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-% This is etex.ch, a
-% WEB change file containing code for various features extending TeX;
-% to be applied to tex.web in order to define the
-% e-TeX program.
-
-% 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.
-
-% The TeX program is copyright (C) 1982 by D. E. Knuth.
-% TeX is a trademark of the American Mathematical Society.
-% e-TeX and NTS are trademarks of the NTS group.
-
-% All line numbers refer to tex.web 3.14159265 as of January 20, 2014.
-
-@x limbo l.1 - this is e-TeX
-% This program is copyright (C) 1982 by D. E. Knuth; all rights are reserved.
-% Unlimited copying and redistribution of this file are permitted as long
-% as this file is not modified. Modifications are permitted, but only if
-% the resulting file is not named tex.web. (The WEB system provides
-% for alterations via an auxiliary file; the master file should stay intact.)
-% See Appendix H of the WEB manual for hints on how to install this program.
-% And see Appendix A of the TRIP manual for details about how to validate it.
-
-% TeX is a trademark of the American Mathematical Society.
-% METAFONT is a trademark of Addison-Wesley Publishing Company.
-@y
-% 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.
-
-% e-TeX and NTS are trademarks of the NTS group.
-% TeX is a trademark of the American Mathematical Society.
-% METAFONT is a trademark of Addison-Wesley Publishing Company.
-
-% 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.
-@z
-%---------------------------------------
-@x limbo l.51 - e-TeX history
-% Although considerable effort has been expended to make the 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.
-@y
-% 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.
-@z
-%---------------------------------------
-@x limbo l.63 - e-TeX logo, TeXXeT
-\let\mc=\ninerm % medium caps for names like SAIL
-@y
-\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
-@z
-%---------------------------------------
-@x limbo l.66 - bug fix (print only changed modules)
-\def\pct!{{\char`\%}} % percent sign in ordinary text
-@y
-\def\pct!{{\char`\%}} % percent sign in ordinary text
-\def\grp{\.{\char'173...\char'175}}
-@z
-%---------------------------------------
-@x limbo l.82 - e-TeX basic
-\def\title{\TeX82}
-@y
-\def\title{\eTeX}
-% 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
-@z
-%---------------------------------------
-@x [1] m.1 l.93 - this is e-TeX
-This is \TeX, a document compiler intended to produce typesetting of high
-@y
-This is \eTeX, a program derived from and extending the capabilities of
-\TeX, a document compiler intended to produce typesetting of high
-@z
-%---------------------------------------
-@x [1] m.2 l.182 - e-TeX basic
-If this program is changed, the resulting system should not be called
-@y
-This program contains code for various features extending \TeX,
-therefore this program is called `\eTeX' and not
-@z
-%---------------------------------------
-@x [1] m.2 l.188 - e-TeX basic
-November 1984].
-@y
-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'.
-@z
-%---------------------------------------
-@x [1] m.2 l.190 - e-TeX basic
-@d banner=='This is TeX, Version 3.141592653' {printed when \TeX\ starts}
-@y
-@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 3.141592653',eTeX_version_string
- {printed when \eTeX\ starts}
-@#
-@d TeX_banner=='This is TeX, Version 3.141592653' {printed when \TeX\ starts}
-@#
-@d banner==eTeX_banner
-@#
-@d TEX==ETEX {change program name into |ETEX|}
-@#
-@d TeXXeT_code=0 {the \TeXXeT\ feature is optional}
-@#
-@d eTeX_states=1 {number of \eTeX\ state variables in |eqtb|}
-@z
-%---------------------------------------
-@x [1] m.3 l.209 - e-TeX basic
-scalar types; there are no `\&{var}' parameters, except in the case of files;
-@y
-scalar types; there are no `\&{var}' parameters, except in the case of files
---- \eTeX, however, does use `\&{var}' parameters for the |reverse| function;
-@z
-%---------------------------------------
-@x [1] m.15 l.504 - e-TeX basic
-@d not_found=45 {go here when you've found nothing}
-@y
-@d not_found=45 {go here when you've found nothing}
-@d not_found1=46 {like |not_found|, when there's more than one}
-@d not_found2=47 {like |not_found|, when there's more than two}
-@d not_found3=48 {like |not_found|, when there's more than three}
-@d not_found4=49 {like |not_found|, when there's more than four}
-@z
-%---------------------------------------
-@x [10] m.135 l.2895 - e-TeX TeXXeT
-|fil|, |fill|, or |filll|). The |subtype| field is not used.
-@y
-|fil|, |fill|, or |filll|). The |subtype| field is not used in \TeX.
-In \eTeX\ the |subtype| field records the box direction mode |box_lr|.
-@z
-%---------------------------------------
-@x [10] m.141 l.2980 - e-TeX marks
-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.
-@y
-In addition there is a |mark_class| field that contains the mark class.
-@z
-%---------------------------------------
-@x [10] m.141 l.2986 - e-TeX marks
-@d mark_ptr(#)==mem[#+1].int {head of the token list for a mark}
-@y
-@d mark_ptr(#)==link(#+1) {head of the token list for a mark}
-@d mark_class(#)==info(#+1) {the mark class}
-@z
-%---------------------------------------
-@x [10] m.142 l.2995 - e-TeX marks
-@d adjust_ptr==mark_ptr {vertical list to be moved out of horizontal list}
-@y
-@d adjust_ptr(#)==mem[#+1].int
- {vertical list to be moved out of horizontal list}
-@z
-%---------------------------------------
-@x [10] m.147 l.3084 - e-TeX TeXXeT
-the amount of surrounding space inserted by \.{\\mathsurround}.
-@y
-the amount of surrounding space inserted by \.{\\mathsurround}.
-
-In addition a |math_node| with |subtype>after| and |width=0| will be
-(ab)used to record a regular |math_node| reinserted after being
-discarded at a line break or one of the text direction primitives (
-\.{\\beginL}, \.{\\endL}, \.{\\beginR}, and \.{\\endR} ).
-@z
-%---------------------------------------
-@x [10] m.147 l.3088 - e-TeX TeXXeT
-@d after=1 {|subtype| for math node that winds up a formula}
-@y
-@d after=1 {|subtype| for math node that winds up a formula}
-@#
-@d M_code=2
-@d begin_M_code=M_code+before {|subtype| for \.{\\beginM} node}
-@d end_M_code=M_code+after {|subtype| for \.{\\endM} node}
-@d L_code=4
-@d begin_L_code=L_code+begin_M_code {|subtype| for \.{\\beginL} node}
-@d end_L_code=L_code+end_M_code {|subtype| for \.{\\endL} node}
-@d R_code=L_code+L_code
-@d begin_R_code=R_code+begin_M_code {|subtype| for \.{\\beginR} node}
-@d end_R_code=R_code+end_M_code {|subtype| for \.{\\endR} node}
-@#
-@d end_LR(#)==odd(subtype(#))
-@d end_LR_type(#)==(L_code*(subtype(#) div L_code)+end_M_code)
-@d begin_LR_type(#)==(#-after+before)
-@z
-%---------------------------------------
-@x [12] m.175 l.3561 - e-TeX TeXXeT
-math_node: print_char("$");
-@y
-math_node: if subtype(p)>=L_code then print("[]")
- else print_char("$");
-@z
-%---------------------------------------
-@x [12] m.184 l.3728 - e-TeX TeXXeT
- begin print(", shifted "); print_scaled(shift_amount(p));
- end;
-@y
- begin print(", shifted "); print_scaled(shift_amount(p));
- end;
- if eTeX_ex then @<Display if this box is never to be reversed@>;
-@z
-%---------------------------------------
-@x [12] m.192 l.3826 - e-TeX TeXXeT
-begin print_esc("math");
-@y
-if subtype(p)>after then
- begin if end_LR(p) then print_esc("end")
- else print_esc("begin");
- if subtype(p)>R_code then print_char("R")
- else if subtype(p)>L_code then print_char("L")
- else print_char("M");
- end else
-begin print_esc("math");
-@z
-%---------------------------------------
-@x [12] m.196 l.3859 - e-TeX marks
-begin print_esc("mark"); print_mark(mark_ptr(p));
-@y
-begin print_esc("mark");
-if mark_class(p)<>0 then
- begin print_char("s"); print_int(mark_class(p));
- end;
-print_mark(mark_ptr(p));
-@z
-%---------------------------------------
-@x [15] m.208 l.4096 - e-TeX saved_items
-@d un_vbox=24 {unglue a box ( \.{\\unvbox}, \.{\\unvcopy} )}
-@y
-@d un_vbox=24 {unglue a box ( \.{\\unvbox}, \.{\\unvcopy} )}
- {( or \.{\\pagediscards}, \.{\\splitdiscards} )}
-@z
-%---------------------------------------
-@x [15] m.208 l.4106 - e-TeX TeXXeT
-@d valign=33 {vertical table alignment ( \.{\\valign} )}
-@y
-@d valign=33 {vertical table alignment ( \.{\\valign} )}
- {or text direction directives ( \.{\\beginL}, etc.~)}
-@z
-%---------------------------------------
-@x [15] m.208 l.4122 - e-TeX middle
-@d left_right=49 {variable delimiter ( \.{\\left}, \.{\\right} )}
-@y
-@d left_right=49 {variable delimiter ( \.{\\left}, \.{\\right} )}
- {( or \.{\\middle} )}
-@z
-%---------------------------------------
-@x [15] m.209 l.4166 - e-TeX basic
- \.{\\insertpenalties} )}
-@y
- \.{\\insertpenalties} )}
- {( or \.{\\interactionmode} )}
-@z
-%---------------------------------------
-@x [15] m.209 l.4168 - e-TeX penalties
-@d set_shape=84 {specify fancy paragraph shape ( \.{\\parshape} )}
-@y
-@d set_shape=84 {specify fancy paragraph shape ( \.{\\parshape} )}
- {(or \.{\\interlinepenalties}, etc.~)}
-@z
-%---------------------------------------
-@x [15] m.209 l.4178 - e-TeX protected
-@d prefix=93 {qualify a definition ( \.{\\global}, \.{\\long}, \.{\\outer} )}
-@y
-@d prefix=93 {qualify a definition ( \.{\\global}, \.{\\long}, \.{\\outer} )}
- {( or \.{\\protected} )}
-@z
-%---------------------------------------
-@x [15] m.209 l.4181 - e-TeX read_line
-@d read_to_cs=96 {read into a control sequence ( \.{\\read} )}
-@y
-@d read_to_cs=96 {read into a control sequence ( \.{\\read} )}
- {( or \.{\\readline} )}
-@z
-%---------------------------------------
-@x [15] m.210 l.4196 - e-TeX scan_tokens
-@d input=max_command+4 {input a source file ( \.{\\input}, \.{\\endinput} )}
-@y
-@d input=max_command+4 {input a source file ( \.{\\input}, \.{\\endinput} )}
- {( or \.{\\scantokens} )}
-@z
-%---------------------------------------
-@x [15] m.210 l.4201 - e-TeX unexpanded
-@d the=max_command+9 {expand an internal quantity ( \.{\\the} )}
-@y
-@d the=max_command+9 {expand an internal quantity ( \.{\\the} )}
- {( or \.{\\unexpanded}, \.{\\detokenize} )}
-@z
-%---------------------------------------
-@x [16] m.212 l.4304 - e-TeX basic
-user's output routine.
