)=r;q=r; + } + } +cur_height=cur_height+prev_dp+width(q);prev_dp=0 + +@ Now we are ready to consider |vsplit| itself. Most of +its work is accomplished by the two subroutines that we have just considered. + +Given the number of a vlist box |n|, and given a desired page height |h|, +the |vsplit| function finds the best initial segment of the vlist and +returns a box for a page of height~|h|. The remainder of the vlist, if +any, replaces the original box, after removing glue and penalties and +adjusting for |split_top_skip|. Mark nodes in the split-off box are used to +set the values of |split_first_mark| and |split_bot_mark|; we use the +fact that |split_first_mark==null| if and only if |split_bot_mark==null|. + +The original box becomes ``void'' if and only if it has been entirely +extracted. The extracted box is ``void'' if and only if the original +box was void (or if it was, erroneously, an hlist box). + +@p static pointer vsplit(halfword @!n, scaled @!h) + /*extracts a page of height |h| from box |n|*/ +{@+ +pointer v; /*the box to be split*/ +pointer p; /*runs through the vlist*/ +pointer q; /*points to where the break occurs*/ +cur_val=n;fetch_box(v); +if (split_first_mark!=null) + {@+delete_token_ref(split_first_mark);split_first_mark=null; + delete_token_ref(split_bot_mark);split_bot_mark=null; + } +@<Dispense with trivial cases of void or bad boxes@>; +q=vert_break(list_ptr(v), h, split_max_depth); +@<Look at all the marks in nodes before the break, and set the final link to |null| +at the break@>; +q=prune_page_top(q);p=list_ptr(v);list_ptr(v)=null;flush_node_list(v); +if (q!=null) q=vpack(q, natural); +change_box(q); /*the |eq_level| of the box stays the same*/ +return vpackage(p, h, 0, 0, exactly, split_max_depth); +} + +@ @<Dispense with trivial cases of void or bad boxes@>= +if (v==null) + {@+return null; + } +if (type(v)!=vlist_node) + {@+print_err("");print_esc("vsplit");print(" needs a "); + print_esc("vbox"); +@:vsplit\_}{\.{\\vsplit needs a \\vbox}@> + help2("The box you are trying to split is an \\hbox.",@/ + "I can't split such a box, so I'll leave it alone."); + error();return null; + } + +@ It's possible that the box begins with a penalty node that is the +``best'' break, so we must be careful to handle this special case correctly. + +@<Look at all the marks...@>= +p=list_ptr(v); +if (p==q) list_ptr(v)=null; +else loop@+{@+if (type(p)==mark_node) + if (split_first_mark==null) + {@+split_first_mark=mark_ptr(p); + split_bot_mark=split_first_mark; + token_ref_count(split_first_mark)=@| + token_ref_count(split_first_mark)+2; + } + else{@+delete_token_ref(split_bot_mark); + split_bot_mark=mark_ptr(p); + add_token_ref(split_bot_mark); + } + if (link(p)==q) + {@+link(p)=null;goto done; + } + p=link(p); + } +done: + +@* The page builder. +When \TeX\ appends new material to its main vlist in vertical mode, it uses +a method something like |vsplit| to decide where a page ends, except that +the calculations are done ``on line'' as new items come in. +The main complication in this process is that insertions must be put +into their boxes and removed from the vlist, in a more-or-less optimum manner. + +We shall use the term ``current page'' for that part of the main vlist that +is being considered as a candidate for being broken off and sent to the +user's output routine. The current page starts at |link(page_head)|, and +it ends at |page_tail|. We have |page_head==page_tail| if this list is empty. +@^current page@> + +Utter chaos would reign if the user kept changing page specifications +while a page is being constructed, so the page builder keeps the pertinent +specifications frozen as soon as the page receives its first box or +insertion. The global variable |page_contents| is |empty| when the +current page contains only mark nodes and content-less whatsit nodes; it +is |inserts_only| if the page contains only insertion nodes in addition to +marks and whatsits. Glue nodes, kern nodes, and penalty nodes are +discarded until a box or rule node appears, at which time |page_contents| +changes to |box_there|. As soon as |page_contents| becomes non-|empty|, +the current |vsize| and |max_depth| are squirreled away into |page_goal| +and |page_max_depth|; the latter values will be used until the page has +been forwarded to the user's output routine. The \.{\\topskip} adjustment +is made when |page_contents| changes to |box_there|. + +Although |page_goal| starts out equal to |vsize|, it is decreased by the +scaled natural height-plus-depth of the insertions considered so far, and by +the \.{\\skip} corrections for those insertions. Therefore it represents +the size into which the non-inserted material should fit, assuming that +all insertions in the current page have been made. + +The global variables |best_page_break| and |least_page_cost| correspond +respectively to the local variables |best_place| and |least_cost| in the +|vert_break| routine that we have already studied; i.e., they record the +location and value of the best place currently known for breaking the +current page. The value of |page_goal| at the time of the best break is +stored in |best_size|. + +@d inserts_only 1 + /*|page_contents| when an insert node has been contributed, but no boxes*/ +@d box_there 2 /*|page_contents| when a box or rule has been contributed*/ + +@<Glob...@>= +static pointer @!page_tail; /*the final node on the current page*/ +int @!page_contents; /*what is on the current page so far?*/ +static scaled @!page_max_depth; /*maximum box depth on page being built*/ +static pointer @!best_page_break; /*break here to get the best page known so far*/ +static int @!least_page_cost; /*the score for this currently best page*/ +static scaled @!best_size; /*its |page_goal|*/ + +@ The page builder has another data structure to keep track of insertions. +This is a list of four-word nodes, starting and ending at |page_ins_head|. +That is, the first element of the list is node |r@t$\_1$@>==link(page_ins_head)|; +node $r_j$ is followed by |r@t$\_{j+1}$@>==link(r@t$\_j$@>)|; and if there are +|n| items we have |r@t$\_{n+1}$@>==page_ins_head|. The |subtype| field of +each node in this list refers to an insertion number; for example, `\.{\\insert +250}' would correspond to a node whose |subtype| is |qi(250)| +(the same as the |subtype| field of the relevant |ins_node|). These |subtype| +fields are in increasing order, and |subtype(page_ins_head)== +qi(255)|, so |page_ins_head| serves as a convenient sentinel +at the end of the list. A record is present for each insertion number that +appears in the current page. + +The |type| field in these nodes distinguishes two possibilities that +might occur as we look ahead before deciding on the optimum page break. +If |type(r)==inserting|, then |height(r)| contains the total of the +height-plus-depth dimensions of the box and all its inserts seen so far. +If |type(r)==split_up|, then no more insertions will be made into this box, +because at least one previous insertion was too big to fit on the current +page; |broken_ptr(r)| points to the node where that insertion will be +split, if \TeX\ decides to split it, |broken_ins(r)| points to the +insertion node that was tentatively split, and |height(r)| includes also the +natural height plus depth of the part that would be split off. + +In both cases, |last_ins_ptr(r)| points to the last |ins_node| +encountered for box |qo(subtype(r))| that would be at least partially +inserted on the next page; and |best_ins_ptr(r)| points to the last +such |ins_node| that should actually be inserted, to get the page with +minimum badness among all page breaks considered so far. We have +|best_ins_ptr(r)==null| if and only if no insertion for this box should +be made to produce this optimum page. + +The data structure definitions here use the fact that the |@!height| field +appears in the fourth word of a box node. +@^data structure assumptions@> + +@d page_ins_node_size 4 /*number of words for a page insertion node*/ +@d inserting 0 /*an insertion class that has not yet overflowed*/ +@d split_up 1 /*an overflowed insertion class*/ +@d broken_ptr(A) link(A+1) + /*an insertion for this class will break here if anywhere*/ +@d broken_ins(A) info(A+1) /*this insertion might break at |broken_ptr|*/ +@d last_ins_ptr(A) link(A+2) /*the most recent insertion for this |subtype|*/ +@d best_ins_ptr(A) info(A+2) /*the optimum most recent insertion*/ + +@<Initialize the special list heads...@>= +subtype(page_ins_head)=qi(255); +type(page_ins_head)=split_up;link(page_ins_head)=page_ins_head; + +@ An array |page_so_far| records the heights and depths of everything +on the current page. This array contains six |scaled| numbers, like the +similar arrays already considered in |line_break| and |vert_break|; and it +also contains |page_goal| and |page_depth|, since these values are +all accessible to the user via |set_page_dimen| commands. The +value of |page_so_far[1]| is also called |page_total|. The stretch +and shrink components of the \.{\\skip} corrections for each insertion are +included in |page_so_far|, but the natural space components of these +corrections are not, since they have been subtracted from |page_goal|. + +The variable |page_depth| records the depth of the current page; it has been +adjusted so that it is at most |page_max_depth|. The variable +|last_glue| points to the glue specification of the most recent node +contributed from the contribution list, if this was a glue node; otherwise +|last_glue==max_halfword|. (If the contribution list is nonempty, +however, the value of |last_glue| is not necessarily accurate.) +The variables |last_penalty|, |last_kern|, and |last_node_type| +are similar. And +finally, |insert_penalties| holds the sum of the penalties associated with +all split and floating insertions. + +@d page_goal page_so_far[0] /*desired height of information on page being built*/ +@d page_total page_so_far[1] /*height of the current page*/ +@d page_shrink page_so_far[6] /*shrinkability of the current page*/ +@d page_depth page_so_far[7] /*depth of the current page*/ + +@<Glob...@>= +scaled @!page_so_far[8]; /*height and glue of the current page*/ +static pointer @!last_glue; /*used to implement \.{\\lastskip}*/ +static int @!last_penalty; /*used to implement \.{\\lastpenalty}*/ +static scaled @!last_kern; /*used to implement \.{\\lastkern}*/ +static int @!last_node_type; /*used to implement \.{\\lastnodetype}*/ +static int @!insert_penalties; /*sum of the penalties for held-over insertions*/ + +@ @<Put each...@>= +primitive("pagegoal", set_page_dimen, 0); +@!@:page\_goal\_}{\.{\\pagegoal} primitive@> +primitive("pagetotal", set_page_dimen, 1); +@!@:page\_total\_}{\.{\\pagetotal} primitive@> +primitive("pagestretch", set_page_dimen, 2); +@!@:page\_stretch\_}{\.{\\pagestretch} primitive@> +primitive("pagefilstretch", set_page_dimen, 3); +@!@:page\_fil\_stretch\_}{\.{\\pagefilstretch} primitive@> +primitive("pagefillstretch", set_page_dimen, 4); +@!@:page\_fill\_stretch\_}{\.{\\pagefillstretch} primitive@> +primitive("pagefilllstretch", set_page_dimen, 5); +@!@:page\_filll\_stretch\_}{\.{\\pagefilllstretch} primitive@> +primitive("pageshrink", set_page_dimen, 6); +@!@:page\_shrink\_}{\.{\\pageshrink} primitive@> +primitive("pagedepth", set_page_dimen, 7); +@!@:page\_depth\_}{\.{\\pagedepth} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case set_page_dimen: switch (chr_code) { +case 0: print_esc("pagegoal");@+break; +case 1: print_esc("pagetotal");@+break; +case 2: print_esc("pagestretch");@+break; +case 3: print_esc("pagefilstretch");@+break; +case 4: print_esc("pagefillstretch");@+break; +case 5: print_esc("pagefilllstretch");@+break; +case 6: print_esc("pageshrink");@+break; +default:print_esc("pagedepth"); +} @+break; + +@ @d print_plus(A, B) if (page_so_far[A]!=0) + {@+print(" plus ");print_scaled(page_so_far[A]);print(B);@+} + +@p static void print_totals(void) +{@+print_scaled(page_total); +print_plus(2,""); +print_plus(3,"fil"); +print_plus(4,"fill"); +print_plus(5,"filll"); +if (page_shrink!=0) + {@+print(" minus ");print_scaled(page_shrink); + } +} + +@ @<Show the status of the current page@>= +if (page_head!=page_tail) + {@+print_nl("### current page:"); + if (output_active) print(" (held over for next output)"); +@.held over for next output@> + show_box(link(page_head)); + if (page_contents > empty) + {@+print_nl("total height ");print_totals(); +@:total\_height}{\.{total height}@> + print_nl(" goal height ");print_scaled(page_goal); +@.goal height@> + r=link(page_ins_head); + while (r!=page_ins_head) + {@+print_ln();print_esc("insert");t=qo(subtype(r)); + print_int(t);print(" adds "); + if (count(t)==1000) t=height(r); + else t=x_over_n(height(r), 1000)*count(t); + print_scaled(t); + if (type(r)==split_up) + {@+q=page_head;t=0; + @/do@+{q=link(q); + if ((type(q)==ins_node)&&(subtype(q)==subtype(r))) incr(t); + }@+ while (!(q==broken_ins(r))); + print(", #");print_int(t);print(" might split"); + } + r=link(r); + } + } + } + +@ Here is a procedure that is called when the |page_contents| is changing +from |empty| to |inserts_only| or |box_there|. + +@d set_page_so_far_zero(A) page_so_far[A]=0 + +@p void freeze_page_specs(small_number @!s) +{@+page_contents=s; +page_goal=vsize;page_max_depth=max_depth; +page_depth=0;do_all_six(set_page_so_far_zero); +least_page_cost=awful_bad; +#ifdef @!STAT +if (tracing_pages > 0) + {@+begin_diagnostic(); + print_nl("%% goal height=");print_scaled(page_goal); +@.goal height@> + print(", max depth=");print_scaled(page_max_depth); + end_diagnostic(false); + } @; +#endif +@;@/ +} + +@ Pages are built by appending nodes to the current list in \TeX's +vertical mode, which is at the outermost level of the semantic nest. This +vlist is split into two parts; the ``current page'' that we have been +talking so much about already, and the ``contribution list'' that receives +new nodes as they are created. The current page contains everything that +the page builder has accounted for in its data structures, as described +above, while the contribution list contains other things that have been +generated by other parts of \TeX\ but have not yet been +seen by the page builder. +The contribution list starts at |link(contrib_head)|, and it ends at the +current node in \TeX's vertical mode. + +When \TeX\ has appended new material in vertical mode, it calls the procedure +|build_page|, which tries to catch up by moving nodes from the contribution +list to the current page. This procedure will succeed in its goal of +emptying the contribution list, unless a page break is discovered, i.e., +unless the current page has grown to the point where the optimum next +page break has been determined. In the latter case, the nodes after the +optimum break will go back onto the contribution list, and control will +effectively pass to the user's output routine. + +We make |type(page_head)==glue_node|, so that an initial glue node on +the current page will not be considered a valid breakpoint. + +@<Initialize the special list...@>= +type(page_head)=glue_node;subtype(page_head)=normal; + +@ The global variable |output_active| is true during the time the +user's output routine is driving \TeX. + +@<Glob...@>= +bool @!output_active; /*are we in the midst of an output routine?*/ + +@ @<Set init...@>= +output_active=false;insert_penalties=0; + +@ The page builder is ready to start a fresh page if we initialize +the following state variables. (However, the page insertion list is initialized +elsewhere.) + +@<Start a new current page@>= +page_contents=empty;page_tail=page_head;link(page_head)=null;@/ +last_glue=max_halfword;last_penalty=0;last_kern=0; +last_node_type=-1; +page_depth=0;page_max_depth=0 + +@ At certain times box 255 is supposed to be void (i.e., |null|), +or an insertion box is supposed to be ready to accept a vertical list. +If not, an error message is printed, and the following subroutine +flushes the unwanted contents, reporting them to the user. + +@p static void box_error(eight_bits @!n) +{@+error();begin_diagnostic(); +print_nl("The following box has been deleted:"); +@.The following...deleted@> +show_box(box(n));end_diagnostic(true); +flush_node_list(box(n));box(n)=null; +} + +@ The following procedure guarantees that a given box register +does not contain an \.{\\hbox}. + +@p static void ensure_vbox(eight_bits @!n) +{@+pointer p; /*the box register contents*/ +p=box(n); +if (p!=null) if (type(p)==hlist_node) + {@+print_err("Insertions can only be added to a vbox"); +@.Insertions can only...@> + help3("Tut tut: You're trying to \\insert into a",@/ + "\\box register that now contains an \\hbox.",@/ + "Proceed, and I'll discard its present contents."); + box_error(n); + } +} + +@ \TeX\ is not always in vertical mode at the time |build_page| +is called; the current mode reflects what \TeX\ should return to, after +the contribution list has been emptied. A call on |build_page| should +be immediately followed by `|goto big_switch|', which is \TeX's central +control point. + +@p +void update_last_values(pointer p) +{@<Update the values of |last_glue|, |last_penalty|, and |last_kern|@>; +} + +@ @d contrib_tail nest[0].tail_field /*tail of the contribution list*/ + +@<Make the contribution list empty...@>= +if (nest_ptr==0) tail=contrib_head; /*vertical mode*/ +else contrib_tail=contrib_head /*other modes*/ + +@ @<Update the values of |last_glue|...@>= +if (last_glue!=max_halfword) delete_glue_ref(last_glue); +last_penalty=0;last_kern=0; +last_node_type=type(p)+1; +if (type(p)==glue_node) + {@+last_glue=glue_ptr(p);add_glue_ref(last_glue); + } +else{@+last_glue=max_halfword; + if (type(p)==penalty_node) last_penalty=penalty(p); + else if (type(p)==kern_node) last_kern=width(p); + } + +@ The code here is an example of a many-way switch into routines that +merge together in different places. Some people call this unstructured +programming, but the author doesn't see much wrong with it, as long as +@^Knuth, Donald Ervin@> +the various labels have a well-understood meaning. + +@<Move node |p| to the current page;...@>= +@<If the current page is empty and node |p| is to be deleted, |goto done1|; otherwise +use node |p| to update the state of the current page; if this node is an insertion, +|goto contribute|; otherwise if this node is not a legal breakpoint, |goto contribute| +or |update_heights|; otherwise set |pi| to the penalty associated with this breakpoint@>; +@<Check if node |p| is a new champion breakpoint; then \(if)if it is time for a page +break, prepare for output, and either fire up the user's output routine and |return| +or ship out the page and |goto done|@>; +if ((type(p) < glue_node)||(type(p) > kern_node)) goto contribute; +update_heights: @<Update the current page measurements with respect to the glue or +kern specified by node~|p|@>; +contribute: @<Make sure that |page_max_depth| is not exceeded@>; +@<Link node |p| into the current page and |goto done|@>; +done1: @<Recycle node |p|@>; +done: + +@ @<Link node |p| into the current page and |goto done|@>= +link(page_tail)=p;page_tail=p; +link(contrib_head)=link(p);link(p)=null;goto done + +@ @<Recycle node |p|@>= +link(contrib_head)=link(p);link(p)=null;flush_node_list(p) + +@ The title of this section is already so long, it seems best to avoid +making it more accurate but still longer, by mentioning the fact that a +kern node at the end of the contribution list will not be contributed until +we know its successor. + +@<If the current page is empty...@>= +switch (type(p)) { +case hlist_node: case vlist_node: case rule_node: if (page_contents < box_there) + @<Initialize the current page, insert the \.{\\topskip} glue ahead of |p|, and +|goto continue|@>@; + else@<Prepare to move a box or rule node to the current page, then |goto contribute|@>@;@+break; +case whatsit_node: @<Prepare to move whatsit |p| to the current page, then |goto contribute|@>; +case glue_node: if (page_contents < box_there) goto done1; + else if (precedes_break(page_tail)) pi=0; + else goto update_heights;@+break; +case kern_node: if (page_contents < box_there) goto done1; + else if (link(p)==null) return; + else if (type(link(p))==glue_node) pi=0; + else goto update_heights;@+break; +case penalty_node: if (page_contents < box_there) goto done1;@+else pi=penalty(p);@+break; +case mark_node: goto contribute; +case ins_node: @<Append an insertion to the current page and |goto contribute|@>@; +default:confusion("page"); +@:this can't happen page}{\quad page@> +} + +@ @<Initialize the current page, insert the \.{\\topskip} glue...@>= +{@+if (page_contents==empty) freeze_page_specs(box_there); +else page_contents=box_there; +q=new_skip_param(top_skip_code); /*now |temp_ptr==glue_ptr(q)|*/ +if (width(temp_ptr) > height(p)) width(temp_ptr)=width(temp_ptr)-height(p); +else width(temp_ptr)=0; +link(q)=p;link(contrib_head)=q;goto resume; +} + +@ @<Prepare to move a box or rule node to the current page...@>= +{@+page_total=page_total+page_depth+height(p); +page_depth=depth(p); +goto contribute; +} + +@ @<Make sure that |page_max_depth| is not exceeded@>= +if (page_depth > page_max_depth) + {@+page_total=@| + page_total+page_depth-page_max_depth;@/ + page_depth=page_max_depth; + } + +@ @<Update the current page measurements with respect to the glue...@>= +if (type(p)==kern_node) q=p; +else{@+q=glue_ptr(p); + page_so_far[2+stretch_order(q)]=@| + page_so_far[2+stretch_order(q)]+stretch(q);@/ + page_shrink=page_shrink+shrink(q); + if ((shrink_order(q)!=normal)&&(shrink(q)!=0)) + {@+@t@>@;@/ + print_err("Infinite glue shrinkage found on current page");@/ +@.Infinite glue shrinkage...@> + help4("The page about to be output contains some infinitely",@/ + "shrinkable glue, e.g., `\\vss' or `\\vskip 0pt minus 1fil'.",@/ + "Such glue doesn't belong there; but you can safely proceed,",@/ + "since the offensive shrinkability has been made finite."); + error(); + r=new_spec(q);shrink_order(r)=normal;delete_glue_ref(q); + glue_ptr(p)=r;q=r; + } + } +page_total=page_total+page_depth+width(q);page_depth=0 + +@ @<Check if node |p| is a new champion breakpoint; then \(if)...@>= +if (pi < inf_penalty) + {@+@<Compute the badness, |b|, of the current page, using |awful_bad| if the box +is too full@>; + if (b < awful_bad) + if (pi <= eject_penalty) c=pi; + else if (b < inf_bad) c=b+pi+insert_penalties; + else c=deplorable; + else c=b; + if (insert_penalties >= 10000) c=awful_bad; +#ifdef @!STAT + if (tracing_pages > 0) @<Display the page break cost@>; +#endif +@;@/ + if (c <= least_page_cost) + {@+best_page_break=p;best_size=page_goal; + least_page_cost=c; + r=link(page_ins_head); + while (r!=page_ins_head) + {@+best_ins_ptr(r)=last_ins_ptr(r); + r=link(r); + } + } + if ((c==awful_bad)||(pi <= eject_penalty)) + {@+fire_up(p); /*output the current page at the best place*/ + if (output_active) return; /*user's output routine will act*/ + goto done; /*the page has been shipped out by default output routine*/ + } + } + +@ @<Display the page break cost@>= +{@+begin_diagnostic();print_nl("%"); +print(" t=");print_totals();@/ +print(" g=");print_scaled(page_goal);@/ +print(" b="); +if (b==awful_bad) print_char('*');@+else print_int(b); +@.*\relax@> +print(" p=");print_int(pi); +print(" c="); +if (c==awful_bad) print_char('*');@+else print_int(c); +if (c <= least_page_cost) print_char('#'); +end_diagnostic(false); +} + +@ @<Compute the badness, |b|, of the current page...@>= +if (page_total < page_goal) + if ((page_so_far[3]!=0)||(page_so_far[4]!=0)||@| + (page_so_far[5]!=0)) b=0; + else b=badness(page_goal-page_total, page_so_far[2]); +else if (page_total-page_goal > page_shrink) b=awful_bad; +else b=badness(page_total-page_goal, page_shrink) + +@ @<Append an insertion to the current page and |goto contribute|@>= +{@+if (page_contents==empty) freeze_page_specs(inserts_only); +n=subtype(p);r=page_ins_head; +while (n >= subtype(link(r))) r=link(r); +n=qo(n); +if (subtype(r)!=qi(n)) + @<Create a page insertion node with |subtype(r)=qi(n)|, and include the glue correction +for box |n| in the current page state@>; +if (type(r)==split_up) insert_penalties=insert_penalties+float_cost(p); +else{@+last_ins_ptr(r)=p; + delta=page_goal-page_total-page_depth+page_shrink; + /*this much room is left if we shrink the maximum*/ + if (count(n)==1000) h=height(p); + else h=x_over_n(height(p), 1000)*count(n); /*this much room is needed*/ + if (((h <= 0)||(h <= delta))&&(height(p)+height(r) <= dimen(n))) + {@+page_goal=page_goal-h;height(r)=height(r)+height(p); + } + else@<Find the best way to split the insertion, and change |type(r)| to |split_up|@>; + } +goto contribute; +} + +@ We take note of the value of \.{\\skip} |n| and the height plus depth +of \.{\\box}~|n| only when the first \.{\\insert}~|n| node is +encountered for a new page. A user who changes the contents of \.{\\box}~|n| +after that first \.{\\insert}~|n| had better be either extremely careful +or extremely lucky, or both. + +@<Create a page insertion node...@>= +{@+q=get_node(page_ins_node_size);link(q)=link(r);link(r)=q;r=q; +subtype(r)=qi(n);type(r)=inserting;ensure_vbox(n); +if (box(n)==null) height(r)=0; +else height(r)=height(box(n))+depth(box(n)); +best_ins_ptr(r)=null;@/ +q=skip(n); +if (count(n)==1000) h=height(r); +else h=x_over_n(height(r), 1000)*count(n); +page_goal=page_goal-h-width(q);@/ +page_so_far[2+stretch_order(q)]=@|page_so_far[2+stretch_order(q)]+stretch(q);@/ +page_shrink=page_shrink+shrink(q); +if ((shrink_order(q)!=normal)&&(shrink(q)!=0)) + {@+print_err("Infinite glue shrinkage inserted from ");print_esc("skip"); +@.Infinite glue shrinkage...@> + print_int(n); + help3("The correction glue for page breaking with insertions",@/ + "must have finite shrinkability. But you may proceed,",@/ + "since the offensive shrinkability has been made finite."); + error(); + } +} + +@ Here is the code that will split a long footnote between pages, in an +emergency. The current situation deserves to be recapitulated: Node |p| +is an insertion into box |n|; the insertion will not fit, in its entirety, +either because it would make the total contents of box |n| greater than +\.{\\dimen} |n|, or because it would make the incremental amount of growth +|h| greater than the available space |delta|, or both. (This amount |h| has +been weighted by the insertion scaling factor, i.e., by \.{\\count} |n| +over 1000.) Now we will choose the best way to break the vlist of the +insertion, using the same criteria as in the \.{\\vsplit} operation. + +@<Find the best way to split the insertion...@>= +{@+if (count(n) <= 0) w=max_dimen; +else{@+w=page_goal-page_total-page_depth; + if (count(n)!=1000) w=x_over_n(w, count(n))*1000; + } +if (w > dimen(n)-height(r)) w=dimen(n)-height(r); +q=vert_break(ins_ptr(p), w, depth(p)); +height(r)=height(r)+best_height_plus_depth; +#ifdef @!STAT +if (tracing_pages > 0) @<Display the insertion split cost@>; +#endif +@;@/ +if (count(n)!=1000) + best_height_plus_depth=x_over_n(best_height_plus_depth, 1000)*count(n); +page_goal=page_goal-best_height_plus_depth; +type(r)=split_up;broken_ptr(r)=q;broken_ins(r)=p; +if (q==null) insert_penalties=insert_penalties+eject_penalty; +else if (type(q)==penalty_node) insert_penalties=insert_penalties+penalty(q); +} + +@ @<Display the insertion split cost@>= +{@+begin_diagnostic();print_nl("% split");print_int(n); +@.split@> +print(" to ");print_scaled(w); +print_char(',');print_scaled(best_height_plus_depth);@/ +print(" p="); +if (q==null) print_int(eject_penalty); +else if (type(q)==penalty_node) print_int(penalty(q)); +else print_char('0'); +end_diagnostic(false); +} + +@ When the page builder has looked at as much material as could appear before +the next page break, it makes its decision. The break that gave minimum +badness will be used to put a completed ``page'' into box 255, with insertions +appended to their other boxes. + +We also set the values of |top_mark|, |first_mark|, and |bot_mark|. The +program uses the fact that |bot_mark!=null| implies |first_mark!=null|; +it also knows that |bot_mark==null| implies |top_mark==first_mark==null|. + +The |fire_up| subroutine prepares to output the current page at the best +place; then it fires up the user's output routine, if there is one, +or it simply ships out the page. There is one parameter, |c|, which represents +the node that was being contributed to the page when the decision to +force an output was made. + +@<Declare the procedure called |fire_up|@>= +static void fire_up(pointer @!c) +{@+ +pointer p, @!q, @!r, @!s; /*nodes being examined and/or changed*/ +pointer @!prev_p; /*predecessor of |p|*/ +int @!n; /*insertion box number*/ +bool @!wait; /*should the present insertion be held over?*/ +int @!save_vbadness; /*saved value of |vbadness|*/ +scaled @!save_vfuzz; /*saved value of |vfuzz|*/ +pointer @!save_split_top_skip; /*saved value of |split_top_skip|*/ +@<Set the value of |output_penalty|@>; +if (bot_mark!=null) + {@+if (top_mark!=null) delete_token_ref(top_mark); + top_mark=bot_mark;add_token_ref(top_mark); + delete_token_ref(first_mark);first_mark=null; + } +@<Put the \(o)optimal current page into box 255, update |first_mark| and |bot_mark|, +append insertions to their boxes, and put the remaining nodes back on the contribution +list@>; +if ((top_mark!=null)&&(first_mark==null)) + {@+first_mark=top_mark;add_token_ref(top_mark); + } +if (output_routine!=null) + if (dead_cycles >= max_dead_cycles) + @<Explain that too many dead cycles have occurred in a row@>@; + else@<Fire up the user's output routine and |return|@>; +@<Perform the default output routine@>; +} + +@ @<Set the value of |output_penalty|@>= +if (type(best_page_break)==penalty_node) + {@+geq_word_define(int_base+output_penalty_code, penalty(best_page_break)); + penalty(best_page_break)=inf_penalty; + } +else geq_word_define(int_base+output_penalty_code, inf_penalty) + +@ As the page is finally being prepared for output, +pointer |p| runs through the vlist, with |prev_p| trailing behind; +pointer |q| is the tail of a list of insertions that +are being held over for a subsequent page. + +@<Put the \(o)optimal current page into box 255...@>= +if (c==best_page_break) best_page_break=null; /*|c| not yet linked in*/ +@<Ensure that box 255 is empty before output@>; +insert_penalties=0; /*this will count the number of insertions held over*/ +save_split_top_skip=split_top_skip; +if (holding_inserts <= 0) + @<Prepare all the boxes involved in insertions to act as queues@>; +q=hold_head;link(q)=null;prev_p=page_head;p=link(prev_p); +while (p!=best_page_break) + {@+if (type(p)==ins_node) + {@+if (holding_inserts <= 0) + @<Either insert the material specified by node |p| into the appropriate box, +or hold it for the next page; also delete node |p| from the current page@>; + } + else if (type(p)==mark_node) @<Update the values of |first_mark| and |bot_mark|@>; + prev_p=p;p=link(prev_p); + } +split_top_skip=save_split_top_skip; +@<Break the current page at node |p|, put it in box~255, and put the remaining nodes +on the contribution list@>; +@<Delete \(t)the page-insertion nodes@>@; + +@ @<Ensure that box 255 is empty before output@>= +if (box(255)!=null) + {@+print_err("");print_esc("box");print("255 is not void"); +@:box255}{\.{\\box255 is not void}@> + help2("You shouldn't use \\box255 except in \\output routines.",@/ + "Proceed, and I'll discard its present contents."); + box_error(255); + } + +@ @<Update the values of |first_mark| and |bot_mark|@>= +{@+if (first_mark==null) + {@+first_mark=mark_ptr(p); + add_token_ref(first_mark); + } +if (bot_mark!=null) delete_token_ref(bot_mark); +bot_mark=mark_ptr(p);add_token_ref(bot_mark); +} + +@ When the following code is executed, the current page runs from node +|link(page_head)| to node |prev_p|, and the nodes from |p| to |page_tail| +are to be placed back at the front of the contribution list. Furthermore +the heldover insertions appear in a list from |link(hold_head)| to |q|; we +will put them into the current page list for safekeeping while the user's +output routine is active. We might have |q==hold_head|; and |p==null| if +and only if |prev_p==page_tail|. Error messages are suppressed within +|vpackage|, since the box might appear to be overfull or underfull simply +because the stretch and shrink from the \.{\\skip} registers for inserts +are not actually present in the box. + +@<Break the current page at node |p|, put it...@>= +if (p!=null) + {@+if (link(contrib_head)==null) + if (nest_ptr==0) tail=page_tail; + else contrib_tail=page_tail; + link(page_tail)=link(contrib_head); + link(contrib_head)=p; + link(prev_p)=null; + } +save_vbadness=vbadness;vbadness=inf_bad; +save_vfuzz=vfuzz;vfuzz=max_dimen; /*inhibit error messages*/ +box(255)=vpackage(link(page_head), best_size, 0, 0, exactly, page_max_depth); +vbadness=save_vbadness;vfuzz=save_vfuzz; +if (last_glue!=max_halfword) delete_glue_ref(last_glue); +@<Start a new current page@>; /*this sets |last_glue=max_halfword|*/ +if (q!=hold_head) + {@+link(page_head)=link(hold_head);page_tail=q; + } + +@ If many insertions are supposed to go into the same box, we want to know +the position of the last node in that box, so that we don't need to waste time +when linking further information into it. The |last_ins_ptr| fields of the +page insertion nodes are therefore used for this purpose during the +packaging phase. + +@<Prepare all the boxes involved in insertions to act as queues@>= +{@+r=link(page_ins_head); +while (r!=page_ins_head) + {@+if (best_ins_ptr(r)!=null) + {@+n=qo(subtype(r));ensure_vbox(n); + if (box(n)==null) box(n)=new_null_box(); + p=box(n)+list_offset; + while (link(p)!=null) p=link(p); + last_ins_ptr(r)=p; + } + r=link(r); + } +} + +@ @<Delete \(t)the page-insertion nodes@>= +r=link(page_ins_head); +while (r!=page_ins_head) + {@+q=link(r);free_node(r, page_ins_node_size);r=q; + } +link(page_ins_head)=page_ins_head + +@ We will set |best_ins_ptr=null| and package the box corresponding to +insertion node~|r|, just after making the final insertion into that box. +If this final insertion is `|split_up|', the remainder after splitting +and pruning (if any) will be carried over to the next page. + +@<Either insert the material specified by node |p| into...@>= +{@+r=link(page_ins_head); +while (subtype(r)!=subtype(p)) r=link(r); +if (best_ins_ptr(r)==null) wait=true; +else{@+wait=false;s=last_ins_ptr(r);link(s)=ins_ptr(p); + if (best_ins_ptr(r)==p) + @<Wrap up the box specified by node |r|, splitting node |p| if called for; set +|wait:=true| if node |p| holds a remainder after splitting@>@; + else{@+while (link(s)!=null) s=link(s); + last_ins_ptr(r)=s; + } + } +@<Either append the insertion node |p| after node |q|, and remove it from the current +page, or delete |node(p)|@>; +} + +@ @<Wrap up the box specified by node |r|, splitting node |p| if...@>= +{@+if (type(r)==split_up) + if ((broken_ins(r)==p)&&(broken_ptr(r)!=null)) + {@+while (link(s)!=broken_ptr(r)) s=link(s); + link(s)=null; + split_top_skip=split_top_ptr(p); + ins_ptr(p)=prune_page_top(broken_ptr(r)); + if (ins_ptr(p)!=null) + {@+temp_ptr=vpack(ins_ptr(p), natural); + height(p)=height(temp_ptr)+depth(temp_ptr); + list_ptr(temp_ptr)=null;flush_node_list(temp_ptr);wait=true; + } + } +best_ins_ptr(r)=null; +n=qo(subtype(r)); +temp_ptr=list_ptr(box(n)); +list_ptr(box(n))=null;flush_node_list(box(n)); +box(n)=vpack(temp_ptr, natural); +} + +@ @<Either append the insertion node |p|...@>= +link(prev_p)=link(p);link(p)=null; +if (wait) + {@+link(q)=p;q=p;incr(insert_penalties); + } +else{@+delete_glue_ref(split_top_ptr(p)); + free_node(p, ins_node_size); + } +p=prev_p + +@ The list of heldover insertions, running from |link(page_head)| to +|page_tail|, must be moved to the contribution list when the user has +specified no output routine. + +@<Perform the default output routine@>= +{@+if (link(page_head)!=null) + {@+if (link(contrib_head)==null) + if (nest_ptr==0) tail=page_tail;@+else contrib_tail=page_tail; + else link(page_tail)=link(contrib_head); + link(contrib_head)=link(page_head); + link(page_head)=null;page_tail=page_head; + } +ship_out(box(255));box(255)=null; +} + +@ @<Explain that too many dead cycles have occurred in a row@>= +{@+print_err("Output loop---");print_int(dead_cycles); +@.Output loop...@> +print(" consecutive dead cycles"); +help3("I've concluded that your \\output is awry; it never does a",@/ +"\\shipout, so I'm shipping \\box255 out myself. Next time",@/ +"increase \\maxdeadcycles if you want me to be more patient!");error(); +} + +@ @<Fire up the user's output routine and |return|@>= +{@+output_active=true; +incr(dead_cycles); +push_nest();mode=-vmode;prev_depth=ignore_depth;mode_line=-line; +begin_token_list(output_routine, output_text); +new_save_level(output_group);normal_paragraph(); +scan_left_brace(); +return; +} + +@ When the user's output routine finishes, it has constructed a vlist +in internal vertical mode, and \TeX\ will do the following: + +@<Resume the page builder after an output routine has come to an end@>= +{@+if ((loc!=null)|| + ((token_type!=output_text)&&(token_type!=backed_up))) + @<Recover from an unbalanced output routine@>; +end_token_list(); /*conserve stack space in case more outputs are triggered*/ +end_graf();unsave();output_active=false;insert_penalties=0;@/ +@<Ensure that box 255 is empty after output@>; +if (tail!=head) /*current list goes after heldover insertions*/ + {@+link(page_tail)=link(head); + page_tail=tail; + } +if (link(page_head)!=null) /*and both go before heldover contributions*/ + {@+if (link(contrib_head)==null) contrib_tail=page_tail; + link(page_tail)=link(contrib_head); + link(contrib_head)=link(page_head); + link(page_head)=null;page_tail=page_head; + } +pop_nest();build_page(); +} + +@ @<Recover from an unbalanced output routine@>= +{@+print_err("Unbalanced output routine"); +@.Unbalanced output routine@> +help2("Your sneaky output routine has problematic {'s and/or }'s.",@/ +"I can't handle that very well; good luck.");error(); +@/do@+{get_token(); +}@+ while (!(loc==null)); +} /*loops forever if reading from a file, since |null==min_halfword <= 0|*/ + +@ @<Ensure that box 255 is empty after output@>= +if (box(255)!=null) + {@+print_err("Output routine didn't use all of "); + print_esc("box");print_int(255); +@.Output routine didn't use...@> + help3("Your \\output commands should empty \\box255,",@/ + "e.g., by saying `\\shipout\\box255'.",@/ + "Proceed; I'll discard its present contents."); + box_error(255); + } + +@* The chief executive. +We come now to the |main_control| routine, which contains the master +switch that causes all the various pieces of \TeX\ to do their things, +in the right order. + +In a sense, this is the grand climax of the program: It applies all the +tools that we have worked so hard to construct. In another sense, this is +the messiest part of the program: It necessarily refers to other pieces +of code all over the place, so that a person can't fully understand what is +going on without paging back and forth to be reminded of conventions that +are defined elsewhere. We are now at the hub of the web, the central nervous +system that touches most of the other parts and ties them together. +@^brain@> + +The structure of |main_control| itself is quite simple. There's a label +called |big_switch|, at which point the next token of input is fetched +using |get_x_token|. Then the program branches at high speed into one of +about 100 possible directions, based on the value of the current +mode and the newly fetched command code; the sum |abs(mode)+cur_cmd| +indicates what to do next. For example, the case `|vmode+letter|' arises +when a letter occurs in vertical mode (or internal vertical mode); this +case leads to instructions that initialize a new paragraph and enter +horizontal mode. + +The big |case| statement that contains this multiway switch has been labeled +|reswitch|, so that the program can |goto reswitch| when the next token +has already been fetched. Most of the cases are quite short; they call +an ``action procedure'' that does the work for that case, and then they +either |goto reswitch| or they ``fall through'' to the end of the |case| +statement, which returns control back to |big_switch|. Thus, |main_control| +is not an extremely large procedure, in spite of the multiplicity of things +it must do; it is small enough to be handled by \PASCAL\ compilers that put +severe restrictions on procedure size. +@!@^action procedure@> + +One case is singled out for special treatment, because it accounts for most +of \TeX's activities in typical applications. The process of reading simple +text and converting it into |char_node| records, while looking for ligatures +and kerns, is part of \TeX's ``inner loop''; the whole program runs +efficiently when its inner loop is fast, so this part has been written +with particular care. + +@ We shall concentrate first on the inner loop of |main_control|, deferring +consideration of the other cases until later. +@^inner loop@> + +@p @t\4@>@<Declare action procedures for use by |main_control|@>@; +@t\4@>@<Declare the procedure called |handle_right_brace|@>@; +static void main_control(void) /*governs \TeX's activities*/ +{@+ + + + + +int @!t; /*general-purpose temporary variable*/ +if (every_job!=null) begin_token_list(every_job, every_job_text); +big_switch: get_x_token();@/ +reswitch: @<Give diagnostic information, if requested@>; +switch (abs(mode)+cur_cmd) { +case hmode+letter: case hmode+other_char: case hmode+char_given: goto main_loop; +case hmode+char_num: {@+scan_char_num();cur_chr=cur_val;goto main_loop;@+} +case hmode+no_boundary: {@+get_x_token(); + if ((cur_cmd==letter)||(cur_cmd==other_char)||(cur_cmd==char_given)|| + (cur_cmd==char_num)) cancel_boundary=true; + goto reswitch; + } +case hmode+spacer: if (space_factor==1000) goto append_normal_space; + else app_space();@+break; +case hmode+ex_space: case mmode+ex_space: goto append_normal_space; +@t\4@>@<Cases of |main_control| that are not part of the inner loop@>@; +} /*of the big |case| statement*/ +goto big_switch; +main_loop: @<Append character |cur_chr| and the following characters (if~any) to the +current hlist in the current font; |goto reswitch| when a non-character has been fetched@>; +append_normal_space: @<Append a normal inter-word space to the current list, then +|goto big_switch|@>; +} + +@ When a new token has just been fetched at |big_switch|, we have an +ideal place to monitor \TeX's activity. +@^debugging@> + +@<Give diagnostic information, if requested@>= +if (interrupt!=0) if (OK_to_interrupt) + {@+back_input();check_interrupt;goto big_switch; + } +#ifdef @!DEBUG +if (panicking) check_mem(false);@; +#endif +if (tracing_commands > 0) show_cur_cmd_chr() + +@ The following part of the program was first written in a structured +manner, according to the philosophy that ``premature optimization is +the root of all evil.'' Then it was rearranged into pieces of +spaghetti so that the most common actions could proceed with little or +no redundancy. + +The original unoptimized form of this algorithm resembles the +|reconstitute| procedure, which was described earlier in connection with +hyphenation. Again we have an implied ``cursor'' between characters +|cur_l| and |cur_r|. The main difference is that the |lig_stack| can now +contain a charnode as well as pseudo-ligatures; that stack is now +usually nonempty, because the next character of input (if any) has been +appended to it. In |main_control| we have +$$|cur_r|=\cases{|character(lig_stack)|,&if |lig_stack > null|;\cr + |font_bchar[cur_font]|,&otherwise;\cr}$$ +except when |character(lig_stack)==font_false_bchar[cur_font]|. +Several additional global variables are needed. + +@<Glob...@>= +static internal_font_number @!main_f; /*the current font*/ +static four_quarters @!main_i; /*character information bytes for |cur_l|*/ +static four_quarters @!main_j; /*ligature/kern command*/ +static font_index @!main_k; /*index into |font_info|*/ +static pointer @!main_p; /*temporary register for list manipulation*/ +static int @!main_s; /*space factor value*/ +static halfword @!bchar; /*right boundary character of current font, or |non_char|*/ +static halfword @!false_bchar; /*nonexistent character matching |bchar|, or |non_char|*/ +static bool @!cancel_boundary; /*should the left boundary be ignored?*/ +static bool @!ins_disc; /*should we insert a discretionary node?*/ + +@ The boolean variables of the main loop are normally false, and always reset +to false before the loop is left. That saves us the extra work of initializing +each time. + +@<Set init...@>= +ligature_present=false;cancel_boundary=false;lft_hit=false;rt_hit=false; +ins_disc=false; + +@ We leave the |space_factor| unchanged if |sf_code(cur_chr)==0|; otherwise we +set it equal to |sf_code(cur_chr)|, except that it should never change +from a value less than 1000 to a value exceeding 1000. The most common +case is |sf_code(cur_chr)==1000|, so we want that case to be fast. + +The overall structure of the main loop is presented here. Some program labels +are inside the individual sections. +@^inner loop@> + +@d adjust_space_factor @t@>@;@/ + main_s=sf_code(cur_chr); + if (main_s==1000) space_factor=1000; + else if (main_s < 1000) + {@+if (main_s > 0) space_factor=main_s; + } + else if (space_factor < 1000) space_factor=1000; + else space_factor=main_s + +@<Append character |cur_chr|...