-@y
-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|.
-@z
-%---------------------------------------
-@x [16] m.212 l.4319 - e-TeX basic
- @!head_field,@!tail_field: pointer;
-@y
- @!head_field,@!tail_field: pointer;
- @!eTeX_aux_field: pointer;
-@z
-%---------------------------------------
-@x [16] m.213 l.4326 - e-TeX basic
-@d tail==cur_list.tail_field {final node on current list}
-@y
-@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}
-@z
-%---------------------------------------
-@x [16] m.215 l.4357 - e-TeX basic
-mode:=vmode; head:=contrib_head; tail:=contrib_head;
-@y
-mode:=vmode; head:=contrib_head; tail:=contrib_head;
-eTeX_aux:=null;
-@z
-%---------------------------------------
-@x [16] m.216 l.4373 push_nest - e-TeX basic
-incr(nest_ptr); head:=get_avail; tail:=head; prev_graf:=0; mode_line:=line;
-@y
-incr(nest_ptr); head:=get_avail; tail:=head; prev_graf:=0; mode_line:=line;
-eTeX_aux:=null;
-@z
-%---------------------------------------
-@x [17] m.230 l.4736 - e-TeX basic, every_eof
-@d toks_base=local_base+10 {table of 256 token list registers}
-@y
-@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}
-@z
-%---------------------------------------
-@x [17] m.230 l.4737 - e-TeX basic, penalties
-@d box_base=toks_base+256 {table of 256 box registers}
-@y
-@#
-@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}
-@z
-%---------------------------------------
-@x [17] m.231 l.4802 - e-TeX basic
- othercases print_esc("errhelp")
-@y
- @/@<Cases of |assign_toks| for |print_cmd_chr|@>@/
- othercases print_esc("errhelp")
-@z
-%---------------------------------------
-@x [17] m.232 l.4820 - e-TeX penalties
-eq_level(par_shape_loc):=level_one;@/
-@y
-eq_level(par_shape_loc):=level_one;@/
-for k:=etex_pen_base to etex_pens-1 do
- eqtb[k]:=eqtb[par_shape_loc];
-@z
-%---------------------------------------
-@x [17] m.233 l.4848 - e-TeX penalties
-if n=par_shape_loc then
- begin print_esc("parshape"); print_char("=");
- if par_shape_ptr=null then print_char("0")
-@y
-if (n=par_shape_loc) or ((n>=etex_pen_base) and (n<etex_pens)) then
- begin print_cmd_chr(set_shape,n); print_char("=");
- if equiv(n)=null then print_char("0")
- else if n>par_shape_loc then
- begin print_int(penalty(equiv(n))); print_char(" ");
- print_int(penalty(equiv(n)+1));
- if penalty(equiv(n))>1 then print_esc("ETC.");
- end
-@z
-%---------------------------------------
-@x [17] m.236 l.4969 - e-TeX basic
-@d int_pars=55 {total number of integer parameters}
-@y
-@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 pre_display_direction_code=etex_int_base+5 {text direction preceding a display}
-@d last_line_fit_code=etex_int_base+6 {adjustment for last line of paragraph}
-@d saving_vdiscards_code=etex_int_base+7 {save items discarded from vlists}
-@d saving_hyph_codes_code=etex_int_base+8 {save hyphenation codes for languages}
-@d eTeX_state_code=etex_int_base+9 {\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}
-@z
-%---------------------------------------
-@x [17] m.236 l.5031 - e-TeX basic
-@d error_context_lines==int_par(error_context_lines_code)
-@y
-@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)
-@d pre_display_direction==int_par(pre_display_direction_code)
-@d last_line_fit==int_par(last_line_fit_code)
-@d saving_vdiscards==int_par(saving_vdiscards_code)
-@d saving_hyph_codes==int_par(saving_hyph_codes_code)
-@z
-%---------------------------------------
-@x [17] m.237 l.5096 print_param - e-TeX basic
-othercases print("[unknown integer parameter!]")
-@y
-@/@<Cases for |print_param|@>@/
-othercases print("[unknown integer parameter!]")
-@z
-%---------------------------------------
-@x [18] m.264 l.5627 primitive - e-TeX basic
-@!j:small_number; {index into |buffer|}
-@y
-@!j:0..buf_size; {index into |buffer|}
-@z
-%---------------------------------------
-@x [18] m.264 l.5631 primitive - e-TeX basic
- {we will move |s| into the (empty) |buffer|}
- for j:=0 to l-1 do buffer[j]:=so(str_pool[k+j]);
- cur_val:=id_lookup(0,l); {|no_new_control_sequence| is |false|}
-@y
- {we will move |s| into the (possibly non-empty) |buffer|}
- if first+l>buf_size+1 then
- overflow("buffer size",buf_size);
-@:TeX capacity exceeded buffer size}{\quad buffer size@>
- for j:=0 to l-1 do buffer[first+j]:=so(str_pool[k+j]);
- cur_val:=id_lookup(first,l); {|no_new_control_sequence| is |false|}
-@z
-%---------------------------------------
-@x [18] m.265 l.5706 - e-TeX penalties
-primitive("parshape",set_shape,0);@/
-@y
-primitive("parshape",set_shape,par_shape_loc);@/
-@z
-%---------------------------------------
-@x [18] m.265 l.5723 - e-TeX sparse arrays
-primitive("toks",toks_register,0);@/
-@y
-primitive("toks",toks_register,mem_bot);@/
-@z
-%---------------------------------------
-@x [18] m.266 l.5756 - e-TeX cond
-expand_after: print_esc("expandafter");
-@y
-expand_after: if chr_code=0 then print_esc("expandafter")
- @<Cases of |expandafter| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [18] m.266 l.5762 - e-TeX marks
-mark: print_esc("mark");
-@y
-mark: begin print_esc("mark");
- if chr_code>0 then print_char("s");
- end;
-@z
-%---------------------------------------
-@x [18] m.266 l.5773 - e-TeX read_line
-read_to_cs: print_esc("read");
-@y
-read_to_cs: if chr_code=0 then print_esc("read")
- @<Cases of |read| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [18] m.266 l.5777 - e-TeX penalties
-set_shape: print_esc("parshape");
-@y
-set_shape: case chr_code of
- par_shape_loc: print_esc("parshape");
- @<Cases of |set_shape| for |print_cmd_chr|@>@;@/
- end; {there are no other cases}
-@z
-%---------------------------------------
-@x [18] m.266 l.5778 - e-TeX unexpanded
-the: print_esc("the");
-@y
-the: if chr_code=0 then print_esc("the")
- @<Cases of |the| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [18] m.266 l.5779 - e-TeX sparse arrays
-toks_register: print_esc("toks");
-@y
-toks_register: @<Cases of |toks_register| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [18] m.266 l.5781 - e-TeX TeXXeT
-valign: print_esc("valign");
-@y
-valign: if chr_code=0 then print_esc("valign")@/
- @<Cases of |valign| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [19] m.268 l.5815 - e-TeX sparse arrays
-interpreted in one of four ways:
-@y
-interpreted in one of five ways:
-@z
-%---------------------------------------
-@x [19] m.268 l.5835 - e-TeX tracing
-the entries for that group.
-@y
-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.