@>= +adjust_space_factor;@/ +main_f=cur_font; +bchar=font_bchar[main_f];false_bchar=font_false_bchar[main_f]; +if (mode > 0) if (language!=clang) fix_language(); +fast_get_avail(lig_stack);font(lig_stack)=main_f;cur_l=qi(cur_chr); +character(lig_stack)=cur_l;@/ +cur_q=tail; +if (cancel_boundary) + {@+cancel_boundary=false;main_k=non_address; + } +else main_k=bchar_label[main_f]; +if (main_k==non_address) goto main_loop_move2; /*no left boundary processing*/ +cur_r=cur_l;cur_l=non_char; +goto main_lig_loop1; /*begin with cursor after left boundary*/ +@# +main_loop_wrapup: @<Make a ligature node, if |ligature_present|; insert a null discretionary, +if appropriate@>; +main_loop_move: @<If the cursor is immediately followed by the right boundary, |goto +reswitch|; if it's followed by an invalid character, |goto big_switch|; otherwise +move the cursor one step to the right and |goto main_lig_loop|@>; +main_loop_lookahead: @<Look ahead for another character, or leave |lig_stack| empty +if there's none there@>; +main_lig_loop: @<If there's a ligature/kern command relevant to |cur_l| and |cur_r|, +adjust the text appropriately; exit to |main_loop_wrapup|@>; +main_loop_move_lig: @<Move the cursor past a pseudo-ligature, then |goto main_loop_lookahead| +or |main_lig_loop|@>@; + +@ If |link(cur_q)| is nonnull when |wrapup| is invoked, |cur_q| points to +the list of characters that were consumed while building the ligature +character~|cur_l|. + +A discretionary break is not inserted for an explicit hyphen when we are in +restricted horizontal mode. In particular, this avoids putting discretionary +nodes inside of other discretionaries. +@^inner loop@> + +@d pack_lig(X) /*the parameter is either |rt_hit| or |false|*/ + {@+main_p=new_ligature(main_f, cur_l, link(cur_q)); + if (lft_hit) + {@+subtype(main_p)=2;lft_hit=false; + } + if (X) if (lig_stack==null) + {@+incr(subtype(main_p));rt_hit=false; + } + link(cur_q)=main_p;tail=main_p;ligature_present=false; + } + +@d wrapup(A) if (cur_l < non_char) + {@+if (link(cur_q) > null) + if (character(tail)==qi(hyphen_char[main_f])) ins_disc=true; + if (ligature_present) pack_lig(A); + if (ins_disc) + {@+ins_disc=false; + if (mode > 0) tail_append(new_disc()); + } + } + +@<Make a ligature node, if |ligature_present|;...@>= +wrapup(rt_hit) + +@ @<If the cursor is immediately followed by the right boundary...@>= +@^inner loop@> +if (lig_stack==null) goto reswitch; +cur_q=tail;cur_l=character(lig_stack); +main_loop_move1: if (!is_char_node(lig_stack)) goto main_loop_move_lig; +main_loop_move2: if ((cur_chr < font_bc[main_f])||(cur_chr > font_ec[main_f])) + {@+char_warning(main_f, cur_chr);free_avail(lig_stack);goto big_switch; + } +main_i=char_info(main_f, cur_l); +if (!char_exists(main_i)) + {@+char_warning(main_f, cur_chr);free_avail(lig_stack);goto big_switch; + } +link(tail)=lig_stack;tail=lig_stack /*|main_loop_lookahead| is next*/ + +@ Here we are at |main_loop_move_lig|. +When we begin this code we have |cur_q==tail| and |cur_l==character(lig_stack)|. + +@<Move the cursor past a pseudo-ligature...@>= +main_p=lig_ptr(lig_stack); +if (main_p > null) tail_append(main_p); /*append a single character*/ +temp_ptr=lig_stack;lig_stack=link(temp_ptr); +free_node(temp_ptr, small_node_size); +main_i=char_info(main_f, cur_l);ligature_present=true; +if (lig_stack==null) + if (main_p > null) goto main_loop_lookahead; + else cur_r=bchar; +else cur_r=character(lig_stack); +goto main_lig_loop + +@ The result of \.{\\char} can participate in a ligature or kern, so we must +look ahead for it. + +@<Look ahead for another character...@>= +get_next(); /*set only |cur_cmd| and |cur_chr|, for speed*/ +if (cur_cmd==letter) goto main_loop_lookahead1; +if (cur_cmd==other_char) goto main_loop_lookahead1; +if (cur_cmd==char_given) goto main_loop_lookahead1; +x_token(); /*now expand and set |cur_cmd|, |cur_chr|, |cur_tok|*/ +if (cur_cmd==letter) goto main_loop_lookahead1; +if (cur_cmd==other_char) goto main_loop_lookahead1; +if (cur_cmd==char_given) goto main_loop_lookahead1; +if (cur_cmd==char_num) + {@+scan_char_num();cur_chr=cur_val;goto main_loop_lookahead1; + } +if (cur_cmd==no_boundary) bchar=non_char; +cur_r=bchar;lig_stack=null;goto main_lig_loop; +main_loop_lookahead1: adjust_space_factor; +fast_get_avail(lig_stack);font(lig_stack)=main_f; +cur_r=qi(cur_chr);character(lig_stack)=cur_r; +if (cur_r==false_bchar) cur_r=non_char /*this prevents spurious ligatures*/ + +@ Even though comparatively few characters have a lig/kern program, several +of the instructions here count as part of \TeX's inner loop, since a +@^inner loop@> +potentially long sequential search must be performed. For example, tests with +Computer Modern Roman showed that about 40 per cent of all characters +actually encountered in practice had a lig/kern program, and that about four +lig/kern commands were investigated for every such character. + +At the beginning of this code we have |main_i==char_info(main_f, cur_l)|. + +@<If there's a ligature/kern command...@>= +if (char_tag(main_i)!=lig_tag) goto main_loop_wrapup; +if (cur_r==non_char) goto main_loop_wrapup; +main_k=lig_kern_start(main_f, main_i);main_j=font_info[main_k].qqqq; +if (skip_byte(main_j) <= stop_flag) goto main_lig_loop2; +main_k=lig_kern_restart(main_f, main_j); +main_lig_loop1: main_j=font_info[main_k].qqqq; +main_lig_loop2: if (next_char(main_j)==cur_r) + if (skip_byte(main_j) <= stop_flag) + @<Do ligature or kern command, returning to |main_lig_loop| or |main_loop_wrapup| +or |main_loop_move|@>; +if (skip_byte(main_j)==qi(0)) incr(main_k); +else{@+if (skip_byte(main_j) >= stop_flag) goto main_loop_wrapup; + main_k=main_k+qo(skip_byte(main_j))+1; + } +goto main_lig_loop1 + +@ When a ligature or kern instruction matches a character, we know from +|read_font_info| that the character exists in the font, even though we +haven't verified its existence in the normal way. + +This section could be made into a subroutine, if the code inside +|main_control| needs to be shortened. + +\chardef\@@='174 % vertical line to indicate character retention + +@<Do ligature or kern command...@>= +{@+if (op_byte(main_j) >= kern_flag) + {@+wrapup(rt_hit); + tail_append(new_kern(char_kern(main_f, main_j)));goto main_loop_move; + } +if (cur_l==non_char) lft_hit=true; +else if (lig_stack==null) rt_hit=true; +check_interrupt; /*allow a way out in case there's an infinite ligature loop*/ +switch (op_byte(main_j)) { +case qi(1): case qi(5): {@+cur_l=rem_byte(main_j); /*\.{=:\@@}, \.{=:\@@>}*/ + main_i=char_info(main_f, cur_l);ligature_present=true; + } @+break; +case qi(2): case qi(6): {@+cur_r=rem_byte(main_j); /*\.{\@@=:}, \.{\@@=:>}*/ + if (lig_stack==null) /*right boundary character is being consumed*/ + {@+lig_stack=new_lig_item(cur_r);bchar=non_char; + } + else if (is_char_node(lig_stack)) /*|link(lig_stack)==null|*/ + {@+main_p=lig_stack;lig_stack=new_lig_item(cur_r); + lig_ptr(lig_stack)=main_p; + } + else character(lig_stack)=cur_r; + } @+break; +case qi(3): {@+cur_r=rem_byte(main_j); /*\.{\@@=:\@@}*/ + main_p=lig_stack;lig_stack=new_lig_item(cur_r); + link(lig_stack)=main_p; + } @+break; +case qi(7): case qi(11): {@+wrapup(false); /*\.{\@@=:\@@>}, \.{\@@=:\@@>>}*/ + cur_q=tail;cur_l=rem_byte(main_j); + main_i=char_info(main_f, cur_l);ligature_present=true; + } @+break; +default:{@+cur_l=rem_byte(main_j);ligature_present=true; /*\.{=:}*/ + if (lig_stack==null) goto main_loop_wrapup; + else goto main_loop_move1; + } +} +if (op_byte(main_j) > qi(4)) + if (op_byte(main_j)!=qi(7)) goto main_loop_wrapup; +if (cur_l < non_char) goto main_lig_loop; +main_k=bchar_label[main_f];goto main_lig_loop1; +} + +@ The occurrence of blank spaces is almost part of \TeX's inner loop, +@^inner loop@> +since we usually encounter about one space for every five non-blank characters. +Therefore |main_control| gives second-highest priority to ordinary spaces. + +When a glue parameter like \.{\\spaceskip} is set to `\.{0pt}', we will +see to it later that the corresponding glue specification is precisely +|zero_glue|, not merely a pointer to some specification that happens +to be full of zeroes. Therefore it is simple to test whether a glue parameter +is zero or~not. + +@<Append a normal inter-word space...@>= +if (space_skip==zero_glue) + {@+@<Find the glue specification, |main_p|, for text spaces in the current font@>; + temp_ptr=new_glue(main_p); + } +else temp_ptr=new_param_glue(space_skip_code); +link(tail)=temp_ptr;tail=temp_ptr; +goto big_switch + +@ Having |font_glue| allocated for each text font saves both time and memory. +If any of the three spacing parameters are subsequently changed by the +use of \.{\\fontdimen}, the |find_font_dimen| procedure deallocates the +|font_glue| specification allocated here. + +@<Find the glue specification...@>= +{@+main_p=font_glue[cur_font]; +if (main_p==null) + {@+main_p=new_spec(zero_glue);main_k=param_base[cur_font]+space_code; + width(main_p)=font_info[main_k].sc; /*that's |space(cur_font)|*/ + stretch(main_p)=font_info[main_k+1].sc; /*and |space_stretch(cur_font)|*/ + shrink(main_p)=font_info[main_k+2].sc; /*and |space_shrink(cur_font)|*/ + font_glue[cur_font]=main_p; + } +} + +@ @<Declare act...@>= +static void app_space(void) /*handle spaces when |space_factor!=1000|*/ +{@+pointer @!q; /*glue node*/ +if ((space_factor >= 2000)&&(xspace_skip!=zero_glue)) + q=new_param_glue(xspace_skip_code); +else{@+if (space_skip!=zero_glue) main_p=space_skip; + else@<Find the glue specification...@>; + main_p=new_spec(main_p); + @<Modify the glue specification in |main_p| according to the space factor@>; + q=new_glue(main_p);glue_ref_count(main_p)=null; + } +link(tail)=q;tail=q; +} + +@ @<Modify the glue specification in |main_p| according to the space factor@>= +if (space_factor >= 2000) width(main_p)=width(main_p)+extra_space(cur_font); +stretch(main_p)=xn_over_d(stretch(main_p), space_factor, 1000); +shrink(main_p)=xn_over_d(shrink(main_p), 1000, space_factor) + +@ Whew---that covers the main loop. We can now proceed at a leisurely +pace through the other combinations of possibilities. + +@d any_mode(A) case vmode+A: case hmode+A: case mmode+A /*for mode-independent commands*/ + +@<Cases of |main_control| that are not part of the inner loop@>= +any_mode(relax): case vmode+spacer: case mmode+spacer: case mmode+no_boundary: do_nothing; +any_mode(ignore_spaces): {@+@<Get the next non-blank non-call...@>; + goto reswitch; + } +case vmode+stop: if (its_all_over()) return;@+break; /*this is the only way out*/ +@t\4@>@<Forbidden cases detected in |main_control|@>@+@, any_mode(mac_param): + report_illegal_case();@+break; +@<Math-only cases in non-math modes, or vice versa@>: insert_dollar_sign();@+break; +@t\4@>@<Cases of |main_control| that build boxes and lists@>@; +@t\4@>@<Cases of |main_control| that don't depend on |mode|@>@; +@t\4@>@<Cases of |main_control| that are for extensions to \TeX@>@; + +@ Here is a list of cases where the user has probably gotten into or out of math +mode by mistake. \TeX\ will insert a dollar sign and rescan the current token. + +@d non_math(A) case vmode+A: case hmode+A + +@<Math-only cases in non-math modes...@>= +non_math(sup_mark): non_math(sub_mark): non_math(math_char_num): +non_math(math_given): non_math(math_comp): non_math(delim_num): +non_math(left_right): non_math(above): non_math(radical): +non_math(math_style): non_math(math_choice): non_math(vcenter): +non_math(non_script): non_math(mkern): non_math(limit_switch): +non_math(mskip): non_math(math_accent): +case mmode+endv: case mmode+par_end: case mmode+stop: case mmode+vskip: case mmode+un_vbox: +case mmode+valign: case mmode+hrule + +@ @<Declare action...@>= +static void insert_dollar_sign(void) +{@+back_input();cur_tok=math_shift_token+'$'; +print_err("Missing $ inserted"); +@.Missing \$ inserted@> +help2("I've inserted a begin-math/end-math symbol since I think",@/ +"you left one out. Proceed, with fingers crossed.");ins_error(); +} + +@ When erroneous situations arise, \TeX\ usually issues an error message +specific to the particular error. For example, `\.{\\noalign}' should +not appear in any mode, since it is recognized by the |align_peek| routine +in all of its legitimate appearances; a special error message is given +when `\.{\\noalign}' occurs elsewhere. But sometimes the most appropriate +error message is simply that the user is not allowed to do what he or she +has attempted. For example, `\.{\\moveleft}' is allowed only in vertical mode, +and `\.{\\lower}' only in non-vertical modes. Such cases are enumerated +here and in the other sections referred to under `See also \dots.' + +@<Forbidden cases...@>= +case vmode+vmove: case hmode+hmove: case mmode+hmove: any_mode(last_item): + +@ The `|you_cant|' procedure prints a line saying that the current command +is illegal in the current mode; it identifies these things symbolically. + +@<Declare action...@>= +static void you_cant(void) +{@+print_err("You can't use `"); +@.You can't use x in y mode@> +print_cmd_chr(cur_cmd, cur_chr); +print("' in ");print_mode(mode); +} + +@ @<Declare act...@>= +static void report_illegal_case(void) +{@+you_cant(); +help4("Sorry, but I'm not programmed to handle this case;",@/ +"I'll just pretend that you didn't ask for it.",@/ +"If you're in the wrong mode, you might be able to",@/ +"return to the right one by typing `I}' or `I$' or `I\\par'.");@/ +error(); +} + +@ Some operations are allowed only in privileged modes, i.e., in cases +that |mode > 0|. The |privileged| function is used to detect violations +of this rule; it issues an error message and returns |false| if the +current |mode| is negative. + +@<Declare act...@>= +static bool privileged(void) +{@+if (mode > 0) return true; +else{@+report_illegal_case();return false; + } +} + +@ Either \.{\\dump} or \.{\\end} will cause |main_control| to enter the +endgame, since both of them have `|stop|' as their command code. + +@<Put each...@>= +primitive("end", stop, 0);@/ +@!@:end\_}{\.{\\end} primitive@> +primitive("dump", stop, 1);@/ +@!@:dump\_}{\.{\\dump} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case stop: if (chr_code==1) print_esc("dump");@+else print_esc("end");@+break; + +@ We don't want to leave |main_control| immediately when a |stop| command +is sensed, because it may be necessary to invoke an \.{\\output} routine +several times before things really grind to a halt. (The output routine +might even say `\.{\\gdef\\end\{...\}}', to prolong the life of the job.) +Therefore |its_all_over| is |true| only when the current page +and contribution list are empty, and when the last output was not a +``dead cycle.'' + +@<Declare act...@>= +static bool its_all_over(void) /*do this when \.{\\end} or \.{\\dump} occurs*/ +{@+ +if (privileged()) + {@+if ((page_head==page_tail)&&(head==tail)&&(dead_cycles==0)) + {@+return true; + } + back_input(); /*we will try to end again after ejecting residual material*/ + tail_append(new_set_node()); + set_extent(tail)=new_xdimen(dimen_par(hsize_code), + dimen_par_hfactor(hsize_code),dimen_par_vfactor(hsize_code)); + tail_append(new_glue(fill_glue)); + tail_append(new_penalty(2*(eject_penalty)));@/ + build_page(); /*append \.{\\hbox to \\hsize\{\}\\vfill\\penalty-'10000000000}*/ + } +return false; +} + +@* Building boxes and lists. +The most important parts of |main_control| are concerned with \TeX's +chief mission of box-making. We need to control the activities that put +entries on vlists and hlists, as well as the activities that convert +those lists into boxes. All of the necessary machinery has already been +developed; it remains for us to ``push the buttons'' at the right times. + +@ As an introduction to these routines, let's consider one of the simplest +cases: What happens when `\.{\\hrule}' occurs in vertical mode, or +`\.{\\vrule}' in horizontal mode or math mode? The code in |main_control| +is short, since the |scan_rule_spec| routine already does most of what is +required; thus, there is no need for a special action procedure. + +Note that baselineskip calculations are disabled after a rule in vertical +mode, by setting |prev_depth=ignore_depth|. + +@<Cases of |main_control| that build...@>= +case vmode+hrule: case hmode+vrule: case mmode+vrule: {@+tail_append(scan_rule_spec()); + if (abs(mode)==vmode) prev_depth=ignore_depth; + else if (abs(mode)==hmode) space_factor=1000; + } @+break; + +@ The processing of things like \.{\\hskip} and \.{\\vskip} is slightly +more complicated. But the code in |main_control| is very short, since +it simply calls on the action routine |append_glue|. Similarly, \.{\\kern} +activates |append_kern|. + +@<Cases of |main_control| that build...@>= +case vmode+vskip: case hmode+hskip: case mmode+hskip: case mmode+mskip: append_glue();@+break; +any_mode(kern): case mmode+mkern: append_kern();@+break; + +@ The |hskip| and |vskip| command codes are used for control sequences +like \.{\\hss} and \.{\\vfil} as well as for \.{\\hskip} and \.{\\vskip}. +The difference is in the value of |cur_chr|. + +@d fil_code 0 /*identifies \.{\\hfil} and \.{\\vfil}*/ +@d fill_code 1 /*identifies \.{\\hfill} and \.{\\vfill}*/ +@d ss_code 2 /*identifies \.{\\hss} and \.{\\vss}*/ +@d fil_neg_code 3 /*identifies \.{\\hfilneg} and \.{\\vfilneg}*/ +@d skip_code 4 /*identifies \.{\\hskip} and \.{\\vskip}*/ +@d mskip_code 5 /*identifies \.{\\mskip}*/ + +@<Put each...@>= +primitive("hskip", hskip, skip_code);@/ +@!@:hskip\_}{\.{\\hskip} primitive@> +primitive("hfil", hskip, fil_code); +@!@:hfil\_}{\.{\\hfil} primitive@> +primitive("hfill", hskip, fill_code);@/ +@!@:hfill\_}{\.{\\hfill} primitive@> +primitive("hss", hskip, ss_code); +@!@:hss\_}{\.{\\hss} primitive@> +primitive("hfilneg", hskip, fil_neg_code);@/ +@!@:hfil\_neg\_}{\.{\\hfilneg} primitive@> +primitive("vskip", vskip, skip_code);@/ +@!@:vskip\_}{\.{\\vskip} primitive@> +primitive("vfil", vskip, fil_code); +@!@:vfil\_}{\.{\\vfil} primitive@> +primitive("vfill", vskip, fill_code);@/ +@!@:vfill\_}{\.{\\vfill} primitive@> +primitive("vss", vskip, ss_code); +@!@:vss\_}{\.{\\vss} primitive@> +primitive("vfilneg", vskip, fil_neg_code);@/ +@!@:vfil\_neg\_}{\.{\\vfilneg} primitive@> +primitive("mskip", mskip, mskip_code);@/ +@!@:mskip\_}{\.{\\mskip} primitive@> +primitive("kern", kern, explicit); +@!@:kern\_}{\.{\\kern} primitive@> +primitive("mkern", mkern, mu_glue);@/ +@!@:mkern\_}{\.{\\mkern} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case hskip: switch (chr_code) { + case skip_code: print_esc("hskip");@+break; + case fil_code: print_esc("hfil");@+break; + case fill_code: print_esc("hfill");@+break; + case ss_code: print_esc("hss");@+break; + default:print_esc("hfilneg"); + } @+break; +case vskip: switch (chr_code) { + case skip_code: print_esc("vskip");@+break; + case fil_code: print_esc("vfil");@+break; + case fill_code: print_esc("vfill");@+break; + case ss_code: print_esc("vss");@+break; + default:print_esc("vfilneg"); + } @+break; +case mskip: print_esc("mskip");@+break; +case kern: print_esc("kern");@+break; +case mkern: print_esc("mkern");@+break; + +@ All the work relating to glue creation has been relegated to the +following subroutine. It does not call |build_page|, because it is +used in at least one place where that would be a mistake. + +@<Declare action...@>= +static void append_glue(void) +{@+small_number s; /*modifier of skip command*/ +s=cur_chr; +switch (s) { +case fil_code: cur_val=fil_glue;@+break; +case fill_code: cur_val=fill_glue;@+break; +case ss_code: cur_val=ss_glue;@+break; +case fil_neg_code: cur_val=fil_neg_glue;@+break; +case skip_code: scan_glue(glue_val);@+break; +case mskip_code: scan_glue(mu_val); +} /*now |cur_val| points to the glue specification*/ +tail_append(new_glue(cur_val)); +if (s >= skip_code) + {@+decr(glue_ref_count(cur_val)); + if (s > skip_code) subtype(tail)=mu_glue; + } +} + +@ @<Declare act...@>= +static void append_kern(void) +{@+quarterword s; /*|subtype| of the kern node*/ +s=cur_chr;scan_dimen(s==mu_glue, false, false); +tail_append(new_kern(cur_val));subtype(tail)=s; +} + +@ Many of the actions related to box-making are triggered by the appearance +of braces in the input. For example, when the user says `\.{\\hbox} +\.{to} \.{100pt\{$\langle\,\hbox{hlist}\,\rangle$\}}' in vertical mode, +the information about the box size (100pt, |exactly|) is put onto |save_stack| +with a level boundary word just above it, and |cur_group=adjusted_hbox_group|; +\TeX\ enters restricted horizontal mode to process the hlist. The right +brace eventually causes |save_stack| to be restored to its former state, +at which time the information about the box size (100pt, |exactly|) is +available once again; a box is packaged and we leave restricted horizontal +mode, appending the new box to the current list of the enclosing mode +(in this case to the current list of vertical mode), followed by any +vertical adjustments that were removed from the box by |hpack|. + +The next few sections of the program are therefore concerned with the +treatment of left and right curly braces. + +@ If a left brace occurs in the middle of a page or paragraph, it simply +introduces a new level of grouping, and the matching right brace will not have +such a drastic effect. Such grouping affects neither the mode nor the +current list. + +@<Cases of |main_control| that build...@>= +non_math(left_brace): new_save_level(simple_group);@+break; +any_mode(begin_group): new_save_level(semi_simple_group);@+break; +any_mode(end_group): if (cur_group==semi_simple_group) unsave(); + else off_save();@+break; + +@ We have to deal with errors in which braces and such things are not +properly nested. Sometimes the user makes an error of commission by +inserting an extra symbol, but sometimes the user makes an error of omission. +\TeX\ can't always tell one from the other, so it makes a guess and tries +to avoid getting into a loop. + +The |off_save| routine is called when the current group code is wrong. It tries +to insert something into the user's input that will help clean off +the top level. + +@<Declare act...@>= +static void off_save(void) +{@+pointer p; /*inserted token*/ +if (cur_group==bottom_level) + @<Drop current token and complain that it was unmatched@>@; +else{@+back_input();p=get_avail();link(temp_head)=p; + print_err("Missing "); + @<Prepare to insert a token that matches |cur_group|, and print what it is@>; + print(" inserted");ins_list(link(temp_head)); + help5("I've inserted something that you may have forgotten.",@/ + "(See the <inserted text> above.)",@/ + "With luck, this will get me unwedged. But if you",@/ + "really didn't forget anything, try typing `2' now; then",@/ + "my insertion and my current dilemma will both disappear."); + error(); + } +} + +@ At this point, |link(temp_head)==p|, a pointer to an empty one-word node. + +@<Prepare to insert a token that matches |cur_group|...@>= +switch (cur_group) { +case semi_simple_group: {@+info(p)=cs_token_flag+frozen_end_group; + print_esc("endgroup"); +@.Missing \\endgroup inserted@> + } @+break; +case math_shift_group: {@+info(p)=math_shift_token+'$';print_char('$'); +@.Missing \$ inserted@> + } @+break; +case math_left_group: {@+info(p)=cs_token_flag+frozen_right;link(p)=get_avail(); + p=link(p);info(p)=other_token+'.';print_esc("right."); +@.Missing \\right\hbox{.} inserted@> +@^null delimiter@> + } @+break; +default:{@+info(p)=right_brace_token+'}';print_char('}'); +@.Missing \} inserted@> + } +} + +@ @<Drop current token and complain that it was unmatched@>= +{@+print_err("Extra ");print_cmd_chr(cur_cmd, cur_chr); +@.Extra x@> +help1("Things are pretty mixed up, but I think the worst is over.");@/ +error(); +} + +@ The routine for a |right_brace| character branches into many subcases, +since a variety of things may happen, depending on |cur_group|. Some +types of groups are not supposed to be ended by a right brace; error +messages are given in hopes of pinpointing the problem. Most branches +of this routine will be filled in later, when we are ready to understand +them; meanwhile, we must prepare ourselves to deal with such errors. + +@<Cases of |main_control| that build...@>= +any_mode(right_brace): handle_right_brace();@+break; + +@ @<Declare the procedure called |handle_right_brace|@>= +static void handle_right_brace(void) +{@+pointer p, @!q; /*for short-term use*/ +scaled @!d; /*holds |split_max_depth| in |insert_group|*/ +int @!f; /*holds |floating_penalty| in |insert_group|*/ +switch (cur_group) { +case simple_group: unsave();@+break; +case bottom_level: {@+print_err("Too many }'s"); +@.Too many \}'s@> + help2("You've closed more groups than you opened.",@/ + "Such booboos are generally harmless, so keep going.");error(); + } @+break; +case semi_simple_group: case math_shift_group: case math_left_group: extra_right_brace();@+break; +@t\4@>@<Cases of |handle_right_brace| where a |right_brace| triggers a delayed action@>@; +default:confusion("rightbrace"); +@:this can't happen rightbrace}{\quad rightbrace@> +} +} + +@ @<Declare act...@>= +static void extra_right_brace(void) +{@+print_err("Extra }, or forgotten "); +@.Extra \}, or forgotten x@> +switch (cur_group) { +case semi_simple_group: print_esc("endgroup");@+break; +case math_shift_group: print_char('$');@+break; +case math_left_group: print_esc("right"); +} @/ +help5("I've deleted a group-closing symbol because it seems to be",@/ +"spurious, as in `$x}$'. But perhaps the } is legitimate and",@/ +"you forgot something else, as in `\\hbox{$x}'. In such cases",@/ +"the way to recover is to insert both the forgotten and the",@/ +"deleted material, e.g., by typing `I$}'.");error(); +incr(align_state); +} + +@ Here is where we clear the parameters that are supposed to revert to their +default values after every paragraph and when internal vertical mode is entered. + +@<Declare act...@>= +void normal_paragraph(void) +{@+if (looseness!=0) eq_word_define(int_base+looseness_code, 0); +if (hang_indent!=0) eq_word_define(dimen_base+hang_indent_code, 0); +if (hang_after!=1) eq_word_define(int_base+hang_after_code, 1); +if (par_shape_ptr!=null) eq_define(par_shape_loc, shape_ref, null); +if (inter_line_penalties_ptr!=null) + eq_define(inter_line_penalties_loc, shape_ref, null); +} + +@ Now let's turn to the question of how \.{\\hbox} is treated. We actually +need to consider also a slightly larger context, since constructions like +`\.{\\setbox3=}\penalty0\.{\\hbox...}' and +`\.{\\leaders}\penalty0\.{\\hbox...}' and +`\.{\\lower3.8pt\\hbox...}' +are supposed to invoke quite +different actions after the box has been packaged. Conversely, +constructions like `\.{\\setbox3=}' can be followed by a variety of +different kinds of boxes, and we would like to encode such things in an +efficient way. + +In other words, there are two problems: to represent the context of a box, +and to represent its type. + +The first problem is solved by putting a ``context code'' on the |save_stack|, +just below the two entries that give the dimensions produced by |scan_spec|. +The context code is either a (signed) shift amount, or it is a large +integer | >= box_flag|, where |box_flag==@t$2^{30}$@>|. Codes |box_flag| through +|global_box_flag-1| represent `\.{\\setbox0}' through `\.{\\setbox32767}'; +codes |global_box_flag| through |ship_out_flag-1| represent +`\.{\\global\\setbox0}' through `\.{\\global\\setbox32767}'; +code |ship_out_flag| represents `\.{\\shipout}'; and codes |leader_flag| +through |leader_flag+2| represent `\.{\\leaders}', `\.{\\cleaders}', +and `\.{\\xleaders}'. + +The second problem is solved by giving the command code |make_box| to all +control sequences that produce a box, and by using the following |chr_code| +values to distinguish between them: |box_code|, |copy_code|, |last_box_code|, +|vsplit_code|, |vtop_code|, |vtop_code+vmode|, and |vtop_code+hmode|, where +the latter two are used to denote \.{\\vbox} and \.{\\hbox}, respectively. + +@d box_flag 010000000000 /*context code for `\.{\\setbox0}'*/ +@d global_box_flag 010000100000 /*context code for `\.{\\global\\setbox0}'*/ +@d ship_out_flag 010000200000 /*context code for `\.{\\shipout}'*/ +@d leader_flag 010000200001 /*context code for `\.{\\leaders}'*/ +@d box_code 0 /*|chr_code| for `\.{\\box}'*/ +@d copy_code 1 /*|chr_code| for `\.{\\copy}'*/ +@d last_box_code 2 /*|chr_code| for `\.{\\lastbox}'*/ +@d vsplit_code 3 /*|chr_code| for `\.{\\vsplit}'*/ +@d vtop_code 4 /*|chr_code| for `\.{\\vtop}'*/ + +@<Put each...@>= +primitive("moveleft", hmove, 1); +@!@:move\_left\_}{\.{\\moveleft} primitive@> +primitive("moveright", hmove, 0);@/ +@!@:move\_right\_}{\.{\\moveright} primitive@> +primitive("raise", vmove, 1); +@!@:raise\_}{\.{\\raise} primitive@> +primitive("lower", vmove, 0); +@!@:lower\_}{\.{\\lower} primitive@> +@# +primitive("box", make_box, box_code); +@!@:box\_}{\.{\\box} primitive@> +primitive("copy", make_box, copy_code); +@!@:copy\_}{\.{\\copy} primitive@> +primitive("lastbox", make_box, last_box_code); +@!@:last\_box\_}{\.{\\lastbox} primitive@> +primitive("vsplit", make_box, vsplit_code); +@!@:vsplit\_}{\.{\\vsplit} primitive@> +primitive("vtop", make_box, vtop_code);@/ +@!@:vtop\_}{\.{\\vtop} primitive@> +primitive("vbox", make_box, vtop_code+vmode); +@!@:vbox\_}{\.{\\vbox} primitive@> +primitive("hbox", make_box, vtop_code+hmode);@/ +@!@:hbox\_}{\.{\\hbox} primitive@> +primitive("shipout", leader_ship, a_leaders-1); /*|ship_out_flag==leader_flag-1|*/ +@!@:ship\_out\_}{\.{\\shipout} primitive@> +primitive("leaders", leader_ship, a_leaders); +@!@:leaders\_}{\.{\\leaders} primitive@> +primitive("cleaders", leader_ship, c_leaders); +@!@:c\_leaders\_}{\.{\\cleaders} primitive@> +primitive("xleaders", leader_ship, x_leaders); +@!@:x\_leaders\_}{\.{\\xleaders} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case hmove: if (chr_code==1) print_esc("moveleft");@+else print_esc("moveright");@+break; +case vmove: if (chr_code==1) print_esc("raise");@+else print_esc("lower");@+break; +case make_box: switch (chr_code) { + case box_code: print_esc("box");@+break; + case copy_code: print_esc("copy");@+break; + case last_box_code: print_esc("lastbox");@+break; + case vsplit_code: print_esc("vsplit");@+break; + case vtop_code: print_esc("vtop");@+break; + case vtop_code+vmode: print_esc("vbox");@+break; + default:print_esc("hbox"); + } @+break; +case leader_ship: if (chr_code==a_leaders) print_esc("leaders"); + else if (chr_code==c_leaders) print_esc("cleaders"); + else if (chr_code==x_leaders) print_esc("xleaders"); + else print_esc("shipout");@+break; + +@ Constructions that require a box are started by calling |scan_box| with +a specified context code. The |scan_box| routine verifies +that a |make_box| command comes next and then it calls |begin_box|. + +@<Cases of |main_control| that build...@>= +case vmode+hmove: case hmode+vmove: case mmode+vmove: {@+t=cur_chr; + scan_normal_dimen; + if (t==0) scan_box(cur_val);@+else scan_box(-cur_val); + } @+break; +any_mode(leader_ship): scan_box(leader_flag-a_leaders+cur_chr);@+break; +any_mode(make_box): begin_box(0);@+break; + +@ The global variable |cur_box| will point to a newly made box. If the box +is void, we will have |cur_box==null|. Otherwise we will have +|type(cur_box)==hlist_node| or |vlist_node| or |rule_node|; the |rule_node| +case can occur only with leaders. + +@<Glob...@>= +static pointer @!cur_box; /*box to be placed into its context*/ + +@ The |box_end| procedure does the right thing with |cur_box|, if +|box_context| represents the context as explained above. + +@<Declare act...@>= +static void box_end(int @!box_context) +{@+pointer p; /*|ord_noad| for new box in math mode*/ +small_number @!a; /*global prefix*/ +if (box_context < box_flag) @<Append box |cur_box| to the current list, shifted by +|box_context|@>@; +else if (box_context < ship_out_flag) @<Store \(c)|cur_box| in a box register@>@; +else if (cur_box!=null) + if (box_context > ship_out_flag) @<Append a new leader node that uses |cur_box|@>@; + else ship_out(cur_box); +} + +@ The global variable |adjust_tail| will be non-null if and only if the +current box might include adjustments that should be appended to the +current vertical list. + +@<Append box |cur_box| to the current...@>= +{@+if (cur_box!=null) + {@+shift_amount(cur_box)=box_context; + if (abs(mode)==vmode) + {@+append_to_vlist(cur_box); + if (adjust_tail!=null) + {@+if (adjust_head!=adjust_tail) + {@+link(tail)=link(adjust_head);tail=adjust_tail; + } + adjust_tail=null; + } + if (mode > 0) build_page(); + } + else{@+if (abs(mode)==hmode) space_factor=1000; + else{@+p=new_noad(); + math_type(nucleus(p))=sub_box; + info(nucleus(p))=cur_box;cur_box=p; + } + link(tail)=cur_box;tail=cur_box; + } + } +} + +@ @<Store \(c)|cur_box| in a box register@>= +{@+if (box_context < global_box_flag) + {@+cur_val=box_context-box_flag;a=0; + } +else{@+cur_val=box_context-global_box_flag;a=4; + } +if (cur_val < 256) define(box_base+cur_val, box_ref, cur_box); +else sa_def_box; +} + +@ @<Append a new leader node...@>= +{@+@<Get the next non-blank non-relax...@>; +if (((cur_cmd==hskip)&&(abs(mode)!=vmode))||@| + ((cur_cmd==vskip)&&(abs(mode)==vmode))) + {@+append_glue();subtype(tail)=box_context-(leader_flag-a_leaders); + leader_ptr(tail)=cur_box; + } +else{@+print_err("Leaders not followed by proper glue"); +@.Leaders not followed by...@> + help3("You should say `\\leaders <box or rule><hskip or vskip>'.",@/ + "I found the <box or rule>, but there's no suitable",@/ + "<hskip or vskip>, so I'm ignoring these leaders.");back_error(); + flush_node_list(cur_box); + } +} + +@ Now that we can see what eventually happens to boxes, we can consider +the first steps in their creation. The |begin_box| routine is called when +|box_context| is a context specification, |cur_chr| specifies the type of +box desired, and |cur_cmd==make_box|. + +@<Declare act...@>= +static void begin_box(int @!box_context) +{@+ +pointer @!p, @!q; /*run through the current list*/ +int @!m; /*the length of a replacement list*/ +halfword @!k; /*0 or |vmode| or |hmode|*/ +halfword @!n; /*a box number*/ +switch (cur_chr) { +case box_code: {@+scan_register_num();fetch_box(cur_box); + change_box(null); /*the box becomes void, at the same level*/ + } @+break; +case copy_code: {@+scan_register_num();fetch_box(q);cur_box=copy_node_list(q); + } @+break; +case last_box_code: @<If the current list ends with a box node, delete it from the +list and make |cur_box| point to it; otherwise set |cur_box:=null|@>@;@+break; +case vsplit_code: @<Split off part of a vertical box, make |cur_box| point to it@>@;@+break; +default:@<Initiate the construction of an hbox or vbox, then |return|@>@; +} @/ +box_end(box_context); /*in simple cases, we use the box immediately*/ +} + +@ Note that the condition |!is_char_node(tail)| implies that |head!=tail|, +since |head| is a one-word node. + +@<If the current list ends with a box node, delete it...@>= +{@+cur_box=null; +if (abs(mode)==mmode) + {@+you_cant();help1("Sorry; this \\lastbox will be void.");error(); + } +else if ((mode==vmode)&&(head==tail)) + {@+you_cant(); + help2("Sorry...I usually can't take things from the current page.",@/ + "This \\lastbox will therefore be void.");error(); + } +else{@+if (!is_char_node(tail)) + if ((type(tail)==hlist_node)||(type(tail)==vlist_node)) + @<Remove the last box, unless it's part of a discretionary@>; + } +} + +@ @<Remove the last box...@>= +{@+q=head; +@/do@+{p=q; +if (!is_char_node(q)) if (type(q)==disc_node) + {@+for (m=1; m<=replace_count(q); m++) p=link(p); + if (p==tail) goto done; + } +q=link(p); +}@+ while (!(q==tail)); +cur_box=tail;shift_amount(cur_box)=0; +tail=p;link(p)=null; +done: ;} + +@ Here we deal with things like `\.{\\vsplit 13 to 100pt}'. + +@<Split off part of a vertical box, make |cur_box| point to it@>= +{@+scan_register_num();n=cur_val; +if (!scan_keyword("to")) +@.to@> + {@+print_err("Missing `to' inserted"); +@.Missing `to' inserted@> + help2("I'm working on `\\vsplit<box number> to <dimen>';",@/ + "will look for the <dimen> next.");error(); + } +scan_normal_dimen; +cur_box=vsplit(n, cur_val); +} + +@ Here is where we enter restricted horizontal mode or internal vertical +mode, in order to make a box. + +@<Initiate the construction of an hbox or vbox, then |return|@>= +{@+k=cur_chr-vtop_code;saved(0)=box_context; +if (k==hmode) + if ((box_context < box_flag)&&(abs(mode)==vmode)) + scan_spec(adjusted_hbox_group, true); + else scan_spec(hbox_group, true); +else{@+if (k==vmode) scan_spec(vbox_group, true); + else{@+scan_spec(vtop_group, true);k=vmode; + } + normal_paragraph(); + } +push_nest();mode=-k; +if (k==vmode) + {@+prev_depth=ignore_depth; + if (every_vbox!=null) begin_token_list(every_vbox, every_vbox_text); + } +else{@+space_factor=1000; + if (every_hbox!=null) begin_token_list(every_hbox, every_hbox_text); + } +return; +} + +@ @<Declare act...@>= +static void scan_box(int @!box_context) + /*the next input should specify a box or perhaps a rule*/ +{@+@<Get the next non-blank non-relax...@>; +if (cur_cmd==make_box) begin_box(box_context); +else if ((box_context >= leader_flag)&&((cur_cmd==hrule)||(cur_cmd==vrule))) + {@+cur_box=scan_rule_spec();box_end(box_context); + } +else{@+@t@>@;@/ + print_err("A <box> was supposed to be here");@/ +@.A <box> was supposed to...@> + help3("I was expecting to see \\hbox or \\vbox or \\copy or \\box or",@/ + "something like that. So you might find something missing in",@/ + "your output. But keep trying; you can fix this later.");back_error(); + } +} + +@ When the right brace occurs at the end of an \.{\\hbox} or \.{\\vbox} or +\.{\\vtop} construction, the |package| routine comes into action. We might +also have to finish a paragraph that hasn't ended. + +@<Cases of |handle...@>= +case hbox_group: package(0);@+break; +case adjusted_hbox_group: {@+adjust_tail=adjust_head;package(0); + } @+break; +case vbox_group: {@+end_graf();package(0); + } @+break; +case vtop_group: {@+end_graf();package(vtop_code); + } @+break; + +@ @<Declare action...@>= +static void package(small_number @!c) +{@+scaled h; /*height of box*/ +pointer @!p; /*first node in a box*/ +scaled @!d; /*max depth*/ +d=box_max_depth;unsave();save_ptr=save_ptr-3; +if (mode==-hmode) cur_box=hpack(link(head), saved(2), saved_hfactor(2), saved_vfactor(2), saved(1)); +else{@+cur_box=vpackage(link(head), saved(2), saved_hfactor(2), saved_vfactor(2), saved(1), d); + if (c==vtop_code) @<Readjust the height and depth of |cur_box|, for \.{\\vtop}@>; + } +pop_nest();box_end(saved(0)); +} + +@ The height of a `\.{\\vtop}' box is inherited from the first item on its list, +if that item is an |hlist_node|, |vlist_node|, or |rule_node|; otherwise +the \.{\\vtop} height is zero. + + +@<Readjust the height...@>= +{@+h=0;p=list_ptr(cur_box); +if (p!=null) if (type(p) <= rule_node) h=height(p); +depth(cur_box)=depth(cur_box)-h+height(cur_box);height(cur_box)=h; +} + +@ A paragraph begins when horizontal-mode material occurs in vertical mode, +or when the paragraph is explicitly started by `\.{\\indent}' or +`\.{\\noindent}'. + +@<Put each...@>= +primitive("indent", start_par, 1); +@!@:indent\_}{\.{\\indent} primitive@> +primitive("noindent", start_par, 0); +@!@:no\_indent\_}{\.{\\noindent} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case start_par: if (chr_code==0) print_esc("noindent");@+else print_esc("indent");@+break; + +@ @<Cases of |main_control| that build...@>= +case vmode+start_par: new_graf(cur_chr > 0);@+break; +case vmode+letter: case vmode+other_char: case vmode+char_num: case vmode+char_given: + case vmode+math_shift: case vmode+un_hbox: case vmode+vrule: + case vmode+accent: case vmode+discretionary: case vmode+hskip: case vmode+valign: + case vmode+ex_space: case vmode+no_boundary: @t@>@;@/ + {@+back_input();new_graf(true); + } @+break; + +@ @<Declare act...@>= +static small_number norm_min(int @!h) +{@+if (h <= 0) return 1;@+else if (h >= 63) return 63;@+ +else return h; +} +@# +static void new_graf(bool @!indented) +{@+prev_graf=0; +if ((mode==vmode)||(head!=tail)) + tail_append(new_param_glue(par_skip_code)); +push_nest();mode=hmode;space_factor=1000;set_cur_lang;clang=cur_lang; +prev_graf=(norm_min(left_hyphen_min)*0100+norm_min(right_hyphen_min)) + *0200000+cur_lang; +if (indented) + {@+tail=new_null_box();link(head)=tail;width(tail)=par_indent;@+ + } +if (every_par!=null) begin_token_list(every_par, every_par_text); +if (nest_ptr==1) build_page(); /*put |par_skip| glue on current page*/ +} + +@ @<Cases of |main_control| that build...@>= +case hmode+start_par: case mmode+start_par: indent_in_hmode();@+break; + +@ @<Declare act...@>= +static void indent_in_hmode(void) +{@+pointer p, @!q; +if (cur_chr > 0) /*\.{\\indent}*/ + {@+p=new_null_box();width(p)=par_indent; + if (abs(mode)==hmode) space_factor=1000; + else{@+q=new_noad();math_type(nucleus(q))=sub_box; + info(nucleus(q))=p;p=q; + } + tail_append(p); + } +} + +@ A paragraph ends when a |par_end| command is sensed, or when we are in +horizontal mode when reaching the right brace of vertical-mode routines +like \.{\\vbox}, \.{\\insert}, or \.{\\output}. + +@<Cases of |main_control| that build...@>= +case vmode+par_end: {@+normal_paragraph(); + if (mode > 0) build_page(); + } @+break; +case hmode+par_end: {@+if (align_state < 0) off_save(); /*this tries to + recover from an alignment that didn't end properly*/ + end_graf(); /*this takes us to the enclosing mode, if |mode > 0|*/ + if (mode==vmode) build_page(); + } @+break; +case hmode+stop: case hmode+vskip: case hmode+hrule: case hmode+un_vbox: case hmode+halign: head_for_vmode();@+break; + +@ @<Declare act...@>= +static void head_for_vmode(void) +{@+if (mode < 0) + if (cur_cmd!=hrule) off_save(); + else{@+print_err("You can't use `"); + print_esc("hrule");print("' here except with leaders"); +@.You can't use \\hrule...@> + help2("To put a horizontal rule in an hbox or an alignment,",@/ + "you should use \\leaders or \\hrulefill (see The TeXbook)."); + error(); + } +else{@+back_input();cur_tok=par_token;back_input();token_type=inserted; + } +} + +@ @<Declare act...@>= +void end_graf(void) +{@+if (mode==hmode) + {@+if (head==tail) pop_nest(); /*null paragraphs are ignored*/ + else hline_break(widow_penalty); + normal_paragraph(); + error_count=0; + } +} + +@ Insertion and adjustment and mark nodes are constructed by the following +pieces of the program. + +@<Cases of |main_control| that build...@>= +any_mode(insert): case hmode+vadjust: case mmode+vadjust: begin_insert_or_adjust();@+break; +any_mode(mark): make_mark();@+break; + +@ @<Forbidden...@>= +case vmode+vadjust: + +@ @<Declare act...@>= +static void begin_insert_or_adjust(void) +{@+if (cur_cmd==vadjust) cur_val=255; +else{@+scan_eight_bit_int(); + if (cur_val==255) + {@+print_err("You can't ");print_esc("insert");print_int(255); +@.You can't \\insert255@> + help1("I'm changing to \\insert0; box 255 is special."); + error();cur_val=0; + } + } +saved(0)=cur_val;incr(save_ptr); +new_save_level(insert_group);scan_left_brace();normal_paragraph(); +push_nest();mode=-vmode;prev_depth=ignore_depth; +} + +@ @<Cases of |handle...@>= +case insert_group: {@+end_graf();q=split_top_skip;add_glue_ref(q); + d=split_max_depth;f=floating_penalty;unsave();decr(save_ptr); + /*now |saved(0)| is the insertion number, or 255 for |vadjust|*/ + p=link(head);pop_nest(); + if (saved(0) < 255) + {@+tail_append(get_node(ins_node_size)); + type(tail)=ins_node;subtype(tail)=qi(saved(0)); + height(tail)=0; ins_ptr(tail)=p; hget_stream_no(subtype(tail)); + split_top_ptr(tail)=q;depth(tail)=d;float_cost(tail)=f; + } + else{@+tail_append(get_node(small_node_size)); + type(tail)=adjust_node;@/ + subtype(tail)=0; /*the |subtype| is not used*/ + adjust_ptr(tail)=p;delete_glue_ref(q); + } + if (nest_ptr==0) build_page(); + } @+break; +case output_group: @<Resume the page builder...@>@;@+break; +case page_group: hfinish_page_group();@+break; +case stream_group: hfinish_stream_group();@+break; +case stream_before_group: hfinish_stream_before_group();@+break; +case stream_after_group: hfinish_stream_after_group();@+break; +case outline_group: hfinish_outline_group();@+break; + +@ @<Declare act...@>= +static void make_mark(void) +{@+pointer p; /*new node*/ +p=scan_toks(false, true);p=get_node(small_node_size); +type(p)=mark_node;subtype(p)=0; /*the |subtype| is not used*/ +mark_ptr(p)=def_ref;link(tail)=p;tail=p; +} + +@ Penalty nodes get into a list via the |break_penalty| command. +@^penalties@> + +@<Cases of |main_control| that build...@>= +any_mode(break_penalty): append_penalty();@+break; + +@ @<Declare action...