-@z
-%---------------------------------------
-@x [19] m.268 l.5845 - e-TeX basic
-@d level_boundary=3 {|save_type| corresponding to beginning of group}
-@y
-@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@>
-@z
-%---------------------------------------
-@x [19] m.273 l.5903 - e-TeX tracing
-@ The following macro is used to test if there is room for up to six more
-@y
-@ The following macro is used to test if there is room for up to seven more
-@z
-%---------------------------------------
-@x [19] m.273 l.5909 check_full_save_stack - e-TeX tracing
- if max_save_stack>save_size-6 then overflow("save size",save_size);
-@y
- if max_save_stack>save_size-7 then overflow("save size",save_size);
-@z
-%---------------------------------------
-@x [19] m.274 l.5931 new_save_level - e-TeX tracing
-begin check_full_save_stack;
-@y
-begin check_full_save_stack;
-if eTeX_ex then
- begin saved(0):=line; incr(save_ptr);
- end;
-@z
-%---------------------------------------
-@x [19] m.274 l.5938 new_save_level - e-TeX tracing
-cur_boundary:=save_ptr; incr(cur_level); incr(save_ptr); cur_group:=c;
-@y
-cur_boundary:=save_ptr; cur_group:=c;
-@!stat if tracing_groups>0 then group_trace(false);@+tats@;@/
-incr(cur_level); incr(save_ptr);
-@z
-%---------------------------------------
-@x [19] m.275 l.5956 eq_destroy - e-TeX sparse arrays
-othercases do_nothing
-@y
-@/@<Cases for |eq_destroy|@>@/
-othercases do_nothing
-@z
-%---------------------------------------
-@x [19] m.277 l.5978 - e-TeX tracing
-the call, since |eq_save| makes the necessary test.
-@y
-the call, since |eq_save| makes the necessary test.
-
-@d assign_trace(#)==@!stat if tracing_assigns>0 then restore_trace(#);
- tats
-@z
-%---------------------------------------
-@x [19] m.277 l.5982 eq_define - e-TeX tracing
-begin if eq_level(p)=cur_level then eq_destroy(eqtb[p])
-@y
-label exit;
-begin if eTeX_ex and(eq_type(p)=t)and(equiv(p)=e) then
- begin assign_trace(p,"reassigning")@;@/
- eq_destroy(eqtb[p]); return;
- end;
-assign_trace(p,"changing")@;@/
-if eq_level(p)=cur_level then eq_destroy(eqtb[p])
-@z
-%---------------------------------------
-@x [19] m.277 l.5985 eq_define - e-TeX tracing
-end;
-@y
-assign_trace(p,"into")@;@/
-exit:end;
-@z
-%---------------------------------------
-@x [19] m.278 l.5992 eq_word_define - e-TeX tracing
-begin if xeq_level[p]<>cur_level then
-@y
-label exit;
-begin if eTeX_ex and(eqtb[p].int=w) then
- begin assign_trace(p,"reassigning")@;@/
- return;
- end;
-assign_trace(p,"changing")@;@/
-if xeq_level[p]<>cur_level then
-@z
-%---------------------------------------
-@x [19] m.278 l.5996 eq_word_define - e-TeX tracing
-end;
-@y
-assign_trace(p,"into")@;@/
-exit:end;
-@z
-%---------------------------------------
-@x [19] m.279 l.6005 geq_define - e-TeX tracing
-begin eq_destroy(eqtb[p]);
-eq_level(p):=level_one; eq_type(p):=t; equiv(p):=e;
-@y
-begin assign_trace(p,"globally changing")@;@/
-begin eq_destroy(eqtb[p]);
-eq_level(p):=level_one; eq_type(p):=t; equiv(p):=e;
-end;
-assign_trace(p,"into")@;@/
-@z
-%---------------------------------------
-@x [19] m.279 l.6010 geq_word_define - e-TeX tracing
-begin eqtb[p].int:=w; xeq_level[p]:=level_one;
-@y
-begin assign_trace(p,"globally changing")@;@/
-begin eqtb[p].int:=w; xeq_level[p]:=level_one;
-end;
-assign_trace(p,"into")@;@/
-@z
-%---------------------------------------
-@x [19] m.281 l.6027 - e-TeX tracing
-@p@t\4@>@<Declare the procedure called |restore_trace|@>@;@/
-@y
-@p
-@z
-%---------------------------------------
-@x [19] m.281 l.6034 unsave - e-TeX optimized \aftergroup
-begin if cur_level>level_one then
-@y
-@!a:boolean; {have we already processed an \.{\\aftergroup} ?}
-begin a:=false;
-if cur_level>level_one then
-@z
-%---------------------------------------
-@x [19] m.282 l.6048 - e-TeX sparse arrays
- else begin if save_type(save_ptr)=restore_old_value then
-@y
- else if save_type(save_ptr)=restore_sa then
- begin sa_restore; sa_chain:=p; sa_level:=save_level(save_ptr);
- end
- else begin if save_type(save_ptr)=restore_old_value then
-@z
-%---------------------------------------
-@x [19] m.282 l.6056 - e-TeX tracing
-done: cur_group:=save_level(save_ptr); cur_boundary:=save_index(save_ptr)
-@y
-done: @!stat if tracing_groups>0 then group_trace(true);@+tats@;@/
-if grp_stack[in_open]=cur_boundary then group_warning;
- {groups possibly not properly nested with files}
-cur_group:=save_level(save_ptr); cur_boundary:=save_index(save_ptr);
-if eTeX_ex then decr(save_ptr)
-@z
-%---------------------------------------
-@x [19] m.284 l.6082 - e-TeX tracing
-@ @<Declare the procedure called |restore_trace|@>=
-@y
-@ @<Declare \eTeX\ procedures for tr...@>=
-@z
-%---------------------------------------
-@x [20] m.289 l.6170 - e-TeX protected
-@d end_match_token=@'7000 {$2^8\cdot|end_match|$}
-@y
-@d end_match_token=@'7000 {$2^8\cdot|end_match|$}
-@d protected_token=@'7001 {$2^8\cdot|end_match|+1$}
-@z
-%---------------------------------------
-@x [20] m.294 l.6295 - e-TeX protected
-end_match: print("->");
-@y
-end_match: if c=0 then print("->");
-@z
-%---------------------------------------
-@x [20] m.296 l.6316 print_meaning - e-TeX marks
-else if cur_cmd=top_bot_mark then
-@y
-else if (cur_cmd=top_bot_mark)and(cur_chr<marks_code) then
-@z
-%---------------------------------------
-@x [21] m.298 l.6390 print_cmd_chr - e-TeX protected
-procedure print_cmd_chr(@!cmd:quarterword;@!chr_code:halfword);
-@y
-procedure print_cmd_chr(@!cmd:quarterword;@!chr_code:halfword);
-var n:integer; {temp variable}
-@z
-%---------------------------------------
-@x [21] m.299 l.6409 show_cur_cmd_chr - e-TeX tracing
-@p procedure show_cur_cmd_chr;
-@y
-@p procedure show_cur_cmd_chr;
-var n:integer; {level of \.{\\if...\\fi} nesting}
-@!l:integer; {line where \.{\\if} started}
-@!p:pointer;
-@z
-%---------------------------------------
-@x [21] m.299 l.6414 show_cur_cmd_chr - e-TeX tracing
-print_cmd_chr(cur_cmd,cur_chr); print_char("}");
-@y
-print_cmd_chr(cur_cmd,cur_chr);
-if tracing_ifs>0 then
- if cur_cmd>=if_test then if cur_cmd<=fi_or_else then
- begin print(": ");
- if cur_cmd=fi_or_else then
- begin print_cmd_chr(if_test,cur_if); print_char(" ");
- n:=0; l:=if_line;
- end
- else begin n:=1; l:=line;
- end;
- p:=cond_ptr;
- while p<>null do
- begin incr(n); p:=link(p);
- end;
- print("(level "); print_int(n); print_char(")"); print_if_line(l);
- end;
-print_char("}");
-@z
-%---------------------------------------
-@x [22] m.303 l.6490 show_context - e-TeX scan_tokens
-the terminal, under control of the procedure |read_toks|.)
-@y
-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.
-@z
-%---------------------------------------
-@x [22] m.307 l.6687 - e-TeX basic, every_eof
-only if |token_type>=macro|.
-@^reference counts@>
-@y
-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|.