@>= +static void append_penalty(void) +{@+scan_int();tail_append(new_penalty(cur_val)); +if (mode==vmode) build_page(); +} + +@ The |remove_item| command removes a penalty, kern, or glue node if it +appears at the tail of the current list, using a brute-force linear scan. +Like \.{\\lastbox}, this command is not allowed in vertical mode (except +internal vertical mode), since the current list in vertical mode is sent +to the page builder. But if we happen to be able to implement it in +vertical mode, we do. + +@<Cases of |main_control| that build...@>= +any_mode(remove_item): delete_last();@+break; + +@ When |delete_last| is called, |cur_chr| is the |type| of node that +will be deleted, if present. + +@<Declare action...@>= +static void delete_last(void) +{@+ +pointer @!p, @!q; /*run through the current list*/ +int @!m; /*the length of a replacement list*/ +if ((mode==vmode)&&(tail==head)) + @<Apologize for inability to do the operation now, unless \.{\\unskip} follows non-glue@>@; +else{@+if (!is_char_node(tail)) if (type(tail)==cur_chr) + {@+q=head; + @/do@+{p=q; + if (!is_char_node(q)) if (type(q)==disc_node) + {@+for (m=1; m<=replace_count(q); m++) p=link(p); + if (p==tail) return; + } + q=link(p); + }@+ while (!(q==tail)); + link(p)=null;flush_node_list(tail);tail=p; + } + } +} + +@ @<Apologize for inability to do the operation...@>= +{@+if ((cur_chr!=glue_node)||(last_glue!=max_halfword)) + {@+you_cant(); + help2("Sorry...I usually can't take things from the current page.",@/ + "Try `I\\vskip-\\lastskip' instead."); + if (cur_chr==kern_node) help_line[0]= + ("Try `I\\kern-\\lastkern' instead."); + else if (cur_chr!=glue_node) help_line[0]=@| + ("Perhaps you can make the output routine do it."); + error(); + } +} + +@ @<Put each...@>= +primitive("unpenalty", remove_item, penalty_node);@/ +@!@:un\_penalty\_}{\.{\\unpenalty} primitive@> +primitive("unkern", remove_item, kern_node);@/ +@!@:un\_kern\_}{\.{\\unkern} primitive@> +primitive("unskip", remove_item, glue_node);@/ +@!@:un\_skip\_}{\.{\\unskip} primitive@> +primitive("unhbox", un_hbox, box_code);@/ +@!@:un\_hbox\_}{\.{\\unhbox} primitive@> +primitive("unhcopy", un_hbox, copy_code);@/ +@!@:un\_hcopy\_}{\.{\\unhcopy} primitive@> +primitive("unvbox", un_vbox, box_code);@/ +@!@:un\_vbox\_}{\.{\\unvbox} primitive@> +primitive("unvcopy", un_vbox, copy_code);@/ +@!@:un\_vcopy\_}{\.{\\unvcopy} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case remove_item: if (chr_code==glue_node) print_esc("unskip"); + else if (chr_code==kern_node) print_esc("unkern"); + else print_esc("unpenalty");@+break; +case un_hbox: if (chr_code==copy_code) print_esc("unhcopy"); + else print_esc("unhbox");@+break; +case un_vbox: if (chr_code==copy_code) print_esc("unvcopy"); + else print_esc("unvbox");@+break; + +@ The |un_hbox| and |un_vbox| commands unwrap one of the 256 current boxes. + +@<Cases of |main_control| that build...@>= +case vmode+un_vbox: case hmode+un_hbox: case mmode+un_hbox: unpackage();@+break; + +@ @<Declare act...@>= +static void unpackage(void) +{@+ +pointer p; /*the box*/ +int @!c; /*should we copy?*/ +c=cur_chr;scan_register_num();fetch_box(p); +if (p==null) return; +if ((abs(mode)==mmode)||@| + ((abs(mode)==vmode)&& (type(p)!=vlist_node) + && (type(p)!=whatsit_node || (subtype(p)!=vset_node + && subtype(p)!=vpack_node))) ||@| + ((abs(mode)==hmode)&& (type(p)!=hlist_node) + && (type(p)!=whatsit_node || ( subtype(p)!=hset_node + && subtype(p)!=hpack_node)))) + {@+print_err("Incompatible list can't be unboxed"); +@.Incompatible list...@> + help3("Sorry, Pandora. (You sneaky devil.)",@/ + "I refuse to unbox an \\hbox in vertical mode or vice versa.",@/ + "And I can't open any boxes in math mode.");@/ + error();return; + } +if (c==copy_code) link(tail)=copy_node_list(list_ptr(p)); +else{@+link(tail)=list_ptr(p);change_box(null); + list_ptr(p)=null;flush_node_list(p); + } +while (link(tail)!=null) tail=link(tail); +} + +@ @<Forbidden...@>=case vmode+ital_corr: + +@ Italic corrections are converted to kern nodes when the |ital_corr| command +follows a character. In math mode the same effect is achieved by appending +a kern of zero here, since italic corrections are supplied later. + +@<Cases of |main_control| that build...@>= +case hmode+ital_corr: append_italic_correction();@+break; +case mmode+ital_corr: tail_append(new_kern(0))@;@+break; + +@ @<Declare act...@>= +static void append_italic_correction(void) +{@+ +pointer p; /*|char_node| at the tail of the current list*/ +internal_font_number @!f; /*the font in the |char_node|*/ +if (tail!=head) + {@+if (is_char_node(tail)) p=tail; + else if (type(tail)==ligature_node) p=lig_char(tail); + else return; + f=font(p); + tail_append(new_kern(char_italic(f, char_info(f, character(p))))); + subtype(tail)=explicit; + } +} + +@ Discretionary nodes are easy in the common case `\.{\\-}', but in the +general case we must process three braces full of items. + +@<Put each...@>= +primitive("-", discretionary, 1); +@!@:Single-character primitives -}{\quad\.{\\-}@> +primitive("discretionary", discretionary, 0); +@!@:discretionary\_}{\.{\\discretionary} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case discretionary: if (chr_code==1) + print_esc("-");@+else print_esc("discretionary");@+break; + +@ @<Cases of |main_control| that build...@>= +case hmode+discretionary: case mmode+discretionary: append_discretionary();@+break; + +@ The space factor does not change when we append a discretionary node, +but it starts out as 1000 in the subsidiary lists. + +@<Declare act...@>= +static void append_discretionary(void) +{@+int c; /*hyphen character*/ +tail_append(new_disc()); +if (cur_chr==1) + {@+c=hyphen_char[cur_font]; + if (c >= 0) if (c < 256) pre_break(tail)=new_character(cur_font, c); + } +else{@+incr(save_ptr);saved(-1)=0;new_save_level(disc_group); + scan_left_brace();push_nest();mode=-hmode;space_factor=1000; + } +} + +@ The three discretionary lists are constructed somewhat as if they were +hboxes. A~subroutine called |build_discretionary| handles the transitions. +(This is sort of fun.) + +@<Cases of |handle...@>= +case disc_group: build_discretionary();@+break; + +@ @<Declare act...@>= +static void build_discretionary(void) +{@+ +pointer p, @!q; /*for link manipulation*/ +int @!n; /*length of discretionary list*/ +unsave(); +@<Prune the current list, if necessary, until it contains only |char_node|, |kern_node|, +|hlist_node|, |vlist_node|, |rule_node|, and |ligature_node| items; set |n| to the +length of the list, and set |q| to the list's tail@>; +p=link(head);pop_nest(); +switch (saved(-1)) { +case 0: pre_break(tail)=p;@+break; +case 1: post_break(tail)=p;@+break; +case 2: @<Attach list |p| to the current list, and record its length; then finish +up and |return|@>; +} /*there are no other cases*/ +incr(saved(-1));new_save_level(disc_group);scan_left_brace(); +push_nest();mode=-hmode;space_factor=1000; +} + +@ @<Attach list |p| to the current...@>= +{@+if ((n > 0)&&(abs(mode)==mmode)) + {@+print_err("Illegal math ");print_esc("discretionary"); +@.Illegal math \\disc...@> + help2("Sorry: The third part of a discretionary break must be",@/ + "empty, in math formulas. I had to delete your third part."); + flush_node_list(p);n=0;error(); + } +else link(tail)=p; +if (n <= 0x7F) set_replace_count(tail,n); +else{@+print_err("Discretionary list is too long"); +@.Discretionary list is too long@> + help2("Wow---I never thought anybody would tweak me here.",@/ + "You can't seriously need such a huge discretionary list?"); + error(); + } +if (n > 0) tail=q; +decr(save_ptr);return; +} + +@ During this loop, |p==link(q)| and there are |n| items preceding |p|. + +@<Prune the current list, if necessary...@>= +q=head;p=link(q);n=0; +while (p!=null) + {@+if (!is_char_node(p)) if (type(p) > rule_node) + if (type(p)!=kern_node) if (type(p)!=ligature_node) + {@+print_err("Improper discretionary list"); +@.Improper discretionary list@> + help1("Discretionary lists must contain only boxes and kerns.");@/ + error(); + begin_diagnostic(); + print_nl("The following discretionary sublist has been deleted:"); +@.The following...deleted@> + show_box(p); + end_diagnostic(true); + flush_node_list(p);link(q)=null;goto done; + } + q=p;p=link(q);incr(n); + } +done: + +@ We need only one more thing to complete the horizontal mode routines, namely +the \.{\\accent} primitive. + +@<Cases of |main_control| that build...@>= +case hmode+accent: make_accent();@+break; + +@ The positioning of accents is straightforward but tedious. Given an accent +of width |a|, designed for characters of height |x| and slant |s|; +and given a character of width |w|, height |h|, and slant |t|: We will shift +the accent down by |x-h|, and we will insert kern nodes that have the effect of +centering the accent over the character and shifting the accent to the +right by $\delta={1\over2}(w-a)+h\cdot t-x\cdot s$. If either character is +absent from the font, we will simply use the other, without shifting. + +@<Declare act...@>= +static void make_accent(void) +{@+double s, @!t; /*amount of slant*/ +pointer @!p, @!q, @!r; /*character, box, and kern nodes*/ +internal_font_number @!f; /*relevant font*/ +scaled @!a, @!h, @!x, @!w, @!delta; /*heights and widths, as explained above*/ +four_quarters @!i; /*character information*/ +scan_char_num();f=cur_font;p=new_character(f, cur_val); +if (p!=null) + {@+x=x_height(f);s=slant(f)/float_constant(65536); +@^real division@> + a=char_width(f, char_info(f, character(p)));@/ + do_assignments();@/ + @<Create a character node |q| for the next character, but set |q:=null| if problems +arise@>; + if (q!=null) @<Append the accent with appropriate kerns, then set |p:=q|@>; + link(tail)=p;tail=p;space_factor=1000; + } +} + +@ @<Create a character node |q| for the next...@>= +q=null;f=cur_font; +if ((cur_cmd==letter)||(cur_cmd==other_char)||(cur_cmd==char_given)) + q=new_character(f, cur_chr); +else if (cur_cmd==char_num) + {@+scan_char_num();q=new_character(f, cur_val); + } +else back_input() + +@ The kern nodes appended here must be distinguished from other kerns, lest +they be wiped away by the hyphenation algorithm or by a previous line break. + +The two kerns are computed with (machine-dependent) |double| arithmetic, but +their sum is machine-independent; the net effect is machine-independent, +because the user cannot remove these nodes nor access them via \.{\\lastkern}. + +@<Append the accent with appropriate kerns...@>= +{@+t=slant(f)/float_constant(65536); +@^real division@> +i=char_info(f, character(q)); +w=char_width(f, i);h=char_height(f, height_depth(i)); +if (h!=x) /*the accent must be shifted up or down*/ + {@+p=hpack(p, natural);shift_amount(p)=x-h; + } +delta=round((w-a)/float_constant(2)+h*t-x*s); +@^real multiplication@> +@^real addition@> +r=new_kern(delta);subtype(r)=acc_kern;link(tail)=r;link(r)=p; +tail=new_kern(-a-delta);subtype(tail)=acc_kern;link(p)=tail;p=q; +} + +@ When `\.{\\cr}' or `\.{\\span}' or a tab mark comes through the scanner +into |main_control|, it might be that the user has foolishly inserted +one of them into something that has nothing to do with alignment. But it is +far more likely that a left brace or right brace has been omitted, since +|get_next| takes actions appropriate to alignment only when `\.{\\cr}' +or `\.{\\span}' or tab marks occur with |align_state==0|. The following +program attempts to make an appropriate recovery. + +@<Cases of |main_control| that build...@>= +any_mode(car_ret): any_mode(tab_mark): align_error();@+break; +any_mode(no_align): no_align_error();@+break; +any_mode(omit): omit_error();@+break; + +@ @<Declare act...@>= +static void align_error(void) +{@+if (abs(align_state) > 2) + @<Express consternation over the fact that no alignment is in progress@>@; +else{@+back_input(); + if (align_state < 0) + {@+print_err("Missing { inserted"); +@.Missing \{ inserted@> + incr(align_state);cur_tok=left_brace_token+'{'; + } + else{@+print_err("Missing } inserted"); +@.Missing \} inserted@> + decr(align_state);cur_tok=right_brace_token+'}'; + } + help3("I've put in what seems to be necessary to fix",@/ + "the current column of the current alignment.",@/ + "Try to go on, since this might almost work.");ins_error(); + } +} + +@ @<Express consternation...@>= +{@+print_err("Misplaced ");print_cmd_chr(cur_cmd, cur_chr); +@.Misplaced \&@> +@.Misplaced \\span@> +@.Misplaced \\cr@> +if (cur_tok==tab_token+'&') + {@+help6("I can't figure out why you would want to use a tab mark",@/ + "here. If you just want an ampersand, the remedy is",@/ + "simple: Just type `I\\&' now. But if some right brace",@/ + "up above has ended a previous alignment prematurely,",@/ + "you're probably due for more error messages, and you",@/ + "might try typing `S' now just to see what is salvageable."); + } +else{@+help5("I can't figure out why you would want to use a tab mark",@/ + "or \\cr or \\span just now. If something like a right brace",@/ + "up above has ended a previous alignment prematurely,",@/ + "you're probably due for more error messages, and you",@/ + "might try typing `S' now just to see what is salvageable."); + } +error(); +} + +@ The help messages here contain a little white lie, since \.{\\noalign} +and \.{\\omit} are allowed also after `\.{\\noalign\{...\}}'. + +@<Declare act...@>= +static void no_align_error(void) +{@+print_err("Misplaced ");print_esc("noalign"); +@.Misplaced \\noalign@> +help2("I expect to see \\noalign only after the \\cr of",@/ + "an alignment. Proceed, and I'll ignore this case.");error(); +} +static void omit_error(void) +{@+print_err("Misplaced ");print_esc("omit"); +@.Misplaced \\omit@> +help2("I expect to see \\omit only after tab marks or the \\cr of",@/ + "an alignment. Proceed, and I'll ignore this case.");error(); +} + +@ We've now covered most of the abuses of \.{\\halign} and \.{\\valign}. +Let's take a look at what happens when they are used correctly. + +@<Cases of |main_control| that build...@>= +case vmode+halign: case hmode+valign: init_align();@+break; +case mmode+halign: if (privileged()) + if (cur_group==math_shift_group) init_align(); + else off_save();@+break; +case vmode+endv: case hmode+endv: do_endv();@+break; + +@ An |align_group| code is supposed to remain on the |save_stack| +during an entire alignment, until |fin_align| removes it. + +A devious user might force an |endv| command to occur just about anywhere; +we must defeat such hacks. + +@<Declare act...@>= +static void do_endv(void) +{@+base_ptr=input_ptr;input_stack[base_ptr]=cur_input; +while ((input_stack[base_ptr].index_field!=v_template)&& + (input_stack[base_ptr].loc_field==null)&& + (input_stack[base_ptr].state_field==token_list)) decr(base_ptr); +if ((input_stack[base_ptr].index_field!=v_template)|| + (input_stack[base_ptr].loc_field!=null)|| + (input_stack[base_ptr].state_field!=token_list)) + fatal_error("(interwoven alignment preambles are not allowed)"); +@.interwoven alignment preambles...@> + if (cur_group==align_group) + {@+end_graf(); + if (fin_col()) fin_row(); + } +else off_save(); +} + +@ @<Cases of |handle_right_brace|...@>= +case align_group: {@+back_input();cur_tok=cs_token_flag+frozen_cr; + print_err("Missing ");print_esc("cr");print(" inserted"); +@.Missing \\cr inserted@> + help1("I'm guessing that you meant to end an alignment here."); + ins_error(); + } @+break; + +@ @<Cases of |handle_right_brace|...@>= +case no_align_group: {@+end_graf();unsave();align_peek(); + } @+break; + +@ Finally, \.{\\endcsname} is not supposed to get through to |main_control|. + +@<Cases of |main_control| that build...@>= +any_mode(end_cs_name): cs_error();@+break; + +@ @<Declare act...@>= +static void cs_error(void) +{@+print_err("Extra ");print_esc("endcsname"); +@.Extra \\endcsname@> +help1("I'm ignoring this, since I wasn't doing a \\csname."); +error(); +} + +@* Building math lists. +The routines that \TeX\ uses to create mlists are similar to those we have +just seen for the generation of hlists and vlists. But it is necessary to +make ``noads'' as well as nodes, so the reader should review the +discussion of math mode data structures before trying to make sense out of +the following program. + +Here is a little routine that needs to be done whenever a subformula +is about to be processed. The parameter is a code like |math_group|. + +@<Declare act...@>= +static void push_math(group_code @!c) +{@+push_nest();mode=-mmode;incompleat_noad=null;new_save_level(c); +} + +@ We get into math mode from horizontal mode when a `\.\$' (i.e., a +|math_shift| character) is scanned. We must check to see whether this +`\.\$' is immediately followed by another, in case display math mode is +called for. + +@<Cases of |main_control| that build...@>= +case hmode+math_shift: init_math();@+break; + +@ @<Declare act...@>= +static void init_math(void) +{@+ +scaled w; /*new or partial |pre_display_size|*/ +scaled @!l; /*new |display_width|*/ +scaled @!s; /*new |display_indent|*/ +pointer @!p; /*current node when calculating |pre_display_size|*/ +pointer @!q; /*glue specification when calculating |pre_display_size|*/ +internal_font_number @!f; /*font in current |char_node|*/ +int @!n; /*scope of paragraph shape specification*/ +scaled @!v; /*|w| plus possible glue amount*/ +scaled @!d; /*increment to |v|*/ +get_token(); /*|get_x_token| would fail on \.{\\ifmmode}\thinspace!*/ +if ((cur_cmd==math_shift)&&(mode > 0)) @<Go into display math mode@>@; +else{@+back_input();@<Go into ordinary math mode@>; + } +} + +@ @<Go into ordinary math mode@>= +{@+push_math(math_shift_group);eq_word_define(int_base+cur_fam_code,-1); +if (every_math!=null) begin_token_list(every_math, every_math_text); +} + +@ We get into ordinary math mode from display math mode when `\.{\\eqno}' or +`\.{\\leqno}' appears. In such cases |cur_chr| will be 0 or~1, respectively; +the value of |cur_chr| is placed onto |save_stack| for safe keeping. + +@<Cases of |main_control| that build...@>= +case mmode+eq_no: if (privileged()) + if (cur_group==math_shift_group) start_eq_no(); + else off_save();@+break; + +@ @<Put each...@>= +primitive("eqno", eq_no, 0); +@!@:eq\_no\_}{\.{\\eqno} primitive@> +primitive("leqno", eq_no, 1); +@!@:leq\_no\_}{\.{\\leqno} primitive@> + +@ When \TeX\ is in display math mode, |cur_group==math_shift_group|, +so it is not necessary for the |start_eq_no| procedure to test for +this condition. + +@<Declare act...@>= +static void start_eq_no(void) +{@+saved(0)=cur_chr;incr(save_ptr); +@<Go into ordinary math mode@>; +} + +@ @<Cases of |print_cmd_chr|...@>= +case eq_no: if (chr_code==1) print_esc("leqno");@+else print_esc("eqno");@+break; + +@ @<Forbidden...@>=non_math(eq_no): + +@ When we enter display math mode, we need to call |line_break| to +process the partial paragraph that has just been interrupted by the +display. Then we can set the proper values of |display_width| and +|display_indent| and |pre_display_size|. + +@<Go into display math mode@>= +{ if (head!=tail && !(type(tail)==whatsit_node && subtype(tail)==disp_node)) + { if (is_char_node(tail)) tail_append(new_penalty(inf_penalty))@; + else if (type(tail)!=glue_node) tail_append(new_penalty(inf_penalty))@; + else + {@+type(tail)=penalty_node;delete_glue_ref(glue_ptr(tail)); + flush_node_list(leader_ptr(tail));penalty(tail)=inf_penalty; + } + tail_append(new_param_glue(par_fill_skip_code)); + } +push_math(math_shift_group);mode=mmode; +eq_word_define(int_base+cur_fam_code,-1);@/ +if (every_display!=null) begin_token_list(every_display, every_display_text); +} + +@ @<Calculate the natural width, |w|, by which...@>= +v=shift_amount(just_box)+2*quad(cur_font);w=-max_dimen; +p=list_ptr(just_box); +while (p!=null) + {@+@<Let |d| be the natural width of node |p|; if the node is ``visible,'' |goto +found|; if the node is glue that stretches or shrinks, set |v:=max_dimen|@>; + if (v < max_dimen) v=v+d; + goto not_found; + found: if (v < max_dimen) + {@+v=v+d;w=v; + } + else{@+w=max_dimen;goto done; + } + not_found: p=link(p); + } +done: + +@ @<Let |d| be the natural width of node |p|...@>= +reswitch: if (is_char_node(p)) + {@+f=font(p);d=char_width(f, char_info(f, character(p))); + goto found; + } +switch (type(p)) { +case hlist_node: case vlist_node: case rule_node: {@+d=width(p);goto found; + } +case ligature_node: @<Make node |p| look like a |char_node|...@>@; +case kern_node: case math_node: d=width(p);@+break; +case glue_node: @<Let |d| be the natural width of this glue; if stretching or shrinking, +set |v:=max_dimen|; |goto found| in the case of leaders@>@;@+break; +case whatsit_node: @<Let |d| be the width of the whatsit |p|@>;@+break; +default:d=0; +} + +@ We need to be careful that |w|, |v|, and |d| do not depend on any |glue_set| +values, since such values are subject to system-dependent rounding. +System-dependent numbers are not allowed to infiltrate parameters like +|pre_display_size|, since \TeX82 is supposed to make the same decisions on all +machines. + +@<Let |d| be the natural width of this glue...@>= +{@+q=glue_ptr(p);d=width(q); +if (glue_sign(just_box)==stretching) + {@+if ((glue_order(just_box)==stretch_order(q))&&@| + (stretch(q)!=0)) + v=max_dimen; + } +else if (glue_sign(just_box)==shrinking) + {@+if ((glue_order(just_box)==shrink_order(q))&&@| + (shrink(q)!=0)) + v=max_dimen; + } +if (subtype(p) >= a_leaders) goto found; +} + +@ A displayed equation is considered to be three lines long, so we +calculate the length and offset of line number |prev_graf+2|. + +@<Calculate the length, |l|,...@>= +if (par_shape_ptr==null) + if ((hang_indent!=0)&&@| + (((hang_after >= 0)&&(prev_graf+2 > hang_after))||@| + (prev_graf+1 < -hang_after))) + {@+l=hsize-abs(hang_indent); + if (hang_indent > 0) s=hang_indent;@+else s=0; + } + else{@+l=hsize;s=0; + } +else{@+n=info(par_shape_ptr); + if (prev_graf+2 >= n) p=par_shape_ptr+2*n; + else p=par_shape_ptr+2*(prev_graf+2); + s=mem[p-1].sc;l=mem[p].sc; + } + +@ Subformulas of math formulas cause a new level of math mode to be entered, +on the semantic nest as well as the save stack. These subformulas arise in +several ways: (1)~A left brace by itself indicates the beginning of a +subformula that will be put into a box, thereby freezing its glue and +preventing line breaks. (2)~A subscript or superscript is treated as a +subformula if it is not a single character; the same applies to +the nucleus of things like \.{\\underline}. (3)~The \.{\\left} primitive +initiates a subformula that will be terminated by a matching \.{\\right}. +The group codes placed on |save_stack| in these three cases are +|math_group|, |math_group|, and |math_left_group|, respectively. + +Here is the code that handles case (1); the other cases are not quite as +trivial, so we shall consider them later. + +@<Cases of |main_control| that build...@>= +case mmode+left_brace: {@+tail_append(new_noad()); + back_input();scan_math(nucleus(tail)); + } @+break; + +@ Recall that the |nucleus|, |subscr|, and |supscr| fields in a noad are +broken down into subfields called |math_type| and either |info| or +|(fam, character)|. The job of |scan_math| is to figure out what to place +in one of these principal fields; it looks at the subformula that +comes next in the input, and places an encoding of that subformula +into a given word of |mem|. + +@d fam_in_range ((cur_fam >= 0)&&(cur_fam < 16)) + +@<Declare act...@>= +static void scan_math(pointer @!p) +{@+ +int c; /*math character code*/ +restart: @<Get the next non-blank non-relax...@>; +reswitch: switch (cur_cmd) { +case letter: case other_char: case char_given: {@+c=ho(math_code(cur_chr)); + if (c==0100000) + {@+@<Treat |cur_chr| as an active character@>; + goto restart; + } + } @+break; +case char_num: {@+scan_char_num();cur_chr=cur_val;cur_cmd=char_given; + goto reswitch; + } +case math_char_num: {@+scan_fifteen_bit_int();c=cur_val; + } @+break; +case math_given: c=cur_chr;@+break; +case delim_num: {@+scan_twenty_seven_bit_int();c=cur_val/010000; + } @+break; +default:@<Scan a subformula enclosed in braces and |return|@>@; +} @/ +math_type(p)=math_char;character(p)=qi(c%256); +if ((c >= var_code)&&fam_in_range) fam(p)=cur_fam; +else fam(p)=(c/256)%16; +} + +@ An active character that is an |outer_call| is allowed here. + +@<Treat |cur_chr|...@>= +{@+cur_cs=cur_chr+active_base; +cur_cmd=eq_type(cur_cs);cur_chr=equiv(cur_cs); +x_token();back_input(); +} + +@ The pointer |p| is placed on |save_stack| while a complex subformula +is being scanned. + +@<Scan a subformula...@>= +{@+back_input();scan_left_brace();@/ +saved(0)=p;incr(save_ptr);push_math(math_group);return; +} + +@ The simplest math formula is, of course, `\.{\${ }\$}', when no noads are +generated. The next simplest cases involve a single character, e.g., +`\.{\$x\$}'. Even though such cases may not seem to be very interesting, +the reader can perhaps understand how happy the author was when `\.{\$x\$}' +was first properly typeset by \TeX. The code in this section was used. +@^Knuth, Donald Ervin@> + +@<Cases of |main_control| that build...@>= +case mmode+letter: case mmode+other_char: case mmode+char_given: + set_math_char(ho(math_code(cur_chr)));@+break; +case mmode+char_num: {@+scan_char_num();cur_chr=cur_val; + set_math_char(ho(math_code(cur_chr))); + } @+break; +case mmode+math_char_num: {@+scan_fifteen_bit_int();set_math_char(cur_val); + } @+break; +case mmode+math_given: set_math_char(cur_chr);@+break; +case mmode+delim_num: {@+scan_twenty_seven_bit_int(); + set_math_char(cur_val/010000); + } @+break; + +@ The |set_math_char| procedure creates a new noad appropriate to a given +math code, and appends it to the current mlist. However, if the math code +is sufficiently large, the |cur_chr| is treated as an active character and +nothing is appended. + +@<Declare act...@>= +static void set_math_char(int @!c) +{@+pointer p; /*the new noad*/ +if (c >= 0100000) + @<Treat |cur_chr|...@>@; +else{@+p=new_noad();math_type(nucleus(p))=math_char; + character(nucleus(p))=qi(c%256); + fam(nucleus(p))=(c/256)%16; + if (c >= var_code) + {@+if (fam_in_range) fam(nucleus(p))=cur_fam; + type(p)=ord_noad; + } + else type(p)=ord_noad+(c/010000); + link(tail)=p;tail=p; + } +} + +@ Primitive math operators like \.{\\mathop} and \.{\\underline} are given +the command code |math_comp|, supplemented by the noad type that they +generate. + +@<Put each...@>= +primitive("mathord", math_comp, ord_noad); +@!@:math\_ord\_}{\.{\\mathord} primitive@> +primitive("mathop", math_comp, op_noad); +@!@:math\_op\_}{\.{\\mathop} primitive@> +primitive("mathbin", math_comp, bin_noad); +@!@:math\_bin\_}{\.{\\mathbin} primitive@> +primitive("mathrel", math_comp, rel_noad); +@!@:math\_rel\_}{\.{\\mathrel} primitive@> +primitive("mathopen", math_comp, open_noad); +@!@:math\_open\_}{\.{\\mathopen} primitive@> +primitive("mathclose", math_comp, close_noad); +@!@:math\_close\_}{\.{\\mathclose} primitive@> +primitive("mathpunct", math_comp, punct_noad); +@!@:math\_punct\_}{\.{\\mathpunct} primitive@> +primitive("mathinner", math_comp, inner_noad); +@!@:math\_inner\_}{\.{\\mathinner} primitive@> +primitive("underline", math_comp, under_noad); +@!@:underline\_}{\.{\\underline} primitive@> +primitive("overline", math_comp, over_noad);@/ +@!@:overline\_}{\.{\\overline} primitive@> +primitive("displaylimits", limit_switch, normal); +@!@:display\_limits\_}{\.{\\displaylimits} primitive@> +primitive("limits", limit_switch, limits); +@!@:limits\_}{\.{\\limits} primitive@> +primitive("nolimits", limit_switch, no_limits); +@!@:no\_limits\_}{\.{\\nolimits} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case math_comp: switch (chr_code) { + case ord_noad: print_esc("mathord");@+break; + case op_noad: print_esc("mathop");@+break; + case bin_noad: print_esc("mathbin");@+break; + case rel_noad: print_esc("mathrel");@+break; + case open_noad: print_esc("mathopen");@+break; + case close_noad: print_esc("mathclose");@+break; + case punct_noad: print_esc("mathpunct");@+break; + case inner_noad: print_esc("mathinner");@+break; + case under_noad: print_esc("underline");@+break; + default:print_esc("overline"); + } @+break; +case limit_switch: if (chr_code==limits) print_esc("limits"); + else if (chr_code==no_limits) print_esc("nolimits"); + else print_esc("displaylimits");@+break; + +@ @<Cases of |main_control| that build...@>= +case mmode+math_comp: {@+tail_append(new_noad()); + type(tail)=cur_chr;scan_math(nucleus(tail)); + } @+break; +case mmode+limit_switch: math_limit_switch();@+break; + +@ @<Declare act...@>= +static void math_limit_switch(void) +{@+ +if (head!=tail) if (type(tail)==op_noad) + {@+subtype(tail)=cur_chr;return; + } +print_err("Limit controls must follow a math operator"); +@.Limit controls must follow...@> +help1("I'm ignoring this misplaced \\limits or \\nolimits command.");error(); +} + +@ Delimiter fields of noads are filled in by the |scan_delimiter| routine. +The first parameter of this procedure is the |mem| address where the +delimiter is to be placed; the second tells if this delimiter follows +\.{\\radical} or not. + +@<Declare act...@>= +static void scan_delimiter(pointer @!p, bool @!r) +{@+if (r) scan_twenty_seven_bit_int(); +else{@+@<Get the next non-blank non-relax...@>; + switch (cur_cmd) { + case letter: case other_char: cur_val=del_code(cur_chr);@+break; + case delim_num: scan_twenty_seven_bit_int();@+break; + default:cur_val=-1; + } + } +if (cur_val < 0) @<Report that an invalid delimiter code is being changed to null; +set~|cur_val:=0|@>; +small_fam(p)=(cur_val/04000000)%16; +small_char(p)=qi((cur_val/010000)%256); +large_fam(p)=(cur_val/256)%16; +large_char(p)=qi(cur_val%256); +} + +@ @<Report that an invalid delimiter...@>= +{@+print_err("Missing delimiter (. inserted)"); +@.Missing delimiter...@> +help6("I was expecting to see something like `(' or `\\{' or",@/ + "`\\}' here. If you typed, e.g., `{' instead of `\\{', you",@/ + "should probably delete the `{' by typing `1' now, so that",@/ + "braces don't get unbalanced. Otherwise just proceed.",@/ + "Acceptable delimiters are characters whose \\delcode is",@/ + "nonnegative, or you can use `\\delimiter <delimiter code>'."); +back_error();cur_val=0; +} + +@ @<Cases of |main_control| that build...@>= +case mmode+radical: math_radical();@+break; + +@ @<Declare act...@>= +static void math_radical(void) +{@+tail_append(get_node(radical_noad_size)); +type(tail)=radical_noad;subtype(tail)=normal; +mem[nucleus(tail)].hh=empty_field; +mem[subscr(tail)].hh=empty_field; +mem[supscr(tail)].hh=empty_field; +scan_delimiter(left_delimiter(tail), true);scan_math(nucleus(tail)); +} + +@ @<Cases of |main_control| that build...@>= +case mmode+accent: case mmode+math_accent: math_ac();@+break; + +@ @<Declare act...@>= +static void math_ac(void) +{@+if (cur_cmd==accent) + @<Complain that the user should have said \.{\\mathaccent}@>; +tail_append(get_node(accent_noad_size)); +type(tail)=accent_noad;subtype(tail)=normal; +mem[nucleus(tail)].hh=empty_field; +mem[subscr(tail)].hh=empty_field; +mem[supscr(tail)].hh=empty_field; +math_type(accent_chr(tail))=math_char; +scan_fifteen_bit_int(); +character(accent_chr(tail))=qi(cur_val%256); +if ((cur_val >= var_code)&&fam_in_range) fam(accent_chr(tail))=cur_fam; +else fam(accent_chr(tail))=(cur_val/256)%16; +scan_math(nucleus(tail)); +} + +@ @<Complain that the user should have said \.{\\mathaccent}@>= +{@+print_err("Please use ");print_esc("mathaccent"); +print(" for accents in math mode"); +@.Please use \\mathaccent...@> +help2("I'm changing \\accent to \\mathaccent here; wish me luck.",@/ + "(Accents are not the same in formulas as they are in text.)"); +error(); +} + +@ @<Cases of |main_control| that build...@>= +case mmode+vcenter: {@+scan_spec(vcenter_group, false);normal_paragraph(); + push_nest();mode=-vmode;prev_depth=ignore_depth; + if (every_vbox!=null) begin_token_list(every_vbox, every_vbox_text); + } @+break; + +@ @<Cases of |handle...@>= +case vcenter_group: {@+end_graf();unsave();save_ptr=save_ptr-2; + p=vpack(link(head), saved(1), saved_hfactor(1), saved_vfactor(1), saved(0));pop_nest(); + tail_append(new_noad());type(tail)=vcenter_noad; + math_type(nucleus(tail))=sub_box;info(nucleus(tail))=p; + } @+break; + +@ The routine that inserts a |style_node| holds no surprises. + +@<Put each...@>= +primitive("displaystyle", math_style, display_style); +@!@:display\_style\_}{\.{\\displaystyle} primitive@> +primitive("textstyle", math_style, text_style); +@!@:text\_style\_}{\.{\\textstyle} primitive@> +primitive("scriptstyle", math_style, script_style); +@!@:script\_style\_}{\.{\\scriptstyle} primitive@> +primitive("scriptscriptstyle", math_style, script_script_style); +@!@:script\_script\_style\_}{\.{\\scriptscriptstyle} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case math_style: print_style(chr_code);@+break; + +@ @<Cases of |main_control| that build...@>= +case mmode+math_style: tail_append(new_style(cur_chr))@;@+break; +case mmode+non_script: {@+tail_append(new_glue(zero_glue)); + subtype(tail)=cond_math_glue; + } @+break; +case mmode+math_choice: append_choices();@+break; + +@ The routine that scans the four mlists of a \.{\\mathchoice} is very +much like the routine that builds discretionary nodes. + +@<Declare act...@>= +static void append_choices(void) +{@+tail_append(new_choice());incr(save_ptr);saved(-1)=0; +push_math(math_choice_group);scan_left_brace(); +} + +@ @<Cases of |handle_right_brace|...@>= +case math_choice_group: build_choices();@+break; + +@ @<Declare act...@>= +@t\4@>@<Declare the function called |fin_mlist|@>@t@>@;@/ +static void build_choices(void) +{@+ +pointer p; /*the current mlist*/ +unsave();p=fin_mlist(null); +switch (saved(-1)) { +case 0: display_mlist(tail)=p;@+break; +case 1: text_mlist(tail)=p;@+break; +case 2: script_mlist(tail)=p;@+break; +case 3: {@+script_script_mlist(tail)=p;decr(save_ptr);return; + } +} /*there are no other cases*/ +incr(saved(-1));push_math(math_choice_group);scan_left_brace(); +} + +@ Subscripts and superscripts are attached to the previous nucleus by the +@^superscripts@>@^subscripts@> +action procedure called |sub_sup|. We use the facts that |sub_mark==sup_mark+1| +and |subscr(p)==supscr(p)+1|. + +@<Cases of |main_control| that build...@>= +case mmode+sub_mark: case mmode+sup_mark: sub_sup();@+break; + +@ @<Declare act...@>= +static void sub_sup(void) +{@+small_number t; /*type of previous sub/superscript*/ +pointer @!p; /*field to be filled by |scan_math|*/ +t=empty;p=null; +if (tail!=head) if (scripts_allowed(tail)) + {@+p=supscr(tail)+cur_cmd-sup_mark; /*|supscr| or |subscr|*/ + t=math_type(p); + } +if ((p==null)||(t!=empty)) @<Insert a dummy noad to be sub/superscripted@>; +scan_math(p); +} + +@ @<Insert a dummy...@>= +{@+tail_append(new_noad()); +p=supscr(tail)+cur_cmd-sup_mark; /*|supscr| or |subscr|*/ +if (t!=empty) + {@+if (cur_cmd==sup_mark) + {@+print_err("Double superscript"); +@.Double superscript@> + help1("I treat `x^1^2' essentially like `x^1{}^2'."); + } + else{@+print_err("Double subscript"); +@.Double subscript@> + help1("I treat `x_1_2' essentially like `x_1{}_2'."); + } + error(); + } +} + +@ An operation like `\.{\\over}' causes the current mlist to go into a +state of suspended animation: |incompleat_noad| points to a |fraction_noad| +that contains the mlist-so-far as its numerator, while the denominator +is yet to come. Finally when the mlist is finished, the denominator will +go into the incompleat fraction noad, and that noad will become the +whole formula, unless it is surrounded by `\.{\\left}' and `\.{\\right}' +delimiters. + +@d above_code 0 /* `\.{\\above}' */ +@d over_code 1 /* `\.{\\over}' */ +@d atop_code 2 /* `\.{\\atop}' */ +@d delimited_code 3 /* `\.{\\abovewithdelims}', etc.*/ + +@<Put each...@>= +primitive("above", above, above_code);@/ +@!@:above\_}{\.{\\above} primitive@> +primitive("over", above, over_code);@/ +@!@:over\_}{\.{\\over} primitive@> +primitive("atop", above, atop_code);@/ +@!@:atop\_}{\.{\\atop} primitive@> +primitive("abovewithdelims", above, delimited_code+above_code);@/ +@!@:above\_with\_delims\_}{\.{\\abovewithdelims} primitive@> +primitive("overwithdelims", above, delimited_code+over_code);@/ +@!@:over\_with\_delims\_}{\.{\\overwithdelims} primitive@> +primitive("atopwithdelims", above, delimited_code+atop_code); +@!@:atop\_with\_delims\_}{\.{\\atopwithdelims} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case above: switch (chr_code) { + case over_code: print_esc("over");@+break; + case atop_code: print_esc("atop");@+break; + case delimited_code+above_code: print_esc("abovewithdelims");@+break; + case delimited_code+over_code: print_esc("overwithdelims");@+break; + case delimited_code+atop_code: print_esc("atopwithdelims");@+break; + default:print_esc("above"); + } @+break; + +@ @<Cases of |main_control| that build...@>= +case mmode+above: math_fraction();@+break; + +@ @<Declare act...@>= +static void math_fraction(void) +{@+small_number c; /*the type of generalized fraction we are scanning*/ +c=cur_chr; +if (incompleat_noad!=null) + @<Ignore the fraction operation and complain about this ambiguous case@>@; +else{@+incompleat_noad=get_node(fraction_noad_size); + type(incompleat_noad)=fraction_noad; + subtype(incompleat_noad)=normal; + math_type(numerator(incompleat_noad))=sub_mlist; + info(numerator(incompleat_noad))=link(head); + mem[denominator(incompleat_noad)].hh=empty_field; + mem[left_delimiter(incompleat_noad)].qqqq=null_delimiter; + mem[right_delimiter(incompleat_noad)].qqqq=null_delimiter;@/ + link(head)=null;tail=head; + @<Use code |c| to distinguish between generalized fractions@>; + } +} + +@ @<Use code |c|...@>= +if (c >= delimited_code) + {@+scan_delimiter(left_delimiter(incompleat_noad), false); + scan_delimiter(right_delimiter(incompleat_noad), false); + } +switch (c%delimited_code) { +case above_code: {@+scan_normal_dimen; + thickness(incompleat_noad)=cur_val; + } @+break; +case over_code: thickness(incompleat_noad)=default_code;@+break; +case atop_code: thickness(incompleat_noad)=0; +} /*there are no other cases*/ + +@ @<Ignore the fraction...@>= +{@+if (c >= delimited_code) + {@+scan_delimiter(garbage, false);scan_delimiter(garbage, false); + } +if (c%delimited_code==above_code) scan_normal_dimen; +print_err("Ambiguous; you need another { and }"); +@.Ambiguous...@> +help3("I'm ignoring this fraction specification, since I don't",@/ + "know whether a construction like `x \\over y \\over z'",@/ + "means `{x \\over y} \\over z' or `x \\over {y \\over z}'."); +error(); +} + +@ At the end of a math formula or subformula, the |fin_mlist| routine is +called upon to return a pointer to the newly completed mlist, and to +pop the nest back to the enclosing semantic level. The parameter to +|fin_mlist|, if not null, points to a |right_noad| that ends the +current mlist; this |right_noad| has not yet been appended. + +@<Declare the function called |fin_mlist|@>= +static pointer fin_mlist(pointer @!p) +{@+pointer q; /*the mlist to return*/ +if (incompleat_noad!=null) @<Compleat the incompleat noad@>@; +else{@+link(tail)=p;q=link(head); + } +pop_nest();return q; +} + +@ @<Compleat...@>= +{@+math_type(denominator(incompleat_noad))=sub_mlist; +info(denominator(incompleat_noad))=link(head); +if (p==null) q=incompleat_noad; +else{@+q=info(numerator(incompleat_noad)); + if ((type(q)!=left_noad)||(delim_ptr==null)) confusion("right"); +@:this can't happen right}{\quad right@> + info(numerator(incompleat_noad))=link(delim_ptr); + link(delim_ptr)=incompleat_noad;link(incompleat_noad)=p; + } +} + +@ Now at last we're ready to see what happens when a right brace occurs +in a math formula. Two special cases are simplified here: Braces are effectively +removed when they surround a single Ord without sub/superscripts, or when they +surround an accent that is the nucleus of an Ord atom. + +@<Cases of |handle...@>= +case math_group: {@+unsave();decr(save_ptr);@/ + math_type(saved(0))=sub_mlist;p=fin_mlist(null);info(saved(0))=p; + if (p!=null) if (link(p)==null) + if (type(p)==ord_noad) + {@+if (math_type(subscr(p))==empty) + if (math_type(supscr(p))==empty) + {@+mem[saved(0)].hh=mem[nucleus(p)].hh; + free_node(p, noad_size); + } + } + else if (type(p)==accent_noad) if (saved(0)==nucleus(tail)) + if (type(tail)==ord_noad) @<Replace the tail of the list by |p|@>; + } @+break; + +@ @<Replace the tail...@>= +{@+q=head;while (link(q)!=tail) q=link(q); +link(q)=p;free_node(tail, noad_size);tail=p; +} + +@ We have dealt with all constructions of math mode except `\.{\\left}' and +`\.{\\right}', so the picture is completed by the following sections of +the program. + +@<Put each...@>= +primitive("left", left_right, left_noad); +@!@:left\_}{\.{\\left} primitive@> +primitive("right", left_right, right_noad); +@!@:right\_}{\.{\\right} primitive@> +text(frozen_right)=text(cur_val);eqtb[frozen_right]=eqtb[cur_val]; + +@ @<Cases of |print_cmd_chr|...@>= +case left_right: if (chr_code==left_noad) print_esc("left") +@/@<Cases of |left_right| for |print_cmd_chr|@>;@/ +else print_esc("right");@+break; + +@ @<Cases of |main_control| that build...@>= +case mmode+left_right: math_left_right();@+break; + +@ @<Declare act...@>= +static void math_left_right(void) +{@+small_number t; /*|left_noad| or |right_noad|*/ +pointer @!p; /*new noad*/ +pointer @!q; /*resulting mlist*/ +t=cur_chr; +if ((t!=left_noad)&&(cur_group!=math_left_group)) + @<Try to recover from mismatched \.{\\right}@>@; +else{@+p=new_noad();type(p)=t; + scan_delimiter(delimiter(p), false); + if (t==middle_noad) + {@+type(p)=right_noad;subtype(p)=middle_noad; + } + if (t==left_noad) q=p; + else{@+q=fin_mlist(p);unsave(); /*end of |math_left_group|*/ + } + if (t!=right_noad) + {@+push_math(math_left_group);link(head)=q;tail=p; + delim_ptr=p; + } + else{@+ + tail_append(new_noad());type(tail)=inner_noad; + math_type(nucleus(tail))=sub_mlist; + info(nucleus(tail))=q; + } + } +} + +@ @<Try to recover from mismatch...@>= +{@+if (cur_group==math_shift_group) + {@+scan_delimiter(garbage, false); + print_err("Extra "); + if (t==middle_noad) + {@+print_esc("middle"); +@.Extra \\middle.@> + help1("I'm ignoring a \\middle that had no matching \\left."); + } + else{@+print_esc("right"); +@.Extra \\right.@> + help1("I'm ignoring a \\right that had no matching \\left."); + } + error(); + } +else off_save(); +} + +@ Here is the only way out of math mode. + +@<Cases of |main_control| that build...@>= +case mmode+math_shift: if (cur_group==math_shift_group) after_math(); + else off_save();@+break; + +@ @<Declare act...@>= +static void after_math(void) +{@+bool l; /*`\.{\\leqno}' instead of `\.{\\eqno}'*/ +bool @!danger; /*not enough symbol fonts are present*/ +int @!m; /*|mmode| or |-mmode|*/ +pointer @!p; /*the formula*/ +pointer @!a; /*box containing equation number*/ +danger=false; +@<Check that the necessary fonts for math symbols are present; if not, flush the current +math lists and set |danger:=true|@>; +m=mode;l=false;p=fin_mlist(null); /*this pops the nest*/ +if (mode==-m) /*end of equation number*/ + {@+@<Check that another \.\$ follows@>; + cur_mlist=p;cur_style=text_style;mlist_penalties=false; + mlist_to_hlist();a=hpack(link(temp_head), natural); + unsave();decr(save_ptr); /*now |cur_group==math_shift_group|*/ + if (saved(0)==1) l=true; + danger=false; + @<Check that the necessary fonts for math symbols are present; if not, flush the +current math lists and set |danger:=true|@>; + m=mode;p=fin_mlist(null); + } +else a=null; +if (m < 0) @<Finish math in text@>@; +else{@+if (a==null) @<Check that another \.\$ follows@>; + @<Finish displayed math@>; + } +} + +@ @<Check that the necessary fonts...@>= +if ((font_params[fam_fnt(2+text_size)] < total_mathsy_params)||@| + (font_params[fam_fnt(2+script_size)] < total_mathsy_params)||@| + (font_params[fam_fnt(2+script_script_size)] < total_mathsy_params)) + {@+print_err("Math formula deleted: Insufficient symbol fonts");@/ +@.Math formula deleted...@> + help3("Sorry, but I can't typeset math unless \\textfont 2",@/ + "and \\scriptfont 2 and \\scriptscriptfont 2 have all",@/ + "the \\fontdimen values needed in math symbol fonts."); + error();flush_math();danger=true; + } +else if ((font_params[fam_fnt(3+text_size)] < total_mathex_params)||@| + (font_params[fam_fnt(3+script_size)] < total_mathex_params)||@| + (font_params[fam_fnt(3+script_script_size)] < total_mathex_params)) + {@+print_err("Math formula deleted: Insufficient extension fonts");@/ + help3("Sorry, but I can't typeset math unless \\textfont 3",@/ + "and \\scriptfont 3 and \\scriptscriptfont 3 have all",@/ + "the \\fontdimen values needed in math extension fonts."); + error();flush_math();danger=true; + } + +@ The |unsave| is done after everything else here; hence an appearance of +`\.{\\mathsurround}' inside of `\.{\$...\$}' affects the spacing at these +particular \.\$'s. This is consistent with the conventions of +`\.{\$\$...\$\$}', since `\.{\\abovedisplayskip}' inside a display affects the +space above that display. + +@<Finish math in text@>= +{@+tail_append(new_math(math_surround, before)); +cur_mlist=p;cur_style=text_style;mlist_penalties=(mode > 0);mlist_to_hlist(); +link(tail)=link(temp_head); +while (link(tail)!