-@z
-%---------------------------------------
-@x [22] m.307 l.6708 - e-TeX basic
-@d write_text=15 {|token_type| code for \.{\\write}}
-@y
-@#
-@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}}
-@z
-%---------------------------------------
-@x [22] m.311 l.6764 show_context - e-TeX scan_tokens
- if (name>17) or (base_ptr=0) then bottom_line:=true;
-@y
- if (name>19) or (base_ptr=0) then bottom_line:=true;
-@z
-%---------------------------------------
-@x [22] m.313 l.6809 - e-TeX scan_tokens
-else begin print_nl("l."); print_int(line);
-@y
-else begin print_nl("l.");
- if index=in_open then print_int(line)
- else print_int(line_stack[index+1]); {input from a pseudo file}
-@z
-%---------------------------------------
-@x [22] m.314 l.6831 - e-TeX basic
-write_text: print_nl("<write> ");
-@y
-every_eof_text: print_nl("<everyeof> ");
-write_text: print_nl("<write> ");
-@z
-%---------------------------------------
-@x [23] m.326 l.7024 - e-TeX optimized \aftergroup
-begin t:=cur_tok; cur_tok:=p; back_input; cur_tok:=t;
-@y
-begin t:=cur_tok; cur_tok:=p;
-if a then
- begin p:=get_avail; info(p):=cur_tok; link(p):=loc; loc:=p; start:=p;
- if cur_tok<right_brace_limit then
- if cur_tok<left_brace_limit then decr(align_state)
- else incr(align_state);
- end
-else begin back_input; a:=eTeX_ex;
- end;
-cur_tok:=t;
-@z
-%---------------------------------------
-@x [23] m.328 l.7052 begin_file_reading - e-TeX every_eof, tracing_nesting
-incr(in_open); push_input; index:=in_open;
-@y
-incr(in_open); push_input; index:=in_open;
-eof_seen[index]:=false;
-grp_stack[index]:=cur_boundary; if_stack[index]:=cond_ptr;
-@z
-%---------------------------------------
-@x [23] m.329 l.7062 end_file_reading - e-TeX scan_tokens
-if name>17 then a_close(cur_file); {forget it}
-@y
-if (name=18)or(name=19) then pseudo_close else
-if name>17 then a_close(cur_file); {forget it}
-@z
-%---------------------------------------
-@x [23] m.331 l.7081 - e-TeX tracing_nesting
-in_open:=0; open_parens:=0; max_buf_stack:=0;
-@y
-in_open:=0; open_parens:=0; max_buf_stack:=0;
-grp_stack[0]:=0; if_stack[0]:=null;
-@z
-%---------------------------------------
-@x [24] m.362 l.7553 - e-TeX scan_tokens, every_eof
-if not force_eof then
-@y
-if not force_eof then
- if name<=19 then
- begin if pseudo_input then {not end of file}
- firm_up_the_line {this sets |limit|}
- else if (every_eof<>null)and not eof_seen[index] then
- begin limit:=first-1; eof_seen[index]:=true; {fake one empty line}
- begin_token_list(every_eof,every_eof_text); goto restart;
- end
- else force_eof:=true;
- end
- else
-@z
-%---------------------------------------
-@x [24] m.362 l.7556 - e-TeX every_eof
- else force_eof:=true;
-@y
- else if (every_eof<>null)and not eof_seen[index] then
- begin limit:=first-1; eof_seen[index]:=true; {fake one empty line}
- begin_token_list(every_eof,every_eof_text); goto restart;
- end
- else force_eof:=true;
-@z
-%---------------------------------------
-@x [24] m.362 l.7559 - e-TeX scan_tokens
- begin print_char(")"); decr(open_parens);
- update_terminal; {show user that file has been read}
-@y
- begin if tracing_nesting>0 then
- if (grp_stack[in_open]<>cur_boundary)or@|
- (if_stack[in_open]<>cond_ptr) then file_warning;
- {give warning for some unfinished groups and/or conditionals}
- if name>=19 then
- begin print_char(")"); decr(open_parens);
- update_terminal; {show user that file has been read}
- end;
-@z
-%---------------------------------------
-@x [25] m.366 l.7643 - e-TeX basic
-@t\4@>@<Declare the procedure called |insert_relax|@>@;@/
-@y
-@t\4@>@<Declare the procedure called |insert_relax|@>@;@/
-@t\4@>@<Declare \eTeX\ procedures for expanding@>@;@/
-@z
-%---------------------------------------
-@x [25] m.366 l.7650 expand - e-TeX cond
-procedure expand;
-@y
-procedure expand;
-label reswitch;
-@z
-%---------------------------------------
-@x [25] m.366 l.7661 expand - e-TeX cond
-if cur_cmd<call then @<Expand a nonmacro@>
-@y
-reswitch:
-if cur_cmd<call then @<Expand a nonmacro@>
-@z
-%---------------------------------------
-@x [25] m.367 l.7672 - e-TeX cond
-expand_after:@<Expand the token after the next token@>;
-@y
-expand_after:if cur_chr=0 then @<Expand the token after the next token@>
- else @<Negate a boolean conditional and |goto reswitch|@>;
-@z
-%---------------------------------------
-@x [25] m.377 l.7792 - e-TeX scan_tokens
-input: if chr_code=0 then print_esc("input")@+else print_esc("endinput");
-@y
-input: if chr_code=0 then print_esc("input")
- @/@<Cases of |input| for |print_cmd_chr|@>@/
- else print_esc("endinput");
-@z
-%---------------------------------------
-@x [25] m.378 l.7795 - e-TeX scan_tokens
-if cur_chr>0 then force_eof:=true
-@y
-if cur_chr=1 then force_eof:=true
-@/@<Cases for |input|@>@/
-@z
-%---------------------------------------
-@x [25] m.382 l.7851 - e-TeX marks
-@d top_mark_code=0 {the mark in effect at the previous page break}
-@y
-@d marks_code==5 {add this for \.{\\topmarks} etc.}
-@#
-@d top_mark_code=0 {the mark in effect at the previous page break}
-@z
-%---------------------------------------
-@x [25] m.385 l.7883 - e-TeX marks
-top_bot_mark: case chr_code of
-@y
-top_bot_mark: begin case (chr_code mod marks_code) of
-@z
-%---------------------------------------
-@x [25] m.385 l.7889 - e-TeX marks
- endcases;
-@y
- endcases;
- if chr_code>=marks_code then print_char("s");
- end;
-@z
-%---------------------------------------
-@x [25] m.386 l.7895 - e-TeX marks
-begin if cur_mark[cur_chr]<>null then
- begin_token_list(cur_mark[cur_chr],mark_text);
-@y
-begin t:=cur_chr mod marks_code;
-if cur_chr>=marks_code then scan_register_num@+else cur_val:=0;
-if cur_val=0 then cur_ptr:=cur_mark[t]
-else @<Compute the mark pointer for mark type |t| and class |cur_val|@>;
-if cur_ptr<>null then begin_token_list(cur_ptr,mark_text);
-@z
-%---------------------------------------
-@x [25] m.389 l.7958 macro_call - e-TeX protected
-if info(r)<>end_match_token then
-@y
-if info(r)=protected_token then r:=link(r);
-if info(r)<>end_match_token then
-@z
-%---------------------------------------
-@x [26] m.409 l.8270 - e-TeX basic
-@t\4\4@>@<Declare procedures that scan font-related stuff@>
-@y
-@t\4\4@>@<Declare \eTeX\ procedures for scanning@>@;
-@t\4\4@>@<Declare procedures that scan font-related stuff@>
-@z
-%---------------------------------------
-@x [26] m.411 l.8314 - e-TeX sparse arrays
-|glue_val|, or |mu_val|.
-@y
-|glue_val|, or |mu_val| more than |mem_bot| (dynamic variable-size nodes
-cannot have these values)
-@z
-%---------------------------------------
-@x [26] m.411 l.8317 - e-TeX sparse arrays
-primitive("count",register,int_val);
-@!@:count_}{\.{\\count} primitive@>
-primitive("dimen",register,dimen_val);
-@!@:dimen_}{\.{\\dimen} primitive@>
-primitive("skip",register,glue_val);
-@!@:skip_}{\.{\\skip} primitive@>
-primitive("muskip",register,mu_val);
-@y
-primitive("count",register,mem_bot+int_val);
-@!@:count_}{\.{\\count} primitive@>
-primitive("dimen",register,mem_bot+dimen_val);
-@!@:dimen_}{\.{\\dimen} primitive@>
-primitive("skip",register,mem_bot+glue_val);
-@!@:skip_}{\.{\\skip} primitive@>
-primitive("muskip",register,mem_bot+mu_val);
-@z
-%---------------------------------------
-@x [26] m.412 l.8327 - e-TeX sparse arrays
-register: if chr_code=int_val then print_esc("count")
- else if chr_code=dimen_val then print_esc("dimen")
- else if chr_code=glue_val then print_esc("skip")
- else print_esc("muskip");
-@y
-register: @<Cases of |register| for |print_cmd_chr|@>;
-@z
-%---------------------------------------
-@x [26] m.413 l.8343 scan_something_internal - e-TeX basic
-var m:halfword; {|chr_code| part of the operand token}
-@y
-label exit;
-var m:halfword; {|chr_code| part of the operand token}
-@!q,@!r:pointer; {general purpose indices}
-@!tx:pointer; {effective tail node}
-@!i:four_quarters; {character info}
-@z
-%---------------------------------------
-@x [26] m.413 l.8369 scan_something_internal - e-TeX basic
-end;
-@y
-exit:end;
-@z
-%---------------------------------------
-@x [26] m.415 l.8390 - e-TeX sparse arrays
- begin scan_eight_bit_int; m:=toks_base+cur_val;
- end;
- scanned_result(equiv(m))(tok_val);
-@y
- if m=mem_bot then
- begin scan_register_num;
- if cur_val<256 then cur_val:=equiv(toks_base+cur_val)
- else begin find_sa_element(tok_val,cur_val,false);
- if cur_ptr=null then cur_val:=null
- else cur_val:=sa_ptr(cur_ptr);
- end;
- end
- else cur_val:=sa_ptr(m)
- else cur_val:=equiv(m);
- cur_val_level:=tok_val;
-@z
-%---------------------------------------
-@x [26] m.416 l.8405 - e-TeX basic
-|glue_val|, |input_line_no_code|, or |badness_code|.
-@y
-|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\ .