=null) tail=link(tail); +tail_append(new_math(math_surround, after)); +space_factor=1000;unsave(); +} + +@ \TeX\ gets to the following part of the program when the first `\.\$' ending +a display has been scanned. + +@<Check that another \.\$ follows@>= +{@+get_x_token(); +if (cur_cmd!=math_shift) + {@+print_err("Display math should end with $$"); +@.Display math...with \$\$@> + help2("The `$' that I just saw supposedly matches a previous `$$'.",@/ + "So I shall assume that you typed `$$' both times."); + back_error(); + } +} + +@ We have saved the worst for last: The fussiest part of math mode processing +occurs when a displayed formula is being centered and placed with an optional +equation number. + +@<Local variables for finishing...@>= +pointer @!b; /*box containing the equation*/ +scaled @!w; /*width of the equation*/ +scaled @!z; /*width of the line*/ +scaled @!e; /*width of equation number*/ +scaled @!q; /*width of equation number plus space to separate from equation*/ +scaled @!d; /*displacement of equation in the line*/ +scaled @!s; /*move the line right this much*/ +small_number @!g1, @!g2; /*glue parameter codes for before and after*/ +pointer @!r; /*kern node used to position the display*/ +pointer @!t; /*tail of adjustment list*/ + +@ At this time |p| points to the mlist for the formula; |a| is either +|null| or it points to a box containing the equation number; and we are in +vertical mode (or internal vertical mode). + +@<Finish displayed math@>= +cur_mlist=p;cur_style=display_style;mlist_penalties=false; +mlist_to_hlist();p=link(temp_head); link(temp_head)=null;@/ +{@+ pointer q; + q=new_disp_node(); + if (!danger) { display_formula(q)=p; display_eqno(q)=a; display_left(q)=l; } + /* adding parameter nodes */ + if (hang_indent!=0) + { add_par_node(dimen_type,hang_indent_code,hang_indent); + if (hang_after!=1) + add_par_node(int_type,hang_after_code,hang_after); + } + add_par_node(dimen_type,line_skip_limit_code,line_skip_limit); + add_par_node(glue_type,line_skip_code,line_skip); + add_par_node(glue_type,baseline_skip_code,baseline_skip); + display_params(q)=link(temp_head); link(temp_head)=null; + display_no_bs(q)= prev_depth <= ignore_depth; + tail_append(q); +} +/* this is from |resume_after_display| */ +if (cur_group!=math_shift_group) confusion("display"); +@:this can't happen display}{\quad display@> +unsave(); +mode=hmode;space_factor=1000;set_cur_lang;clang=cur_lang; +prev_graf=(norm_min(left_hyphen_min)*0100+norm_min(right_hyphen_min)) + *0200000+cur_lang; +@<Scan an optional space@>; + +@ @<Declare act...@>= +static void resume_after_display(void) +{@+if (cur_group!=math_shift_group) confusion("display"); +@:this can't happen display}{\quad display@> +unsave();prev_graf=prev_graf+3; +push_nest();mode=hmode;space_factor=1000;set_cur_lang;clang=cur_lang; +prev_graf=(norm_min(left_hyphen_min)*0100+norm_min(right_hyphen_min)) + *0200000+cur_lang; +@<Scan an optional space@>; +if (nest_ptr==1) build_page(); +} + +@ The user can force the equation number to go on a separate line +by causing its width to be zero. + +@<Squeeze the equation as much as possible...@>= +{@+if ((e!=0)&&((w-total_shrink[normal]+q <= z)||@| + (total_shrink[fil]!=0)||(total_shrink[fill]!=0)|| + (total_shrink[filll]!=0))) + {@+list_ptr(b)=null;flush_node_list(b); + b=hpack(p, z-q, 0, 0, exactly); + } +else{@+e=0; + if (w > z) + {@+list_ptr(b)=null;flush_node_list(b); + b=hpack(p, z, 0, 0, exactly); + } + } +w=width(b); +} + +@ We try first to center the display without regard to the existence of +the equation number. If that would make it too close (where ``too close'' +means that the space between display and equation number is less than the +width of the equation number), we either center it in the remaining space +or move it as far from the equation number as possible. The latter alternative +is taken only if the display begins with glue, since we assume that the +user put glue there to control the spacing precisely. + +@<Determine the displacement, |d|, of the left edge of the equation...@>= +d=half(z-w); +if ((e > 0)&&(d < 2*e)) /*too close*/ + {@+d=half(z-w-e); + if (p!=null) if (!is_char_node(p)) if (type(p)==glue_node) d=0; + } + +@ If the equation number is set on a line by itself, either before or +after the formula, we append an infinite penalty so that no page break will +separate the display from its number; and we use the same size and +displacement for all three potential lines of the display, even though +`\.{\\parshape}' may specify them differently. + +@<Append the glue or equation number preceding the display@>= +tail_append(new_penalty(pre_display_penalty));@/ +if ((d+s <= pre_display_size)||l) /*not enough clearance*/ + {@+g1=above_display_skip_code;g2=below_display_skip_code; + } +else{@+g1=above_display_short_skip_code; + g2=below_display_short_skip_code; + } +if (l&&(e==0)) /*it follows that |type(a)==hlist_node|*/ + {@+shift_amount(a)=s;append_to_vlist(a); + tail_append(new_penalty(inf_penalty)); + } +else tail_append(new_param_glue(g1)) + +@ @<Append the display and perhaps also the equation number@>= +if (e!=0) + {@+r=new_kern(z-w-e-d); + if (l) + {@+link(a)=r;link(r)=b;b=a;d=0; + } + else{@+link(b)=r;link(r)=a; + } + b=hpack(b, natural); + } +shift_amount(b)=s+d;append_to_vlist(b) + +@ @<Append the glue or equation number following the display@>= +if ((a!=null)&&(e==0)&&!l) + {@+tail_append(new_penalty(inf_penalty)); + shift_amount(a)=s+z-width(a); + append_to_vlist(a); + g2=0; + } +if (t!=adjust_head) /*migrating material comes after equation number*/ + {@+link(tail)=link(adjust_head);tail=t; + } +tail_append(new_penalty(post_display_penalty)); +if (g2 > 0) tail_append(new_param_glue(g2)) + +@ When \.{\\halign} appears in a display, the alignment routines operate +essentially as they do in vertical mode. Then the following program is +activated, with |p| and |q| pointing to the beginning and end of the +resulting list, and with |aux_save| holding the |prev_depth| value. + +@<Finish an alignment in a display@>= +{@+do_assignments(); +if (cur_cmd!=math_shift) @<Pontificate about improper alignment in display@>@; +else@<Check that another \.\$ follows@>; +pop_nest(); +tail_append(new_penalty(pre_display_penalty)); +tail_append(new_param_glue(above_display_skip_code)); +link(tail)=p; +if (p!=null) tail=q; +tail_append(new_penalty(post_display_penalty)); +tail_append(new_param_glue(below_display_skip_code)); +prev_depth=aux_save.sc;resume_after_display(); +} + +@ @<Pontificate...@>= +{@+print_err("Missing $$ inserted"); +@.Missing {\$\$} inserted@> +help2("Displays can use special alignments (like \\eqalignno)",@/ + "only if nothing but the alignment itself is between $$'s."); +back_error(); +} + +@* Mode-independent processing. +The long |main_control| procedure has now been fully specified, except for +certain activities that are independent of the current mode. These activities +do not change the current vlist or hlist or mlist; if they change anything, +it is the value of a parameter or the meaning of a control sequence. + +Assignments to values in |eqtb| can be global or local. Furthermore, a +control sequence can be defined to be `\.{\\long}', `\.{\\protected}', +or `\.{\\outer}', and it might or might not be expanded. The prefixes +`\.{\\global}', `\.{\\long}', `\.{\\protected}', +and `\.{\\outer}' can occur in any order. Therefore we assign binary numeric +codes, making it possible to accumulate the union of all specified prefixes +by adding the corresponding codes. (\PASCAL's |set| operations could also +have been used.) + +@<Put each...@>= +primitive("long", prefix, 1); +@!@:long\_}{\.{\\long} primitive@> +primitive("outer", prefix, 2); +@!@:outer\_}{\.{\\outer} primitive@> +primitive("global", prefix, 4); +@!@:global\_}{\.{\\global} primitive@> +primitive("def", def, 0); +@!@:def\_}{\.{\\def} primitive@> +primitive("gdef", def, 1); +@!@:gdef\_}{\.{\\gdef} primitive@> +primitive("edef", def, 2); +@!@:edef\_}{\.{\\edef} primitive@> +primitive("xdef", def, 3); +@!@:xdef\_}{\.{\\xdef} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case prefix: if (chr_code==1) print_esc("long"); + else if (chr_code==2) print_esc("outer") + @/@<Cases of |prefix| for |print_cmd_chr|@>;@/ + else print_esc("global");@+break; +case def: if (chr_code==0) print_esc("def"); + else if (chr_code==1) print_esc("gdef"); + else if (chr_code==2) print_esc("edef"); + else print_esc("xdef");@+break; + +@ Every prefix, and every command code that might or might not be prefixed, +calls the action procedure |prefixed_command|. This routine accumulates +a sequence of prefixes until coming to a non-prefix, then it carries out +the command. + +@<Cases of |main_control| that don't...@>= +any_mode(toks_register): +any_mode(assign_toks): +any_mode(assign_int): +any_mode(assign_dimen): +any_mode(assign_glue): +any_mode(assign_mu_glue): +any_mode(assign_font_dimen): +any_mode(assign_font_int): +any_mode(set_aux): +any_mode(set_prev_graf): +any_mode(set_page_dimen): +any_mode(set_page_int): +any_mode(set_box_dimen): +any_mode(set_shape): +any_mode(def_code): +any_mode(def_family): +any_mode(set_font): +any_mode(def_font): +any_mode(internal_register): +any_mode(advance): +any_mode(multiply): +any_mode(divide): +any_mode(prefix): +any_mode(let): +any_mode(shorthand_def): +any_mode(read_to_cs): +any_mode(def): +any_mode(set_box): +any_mode(hyph_data): +any_mode(set_interaction): prefixed_command();@+break; + +@ If the user says, e.g., `\.{\\global\\global}', the redundancy is +silently accepted. + +@<Declare act...@>= +@t\4@>@<Declare subprocedures for |prefixed_command|@>@t@>@;@/ +static void prefixed_command(void) +{@+ +small_number a; /*accumulated prefix codes so far*/ +internal_font_number @!f; /*identifies a font*/ +int @!j; /*index into a \.{\\parshape} specification*/ +font_index @!k; /*index into |font_info|*/ +pointer @!p, @!q; /*for temporary short-term use*/ +int @!n; /*ditto*/ +bool @!e; /*should a definition be expanded? or was \.{\\let} not done?*/ +a=0; +while (cur_cmd==prefix) + {@+if (!odd(a/cur_chr)) a=a+cur_chr; + @<Get the next non-blank non-relax...@>; + if (cur_cmd <= max_non_prefixed_command) + @<Discard erroneous prefixes and |return|@>; + if (tracing_commands > 2) if (eTeX_ex) show_cur_cmd_chr(); + } +@<Discard the prefixes \.{\\long} and \.{\\outer} if they are irrelevant@>; +@<Adjust \(f)for the setting of \.{\\globaldefs}@>; +switch (cur_cmd) { +@t\4@>@<Assignments@>@; +default:confusion("prefix"); +@:this can't happen prefix}{\quad prefix@> +} +done: @<Insert a token saved by \.{\\afterassignment}, if any@>; +} + +@ @<Discard erroneous...@>= +{@+print_err("You can't use a prefix with `"); +@.You can't use a prefix with x@> +print_cmd_chr(cur_cmd, cur_chr);print_char('\''); +help1("I'll pretend you didn't say \\long or \\outer or \\global."); +if (eTeX_ex) help_line[0]=@| + "I'll pretend you didn't say \\long or \\outer or \\global or \\protected."; +back_error();return; +} + +@ @<Discard the prefixes...@>= +if (a >= 8) + {@+j=protected_token;a=a-8; + } +else j=0; +if ((cur_cmd!=def)&&((a%4!=0)||(j!=0))) + {@+print_err("You can't use `");print_esc("long");print("' or `"); + print_esc("outer"); + help1("I'll pretend you didn't say \\long or \\outer here."); + if (eTeX_ex) + {@+help_line[0]=@| + "I'll pretend you didn't say \\long or \\outer or \\protected here."; + print("' or `");print_esc("protected"); + } + print("' with `"); +@.You can't use \\long...@> + print_cmd_chr(cur_cmd, cur_chr);print_char('\''); + error(); + } + +@ The previous routine does not have to adjust |a| so that |a%4==0|, +since the following routines test for the \.{\\global} prefix as follows. + +@d global (a >= 4) +@d define(A, B, C) if (global) geq_define(A, B, C);@+else eq_define(A, B, C) +@d word_define(A, B) if (global) geq_word_define(A, B);@+else eq_word_define(A, B) + +@<Adjust \(f)for the setting of \.{\\globaldefs}@>= +if (global_defs!=0) + if (global_defs < 0) + {@+if (global) a=a-4; + } + else{@+if (!global) a=a+4; + } + +@ When a control sequence is to be defined, by \.{\\def} or \.{\\let} or +something similar, the |get_r_token| routine will substitute a special +control sequence for a token that is not redefinable. + +@<Declare subprocedures for |prefixed_command|@>= +static void get_r_token(void) +{@+ +restart: @/do@+{get_token(); +}@+ while (!(cur_tok!=space_token)); +if ((cur_cs==0)||(cur_cs > frozen_control_sequence)) + {@+print_err("Missing control sequence inserted"); +@.Missing control...@> + help5("Please don't say `\\def cs{...}', say `\\def\\cs{...}'.",@/ + "I've inserted an inaccessible control sequence so that your",@/ + "definition will be completed without mixing me up too badly.",@/ + "You can recover graciously from this error, if you're",@/ + "careful; see exercise 27.2 in The TeXbook."); +@:TeXbook}{\sl The \TeX book@> + if (cur_cs==0) back_input(); + cur_tok=cs_token_flag+frozen_protection;ins_error();goto restart; + } +} + +@ @<Initialize table entries...@>= +text(frozen_protection)=s_no("inaccessible"); + +@ Here's an example of the way many of the following routines operate. +(Unfortunately, they aren't all as simple as this.) + +@<Assignments@>= +case set_font: define(cur_font_loc, data, cur_chr);@+break; + +@ When a |def| command has been scanned, +|cur_chr| is odd if the definition is supposed to be global, and +|cur_chr >= 2| if the definition is supposed to be expanded. + +@<Assignments@>= +case def: {@+if (odd(cur_chr)&&!global&&(global_defs >= 0)) a=a+4; + e=(cur_chr >= 2);get_r_token();p=cur_cs; + q=scan_toks(true, e); + if (j!=0) + {@+q=get_avail();info(q)=j;link(q)=link(def_ref); + link(def_ref)=q; + } + define(p, call+(a%4), def_ref); + } @+break; + +@ Both \.{\\let} and \.{\\futurelet} share the command code |let|. + +@<Put each...@>= +primitive("let", let, normal);@/ +@!@:let\_}{\.{\\let} primitive@> +primitive("futurelet", let, normal+1);@/ +@!@:future\_let\_}{\.{\\futurelet} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case let: if (chr_code!=normal) print_esc("futurelet");@+else print_esc("let");@+break; + +@ @<Assignments@>= +case let: {@+n=cur_chr; + get_r_token();p=cur_cs; + if (n==normal) + {@+@/do@+{get_token(); + }@+ while (!(cur_cmd!=spacer)); + if (cur_tok==other_token+'=') + {@+get_token(); + if (cur_cmd==spacer) get_token(); + } + } + else{@+get_token();q=cur_tok;get_token();back_input(); + cur_tok=q;back_input(); /*look ahead, then back up*/ + } /*note that |back_input| doesn't affect |cur_cmd|, |cur_chr|*/ + if (cur_cmd >= call) add_token_ref(cur_chr); + else if ((cur_cmd==internal_register)||(cur_cmd==toks_register)) + if ((cur_chr < mem_bot)||(cur_chr > lo_mem_stat_max)) + add_sa_ref(cur_chr); + define(p, cur_cmd, cur_chr); + } @+break; + +@ A \.{\\chardef} creates a control sequence whose |cmd| is |char_given|; +a \.{\\mathchardef} creates a control sequence whose |cmd| is |math_given|; +and the corresponding |chr| is the character code or math code. A \.{\\countdef} +or \.{\\dimendef} or \.{\\skipdef} or \.{\\muskipdef} creates a control +sequence whose |cmd| is |assign_int| or \dots\ or |assign_mu_glue|, and the +corresponding |chr| is the |eqtb| location of the internal register in question. + +@d char_def_code 0 /*|shorthand_def| for \.{\\chardef}*/ +@d math_char_def_code 1 /*|shorthand_def| for \.{\\mathchardef}*/ +@d count_def_code 2 /*|shorthand_def| for \.{\\countdef}*/ +@d dimen_def_code 3 /*|shorthand_def| for \.{\\dimendef}*/ +@d skip_def_code 4 /*|shorthand_def| for \.{\\skipdef}*/ +@d mu_skip_def_code 5 /*|shorthand_def| for \.{\\muskipdef}*/ +@d toks_def_code 6 /*|shorthand_def| for \.{\\toksdef}*/ + +@<Put each...@>= +primitive("chardef", shorthand_def, char_def_code);@/ +@!@:char\_def\_}{\.{\\chardef} primitive@> +primitive("mathchardef", shorthand_def, math_char_def_code);@/ +@!@:math\_char\_def\_}{\.{\\mathchardef} primitive@> +primitive("countdef", shorthand_def, count_def_code);@/ +@!@:count\_def\_}{\.{\\countdef} primitive@> +primitive("dimendef", shorthand_def, dimen_def_code);@/ +@!@:dimen\_def\_}{\.{\\dimendef} primitive@> +primitive("skipdef", shorthand_def, skip_def_code);@/ +@!@:skip\_def\_}{\.{\\skipdef} primitive@> +primitive("muskipdef", shorthand_def, mu_skip_def_code);@/ +@!@:mu\_skip\_def\_}{\.{\\muskipdef} primitive@> +primitive("toksdef", shorthand_def, toks_def_code);@/ +@!@:toks\_def\_}{\.{\\toksdef} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case shorthand_def: switch (chr_code) { + case char_def_code: print_esc("chardef");@+break; + case math_char_def_code: print_esc("mathchardef");@+break; + case count_def_code: print_esc("countdef");@+break; + case dimen_def_code: print_esc("dimendef");@+break; + case skip_def_code: print_esc("skipdef");@+break; + case mu_skip_def_code: print_esc("muskipdef");@+break; + default:print_esc("toksdef"); + } @+break; +case char_given: {@+print_esc("char");print_hex(chr_code); + } @+break; +case math_given: {@+print_esc("mathchar");print_hex(chr_code); + } @+break; + +@ We temporarily define |p| to be |relax|, so that an occurrence of |p| +while scanning the definition will simply stop the scanning instead of +producing an ``undefined control sequence'' error or expanding the +previous meaning. This allows, for instance, `\.{\\chardef\\foo=123\\foo}'. + +@<Assignments@>= +case shorthand_def: {@+n=cur_chr;get_r_token();p=cur_cs;define(p, relax, 256); + scan_optional_equals(); + switch (n) { + case char_def_code: {@+scan_char_num();define(p, char_given, cur_val); + } @+break; + case math_char_def_code: {@+scan_fifteen_bit_int();define(p, math_given, cur_val); + } @+break; + default:{@+scan_register_num(); + if (cur_val > 255) + {@+j=n-count_def_code; /*|int_val dotdot box_val|*/ + if (j > mu_val) j=tok_val; /*|int_val dotdot mu_val| or |tok_val|*/ + find_sa_element(j, cur_val, true);add_sa_ref(cur_ptr); + if (j==tok_val) j=toks_register;@+else j=internal_register; + define(p, j, cur_ptr); + } + else + switch (n) { + case count_def_code: define(p, assign_int, count_base+cur_val);@+break; + case dimen_def_code: define(p, assign_dimen, scaled_base+cur_val);@+break; + case skip_def_code: define(p, assign_glue, skip_base+cur_val);@+break; + case mu_skip_def_code: define(p, assign_mu_glue, mu_skip_base+cur_val);@+break; + case toks_def_code: define(p, assign_toks, toks_base+cur_val); + } /*there are no other cases*/ + } + } + } @+break; + +@ @<Assignments@>= +case read_to_cs: {@+j=cur_chr;scan_int();n=cur_val; + if (!scan_keyword("to")) +@.to@> + {@+print_err("Missing `to' inserted"); +@.Missing `to'...@> + help2("You should have said `\\read<number> to \\cs'.",@/ + "I'm going to look for the \\cs now.");error(); + } + get_r_token(); + p=cur_cs;read_toks(n, p, j);define(p, call, cur_val); + } @+break; + +@ The token-list parameters, \.{\\output} and \.{\\everypar}, etc., receive +their values in the following way. (For safety's sake, we place an +enclosing pair of braces around an \.{\\output} list.) + +@<Assignments@>= +case toks_register: case assign_toks: {@+q=cur_cs; + e=false; /*just in case, will be set |true| for sparse array elements*/ + if (cur_cmd==toks_register) + if (cur_chr==mem_bot) + {@+scan_register_num(); + if (cur_val > 255) + {@+find_sa_element(tok_val, cur_val, true); + cur_chr=cur_ptr;e=true; + } + else cur_chr=toks_base+cur_val; + } + else e=true; + p=cur_chr; /*|p==every_par_loc| or |output_routine_loc| or \dots*/ + scan_optional_equals(); + @<Get the next non-blank non-relax non-call token@>; + if (cur_cmd!=left_brace) @<If the right-hand side is a token parameter or token +register, finish the assignment and |goto done|@>; + back_input();cur_cs=q;q=scan_toks(false, false); + if (link(def_ref)==null) /*empty list: revert to the default*/ + {@+sa_define(p, null, p, undefined_cs, null);free_avail(def_ref); + } + else{@+if ((p==output_routine_loc)&&!e) /*enclose in curlies*/ + {@+link(q)=get_avail();q=link(q); + info(q)=right_brace_token+'}'; + q=get_avail();info(q)=left_brace_token+'{'; + link(q)=link(def_ref);link(def_ref)=q; + } + sa_define(p, def_ref, p, call, def_ref); + } + } @+break; + +@ @<If the right-hand side is a token parameter...@>= +if ((cur_cmd==toks_register)||(cur_cmd==assign_toks)) + {@+if (cur_cmd==toks_register) + if (cur_chr==mem_bot) + {@+scan_register_num(); + if (cur_val < 256) q=equiv(toks_base+cur_val); + else{@+find_sa_element(tok_val, cur_val, false); + if (cur_ptr==null) q=null; + else q=sa_ptr(cur_ptr); + } + } + else q=sa_ptr(cur_chr); + else q=equiv(cur_chr); + if (q==null) sa_define(p, null, p, undefined_cs, null); + else{@+add_token_ref(q);sa_define(p, q, p, call, q); + } + goto done; + } + +@ Similar routines are used to assign values to the numeric parameters. + +@<Assignments@>= +case assign_int: {@+p=cur_chr;scan_optional_equals();scan_int(); + word_define(p, cur_val); + } @+break; +case assign_dimen: {@+p=cur_chr;scan_optional_equals(); + scan_normal_dimen;word_define(p, cur_val); + } @+break; +case assign_glue: case assign_mu_glue: {@+p=cur_chr;n=cur_cmd;scan_optional_equals(); + if (n==assign_mu_glue) scan_glue(mu_val);@+else scan_glue(glue_val); + trap_zero_glue(); + define(p, glue_ref, cur_val); + } @+break; + +@ When a glue register or parameter becomes zero, it will always point to +|zero_glue| because of the following procedure. (Exception: The tabskip +glue isn't trapped while preambles are being scanned.) + +@<Declare subprocedures for |prefixed_command|@>= +static void trap_zero_glue(void) +{@+if ((width(cur_val)==0)&&(stretch(cur_val)==0)&&(shrink(cur_val)==0)) + {@+add_glue_ref(zero_glue); + delete_glue_ref(cur_val);cur_val=zero_glue; + } +} + +@ The various character code tables are changed by the |def_code| commands, +and the font families are declared by |def_family|. + +@<Put each...@>= +primitive("catcode", def_code, cat_code_base); +@!@:cat\_code\_}{\.{\\catcode} primitive@> +primitive("mathcode", def_code, math_code_base); +@!@:math\_code\_}{\.{\\mathcode} primitive@> +primitive("lccode", def_code, lc_code_base); +@!@:lc\_code\_}{\.{\\lccode} primitive@> +primitive("uccode", def_code, uc_code_base); +@!@:uc\_code\_}{\.{\\uccode} primitive@> +primitive("sfcode", def_code, sf_code_base); +@!@:sf\_code\_}{\.{\\sfcode} primitive@> +primitive("delcode", def_code, del_code_base); +@!@:del\_code\_}{\.{\\delcode} primitive@> +primitive("textfont", def_family, math_font_base); +@!@:text\_font\_}{\.{\\textfont} primitive@> +primitive("scriptfont", def_family, math_font_base+script_size); +@!@:script\_font\_}{\.{\\scriptfont} primitive@> +primitive("scriptscriptfont", def_family, math_font_base+script_script_size); +@!@:script\_script\_font\_}{\.{\\scriptscriptfont} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case def_code: if (chr_code==cat_code_base) print_esc("catcode"); + else if (chr_code==math_code_base) print_esc("mathcode"); + else if (chr_code==lc_code_base) print_esc("lccode"); + else if (chr_code==uc_code_base) print_esc("uccode"); + else if (chr_code==sf_code_base) print_esc("sfcode"); + else print_esc("delcode");@+break; +case def_family: print_size(chr_code-math_font_base);@+break; + +@ The different types of code values have different legal ranges; the +following program is careful to check each case properly. + +@<Assignments@>= +case def_code: {@+@<Let |n| be the largest legal code value, based on |cur_chr|@>; + p=cur_chr;scan_char_num();p=p+cur_val;scan_optional_equals(); + scan_int(); + if (((cur_val < 0)&&(p < del_code_base))||(cur_val > n)) + {@+print_err("Invalid code (");print_int(cur_val); +@.Invalid code@> + if (p < del_code_base) print("), should be in the range 0.."); + else print("), should be at most "); + print_int(n); + help1("I'm going to use 0 instead of that illegal code value.");@/ + error();cur_val=0; + } + if (p < math_code_base) define(p, data, cur_val); + else if (p < del_code_base) define(p, data, hi(cur_val)); + else word_define(p, cur_val); + } @+break; + +@ @<Let |n| be the largest...@>= +if (cur_chr==cat_code_base) n=max_char_code; +else if (cur_chr==math_code_base) n=0100000; +else if (cur_chr==sf_code_base) n=077777; +else if (cur_chr==del_code_base) n=077777777; +else n=255 + +@ @<Assignments@>= +case def_family: {@+p=cur_chr;scan_four_bit_int();p=p+cur_val; + scan_optional_equals();scan_font_ident();define(p, data, cur_val); + } @+break; + +@ Next we consider changes to \TeX's numeric registers. + +@<Assignments@>= +case internal_register: case advance: case multiply: case divide: do_register_command(a);@+break; + +@ We use the fact that |internal_register < advance < multiply < divide|. + +@<Declare subprocedures for |prefixed_command|@>= +static void do_register_command(small_number @!a) +{@+ +pointer l, @!q, @!r, @!s; /*for list manipulation*/ +int @!p; /*type of register involved*/ +bool @!e; /*does |l| refer to a sparse array element?*/ +int @!w; /*integer or dimen value of |l|*/ +q=cur_cmd; +e=false; /*just in case, will be set |true| for sparse array elements*/ +@<Compute the register location |l| and its type |p|; but |return| if invalid@>; +if (q==internal_register) scan_optional_equals(); +else if (scan_keyword("by")) do_nothing; /*optional `\.{by}'*/ +@.by@> +arith_error=false; +if (q < multiply) @<Compute result of |register| or |advance|, put it in |cur_val|@>@; +else@<Compute result of |multiply| or |divide|, put it in |cur_val|@>; +if (arith_error) + {@+print_err("Arithmetic overflow"); +@.Arithmetic overflow@> + help2("I can't carry out that multiplication or division,",@/ + "since the result is out of range."); + if (p >= glue_val) delete_glue_ref(cur_val); + error();return; + } +if (p < glue_val) sa_word_define(l, cur_val); +else{@+trap_zero_glue();sa_define(l, cur_val, l, glue_ref, cur_val); + } +} + +@ Here we use the fact that the consecutive codes |int_val dotdot mu_val| and +|assign_int dotdot assign_mu_glue| correspond to each other nicely. + +@<Compute the register location |l| and its type |p|...@>= +{@+if (q!=internal_register) + {@+get_x_token(); + if ((cur_cmd >= assign_int)&&(cur_cmd <= assign_mu_glue)) + {@+l=cur_chr;p=cur_cmd-assign_int;goto found; + } + if (cur_cmd!=internal_register) + {@+print_err("You can't use `");print_cmd_chr(cur_cmd, cur_chr); +@.You can't use x after ...@> + print("' after ");print_cmd_chr(q, 0); + help1("I'm forgetting what you said and not changing anything."); + error();return; + } + } +if ((cur_chr < mem_bot)||(cur_chr > lo_mem_stat_max)) + {@+l=cur_chr;p=sa_type(l);e=true; + } +else{@+p=cur_chr-mem_bot;scan_register_num(); + if (cur_val > 255) + {@+find_sa_element(p, cur_val, true);l=cur_ptr;e=true; + } + else +switch (p) { +case int_val: l=cur_val+count_base;@+break; +case dimen_val: l=cur_val+scaled_base;@+break; +case glue_val: l=cur_val+skip_base;@+break; +case mu_val: l=cur_val+mu_skip_base; +} /*there are no other cases*/ + } +} +found: if (p < glue_val) @+if (e) w=sa_int(l);@+else w=eqtb[l].i; +else if (e) s=sa_ptr(l);@+else s=equiv(l) + +@ @<Compute result of |register| or |advance|...@>= +if (p < glue_val) + {@+if (p==int_val) scan_int();@+else scan_normal_dimen; + if (q==advance) + { cur_val=cur_val+w; + if (!e && l>=dimen_base) + { cur_hfactor+=hfactor_eqtb[l].sc; + cur_vfactor+=vfactor_eqtb[l].sc; + } + } + } +else{@+scan_glue(p); + if (q==advance) @<Compute the sum of two glue specs@>; + } + +@ @<Compute the sum of two glue specs@>= +{@+q=new_spec(cur_val);r=s; +delete_glue_ref(cur_val); +width(q)=width(q)+width(r); +if (stretch(q)==0) stretch_order(q)=normal; +if (stretch_order(q)==stretch_order(r)) stretch(q)=stretch(q)+stretch(r); +else if ((stretch_order(q) < stretch_order(r))&&(stretch(r)!=0)) + {@+stretch(q)=stretch(r);stretch_order(q)=stretch_order(r); + } +if (shrink(q)==0) shrink_order(q)=normal; +if (shrink_order(q)==shrink_order(r)) shrink(q)=shrink(q)+shrink(r); +else if ((shrink_order(q) < shrink_order(r))&&(shrink(r)!=0)) + {@+shrink(q)=shrink(r);shrink_order(q)=shrink_order(r); + } +cur_val=q; +} + +@ @<Compute result of |multiply| or |divide|...@>= +{@+scan_int(); +if (p < glue_val) + if (q==multiply) + if (p==int_val) cur_val=mult_integers(w, cur_val); + else cur_val=nx_plus_y(w, cur_val, 0); + else cur_val=x_over_n(w, cur_val); +else{@+r=new_spec(s); + if (q==multiply) + {@+width(r)=nx_plus_y(width(s), cur_val, 0); + stretch(r)=nx_plus_y(stretch(s), cur_val, 0); + shrink(r)=nx_plus_y(shrink(s), cur_val, 0); + } + else{@+width(r)=x_over_n(width(s), cur_val); + stretch(r)=x_over_n(stretch(s), cur_val); + shrink(r)=x_over_n(shrink(s), cur_val); + } + cur_val=r; + } +} + +@ The processing of boxes is somewhat different, because we may need +to scan and create an entire box before we actually change the value of the old +one. + +@<Assignments@>= +case set_box: {@+scan_register_num(); + if (global) n=global_box_flag+cur_val;@+else n=box_flag+cur_val; + scan_optional_equals(); + if (set_box_allowed) scan_box(n); + else{@+print_err("Improper ");print_esc("setbox"); +@.Improper \\setbox@> + help2("Sorry, \\setbox is not allowed after \\halign in a display,",@/ + "or between \\accent and an accented character.");error(); + } + } @+break; + +@ The |space_factor| or |prev_depth| settings are changed when a |set_aux| +command is sensed. Similarly, |prev_graf| is changed in the presence of +|set_prev_graf|, and |dead_cycles| or |insert_penalties| in the presence of +|set_page_int|. These definitions are always global. + +When some dimension of a box register is changed, the change isn't exactly +global; but \TeX\ does not look at the \.{\\global} switch. + +@<Assignments@>= +case set_aux: alter_aux();@+break; +case set_prev_graf: alter_prev_graf();@+break; +case set_page_dimen: alter_page_so_far();@+break; +case set_page_int: alter_integer();@+break; +case set_box_dimen: alter_box_dimen();@+break; + +@ @<Declare subprocedures for |prefixed_command|@>= +static void alter_aux(void) +{@+halfword c; /*|hmode| or |vmode|*/ +if (cur_chr!=abs(mode)) report_illegal_case(); +else{@+c=cur_chr;scan_optional_equals(); + if (c==vmode) + {@+scan_normal_dimen;prev_depth=cur_val; + } + else{@+scan_int(); + if ((cur_val <= 0)||(cur_val > 32767)) + {@+print_err("Bad space factor"); +@.Bad space factor@> + help1("I allow only values in the range 1..32767 here."); + int_error(cur_val); + } + else space_factor=cur_val; + } + } +} + +@ @<Declare subprocedures for |prefixed_command|@>= +static void alter_prev_graf(void) +{@+int p; /*index into |nest|*/ +nest[nest_ptr]=cur_list;p=nest_ptr; +while (abs(nest[p].mode_field)!=vmode) decr(p); +scan_optional_equals();scan_int(); +if (cur_val < 0) + {@+print_err("Bad ");print_esc("prevgraf"); +@.Bad \\prevgraf@> + help1("I allow only nonnegative values here."); + int_error(cur_val); + } +else{@+nest[p].pg_field=cur_val;cur_list=nest[nest_ptr]; + } +} + +@ @<Declare subprocedures for |prefixed_command|@>= +static void alter_page_so_far(void) +{@+int c; /*index into |page_so_far|*/ +c=cur_chr;scan_optional_equals();scan_normal_dimen; +page_so_far[c]=cur_val; +} + +@ @<Declare subprocedures for |prefixed_command|@>= +static void alter_integer(void) +{@+small_number c; + /*0 for \.{\\deadcycles}, 1 for \.{\\insertpenalties}, etc.*/ +c=cur_chr;scan_optional_equals();scan_int(); +if (c==0) dead_cycles=cur_val +@/@<Cases for |alter_integer|@>@;@/ +else insert_penalties=cur_val; +} + +@ @<Declare subprocedures for |prefixed_command|@>= +static void alter_box_dimen(void) +{@+small_number c; /*|width_offset| or |height_offset| or |depth_offset|*/ +pointer @!b; /*box register*/ +c=cur_chr;scan_register_num();fetch_box(b);scan_optional_equals(); +scan_normal_dimen; +if (b!=null) mem[b+c].sc=cur_val; +} + +@ Paragraph shapes are set up in the obvious way. + +@<Assignments@>= +case set_shape: {@+q=cur_chr;scan_optional_equals();scan_int();n=cur_val; + if (n <= 0) p=null; + else if (q > par_shape_loc) + {@+n=(cur_val/2)+1;p=get_node(2*n+1);info(p)=n; + n=cur_val;mem[p+1].i=n; /*number of penalties*/ + for (j=p+2; j<=p+n+1; j++) + {@+scan_int();mem[j].i=cur_val; /*penalty values*/ + } + if (!odd(n)) mem[p+n+2].i=0; /*unused*/ + } + else{@+ + scaled fh=0, fv=0; + p=get_node(2*n+1);info(p)=n; + for (j=1; j<=n; j++) + {@+scan_normal_dimen; + mem[p+2*j-1].sc=cur_val; /*indentation*/ + scan_normal_dimen; + if (j==1) {fh=cur_hfactor; fv=cur_vfactor;} + mem[p+2*j].sc=cur_val; /*width*/ + } + cur_hfactor=fh; cur_vfactor=fv; + } + define(q, shape_ref, p); + } @+break; + +@ Here's something that isn't quite so obvious. It guarantees that +|info(par_shape_ptr)| can hold any positive~|n| for which |get_node(2*n+1)| +doesn't overflow the memory capacity. + +@<Check the ``constant''...@>= +if (2*max_halfword < mem_top-mem_min) bad=41; + +@ New hyphenation data is loaded by the |hyph_data| command. + +@<Put each...@>= +primitive("hyphenation", hyph_data, 0); +@!@:hyphenation\_}{\.{\\hyphenation} primitive@> +primitive("patterns", hyph_data, 1); +@!@:patterns\_}{\.{\\patterns} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case hyph_data: if (chr_code==1) print_esc("patterns"); + else print_esc("hyphenation");@+break; + +@ @<Assignments@>= +case hyph_data: if (cur_chr==1) + { +#ifdef @!INIT +new_patterns();goto done;@; +#endif + print_err("Patterns can be loaded only by INITEX"); +@.Patterns can be...@> + help0;error(); + @/do@+{get_token();}@+ while (!(cur_cmd==right_brace)); /*flush the patterns*/ + return; + } + else{@+new_hyph_exceptions();goto done; + } @+break; + +@ All of \TeX's parameters are kept in |eqtb| except the font information, +the interaction mode, and the hyphenation tables; these are strictly global. + +@<Assignments@>= +case assign_font_dimen: {@+find_font_dimen(true);k=cur_val; + scan_optional_equals();scan_normal_dimen;font_info[k].sc=cur_val; + } @+break; +case assign_font_int: {@+n=cur_chr;scan_font_ident();f=cur_val; + scan_optional_equals();scan_int(); + if (n==0) hyphen_char[f]=cur_val;@+else skew_char[f]=cur_val; + } @+break; + +@ @<Put each...@>= +primitive("hyphenchar", assign_font_int, 0); +@!@:hyphen\_char\_}{\.{\\hyphenchar} primitive@> +primitive("skewchar", assign_font_int, 1); +@!@:skew\_char\_}{\.{\\skewchar} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case assign_font_int: if (chr_code==0) print_esc("hyphenchar"); + else print_esc("skewchar");@+break; + +@ Here is where the information for a new font gets loaded. + +@<Assignments@>= +case def_font: new_font(a);@+break; + +@ @<Declare subprocedures for |prefixed_command|@>= +static void new_font(small_number @!a) +{@+ +pointer u; /*user's font identifier*/ +scaled @!s; /*stated ``at'' size, or negative of scaled magnification*/ +int @!f; /*runs through existing fonts*/ +str_number @!t; /*name for the frozen font identifier*/ +int @!old_setting; /*holds |selector| setting*/ +str_number @!flushable_string; /*string not yet referenced*/ +if (job_name==0) open_log_file(); + /*avoid confusing \.{texput} with the font name*/ +@.texput@> +get_r_token();u=cur_cs; +if (u >= hash_base) t=text(u); +else if (u >= single_base) + if (u==null_cs) t=s_no("FONT");@+else t=u-single_base; +else{@+old_setting=selector;selector=new_string; + print("FONT");printn(u-active_base);selector=old_setting; +@.FONTx@> + str_room(1);t=make_string(); + } +define(u, set_font, null_font);scan_optional_equals();scan_file_name(); +@<Scan the font size specification@>; +@<If this font has already been loaded, set |f| to the internal font number and |goto +common_ending|@>; +f=read_font_info(u, cur_name, cur_area, s); +common_ending: define(u, set_font, f);eqtb[font_id_base+f]=eqtb[u];font_id_text(f)=t; +} + +@ @<Scan the font size specification@>= +name_in_progress=true; /*this keeps |cur_name| from being changed*/ +if (scan_keyword("at")) @<Put the \(p)(positive) `at' size into |s|@>@; +@.at@> +else if (scan_keyword("scaled")) +@.scaled@> + {@+scan_int();s=-cur_val; + if ((cur_val <= 0)||(cur_val > 32768)) + {@+print_err("Illegal magnification has been changed to 1000");@/ +@.Illegal magnification...@> + help1("The magnification ratio must be between 1 and 32768."); + int_error(cur_val);s=-1000; + } + } +else s=-1000; +name_in_progress=false + +@ @<Put the \(p)(positive) `at' size into |s|@>= +{@+scan_normal_dimen;s=cur_val; +if ((s <= 0)||(s >= 01000000000)) + {@+print_err("Improper `at' size ("); + print_scaled(s);print("pt), replaced by 10pt"); +@.Improper `at' size...@> + help2("I can only handle fonts at positive sizes that are",@/ + "less than 2048pt, so I've changed what you said to 10pt."); + error();s=10*unity; + } +} + +@ When the user gives a new identifier to a font that was previously loaded, +the new name becomes the font identifier of record. Font names `\.{xyz}' and +`\.{XYZ}' are considered to be different. + +@<If this font has already been loaded...@>= +flushable_string=str_ptr-1; +for (f=font_base+1; f<=font_ptr; f++) + if (strn_eq_str(font_name[f], cur_name)&&str_eq_str(font_area[f], cur_area)) + {@+if (cur_name==flushable_string) + {@+flush_string;cur_name=font_name[f]; + } + if (s > 0) + {@+if (s==font_size[f]) goto common_ending; + } + else if (font_size[f]==xn_over_d(font_dsize[f],-s, 1000)) + goto common_ending; + } + +@ @<Cases of |print_cmd_chr|...@>= +case set_font: {@+print("select font ");slow_print(font_name[chr_code]); + if (font_size[chr_code]!=font_dsize[chr_code]) + {@+print(" at ");print_scaled(font_size[chr_code]); + print("pt"); + } + } @+break; + +@ @<Put each...@>= +primitive("batchmode", set_interaction, batch_mode); +@!@:batch\_mode\_}{\.{\\batchmode} primitive@> +primitive("nonstopmode", set_interaction, nonstop_mode); +@!@:nonstop\_mode\_}{\.{\\nonstopmode} primitive@> +primitive("scrollmode", set_interaction, scroll_mode); +@!@:scroll\_mode\_}{\.{\\scrollmode} primitive@> +primitive("errorstopmode", set_interaction, error_stop_mode); +@!@:error\_stop\_mode\_}{\.{\\errorstopmode} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case set_interaction: switch (chr_code) { + case batch_mode: print_esc("batchmode");@+break; + case nonstop_mode: print_esc("nonstopmode");@+break; + case scroll_mode: print_esc("scrollmode");@+break; + default:print_esc("errorstopmode"); + } @+break; + +@ @<Assignments@>= +case set_interaction: new_interaction();@+break; + +@ @<Declare subprocedures for |prefixed_command|@>= +static void new_interaction(void) +{@+print_ln(); +interaction=cur_chr; +@<Initialize the print |selector| based on |interaction|@>; +if (log_opened) selector=selector+2; +} + +@ The \.{\\afterassignment} command puts a token into the global +variable |after_token|. This global variable is examined just after +every assignment has been performed. + +@<Glob...@>= +static halfword @!after_token; /*zero, or a saved token*/ + +@ @<Set init...@>= +after_token=0; + +@ @<Cases of |main_control| that don't...@>= +any_mode(after_assignment): {@+get_token();after_token=cur_tok; + } @+break; + +@ @<Insert a token saved by \.{\\afterassignment}, if any@>= +if (after_token!=0) + {@+cur_tok=after_token;back_input();after_token=0; + } + +@ Here is a procedure that might be called `Get the next non-blank non-relax +non-call non-assignment token'. + +@<Declare act...@>= +static void do_assignments(void) +{@+ +loop{@+@<Get the next non-blank non-relax...@>; + if (cur_cmd <= max_non_prefixed_command) return; + set_box_allowed=false;prefixed_command();set_box_allowed=true; + } +} + +@ @<Cases of |main_control| that don't...@>= +any_mode(after_group): {@+get_token();save_for_after(cur_tok); + } @+break; + +@ Files for \.{\\read} are opened and closed by the |in_stream| command. + +@<Put each...@>= +primitive("openin", in_stream, 1); +@!@:open\_in\_}{\.{\\openin} primitive@> +primitive("closein", in_stream, 0); +@!@:close\_in\_}{\.{\\closein} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case in_stream: if (chr_code==0) print_esc("closein"); + else print_esc("openin");@+break; + +@ @<Cases of |main_control| that don't...@>= +any_mode(in_stream): open_or_close_in();@+break; + +@ @<Declare act...@>= +static void open_or_close_in(void) +{@+int c; /*1 for \.{\\openin}, 0 for \.{\\closein}*/ +int @!n; /*stream number*/ +c=cur_chr;scan_four_bit_int();n=cur_val; +if (read_open[n]!=closed) + {@+a_close(&read_file[n]);read_open[n]=closed; + } +if (c!=0) + {@+scan_optional_equals();scan_file_name(); + if (cur_ext[0]==0) cur_ext=".tex"; + pack_cur_name; + if (a_open_in(&read_file[n])) read_open[n]=just_open; + } +} + +@ The user can issue messages to the terminal, regardless of the +current mode. + +@<Cases of |main_control| that don't...@>= +any_mode(message): issue_message();@+break; + +@ @<Put each...@>= +primitive("message", message, 0); +@!@:message\_}{\.{\\message} primitive@> +primitive("errmessage", message, 1); +@!@:err\_message\_}{\.{\\errmessage} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case message: if (chr_code==0) print_esc("message"); + else print_esc("errmessage");@+break; + +@ @<Declare act...@>= +static void issue_message(void) +{@+int old_setting; /*holds |selector| setting*/ +int @!c; /*identifies \.{\\message} and \.{\\errmessage}*/ +str_number @!s; /*the message*/ +c=cur_chr;link(garbage)=scan_toks(false, true); +old_setting=selector;selector=new_string; +token_show(def_ref);selector=old_setting; +flush_list(def_ref); +str_room(1);s=make_string(); +if (c==0) @<Print string |s| on the terminal@>@; +else@<Print string |s| as an error message@>; +flush_string; +} + +@ @<Print string |s| on the terminal@>= +{@+if (term_offset+length(s) > max_print_line-2) print_ln(); +else if ((term_offset > 0)||(file_offset > 0)) print_char(' '); +slow_print(s);update_terminal; +} + +@ If \.{\\errmessage} occurs often in |scroll_mode|, without user-defined +\.{\\errhelp}, we don't want to give a long help message each time. So we +give a verbose explanation only once. + +@<Glob...@>= +static bool @!long_help_seen; /*has the long \.{\\errmessage} help been used?*/ + +@ @<Set init...@>=long_help_seen=false; + +@ @<Print string |s| as an error message@>= +{@+print_err("");slow_print(s); +if (err_help!=null) use_err_help=true; +else if (long_help_seen) help1("(That was another \\errmessage.)")@; +else{@+if (interaction < error_stop_mode) long_help_seen=true; + help4("This error message was generated by an \\errmessage",@/ + "command, so I can't give any explicit help.",@/ + "Pretend that you're Hercule Poirot: Examine all clues,",@/ +@^Poirot, Hercule@> + "and deduce the truth by order and method."); + } +error();use_err_help=false; +} + +@ The |error| routine calls on |give_err_help| if help is requested from +the |err_help| parameter. + +@p static void give_err_help(void) +{@+token_show(err_help); +} + +@ The \.{\\uppercase} and \.{\\lowercase} commands are implemented by +building a token list and then changing the cases of the letters in it. + +@<Cases of |main_control| that don't...@>= +any_mode(case_shift): shift_case();@+break; + +@ @<Put each...@>= +primitive("lowercase", case_shift, lc_code_base); +@!@:lowercase\_}{\.{\\lowercase} primitive@> +primitive("uppercase", case_shift, uc_code_base); +@!@:uppercase\_}{\.{\\uppercase} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case case_shift: if (chr_code==lc_code_base) print_esc("lowercase"); + else print_esc("uppercase");@+break; + +@ @<Declare act...@>= +static void shift_case(void) +{@+pointer b; /*|lc_code_base| or |uc_code_base|*/ +pointer @!p; /*runs through the token list*/ +halfword @!t; /*token*/ +eight_bits @!c; /*character code*/ +b=cur_chr;p=scan_toks(false, false);p=link(def_ref); +while (p!=null) + {@+@<Change the case of the token in |p|, if a change is appropriate@>; + p=link(p); + } +back_list(link(def_ref));free_avail(def_ref); /*omit reference count*/ +} + +@ When the case of a |chr_code| changes, we don't change the |cmd|. +We also change active characters, using the fact that +|cs_token_flag+active_base| is a multiple of~256. +@^data structure assumptions@> + +@<Change the case of the token in |p|, if a change is appropriate@>= +t=info(p); +if (t < cs_token_flag+single_base) + {@+c=t%256; + if (equiv(b+c)!=0) info(p)=t-c+equiv(b+c); + } + +@ We come finally to the last pieces missing from |main_control|, namely the +`\.{\\show}' commands that are useful when debugging. + +@<Cases of |main_control| that don't...@>= +any_mode(xray): show_whatever();@+break; + +@ @d show_code 0 /* \.{\\show} */ +@d show_box_code 1 /* \.{\\showbox} */ +@d show_the_code 2 /* \.{\\showthe} */ +@d show_lists 3 /* \.{\\showlists} */ + +@<Put each...@>= +primitive("show", xray, show_code); +@!@:show\_}{\.{\\show} primitive@> +primitive("showbox", xray, show_box_code); +@!@:show\_box\_}{\.{\\showbox} primitive@> +primitive("showthe", xray, show_the_code); +@!@:show\_the\_}{\.{\\showthe} primitive@> +primitive("showlists", xray, show_lists); +@!@:show\_lists\_}{\.{\\showlists} primitive@> + +@ @<Cases of |print_cmd_chr|...@>= +case xray: switch (chr_code) { + case show_box_code: print_esc("showbox");@+break; + case show_the_code: print_esc("showthe");@+break; + case show_lists: print_esc("showlists");@+break; + @<Cases of |xray| for |print_cmd_chr|@>@;@/ + default:print_esc("show"); + } @+break; + +@ @<Declare act...@>= +static void show_whatever(void) +{@+ +pointer p; /*tail of a token list to show*/ +small_number @!t; /*type of conditional being shown*/ +int @!m; /*upper bound on |fi_or_else| codes*/ +int @!l; /*line where that conditional began*/ +int @!n; /*level of \.{\\if...\\fi} nesting*/ +switch (cur_chr) { +case show_lists: {@+begin_diagnostic();show_activities(); + } @+break; +case show_box_code: @<Show the current contents of a box@>@;@+break; +case show_code: @<Show the current meaning of a token, then |goto common_ending|@>@; +@<Cases for |show_whatever|@>@;@/ +default:@<Show the current value of some parameter or register, then |goto common_ending|@>@; +} @/ +@<Complete a potentially long \.{\\show} command@>; +common_ending: if (interaction < error_stop_mode) + {@+help0;decr(error_count); + } +else if (tracing_online > 0) + {@+@t@>@;@/ + help3("This isn't an error message; I'm just \\showing something.",@/ + "Type `I\\show...' to show more (e.g., \\show\\cs,",@/ + "\\showthe\\count10, \\showbox255, \\showlists)."); + } +else{@+@t@>@;@/ + help5("This isn't an error message; I'm just \\showing something.",@/ + "Type `I\\show...' to show more (e.g., \\show\\cs,",@/ + "\\showthe\\count10, \\showbox255, \\showlists).",@/ + "And type `I\\tracingonline=1\\show...' to show boxes and",@/ + "lists on your terminal as well as in the transcript file."); + } +error(); +} + +@ @<Show the current meaning of a token...@>= +{@+get_token(); +if (interaction==error_stop_mode) wake_up_terminal; +print_nl("> "); +if (cur_cs!=0) + {@+sprint_cs(cur_cs);print_char('='); + } +print_meaning();goto common_ending; +} + +@ @<Cases of |print_cmd_chr|...@>= +case undefined_cs: print("undefined");@+break; +case call: case long_call: case outer_call: case long_outer_call: {@+n=cmd-call; + if (info(link(chr_code))==protected_token) n=n+4; + if (odd(n/4)) print_esc("protected"); + if (odd(n)) print_esc("long"); + if (odd(n/2)) print_esc("outer"); + if (n > 0) print_char(' '); + print("macro"); + } @+break; +case end_template: print_esc("outer endtemplate");@+break; + +@ @<Show the current contents of a box@>= +{@+scan_register_num();fetch_box(p);begin_diagnostic(); +print_nl("> \\box");print_int(cur_val);print_char('='); +if (p==null) print("void");@+else show_box(p); +} + +@ @<Show the current value of some parameter...@>= +{@+p=the_toks(); +if (interaction==error_stop_mode) wake_up_terminal; +print_nl("> ");token_show(temp_head); +flush_list(link(temp_head));goto common_ending; +} + +@ @<Complete a potentially long \.{\\show} command@>= +end_diagnostic(true);print_err("OK"); +@.OK@> +if (selector==term_and_log) if (tracing_online <= 0) + {@+selector=term_only;print(" (see the transcript file)"); + selector=term_and_log; + } + +@* Dumping and undumping the tables. +After \.{INITEX} has seen a collection of fonts and macros, it +can write all the necessary information on an auxiliary file so +that production versions of \TeX\ are able to initialize their +memory at high speed. The present section of the program takes +care of such output and input. We shall consider simultaneously +the processes of storing and restoring, +so that the inverse relation between them is clear. +@.INITEX@> + +The global variable |format_ident| is a string that is printed right +after the |banner| line when \TeX\ is ready to start. For \.{INITEX} this +string says simply `\.{(INITEX)}'; for other versions of \TeX\ it says, +for example, `\.{(preloaded format=plain 1982.11.19)}', showing the year, +month, and day that the format file was created. We have |format_ident==0| +before \TeX's tables are loaded. + +@<Glob...@>= +static str_number @!format_ident; + +@ @<Set init...@>= +format_ident=0; + +@ @<Initialize table entries...@>= +format_ident=s_no(" (INITEX)"); + +@ @<Declare act...@>= +#ifdef @!INIT +static void store_fmt_file(void) +{@+ +int j, @!k, @!l; /*all-purpose indices*/ +int @!p, @!q; /*all-purpose pointers*/ +int @!x; /*something to dump*/ +four_quarters @!w; /*four ASCII codes*/ +@<If dumping is not allowed, abort@>; +@<Create the |format_ident|, open the format file, and inform the user that dumping +has begun@>; +eqtb[dimen_base+hsize_code].i=hhsize; +eqtb[dimen_base+vsize_code].i=hvsize; +@<Dump constants for consistency check@>; +@<Dump the string pool@>; +@<Dump the dynamic memory@>; +@<Dump the table of equivalents@>; +@<Dump the font information@>; +@<Dump the hyphenation tables@>; +@<Dump a couple more things and the closing check word@>; +@<Close the format file@>; +eqtb[dimen_base+hsize_code].i=0; +eqtb[dimen_base+vsize_code].i=0; +} +#endif + +@ Corresponding to the procedure that dumps a format file, we have a function +that reads one in. The function returns |false| if the dumped format is +incompatible with the present \TeX\ table sizes, etc. + +@d too_small(X) {@+wake_up_terminal; + wterm_ln("---! Must increase the %s", X); +@.Must increase the x@> + goto bad_fmt; + } + +@p @t\4@>@<Declare the function called |open_fmt_file|@>@; +static bool load_fmt_file(void) +{@+ +int j, @!k; /*all-purpose indices*/ +int @!p, @!q; /*all-purpose pointers*/ +int @!x; /*something undumped*/ +four_quarters @!w; /*four ASCII codes*/ +@<Undump constants for consistency check@>; +@<Undump the string pool@>; +@<Undump the dynamic memory@>; +@<Undump the table of equivalents@>; +@<Undump the font information@>; +@<Undump the hyphenation tables@>; +@<Undump a couple more things and the closing check word@>; +return true; /*it worked!*/ +bad_fmt: wake_up_terminal; + wterm_ln("(Fatal format file error; I'm stymied)"); +@.Fatal format file error@> +return false; +} + +@ The user is not allowed to dump a format file unless |save_ptr==0|. +This condition implies that |cur_level==level_one|, hence +the |xeq_level| array is constant and it need not be dumped. + +@<If dumping is not allowed, abort@>= +if (save_ptr!=0) + {@+print_err("You can't dump inside a group"); +@.You can't dump...@> + help1("`{...\\dump}' is a no-no.");succumb; + } + +@ Format files consist of |memory_word| items, and we use the following +macros to dump words of different types: + +@d dump_wd(A) {@+fmt_file.d=A;put(fmt_file);@+} +@d dump_int(A) {@+fmt_file.d.i=A;put(fmt_file);@+} +@d dump_hh(A) {@+fmt_file.d.hh=A;put(fmt_file);@+} +@d dump_qqqq(A) {@+fmt_file.d.qqqq=A;put(fmt_file);@+} + +@<Glob...@>= +static word_file @!fmt_file; /*for input or output of format information*/ + +@ The inverse macros are slightly more complicated, since we need to check +the range of the values we are reading in. We say `|undump(a)(b)(x)|' to +read an integer value |x| that is supposed to be in the range |a <= x <= b|. + +@d undump_wd(A) {@+get(fmt_file);A=fmt_file.d;@+} +@d undump_int(A) {@+get(fmt_file);A=fmt_file.d.i;@+} +@d undump_hh(A) {@+get(fmt_file);A=fmt_file.d.hh;@+} +@d undump_qqqq(A) {@+get(fmt_file);A=fmt_file.d.qqqq;@+} +@d undump(A, B, C) {@+undump_int(x);if ((x < A)||(x > B)) goto bad_fmt;@+else C=x;@+} +@d undump_size(A, B, C, D) {@+undump_int(x); + if (x < A) goto bad_fmt;if (x > B) too_small(C)@;@+else D=x;@+} + +@ The next few sections of the program should make it clear how we use the +dump/undump macros. + +@<Dump constants for consistency check@>= +dump_int(0);@/ +@<Dump the \eTeX\ state@>@/ +dump_int(mem_bot);@/ +dump_int(mem_top);@/ +dump_int(eqtb_size);@/ +dump_int(hash_prime);@/ +dump_int(hyph_size) + +@ Sections of a \.{WEB} program that are ``commented out'' still contribute +strings to the string pool; therefore \.{INITEX} and \TeX\ will have +the same strings. (And it is, of course, a good thing that they do.) +@.WEB@> +@^string pool@> + +@<Undump constants for consistency check@>= +x=fmt_file.d.i; +if (x!=0) goto bad_fmt; /*check that strings are the same*/ +@/@<Undump the \eTeX\ state@>@/ +undump_int(x); +if (x!=mem_bot) goto bad_fmt; +undump_int(x); +if (x!=mem_top) goto bad_fmt; +undump_int(x); +if (x!=eqtb_size) goto bad_fmt; +undump_int(x); +if (x!=hash_prime) goto bad_fmt; +undump_int(x); +if (x!=hyph_size) goto bad_fmt + +@ @d dump_four_ASCII + w.b0=qi(so(str_pool[k]));w.b1=qi(so(str_pool[k+1])); + w.b2=qi(so(str_pool[k+2]));w.b3=qi(so(str_pool[k+3])); + dump_qqqq(w) + +@<Dump the string pool@>= +dump_int(pool_ptr); +dump_int(str_ptr); +for (k=0; k<=str_ptr; k++) dump_int(str_start[k]); +k=0; +while (k+4 < pool_ptr) + {@+dump_four_ASCII;k=k+4; + } +k=pool_ptr-4;dump_four_ASCII; +print_ln();print_int(str_ptr);print(" strings of total length "); +print_int(pool_ptr) + +@ @d undump_four_ASCII + undump_qqqq(w); + str_pool[k]=si(qo(w.b0));str_pool[k+1]=si(qo(w.b1)); + str_pool[k+2]=si(qo(w.b2));str_pool[k+3]=si(qo(w.b3)) + +@<Undump the string pool@>= +undump_size(0, pool_size,"string pool size", pool_ptr); +undump_size(0, max_strings,"max strings", str_ptr); +for (k=0; k<=str_ptr; k++) undump(0, pool_ptr, str_start[k]); +k=0; +while (k+4 < pool_ptr) + {@+undump_four_ASCII;k=k+4; + } +k=pool_ptr-4;undump_four_ASCII; +init_str_ptr=str_ptr;init_pool_ptr=pool_ptr + +@ By sorting the list of available spaces in the variable-size portion of +|mem|, we are usually able to get by without having to dump very much +of the dynamic memory. + +We recompute |var_used| and |dyn_used|, so that \.{INITEX} dumps valid +information even when it has not been gathering statistics. + +@<Dump the dynamic memory@>= +sort_avail();var_used=0; +dump_int(lo_mem_max);dump_int(rover); +if (eTeX_ex) for (k=int_val; k<=tok_val; k++) dump_int(sa_root[k]); +p=mem_bot;q=rover;x=0; +@/do@+{for (k=p; k<=q+1; k++) dump_wd(mem[k]); +x=x+q+2-p;var_used=var_used+q-p; +p=q+node_size(q);q=rlink(q); +}@+ while (!(q==rover)); +var_used=var_used+lo_mem_max-p;dyn_used=mem_end+1-hi_mem_min;@/ +for (k=p; k<=lo_mem_max; k++) dump_wd(mem[k]); +x=x+lo_mem_max+1-p; +dump_int(hi_mem_min);dump_int(avail); +for (k=hi_mem_min; k<=mem_end; k++) dump_wd(mem[k]); +x=x+mem_end+1-hi_mem_min; +p=avail; +while (p!=null) + {@+decr(dyn_used);p=link(p); + } +dump_int(var_used);dump_int(dyn_used); +print_ln();print_int(x); +print(" memory locations dumped; current usage is "); +print_int(var_used);print_char('&');print_int(dyn_used) + +@ @<Undump the dynamic memory@>= +undump(lo_mem_stat_max+1000, hi_mem_stat_min-1, lo_mem_max); +undump(lo_mem_stat_max+1, lo_mem_max, rover); +if (eTeX_ex) for (k=int_val; k<=tok_val; k++) + undump(null, lo_mem_max, sa_root[k]); +p=mem_bot;q=rover; +@/do@+{for (k=p; k<=q+1; k++) undump_wd(mem[k]); +p=q+node_size(q); +if ((p > lo_mem_max)||((q >= rlink(q))&&(rlink(q)!=rover))) goto bad_fmt; +q=rlink(q); +}@+ while (!(q==rover)); +for (k=p; k<=lo_mem_max; k++) undump_wd(mem[k]); +if (mem_min < mem_bot-2) /*make more low memory available*/ + {@+p=llink(rover);q=mem_min+1; + link(mem_min)=null;info(mem_min)=null; /*we don't use the bottom word*/ + rlink(p)=q;llink(rover)=q;@/ + rlink(q)=rover;llink(q)=p;link(q)=empty_flag; + node_size(q)=mem_bot-q; + } +undump(lo_mem_max+1, hi_mem_stat_min, hi_mem_min); +undump(null, mem_top, avail);mem_end=mem_top; +for (k=hi_mem_min; k<=mem_end; k++) undump_wd(mem[k]); +undump_int(var_used);undump_int(dyn_used) + +@ @<Dump the table of equivalents@>= +@<Dump regions 1 to 4 of |eqtb|@>; +@<Dump regions 5 and 6 of |eqtb|@>; +dump_int(par_loc);dump_int(write_loc);@/ +@<Dump the hash table@>@; + +@ @<Undump the table of equivalents@>= +@<Undump regions 1 to 6 of |eqtb|@>; +undump(hash_base, frozen_control_sequence, par_loc); +par_token=cs_token_flag+par_loc;@/ +undump(hash_base, frozen_control_sequence, write_loc);@/ +@<Undump the hash table@>@; + +@ The table of equivalents usually contains repeated information, so we dump it +in compressed form: The sequence of $n+2$ values $(n,x_1,\ldots,x_n,m)$ in the +format file represents $n+m$ consecutive entries of |eqtb|, with |m| extra +copies of $x_n$, namely $(x_1,\ldots,x_n,x_n,\ldots,x_n)$. + +@<Dump regions 1 to 4 of |eqtb|@>= +k=active_base; +@/do@+{j=k; +while (j < int_base-1) + {@+if ((equiv(j)==equiv(j+1))&&(eq_type(j)==eq_type(j+1))&&@| + (eq_level(j)==eq_level(j+1))) goto found1; + incr(j); + } +l=int_base;goto done1; /*|j==int_base-1|*/ +found1: incr(j);l=j; +while (j < int_base-1) + {@+if ((equiv(j)!=equiv(j+1))||(eq_type(j)!=eq_type(j+1))||@| + (eq_level(j)!=eq_level(j+1))) goto done1; + incr(j); + } +done1: dump_int(l-k); +while (k < l) + {@+dump_wd(eqtb[k]);incr(k); + } +k=j+1;dump_int(k-l); +}@+ while (!(k==int_base)) + +@ @<Dump regions 5 and 6 of |eqtb|@>= +@/do@+{j=k; +while (j < eqtb_size) + {@+if (eqtb[j].i==eqtb[j+1].i) goto found2; + incr(j); + } +l=eqtb_size+1;goto done2; /*|j==eqtb_size|*/ +found2: incr(j);l=j; +while (j < eqtb_size) + {@+if (eqtb[j].i!=eqtb[j+1].i) goto done2; + incr(j); + } +done2: dump_int(l-k); +while (k < l) + {@+dump_wd(eqtb[k]);incr(k); + } +k=j+1;dump_int(k-l); +}@+ while (!(k > eqtb_size)) + +@ @<Undump regions 1 to 6 of |eqtb|@>= +k=active_base; +@/do@+{undump_int(x); +if ((x < 1)||(k+x > eqtb_size+1)) goto bad_fmt; +for (j=k; j<=k+x-1; j++) undump_wd(eqtb[j]); +k=k+x; +undump_int(x); +if ((x < 0)||(k+x > eqtb_size+1)) goto bad_fmt; +for (j=k; j<=k+x-1; j++) eqtb[j]=eqtb[k-1]; +k=k+x; +}@+ while (!(k > eqtb_size)) + +@ A different scheme is used to compress the hash table, since its lower +region is usually sparse. When |text(p)!=0| for |p <= hash_used|, we output +two words, |p| and |hash[p]|. The hash table is, of course, densely packed +for |p >= hash_used|, so the remaining entries are output in a~block. + +@<Dump the hash table@>= +dump_int(hash_used);cs_count=frozen_control_sequence-1-hash_used; +for (p=hash_base; p<=hash_used; p++) if (text(p)!=0) + {@+dump_int(p);dump_hh(hash[p]);incr(cs_count); + } +for (p=hash_used+1; p<=undefined_control_sequence-1; p++) dump_hh(hash[p]); +dump_int(cs_count);@/ +print_ln();print_int(cs_count);print(" multiletter control sequences") + +@ @<Undump the hash table@>= +undump(hash_base, frozen_control_sequence, hash_used);p=hash_base-1; +@/do@+{undump(p+1, hash_used, p);undump_hh(hash[p]); +}@+ while (!(p==hash_used)); +for (p=hash_used+1; p<=undefined_control_sequence-1; p++) undump_hh(hash[p]); +undump_int(cs_count) + +@ @<Dump the font information@>= +dump_int(fmem_ptr); +for (k=0; k<=fmem_ptr-1; k++) dump_wd(font_info[k]); +dump_int(font_ptr); +for (k=null_font; k<=font_ptr; k++) + @<Dump the array info for internal font number |k|@>; +print_ln();print_int(fmem_ptr-7);print(" words of font info for "); +print_int(font_ptr-font_base);print(" preloaded font"); +if (font_ptr!=font_base+1) print_char('s') + +@ @<Undump the font information@>= +undump_size(7, font_mem_size,"font mem size", fmem_ptr); +for (k=0; k<=fmem_ptr-1; k++) undump_wd(font_info[k]); +undump_size(font_base, font_max,"font max", font_ptr); +for (k=null_font; k<=font_ptr; k++) + @<Undump the array info for internal font number |k|@>@; + +@ @<Dump the array info for internal font number |k|@>= +{@+dump_qqqq(font_check[k]); +dump_int(font_size[k]); +dump_int(font_dsize[k]); +dump_int(font_params[k]);@/ +dump_int(hyphen_char[k]); +dump_int(skew_char[k]);@/ +dump_int(font_name[k]); +dump_int(font_area[k]);@/ +dump_int(font_bc[k]); +dump_int(font_ec[k]);@/ +dump_int(char_base[k]); +dump_int(width_base[k]); +dump_int(height_base[k]);@/ +dump_int(depth_base[k]); +dump_int(italic_base[k]); +dump_int(lig_kern_base[k]);@/ +dump_int(kern_base[k]); +dump_int(exten_base[k]); +dump_int(param_base[k]);@/ +dump_int(font_glue[k]);@/ +dump_int(bchar_label[k]); +dump_int(font_bchar[k]); +dump_int(font_false_bchar[k]);@/ +print_nl("\\font");printn_esc(font_id_text(k));print_char('='); +printn_file_name(font_name[k], font_area[k],empty_string); +if (font_size[k]!=font_dsize[k]) + {@+print(" at ");print_scaled(font_size[k]);print("pt"); + } +} + +@ @<Undump the array info for internal font number |k|@>= +{@+undump_qqqq(font_check[k]);@/ +undump_int(font_size[k]); +undump_int(font_dsize[k]); +undump(min_halfword, max_halfword, font_params[k]);@/ +undump_int(hyphen_char[k]); +undump_int(skew_char[k]);@/ +undump(0, str_ptr, font_name[k]); +undump(0, str_ptr, font_area[k]);@/ +undump(0, 255, font_bc[k]); +undump(0, 255, font_ec[k]);@/ +undump_int(char_base[k]); +undump_int(width_base[k]); +undump_int(height_base[k]);@/ +undump_int(depth_base[k]); +undump_int(italic_base[k]); +undump_int(lig_kern_base[k]);@/ +undump_int(kern_base[k]); +undump_int(exten_base[k]); +undump_int(param_base[k]);@/ +undump(min_halfword, lo_mem_max, font_glue[k]);@/ +undump(0, fmem_ptr-1, bchar_label[k]); +undump(min_quarterword, non_char, font_bchar[k]); +undump(min_quarterword, non_char, font_false_bchar[k]); +} + +@ @<Dump the hyphenation tables@>= +dump_int(hyph_count); +for (k=0; k<=hyph_size; k++) if (hyph_word[k]!=0) + {@+dump_int(k);dump_int(hyph_word[k]);dump_int(hyph_list[k]); + } +print_ln();print_int(hyph_count);print(" hyphenation exception"); +if (hyph_count!=1) print_char('s'); +if (trie_not_ready) init_trie(); +dump_int(trie_max); +for (k=0; k<=trie_max; k++) dump_hh(trie[k]); +dump_int(trie_op_ptr); +for (k=1; k<=trie_op_ptr; k++) + {@+dump_int(hyf_distance[k]); + dump_int(hyf_num[k]); + dump_int(hyf_next[k]); + } +print_nl("Hyphenation trie of length ");print_int(trie_max); +@.Hyphenation trie...@> +print(" has ");print_int(trie_op_ptr);print(" op"); +if (trie_op_ptr!=1) print_char('s'); +print(" out of ");print_int(trie_op_size); +for (k=255; k>=0; k--) if (trie_used[k] > min_quarterword) + {@+print_nl(" ");print_int(qo(trie_used[k])); + print(" for language ");print_int(k); + dump_int(k);dump_int(qo(trie_used[k])); + } + +@ Only ``nonempty'' parts of |op_start| need to be restored. + +@<Undump the hyphenation tables@>= +undump(0, hyph_size, hyph_count); +for (k=1; k<=hyph_count; k++) + {@+undump(0, hyph_size, j); + undump(0, str_ptr, hyph_word[j]); + undump(min_halfword, max_halfword, hyph_list[j]); + } +undump_size(0, trie_size,"trie size", j); +#ifdef @!INIT +trie_max=j; +#endif +for (k=0; k<=j; k++) undump_hh(trie[k]); +undump_size(0, trie_op_size,"trie op size", j); +#ifdef @!INIT +trie_op_ptr=j; +#endif +for (k=1; k<=j; k++) + {@+undump(0, 63, hyf_distance[k]); /*a |small_number|*/ + undump(0, 63, hyf_num[k]); + undump(min_quarterword, max_quarterword, hyf_next[k]); + } +#ifdef @!INIT +for (k=0; k<=255; k++) trie_used[k]=min_quarterword; +#endif +@;@/ +k=256; +while (j > 0) + {@+undump(0, k-1, k);undump(1, j, x); +#ifdef @!INIT +trie_used[k]=qi(x); +#endif +@;@/ + j=j-x;op_start[k]=qo(j); + } +#ifdef @!INIT +trie_not_ready=false +#endif + +@ We have already printed a lot of statistics, so we set |tracing_stats=0| +to prevent them from appearing again. + +@<Dump a couple more things and the closing check word@>= +dump_int(interaction);dump_int(format_ident);dump_int(69069); +tracing_stats=0 + +@ @<Undump a couple more things and the closing check word@>= +undump(batch_mode, error_stop_mode, interaction); +undump(0, str_ptr, format_ident); +undump_int(x); +if ((x!=69069)||eof(fmt_file)) goto bad_fmt + +@ @<Create the |format_ident|...@>= +selector=new_string; +print(" (preloaded format=");printn(job_name);print_char(' '); +print_int(year);print_char('.'); +print_int(month);print_char('.');print_int(day);print_char(')'); +if (interaction==batch_mode) selector=log_only; +else selector=term_and_log; +str_room(1); +format_ident=make_string(); +pack_job_name(format_extension); +while (!w_open_out(&fmt_file)) + prompt_file_name("format file name", format_extension); +print_nl("Beginning to dump on file "); +@.Beginning to dump...@> +slow_print(w_make_name_string(&fmt_file));flush_string; +print_nl("");slow_print(format_ident) + +@ @<Close the format file@>= +w_close(&fmt_file) + +@* The main program. +This is it: the part of \TeX\ that executes all those procedures we have +written. + +Well---almost. Let's leave space for a few more routines that we may +have forgotten. + +@p @<Last-minute procedures@>@; + +@ We have noted that there are two versions of \TeX82. One, called \.{INITEX}, +@.INITEX@> +has to be run first; it initializes everything from scratch, without +reading a format file, and it has the capability of dumping a format file. +The other one is called `\.{VIRTEX}'; it is a ``virgin'' program that needs +@.VIRTEX@> +to input a format file in order to get started. \.{VIRTEX} typically has +more memory capacity than \.{INITEX}, because it does not need the space +consumed by the auxiliary hyphenation tables and the numerous calls on +|primitive|, etc. + +The \.{VIRTEX} program cannot read a format file instantaneously, of course; +the best implementations therefore allow for production versions of \TeX\ that +not only avoid the loading routine for \PASCAL\ object code, they also have +a format file pre-loaded. This is impossible to do if we stick to standard +\PASCAL; but there is a simple way to fool many systems into avoiding the +initialization, as follows:\quad(1)~We declare a global integer variable +called |ready_already|. The probability is negligible that this +variable holds any particular value like 314159 when \.{VIRTEX} is first +loaded.\quad(2)~After we have read in a format file and initialized +everything, we set |ready_already=314159|.\quad(3)~Soon \.{VIRTEX} +will print `\.*', waiting for more input; and at this point we +interrupt the program and save its core image in some form that the +operating system can reload speedily.\quad(4)~When that core image is +activated, the program starts again at the beginning; but now +|ready_already==314159| and all the other global variables have +their initial values too. The former chastity has vanished! + +In other words, if we allow ourselves to test the condition +|ready_already==314159|, before |ready_already| has been +assigned a value, we can avoid the lengthy initialization. Dirty tricks +rarely pay off so handsomely. +@^dirty \PASCAL@> +@^system dependencies@> + +On systems that allow such preloading, the standard program called \.{TeX} +should be the one that has \.{plain} format preloaded, since that agrees +with {\sl The \TeX book}. Other versions, e.g., \.{AmSTeX}, should also +@:TeXbook}{\sl The \TeX book@> +@.AmSTeX@> +@.plain@> +be provided for commonly used formats. + +@<Glob...@>= +static int @!ready_already; /*a sacrifice of purity for economy*/ + +@ Now this is really it: \TeX\ starts and ends here. + +The initial test involving |ready_already| should be deleted if the +\PASCAL\ runtime system is smart enough to detect such a ``mistake.'' +@^system dependencies@> + +@p +int main(int argc, char *argv[]) {@! /*|start_here|*/ + main_init(argc, argv); /* k\TeX\ */ +history=fatal_error_stop; /*in case we quit during initialization*/ +t_open_out; /*open the terminal for output*/ +if (ready_already==314159) goto start_of_TEX; +@<Check the ``constant'' values...@>@; +if (bad > 0) + {@+wterm_ln("Ouch---my internal constants have been clobbered!" + "---case %d", bad); +@.Ouch...clobbered@> + exit(0); + } +get_strings_started(); +initialize(); /*set global variables to their starting values*/ +#ifdef @!INIT +if (iniversion) +{ init_prim(); /*call |primitive| for each primitive*/ + init_str_ptr=str_ptr;init_pool_ptr=pool_ptr;fix_date_and_time(); } +#endif +ready_already=314159; +start_of_TEX: @<Initialize the output routines@>; +@<Get the first line of input and prepare to start@>; +history=spotless; /*ready to go!*/ +hhsize=hsize; hvsize=vsize;@/ +hint_open(); main_control(); hint_close(); /*come to life*/ +final_cleanup(); /*prepare for death*/ +close_files_and_terminate(); +ready_already=0; +return 0; } + +@ Here we do whatever is needed to complete \TeX's job gracefully on the +local operating system. The code here might come into play after a fatal +error; it must therefore consist entirely of ``safe'' operations that +cannot produce error messages. For example, it would be a mistake to call +|str_room| or |make_string| at this time, because a call on |overflow| +might lead to an infinite loop. +@^system dependencies@> + +Actually there's one way to get error messages, via |prepare_mag|; +but that can't cause infinite recursion. +@^recursion@> + +This program doesn't bother to close the input files that may still be open. + +@<Last-minute...@>= +static void close_files_and_terminate(void) +{@+int k; /*all-purpose index*/ +@<Finish the extensions@>; +#ifdef @!STAT +if (tracing_stats > 0) @<Output statistics about this job@>;@; +#endif +wake_up_terminal; +if (log_opened) + {@+wlog_cr;a_close(&log_file);selector=selector-2; + if (selector==term_only) + {@+print_nl("Transcript written on "); +@.Transcript written...@> + slow_print(log_name);print_char('.');print_nl(""); + } + } +} + +@ The present section goes directly to the log file instead of using +|print| commands, because there's no need for these strings to take +up |str_pool| memory when a non-{\bf stat} version of \TeX\ is being used. + +@<Output statistics...@>= +if (log_opened) + {@+wlog_ln(" "); + wlog_ln("Here is how much of TeX's memory you used:"); +@.Here is how much...@> + wlog(" %d string", str_ptr-init_str_ptr); + if (str_ptr!=init_str_ptr+1) wlog( "s" ); + wlog_ln( " out of %d", max_strings-init_str_ptr);@/ + wlog_ln( " %d string characters out of %d", pool_ptr-init_pool_ptr, + pool_size-init_pool_ptr);@/ + wlog_ln(" %d words of memory out of %d", lo_mem_max-mem_min+mem_end-hi_mem_min+2,@| + mem_end+1-mem_min);@/ + wlog_ln(" %d multiletter control sequences out of %d", cs_count, hash_size);@/ + wlog(" %d words of font info for %d font", fmem_ptr, font_ptr-font_base); + if (font_ptr!=font_base+1) wlog("s"); + wlog_ln( ", out of %d for %d", font_mem_size, font_max-font_base);@/ + wlog(" %d hyphenation exception", hyph_count); + if (hyph_count!=1) wlog("s"); + wlog_ln( " out of %d", hyph_size);@/ + wlog_ln(" %di,%dn,%dp,%db,%ds stack positions out of %di,%dn,%dp,%db,%ds", + max_in_stack, max_nest_stack,@| + max_param_stack,@| + max_buf_stack+1,@| + max_save_stack+6,@| + stack_size, + nest_size, + param_size, + buf_size, + save_size ); + } + +@ We get to the |final_cleanup| routine when \.{\\end} or \.{\\dump} has +been scanned and |its_all_over|\kern-2pt. + +@<Last-minute...@>= +static void final_cleanup(void) +{@+ +int c; /*0 for \.{\\end}, 1 for \.{\\dump}*/ +c=cur_chr; +if (job_name==0) open_log_file(); +while (input_ptr > 0) + if (state==token_list) end_token_list();@+else end_file_reading(); +while (open_parens > 0) + {@+print(" )");decr(open_parens); + } +if (cur_level > level_one) + {@+print_nl("(");print_esc("end occurred "); + print("inside a group at level "); +@:end\_}{\.{(\\end occurred...)}@> + print_int(cur_level-level_one);print_char(')'); + if (eTeX_ex) show_save_groups(); + } +while (cond_ptr!=null) + {@+print_nl("(");print_esc("end occurred "); + print("when ");print_cmd_chr(if_test, cur_if); + if (if_line!=0) + {@+print(" on line ");print_int(if_line); + } + print(" was incomplete)"); + if_line=if_line_field(cond_ptr); + cur_if=subtype(cond_ptr);temp_ptr=cond_ptr; + cond_ptr=link(cond_ptr);free_node(temp_ptr, if_node_size); + } +if (history!=spotless) + if (((history==warning_issued)||(interaction < error_stop_mode))) + if (selector==term_and_log) + {@+selector=term_only; + print_nl("(see the transcript file for additional information)"); +@.see the transcript file...@> + selector=term_and_log; + } +if (c==1) + { +#ifdef @!INIT +for (c=top_mark_code; c<=split_bot_mark_code; c++) + if (cur_mark[c]!=null) delete_token_ref(cur_mark[c]); + if (last_glue!=max_halfword) delete_glue_ref(last_glue); + store_fmt_file();return; +#endif + print_nl("(\\dump is performed only by INITEX)");return; +@:dump\_}{\.{\\dump...only by INITEX}@> + } +} + +@ @<Last-minute...@>= +#ifdef @!INIT +static void init_prim(void) /*initialize all the primitives*/ +{@+no_new_control_sequence=false; +first=0; +@<Put each...@>; +no_new_control_sequence=true; +} +#endif + +@ When we begin the following code, \TeX's tables may still contain garbage; +the strings might not even be present. Thus we must proceed cautiously to get +bootstrapped in. + +But when we finish this part of the program, \TeX\ is ready to call on the +|main_control| routine to do its work. + +@<Get the first line...@>= +{@+@<Initialize the input routines@>; +@<Enable \eTeX, if requested@>@;@/ +if ((format_ident==0)||(buffer[loc]=='&')) + {@+if (format_ident!=0) initialize(); /*erase preloaded format*/ + if (!open_fmt_file()) exit(0); + if (!load_fmt_file()) + {@+w_close(&fmt_file);exit(0); + } + w_close(&fmt_file); + while ((loc < limit)&&(buffer[loc]==' ')) incr(loc); + } +if (eTeX_ex) wterm_ln("entering extended mode"); +if (end_line_char_inactive) decr(limit); +else buffer[limit]=end_line_char; +fix_date_and_time();@/ +@<Initialize the print |selector|...@>; +if ((loc < limit)&&(cat_code(buffer[loc])!=escape)) start_input(); + /*\.{\\input} assumed*/ +} + +@* Debugging. +Once \TeX\ is working, you should be able to diagnose most errors with +the \.{\\show} commands and other diagnostic features. But for the initial +stages of debugging, and for the revelation of really deep mysteries, you +can compile \TeX\ with a few more aids, including the \PASCAL\ runtime +checks and its debugger. An additional routine called |debug_help| +will also come into play when you type `\.D' after an error message; +|debug_help| also occurs just before a fatal error causes \TeX\ to succumb. +@^debugging@> +@^system dependencies@> + +The interface to |debug_help| is primitive, but it is good enough when used +with a \PASCAL\ debugger that allows you to set breakpoints and to read +variables and change their values. After getting the prompt `\.{debug \#}', you +type either a negative number (this exits |debug_help|), or zero (this +goes to a location where you can set a breakpoint, thereby entering into +dialog with the \PASCAL\ debugger), or a positive number |m| followed by +an argument |n|. The meaning of |m| and |n| will be clear from the +program below. (If |m==13|, there is an additional argument, |l|.) +@.debug \#@> + +@<Last-minute...@>= +#ifdef @!DEBUG +static void debug_help(void) /*routine to display various things*/ +{@+ +int k, @!l, @!m, @!n; +loop{@+wake_up_terminal; + print_nl("debug # (-1 to exit):");update_terminal; +@.debug \#@> + if (fscanf(term_in.f," %d",&m)<1 || + m < 0) return; + else if (m==0) + {@+goto breakpoint; /*go to every label at least once*/ + breakpoint: m=0; /*'BREAKPOINT'*/ + } + else{@+fscanf(term_in.f," %d",&n); + switch (m) { + @t\4@>@<Numbered cases for |debug_help|@>@; + default:print("?"); + } + } + } +} +#endif + +@ @<Numbered cases...@>= +case 1: print_word(mem[n]);@+break; /*display |mem[n]| in all forms*/ +case 2: print_int(info(n));@+break; +case 3: print_int(link(n));@+break; +case 4: print_word(eqtb[n]);@+break; +case 5: print_word(font_info[n]);@+break; +case 6: print_word(save_stack[n]);@+break; +case 7: show_box(n);@+break; + /*show a box, abbreviated by |show_box_depth| and |show_box_breadth|*/ +case 8: {@+breadth_max=10000;depth_threshold=pool_size-pool_ptr-10; + show_node_list(n); /*show a box in its entirety*/ + } @+break; +case 9: show_token_list(n, null, 1000);@+break; +case 10: slow_print(n);@+break; +case 11: check_mem(n > 0);@+break; /*check wellformedness; print new busy locations if |n > 0|*/ +case 12: search_mem(n);@+break; /*look for pointers to |n|*/ +case 13: {@+fscanf(term_in.f," %d",&l);print_cmd_chr(n, l); + } @+break; +case 14: for (k=0; k<=n; k++) printn(buffer[k]);@+break; +case 15: {@+font_in_short_display=null_font;short_display(n); + } @+break; +case 16: panicking=!panicking;@+break; + +@* Extensions. +The program above includes a bunch of ``hooks'' that allow further +capabilities to be added without upsetting \TeX's basic structure. +Most of these hooks are concerned with ``whatsit'' nodes, which are +intended to be used for special purposes; whenever a new extension to +\TeX\ involves a new kind of whatsit node, a corresponding change needs +to be made to the routines below that deal with such nodes, +but it will usually be unnecessary to make many changes to the +other parts of this program. + +In order to demonstrate how extensions can be made, we shall treat +`\.{\\write}', `\.{\\openout}', `\.{\\closeout}', `\.{\\immediate}', +`\.{\\special}', and `\.{\\setlanguage}' as if they were extensions. +These commands are actually primitives of \TeX, and they should +appear in all implementations of the system; but let's try to imagine +that they aren't. Then the program below illustrates how a person +could add them. + +Sometimes, of course, an extension will require changes to \TeX\ itself; +no system of hooks could be complete enough for all conceivable extensions. +The features associated with `\.{\\write}' are almost all confined to the +following paragraphs, but there are small parts of the |print_ln| and +|print_char| procedures that were introduced specifically to \.{\\write} +characters. Furthermore one of the token lists recognized by the scanner +is a |write_text|; and there are a few other miscellaneous places where we +have already provided for some aspect of \.{\\write}. The goal of a \TeX\ +extender should be to minimize alterations to the standard parts of the +program, and to avoid them completely if possible. He or she should also +be quite sure that there's no easy way to accomplish the desired goals +with the standard features that \TeX\ already has. ``Think thrice before +extending,'' because that may save a lot of work, and it will also keep +incompatible extensions of \TeX\ from proliferating. +@^system dependencies@> +@^extensions to \TeX@> + +@ First let's consider the format of whatsit nodes that are used to represent +the data associated with \.{\\write} and its relatives. Recall that a whatsit +has |type==whatsit_node|, and the |subtype| is supposed to distinguish +different kinds of whatsits. Each node occupies two or more words; the +exact number is immaterial, as long as it is readily determined from the +|subtype| or other data. + +We shall introduce five |subtype| values here, corresponding to the +control sequences \.{\\openout}, \.{\\write}, \.{\\closeout}, \.{\\special}, and +\.{\\setlanguage}. The second word of I/O whatsits has a |write_stream| field +that identifies the write-stream number (0 to 15, or 16 for out-of-range and +positive, or 17 for out-of-range and negative). +In the case of \.{\\write} and \.{\\special}, there is also a field that +points to the reference count of a token list that should be sent. In the +case of \.{\\openout}, we need three words and three auxiliary subfields +to hold the string numbers for name, area, and extension. + +@d write_node_size 2 /*number of words in a write/whatsit node*/ +@d open_node_size 3 /*number of words in an open/whatsit node*/ +@d open_node 0 /*|subtype| in whatsits that represent files to \.{\\openout}*/ +@d write_node 1 /*|subtype| in whatsits that represent things to \.{\\write}*/ +@d close_node 2 /*|subtype| in whatsits that represent streams to \.{\\closeout}*/ +@d special_node 3 /*|subtype| in whatsits that represent \.{\\special} things*/ +@d language_node 4 /*|subtype| in whatsits that change the current language*/ +@d what_lang(A) link(A+1) /*language number, in the range |0 dotdot 255|*/ +@d what_lhm(A) type(A+1) /*minimum left fragment, in the range |1 dotdot 63|*/ +@d what_rhm(A) subtype(A+1) /*minimum right fragment, in the range |1 dotdot 63|*/ +@d write_tokens(A) link(A+1) /*reference count of token list to write*/ +@d write_stream(A) info(A+1) /*stream number (0 to 17)*/ +@d open_name(A) link(A+1) /*string number of file name to open*/ +@d open_area(A) info(A+2) /*string number of file area for |open_name|*/ +@d open_ext(A) link(A+2) /*string number of file extension for |open_name|*/ @# + +@d par_node 6 /*|subtype| that records the change of a parameter*/ +@d par_node_size 3 /* number of memory words in a |par_node| */ +@d par_type(A) type(A+1) /* type of parameter */ +@d int_type 0 /* type of an |int_par| node */ +@d dimen_type 1 /* type of an |dimen_par| node */ +@d glue_type 2 /* type of an |glue_par| node */ +@d par_number(A) subtype(A+1) /* the parameter number */ +@d par_value(A) mem[A+2] /* the parameter value */@# + +@d graf_node 7 /*|subtype| that records a paragraph*/ +@d graf_node_size 5 /* number of memory words in a |graf_node| */ +@d graf_penalty(A) mem[A+1].i /* the final penalty */ +@d graf_extent(A) link(A+3) /* the extent */@# +@d graf_params(A) info(A+4) /* list of parameter nodes */ +@d graf_list(A) link(A+4) /* list of content nodes */ + +@d disp_node 8 /*|subtype| that records a math display*/ +@d disp_node_size 3 /* number of memory words in a |disp_node| */ +@d display_left(A) type(A+1) /* 1=left 0=right */ +@d display_no_bs(A) subtype(A+1) /* |prev_depth==ignore_depth| */ +@d display_params(A) link(A+1) /* list of parameter nodes */ +@d display_formula(A) link(A+2) /* formula list */ +@d display_eqno(A) info(A+2) /* box with equation number */@# + +@d baseline_node 9 /*|subtype| that records a |baseline_skip| */ +@d baseline_node_size small_node_size /* This is 2; we will convert baseline nodes to glue nodes */ +@d baseline_node_no(A) mem[A+1].i /* baseline reference */@# + +@d image_node 10 /*|subtype| that records an image */ +@d image_node_size 9 /* width, depth, height, |shift_amount| like a hbox */ +@d image_width(A) width(A) /*width of image */ +@d image_height(A) height(A) /*height of image */ +@d image_depth(A) depth(A) /* depth of image==zero */ +@d image_no(A) mem[A+4].i /* the section number */ +@d image_stretch(A) mem[A+5].sc /*stretchability of image */ +@d image_shrink(A) mem[A+6].sc /*shrinkability of image */ +@d image_stretch_order(A) stretch_order(A+7) +@d image_shrink_order(A) shrink_order(A+7) +@d image_name(A) link(A+7) /*string number of file name */ +@d image_area(A) info(A+8) /*string number of file area */ +@d image_ext(A) link(A+8) /*string number of file extension */@# + +@d hpack_node 12 /* a hlist that needs to go to hpack */ +@d vpack_node 13 /* a vlist that needs to go to vpackage */ +@d pack_node_size box_node_size /* a box node up to |list_ptr|*/ +@d pack_m(A) type(A+list_offset) /* either additional or exactly */ +@d pack_limit(A) mem[(A)+1+list_offset].sc /* depth limit in |vpack| */ +@d pack_extent(A) link(A+2+list_offset) /* extent */@# + +@d hset_node 14 /* represents a hlist that needs |glue_set| */ +@d vset_node 15 /* represents a vlist that needs |glue_set| */ +@d set_node_size box_node_size /* up to |list_ptr| like a box node */ +@d set_stretch_order glue_sign +@d set_shrink_order glue_order +@d set_stretch(A) mem[(A)+1+list_offset].sc /* replaces |glue_set| */ +@d set_extent(A) pack_extent(A) /* extent */ +@d set_shrink(A) mem[(A)+3+list_offset].sc @# + +@d align_node 16 /* represents an alignment */ +@d align_node_size 4 +@d align_extent(A) link(A+2) /* the extent of the alignment */ +@d align_m(A) type(A+2) /* either additional or exactly */ +@d align_v(A) subtype(A+2) /* true if vertical */ +@d align_preamble(A) info(A+3) /* the preamble */ +@d align_list(A) link(A+3) /* the unset rows/columns */ + +@d setpage_node 17 /* represents a page template */ +@d setpage_node_size 6 +@d setpage_name(A) link(A+1) +@d setpage_number(A) type(A+1) /* the \HINT/ number */ +@d setpage_id(A) subtype(A+1) /* the \TeX\ number */ +@d setpage_priority(A) info(A+2) +@d setpage_topskip(A) link(A+2) +@d setpage_depth(A) mem[A+3].sc /* maximum depth */ +@d setpage_height(A) info(A+4) /* extended dimension number */ +@d setpage_width(A) link(A+4) /* extended dimension number */ +@d setpage_list(A) info(A+5) /* the template itself */ +@d setpage_streams(A) link(A+5) /* list of stream definitions */ + +@d setstream_node 18 /* represents a stream definition */ +@d setstream_node_size 6 +@d setstream_number(A) type(A+1) +@d setstream_insertion(A) subtype(A+1) +@d setstream_mag(A) link(A+1) /* magnification factor */ +@d setstream_prefered(A) type(A+2) +@d setstream_next(A) subtype(A+2) +@d setstream_ratio(A) link(A+2) /* split ratio */ +@d setstream_max(A) info(A+3) /* extended dimension number */ +@d setstream_width(A) link(A+3) /* extended dimension number */ +@d setstream_topskip(A) info(A+4) +@d setstream_height(A) link(A+4) +@d setstream_before(A) info(A+5) +@d setstream_after(A) link(A+5) + +@d stream_node 19 /* represents a stream insertion point */ +@d stream_node_size 2 +@d stream_number(A) type(A+1) +@d stream_insertion(A) subtype(A+1) + +@d stream_after_node 20 /* never allocated */ +@d stream_before_node 21 /* never allocated */ + +@d xdimen_node 22 +@d xdimen_node_size 4 +@d xdimen_ref_count(A) link(A) +@d xdimen_width(A) mem[A+1].sc +@d xdimen_hfactor(A) mem[A+2].sc +@d xdimen_vfactor(A) mem[A+3].sc + +@d ignore_node 23 /* ignored used to attach extra information */ +@d ignore_node_size small_node_size /* same as |disc_node| */ +@d ignore_info(A) type(A+1) +@d ignore_list(A) link(A+1) + +@d label_node 24 /* represents a link to a another location */ +@d label_node_size 2 +@d label_has_name(A) type(A+1) /* 1 for a name , 0 for a number */ +@d label_where(A) subtype(A+1) /* 1 for top, 2 for bot, 3 for mid */ +@d label_ptr(A) link(A+1) /* for a name the token list or the number */ +@d label_ref(A) link(A+1) /*alternatively the label number */ + +@d start_link_node 25 /* represents a link to a another location */ +@d end_link_node 26 /* represents a link to a another location */ +@d link_node_size 2 /* second word like a |label_node| */ + +@d outline_node 27 /* represents an outline item */ +@d outline_node_size 4 /* second word like a |label_node| */ +@d outline_ptr(A) link(A+2) /* text to be displayed */ +@d outline_depth(A) mem[A+3].i /* depth of sub items */ + + +@ The sixteen possible \.{\\write} streams are represented by the |write_file| +array. The |j|th file is open if and only if |write_open[j]==true|. The last +two streams are special; |write_open[16]| represents a stream number +greater than 15, while |write_open[17]| represents a negative stream number, +and both of these variables are always |false|. + +@<Glob...@>= +static alpha_file @!write_file[16]; +static bool @!write_open[18]; + +@ @<Set init...@>= +for (k=0; k<=17; k++) write_open[k]=false; + +@ Extensions might introduce new command codes; but it's best to use +|extension| with a modifier, whenever possible, so that |main_control| +stays the same. + +@d immediate_code 4 /*command modifier for \.{\\immediate}*/ +@d set_language_code 5 /*command modifier for \.{\\setlanguage}*/ + +@<Put each...@>= +primitive("openout", extension, open_node);@/ +@!@:open\_out\_}{\.{\\openout} primitive@> +primitive("write", extension, write_node);write_loc=cur_val;@/ +@!@:write\_}{\.{\\write} primitive@> +primitive("closeout", extension, close_node);@/ +@!@:close\_out\_}{\.{\\closeout} primitive@> +primitive("special", extension, special_node);@/ +@!@:special\_}{\.{\\special} primitive@> +primitive("immediate", extension, immediate_code);@/ +@!@:immediate\_}{\.{\\immediate} primitive@> +primitive("setlanguage", extension, set_language_code);@/ +@!@:set\_language\_}{\.{\\setlanguage} primitive@> + +primitive("@@HINT", relax, 256); /*cf.\ |relax|*/ +@!@:@@HINT\_}{\.{\\@@HINT} primitive@> + +primitive("HINTdest", extension, label_node);@/ +@!@:HINTdest\_}{\.{\\HINTdest} primitive@> + +primitive("HINTstartlink", extension, start_link_node);@/ +@!@:startlink\_}{\.{\\HINTstartlink} primitive@> + +primitive("HINTendlink", extension, end_link_node);@/ +@!@:HINTendlink\_}{\.{\\HINTendlink} primitive@> + +primitive("HINToutline", extension, outline_node);@/ +@!@:HINToutline\_}{\.{\\HINToutline} primitive@> + +primitive("image", extension, image_node);@/ +@!@:image\_}{\.{\\image} primitive@> + +primitive("setpage", extension, setpage_node);@/ +@!@:setpage\_}{\.{\\setpage} primitive@> + +primitive("stream", extension, stream_node);@/ +@!@:stream\_}{\.{\\stream} primitive@> + +primitive("setstream", extension, setstream_node);@/ +@!@:setstream\_}{\.{\\setstream} primitive@> + +primitive("before", extension, stream_before_node);@/ +@!@:before\_}{\.{\\before} primitive@> + +primitive("after", extension, stream_after_node);@/ +@!@:after\_}{\.{\\after} primitive@> + + +@ The variable |write_loc| just introduced is used to provide an +appropriate error message in case of ``runaway'' write texts. + +@<Glob...@>= +static pointer @!write_loc; /*|eqtb| address of \.{\\write}*/ + +@ @<Cases of |print_cmd_chr|...@>= +case extension: switch (chr_code) { + case open_node: print_esc("openout");@+break; + case write_node: print_esc("write");@+break; + case close_node: print_esc("closeout");@+break; + case special_node: print_esc("special");@+break; + case par_node: print("parameter");@+break; + case graf_node: print("paragraf");@+break; + case disp_node: print("display");@+break; + case baseline_node: print("baselineskip");@+break; + case hpack_node: print("hpack");@+break; + case vpack_node: print("vpack");@+break; + case hset_node: print("hset");@+break; + case vset_node: print("vset");@+break; + case image_node: print("image");@+break; + case start_link_node: print("startlink");@+break; + case end_link_node: print("endlink");@+break; + case label_node: print("dest");@+break; + case outline_node: print("outline");@+break; + case align_node: print("align");@+break; + case setpage_node: print("setpage");@+break; + case setstream_node: print("setstream");@+break; + case stream_node: print("stream");@+break; + case xdimen_node: print("xdimen");@+break; + case ignore_node: print("ignore");@+break; + case immediate_code: print_esc("immediate");@+break; + case set_language_code: print_esc("setlanguage");@+break; + default:print("[unknown extension!]"); + } @+break; + +@ When an |extension| command occurs in |main_control|, in any mode, +the |do_extension| routine is called. + +@<Cases of |main_control| that are for extensions...