-@z
-%---------------------------------------
-@x [26] m.416 l.8407 - e-TeX basic
-@d input_line_no_code=glue_val+1 {code for \.{\\inputlineno}}
-@d badness_code=glue_val+2 {code for \.{\\badness}}
-@y
-@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}
-@z
-%---------------------------------------
-@x [26] m.417 l.8440 - e-TeX interaction_mode
-@+else print_esc("insertpenalties");
-@y
-@/@<Cases of |set_page_int| for |print_cmd_chr|@>@/
-@+else print_esc("insertpenalties");
-@z
-%---------------------------------------
-@x [26] m.417 l.8449 - e-TeX basic
- othercases print_esc("badness")
-@y
- @/@<Cases of |last_item| for |print_cmd_chr|@>@/
- othercases print_esc("badness")
-@z
-%---------------------------------------
-@x [26] m.419 l.8469 - e-TeX interaction_mode
-begin if m=0 then cur_val:=dead_cycles@+else cur_val:=insert_penalties;
-@y
-begin if m=0 then cur_val:=dead_cycles
-@/@<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>@/
-else cur_val:=insert_penalties;
-@z
-%---------------------------------------
-@x [26] m.420 l.8474 - e-TeX sparse arrays
-begin scan_eight_bit_int;
-if box(cur_val)=null then cur_val:=0 @+else cur_val:=mem[box(cur_val)+m].sc;
-@y
-begin scan_register_num; fetch_box(q);
-if q=null then cur_val:=0 @+else cur_val:=mem[q+m].sc;
-@z
-%---------------------------------------
-@x [26] m.423 l.8499 - e-TeX penalties
-begin if par_shape_ptr=null then cur_val:=0
-@y
-begin if m>par_shape_loc then @<Fetch a penalties array element@>
-else if par_shape_ptr=null then cur_val:=0
-@z
-%---------------------------------------
-@x [26] m.424 l.8504 - e-TeX \lastnodetype
-@ Here is where \.{\\lastpenalty}, \.{\\lastkern}, and \.{\\lastskip} are
-@y
-@ Here is where \.{\\lastpenalty}, \.{\\lastkern}, \.{\\lastskip}, and
-\.{\\lastnodetype} are
-@z
-%---------------------------------------
-@x [26] m.424 l.8508 - e-TeX TeXXeT
-legal in similar contexts.
-@y
-legal in similar contexts.
-
-The macro |find_effective_tail_eTeX| sets |tx| to the last non-\.{\\endM}
-node of the current list.
-@z
-%---------------------------------------
-@x [26] m.424 l.8510 - e-TeX TeXXeT
-@<Fetch an item in the current node...@>=
-@y
-@d find_effective_tail_eTeX==
-tx:=tail;
-if not is_char_node(tx) then
- if (type(tx)=math_node)and(subtype(tx)=end_M_code) then
- begin r:=head;
- repeat q:=r; r:=link(q);
- until r=tx;
- tx:=q;
- end
-@#
-@d find_effective_tail==find_effective_tail_eTeX
-
-@<Fetch an item in the current node...@>=
-@z
-%---------------------------------------
-@x [26] m.424 l.8511 - e-TeX basic
-if cur_chr>glue_val then
-@y
-if m>=input_line_no_code then
-@z
-%---------------------------------------
-@x [26] m.424 l.8512 - e-TeX basic
- begin if cur_chr=input_line_no_code then cur_val:=line
- else cur_val:=last_badness; {|cur_chr=badness_code|}
-@y
- if m>=eTeX_glue then @<Process an expression and |return|@>@;
- else if m>=eTeX_dim then
- begin case m of
- @/@<Cases for fetching a dimension value@>@/
- end; {there are no other cases}
- cur_val_level:=dimen_val;
- end
- else begin case m of
- input_line_no_code: cur_val:=line;
- badness_code: cur_val:=last_badness;
- @/@<Cases for fetching an integer value@>@/
- end; {there are no other cases}
-@z
-%---------------------------------------
-@x [26] m.424 l.8517 - e-TeX last_node_type
- cur_val_level:=cur_chr;
- if not is_char_node(tail)and(mode<>0) then
- case cur_chr of
- int_val: if type(tail)=penalty_node then cur_val:=penalty(tail);
- dimen_val: if type(tail)=kern_node then cur_val:=width(tail);
- glue_val: if type(tail)=glue_node then
- begin cur_val:=glue_ptr(tail);
- if subtype(tail)=mu_glue then cur_val_level:=mu_val;
- end;
- end {there are no other cases}
- else if (mode=vmode)and(tail=head) then
-@y
- find_effective_tail;
- if cur_chr=last_node_type_code then
- begin cur_val_level:=int_val;
- if (tx=head)or(mode=0) then cur_val:=-1;
- end
- else cur_val_level:=cur_chr;
- if not is_char_node(tx)and(mode<>0) then
- case cur_chr of
- int_val: if type(tx)=penalty_node then cur_val:=penalty(tx);
- dimen_val: if type(tx)=kern_node then cur_val:=width(tx);
- glue_val: if type(tx)=glue_node then
- begin cur_val:=glue_ptr(tx);
- if subtype(tx)=mu_glue then cur_val_level:=mu_val;
- end;
- last_node_type_code: if type(tx)<=unset_node then cur_val:=type(tx)+1
- else cur_val:=unset_node+2;
- end {there are no other cases}
- else if (mode=vmode)and(tx=head) then
-@z
-%---------------------------------------
-@x [26] m.424 l.8531 - e-TeX last_node_type
- glue_val: if last_glue<>max_halfword then cur_val:=last_glue;
-@y
- glue_val: if last_glue<>max_halfword then cur_val:=last_glue;
- last_node_type_code: cur_val:=last_node_type;
-@z
-%---------------------------------------
-@x [26] m.427 l.8547 - e-TeX sparse arrays
-begin scan_eight_bit_int;
-case m of
-@y
-begin if (m<mem_bot)or(m>lo_mem_stat_max) then
- begin cur_val_level:=sa_type(m);
- if cur_val_level<glue_val then cur_val:=sa_int(m)
- else cur_val:=sa_ptr(m);
- end
-else begin scan_register_num; cur_val_level:=m-mem_bot;
- if cur_val>255 then
- begin find_sa_element(cur_val_level,cur_val,false);
- if cur_ptr=null then
- if cur_val_level<glue_val then cur_val:=0
- else cur_val:=zero_glue
- else if cur_val_level<glue_val then cur_val:=sa_int(cur_ptr)
- else cur_val:=sa_ptr(cur_ptr);
- end
- else
- case cur_val_level of
-@z
-%---------------------------------------
-@x [26] m.427 l.8554 - e-TeX sparse arrays
-cur_val_level:=m;
-@y
- end;
-@z
-%---------------------------------------
-@x [26] m.461 l.9082 - e-TeX expr
-exit:end;
-@y
-exit:end;
-@#
-@<Declare procedures needed for expressions@>@;
-@z
-%---------------------------------------
-@x [27] m.464 l.9141 - e-TeX basic
-@p function str_toks(@!b:pool_pointer):pointer;
-@y
-@p @t\4@>@<Declare \eTeX\ procedures for token lists@>@;@/
-function str_toks(@!b:pool_pointer):pointer;
-@z
-%---------------------------------------
-@x [27] m.465 l.9166 the_toks - e-TeX unexpanded
-@p function the_toks:pointer;
-@y
-@p function the_toks:pointer;
-label exit;
-@z
-%---------------------------------------
-@x [27] m.465 l.9170 the_toks - e-TeX unexpanded
-begin get_x_token; scan_something_internal(tok_val,false);
-@y
-@!c:small_number; {value of |cur_chr|}
-begin @<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>;@/
-get_x_token; scan_something_internal(tok_val,false);
-@z
-%---------------------------------------
-@x [27] m.465 l.9184 the_toks - e-TeX unexpanded
-end;
-@y
-exit:end;
-@z
-%---------------------------------------
-@x [27] m.468 l.9207 - e-TeX basic
-@d number_code=0 {command code for \.{\\number}}
-@y
-\eTeX\ adds \.{\\eTeXrevision} such that |job_name_code| remains last.
-
-@d number_code=0 {command code for \.{\\number}}
-@z
-%---------------------------------------
-@x [27] m.468 l.9212 - e-TeX basic
-@d job_name_code=5 {command code for \.{\\jobname}}
-@y
-@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}}
-@z
-%---------------------------------------
-@x [27] m.469 l.9235 - e-TeX basic
- othercases print_esc("jobname")
-@y
- eTeX_revision_code: print_esc("eTeXrevision");
- othercases print_esc("jobname")
-@z
-%---------------------------------------
-@x [27] m.471 l.9260 - e-TeX basic
-job_name_code: if job_name=0 then open_log_file;
-@y
-eTeX_revision_code: do_nothing;
-job_name_code: if job_name=0 then open_log_file;
-@z
-%---------------------------------------
-@x [27] m.472 l.9276 - e-TeX basic
-job_name_code: print(job_name);
-@y
-eTeX_revision_code: print(eTeX_revision);
-job_name_code: print(job_name);
-@z
-%---------------------------------------
-@x [27] m.478 l.9386 - e-TeX protected
- if cur_cmd<=max_command then goto done2;
-@y
- if cur_cmd>=call then
- if info(link(cur_chr))=protected_token then
- begin cur_cmd:=relax; cur_chr:=no_expand_flag;
- end;
- if cur_cmd<=max_command then goto done2;
-@z
-%---------------------------------------
-@x [27] m.482 l.9434 read_toks - e-TeX read_line
-@p procedure read_toks(@!n:integer;@!r:pointer);
-@y
-@p procedure read_toks(@!n:integer;@!r:pointer;@!j:halfword);
-@z
-%---------------------------------------
-@x [27] m.483 l.9460 - e-TeX read_line
-loop@+ begin get_token;
-@y
-@<Handle \.{\\readline} and |goto done|@>;@/
-loop@+ begin get_token;
-@z
-%---------------------------------------
-@x [28] m.487 l.9512 - e-TeX cond
-@d if_char_code=0 { `\.{\\if}' }
-@y
-@d unless_code=32 {amount added for `\.{\\unless}' prefix}
-@#
-@d if_char_code=0 { `\.{\\if}' }
-@z
-%---------------------------------------
-@x [28] m.488 l.9567 - e-TeX cond
-if_test: case chr_code of
-@y
-if_test: begin if chr_code>=unless_code then print_esc("unless");
-case chr_code mod unless_code of
-@z
-%---------------------------------------
-@x [28] m.488 l.9584 - e-TeX cond
- othercases print_esc("if")
- endcases;
-@y
- @/@<Cases of |if_test| for |print_cmd_chr|@>@/
- othercases print_esc("if")
- endcases;
-end;
-@z
-%---------------------------------------
-@x [28] m.494 l.9658 pass_text - e-TeX tracing
-done: scanner_status:=save_scanner_status;
-@y
-done: scanner_status:=save_scanner_status;
-if tracing_ifs>0 then show_cur_cmd_chr;
-@z
-%---------------------------------------
-@x [28] m.496 l.9674 - e-TeX tracing_nesting
-begin p:=cond_ptr; if_line:=if_line_field(p);
-@y
-begin if if_stack[in_open]=cond_ptr then if_warning;
- {conditionals possibly not properly nested with files}
-p:=cond_ptr; if_line:=if_line_field(p);
-@z
-%---------------------------------------
-@x [28] m.498 l.9711 conditional - e-TeX cond
-begin @<Push the condition stack@>;@+save_cond_ptr:=cond_ptr;this_if:=cur_chr;@/
-@<Either process \.{\\ifcase} or set |b| to the value of a boolean condition@>;
-@y
-@!is_unless:boolean; {was this if preceded by `\.{\\unless}' ?}
-begin if tracing_ifs>0 then if tracing_commands<=1 then show_cur_cmd_chr;
-@<Push the condition stack@>;@+save_cond_ptr:=cond_ptr;
-is_unless:=(cur_chr>=unless_code); this_if:=cur_chr mod unless_code;@/
-@<Either process \.{\\ifcase} or set |b| to the value of a boolean condition@>;
-if is_unless then b:=not b;
-@z
-%---------------------------------------
-@x [28] m.501 l.9754 - e-TeX cond
-if_false_code: b:=false;
-@y
-if_false_code: b:=false;
-@/@<Cases for |conditional|@>@/
-@z
-%---------------------------------------
-@x [28] m.505 l.9793 - e-TeX sparse arrays
-begin scan_eight_bit_int; p:=box(cur_val);
-@y
-begin scan_register_num; fetch_box(p);
-@z
-%---------------------------------------
-@x [28] m.510 l.9883 - e-TeX cond
-if cur_chr>if_limit then
-@y
-begin if tracing_ifs>0 then if tracing_commands<=1 then show_cur_cmd_chr;
-if cur_chr>if_limit then
-@z
-%---------------------------------------
-@x [28] m.510 l.9894 - e-TeX cond
- end
-@y
- end;
-end
-@z
-%---------------------------------------
-@x [29] m.536 l.10348 - e-TeX basic
-print_two(sys_time div 60); print_char(":"); print_two(sys_time mod 60);
-@y
-print_two(sys_time div 60); print_char(":"); print_two(sys_time mod 60);
-if eTeX_ex then
- begin; wlog_cr; wlog('entering extended mode');
- end;
-@z
-%---------------------------------------
-@x [30] m.581 l.11282 char_warning - e-TeX tracing
-begin if tracing_lost_chars>0 then
-@y
-var old_setting: integer; {saved value of |tracing_online|}
-begin if tracing_lost_chars>0 then
- begin old_setting:=tracing_online;
- if eTeX_ex and(tracing_lost_chars>1) then tracing_online:=1;
-@z
-%---------------------------------------
-@x [30] m.581 l.11289 char_warning - e-TeX tracing
-end;
-@y
- tracing_online:=old_setting;
- end;
-end;
-@z
-%---------------------------------------
-@x [32] m.616 l.12257 - e-TeX TeXXeT
-this is essentially the depth of |push| commands in the \.{DVI} output.
-@y
-this is essentially the depth of |push| commands in the \.{DVI} output.
-
-For mixed direction text (\TeXXeT) the current text direction is called
-|cur_dir|. As the box being shipped out will never be used again and
-soon be recycled, we can simply reverse any R-text (i.e., right-to-left)
-segments of hlist nodes as well as complete hlist nodes embedded in such
-segments. Moreover this can be done iteratively rather than recursively.
-There are, however, two complications related to leaders that require
-some additional bookkeeping: (1)~One and the same hlist node might be
-used more than once (but never inside both L- and R-text); and
-(2)~leader boxes inside hlists must be aligned with respect to the left
-edge of the original hlist.
-
-A math node is changed into a kern node whenever the text direction
-remains the same, it is replaced by an |edge_node| if the text direction
-changes; the subtype of an an |hlist_node| inside R-text is changed to
-|reversed| once its hlist has been reversed.
-@!@^data structure assumptions@>
-@z
-%---------------------------------------
-@x [32] m.616 l.12259 - e-TeX TeXXeT
-@d synch_h==if cur_h<>dvi_h then
-@y
-@d reversed=1 {subtype for an |hlist_node| whose hlist has been reversed}
-@d dlist=2 {subtype for an |hlist_node| from display math mode}
-@d box_lr(#) == (qo(subtype(#))) {direction mode of a box}
-@d set_box_lr(#) == subtype(#):=set_box_lr_end
-@d set_box_lr_end(#) == qi(#)
-@#
-@d left_to_right=0
-@d right_to_left=1
-@d reflected==1-cur_dir {the opposite of |cur_dir|}
-@#
-@d synch_h==if cur_h<>dvi_h then
-@z
-%---------------------------------------
-@x [32] m.619 l.12327 hlist_out - e-TeX TeXXeT
-@!edge:scaled; {left edge of sub-box, or right edge of leader space}
-@y
-@!edge:scaled; {right edge of sub-box or leader space}
-@!prev_p:pointer; {one step behind |p|}
-@z
-%---------------------------------------
-@x [32] m.619 l.12337 hlist_out - e-TeX TeXXeT
-save_loc:=dvi_offset+dvi_ptr; base_line:=cur_v; left_edge:=cur_h;
-@y
-save_loc:=dvi_offset+dvi_ptr; base_line:=cur_v;
-prev_p:=this_box+list_offset;
-@<Initialize |hlist_out| for mixed direction typesetting@>;
-left_edge:=cur_h;
-@z
-%---------------------------------------
-@x [32] m.619 l.12340 hlist_out - e-TeX TeXXeT
-prune_movements(save_loc);
-@y
-@<Finish |hlist_out| for mixed direction typesetting@>;
-prune_movements(save_loc);
-@z
-%---------------------------------------