@>= +any_mode(extension): do_extension(); + +@ @<Declare act...@>= +@t\4@>@<Declare procedures needed in |do_extension|@>@; +static void do_extension(void) +{@+int @!k; /*all-purpose integer*/ +pointer @!p; /*all-purpose pointer*/ +switch (cur_chr) { +case open_node: @<Implement \.{\\openout}@>@;@+break; +case write_node: @<Implement \.{\\write}@>@;@+break; +case close_node: @<Implement \.{\\closeout}@>@;@+break; +case special_node: @<Implement \.{\\special}@>@;@+break; +case par_node: +case graf_node: +case disp_node: +case baseline_node: +case hpack_node: +case vpack_node: +case hset_node: +case vset_node: +case align_node: @+break;@# +case image_node:@/ +{@+ pointer p; + scan_optional_equals(); + scan_file_name(); + p=new_image_node(cur_name,cur_area,cur_ext); + loop { + if (scan_keyword("width")) + {@+scan_normal_dimen;@+image_width(p)=cur_val;} + else if (scan_keyword("height")) + {@+scan_normal_dimen;image_height(p)=cur_val; } + else if (scan_keyword("plus")) + { scan_dimen(false, true, false); + image_stretch(p)=cur_val;image_stretch_order(p)=cur_order; + } + else if (scan_keyword("minus")) + { scan_dimen(false, true, false); + image_shrink(p)=cur_val;image_shrink_order(p)=cur_order; + } + else + break; + } + hget_image_information(p); + if (abs(mode)==vmode) + append_to_vlist(p); /* image nodes have height, width, and depth like boxes */ + else + tail_append(p); + break; +} +case start_link_node: + if (abs(mode) == vmode) + fatal_error("HiTeX startlink cannot be used in vertical mode"); + else + { new_whatsit(start_link_node,link_node_size); + scan_label(tail); + } + break; +case end_link_node: + if (abs(mode) == vmode) + fatal_error("HiTeX endlink cannot be used in vertical mode"); + else + new_whatsit(end_link_node,link_node_size); + break; +case label_node: + new_whatsit(label_node,label_node_size); + scan_destination(tail); + if (scan_keyword("top")) label_where(tail)=1; + else if (scan_keyword("bot")) label_where(tail)=2; + else label_where(tail)=3; + scan_spaces(); + break; +case outline_node: + new_whatsit(outline_node,outline_node_size); + scan_label(tail); + if (scan_keyword("depth")) + { scan_int(); + outline_depth(tail)= cur_val; + } + else outline_depth(tail)=0; + outline_ptr(tail)=null; + new_save_level(outline_group);scan_left_brace(); + push_nest();mode=-hmode;prev_depth=ignore_depth;space_factor=1000; + break; +case setpage_node: +{ uint8_t n;@+ + pointer t; + scan_eight_bit_int(); n=cur_val; + if (n==0) + { print_err("Illegal redefinition of page template 0"); print_int(n); error(); break;} + scan_optional_equals(); + scan_file_name(); /* this should be improved to use |scan_name|*/ + t=new_setpage_node(n,cur_name); + loop { + if (scan_keyword("priority")) + {@+scan_eight_bit_int();setpage_priority(t)=cur_val; } + else if (scan_keyword("width")) + {@+scan_normal_dimen; setpage_width(t)=new_xdimen(cur_val,cur_hfactor,cur_vfactor); } + else if (scan_keyword("height")) + {@+scan_normal_dimen; setpage_height(t)=new_xdimen(cur_val,cur_hfactor,cur_vfactor); } + else + break; + } + new_save_level(page_group);scan_left_brace();normal_paragraph(); + push_nest();mode=-vmode;prev_depth=ignore_depth; + break; +} +case stream_node: +{ uint8_t n; + scan_eight_bit_int(); n=cur_val; + new_whatsit(stream_node,stream_node_size); + stream_insertion(tail)=n; + stream_number(tail)=hget_stream_no(n); + break; +} +case setstream_node: +{ uint8_t n; + pointer t, s; + scan_eight_bit_int(); n=cur_val; + scan_optional_equals(); + t=link(setpage_head); + if (t==null) { print_err("\\setstream without \\setpage"); error(); break;} + s=new_setstream_node(n); + link(s)=setpage_streams(t); setpage_streams(t)=s; + loop { + if (scan_keyword("prefered")) + {@+scan_eight_bit_int(); + if (cur_val!=255) + setstream_prefered(s)=hget_stream_no(cur_val); } + else if (scan_keyword("next")) + {@+scan_eight_bit_int(); + if (cur_val!=255) + setstream_next(s)=hget_stream_no(cur_val); } + else if (scan_keyword("ratio")) + {@+scan_int();setstream_ratio(s)=cur_val; } + else + break; + } + new_save_level(stream_group);scan_left_brace();normal_paragraph(); + push_nest();mode=-vmode;prev_depth=ignore_depth; + break; +} +case stream_before_node: + scan_optional_equals(); + new_save_level(stream_before_group);scan_left_brace();normal_paragraph(); + push_nest();mode=-vmode;prev_depth=ignore_depth; + break; +case stream_after_node: + scan_optional_equals(); + new_save_level(stream_after_group);scan_left_brace();normal_paragraph(); + push_nest();mode=-vmode;prev_depth=ignore_depth; + break; +case xdimen_node: +case ignore_node: @+break; +case immediate_code: @<Implement \.{\\immediate}@>@;@+break; +case set_language_code: @<Implement \.{\\setlanguage}@>@;@+break; +default:confusion("ext1"); +@:this can't happen ext1}{\quad ext1@> +} +} + +@ @<Declare procedures needed in |do_extension|@>= +void scan_spaces(void) +{ @<Get the next non-blank non-call token@>; + back_input(); +} +void scan_destination(pointer p) +{@+if (scan_keyword("name")) + { label_has_name(p)=1; + scan_toks(false,true); label_ptr(p)=def_ref; + } + else if (scan_keyword("num")) + { label_has_name(p)=0; scan_int(); label_ptr(p)=cur_val; + } + else + { print_err("`name {...}' or `num 000' expected. Inserted `num 0'."); + label_has_name(p)=0; label_ptr(p)=0; + error(); + return; + } + scan_spaces(); +} +void scan_label(pointer p) +{ if (!scan_keyword("goto")) + print_err("keyword `goto' inserted"); + scan_destination(p); +} + +@ Here is a subroutine that creates a whatsit node having a given |subtype| +and a given number of words. It initializes only the first word of the whatsit, +and appends it to the current list. + +@<Declare procedures needed in |do_extension|@>= +static void new_whatsit(small_number @!s, small_number @!w) +{@+pointer p; /*the new node*/ +p=get_node(w);type(p)=whatsit_node;subtype(p)=s; +link(tail)=p;tail=p; +} + +@ The next subroutine uses |cur_chr| to decide what sort of whatsit is +involved, and also inserts a |write_stream| number. + +@<Declare procedures needed in |do_ext...@>= +static void new_write_whatsit(small_number @!w) +{@+new_whatsit(cur_chr, w); +if (w!=write_node_size) scan_four_bit_int(); +else{@+scan_int(); + if (cur_val < 0) cur_val=17; + else if (cur_val > 15) cur_val=16; + } +write_stream(tail)=cur_val; +} + +@ @<Implement \.{\\openout}@>= +{@+new_write_whatsit(open_node_size); +scan_optional_equals();scan_file_name();@/ +open_name(tail)=cur_name;open_area(tail)=s_no(cur_area);open_ext(tail)=s_no(cur_ext); +} + +@ When `\.{\\write 12\{...\}}' appears, we scan the token list `\.{\{...\}}' +without expanding its macros; the macros will be expanded later when this +token list is rescanned. + +@<Implement \.{\\write}@>= +{@+k=cur_cs;new_write_whatsit(write_node_size);@/ +cur_cs=k;p=scan_toks(false, false);write_tokens(tail)=def_ref; +} + +@ @<Implement \.{\\closeout}@>= +{@+new_write_whatsit(write_node_size);write_tokens(tail)=null; +} + +@ When `\.{\\special\{...\}}' appears, we expand the macros in the token +list as in \.{\\xdef} and \.{\\mark}. + +@<Implement \.{\\special}@>= +{@+new_whatsit(special_node, write_node_size);write_stream(tail)=null; +p=scan_toks(false, true);write_tokens(tail)=def_ref; +} + +@ Each new type of node that appears in our data structure must be capable +of being displayed, copied, destroyed, and so on. The routines that we +need for write-oriented whatsits are somewhat like those for mark nodes; +other extensions might, of course, involve more subtlety here. + +@<Basic printing...@>= +static void print_mark(int @!p); +static void print_label(pointer @!p) +{ print("goto "); + if (label_has_name(p)) { print("name "); print_mark(label_ptr(p));} + else { print("num "); print_int(label_ptr(p));} +} + +static void print_write_whatsit(char *@!s, pointer @!p) +{@+print_esc(s); +if (write_stream(p) < 16) print_int(write_stream(p)); +else if (write_stream(p)==16) print_char('*'); +@.*\relax@> +else print_char('-'); +} + +@ @<Display the whatsit...@>= +switch (subtype(p)) { +case open_node: {@+print_write_whatsit("openout", p); + print_char('=');printn_file_name(open_name(p), open_area(p), open_ext(p)); + } @+break; +case write_node: {@+print_write_whatsit("write", p); + print_mark(write_tokens(p)); + } @+break; +case close_node: print_write_whatsit("closeout", p);@+break; +case special_node: {@+print_esc("special"); + print_mark(write_tokens(p)); + } @+break; +case language_node: {@+print_esc("setlanguage"); + print_int(what_lang(p));print(" (hyphenmin "); + print_int(what_lhm(p));print_char(','); + print_int(what_rhm(p));print_char(')'); + } @+break; +case par_node: print_esc("parameter "); + print_int(par_type(p));print_char(',');print_int(par_number(p)); + print_char(':');print_int(par_value(p).i); + break; +case graf_node: print_esc("paragraf("); + print_int(graf_penalty(p)); + print_char(')'); + node_list_display(graf_params(p)); + node_list_display(graf_list(p)); + print_xdimen(graf_extent(p)); + break; +case disp_node: print_esc("display "); + node_list_display(display_eqno(p)); + if (display_left(p)) print("left "); else print("right "); + node_list_display(display_formula(p)); + node_list_display(display_params(p)); + break; +case baseline_node: print_esc("baselineskip "); + print_baseline_skip(baseline_node_no(p)); + break; +case hset_node: case vset_node: + print_char('\\'); + print_char(subtype(p)==hset_node?'h':'v'); + print("set("); + print_scaled(height(p)); print_char('+'); + print_scaled(depth(p)); print(")x"); print_scaled(width(p)); + if (shift_amount(p)!=0) + {@+print(", shifted ");print_scaled(shift_amount(p)); + } + if (set_stretch(p)!=0) + {@+print(", stretch ");print_glue(set_stretch(p),set_stretch_order(p),"pt"); + } + if (set_shrink(p)!=0) + {@+print(", shrink ");print_glue(set_shrink(p),set_shrink_order(p),"pt"); + } + print(", extent "); print_xdimen(set_extent(p)); + node_list_display(list_ptr(p)); /*recursive call*/ + break; +case hpack_node: case vpack_node: + print_char('\\'); + print_char(subtype(p)==hpack_node?'h':'v'); + print("pack("); + print(pack_m(p)==exactly?"exactly ":"additional "); + print_xdimen(pack_extent(p)); + if (subtype(p)==vpack_node && pack_limit(p)!=max_dimen) { print(", limit "); print_scaled(pack_limit(p)); } + print_char(')'); + node_list_display(list_ptr(p)); + break; +case image_node: + print_esc("image("); + print_char('(');print_scaled(image_height(p)); + print_char('+'); print_scaled(image_depth(p)); + print(")x"); print_scaled(image_width(p)); + if (image_stretch(p)!=0) { print(" plus ");print_glue(image_stretch(p), image_stretch_order(p),"pt"); } + if (image_shrink(p)!=0) { print(" minus ");print_glue(image_shrink(p), image_shrink_order(p), "pt"); } + print(", section ");print_int(image_no(p)); + if (image_name(p)!=0) {print(", "); printn(image_name(p));} + break; +case align_node: + print_esc("align("); + print(align_m(p)==exactly?"exactly ":"additional "); + print_xdimen(align_extent(p));print_char(')'); + node_list_display(align_preamble(p)); + print_char(':'); + node_list_display(align_list(p)); + break; +case setpage_node: + print_esc("setpage");print_int(setpage_number(p));print_char(' '); printn(setpage_name(p)); + print(" priority ");print_int(setpage_priority(p)); + print(" width ");print_xdimen(setpage_width(p)); + print(" height ");print_xdimen(setpage_height(p)); + print_ln();print_current_string();print(".\\topskip=");print_spec(setpage_topskip(p),0); + print_ln();print_current_string();print(".\\maxdepth=");print_scaled(setpage_depth(p)); + node_list_display(setpage_list(p)); + node_list_display(setpage_streams(p)); + break; +case setstream_node: + print_esc("setstream");print_int(setstream_insertion(p)); + print_char('(');print_int(setstream_number(p));print_char(')'); + if (setstream_prefered(p)!=255) { print(" prefered ");print_int(setstream_prefered(p)); } + if (setstream_ratio(p)>0) { print(" ratio ");print_int(setstream_ratio(p)); } + if (setstream_next(p)!=255) { print(" next ");print_int(setstream_next(p)); } + append_char('.'); + print_ln();print_current_string();print_esc("count");print_int(setstream_insertion(p));print_char('='); + print_int(setstream_mag(p)); + print_ln();print_current_string();print_esc("dimen");print_int(setstream_insertion(p));print_char('='); + print_xdimen(setstream_max(p)); + print_ln();print_current_string();print_esc("skip");print_int(setstream_insertion(p));print_char('='); + print_spec(setstream_height(p),0); + print_ln();print_current_string();print_esc("hsize=");print_xdimen(setstream_width(p)); + print_ln();print_current_string();print_esc("topskip=");print_spec(setstream_topskip(p),0); + if (setstream_before(p)!=null) { print_ln();print_current_string();print_esc("before");node_list_display(setstream_before(p));} + if (setstream_after(p)!=null) { print_ln();print_current_string();print_esc("after");node_list_display(setstream_after(p));} + flush_char; + break; +case ignore_node: + print_esc("ignore ");print_int(ignore_info(p));print_char(':'); + node_list_display(ignore_list(p)); + break; +case start_link_node: + print_esc("startlink "); + print_label(p); + break; +case end_link_node: + print_esc("endlink "); + break; +case label_node: + print_esc("dest "); + print_label(p); + if (label_where(p)==1) print("top"); + else if (label_where(p)==2) print("bot"); + else if (label_where(p)==3) print("mid"); + else print("undefined"); + break; +case outline_node: + print_esc("outline"); + print_label(p); + print(" depth "); print_int(outline_depth(p)); + if (outline_ptr(p)==null) print("{}"); else + { print_ln();print_current_string();node_list_display(outline_ptr(p));} + break; +case stream_node: + print_esc("stream");print_int(stream_insertion(p)); + print_char('(');print_int(stream_number(p));print_char(')'); + break; +case xdimen_node: + print_esc("xdimen ");print_xdimen(p); + break; +default: print("whatsit?"); +} + +@ @<Make a partial copy of the whatsit...@>= +switch (subtype(p)) { +case open_node: {@+r=get_node(open_node_size);words=open_node_size; + } @+break; +case write_node: case special_node: {@+r=get_node(write_node_size); + add_token_ref(write_tokens(p));words=write_node_size; + } @+break; +case close_node: case language_node: {@+r=get_node(small_node_size); + words=small_node_size; + } @+break; +case par_node: +{@+r=get_node(par_node_size); + if (par_type(p)==glue_type) add_glue_ref(par_value(p).i); + words=par_node_size; + } @+break; +case graf_node: +{@+r=get_node(graf_node_size); + add_xdimen_ref(graf_extent(p)); + graf_params(r)=copy_node_list(graf_params(p)); + graf_list(r)=copy_node_list(graf_list(p)); + words=graf_node_size-1; + } @+break; +case disp_node: +{@+r=get_node(disp_node_size); + display_left(r)=display_left(p); + display_no_bs(r)=display_no_bs(p); + display_eqno(r)=copy_node_list(display_eqno(p)); + display_formula(r)=copy_node_list(display_formula(p)); + display_params(r)=copy_node_list(display_params(p)); + words=disp_node_size-2; + } @+break; +case baseline_node: +{@+r=get_node(baseline_node_size); + words=baseline_node_size; + } @+break; +case hpack_node: case vpack_node: +{@+r=get_node(pack_node_size); + pack_m(r)=pack_m(p); + list_ptr(r)=copy_node_list(list_ptr(p)); + add_xdimen_ref(pack_extent(p)); + pack_limit(r)=pack_limit(p); + words=pack_node_size-3; + } @+break; +case hset_node: case vset_node: +{@+r=get_node(set_node_size); + mem[r+8]=mem[p+8];mem[r+7]=mem[p+7];mem[r+6]=mem[p+6];mem[r+5]=mem[p+5]; /*copy the last four words*/ + add_xdimen_ref(set_extent(p)); + list_ptr(r)=copy_node_list(list_ptr(p)); /*this affects |mem[r+5]|*/ + words=5; + } @+break; +case image_node: + r=get_node(image_node_size); + words=image_node_size; + break; +case align_node: + {@+r=get_node(align_node_size); + align_preamble(r)=copy_node_list(align_preamble(p)); + align_list(r)=copy_node_list(align_list(p)); + add_xdimen_ref(align_extent(p)); + words=align_node_size-1; + } @+break; +case setpage_node: + {@+r=get_node(setpage_node_size); + add_glue_ref(setpage_topskip(p)); + add_xdimen_ref(setpage_height(p)); + add_xdimen_ref(setpage_width(p)); + setpage_list(r)=copy_node_list(setpage_list(p)); + setpage_streams(r)=copy_node_list(setpage_streams(p)); + words=setpage_node_size-1; + } @+break; +case setstream_node: + {@+r=get_node(setstream_node_size); + add_xdimen_ref(setstream_max(p)); + add_xdimen_ref(setstream_width(p)); + add_glue_ref(setstream_topskip(p)); + add_glue_ref(setstream_height(p)); + setstream_before(r)=copy_node_list(setstream_before(p)); + setstream_after(r)=copy_node_list(setstream_after(p)); + words=setstream_node_size-1; + } @+break; +case ignore_node: + r=get_node(ignore_node_size); + ignore_info(r)=ignore_info(p); + ignore_list(r)=copy_node_list(ignore_list(p)); + words=ignore_node_size-1; + break; +case start_link_node: + r=get_node(link_node_size); + if (label_has_name(p)) add_token_ref(label_ptr(p)); + words=link_node_size; + break; +case end_link_node: + r=get_node(link_node_size); + words=link_node_size; + break; +case label_node: + r=get_node(label_node_size); + if (label_has_name(p)) add_token_ref(label_ptr(p)); + words=label_node_size; + break; +case outline_node: + r=get_node(outline_node_size); + if (label_has_name(p)) add_token_ref(label_ptr(p)); + outline_ptr(r)=copy_node_list(outline_ptr(p)); + words=outline_node_size-1; + break; +case stream_node: + r=get_node(stream_node_size); + words=stream_node_size; + break; +case xdimen_node: + r=get_node(xdimen_node_size); + words=xdimen_node_size; + break; +default:confusion("ext2"); +@:this can't happen ext2}{\quad ext2@> +} + +@ @<Wipe out the whatsit...@>= +{@+switch (subtype(p)) { +case open_node: free_node(p, open_node_size);@+break; +case write_node: case special_node: {@+delete_token_ref(write_tokens(p)); + free_node(p, write_node_size);goto done; + } +case close_node: case language_node: free_node(p, small_node_size);@+break; +case par_node: + if (par_type(p)==glue_type) fast_delete_glue_ref(par_value(p).i); + free_node(p, par_node_size);@+break; +case graf_node: + delete_xdimen_ref(graf_extent(p)); + flush_node_list(graf_params(p)); + flush_node_list(graf_list(p)); + free_node(p, graf_node_size);@+break; +case disp_node: + flush_node_list(display_eqno(p)); + flush_node_list(display_formula(p)); + flush_node_list(display_params(p)); + free_node(p, disp_node_size);@+break; +case baseline_node: + free_node(p, baseline_node_size);@+break; +case hpack_node: case vpack_node: + delete_xdimen_ref(pack_extent(p)); + flush_node_list(list_ptr(p)); + free_node(p, pack_node_size);@+break; +case hset_node: case vset_node: + delete_xdimen_ref(set_extent(p)); + flush_node_list(list_ptr(p)); + free_node(p, set_node_size);@+break; +case image_node: + free_node(p,image_node_size);@+break; +case align_node: + delete_xdimen_ref(align_extent(p)); + flush_node_list(align_preamble(p)); + flush_node_list(align_list(p)); + free_node(p, align_node_size);@+break; +case setpage_node: + delete_glue_ref(setpage_topskip(p)); + delete_xdimen_ref(setpage_height(p)); + delete_xdimen_ref(setpage_width(p)); + flush_node_list(setpage_list(p)); + flush_node_list(setpage_streams(p)); + free_node(p, setpage_node_size);@+break; +case setstream_node: + delete_xdimen_ref(setstream_max(p)); + delete_xdimen_ref(setstream_width(p)); + delete_glue_ref(setstream_topskip(p)); + delete_glue_ref(setstream_height(p)); + flush_node_list(setstream_before(p)); + flush_node_list(setstream_after(p)); + free_node(p,setstream_node_size); @+break; +case ignore_node: + flush_node_list(ignore_list(p)); + free_node(p,ignore_node_size); @+break; +case start_link_node: + if (label_has_name(p)) delete_token_ref(label_ptr(p)); + free_node(p,link_node_size);@+break; +case end_link_node: + free_node(p,link_node_size);@+break; +case label_node: + if (label_has_name(p)) delete_token_ref(label_ptr(p)); + free_node(p,label_node_size);@+break; +case outline_node: + if (label_has_name(p)) delete_token_ref(label_ptr(p)); + flush_node_list(outline_ptr(p)); + free_node(p,outline_node_size);@+break; +case stream_node: + free_node(p,stream_node_size); @+break; +case xdimen_node: + free_node(p,xdimen_node_size); +default:confusion("ext3"); +@:this can't happen ext3}{\quad ext3@> +} @/ +goto done; +} + +@ @<Incorporate a whatsit node into a vbox@>=do_nothing + +@ @<Incorporate a whatsit node into an hbox@>=do_nothing + +@ @<Let |d| be the width of the whatsit |p|@>=d=0 + +@ @d adv_past(A) @+if (subtype(A)==language_node) + {@+cur_lang=what_lang(A);l_hyf=what_lhm(A);r_hyf=what_rhm(A);@+} + +@<Advance \(p)past a whatsit node in the \(l)|line_break| loop@>=@+ +adv_past(cur_p) + +@ @<Advance \(p)past a whatsit node in the \(p)pre-hyphenation loop@>=@+ +adv_past(s) + +@ @<Prepare to move whatsit |p| to the current page, then |goto contribute|@>= +goto contribute + +@ @<Process whatsit |p| in |vert_break| loop, |goto not_found|@>= +goto not_found + +@ @<Output the whatsit node |p| in a vlist@>= +out_what(p) + +@ @<Output the whatsit node |p| in an hlist@>= +out_what(p) + +@ After all this preliminary shuffling, we come finally to the routines +that actually send out the requested data. Let's do \.{\\special} first +(it's easier). + +@<Declare procedures needed in |hlist_out|, |vlist_out|@>= +static void special_out(pointer @!p) +{@+int old_setting; /*holds print |selector|*/ +int @!k; /*index into |str_pool|*/ +synch_h;synch_v;@/ +old_setting=selector;selector=new_string; +show_token_list(link(write_tokens(p)), null, pool_size-pool_ptr); +selector=old_setting; +str_room(1); +if (cur_length < 256) + {@+dvi_out(xxx1);dvi_out(cur_length); + } +else{@+dvi_out(xxx4);dvi_four(cur_length); + } +for (k=str_start[str_ptr]; k<=pool_ptr-1; k++) dvi_out(so(str_pool[k])); +pool_ptr=str_start[str_ptr]; /*erase the string*/ +} + +@ To write a token list, we must run it through \TeX's scanner, expanding +macros and \.{\\the} and \.{\\number}, etc. This might cause runaways, +if a delimited macro parameter isn't matched, and runaways would be +extremely confusing since we are calling on \TeX's scanner in the middle +of a \.{\\shipout} command. Therefore we will put a dummy control sequence as +a ``stopper,'' right after the token list. This control sequence is +artificially defined to be \.{\\outer}. +@:end\_write\_}{\.{\\endwrite}@> + +@<Initialize table...@>= +text(end_write)=s_no("endwrite");eq_level(end_write)=level_one; +eq_type(end_write)=outer_call;equiv(end_write)=null; + +@ @<Declare procedures needed in |hlist_out|, |vlist_out|@>= +static void write_out(pointer @!p) +{@+int old_setting; /*holds print |selector|*/ +int @!old_mode; /*saved |mode|*/ +small_number @!j; /*write stream number*/ +pointer @!q, @!r; /*temporary variables for list manipulation*/ +@<Expand macros in the token list and make |link(def_ref)| point to the result@>; +old_setting=selector;j=write_stream(p); +if (write_open[j]) selector=j; +else{@+ /*write to the terminal if file isn't open*/ + if ((j==17)&&(selector==term_and_log)) selector=log_only; + print_nl(""); + } +token_show(def_ref);print_ln(); +flush_list(def_ref);selector=old_setting; +} + +@ The final line of this routine is slightly subtle; at least, the author +didn't think about it until getting burnt! There is a used-up token list +@^Knuth, Donald Ervin@> +on the stack, namely the one that contained |end_write_token|. (We +insert this artificial `\.{\\endwrite}' to prevent runaways, as explained +above.) If it were not removed, and if there were numerous writes on a +single page, the stack would overflow. + +@d end_write_token cs_token_flag+end_write + +@<Expand macros in the token list and...@>= +q=get_avail();info(q)=right_brace_token+'}';@/ +r=get_avail();link(q)=r;info(r)=end_write_token;ins_list(q);@/ +begin_token_list(write_tokens(p), write_text);@/ +q=get_avail();info(q)=left_brace_token+'{';ins_list(q); + /*now we're ready to scan + `\.\{$\langle\,$token list$\,\rangle$\.{\} \\endwrite}'*/ +old_mode=mode;mode=0; + /*disable \.{\\prevdepth}, \.{\\spacefactor}, \.{\\lastskip}, \.{\\prevgraf}*/ +cur_cs=write_loc;q=scan_toks(false, true); /*expand macros, etc.*/ +get_token();@+if (cur_tok!=end_write_token) + @<Recover from an unbalanced write command@>; +mode=old_mode; +end_token_list() /*conserve stack space*/ + +@ @<Recover from an unbalanced write command@>= +{@+print_err("Unbalanced write command"); +@.Unbalanced write...@> +help2("On this page there's a \\write with fewer real {'s than }'s.",@/ +"I can't handle that very well; good luck.");error(); +@/do@+{get_token(); +}@+ while (!(cur_tok==end_write_token)); +} + +@ The |out_what| procedure takes care of outputting whatsit nodes for +|vlist_out| and |hlist_out|\kern-.3pt. + +@<Declare procedures needed in |hlist_out|, |vlist_out|@>= +void out_what(pointer @!p) +{@+small_number j; /*write stream number*/ +if (subtype(p)==open_node||subtype(p)==write_node||subtype(p)==close_node) +@<Do some work that has been queued up for \.{\\write}@>@; +} + +@ We don't implement \.{\\write} inside of leaders. (The reason is that +the number of times a leader box appears might be different in different +implementations, due to machine-dependent rounding in the glue calculations.) +@^leaders@> + +@<Do some work that has been queued up...@>= +if (!doing_leaders) + {@+j=write_stream(p); + if (subtype(p)==write_node) write_out(p); + else{@+if (write_open[j]) a_close(&write_file[j]); + if (subtype(p)==close_node) write_open[j]=false; + else if (j < 16) + {@+cur_name=open_name(p); + set_cur_area_ext(open_area(p),open_ext(p)); + if (cur_ext[0]==0) cur_ext=".tex"; + pack_cur_name; + while (!a_open_out(&write_file[j])) + prompt_file_name("output file name",".tex"); + write_open[j]=true; + } + } + } + +@ The presence of `\.{\\immediate}' causes the |do_extension| procedure +to descend to one level of recursion. Nothing happens unless \.{\\immediate} +is followed by `\.{\\openout}', `\.{\\write}', or `\.{\\closeout}'. +@^recursion@> + +@<Implement \.{\\immediate}@>= +{@+get_x_token(); +if ((cur_cmd==extension)&&(cur_chr <= close_node)) + {@+p=tail;do_extension(); /*append a whatsit node*/ + out_what(tail); /*do the action immediately*/ + flush_node_list(tail);tail=p;link(p)=null; + } +else back_input(); +} + +@ The \.{\\language} extension is somewhat different. +We need a subroutine that comes into play when a character of +a non-|clang| language is being appended to the current paragraph. + +@<Declare action...@>= +static void fix_language(void) +{@+ASCII_code @!l; /*the new current language*/ +if (language <= 0) l=0; +else if (language > 255) l=0; +else l=language; +if (l!=clang) + {@+new_whatsit(language_node, small_node_size); + what_lang(tail)=l;clang=l;@/ + what_lhm(tail)=norm_min(left_hyphen_min); + what_rhm(tail)=norm_min(right_hyphen_min); + } +} + +@ @<Implement \.{\\setlanguage}@>= +if (abs(mode)!=hmode) report_illegal_case(); +else{@+new_whatsit(language_node, small_node_size); + scan_int(); + if (cur_val <= 0) clang=0; + else if (cur_val > 255) clang=0; + else clang=cur_val; + what_lang(tail)=clang; + what_lhm(tail)=norm_min(left_hyphen_min); + what_rhm(tail)=norm_min(right_hyphen_min); + } + +@ @<Finish the extensions@>= +for (k=0; k<=15; k++) if (write_open[k]) a_close(&write_file[k]) + +@* The extended features of \eTeX. +The program has two modes of operation: (1)~In \TeX\ compatibility mode +it fully deserves the name \TeX\ and there are neither extended features +nor additional primitive commands. There are, however, a few +modifications that would be legitimate in any implementation of \TeX\ +such as, e.g., preventing inadequate results of the glue to \.{DVI} +unit conversion during |ship_out|. (2)~In extended mode there are +additional primitive commands and the extended features of \eTeX\ are +available. + +The distinction between these two modes of operation initially takes +place when a `virgin' \.{eINITEX} starts without reading a format file. +Later on the values of all \eTeX\ state variables are inherited when +\.{eVIRTEX} (or \.{eINITEX}) reads a format file. + +The code below is designed to work for cases where `$|init|\ldots|tini|$' +is a run-time switch. + +@<Enable \eTeX, if requested@>= +#ifdef @!INIT +if (iniversion && (buffer[loc]=='*'||etexp)&&str_eq_str(format_ident," (INITEX)")) + {@+no_new_control_sequence=false; + @<Generate all \eTeX\ primitives@>@; + if (buffer[loc]=='*') incr(loc); + eTeX_mode=1; /*enter extended mode*/ + @<Initialize variables for \eTeX\ extended mode@>; + } +#endif +@;@/ +if (!no_new_control_sequence) /*just entered extended mode ?*/ + no_new_control_sequence=true;@+else + +@ The \eTeX\ features available in extended mode are grouped into two +categories: (1)~Some of them are permanently enabled and have no +semantic effect as long as none of the additional primitives are +executed. (2)~The remaining \eTeX\ features are optional and can be +individually enabled and disabled. For each optional feature there is +an \eTeX\ state variable named \.{\\...state}; the feature is enabled, +resp.\ disabled by assigning a positive, resp.\ non-positive value to +that integer. + +@d eTeX_state_base (int_base+eTeX_state_code) +@d eTeX_state(A) eqtb[eTeX_state_base+A].i /*an \eTeX\ state variable*/ +@# +@d eTeX_version_code eTeX_int /*code for \.{\\eTeXversion}*/ + +@<Generate all \eTeX...@>= +primitive("lastnodetype", last_item, last_node_type_code); +@!@:last\_node\_type\_}{\.{\\lastnodetype} primitive@> +primitive("eTeXversion", last_item, eTeX_version_code); +@!@:eTeX\_version\_}{\.{\\eTeXversion} primitive@> +primitive("eTeXrevision", convert, eTeX_revision_code);@/ +@!@:eTeX\_revision\_}{\.{\\eTeXrevision} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case last_node_type_code: print_esc("lastnodetype");@+break; +case eTeX_version_code: print_esc("eTeXversion");@+break; + +@ @<Cases for fetching an integer value@>= +case eTeX_version_code: cur_val=eTeX_version;@+break; + +@ @d eTeX_ex (eTeX_mode==1) /*is this extended mode?*/ + +@<Glob...@>= +static int @!eTeX_mode; /*identifies compatibility and extended mode*/ + +@ @<Initialize table entries...@>= +eTeX_mode=0; /*initially we are in compatibility mode*/ +@<Initialize variables for \eTeX\ compatibility mode@>@; + +@ @<Dump the \eTeX\ state@>= +dump_int(eTeX_mode); +for (j=0; j<=eTeX_states-1; j++) eTeX_state(j)=0; /*disable all enhancements*/ + +@ @<Undump the \eTeX\ state@>= +undump(0, 1, eTeX_mode); +if (eTeX_ex) + {@+@<Initialize variables for \eTeX\ extended mode@>; + } +else{@+@<Initialize variables for \eTeX\ compatibility mode@>; + } + +@ The |eTeX_enabled| function simply returns its first argument as +result. This argument is |true| if an optional \eTeX\ feature is +currently enabled; otherwise, if the argument is |false|, the function +gives an error message. + +@<Declare \eTeX\ procedures for use...@>= +static bool eTeX_enabled(bool @!b, quarterword @!j, halfword @!k) +{@+if (!b) + {@+print_err("Improper ");print_cmd_chr(j, k); + help1("Sorry, this optional e-TeX feature has been disabled.");error(); + } +return b; +} + +@ First we implement the additional \eTeX\ parameters in the table of +equivalents. + +@<Generate all \eTeX...@>= +primitive("everyeof", assign_toks, every_eof_loc); +@!@:every\_eof\_}{\.{\\everyeof} primitive@> +primitive("tracingassigns", assign_int, int_base+tracing_assigns_code);@/ +@!@:tracing\_assigns\_}{\.{\\tracingassigns} primitive@> +primitive("tracinggroups", assign_int, int_base+tracing_groups_code);@/ +@!@:tracing\_groups\_}{\.{\\tracinggroups} primitive@> +primitive("tracingifs", assign_int, int_base+tracing_ifs_code);@/ +@!@:tracing\_ifs\_}{\.{\\tracingifs} primitive@> +primitive("tracingscantokens", assign_int, int_base+tracing_scan_tokens_code);@/ +@!@:tracing\_scan\_tokens\_}{\.{\\tracingscantokens} primitive@> +primitive("tracingnesting", assign_int, int_base+tracing_nesting_code);@/ +@!@:tracing\_nesting\_}{\.{\\tracingnesting} primitive@> + +@ @d every_eof equiv(every_eof_loc) + +@<Cases of |assign_toks| for |print_cmd_chr|@>= +case every_eof_loc: print_esc("everyeof");@+break; + +@ @<Cases for |print_param|@>= +case tracing_assigns_code: print_esc("tracingassigns");@+break; +case tracing_groups_code: print_esc("tracinggroups");@+break; +case tracing_ifs_code: print_esc("tracingifs");@+break; +case tracing_scan_tokens_code: print_esc("tracingscantokens");@+break; +case tracing_nesting_code: print_esc("tracingnesting");@+break; + +@ In order to handle \.{\\everyeof} we need an array |eof_seen| of +boolean variables. + +@<Glob...@>= +static bool @!eof_seen0[max_in_open], *const @!eof_seen = @!eof_seen0-1; /*has eof been seen?*/ + +@ The |print_group| procedure prints the current level of grouping and +the name corresponding to |cur_group|. + +@<Declare \eTeX\ procedures for tr...@>= +static void print_group(bool @!e) +{@+ +switch (cur_group) { + case bottom_level: {@+print("bottom level");return; + } + case simple_group: case semi_simple_group: + {@+if (cur_group==semi_simple_group) print("semi "); + print("simple"); + } @+break; + case hbox_group: case adjusted_hbox_group: + {@+if (cur_group==adjusted_hbox_group) print("adjusted "); + print("hbox"); + } @+break; + case vbox_group: print("vbox");@+break; + case vtop_group: print("vtop");@+break; + case align_group: case no_align_group: + {@+if (cur_group==no_align_group) print("no "); + print("align"); + } @+break; + case output_group: print("output");@+break; + case disc_group: print("disc");@+break; + case insert_group: print("insert");@+break; + case vcenter_group: print("vcenter");@+break; + case math_group: case math_choice_group: case math_shift_group: case math_left_group: + {@+print("math"); + if (cur_group==math_choice_group) print(" choice"); + else if (cur_group==math_shift_group) print(" shift"); + else if (cur_group==math_left_group) print(" left"); + } + } /*there are no other cases*/ +print(" group (level ");print_int(qo(cur_level));print_char(')'); +if (saved(-1)!=0) + {@+if (e) print(" entered at line ");else print(" at line "); + print_int(saved(-1)); + } +} + +@ The |group_trace| procedure is called when a new level of grouping +begins (|e==false|) or ends (|e==true|) with |saved(-1)| containing the +line number. + +@<Declare \eTeX\ procedures for tr...@>= +#ifdef @!STAT +static void group_trace(bool @!e) +{@+begin_diagnostic();print_char('{'); +if (e) print("leaving ");else print("entering "); +print_group(e);print_char('}');end_diagnostic(false); +} +#endif + +@ The \.{\\currentgrouplevel} and \.{\\currentgrouptype} commands return +the current level of grouping and the type of the current group +respectively. + +@d current_group_level_code (eTeX_int+1) /*code for \.{\\currentgrouplevel}*/ +@d current_group_type_code (eTeX_int+2) /*code for \.{\\currentgrouptype}*/ + +@<Generate all \eTeX...@>= +primitive("currentgrouplevel", last_item, current_group_level_code); +@!@:current\_group\_level\_}{\.{\\currentgrouplevel} primitive@> +primitive("currentgrouptype", last_item, current_group_type_code); +@!@:current\_group\_type\_}{\.{\\currentgrouptype} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case current_group_level_code: print_esc("currentgrouplevel");@+break; +case current_group_type_code: print_esc("currentgrouptype");@+break; + +@ @<Cases for fetching an integer value@>= +case current_group_level_code: cur_val=cur_level-level_one;@+break; +case current_group_type_code: cur_val=cur_group;@+break; + +@ The \.{\\currentiflevel}, \.{\\currentiftype}, and +\.{\\currentifbranch} commands return the current level of conditionals +and the type and branch of the current conditional. + +@d current_if_level_code (eTeX_int+3) /*code for \.{\\currentiflevel}*/ +@d current_if_type_code (eTeX_int+4) /*code for \.{\\currentiftype}*/ +@d current_if_branch_code (eTeX_int+5) /*code for \.{\\currentifbranch}*/ + +@<Generate all \eTeX...@>= +primitive("currentiflevel", last_item, current_if_level_code); +@!@:current\_if\_level\_}{\.{\\currentiflevel} primitive@> +primitive("currentiftype", last_item, current_if_type_code); +@!@:current\_if\_type\_}{\.{\\currentiftype} primitive@> +primitive("currentifbranch", last_item, current_if_branch_code); +@!@:current\_if\_branch\_}{\.{\\currentifbranch} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case current_if_level_code: print_esc("currentiflevel");@+break; +case current_if_type_code: print_esc("currentiftype");@+break; +case current_if_branch_code: print_esc("currentifbranch");@+break; + +@ @<Cases for fetching an integer value@>= +case current_if_level_code: {@+q=cond_ptr;cur_val=0; + while (q!=null) + {@+incr(cur_val);q=link(q); + } + } @+break; +case current_if_type_code: if (cond_ptr==null) cur_val=0; + else if (cur_if < unless_code) cur_val=cur_if+1; + else cur_val=-(cur_if-unless_code+1);@+break; +case current_if_branch_code: + if ((if_limit==or_code)||(if_limit==else_code)) cur_val=1; + else if (if_limit==fi_code) cur_val=-1; + else cur_val=0;@+break; + +@ The \.{\\fontcharwd}, \.{\\fontcharht}, \.{\\fontchardp}, and +\.{\\fontcharic} commands return information about a character in a +font. + +@d font_char_wd_code eTeX_dim /*code for \.{\\fontcharwd}*/ +@d font_char_ht_code (eTeX_dim+1) /*code for \.{\\fontcharht}*/ +@d font_char_dp_code (eTeX_dim+2) /*code for \.{\\fontchardp}*/ +@d font_char_ic_code (eTeX_dim+3) /*code for \.{\\fontcharic}*/ + +@<Generate all \eTeX...@>= +primitive("fontcharwd", last_item, font_char_wd_code); +@!@:font\_char\_wd\_}{\.{\\fontcharwd} primitive@> +primitive("fontcharht", last_item, font_char_ht_code); +@!@:font\_char\_ht\_}{\.{\\fontcharht} primitive@> +primitive("fontchardp", last_item, font_char_dp_code); +@!@:font\_char\_dp\_}{\.{\\fontchardp} primitive@> +primitive("fontcharic", last_item, font_char_ic_code); +@!@:font\_char\_ic\_}{\.{\\fontcharic} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case font_char_wd_code: print_esc("fontcharwd");@+break; +case font_char_ht_code: print_esc("fontcharht");@+break; +case font_char_dp_code: print_esc("fontchardp");@+break; +case font_char_ic_code: print_esc("fontcharic");@+break; + +@ @<Cases for fetching a dimension value@>= +case font_char_wd_code: +case font_char_ht_code: +case font_char_dp_code: +case font_char_ic_code: {@+scan_font_ident();q=cur_val;scan_char_num(); + if ((font_bc[q] <= cur_val)&&(font_ec[q] >= cur_val)) + {@+i=char_info(q, qi(cur_val)); + switch (m) { + case font_char_wd_code: cur_val=char_width(q, i);@+break; + case font_char_ht_code: cur_val=char_height(q, height_depth(i));@+break; + case font_char_dp_code: cur_val=char_depth(q, height_depth(i));@+break; + case font_char_ic_code: cur_val=char_italic(q, i); + } /*there are no other cases*/ + } + else cur_val=0; + } @+break; + +@ The \.{\\parshapedimen}, \.{\\parshapeindent}, and \.{\\parshapelength} +commands return the indent and length parameters of the current +\.{\\parshape} specification. + +@d par_shape_length_code (eTeX_dim+4) /*code for \.{\\parshapelength}*/ +@d par_shape_indent_code (eTeX_dim+5) /*code for \.{\\parshapeindent}*/ +@d par_shape_dimen_code (eTeX_dim+6) /*code for \.{\\parshapedimen}*/ + +@<Generate all \eTeX...@>= +primitive("parshapelength", last_item, par_shape_length_code); +@!@:par\_shape\_length\_}{\.{\\parshapelength} primitive@> +primitive("parshapeindent", last_item, par_shape_indent_code); +@!@:par\_shape\_indent\_}{\.{\\parshapeindent} primitive@> +primitive("parshapedimen", last_item, par_shape_dimen_code); +@!@:par\_shape\_dimen\_}{\.{\\parshapedimen} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case par_shape_length_code: print_esc("parshapelength");@+break; +case par_shape_indent_code: print_esc("parshapeindent");@+break; +case par_shape_dimen_code: print_esc("parshapedimen");@+break; + +@ @<Cases for fetching a dimension value@>= +case par_shape_length_code: +case par_shape_indent_code: +case par_shape_dimen_code: {@+q=cur_chr-par_shape_length_code;scan_int(); + if ((par_shape_ptr==null)||(cur_val <= 0)) cur_val=0; + else{@+if (q==2) + {@+q=cur_val%2;cur_val=(cur_val+q)/2; + } + if (cur_val > info(par_shape_ptr)) cur_val=info(par_shape_ptr); + cur_val=mem[par_shape_ptr+2*cur_val-q].sc; + } + cur_val_level=dimen_val; + } @+break; + +@ The \.{\\showgroups} command displays all currently active grouping +levels. + +@d show_groups 4 /* \.{\\showgroups} */ + +@<Generate all \eTeX...@>= +primitive("showgroups", xray, show_groups); +@!@:show\_groups\_}{\.{\\showgroups} primitive@> + +@ @<Cases of |xray| for |print_cmd_chr|@>= +case show_groups: print_esc("showgroups");@+break; + +@ @<Cases for |show_whatever|@>= +case show_groups: {@+begin_diagnostic();show_save_groups(); + } @+break; + +@ @<Types...@>= +typedef int32_t save_pointer; /*index into |save_stack|*/ + +@ The modifications of \TeX\ required for the display produced by the +|show_save_groups| procedure were first discussed by Donald~E. Knuth in +{\sl TUGboat\/} {\bf 11}, 165--170 and 499--511, 1990. +@^Knuth, Donald Ervin@> + +In order to understand a group type we also have to know its mode. +Since unrestricted horizontal modes are not associated with grouping, +they are skipped when traversing the semantic nest. + +@<Declare \eTeX\ procedures for use...@>= +static void show_save_groups(void) +{@+ +int p; /*index into |nest|*/ +int @!m; /*mode*/ +save_pointer @!v; /*saved value of |save_ptr|*/ +quarterword @!l; /*saved value of |cur_level|*/ +group_code @!c; /*saved value of |cur_group|*/ +int @!a; /*to keep track of alignments*/ +int @!i; +quarterword @!j; +char *@!s; +p=nest_ptr;nest[p]=cur_list; /*put the top level into the array*/ +v=save_ptr;l=cur_level;c=cur_group; +save_ptr=cur_boundary;decr(cur_level);@/ +a=1; +print_nl("");print_ln(); +loop@+{@+print_nl("### ");print_group(true); + if (cur_group==bottom_level) goto done; + @/do@+{m=nest[p].mode_field; + if (p > 0) decr(p);else m=vmode; + }@+ while (!(m!=hmode)); + print(" ("); + switch (cur_group) { + case simple_group: {@+incr(p);goto found2; + } + case hbox_group: case adjusted_hbox_group: s="hbox";@+break; + case vbox_group: s="vbox";@+break; + case vtop_group: s="vtop";@+break; + case align_group: if (a==0) + {@+if (m==-vmode) s="halign";else s="valign"; + a=1;goto found1; + } + else{@+if (a==1) print("align entry");else print_esc("cr"); + if (p >= a) p=p-a; + a=0;goto found; + } @+break; + case no_align_group: + {@+incr(p);a=-1;print_esc("noalign");goto found2; + } + case output_group: + {@+print_esc("output");goto found; + } + case math_group: goto found2; + case disc_group: case math_choice_group: + {@+if (cur_group==disc_group) print_esc("discretionary"); + else print_esc("mathchoice"); + for (i=1; i<=3; i++) if (i <= saved(-2)) print("{}"); + goto found2; + } + case insert_group: + {@+if (saved(-2)==255) print_esc("vadjust"); + else{@+print_esc("insert");print_int(saved(-2)); + } + goto found2; + } + case vcenter_group: {@+s="vcenter";goto found1; + } + case semi_simple_group: {@+incr(p);print_esc("begingroup");goto found; + } + case math_shift_group: + {@+if (m==mmode) print_char('$'); + else if (nest[p].mode_field==mmode) + {@+print_cmd_chr(eq_no, saved(-2));goto found; + } + print_char('$');goto found; + } + case math_left_group: + {@+if (type(nest[p+1].eTeX_aux_field)==left_noad) print_esc("left"); + else print_esc("middle"); + goto found; + } + } /*there are no other cases*/ + @<Show the box context@>; + found1: print_esc(s);@<Show the box packaging info@>; + found2: print_char('{'); + found: print_char(')');decr(cur_level); + cur_group=save_level(save_ptr);save_ptr=save_index(save_ptr); + } +done: save_ptr=v;cur_level=l;cur_group=c; +} + +@ @<Show the box packaging info@>= +if (saved(-2)!=0) + {@+print_char(' '); + if (saved(-3)==exactly) print("to");else print("spread"); + print_scaled(saved(-2));print("pt"); + } + +@ @<Show the box context@>= +i=saved(-4); +if (i!=0) + if (i < box_flag) + {@+if (abs(nest[p].mode_field)==vmode) j=hmove;else j=vmove; + if (i > 0) print_cmd_chr(j, 0);else print_cmd_chr(j, 1); + print_scaled(abs(i));print("pt"); + } + else if (i < ship_out_flag) + {@+if (i >= global_box_flag) + {@+print_esc("global");i=i-(global_box_flag-box_flag); + } + print_esc("setbox");print_int(i-box_flag);print_char('='); + } + else print_cmd_chr(leader_ship, i-(leader_flag-a_leaders)) + +@ The |scan_general_text| procedure is much like |scan_toks(false, false)|, +but will be invoked via |expand|, i.e., recursively. +@^recursion@> + +@<Declare \eTeX\ procedures for sc...@>= +static void scan_general_text(void); + +@ The token list (balanced text) created by |scan_general_text| begins +at |link(temp_head)| and ends at |cur_val|. (If |cur_val==temp_head|, +the list is empty.) + +@<Declare \eTeX\ procedures for tok...