-@x [32] m.620 l.12359 - e-TeX TeXXeT
- p:=link(p);
-@y
- prev_p:=link(prev_p); {N.B.: not |prev_p:=p|, |p| might be |lig_trick|}
- p:=link(p);
-@z
-%---------------------------------------
-@x [32] m.622 l.12384 - e-TeX TeXXeT
-kern_node,math_node:cur_h:=cur_h+width(p);
-@y
-kern_node:cur_h:=cur_h+width(p);
-math_node: @<Handle a math node in |hlist_out|@>;
-@z
-%---------------------------------------
-@x [32] m.622 l.12386 - e-TeX TeXXeT
-othercases do_nothing
-@y
-@/@<Cases of |hlist_out| that arise in mixed direction text only@>@;
-othercases do_nothing
-@z
-%---------------------------------------
-@x [32] m.622 l.12391 - e-TeX TeXXeT
-next_p:p:=link(p);
-@y
-next_p:prev_p:=p; p:=link(p);
-@z
-%---------------------------------------
-@x [32] m.623 l.12398 - e-TeX TeXXeT
- temp_ptr:=p; edge:=cur_h;
-@y
- temp_ptr:=p; edge:=cur_h+width(p);
- if cur_dir=right_to_left then cur_h:=edge;
-@z
-%---------------------------------------
-@x [32] m.623 l.12401 - e-TeX TeXXeT
- cur_h:=edge+width(p); cur_v:=base_line;
-@y
- cur_h:=edge; cur_v:=base_line;
-@z
-%---------------------------------------
-@x [32] m.625 l.12419 - e-TeX TeXXeT
- glue_temp:=-billion
-
-@<Move right or output leaders@>=
-begin g:=glue_ptr(p); rule_wd:=width(g)-cur_g;
-@y
- glue_temp:=-billion
-@#
-@d round_glue==g:=glue_ptr(p); rule_wd:=width(g)-cur_g;
-@z
-%---------------------------------------
-@x [32] m.625 l.12438 - e-TeX TeXXeT
-rule_wd:=rule_wd+cur_g;
-@y
-rule_wd:=rule_wd+cur_g
-
-@<Move right or output leaders@>=
-begin round_glue;
-if eTeX_ex then @<Handle a glue node for mixed direction typesetting@>;
-@z
-%---------------------------------------
-@x [32] m.626 l.12454 - e-TeX TeXXeT
- edge:=cur_h+rule_wd; lx:=0;
-@y
- if cur_dir=right_to_left then cur_h:=cur_h-10;
- edge:=cur_h+rule_wd; lx:=0;
-@z
-%---------------------------------------
-@x [32] m.626 l.12460 - e-TeX TeXXeT
- cur_h:=edge-10; goto next_p;
-@y
- if cur_dir=right_to_left then cur_h:=edge
- else cur_h:=edge-10;
- goto next_p;
-@z
-%---------------------------------------
-@x [32] m.628 l.12499 - e-TeX TeXXeT
-synch_h; save_h:=dvi_h; temp_ptr:=leader_box;
-@y
-synch_h; save_h:=dvi_h; temp_ptr:=leader_box;
-if cur_dir=right_to_left then cur_h:=cur_h+leader_wd;
-@z
-%---------------------------------------
-@x [32] m.632 l.12573 - e-TeX TeXXeT
- cur_h:=left_edge+shift_amount(p); {shift the box right}
-@y
- if cur_dir=right_to_left then cur_h:=left_edge-shift_amount(p)
- else cur_h:=left_edge+shift_amount(p); {shift the box right}
-@z
-%---------------------------------------
-@x [32] m.633 l.12585 - e-TeX TeXXeT
- begin synch_h; synch_v;
- dvi_out(put_rule); dvi_four(rule_ht); dvi_four(rule_wd);
-@y
- begin if cur_dir=right_to_left then cur_h:=cur_h-rule_wd;
- synch_h; synch_v;
- dvi_out(put_rule); dvi_four(rule_ht); dvi_four(rule_wd);
- cur_h:=left_edge;
-@z
-%---------------------------------------
-@x [32] m.637 l.12651 - e-TeX TeXXeT
-begin cur_h:=left_edge+shift_amount(leader_box); synch_h; save_h:=dvi_h;@/
-@y
-begin if cur_dir=right_to_left then
- cur_h:=left_edge-shift_amount(leader_box)
- else cur_h:=left_edge+shift_amount(leader_box);
-synch_h; save_h:=dvi_h;@/
-@z
-%---------------------------------------
-@x [32] m.638 l.12688 ship_out - e-TeX TeXXeT
-@<Ship box |p| out@>;
-@y
-@<Ship box |p| out@>;
-if eTeX_ex then @<Check for LR anomalies at the end of |ship_out|@>;
-@z
-%---------------------------------------
-@x [33] m.649 l.12909 hpack - e-TeX TeXXeT
-h:=0; @<Clear dimensions to zero@>;
-@y
-h:=0; @<Clear dimensions to zero@>;
-if TeXXeT_en then @<Initialize the LR stack@>;
-@z
-%---------------------------------------
-@x [33] m.649 l.12919 hpack - e-TeX TeXXeT
-exit: hpack:=r;
-@y
-exit: if TeXXeT_en then @<Check for LR anomalies at the end of |hpack|@>;
-hpack:=r;
-@z
-%---------------------------------------
-@x [33] m.651 l.12943 - e-TeX TeXXeT
- kern_node,math_node: x:=x+width(p);
-@y
- kern_node: x:=x+width(p);
- math_node: begin x:=x+width(p);
- if TeXXeT_en then @<Adjust \(t)the LR stack for the |hpack| routine@>;
- end;
-@z
-%---------------------------------------
-@x [34] m.687 l.13514 - e-TeX middle
-\TeX's \.{\\left} and \.{\\right}. The |nucleus| of such noads is
-@y
-\TeX's \.{\\left} and \.{\\right} as well as \eTeX's \.{\\middle}.
-The |nucleus| of such noads is
-@z
-%---------------------------------------
-@x [34] m.687 l.13531 - e-TeX middle
-@d delimiter==nucleus {|delimiter| field in left and right noads}
-@y
-@d delimiter==nucleus {|delimiter| field in left and right noads}
-@d middle_noad==1 {|subtype| of right noad representing \.{\\middle}}
-@z
-%---------------------------------------
-@x [34] m.696 l.13704 - e-TeX middle
-right_noad: begin print_esc("right"); print_delimiter(delimiter(p));
- end;
-end;
-if subtype(p)<>normal then
- if subtype(p)=limits then print_esc("limits")
- else print_esc("nolimits");
-if type(p)<left_noad then print_subsidiary_data(nucleus(p),".");
-@y
-right_noad: begin if subtype(p)=normal then print_esc("right")
- else print_esc("middle");
- print_delimiter(delimiter(p));
- end;
-end;
-if type(p)<left_noad then
- begin if subtype(p)<>normal then
- if subtype(p)=limits then print_esc("limits")
- else print_esc("nolimits");
- print_subsidiary_data(nucleus(p),".");
- end;
-@z
-%---------------------------------------
-@x [36] m.727 l.14302 - e-TeX middle
-done_with_noad: r:=q; r_type:=type(r);
-@y
-done_with_noad: r:=q; r_type:=type(r);
-if r_type=right_noad then
- begin r_type:=left_noad; cur_style:=style; @<Set up the values...@>;
- end;
-@z
-%---------------------------------------
-@x [36] m.760 l.14963 - e-TeX middle
- r_type:=t;
-@y
- if type(q)=right_noad then t:=open_noad;
- r_type:=t;
-@z
-%---------------------------------------
-@x [36] m.762 l.15004 make_left_right - e-TeX middle
-begin if style<script_style then cur_size:=text_size
-else cur_size:=16*((style-text_style) div 2);
-@y
-begin cur_style:=style; @<Set up the values...@>;
-@z
-%---------------------------------------
-@x [37] m.785 l.15495 align_peek - e-TeX protected
-begin restart: align_state:=1000000; @<Get the next non-blank non-call token@>;
-@y
-begin restart: align_state:=1000000;
-repeat get_x_or_protected;
-until cur_cmd<>spacer;
-@z
-%---------------------------------------
-@x [37] m.791 l.15606 fin_col - e-TeX protected
-align_state:=1000000; @<Get the next non-blank non-call token@>;
-@y
-align_state:=1000000;
-repeat get_x_or_protected;
-until cur_cmd<>spacer;
-@z
-%---------------------------------------
-@x [37] m.807 l.15868 - e-TeX TeXXeT
- begin type(q):=hlist_node; width(q):=width(p);
-@y
- begin type(q):=hlist_node; width(q):=width(p);
- if nest[nest_ptr-1].mode_field=mmode then set_box_lr(q)(dlist); {for |ship_out|}
-@z
-%---------------------------------------
-@x [37] m.808 l.15886 - e-TeX TeXXeT
-n:=span_count(r); t:=width(s); w:=t; u:=hold_head;
-@y
-n:=span_count(r); t:=width(s); w:=t; u:=hold_head;
-set_box_lr(r)(0); {for |ship_out|}
-@z
-%---------------------------------------
-@x [38] m.814 l.16009 - e-TeX penalties
-There is one explicit parameter: |final_widow_penalty| is the amount of
-additional penalty to be inserted before the final line of the paragraph.
-@y
-There is one explicit parameter: |d| is true for partial paragraphs
-preceding display math mode; in this case the amount of additional
-penalty inserted before the final line is |display_widow_penalty|
-instead of |widow_penalty|.