@>= +static void scan_general_text(void) +{@+ +int s; /*to save |scanner_status|*/ +pointer @!w; /*to save |warning_index|*/ +pointer @!d; /*to save |def_ref|*/ +pointer @!p; /*tail of the token list being built*/ +pointer @!q; /*new node being added to the token list via |store_new_token|*/ +halfword @!unbalance; /*number of unmatched left braces*/ +s=scanner_status;w=warning_index;d=def_ref; +scanner_status=absorbing;warning_index=cur_cs; +def_ref=get_avail();token_ref_count(def_ref)=null;p=def_ref; +scan_left_brace(); /*remove the compulsory left brace*/ +unbalance=1; +loop@+{@+get_token(); + if (cur_tok < right_brace_limit) + if (cur_cmd < right_brace) incr(unbalance); + else{@+decr(unbalance); + if (unbalance==0) goto found; + } + store_new_token(cur_tok); + } +found: q=link(def_ref);free_avail(def_ref); /*discard reference count*/ +if (q==null) cur_val=temp_head;@+else cur_val=p; +link(temp_head)=q; +scanner_status=s;warning_index=w;def_ref=d; +} + +@ The \.{\\showtokens} command displays a token list. + +@d show_tokens 5 /* \.{\\showtokens} , must be odd! */ + +@<Generate all \eTeX...@>= +primitive("showtokens", xray, show_tokens); +@!@:show\_tokens\_}{\.{\\showtokens} primitive@> + +@ @<Cases of |xray| for |print_cmd_chr|@>= +case show_tokens: print_esc("showtokens");@+break; + +@ The \.{\\unexpanded} primitive prevents expansion of tokens much as +the result from \.{\\the} applied to a token variable. The +\.{\\detokenize} primitive converts a token list into a list of +character tokens much as if the token list were written to a file. We +use the fact that the command modifiers for \.{\\unexpanded} and +\.{\\detokenize} are odd whereas those for \.{\\the} and \.{\\showthe} +are even. + +@<Generate all \eTeX...@>= +primitive("unexpanded", the, 1);@/ +@!@:unexpanded\_}{\.{\\unexpanded} primitive@> +primitive("detokenize", the, show_tokens);@/ +@!@:detokenize\_}{\.{\\detokenize} primitive@> + +@ @<Cases of |the| for |print_cmd_chr|@>=; +else if (chr_code==1) print_esc("unexpanded"); +else print_esc("detokenize") + +@ @<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>= +if (odd(cur_chr)) + {@+c=cur_chr;scan_general_text(); + if (c==1) return cur_val; + else{@+old_setting=selector;selector=new_string;b=pool_ptr; + p=get_avail();link(p)=link(temp_head); + token_show(p);flush_list(p); + selector=old_setting;return str_toks(b); + } + + } + +@ The \.{\\showifs} command displays all currently active conditionals. + +@d show_ifs 6 /* \.{\\showifs} */ + +@<Generate all \eTeX...@>= +primitive("showifs", xray, show_ifs); +@!@:show\_ifs\_}{\.{\\showifs} primitive@> + +@ @<Cases of |xray| for |print_cmd_chr|@>= +case show_ifs: print_esc("showifs");@+break; + +@ @d print_if_line(A) if (A!=0) + {@+print(" entered on line ");print_int(A); + } + +@<Cases for |show_whatever|@>= +case show_ifs: {@+begin_diagnostic();print_nl("");print_ln(); + if (cond_ptr==null) + {@+print_nl("### ");print("no active conditionals"); + } + else{@+p=cond_ptr;n=0; + @/do@+{incr(n);p=link(p);@+}@+ while (!(p==null)); + p=cond_ptr;t=cur_if;l=if_line;m=if_limit; + @/do@+{print_nl("### level ");print_int(n);print(": "); + print_cmd_chr(if_test, t); + if (m==fi_code) print_esc("else"); + print_if_line(l); + decr(n);t=subtype(p);l=if_line_field(p);m=type(p);p=link(p); + }@+ while (!(p==null)); + } + } @+break; + +@ The \.{\\interactionmode} primitive allows to query and set the +interaction mode. + +@<Generate all \eTeX...@>= +primitive("interactionmode", set_page_int, 2); +@!@:interaction\_mode\_}{\.{\\interactionmode} primitive@> + +@ @<Cases of |set_page_int| for |print_cmd_chr|@>=; +else if (chr_code==2) print_esc("interactionmode") + +@ @<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>=; +else if (m==2) cur_val=interaction + +@ @<Declare \eTeX\ procedures for use...@>= +static void new_interaction(void); + +@ @<Cases for |alter_integer|@>=; +else if (c==2) + {@+if ((cur_val < batch_mode)||(cur_val > error_stop_mode)) + {@+print_err("Bad interaction mode"); +@.Bad interaction mode@> + help2("Modes are 0=batch, 1=nonstop, 2=scroll, and",@/ + "3=errorstop. Proceed, and I'll ignore this case."); + int_error(cur_val); + } + else{@+cur_chr=cur_val;new_interaction(); + } + } + +@ The |middle| feature of \eTeX\ allows one ore several \.{\\middle} +delimiters to appear between \.{\\left} and \.{\\right}. + +@<Generate all \eTeX...@>= +primitive("middle", left_right, middle_noad); +@!@:middle\_}{\.{\\middle} primitive@> + +@ @<Cases of |left_right| for |print_cmd_chr|@>=; +else if (chr_code==middle_noad) print_esc("middle") + +@ The |scan_tokens| feature of \eTeX\ defines the \.{\\scantokens} +primitive. + +@<Generate all \eTeX...@>= +primitive("scantokens", input, 2); +@!@:scan\_tokens\_}{\.{\\scantokens} primitive@> + +@ @<Cases of |input| for |print_cmd_chr|@>=; +else if (chr_code==2) print_esc("scantokens") + +@ @<Cases for |input|@>=; +else if (cur_chr==2) pseudo_start() + +@ The global variable |pseudo_files| is used to maintain a stack of +pseudo files. The |info| field of each pseudo file points to a linked +list of variable size nodes representing lines not yet processed: the +|info| field of the first word contains the size of this node, all the +following words contain ASCII codes. + +@<Glob...@>= +static pointer @!pseudo_files; /*stack of pseudo files*/ + +@ @<Set init...@>= +pseudo_files=null; + +@ The |pseudo_start| procedure initiates reading from a pseudo file. + +@<Declare \eTeX\ procedures for ex...@>= +static void pseudo_start(void); + +@ @<Declare \eTeX\ procedures for tok...@>= +static void pseudo_start(void) +{@+int old_setting; /*holds |selector| setting*/ +str_number @!s; /*string to be converted into a pseudo file*/ +pool_pointer @!l, @!m; /*indices into |str_pool|*/ +pointer @!p, @!q, @!r; /*for list construction*/ +four_quarters @!w; /*four ASCII codes*/ +int @!nl, @!sz; +scan_general_text(); +old_setting=selector;selector=new_string; +token_show(temp_head);selector=old_setting; +flush_list(link(temp_head)); +str_room(1);s=make_string(); +@<Convert string |s| into a new pseudo file@>; +flush_string; +@<Initiate input from new pseudo file@>; +} + +@ @<Convert string |s| into a new pseudo file@>= +str_pool[pool_ptr]=si(' ');l=str_start[s]; +nl=si(new_line_char); +p=get_avail();q=p; +while (l < pool_ptr) + {@+m=l; + while ((l < pool_ptr)&&(str_pool[l]!=nl)) incr(l); + sz=(l-m+7)/4; + if (sz==1) sz=2; + r=get_node(sz);link(q)=r;q=r;info(q)=hi(sz); + while (sz > 2) + {@+decr(sz);incr(r); + w.b0=qi(so(str_pool[m]));w.b1=qi(so(str_pool[m+1])); + w.b2=qi(so(str_pool[m+2]));w.b3=qi(so(str_pool[m+3])); + mem[r].qqqq=w;m=m+4; + } + w.b0=qi(' ');w.b1=qi(' ');w.b2=qi(' ');w.b3=qi(' '); + if (l > m) + {@+w.b0=qi(so(str_pool[m])); + if (l > m+1) + {@+w.b1=qi(so(str_pool[m+1])); + if (l > m+2) + {@+w.b2=qi(so(str_pool[m+2])); + if (l > m+3) w.b3=qi(so(str_pool[m+3])); + } + } + } + mem[r+1].qqqq=w; + if (str_pool[l]==nl) incr(l); + } +info(p)=link(p);link(p)=pseudo_files;pseudo_files=p + +@ @<Initiate input from new pseudo file@>= +begin_file_reading(); /*set up |cur_file| and new level of input*/ +line=0;limit=start;loc=limit+1; /*force line read*/ +if (tracing_scan_tokens > 0) + {@+if (term_offset > max_print_line-3) print_ln(); + else if ((term_offset > 0)||(file_offset > 0)) print_char(' '); + name=19;print("( ");incr(open_parens);update_terminal; + } +else name=18 + +@ Here we read a line from the current pseudo file into |buffer|. + +@<Declare \eTeX\ procedures for tr...@>= +static bool pseudo_input(void) /*inputs the next line or returns |false|*/ +{@+pointer p; /*current line from pseudo file*/ +int @!sz; /*size of node |p|*/ +four_quarters @!w; /*four ASCII codes*/ +int @!r; /*loop index*/ +last=first; /*cf.\ Matthew 19\thinspace:\thinspace30*/ +p=info(pseudo_files); +if (p==null) return false; +else{@+info(pseudo_files)=link(p);sz=ho(info(p)); + if (4*sz-3 >= buf_size-last) + @<Report overflow of the input buffer, and abort@>; + last=first; + for (r=p+1; r<=p+sz-1; r++) + {@+w=mem[r].qqqq; + buffer[last]=w.b0;buffer[last+1]=w.b1; + buffer[last+2]=w.b2;buffer[last+3]=w.b3; + last=last+4; + } + if (last >= max_buf_stack) max_buf_stack=last+1; + while ((last > first)&&(buffer[last-1]==' ')) decr(last); + free_node(p, sz); + return true; + } +} + +@ When we are done with a pseudo file we `close' it. + +@<Declare \eTeX\ procedures for tr...@>= +static void pseudo_close(void) /*close the top level pseudo file*/ +{@+pointer p, @!q; +p=link(pseudo_files);q=info(pseudo_files); +free_avail(pseudo_files);pseudo_files=p; +while (q!=null) + {@+p=q;q=link(p);free_node(p, ho(info(p))); + } +} + +@ @<Dump the \eTeX\ state@>= +while (pseudo_files!=null) pseudo_close(); /*flush pseudo files*/ + +@ @<Generate all \eTeX...@>= +primitive("readline", read_to_cs, 1);@/ +@!@:read\_line\_}{\.{\\readline} primitive@> + +@ @<Cases of |read| for |print_cmd_chr|@>=; +else print_esc("readline") + +@ @<Handle \.{\\readline} and |goto done|@>= +if (j==1) + {@+while (loc <= limit) /*current line not yet finished*/ + {@+cur_chr=buffer[loc];incr(loc); + if (cur_chr==' ') cur_tok=space_token; + @+else cur_tok=cur_chr+other_token; + store_new_token(cur_tok); + } + goto done; + } + +@ Here we define the additional conditionals of \eTeX\ as well as the +\.{\\unless} prefix. + +@d if_def_code 17 /* `\.{\\ifdefined}' */ +@d if_cs_code 18 /* `\.{\\ifcsname}' */ +@d if_font_char_code 19 /* `\.{\\iffontchar}' */ + +@<Generate all \eTeX...@>= +primitive("unless", expand_after, 1);@/ +@!@:unless\_}{\.{\\unless} primitive@> +primitive("ifdefined", if_test, if_def_code); +@!@:if\_defined\_}{\.{\\ifdefined} primitive@> +primitive("ifcsname", if_test, if_cs_code); +@!@:if\_cs\_name\_}{\.{\\ifcsname} primitive@> +primitive("iffontchar", if_test, if_font_char_code); +@!@:if\_font\_char\_}{\.{\\iffontchar} primitive@> + +@ @<Cases of |expandafter| for |print_cmd_chr|@>=; +else print_esc("unless") + +@ @<Cases of |if_test| for |print_cmd_chr|@>= +case if_def_code: print_esc("ifdefined");@+break; +case if_cs_code: print_esc("ifcsname");@+break; +case if_font_char_code: print_esc("iffontchar");@+break; + +@ The result of a boolean condition is reversed when the conditional is +preceded by \.{\\unless}. + +@<Negate a boolean conditional and |goto reswitch|@>= +{@+get_token(); +if ((cur_cmd==if_test)&&(cur_chr!=if_case_code)) + {@+cur_chr=cur_chr+unless_code;goto reswitch; + } +print_err("You can't use `");print_esc("unless");print("' before `"); +@.You can't use \\unless...@> +print_cmd_chr(cur_cmd, cur_chr);print_char('\''); +help1("Continue, and I'll forget that it ever happened."); +back_error(); +} + +@ The conditional \.{\\ifdefined} tests if a control sequence is +defined. + +We need to reset |scanner_status|, since \.{\\outer} control sequences +are allowed, but we might be scanning a macro definition or preamble. + +@<Cases for |conditional|@>= +case if_def_code: {@+save_scanner_status=scanner_status; + scanner_status=normal; + get_next();b=(cur_cmd!=undefined_cs); + scanner_status=save_scanner_status; + } @+break; + +@ The conditional \.{\\ifcsname} is equivalent to \.{\{\\expandafter} +\.{\}\\expandafter} \.{\\ifdefined} \.{\\csname}, except that no new +control sequence will be entered into the hash table (once all tokens +preceding the mandatory \.{\\endcsname} have been expanded). + +@<Cases for |conditional|@>= +case if_cs_code: {@+n=get_avail();p=n; /*head of the list of characters*/ + @/do@+{get_x_token(); + if (cur_cs==0) store_new_token(cur_tok); + }@+ while (!(cur_cs!=0)); + if (cur_cmd!=end_cs_name) @<Complain about missing \.{\\endcsname}@>; + @<Look up the characters of list |n| in the hash table, and set |cur_cs|@>; + flush_list(n); + b=(eq_type(cur_cs)!=undefined_cs); + } @+break; + +@ @<Look up the characters of list |n| in the hash table...@>= +m=first;p=link(n); +while (p!=null) + {@+if (m >= max_buf_stack) + {@+max_buf_stack=m+1; + if (max_buf_stack==buf_size) + overflow("buffer size", buf_size); +@:TeX capacity exceeded buffer size}{\quad buffer size@> + } + buffer[m]=info(p)%0400;incr(m);p=link(p); + } +if (m==first) cur_cs=null_cs; /*the list is empty*/ +else if (m > first+1) + cur_cs=id_lookup(first, m-first); /*|no_new_control_sequence| is |true|*/ +else cur_cs=single_base+buffer[first] /*the list has length one*/ + +@ The conditional \.{\\iffontchar} tests the existence of a character in +a font. + +@<Cases for |conditional|@>= +case if_font_char_code: {@+scan_font_ident();n=cur_val;scan_char_num(); + if ((font_bc[n] <= cur_val)&&(font_ec[n] >= cur_val)) + b=char_exists(char_info(n, qi(cur_val))); + else b=false; + } @+break; + +@ The |protected| feature of \eTeX\ defines the \.{\\protected} prefix +command for macro definitions. Such macros are protected against +expansions when lists of expanded tokens are built, e.g., for \.{\\edef} +or during \.{\\write}. + +@<Generate all \eTeX...@>= +primitive("protected", prefix, 8); +@!@:protected\_}{\.{\\protected} primitive@> + +@ @<Cases of |prefix| for |print_cmd_chr|@>=; +else if (chr_code==8) print_esc("protected") + +@ The |get_x_or_protected| procedure is like |get_x_token| except that +protected macros are not expanded. + +@<Declare \eTeX\ procedures for sc...@>= +static void get_x_or_protected(void) /*sets |cur_cmd|, |cur_chr|, |cur_tok|, + and expands non-protected macros*/ +{@+ +loop@+{@+get_token(); + if (cur_cmd <= max_command) return; + if ((cur_cmd >= call)&&(cur_cmd < end_template)) + if (info(link(cur_chr))==protected_token) return; + expand(); + } +} + +@ A group entered (or a conditional started) in one file may end in a +different file. Such slight anomalies, although perfectly legitimate, +may cause errors that are difficult to locate. In order to be able to +give a warning message when such anomalies occur, \eTeX\ uses the +|grp_stack| and |if_stack| arrays to record the initial |cur_boundary| +and |cond_ptr| values for each input file. + +@<Glob...@>= +static save_pointer @!grp_stack[max_in_open+1]; /*initial |cur_boundary|*/ +static pointer @!if_stack[max_in_open+1]; /*initial |cond_ptr|*/ + +@ When a group ends that was apparently entered in a different input +file, the |group_warning| procedure is invoked in order to update the +|grp_stack|. If moreover \.{\\tracingnesting} is positive we want to +give a warning message. The situation is, however, somewhat complicated +by two facts: (1)~There may be |grp_stack| elements without a +corresponding \.{\\input} file or \.{\\scantokens} pseudo file (e.g., +error insertions from the terminal); and (2)~the relevant information is +recorded in the |name_field| of the |input_stack| only loosely +synchronized with the |in_open| variable indexing |grp_stack|. + +@<Declare \eTeX\ procedures for tr...@>= +static void group_warning(void) +{@+int i; /*index into |grp_stack|*/ +bool @!w; /*do we need a warning?*/ +base_ptr=input_ptr;input_stack[base_ptr]=cur_input; + /*store current state*/ +i=in_open;w=false; +while ((grp_stack[i]==cur_boundary)&&(i > 0)) + {@+@<Set variable |w| to indicate if this case should be reported@>; + grp_stack[i]=save_index(save_ptr);decr(i); + } +if (w) + {@+print_nl("Warning: end of ");print_group(true); +@.Warning: end of...@> + print(" of a different file");print_ln(); + if (tracing_nesting > 1) show_context(); + if (history==spotless) history=warning_issued; + } +} + +@ This code scans the input stack in order to determine the type of the +current input file. + +@<Set variable |w| to...@>= +if (tracing_nesting > 0) + {@+while ((input_stack[base_ptr].state_field==token_list)||@| + (input_stack[base_ptr].index_field > i)) decr(base_ptr); + if (input_stack[base_ptr].name_field > 17) w=true; + } + +@ When a conditional ends that was apparently started in a different +input file, the |if_warning| procedure is invoked in order to update the +|if_stack|. If moreover \.{\\tracingnesting} is positive we want to +give a warning message (with the same complications as above). + +@<Declare \eTeX\ procedures for tr...@>= +static void if_warning(void) +{@+int i; /*index into |if_stack|*/ +bool @!w; /*do we need a warning?*/ +base_ptr=input_ptr;input_stack[base_ptr]=cur_input; + /*store current state*/ +i=in_open;w=false; +while (if_stack[i]==cond_ptr) + {@+@<Set variable |w| to...@>; + if_stack[i]=link(cond_ptr);decr(i); + } +if (w) + {@+print_nl("Warning: end of ");print_cmd_chr(if_test, cur_if); +@.Warning: end of...@> + print_if_line(if_line);print(" of a different file");print_ln(); + if (tracing_nesting > 1) show_context(); + if (history==spotless) history=warning_issued; + } +} + +@ Conversely, the |file_warning| procedure is invoked when a file ends +and some groups entered or conditionals started while reading from that +file are still incomplete. + +@<Declare \eTeX\ procedures for tr...@>= +static void file_warning(void) +{@+pointer p; /*saved value of |save_ptr| or |cond_ptr|*/ +quarterword @!l; /*saved value of |cur_level| or |if_limit|*/ +quarterword @!c; /*saved value of |cur_group| or |cur_if|*/ +int @!i; /*saved value of |if_line|*/ +p=save_ptr;l=cur_level;c=cur_group;save_ptr=cur_boundary; +while (grp_stack[in_open]!=save_ptr) + {@+decr(cur_level); + print_nl("Warning: end of file when "); +@.Warning: end of file when...@> + print_group(true);print(" is incomplete");@/ + cur_group=save_level(save_ptr);save_ptr=save_index(save_ptr); + } +save_ptr=p;cur_level=l;cur_group=c; /*restore old values*/ +p=cond_ptr;l=if_limit;c=cur_if;i=if_line; +while (if_stack[in_open]!=cond_ptr) + {@+print_nl("Warning: end of file when "); +@.Warning: end of file when...@> + print_cmd_chr(if_test, cur_if); + if (if_limit==fi_code) print_esc("else"); + print_if_line(if_line);print(" is incomplete");@/ + if_line=if_line_field(cond_ptr);cur_if=subtype(cond_ptr); + if_limit=type(cond_ptr);cond_ptr=link(cond_ptr); + } +cond_ptr=p;if_limit=l;cur_if=c;if_line=i; /*restore old values*/ +print_ln(); +if (tracing_nesting > 1) show_context(); +if (history==spotless) history=warning_issued; +} + +@ Here are the additional \eTeX\ primitives for expressions. + +@<Generate all \eTeX...@>= +primitive("numexpr", last_item, eTeX_expr-int_val+int_val); +@!@:num\_expr\_}{\.{\\numexpr} primitive@> +primitive("dimexpr", last_item, eTeX_expr-int_val+dimen_val); +@!@:dim\_expr\_}{\.{\\dimexpr} primitive@> +primitive("glueexpr", last_item, eTeX_expr-int_val+glue_val); +@!@:glue\_expr\_}{\.{\\glueexpr} primitive@> +primitive("muexpr", last_item, eTeX_expr-int_val+mu_val); +@!@:mu\_expr\_}{\.{\\muexpr} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case eTeX_expr-int_val+int_val: print_esc("numexpr");@+break; +case eTeX_expr-int_val+dimen_val: print_esc("dimexpr");@+break; +case eTeX_expr-int_val+glue_val: print_esc("glueexpr");@+break; +case eTeX_expr-int_val+mu_val: print_esc("muexpr");@+break; + +@ This code for reducing |cur_val_level| and\slash or negating the +result is similar to the one for all the other cases of +|scan_something_internal|, with the difference that |scan_expr| has +already increased the reference count of a glue specification. + +@<Process an expression and |return|@>= +{@+if (m < eTeX_mu) + {@+switch (m) { + @/@<Cases for fetching a glue value@>@/ + } /*there are no other cases*/ + cur_val_level=glue_val; + } +else if (m < eTeX_expr) + {@+switch (m) { + @/@<Cases for fetching a mu value@>@/ + } /*there are no other cases*/ + cur_val_level=mu_val; + } +else{@+cur_val_level=m-eTeX_expr+int_val;scan_expr(); + } +while (cur_val_level > level) + {@+if (cur_val_level==glue_val) + {@+m=cur_val;cur_val=width(m);delete_glue_ref(m); + } + else if (cur_val_level==mu_val) mu_error(); + decr(cur_val_level); + } +if (negative) + if (cur_val_level >= glue_val) + {@+m=cur_val;cur_val=new_spec(m);delete_glue_ref(m); + @<Negate all three glue components of |cur_val|@>; + } + else negate(cur_val); +return; +} + +@ @<Declare \eTeX\ procedures for sc...@>= +static void scan_expr(void); + +@ The |scan_expr| procedure scans and evaluates an expression. + +@<Declare procedures needed for expressions@>= +@t\4@>@<Declare subprocedures for |scan_expr|@>@; +static void scan_expr(void) /*scans and evaluates an expression*/ +{@+ +bool a, @!b; /*saved values of |arith_error|*/ +small_number @!l; /*type of expression*/ +small_number @!r; /*state of expression so far*/ +small_number @!s; /*state of term so far*/ +small_number @!o; /*next operation or type of next factor*/ +int @!e; /*expression so far*/ +int @!t; /*term so far*/ +int @!f; /*current factor*/ +int @!n; /*numerator of combined multiplication and division*/ +pointer @!p; /*top of expression stack*/ +pointer @!q; /*for stack manipulations*/ +l=cur_val_level;a=arith_error;b=false;p=null; +@<Scan and evaluate an expression |e| of type |l|@>; +if (b) + {@+print_err("Arithmetic overflow"); +@.Arithmetic overflow@> + help2("I can't evaluate this expression,",@/ + "since the result is out of range."); + error(); + if (l >= glue_val) + {@+delete_glue_ref(e);e=zero_glue;add_glue_ref(e); + } + else e=0; + } +arith_error=a;cur_val=e;cur_val_level=l; +} + +@ Evaluating an expression is a recursive process: When the left +parenthesis of a subexpression is scanned we descend to the next level +of recursion; the previous level is resumed with the matching right +parenthesis. + +@d expr_none 0 /*\.( seen, or \.( $\langle\it expr\rangle$ \.) seen*/ +@d expr_add 1 /*\.( $\langle\it expr\rangle$ \.+ seen*/ +@d expr_sub 2 /*\.( $\langle\it expr\rangle$ \.- seen*/ +@d expr_mult 3 /*$\langle\it term\rangle$ \.* seen*/ +@d expr_div 4 /*$\langle\it term\rangle$ \./ seen*/ +@d expr_scale 5 /*$\langle\it term\rangle$ \.* + $\langle\it factor\rangle$ \./ seen*/ + +@<Scan and eval...@>= +restart: r=expr_none;e=0;s=expr_none;t=0;n=0; +resume: if (s==expr_none) o=l;@+else o=int_val; +@<Scan a factor |f| of type |o| or start a subexpression@>; +found: @<Scan the next operator and set |o|@>; +arith_error=b; +@<Make sure that |f| is in the proper range@>; +switch (s) {@<Cases for evaluation of the current term@>@; +} /*there are no other cases*/ +if (o > expr_sub) s=o;@+else@<Evaluate the current expression@>; +b=arith_error; +if (o!=expr_none) goto resume; +if (p!=null) @<Pop the expression stack and |goto found|@>@; + +@ @<Scan the next op...@>= +@<Get the next non-blank non-call token@>; +if (cur_tok==other_token+'+') o=expr_add; +else if (cur_tok==other_token+'-') o=expr_sub; +else if (cur_tok==other_token+'*') o=expr_mult; +else if (cur_tok==other_token+'/') o=expr_div; +else{@+o=expr_none; + if (p==null) + {@+if (cur_cmd!=relax) back_input(); + } + else if (cur_tok!=other_token+')') + {@+print_err("Missing ) inserted for expression"); +@.Missing ) inserted@> + help1("I was expecting to see `+', `-', `*', `/', or `)'. Didn't."); + back_error(); + } + } + +@ @<Scan a factor...@>= +@<Get the next non-blank non-call token@>; +if (cur_tok==other_token+'(') + @<Push the expression stack and |goto restart|@>; +back_input(); +if (o==int_val) scan_int(); +else if (o==dimen_val) scan_normal_dimen; +else if (o==glue_val) scan_normal_glue(); +else scan_mu_glue(); +f=cur_val + +@ @<Declare \eTeX\ procedures for sc...@>= +static void scan_normal_glue(void);@/ +static void scan_mu_glue(void); + +@ Here we declare two trivial procedures in order to avoid mutually +recursive procedures with parameters. + +@<Declare procedures needed for expressions@>= +static void scan_normal_glue(void) +{@+scan_glue(glue_val); +} +@# +static void scan_mu_glue(void) +{@+scan_glue(mu_val); +} + +@ Parenthesized subexpressions can be inside expressions, and this +nesting has a stack. Seven local variables represent the top of the +expression stack: |p| points to pushed-down entries, if any; |l| +specifies the type of expression currently beeing evaluated; |e| is the +expression so far and |r| is the state of its evaluation; |t| is the +term so far and |s| is the state of its evaluation; finally |n| is the +numerator for a combined multiplication and division, if any. + +@d expr_node_size 4 /*number of words in stack entry for subexpressions*/ +@d expr_e_field(A) mem[A+1].i /*saved expression so far*/ +@d expr_t_field(A) mem[A+2].i /*saved term so far*/ +@d expr_n_field(A) mem[A+3].i /*saved numerator*/ + +@<Push the expression...@>= +{@+q=get_node(expr_node_size);link(q)=p;type(q)=l; +subtype(q)=4*s+r; +expr_e_field(q)=e;expr_t_field(q)=t;expr_n_field(q)=n; +p=q;l=o;goto restart; +} + +@ @<Pop the expression...@>= +{@+f=e;q=p; +e=expr_e_field(q);t=expr_t_field(q);n=expr_n_field(q); +s=subtype(q)/4;r=subtype(q)%4; +l=type(q);p=link(q);free_node(q, expr_node_size); +goto found; +} + +@ We want to make sure that each term and (intermediate) result is in +the proper range. Integer values must not exceed |infinity| +($2^{31}-1$) in absolute value, dimensions must not exceed |max_dimen| +($2^{30}-1$). We avoid the absolute value of an integer, because this +might fail for the value $-2^{31}$ using 32-bit arithmetic. + +@d num_error(A) /*clear a number or dimension and set |arith_error|*/ + {@+arith_error=true;A=0; + } +@d glue_error(A) /*clear a glue spec and set |arith_error|*/ + {@+arith_error=true;delete_glue_ref(A);A=new_spec(zero_glue); + } + +@<Make sure that |f|...@>= +if ((l==int_val)||(s > expr_sub)) + {@+if ((f > infinity)||(f < -infinity)) num_error(f); + } +else if (l==dimen_val) + {@+if (abs(f) > max_dimen) num_error(f); + } +else{@+if ((abs(width(f)) > max_dimen)||@| + (abs(stretch(f)) > max_dimen)||@| + (abs(shrink(f)) > max_dimen)) glue_error(f); + } + +@ Applying the factor |f| to the partial term |t| (with the operator +|s|) is delayed until the next operator |o| has been scanned. Here we +handle the first factor of a partial term. A glue spec has to be copied +unless the next operator is a right parenthesis; this allows us later on +to simply modify the glue components. + +@d normalize_glue(A) + if (stretch(A)==0) stretch_order(A)=normal; + if (shrink(A)==0) shrink_order(A)=normal + +@<Cases for evaluation of the current term@>= +case expr_none: if ((l >= glue_val)&&(o!=expr_none)) + {@+t=new_spec(f);delete_glue_ref(f);normalize_glue(t); + } + else t=f;@+break; + +@ When a term |t| has been completed it is copied to, added to, or +subtracted from the expression |e|. + +@d expr_add_sub(A, B, C) add_or_sub(A, B, C, r==expr_sub) +@d expr_a(A, B) expr_add_sub(A, B, max_dimen) + +@<Evaluate the current expression@>= +{@+s=expr_none; +if (r==expr_none) e=t; +else if (l==int_val) e=expr_add_sub(e, t, infinity); +else if (l==dimen_val) e=expr_a(e, t); +else@<Compute the sum or difference of two glue specs@>; +r=o; +} + +@ The function |add_or_sub(x, y, max_answer, negative)| computes the sum +(for |negative==false|) or difference (for |negative==true|) of |x| and +|y|, provided the absolute value of the result does not exceed +|max_answer|. + +@<Declare subprocedures for |scan_expr|@>= +static int add_or_sub(int @!x, int @!y, int @!max_answer, bool @!negative) +{@+int a; /*the answer*/ +if (negative) negate(y); +if (x >= 0) + if (y <= max_answer-x) a=x+y;@+else num_error(a)@; +else if (y >= -max_answer-x) a=x+y;@+else num_error(a); +return a; +} + +@ We know that |stretch_order(e) > normal| implies |stretch(e)!=0| and +|shrink_order(e) > normal| implies |shrink(e)!=0|. + +@<Compute the sum or diff...@>= +{@+width(e)=expr_a(width(e), width(t)); +if (stretch_order(e)==stretch_order(t)) + stretch(e)=expr_a(stretch(e), stretch(t)); +else if ((stretch_order(e) < stretch_order(t))&&(stretch(t)!=0)) + {@+stretch(e)=stretch(t);stretch_order(e)=stretch_order(t); + } +if (shrink_order(e)==shrink_order(t)) + shrink(e)=expr_a(shrink(e), shrink(t)); +else if ((shrink_order(e) < shrink_order(t))&&(shrink(t)!=0)) + {@+shrink(e)=shrink(t);shrink_order(e)=shrink_order(t); + } +delete_glue_ref(t);normalize_glue(e); +} + +@ If a multiplication is followed by a division, the two operations are +combined into a `scaling' operation. Otherwise the term |t| is +multiplied by the factor |f|. + +@d expr_m(A) A=nx_plus_y(A, f, 0) + +@<Cases for evaluation of the current term@>= +case expr_mult: if (o==expr_div) + {@+n=f;o=expr_scale; + } + else if (l==int_val) t=mult_integers(t, f); + else if (l==dimen_val) expr_m(t); + else{@+expr_m(width(t));expr_m(stretch(t));expr_m(shrink(t)); + } @+break; + +@ Here we divide the term |t| by the factor |f|. + +@d expr_d(A) A=quotient(A, f) + +@<Cases for evaluation of the current term@>= +case expr_div: if (l < glue_val) expr_d(t); + else{@+expr_d(width(t));expr_d(stretch(t));expr_d(shrink(t)); + } @+break; + +@ The function |quotient(n, d)| computes the rounded quotient +$q=\lfloor n/d+{1\over2}\rfloor$, when $n$ and $d$ are positive. + +@<Declare subprocedures for |scan_expr|@>= +static int quotient(int @!n, int @!d) +{@+bool negative; /*should the answer be negated?*/ +int @!a; /*the answer*/ +if (d==0) num_error(a)@; +else{@+if (d > 0) negative=false; + else{@+negate(d);negative=true; + } + if (n < 0) + {@+negate(n);negative=!negative; + } + a=n/d;n=n-a*d;d=n-d; /*avoid certain compiler optimizations!*/ + if (d+n >= 0) incr(a); + if (negative) negate(a); + } +return a; +} + +@ Here the term |t| is multiplied by the quotient $n/f$. + +@d expr_s(A) A=fract(A, n, f, max_dimen) + +@<Cases for evaluation of the current term@>= +case expr_scale: if (l==int_val) t=fract(t, n, f, infinity); + else if (l==dimen_val) expr_s(t); + else{@+expr_s(width(t));expr_s(stretch(t));expr_s(shrink(t)); + } + +@ Finally, the function |fract(x, n, d, max_answer)| computes the integer +$q=\lfloor xn/d+{1\over2}\rfloor$, when $x$, $n$, and $d$ are positive +and the result does not exceed |max_answer|. We can't use floating +point arithmetic since the routine must produce identical results in all +cases; and it would be too dangerous to multiply by~|n| and then divide +by~|d|, in separate operations, since overflow might well occur. Hence +this subroutine simulates double precision arithmetic, somewhat +analogous to \MF's |make_fraction| and |take_fraction| routines. + +@<Declare subprocedures for |scan_expr|@>= +static int fract(int @!x, int @!n, int @!d, int @!max_answer) +{@+ +bool negative; /*should the answer be negated?*/ +int @!a; /*the answer*/ +int @!f; /*a proper fraction*/ +int @!h; /*smallest integer such that |2*h >= d|*/ +int @!r; /*intermediate remainder*/ +int @!t; /*temp variable*/ +if (d==0) goto too_big; +a=0; +if (d > 0) negative=false; +else{@+negate(d);negative=true; + } +if (x < 0) + {@+negate(x);negative=!negative; + } +else if (x==0) goto done; +if (n < 0) + {@+negate(n);negative=!negative; + } +t=n/d; +if (t > max_answer/x) goto too_big; +a=t*x;n=n-t*d; +if (n==0) goto found; +t=x/d; +if (t > (max_answer-a)/n) goto too_big; +a=a+t*n;x=x-t*d; +if (x==0) goto found; +if (x < n) + {@+t=x;x=n;n=t; + } /*now |0 < n <= x < d|*/ +@<Compute \(f)$f=\lfloor xn/d+{1\over2}\rfloor$@>@; +if (f > (max_answer-a)) goto too_big; +a=a+f; +found: if (negative) negate(a); +goto done; +too_big: num_error(a); +done: return a; +} + +@ The loop here preserves the following invariant relations +between |f|, |x|, |n|, and~|r|: +(i)~$f+\lfloor(xn+(r+d))/d\rfloor=\lfloor x_0n_0/d+{1\over2}\rfloor$; +(ii)~|-d <= r < 0 < n <= x < d|, where $x_0$, $n_0$ are the original values of~$x$ +and $n$. + +Notice that the computation specifies |(x-d)+x| instead of |(x+x)-d|, +because the latter could overflow. + +@<Compute \(f)$f=\lfloor xn/d+{1\over2}\rfloor$@>= +f=0;r=(d/2)-d;h=-r; +loop@+{@+if (odd(n)) + {@+r=r+x; + if (r >= 0) + {@+r=r-d;incr(f); + } + } + n=n/2; + if (n==0) goto found1; + if (x < h) x=x+x; + else{@+t=x-d;x=t+x;f=f+n; + if (x < n) + {@+if (x==0) goto found1; + t=x;x=n;n=t; + } + } + } +found1: + +@ The \.{\\gluestretch}, \.{\\glueshrink}, \.{\\gluestretchorder}, and +\.{\\glueshrinkorder} commands return the stretch and shrink components +and their orders of ``infinity'' of a glue specification. + +@d glue_stretch_order_code (eTeX_int+6) /*code for \.{\\gluestretchorder}*/ +@d glue_shrink_order_code (eTeX_int+7) /*code for \.{\\glueshrinkorder}*/ +@d glue_stretch_code (eTeX_dim+7) /*code for \.{\\gluestretch}*/ +@d glue_shrink_code (eTeX_dim+8) /*code for \.{\\glueshrink}*/ + +@<Generate all \eTeX...@>= +primitive("gluestretchorder", last_item, glue_stretch_order_code); +@!@:glue\_stretch\_order\_}{\.{\\gluestretchorder} primitive@> +primitive("glueshrinkorder", last_item, glue_shrink_order_code); +@!@:glue\_shrink\_order\_}{\.{\\glueshrinkorder} primitive@> +primitive("gluestretch", last_item, glue_stretch_code); +@!@:glue\_stretch\_}{\.{\\gluestretch} primitive@> +primitive("glueshrink", last_item, glue_shrink_code); +@!@:glue\_shrink\_}{\.{\\glueshrink} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case glue_stretch_order_code: print_esc("gluestretchorder");@+break; +case glue_shrink_order_code: print_esc("glueshrinkorder");@+break; +case glue_stretch_code: print_esc("gluestretch");@+break; +case glue_shrink_code: print_esc("glueshrink");@+break; + +@ @<Cases for fetching an integer value@>= +case glue_stretch_order_code: case glue_shrink_order_code: + {@+scan_normal_glue();q=cur_val; + if (m==glue_stretch_order_code) cur_val=stretch_order(q); + else cur_val=shrink_order(q); + delete_glue_ref(q); + } + +@ @<Cases for fetching a dimension value@>= +case glue_stretch_code: case glue_shrink_code: + {@+scan_normal_glue();q=cur_val; + if (m==glue_stretch_code) cur_val=stretch(q); + else cur_val=shrink(q); + delete_glue_ref(q); + } + +@ The \.{\\mutoglue} and \.{\\gluetomu} commands convert ``math'' glue +into normal glue and vice versa; they allow to manipulate math glue with +\.{\\gluestretch} etc. + +@d mu_to_glue_code eTeX_glue /*code for \.{\\mutoglue}*/ +@d glue_to_mu_code eTeX_mu /*code for \.{\\gluetomu}*/ + +@<Generate all \eTeX...@>= +primitive("mutoglue", last_item, mu_to_glue_code); +@!@:mu\_to\_glue\_}{\.{\\mutoglue} primitive@> +primitive("gluetomu", last_item, glue_to_mu_code); +@!@:glue\_to\_mu\_}{\.{\\gluetomu} primitive@> + +@ @<Cases of |last_item| for |print_cmd_chr|@>= +case mu_to_glue_code: print_esc("mutoglue");@+break; +case glue_to_mu_code: print_esc("gluetomu");@+break; + +@ @<Cases for fetching a glue value@>= +case mu_to_glue_code: scan_mu_glue(); + +@ @<Cases for fetching a mu value@>= +case glue_to_mu_code: scan_normal_glue(); + +@ \eTeX\ (in extended mode) supports 32768 (i.e., $2^{15}$) count, +dimen, skip, muskip, box, and token registers. As in \TeX\ the first +256 registers of each kind are realized as arrays in the table of +equivalents; the additional registers are realized as tree structures +built from variable-size nodes with individual registers existing only +when needed. Default values are used for nonexistent registers: zero +for count and dimen values, |zero_glue| for glue (skip and muskip) +values, void for boxes, and |null| for token lists (and current marks +discussed below). + + +@ The |scan_register_num| procedure scans a register number that must +not exceed 255 in compatibility mode resp.\ 32767 in extended mode. + +@<Declare \eTeX\ procedures for ex...@>= +static void scan_register_num(void); + +@ @<Declare procedures that scan restricted classes of integers@>= +static void scan_register_num(void) +{@+scan_int(); +if ((cur_val < 0)||(cur_val > max_reg_num)) + {@+print_err("Bad register code"); +@.Bad register code@> + help2(max_reg_help_line,"I changed this one to zero."); + int_error(cur_val);cur_val=0; + } +} + +@ @<Initialize variables for \eTeX\ comp...@>= +max_reg_num=255; +max_reg_help_line="A register number must be between 0 and 255."; + +@ @<Initialize variables for \eTeX\ ext...@>= +max_reg_num=32767; +max_reg_help_line="A register number must be between 0 and 32767."; + +@ @<Glob...@>= +static halfword @!max_reg_num; /*largest allowed register number*/ +static char *@!max_reg_help_line; /*first line of help message*/ + +@ There are seven almost identical doubly linked trees, one for the +sparse array of the up to 32512 additional registers of each kind and +one for the sparse array of the up to 32767 additional mark classes. +The root of each such tree, if it exists, is an index node containing 16 +pointers to subtrees for 4096 consecutive array elements. Similar index +nodes are the starting points for all nonempty subtrees for 4096, 256, +and 16 consecutive array elements. These four levels of index nodes are +followed by a fifth level with nodes for the individual array elements. + +Each index node is nine words long. The pointers to the 16 possible +subtrees or are kept in the |info| and |link| fields of the last eight +words. (It would be both elegant and efficient to declare them as +array, unfortunately \PASCAL\ doesn't allow this.) + +The fields in the first word of each index node and in the nodes for the +array elements are closely related. The |link| field points to the next +lower index node and the |sa_index| field contains four bits (one +hexadecimal digit) of the register number or mark class. For the lowest +index node the |link| field is |null| and the |sa_index| field indicates +the type of quantity (|int_val|, |dimen_val|, |glue_val|, |mu_val|, +|box_val|, |tok_val|, or |mark_val|). The |sa_used| field in the index +nodes counts how many of the 16 pointers are non-null. + +The |sa_index| field in the nodes for array elements contains the four +bits plus 16 times the type. Therefore such a node represents a count +or dimen register if and only if |sa_index < dimen_val_limit|; it +represents a skip or muskip register if and only if +|dimen_val_limit <= sa_index < mu_val_limit|; it represents a box register +if and only if |mu_val_limit <= sa_index < box_val_limit|; it represents a +token list register if and only if +|box_val_limit <= sa_index < tok_val_limit|; finally it represents a mark +class if and only if |tok_val_limit <= sa_index|. + +The |new_index| procedure creates an index node (returned in |cur_ptr|) +having given contents of the |sa_index| and |link| fields. + +@d box_val 4 /*the additional box registers*/ +@d mark_val 6 /*the additional mark classes*/ +@# +@d dimen_val_limit 0x20 /*$2^4\cdot(|dimen_val|+1)$*/ +@d mu_val_limit 0x40 /*$2^4\cdot(|mu_val|+1)$*/ +@d box_val_limit 0x50 /*$2^4\cdot(|box_val|+1)$*/ +@d tok_val_limit 0x60 /*$2^4\cdot(|tok_val|+1)$*/ +@# +@d index_node_size 9 /*size of an index node*/ +@d sa_index(A) type(A) /*a four-bit address or a type or both*/ +@d sa_used(A) subtype(A) /*count of non-null pointers*/ + +@<Declare \eTeX\ procedures for ex...@>= +static void new_index(quarterword @!i, pointer @!q) +{@+int k; /*loop index*/ +cur_ptr=get_node(index_node_size);sa_index(cur_ptr)=i; +sa_used(cur_ptr)=0;link(cur_ptr)=q; +for (k=1; k<=index_node_size-1; k++) /*clear all 16 pointers*/ + mem[cur_ptr+k]=sa_null; +} + +@ The roots of the seven trees for the additional registers and mark +classes are kept in the |sa_root| array. The first six locations must +be dumped and undumped; the last one is also known as |sa_mark|. + +@d sa_mark sa_root[mark_val] /*root for mark classes*/ + +@<Glob...@>= +static pointer @!sa_root0[mark_val-int_val+1], *const @!sa_root = @!sa_root0-int_val; /*roots of sparse arrays*/ +static pointer @!cur_ptr; /*value returned by |new_index| and |find_sa_element|*/ +static memory_word @!sa_null; /*two |null| pointers*/ + +@ @<Set init...@>= +sa_mark=null;sa_null.hh.lh=null;sa_null.hh.rh=null; + +@ @<Initialize table...@>= +for (i=int_val; i<=tok_val; i++) sa_root[i]=null; + +@ Given a type |t| and a sixteen-bit number |n|, the |find_sa_element| +procedure returns (in |cur_ptr|) a pointer to the node for the +corresponding array element, or |null| when no such element exists. The +third parameter |w| is set |true| if the element must exist, e.g., +because it is about to be modified. The procedure has two main +branches: one follows the existing tree structure, the other (only used +when |w| is |true|) creates the missing nodes. + +We use macros to extract the four-bit pieces from a sixteen-bit register +number or mark class and to fetch or store one of the 16 pointers from +an index node. + +@d if_cur_ptr_is_null_then_return_or_goto(A) /*some tree element is missing*/ + {@+if (cur_ptr==null) + if (w) goto A;@+else return; + } +@# +@d hex_dig1(A) A/4096 /*the fourth lowest hexadecimal digit*/ +@d hex_dig2(A) (A/256)%16 /*the third lowest hexadecimal digit*/ +@d hex_dig3(A) (A/16)%16 /*the second lowest hexadecimal digit*/ +@d hex_dig4(A) A%16 /*the lowest hexadecimal digit*/ +@# +@d get_sa_ptr if (odd(i)) cur_ptr=link(q+(i/2)+1); + else cur_ptr=info(q+(i/2)+1) + /*set |cur_ptr| to the pointer indexed by |i| from index node |q|*/ +@d put_sa_ptr(A) if (odd(i)) link(q+(i/2)+1)=A; + else info(q+(i/2)+1)=A + /*store the pointer indexed by |i| in index node |q|*/ +@d add_sa_ptr {@+put_sa_ptr(cur_ptr);incr(sa_used(q)); + } /*add |cur_ptr| as the pointer indexed by |i| in index node |q|*/ +@d delete_sa_ptr {@+put_sa_ptr(null);decr(sa_used(q)); + } /*delete the pointer indexed by |i| in index node |q|*/ + +@<Declare \eTeX\ procedures for ex...@>= +static void find_sa_element(small_number @!t, halfword @!n, bool @!w) + /*sets |cur_val| to sparse array element location or |null|*/ +{@+ +pointer q; /*for list manipulations*/ +small_number @!i; /*a four bit index*/ +cur_ptr=sa_root[t]; +if_cur_ptr_is_null_then_return_or_goto(not_found);@/ +q=cur_ptr;i=hex_dig1(n);get_sa_ptr; +if_cur_ptr_is_null_then_return_or_goto(not_found1);@/ +q=cur_ptr;i=hex_dig2(n);get_sa_ptr; +if_cur_ptr_is_null_then_return_or_goto(not_found2);@/ +q=cur_ptr;i=hex_dig3(n);get_sa_ptr; +if_cur_ptr_is_null_then_return_or_goto(not_found3);@/ +q=cur_ptr;i=hex_dig4(n);get_sa_ptr; +if ((cur_ptr==null)&&w) goto not_found4; +return; +not_found: new_index(t, null); /*create first level index node*/ +sa_root[t]=cur_ptr;q=cur_ptr;i=hex_dig1(n); +not_found1: new_index(i, q); /*create second level index node*/ +add_sa_ptr;q=cur_ptr;i=hex_dig2(n); +not_found2: new_index(i, q); /*create third level index node*/ +add_sa_ptr;q=cur_ptr;i=hex_dig3(n); +not_found3: new_index(i, q); /*create fourth level index node*/ +add_sa_ptr;q=cur_ptr;i=hex_dig4(n); +not_found4: @<Create a new array element of type |t| with index |i|@>; +link(cur_ptr)=q;add_sa_ptr; +} + +@ The array elements for registers are subject to grouping and have an +|sa_lev| field (quite analogous to |eq_level|) instead of |sa_used|. +Since saved values as well as shorthand definitions (created by e.g., +\.{\\countdef}) refer to the location of the respective array element, +we need a reference count that is kept in the |sa_ref| field. An array +element can be deleted (together with all references to it) when its +|sa_ref| value is |null| and its value is the default value. +@^reference counts@> + +Skip, muskip, box, and token registers use two word nodes, their values +are stored in the |sa_ptr| field. +Count and dimen registers use three word nodes, their +values are stored in the |sa_int| resp.\ |sa_dim| field in the third +word; the |sa_ptr| field is used under the name |sa_num| to store +the register number. Mark classes use four word nodes. The last three +words contain the five types of current marks + +@d sa_lev sa_used /*grouping level for the current value*/ +@d pointer_node_size 2 /*size of an element with a pointer value*/ +@d sa_type(A) (sa_index(A)/16) /*type part of combined type/index*/ +@d sa_ref(A) info(A+1) /*reference count of a sparse array element*/ +@d sa_ptr(A) link(A+1) /*a pointer value*/ +@# +@d word_node_size 3 /*size of an element with a word value*/ +@d sa_num(A) sa_ptr(A) /*the register number*/ +@d sa_int(A) mem[A+2].i /*an integer*/ +@d sa_dim(A) mem[A+2].sc /*a dimension (a somewhat esotheric distinction)*/ +@# +@d mark_class_node_size 4 /*size of an element for a mark class*/ +@# +@d fetch_box(A) /*fetch |box(cur_val)|*/ + if (cur_val < 256) A=box(cur_val); + else{@+find_sa_element(box_val, cur_val, false); + if (cur_ptr==null) A=null;@+else A=sa_ptr(cur_ptr); + } + +@<Create a new array element...@>= +if (t==mark_val) /*a mark class*/ + {@+cur_ptr=get_node(mark_class_node_size); + mem[cur_ptr+1]=sa_null;mem[cur_ptr+2]=sa_null;mem[cur_ptr+3]=sa_null; + } +else{@+if (t <= dimen_val) /*a count or dimen register*/ + {@+cur_ptr=get_node(word_node_size);sa_int(cur_ptr)=0; + sa_num(cur_ptr)=n; + } + else{@+cur_ptr=get_node(pointer_node_size); + if (t <= mu_val) /*a skip or muskip register*/ + {@+sa_ptr(cur_ptr)=zero_glue;add_glue_ref(zero_glue); + } + else sa_ptr(cur_ptr)=null; /*a box or token list register*/ + } + sa_ref(cur_ptr)=null; /*all registers have a reference count*/ + } +sa_index(cur_ptr)=16*t+i;sa_lev(cur_ptr)=level_one + +@ The |delete_sa_ref| procedure is called when a pointer to an array +element representing a register is being removed; this means that the +reference count should be decreased by one. If the reduced reference +count is |null| and the register has been (globally) assigned its +default value the array element should disappear, possibly together with +some index nodes. This procedure will never be used for mark class +nodes. +@^reference counts@> + +@d add_sa_ref(A) incr(sa_ref(A)) /*increase reference count*/ +@# +@d change_box(A) /*change |box(cur_val)|, the |eq_level| stays the same*/ + if (cur_val < 256) box(cur_val)=A;@+else set_sa_box(A) +@# +@d set_sa_box(X) {@+find_sa_element(box_val, cur_val, false); + if (cur_ptr!=null) + {@+sa_ptr(cur_ptr)=X;add_sa_ref(cur_ptr);delete_sa_ref(cur_ptr); + } + } + +@<Declare \eTeX\ procedures for tr...@>= +static void delete_sa_ref(pointer @!q) /*reduce reference count*/ +{@+ +pointer p; /*for list manipulations*/ +small_number @!i; /*a four bit index*/ +small_number @!s; /*size of a node*/ +decr(sa_ref(q)); +if (sa_ref(q)!=null) return; +if (sa_index(q) < dimen_val_limit) + if (sa_int(q)==0) s=word_node_size; + else return; +else{@+if (sa_index(q) < mu_val_limit) + if (sa_ptr(q)==zero_glue) delete_glue_ref(zero_glue); + else return; + else if (sa_ptr(q)!=null) return; + s=pointer_node_size; + } +@/do@+{i=hex_dig4(sa_index(q));p=q;q=link(p);free_node(p, s); +if (q==null) /*the whole tree has been freed*/ + {@+sa_root[i]=null;return; + } +delete_sa_ptr;s=index_node_size; /*node |q| is an index node*/ +}@+ while (!(sa_used(q) > 0)); +} + +@ The |print_sa_num| procedure prints the register number corresponding +to an array element. + +@<Basic print...@>= +static void print_sa_num(pointer @!q) /*print register number*/ +{@+halfword @!n; /*the register number*/ +if (sa_index(q) < dimen_val_limit) n=sa_num(q); /*the easy case*/ +else{@+n=hex_dig4(sa_index(q));q=link(q);n=n+16*sa_index(q); + q=link(q);n=n+256*(sa_index(q)+16*sa_index(link(q))); + } +print_int(n); +} + +@ Here is a procedure that displays the contents of an array element +symbolically. It is used under similar circumstances as is +|restore_trace| (together with |show_eqtb|) for the quantities kept in +the |eqtb| array. + +@<Declare \eTeX\ procedures for tr...@>= +#ifdef @!STAT +static void show_sa(pointer @!p, char *@!s) +{@+small_number t; /*the type of element*/ +begin_diagnostic();print_char('{');print(s);print_char(' '); +if (p==null) print_char('?'); /*this can't happen*/ +else{@+t=sa_type(p); + if (t < box_val) print_cmd_chr(internal_register, p); + else if (t==box_val) + {@+print_esc("box");print_sa_num(p); + } + else if (t==tok_val) print_cmd_chr(toks_register, p); + else print_char('?'); /*this can't happen either*/ + print_char('='); + if (t==int_val) print_int(sa_int(p)); + else if (t==dimen_val) + {@+print_scaled(sa_dim(p));print("pt"); + } + else{@+p=sa_ptr(p); + if (t==glue_val) print_spec(p,"pt"); + else if (t==mu_val) print_spec(p,"mu"); + else if (t==box_val) + if (p==null) print("void"); + else{@+depth_threshold=0;breadth_max=1;show_node_list(p); + } + else if (t==tok_val) + {@+if (p!=null) show_token_list(link(p), null, 32); + } + else print_char('?'); /*this can't happen either*/ + } + } +print_char('}');end_diagnostic(false); +} +#endif + + + +@ The command code |internal_register| is used for `\.{\\count}', `\.{\\dimen}', +etc., as well as for references to sparse array elements defined by +`\.{\\countdef}', etc. + +@<Cases of |register| for |print_cmd_chr|@>= +{@+if ((chr_code < mem_bot)||(chr_code > lo_mem_stat_max)) + cmd=sa_type(chr_code); +else{@+cmd=chr_code-mem_bot;chr_code=null; + } +if (cmd==int_val) print_esc("count"); +else if (cmd==dimen_val) print_esc("dimen"); +else if (cmd==glue_val) print_esc("skip"); +else print_esc("muskip"); +if (chr_code!=null) print_sa_num(chr_code); +} + +@ Similarly the command code |toks_register| is used for `\.{\\toks}' as +well as for references to sparse array elements defined by +`\.{\\toksdef}'. + +@<Cases of |toks_register| for |print_cmd_chr|@>= +{@+print_esc("toks"); +if (chr_code!=mem_bot) print_sa_num(chr_code); +} + +@ When a shorthand definition for an element of one of the sparse arrays +is destroyed, we must reduce the reference count. + +@<Cases for |eq_destroy|@>= +case toks_register: case internal_register: + if ((equiv_field(w) < mem_bot)||(equiv_field(w) > lo_mem_stat_max)) + delete_sa_ref(equiv_field(w));@+break; + +@ The task to maintain (change, save, and restore) register values is +essentially the same when the register is realized as sparse array +element or entry in |eqtb|. The global variable |sa_chain| is the head +of a linked list of entries saved at the topmost level |sa_level|; the +lists for lowel levels are kept in special save stack entries. + +@<Glob...@>= +static pointer @!sa_chain; /*chain of saved sparse array entries*/ +static quarterword @!sa_level; /*group level for |sa_chain|*/ + +@ @<Set init...@>= +sa_chain=null;sa_level=level_zero; + +@ The individual saved items are kept in pointer or word nodes similar +to those used for the array elements: a word node with value zero is, +however, saved as pointer node with the otherwise impossible |sa_index| +value |tok_val_limit|. + +@d sa_loc(A) sa_ref(A) /*location of saved item*/ + +@<Declare \eTeX\ procedures for tr...@>= +static void sa_save(pointer @!p) /*saves value of |p|*/ +{@+pointer q; /*the new save node*/ +quarterword @!i; /*index field of node*/ +if (cur_level!=sa_level) + {@+check_full_save_stack;save_type(save_ptr)=restore_sa; + save_level(save_ptr)=sa_level;save_index(save_ptr)=sa_chain; + incr(save_ptr);sa_chain=null;sa_level=cur_level; + } +i=sa_index(p); +if (i < dimen_val_limit) + {@+if (sa_int(p)==0) + {@+q=get_node(pointer_node_size);i=tok_val_limit; + } + else{@+q=get_node(word_node_size);sa_int(q)=sa_int(p); + } + sa_ptr(q)=null; + } +else{@+q=get_node(pointer_node_size);sa_ptr(q)=sa_ptr(p); + } +sa_loc(q)=p;sa_index(q)=i;sa_lev(q)=sa_lev(p); +link(q)=sa_chain;sa_chain=q;add_sa_ref(p); +} + +@ @<Declare \eTeX\ procedures for tr...@>= +static void sa_destroy(pointer @!p) /*destroy value of |p|*/ +{@+if (sa_index(p) < mu_val_limit) delete_glue_ref(sa_ptr(p)); +else if (sa_ptr(p)!=null) + if (sa_index(p) < box_val_limit) flush_node_list(sa_ptr(p)); + else delete_token_ref(sa_ptr(p)); +} + +@ The procedure |sa_def| assigns a new value to sparse array elements, +and saves the former value if appropriate. This procedure is used only +for skip, muskip, box, and token list registers. The counterpart of +|sa_def| for count and dimen registers is called |sa_w_def|. + +@d sa_define(A, B, C, D, E) if (e) + if (global) gsa_def(A, B);@+else sa_def(A, B); + else if (global) geq_define(C, D, E);@+else eq_define(C, D, E) +@# +@d sa_def_box /*assign |cur_box| to |box(cur_val)|*/ + {@+find_sa_element(box_val, cur_val, true); + if (global) gsa_def(cur_ptr, cur_box);@+else sa_def(cur_ptr, cur_box); + } +@# +@d sa_word_define(A, B) if (e) + if (global) gsa_w_def(A, B);@+else sa_w_def(A, B); + else word_define(A, B) + +@<Declare \eTeX\ procedures for tr...@>= +static void sa_def(pointer @!p, halfword @!e) + /*new data for sparse array elements*/ +{@+add_sa_ref(p); +if (sa_ptr(p)==e) + { +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"reassigning"); +#endif +@;@/ + sa_destroy(p); + } +else{ +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"changing"); +#endif +@;@/ + if (sa_lev(p)==cur_level) sa_destroy(p);@+else sa_save(p); + sa_lev(p)=cur_level;sa_ptr(p)=e; +#ifdef @!STAT + if (tracing_assigns > 0) show_sa(p,"into"); +#endif +@;@/ + } +delete_sa_ref(p); +} +@# +static void sa_w_def(pointer @!p, int @!w) +{@+add_sa_ref(p); +if (sa_int(p)==w) + { +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"reassigning"); +#endif +@;@/ + } +else{ +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"changing"); +#endif +@;@/ + if (sa_lev(p)!=cur_level) sa_save(p); + sa_lev(p)=cur_level;sa_int(p)=w; +#ifdef @!STAT + if (tracing_assigns > 0) show_sa(p,"into"); +#endif +@;@/ + } +delete_sa_ref(p); +} + +@ The |sa_def| and |sa_w_def| routines take care of local definitions. +@^global definitions@> +Global definitions are done in almost the same way, but there is no need +to save old values, and the new value is associated with |level_one|. + +@<Declare \eTeX\ procedures for tr...@>= +static void gsa_def(pointer @!p, halfword @!e) /*global |sa_def|*/ +{@+add_sa_ref(p); +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"globally changing"); +#endif +@;@/ +sa_destroy(p);sa_lev(p)=level_one;sa_ptr(p)=e; +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"into"); +#endif +@;@/ +delete_sa_ref(p); +} +@# +static void gsa_w_def(pointer @!p, int @!w) /*global |sa_w_def|*/ +{@+add_sa_ref(p); +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"globally changing"); +#endif +@;@/ +sa_lev(p)=level_one;sa_int(p)=w; +#ifdef @!STAT +if (tracing_assigns > 0) show_sa(p,"into"); +#endif +@;@/ +delete_sa_ref(p); +} + +@ The |sa_restore| procedure restores the sparse array entries pointed +at by |sa_chain| + +@<Declare \eTeX\ procedures for tr...@>= +static void sa_restore(void) +{@+pointer p; /*sparse array element*/ +@/do@+{p=sa_loc(sa_chain); +if (sa_lev(p)==level_one) + {@+if (sa_index(p) >= dimen_val_limit) sa_destroy(sa_chain); +#ifdef @!STAT + if (tracing_restores > 0) show_sa(p,"retaining"); +#endif +@;@/ + } +else{@+if (sa_index(p) < dimen_val_limit) + if (sa_index(sa_chain) < dimen_val_limit) sa_int(p)=sa_int(sa_chain); + else sa_int(p)=0; + else{@+sa_destroy(p);sa_ptr(p)=sa_ptr(sa_chain); + } + sa_lev(p)=sa_lev(sa_chain); +#ifdef @!STAT + if (tracing_restores > 0) show_sa(p,"restoring"); +#endif +@;@/ + } +delete_sa_ref(p); +p=sa_chain;sa_chain=link(p); +if (sa_index(p) < dimen_val_limit) free_node(p, word_node_size); +else free_node(p, pointer_node_size); +}@+ while (!(sa_chain==null)); +} + + +@ The \.{\\interlinepenalties}, \.{\\clubpenalties}, \.{\\widowpenalties}, +and \.{\\displaywidowpenalties} commands allow to define arrays of +penalty values to be used instead of the corresponding single values. + +@d inter_line_penalties_ptr equiv(inter_line_penalties_loc) +@<Generate all \eTeX...@>= +primitive("interlinepenalties", set_shape, inter_line_penalties_loc);@/ +@!@:inter\_line\_penalties\_}{\.{\\interlinepenalties} primitive@> +primitive("clubpenalties", set_shape, club_penalties_loc);@/ +@!@:club\_penalties\_}{\.{\\clubpenalties} primitive@> +primitive("widowpenalties", set_shape, widow_penalties_loc);@/ +@!@:widow\_penalties\_}{\.{\\widowpenalties} primitive@> +primitive("displaywidowpenalties", set_shape, display_widow_penalties_loc);@/ +@!@:display\_widow\_penalties\_}{\.{\\displaywidowpenalties} primitive@> + +@ @<Cases of |set_shape| for |print_cmd_chr|@>= +case inter_line_penalties_loc: print_esc("interlinepenalties");@+break; +case club_penalties_loc: print_esc("clubpenalties");@+break; +case widow_penalties_loc: print_esc("widowpenalties");@+break; +case display_widow_penalties_loc: print_esc("displaywidowpenalties"); + +@ @<Fetch a penalties array element@>= +{@+scan_int(); +if ((equiv(m)==null)||(cur_val < 0)) cur_val=0; +else{@+if (cur_val > penalty(equiv(m))) cur_val=penalty(equiv(m)); + cur_val=penalty(equiv(m)+cur_val); + } +} + +@* System-dependent changes. +This section should be replaced, if necessary, by any special +modifications of the program +that are necessary to make \TeX\ work at a particular installation. +It is usually best to design your change file so that all changes to +previous sections preserve the section numbering; then everybody's version +will be consistent with the published program. More extensive changes, +which introduce new sections, can be inserted here; then only the index +itself will get a new section number. +@^system dependencies@> + +@* \TeX\ Live Integration. +A \TeX\ engine that aspires +to become a member of the \TeX\ Live family of programs +must + +$-$ respect the \TeX\ Live conventions for command line parameters,\par +$-$ find its input files using the \.{kpathsearch} library, and\par +$-$ implement \TeX\ primitives to support +\def\LaTeX{L\kern-.36em\raise.3ex\hbox{\sc A}\kern-.15em\TeX}% +\LaTeX. + +\noindent Naturally, the functions that follow here are taken, with small +modifications, from the \TeX\ Live sources. What is +added here, or rather subtracted here, are the parts that are specific +to some of the \TeX\ engines included in \TeX\ Live. New is also +that the code is presented in literate programming style. + +The code that follows is organized in three parts. +Some code for k\TeX\ must come before +the definition of \TeX's macros because +it uses include files containing identifiers that are in conflict +with \TeX's macros. The remaining two parts are first auxiliar functions and then +those functions that are called from the ``classic'' \TeX\ code. + +@p @<k\TeX\ auxiliar functions@>@; + @<k\TeX\ functions@>@; + +@ Let's begin with the beginning: the command line. +To see how a command line is structured, we first look at the +help text that is displayed if the user asks for it (or if \TeX\ +decides that the user needs it). The help text is produced by the +function |usage_help|. +\def\SP{ }% disable visible spaces in strings. + +@<k\TeX\ auxiliar functions@>= +static void usage_help(void) +{@+@<explain the command line@>@; + @<explain the options@>@; + fprintf(stderr,"\nEmail bug reports to ruckert@@cs.hm.edu.\n"); + exit(0); +} + +@ The command line commes in three slightly different versions: + +@<explain the command line@>= + fprintf(stderr,@/ + "Usage: %s [OPTION]... [TEXNAME[.tex]] [COMMANDS]\n"@/ + " or: %s [OPTION]... \\FIRST-LINE\n"@/ + " or: %s [OPTION]... &FMT ARGS\n\n",@/ + argv[0],argv[0],argv[0]);@/ + fprintf(stderr,@/ + " Run TeX on TEXNAME, creating TEXNAME.dvi.\n"@/ + " Any remaining COMMANDS are processed\n"@/ + " as TeX input after TEXNAME is read.\n"@/ + " If the first line of TEXNAME starts with %%&FMT, and FMT is\n"@/ + " an existing .fmt file, use it. Else use `NAME.fmt', where\n"@/ + " NAME is the program invocation name.\n"@/ + "\n"@/ + " Alternatively, if the first non-option argument begins\n"@/ + " with a backslash, interpret all non-option arguments as\n"@/ + " a line of TeX input.\n"@/ + "\n"@/ + " Alternatively, if the first non-option argument begins\n"@/ + " with a &, the next word is taken as the FMT to read,\n"@/ + " overriding all else. Any remaining arguments are\n"@/ + " processed as above.\n"@/ + "\n"@/ + " If no arguments or options are specified, prompt for input.\n"@/ + "\n"); + +@ Here is the list of possible options and their explanation: + +@<explain the options@>= + fprintf(stderr, + "Options:\n"@/ + " -help "@/ + @t\qquad@>"\t display this help and exit\n"@/ + " -version "@/ + @t\qquad@>"\t output version information and exit\n"@/ + " -etex "@/ + @t\qquad@>"\t enable e-TeX extensions\n"@/ + " -ini "@/ + @t\qquad@>"\t be initex for dumping formats; this is\n"@/ + @t\qquad@>"\t\t\t also true if the program name is `kinitex'\n"@/ + " -progname=STRING "@/ + @t\qquad@>"\t set program (and fmt) name to STRING\n"@/ + " -fmt=FMTNAME "@/ + @t\qquad@>"\t use FMTNAME instead of program name or a %%& line\n"@/ + " -output-directory=DIR "@/ + @t\qquad@>"\t use existing DIR as the directory to write files to\n"@/ + " -jobname=STRING "@/ + @t\qquad@>"\t set the TeX \\jobname to STRING\n"@/ + " [-no]-mktex=FMT "@/ + @t\qquad@>"\t disable/enable mktexFMT generation (FMT=tex/tfm/fmt/pk)\n"@/ + " -interaction=STRING "@/ + @t\qquad@>"\t set interaction mode (STRING=batchmode/\n"@/ + @t\qquad@>"\t\t\t nonstopmode/scrollmode/errorstopmode)\n"@/ + " -kpathsea-debug=NUMBER"@/ + @t\qquad@>"\t set path searching debugging flags according\n"@/ + @t\qquad@>"\t\t\t to the bits of NUMBER\n"@/ + " [-no]-parse-first-line"@/ + @t\qquad@>"\t disable/enable parsing of the first line of\n"@/ + @t\qquad@>"\t\t\t the input file\n"@/ + " [-no]-file-line-error"@/ + @t\qquad@>"\t Disable/Enable file:line:error style\n"@/ + " -cnf-line=STRING"@/ + @t\qquad@>"\t Process STRING like a line in texmf.cnf\n"@/ + " -compress "@/ + @t\qquad@>"\t enable compression of section 1 and 2\n"@/ + " [-no]-empty-page "@/ + @t\qquad@>"\t Disable/Enable empty pages\n"@/ + " -hyphenate-first-word "@/ + @t\qquad@>"\t hyphenate the first word of a paragraph\n"@/ + " -resolution=NUMBER "@/ + @t\qquad@>"\t set the resolution to NUMBER dpi\n"@/ + " -mfmode=MODE "@/ + @t\qquad@>"\t set the METAFONT mode to MODE\n"@/ +#ifdef DEBUG + " -debug=FLAGS "@/ + @t\qquad@>"\t set flags to controll hint debug output\n"@/ + " -hint-debug-help "@/ + @t\qquad@>"\t give help on hint debugging\n"@/ +#endif +); + + +@ The processing of command line options is controlled by the |long_options| +\def\SP{{\tt\char`\ }}% restore the visible space in a string +array. Each entry in this array contains first the name of the option, +then a flag that tells whether the option takes an argument or not, +then the (optional) address of a flag variable that gets set +by this option, and finally the value to store in the flag variable. + +Besides the flag variables that occur in the table, +a few string variables may be set using the options. +The following is a complete list of these variables---except +for the the |interaction| variable of \TeX. +Flag variables are initialized with |-1| to indicate an undefined value; +string variables are initialized with |NULL|. + +@<Global...@>= +static int iniversion=0; +static int etexp=0; +static int parsefirstlinep=-1; +static int filelineerrorstylep=-1; +static const char *user_progname=NULL, *output_directory=NULL, *c_job_name=NULL; +static char *dump_name=NULL;@# +int option_no_empty_page=true, option_hyphen_first=false; +int option_dpi=600; +const char *option_mfmode="ljfour", *option_dpi_str="600"; +extern int option_compress; +extern unsigned int debugflags; + +static struct option long_options[] = {@/ + { "help", 0, 0, 0 },@/ + { "version", 0, 0, 0 },@/ + { "interaction", 1, 0, 0 },@/ + { "mktex", 1, 0, 0 },@/ + { "no-mktex", 1, 0, 0 },@/ + { "kpathsea-debug", 1, 0, 0 },@/ + { "progname", 1, 0, 0 },@/ + { "fmt", 1, 0, 0 },@/ + { "output-directory", 1, 0, 0 },@/ + { "jobname", 1, 0, 0 },@/ + { "cnf-line", 1, 0, 0 },@/ + { "ini", 0, &iniversion, 1 },@/ + { "etex", 0, &etexp, 1 },@/ + { "parse-first-line", 0, &parsefirstlinep, 1 },@/ + { "no-parse-first-line", 0, &parsefirstlinep, 0 },@/ + { "file-line-error", 0, &filelineerrorstylep, 1 },@/ + { "no-file-line-error", 0, &filelineerrorstylep, 0 },@/ + { "compress", 0, &option_compress, 1 },@/ + { "no-empty-page", 0, &option_no_empty_page, 1 },@/ + { "empty-page", 0, &option_no_empty_page, 0 },@/ + { "hyphenate-first-word", 0, &option_hyphen_first, 1 },@/ + { "resolution", 1, 0, 0 },@/ + { "mfmode", 1, 0, 0 },@/ +#ifdef DEBUG + { "debug", 1, 0, 0 },@/ + { "hint-debug-help", 0, 0, 0 },@/ +#endif + { 0, 0, 0, 0 }@+}@+; + + +@ Parsing the command line options is accomplished with the +|parse_options| function which in turn uses the |getopt_long_only| +function from the \CEE/ library. This function returns 0 and sets the +|option_index| parameter to the option found, or it returns $-1$ if +the end of all options is reached. +@<k\TeX\ functions@>= +static void parse_options (int argc, char *argv[]) +{@+ while (true) { + int option_index; + int g = getopt_long_only (argc, argv, "+", long_options, &option_index); + if (g==0) + { @<handle the option at |option_index|@>@;@+ } + else if (g == -1) return; + } +} + +@ To handle the options, we compare the name at the given |option_index| with +the different option names. This is not a very efficient method, but the +impact is low and it's simple to write. + +Comparing the name of the argument with the |name| field in the |option| +structure is done in the auxiliar function |argument_is|. +Unfortunately the |name| field is in conflict with the |name| macro +defined by \TeX. To avoid the conflict, the |argument_is| function +goes just after the \.{kpathsea.h} header file that defines +the option structure. + + +@<Header files and function declarations@>= +#include <kpathsea/kpathsea.h> +static int argument_is(struct option *opt, char * s) +{@+ return STREQ(opt->name, s); @+} +#define ARGUMENT_IS(S) argument_is(long_options+option_index,S) + +@ Now we can handle the first two options: +@<handle the option at |option_index|@>= +if (ARGUMENT_IS("help")) usage_help(); +else if (ARGUMENT_IS("version")){@+ + printf("Version 0.0\n"); + exit(0);@+ +} + + +@ The ``interaction'' option sets \TeX's |interaction| variable +based on its string argument contained in the |optarg| variable. + +@<handle the option at |option_index|@>= +else @+if (ARGUMENT_IS ("interaction"))@t\2@> { + if (STREQ (optarg, "batchmode")) interaction = batch_mode; + else if (STREQ (optarg, "nonstopmode")) interaction = nonstop_mode; + else if (STREQ (optarg, "scrollmode")) interaction = scroll_mode; + else if (STREQ (optarg, "errorstopmode")) interaction = error_stop_mode; + else WARNING1 ("Ignoring unknown argument `%s' to --interaction", optarg); + } + +@ The next two options pass the string argument to the +\.{kpathsearch} library. + +@<handle the option at |option_index|@>= +else @+if (ARGUMENT_IS ("mktex")) @t\2@> kpse_maketex_option (optarg, true); +else if (ARGUMENT_IS ("no-mktex")) kpse_maketex_option (optarg, false); + + +@ To debug the searching done by the \.{kpathsearch} library, +the following otion can be used. +The argument value 3 is a good choice to start with. + +@<handle the option at |option_index|@>= +else @+if (ARGUMENT_IS ("kpathsea-debug")) @t\2@> + kpathsea_debug |= atoi (optarg); + + +@ The remaining options either set a flag and are handled by +the |getopt_long_only| function or they take a string argument +and assign it to the corresponding string variable. + +@<handle the option at |option_index|@>= +else @+if (ARGUMENT_IS ("progname"))@t\2@> + user_progname = normalize_quotes(optarg,"program name"); +else if (ARGUMENT_IS ("fmt")) + dump_name = normalize_quotes(optarg,"format name"); +else if (ARGUMENT_IS ("output-directory")) + output_directory = normalize_quotes(optarg,"output directory"); +else if (ARGUMENT_IS ("jobname")) + c_job_name = normalize_quotes (optarg, "job name"); +else @+if (ARGUMENT_IS ("cnf-line")) + add_cnf_line(optarg);@t\2@> +else if (ARGUMENT_IS("resolution")) @t\2@> +{ option_dpi_str=optarg; + option_dpi=strtol(option_dpi_str,NULL,10); +} +else if (ARGUMENT_IS("mfmode")) + option_mfmode=optarg; +#ifdef DEBUG@t\1@> +else @+if (ARGUMENT_IS("debug")) + debugflags=strtol(optarg,NULL,16); +else @+if (ARGUMENT_IS("hint-debug-help")) + hint_debug_help(); +#endif + +@ When string arguments specify files or directories, +special care is needed if arguments are quoted and/or contain spaces. +The function |normalize_quotes| makes shure that arguments containing +spaces get quotes around them and it checks for unballanced quotes. + + +@<k\TeX\ auxiliar functions@>= +static char *normalize_quotes (const char *nom, const char *mesg) +{@+ int quoted = false; + int must_quote = (strchr(nom, ' ') != NULL); + char *ret = xmalloc(strlen(nom)+3);/*room for two quotes and NUL*/ + char *p=ret; + const char *q; + + if (must_quote) + *p++ = '"'; + for (q = nom; *q; q++) + if (*q == '"') + quoted = !quoted;@+ + else + *p++ = *q; + + if (must_quote) + *p++ = '"'; + *p = '\0'; + if (quoted) { + fprintf(stderr, "! Unbalanced quotes in %s %s\n", mesg, nom); + exit(1); + } + return ret; +} + +@ With the \.{-cnf-line} option it is possible to specify +a line of text as if this line were part of \TeX's configuration +file---even taking precedence over conflicting lines in the configuration +file. For example it is possible to change \TeX's +\.{TEXINPUTS} variable by saying \.{--cnf-line=TEXINPUTS=/foo}. +The configuration lines are temporarily stored in the variable +|cnf_lines| and counted in |cnf_count| because we can send them +to the \.{kpathsearch} library only after the library has been +initialized sufficiently. + +@<Global...@>= +char **cnf_lines=NULL; +int cnf_count=0; + +@ The function |add_cnf_line| stores the +given command line argument in the variable |cnf_lines|. + +@<k\TeX\ auxiliar functions@>= +static void add_cnf_line(char *arg) +{@+ cnf_count++; + cnf_lines=xrealloc(cnf_lines,sizeof(char*)*cnf_count); + cnf_lines[cnf_count-1]=arg; +} + +@ To activate the configuration lines they are passed to the + \.{kpathsearch} library. + +@<activate configuration lines@>= +#if 0 /* this function does not exists allways */ +{@+ int i; + for (i=0;i<cnf_count;i++) + kpathsea_cnf_line_env_progname (kpse_def, cnf_lines[i]); + free(cnf_lines); +} +#endif + +@ After we are done with the options, +we inform the \.{kpathsearch} library about the program name. +This is an important piece of information for the library +because the library serves quite different programs +and its behaviour can be customized for each program +using configuration files. +After the program and engine name is set, +the library is ready to use. +@<set the program and engine name@>= +if (!user_progname) + user_progname = dump_name; +#if defined(WIN32) + if (user_progname) + kpse_reset_program_name (user_progname); +#else + kpse_set_program_name (argv[0], user_progname); +#endif + xputenv ("engine", "hitex");@/ + + +@ After the options, the command line usually continues with the name of the input +file. Getting a hold of the input file name can be quite complicated, +and we will have the first opportunity to use the \.{kpathsearch} library. + +We start by looking at the first argument after the options: +If it does not start with an +``\.{\AM}'' and neither with a ``\.{\BS}'', it's a simple file name. +Under Windows, however, filenames might start with a drive letter +followed by a colon and a ``\.{\BS}'' which is used to separate +directory names. Finally, if the filename is a quoted string, we need +to remove the quotes before we use the \.{kpathsearch} library to find it +and reattach the quotes afterwards. + +@<k\TeX\ auxiliar functions@>= +#ifdef WIN32 +static void clean_windows_filename(char *filename) +{@+if (strlen (filename) > 2 && isalpha (filename[0]) && + filename[1] == ':' && filename[2] == '\\') + { char *pp; + for (pp = filename; *pp; pp++) + if (*pp == '\\') + *pp = '/'; + } +} +#endif + +static char *find_file(char *fname, kpse_file_format_type t, int mx) +{@+char *filename; + int final_quote=(int)strlen(fname)-1; + int quoted = final_quote>1 && fname[0] == '"' && fname[final_quote]=='"'; + if (quoted) { + /* Overwrite last quote and skip first quote. */ + fname[final_quote] = '\0'; + fname++; + } + filename = kpse_find_file(fname, t, mx); + if (quoted) { + /* Undo modifications */ + fname--; + fname[final_quote] = '"'; + } + return filename; +} + +static char *get_input_file_name (void) +{@+ + char *input_file_name = NULL; + + if (argv[optind] && argv[optind][0] != '&' && argv[optind][0] != '\\') + { +#ifdef WIN32 + clean_windows_filename(argv[optind]); +#endif + argv[optind] = normalize_quotes(argv[optind], "input file"); + input_file_name=find_file(argv[optind],kpse_tex_format, false); + } + return input_file_name; +} + + +@ After we called |get_input_file_name|, we might need to look at |argv[argc-1]| +in case we run under Windows. + +@<set the input file name@>= + main_input_file = get_input_file_name (); + +#ifdef WIN32 + /* Were we given a simple filename? */ + if (main_input_file == NULL) { + char *file_name=argv[argc-1]; + if (file_name && file_name[0] != '-' && file_name[0] != '&' && file_name[0] != '\\') { + clean_windows_filename(file_name); + file_name = normalize_quotes(file_name, "argument"); + main_input_file=find_file(file_name,kpse_tex_format, false); + argv[argc-1] = file_name; + } + } +#endif + + +@ After we have an input file, we make an attempt at filling in options +from the {\tt texmf.cfg} file. + +@<set defaults from the {\tt texmf.cfg} file@>= + if (filelineerrorstylep < 0) + filelineerrorstylep = texmf_yesno ("file_line_error_style"); + if (parsefirstlinep < 0) + parsefirstlinep = texmf_yesno ("parse_first_line");@/@t~@> + +@ We needed: +@<k\TeX\ auxiliar functions@>= +static int texmf_yesno(const char *var) +{@+ + char *value = kpse_var_value (var); + return value && (*value == 't' || *value == 'y' || *value == '1'); +} + +@ We need a stack, matching the |line_stack| that +contains the source file names; +we postpone k\TeX\'s |full_source_filename_stack| to a later time. + +@<Global...@>= +int @!source_filename_stack0[max_in_open], *const @!source_filename_stack = @!source_filename_stack0-1; + +@ The function |print_file_line| +prints ``file:line:error'' style messages. It looks for a +filename in |source_filename_stack|, and if it fails to find +one falls back on the ``non-file:line:error'' style. + +@<Basic printing...@>= +static void print_file_line(void) +{@+int level=in_open; + while (level>0 && source_filename_stack[level]==0) level--; + if (level==0) print_nl("! "); + else + { print_nl(""); printn(source_filename_stack[level]); print_char(':'); + if (level==in_open) print_int(line); + else print_int(line_stack[level]); + print(": "); + } +} + +@ Most of the time \TeX\ is not running as \.{initex} or \.{virtex}, +but it runs with a format file preloaded. +To set the format name, we first check if the format name was given on the +command line with an ``\.{\AM}'' prefix, +second we might check the first line of the input file, +and last, we check if the program is an initex or virtex program. + +If we still don't have a format, +we use a plain format if running as a virtex, otherwise the program +name is our best guess. +There is no need to check for an extension, because the +\.{kpathsearch} library will take care of that. +We store the format file name in |dump_name| which is +used in the function |w_open_in| below. + +@<set the format name@>= +if (parsefirstlinep && !dump_name) + parse_first_line (main_input_file); +if (!main_input_file && argv[1] && argv[1][0] == '&') + dump_name = argv[1] + 1; +if (strcmp(kpse_program_name, "hinitex")==0) iniversion = true; +else if (strcmp(kpse_program_name, "hvirtex")==0 && !dump_name) + dump_name = "hitex"; +if (!dump_name) + dump_name = kpse_program_name; +if (!dump_name) +{ fprintf(stderr,"Unable to determine format name\n"); + exit(1); +} +if (etexp && !iniversion) +{ fprintf(stderr,"-etex requires -ini\n"); + exit(1); +} + +@ Here is the function |parse_first_line |. It searches the first line of +the file for a \TeX\ comment of the form ``\%\AM format''\footnote{${}^1$}{The idea of using this format came from Wlodzimierz Bzyl.}. +If found, we will use the format given there. + +@<k\TeX\ functions@>= +static void parse_first_line (char*filename) +{@+ FILE *f=NULL; + if (filename==NULL) return; + f = open_in(filename,kpse_tex_format,"r"); + if (f!=NULL) + { char *r,*s,*t=read_line (f); + xfclose (f, filename); + if (t==NULL) return; + s=t; + if (s[0] == '%' && s[1] == '&') { + s = s+2; + while ( ISBLANK(*s)) ++s; + r=s; + while (*s!=0 && *s!=' ' && *s!='\r' && *s!='\n') s++; + *s=0; + if (dump_name==NULL) { + char *f_name = concat (r, ".fmt"); + char *d_name = kpse_find_file (f_name,kpse_fmt_format, false); + if (d_name && kpse_readable_file (d_name)) { + dump_name = xstrdup (r); + kpse_reset_program_name (dump_name); + } + free (f_name); + } + } + free (t); + } +} + + +@ The \TeX\ Live infrastructure is able to generate format files, +font metric files, +and even some tex files, if required. + +@<enable the generation of input files@>= + kpse_set_program_enabled (kpse_tfm_format, MAKE_TEX_TFM_BY_DEFAULT, + kpse_src_compile);@/ + kpse_set_program_enabled (kpse_tex_format, MAKE_TEX_TEX_BY_DEFAULT, + kpse_src_compile);@/ + kpse_set_program_enabled (kpse_fmt_format, MAKE_TEX_FMT_BY_DEFAULT, + kpse_src_compile);@/ + kpse_set_program_enabled (kpse_pk_format, MAKE_TEX_PK_BY_DEFAULT, + kpse_src_compile);@/ + xputenv("MAKETEX_BASE_DPI", option_dpi_str); + xputenv("MAKETEX_MODE", option_mfmode); + + +@ In the old days, \TeX\ was a \PASCAL\ program, and standard \PASCAL\ +did say nothing about a command line. So \TeX\ would open the terminal +file for input and read all the information from the terminal. +If you don't give \TeX\ command line arguments, this is still true today. +In our present time, people got so much used to control the behaviour +of a program using command line arguments---especially when writing +scripts---that k\TeX\ allows the specification of commands on +the command line which \TeX\ would normally expect on +the first line of its terminal input. + +So our next task is +writing a function to add the remainder of the +command line to \TeX's input buffer. +The main job is done by the |input_add_str| function +which duplicates part of the |input_ln| function. +Further it skips initial spaces and replaces trailing spaces +and line endings by a single space. + +@<k\TeX\ auxiliar functions@>= +static void input_add_char(unsigned int c) +{@+ if (last >= max_buf_stack) + {@+max_buf_stack=last+1; + if (max_buf_stack==buf_size) + @<Report overflow of the input buffer, and abort@>; + } + buffer[last]=xord[c];incr(last); +} + +static void input_add_str(const char *str) +{@+ int prev_last; + while (*str==' ') str++; + prev_last=last; + while (*str!=0) + +input_add_char(*str++); + for (--last; last >= first ; --last) + { char c =buffer[last]; + if ((c) != ' ' && (c) != '\r' && (c) != '\n') break; + } + last++; + if (last>prev_last) input_add_char(' '); +} + +static int input_command_line(void) +{@+ +last=first; +while (optind < argc) input_add_str(argv[optind++]); +loc=first; +return (loc < last); +@+ } + + + +@ When we open an output file, there is usually no searching necessary. +In the best case, we have an absolute path and can open it. +If the path is relative, we try in this order: +the |file_name| prefixed by the |output_directory|, +the |file_name| as is, and +the |file_name| prefixed with the environment variable |TEXMFOUTPUT|. + +If we were successful with one of the modified names, we update +|name_of_file|. + +@<k\TeX\ functions@>= +FILE *open_out(const char *file_name, const char *file_mode) +{@+ FILE *f=NULL; + char *new_name=NULL; + int absolute = kpse_absolute_p(file_name, false); + if (absolute) + return fopen(file_name,file_mode); + if (output_directory) + { new_name = concat3(output_directory, DIR_SEP_STRING, file_name); + f = fopen(new_name,file_mode); + if (f==NULL) {@+ free(new_name); new_name=NULL;@+} + } + if (f==NULL) + f = fopen(file_name,file_mode); + if (f==NULL) + { const char *texmfoutput = kpse_var_value("TEXMFOUTPUT"); + if (texmfoutput!=NULL && texmfoutput[0]!=0) + { new_name = concat3(texmfoutput, DIR_SEP_STRING, file_name);@/ + f = fopen(new_name,file_mode); + if (f==NULL) {@+ free(new_name); new_name=NULL; @+} + } + } + if (f!=NULL && new_name!=NULL) + update_name_of_file(new_name,(int)strlen(new_name)); + if (new_name!=NULL) free(new_name); + return f; +} + +static bool a_open_out(alpha_file *f) + /*open a text file for output*/ +{@+f->f=open_out((char*)name_of_file+1,"w"); + return f->f!=NULL && ferror(f->f)==0;@+ +} + +static bool b_open_out(byte_file *f) + /*open a binary file for output*/ +{@+f->f=open_out((char *)name_of_file+1,"wb"); +return f->f!=NULL && ferror(f->f)==0;@+ +} + +#ifdef @!INIT +static bool w_open_out(word_file *f) + /*open a word file for output*/ +{@+f->f=open_out((char *)name_of_file+1,"wb"); + return f->f!=NULL && ferror(f->f)==0;@+ +} +#endif + +@ Format file names must be scanned +before \TeX's string mechanism has been initialized. +The function |update_name_of_file| will set |name_of_file| from +a \CEE/ string. + +We dare not give error messages here, since \TeX\ calls this routine before +the |error| routine is ready to roll. Instead, we simply drop excess characters, +since the error will be detected in another way when a strange file name +isn't found. +@^system dependencies@> + +@<k\TeX\ auxiliar functions@>= +static void update_name_of_file(char *@!s, int @!k) +{@+ int j; + if (k <= file_name_size) name_length=k;@+ + else name_length=file_name_size; + for (j=0; j<name_length;j++) name_of_file[j+1]=xchr[(int)s[j]]; + name_of_file[name_length+1]=0; +} + +@ In standard \TeX, the |reset| macro is used to open input files. +The \.{kpathsearch} library uses different search pathes for +different types of files and therefore different functions are needed to +open these files. The common code is in the function |open_in|. + + +@<k\TeX\ auxiliar functions@>= +static FILE*open_in(char*filename,kpse_file_format_type t,const char*rwb) +{@+ char *fname=NULL; + FILE*f= NULL; + fname= find_file(filename,t,true); + if(fname!=NULL) + {@+ + f= fopen(fname,rwb); + free(fname);@+ + } + return f; +} + +@ @<k\TeX\ functions@>= +static bool a_open_in(alpha_file *f) /*open a text file for input*/ +{@+f->f= open_in((char *)name_of_file+1,kpse_tex_format,"r"); + if (f->f!=NULL) get(*f); + return f->f!=NULL && ferror(f->f)==0; +} + +static bool b_open_in(byte_file *f) /*open a binary file for input*/ +{@+f->f= kpse_open_file((char *)name_of_file+1,kpse_tfm_format); + if (f->f!=NULL) get(*f); + return f->f!=NULL && ferror(f->f)==0; +} + + +@ \TeX's |open_fmt_file| function will call the following function +either with the name of a format file as given with an ``\.{\AM}'' +prefix in the input or with |NULL| if no such name was specified. +The function will try |dump_name| as a last resort before returning |NULL|. + + + +@<k\TeX\ functions@>= +static bool w_open_in(word_file *f) /*open a word file for input*/ +{@+ + f->f=NULL; + if (name_of_file[1]!=0) + f->f= open_in((char*)name_of_file+1,kpse_fmt_format,"rb"); + if (f->f!=NULL) get(*f); + return f->f!=NULL && ferror(f->f)==0; +} + +static bool open_fmt_file(void) +{@+int j=loc; + if (buffer[loc]=='&') + {@+incr(loc);j=loc;buffer[last]=' '; + while (buffer[j]!=' ') incr(j); + update_name_of_file((char *)buffer+loc,j-loc); + if (w_open_in(&fmt_file)) goto found; + } + update_name_of_file(dump_name,(int)strlen(dump_name)); + if (w_open_in(&fmt_file)) goto found; + name_of_file[1]=0; + wake_up_terminal; + wterm_ln("I can't find a format file!"); + return false; +found: loc=j;return true; +} + + + +@ All the code that we have seen so far commes together in the function |main_init| +which is the first function called in the main program of a \TeX\ engine +belonging to \TeX\ Live. Before doing so, we make copies of +argument count and argument vector putting them in global variables. +@<Global...@>= +static char **argv; +static int argc; + +@ @<k\TeX\ functions@>= +static void main_init(int ac, char *av[]) +{@+ + char* main_input_file; + argc = ac; + argv = av; + interaction = error_stop_mode;@/ + @<parse options@>@; + @<set the program and engine name@>@; + @<activate configuration lines@>@; + @<set the input file name@>@; + @<set defaults from the {\tt texmf.cfg} file@>@; + @<set the format name@>@; + @<enable the generation of input files@>@; +} + + +@ Before we can call the |parse_options| function, +we might need some special preparations for Windows. + +@<parse options@>= +#if defined(WIN32) +{@+ char* enc; + kpse_set_program_name (argv[0], NULL); + enc = kpse_var_value("command_line_encoding"); + get_command_line_args_utf8(enc, &argc, &argv);@/ + parse_options (argc, argv); +} +#else + parse_options (ac, av); +#endif + +@ Adding prototypes for the functions just defined allows \TeX\ +to call them. + +@<Header files and function declarations@>= + +static int input_command_line(void); +static void main_init(int ac, char *av[]); + +@ We conclude this chapter using \.{time.h} to provide a function +that is used to initialize +\TeX's date and time information. Because |time| is one of \TeX's +macros, we add the function |tl_now| that wraps the call to |time| +(and |gmtime|) for later use in |fix_date_and_time|. + +@<Header files and function declarations@>= +#include <time.h> +static struct tm *tl_now(void) +{@+ time_t t=time(NULL); + return gmtime(&t); +} + + +@* Index. +Here is where you can find all uses of each identifier in the program, +with underlined entries pointing to where the identifier was defined. +If the identifier is only one letter long, however, you get to see only +the underlined entries. {\sl All references are to section numbers instead of +page numbers.} + +This index also lists error messages and other aspects of the program +that you might want to look up some day. For example, the entry +for ``system dependencies'' lists all sections that should receive +special attention from people who are installing \TeX\ in a new +operating environment. A list of various things that can't happen appears +under ``this can't happen''. Approximately 40 sections are listed under +``inner loop''; these account for about 60\pct! of \TeX's running time, +exclusive of input and output. + +@ Generating the header file. +@(htex.h@>= +@h +enum {@+@<Constants in the outer block@>@+}; +@<Types in the outer block@>@; +extern void display_node(pointer p); +extern void hyphenate_word(void); +extern memory_word *const hfactor_eqtb, *const vfactor_eqtb; +extern scaled par_shape_hfactor, par_shape_vfactor; +extern scaled hhsize, hvsize; +extern int option_no_empty_page, option_hyphen_first; +extern int option_dpi; +extern FILE *open_out(const char *file_name, const char *file_mode); +extern void update_last_values(pointer p); /* see section~\secref{pagebuilder} */ +extern void print_err(char *s); +extern int s_no(const char *str); +extern two_halves *const hash; +extern scaled *const font_dsize; +extern scaled *const font_size; +extern void end_diagnostic(bool @!blank_line); +extern void show_box(pointer @!p); +extern void begin_diagnostic(void); +extern void short_display(int @!p); +extern int font_in_short_display; +extern int line; +extern int pack_begin_line; +extern void print_scaled(scaled @!s); +extern pointer new_null_box(void); +extern pointer new_rule(void); +extern void print_int(int @!n); +extern halfword badness(scaled @!t, scaled @!s); +extern str_number job_name; +extern pointer adjust_tail; +extern int *const depth_base; +extern int *const height_base; +extern int *const width_base; +extern int *const char_base; +extern scaled *const total_shrink; +extern scaled *const total_stretch; +extern int last_badness; +extern int dyn_used; +extern list_state_record nest[]; +extern void append_to_vlist(pointer @!b); +extern int nest_ptr; +extern void freeze_page_specs(small_number @!s); +extern pointer cur_p; +extern int r_hyf; +extern int l_hyf; +extern ASCII_code cur_lang; +extern void init_trie(void); +extern bool trie_not_ready; +extern void ship_out(pointer @!p); +extern void scan_left_brace(void); +extern void normal_paragraph(void); +extern void new_save_level(group_code @!c); +extern void begin_token_list(pointer @!p, quarterword @!t); +extern void push_nest(void); +extern void pop_nest(void); +extern int init_r_hyf; +extern int init_l_hyf; +extern ASCII_code init_cur_lang; +extern void delete_glue_ref(pointer @!p); +extern pointer new_param_glue(small_number @!n); +extern pointer new_penalty(int @!m); +extern scaled second_indent; +extern scaled second_width; +extern halfword last_special_line; +extern void line_break(int @!final_widow_penalty); +extern list_state_record cur_list; +extern void show_node_list(int @!p); +extern int depth_threshold; +extern int breadth_max; +extern void print_ln(void); +extern void free_node(pointer @!p, halfword @!s); +extern void flush_node_list(pointer @!p); +extern packed_ASCII_code str_pool[]; +extern pool_pointer str_start[]; +extern str_number *const font_name; +extern pointer new_character(internal_font_number @!f, eight_bits @!c); +extern int *const hyphen_char; +extern void delete_token_ref(pointer @!p); +extern pointer *const cur_mark; +extern memory_word *const eqtb; +extern memory_word font_info[]; +extern int *const param_base; +extern pointer new_spec(pointer @!p); +extern pointer new_glue(pointer @!q); +extern unsigned char *const name_of_file; +extern pointer new_disc(void); +extern pointer *const font_glue; +extern pointer copy_node_list(pointer @!p); +extern pointer get_node(int @!s); +extern pointer hi_mem_min; +extern int name_length; +extern void out_what(pointer @!p); +extern bool doing_leaders; +extern bool output_active; +extern int interaction; +extern memory_word *const mem; +extern int page_contents; +extern scaled page_so_far[]; +extern void end_graf(void); +extern void unsave(void); +extern void open_log_file(void); +extern void print_char(ASCII_code @!s); +extern void prompt_file_name(char *@!s, char *@!e); +extern void pack_job_name(char *@!s); +extern void print_spec(int @!p, char *@!s); +extern void pack_file_name(str_number @!n, char *@!a, char *@!e); +extern void print(char *@!s); +extern void print_nl(char *@!s); +extern void fatal_error(char *@!s); +extern void overflow(char *@!s, int @!n); +extern void confusion(char *@!s); +extern int main(int argc, char *argv[]); diff --git a/Build/source/texk/web2c/hitexdir/lex.sed b/Build/source/texk/web2c/hitexdir/lex.sed new file mode 100644 index 00000000000..51ad4d6467a --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/lex.sed @@ -0,0 +1,5 @@ +/#line [0-9]\+/d +s/::\(.*\):<\(.*\)> :/\1\t\2/ +s/\/\*/\t\/\*/g +s/^<\([A-Z]\+\)> {/<\1>{/ + diff --git a/Build/source/texk/web2c/hitexdir/yacc.sed b/Build/source/texk/web2c/hitexdir/yacc.sed new file mode 100644 index 00000000000..4d3f6aac0f1 --- /dev/null +++ b/Build/source/texk/web2c/hitexdir/yacc.sed @@ -0,0 +1,3 @@ +/#line [0-9]\+/d +s/$<\([a-z]\)> \([0-9]\)/$<\1>\2/ + |