-@z
-%---------------------------------------
-@x [38] m.815 l.16036 line_break - e-TeX penalties
-procedure line_break(@!final_widow_penalty:integer);
-@y
-procedure line_break(@!d:boolean);
-@z
-%---------------------------------------
-@x [38] m.815 l.16046 - e-TeX basic
-end;
-@y
-end;
-@#
-@t\4@>@<Declare \eTeX\ procedures for use by |main_control|@>
-@z
-%---------------------------------------
-@x [38] m.816 l.16066 - e-TeX last_line_fit
-link(tail):=new_param_glue(par_fill_skip_code);
-@y
-link(tail):=new_param_glue(par_fill_skip_code);
-last_line_fill:=link(tail);
-@z
-%---------------------------------------
-@x [38] m.819 l.16131 - e-TeX last_line_fit
-@d active_node_size=3 {number of words in active nodes}
-@y
-@d active_node_size_normal=3 {number of words in normal active nodes}
-@z
-%---------------------------------------
-@x [38] m.827 l.16294 - e-TeX last_line_fit
-background[6]:=shrink(q)+shrink(r);
-@y
-background[6]:=shrink(q)+shrink(r);
-@<Check for special treatment of last line of paragraph@>;
-@z
-%---------------------------------------
-@x [38] m.829 l.16345 try_break - e-TeX last_line_fit
-label exit,done,done1,continue,deactivate;
-@y
-label exit,done,done1,continue,deactivate,found,not_found;
-@z
-%---------------------------------------
-@x [38] m.845 l.16637 - e-TeX last_line_fit
-total_demerits(q):=minimal_demerits[fit_class];
-@y
-total_demerits(q):=minimal_demerits[fit_class];
-if do_last_line_fit then
- @<Store \(a)additional data in the new active node@>;
-@z
-%---------------------------------------
-@x [38] m.846 l.16650 - e-TeX last_line_fit
-print(" t="); print_int(total_demerits(q));
-@y
-print(" t="); print_int(total_demerits(q));
-if do_last_line_fit then @<Print additional data in the new active node@>;
-@z
-%---------------------------------------
-@x [38] m.851 l.16749 - e-TeX last_line_fit
-if (b>inf_bad)or(pi=eject_penalty) then
-@y
-if do_last_line_fit then @<Adjust \(t)the additional data for last line@>;
-found:
-if (b>inf_bad)or(pi=eject_penalty) then
-@z
-%---------------------------------------
-@x [38] m.852 l.16773 - e-TeX last_line_fit
- begin b:=0; fit_class:=decent_fit; {infinite stretch}
-@y
- begin if do_last_line_fit then
- begin if cur_p=null then {the last line of a paragraph}
- @<Perform computations for last line and |goto found|@>;
- shortfall:=0;
- end;
- b:=0; fit_class:=decent_fit; {infinite stretch}
-@z
-%---------------------------------------
-@x [38] m.855 l.16830 - e-TeX last_line_fit
- best_place[fit_class]:=break_node(r); best_pl_line[fit_class]:=l;
-@y
- best_place[fit_class]:=break_node(r); best_pl_line[fit_class]:=l;
- if do_last_line_fit then
- @<Store \(a)additional data for this feasible break@>;
-@z
-%---------------------------------------
-@x [39] m.863 l.17003 - e-TeX last_line_fit
- end;@+tats@/
-@y
- end;@+tats@/
-if do_last_line_fit then @<Adjust \(t)the final line of the paragraph@>;
-@z
-%---------------------------------------
-@x [39] m.864 l.17014 - e-TeX last_line_fit
-line_number(q):=prev_graf+1; total_demerits(q):=0; link(active):=q;
-@y
-line_number(q):=prev_graf+1; total_demerits(q):=0; link(active):=q;
-if do_last_line_fit then
- @<Initialize additional fields of the first active node@>;
-@z
-%---------------------------------------
-@x [39] m.866 l.17064 - e-TeX TeXXeT
-math_node: begin auto_breaking:=(subtype(cur_p)=after); kern_break;
-@y
-math_node: begin if subtype(cur_p)<L_code then auto_breaking:=odd(subtype(cur_p));
- kern_break;
-@z
-%---------------------------------------
-@x [39] m.876 l.17226 - e-TeX penalties
-post_line_break(final_widow_penalty)
-@y
-post_line_break(d)
-@z
-%---------------------------------------
-@x [39] m.877 l.17240 post_line_break - e-TeX penalties
-procedure post_line_break(@!final_widow_penalty:integer);
-@y
-procedure post_line_break(@!d:boolean);
-@z
-%---------------------------------------
-@x [39] m.877 l.17250 post_line_break - e-TeX TeXXeT
-begin @<Reverse the links of the relevant passive nodes, setting |cur_p| to the
-@y
-@!LR_ptr:pointer; {stack of LR codes}
-begin LR_ptr:=LR_save;
-@<Reverse the links of the relevant passive nodes, setting |cur_p| to the
-@z
-%---------------------------------------
-@x [39] m.877 l.17263 post_line_break - e-TeX TeXXeT
-prev_graf:=best_line-1;
-@y
-prev_graf:=best_line-1;
-LR_save:=LR_ptr;
-@z
-%---------------------------------------
-@x [39] m.879 l.17293 - e-TeX TeXXeT
- r:=q; {now |type(q)=glue_node|, |kern_node|, |math_node|, or |penalty_node|}
-@y
- r:=q; {now |type(q)=glue_node|, |kern_node|, |math_node|, or |penalty_node|}
- if type(q)=math_node then if TeXXeT_en then
- @<Adjust \(t)the LR stack for the |post_line_break| routine@>;
-@z
-%---------------------------------------
-@x [39] m.880 l.17310 - e-TeX TeXXeT
-@<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|@>;
-@y
-if TeXXeT_en then
- @<Insert LR nodes at the beginning of the current line and adjust
- the LR stack based on LR nodes in this line@>;
-@<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|@>;
-if TeXXeT_en then @<Insert LR nodes at the end of the current line@>;
-@z
-%---------------------------------------
-@x [39] m.881 l.17333 - e-TeX TeXXeT
- else if (type(q)=math_node)or(type(q)=kern_node) then width(q):=0;
-@y
- else if type(q)=kern_node then width(q):=0
- else if type(q)=math_node then
- begin width(q):=0;
- if TeXXeT_en then @<Adjust \(t)the LR stack for the |p...@>;
- end;
-@z
-%---------------------------------------
-@x [39] m.890 l.17427 - e-TeX penalties
- begin pen:=inter_line_penalty;
- if cur_line=prev_graf+1 then pen:=pen+club_penalty;
- if cur_line+2=best_line then pen:=pen+final_widow_penalty;
-@y
- begin q:=inter_line_penalties_ptr;
- if q<>null then
- begin r:=cur_line;
- if r>penalty(q) then r:=penalty(q);
- pen:=penalty(q+r);
- end
- else pen:=inter_line_penalty;
- q:=club_penalties_ptr;
- if q<>null then
- begin r:=cur_line-prev_graf;
- if r>penalty(q) then r:=penalty(q);
- pen:=pen+penalty(q+r);
- end
- else if cur_line=prev_graf+1 then pen:=pen+club_penalty;
- if d then q:=display_widow_penalties_ptr
- else q:=widow_penalties_ptr;
- if q<>null then
- begin r:=best_line-cur_line-1;
- if r>penalty(q) then r:=penalty(q);
- pen:=pen+penalty(q+r);
- end
- else if cur_line+2=best_line then
- if d then pen:=pen+display_widow_penalty
- else pen:=pen+widow_penalty;
-@z
-%---------------------------------------
-@x [40] m.891 l.17455 - e-TeX TeXXeT
-implicit kern nodes, and $p_m$ is a glue or penalty or insertion or adjust
-@y
-implicit kern or text direction nodes, and $p_m$ is a glue or penalty or
-insertion or adjust
-@z
-%---------------------------------------
-@x [40] m.891 l.17494 - e-TeX hyph_codes
-cur_lang:=init_cur_lang; l_hyf:=init_l_hyf; r_hyf:=init_r_hyf;
-@y
-cur_lang:=init_cur_lang; l_hyf:=init_l_hyf; r_hyf:=init_r_hyf;
-set_hyph_index;
-@z
-%---------------------------------------
-@x [40] m.896 l.17557 - e-TeX TeXXeT
- else if (type(s)=kern_node)and(subtype(s)=normal) then goto continue
-@y
- else if (type(s)=kern_node)and(subtype(s)=normal) then goto continue
- else if (type(s)=math_node)and(subtype(s)>=L_code) then goto continue
-@z
-%---------------------------------------
-@x [40] m.896 l.17563 - e-TeX hyph_codes
- if lc_code(c)<>0 then
- if (lc_code(c)=c)or(uc_hyph>0) then goto done2
-@y
- set_lc_code(c);
- if hc[0]<>0 then
- if (hc[0]=c)or(uc_hyph>0) then goto done2
-@z
-%---------------------------------------
-@x [40] m.897 l.17580 - e-TeX hyph_codes
- if lc_code(c)=0 then goto done3;
- if hn=63 then goto done3;
- hb:=s; incr(hn); hu[hn]:=c; hc[hn]:=lc_code(c); hyf_bchar:=non_char;
-@y
- set_lc_code(c);
- if hc[0]=0 then goto done3;
- if hn=63 then goto done3;
- hb:=s; incr(hn); hu[hn]:=c; hc[hn]:=hc[0]; hyf_bchar:=non_char;
-@z
-%---------------------------------------
-@x [40] m.898 l.17606 - e-TeX hyph_codes
- if lc_code(c)=0 then goto done3;
- if j=63 then goto done3;
- incr(j); hu[j]:=c; hc[j]:=lc_code(c);@/
-@y
- set_lc_code(c);
- if hc[0]=0 then goto done3;
- if j=63 then goto done3;
- incr(j); hu[j]:=c; hc[j]:=hc[0];@/
-@z
-%---------------------------------------
-@x [40] m.899 l.17623 - e-TeX TeXXeT
- othercases goto done1
-@y
- math_node: if subtype(s)>=L_code then goto done4@+else goto done1;
- othercases goto done1
-@z
-%---------------------------------------
-@x [42] m.934 l.18245 new_hyph_exceptions - e-TeX hyph_codes
-label reswitch, exit, found, not_found;
-@y
-label reswitch, exit, found, not_found, not_found1;
-@z
-%---------------------------------------
-@x [42] m.934 l.18255 new_hyph_exceptions - e-TeX hyph_codes
-set_cur_lang;
-@y
-set_cur_lang;
-@!init if trie_not_ready then
- begin hyph_index:=0; goto not_found1;
- end;
-tini@/
-set_hyph_index;
-not_found1:
-@z
-%---------------------------------------
-@x [42] m.937 l.18287 - e-TeX hyph_codes
-else begin if lc_code(cur_chr)=0 then
-@y
-else begin set_lc_code(cur_chr);
- if hc[0]=0 then
-@z
-%---------------------------------------
-@x [42] m.937 l.18295 - e-TeX hyph_codes
- begin incr(n); hc[n]:=lc_code(cur_chr);
-@y
- begin incr(n); hc[n]:=hc[0];
-@z
-%---------------------------------------
-@x [43] m.952 l.18583 - e-TeX hyph_codes
-trie_root:=compress_trie(trie_root); {identify equivalent subtries}
-@y
-hyph_root:=compress_trie(hyph_root);
-trie_root:=compress_trie(trie_root); {identify equivalent subtries}
-@z
-%---------------------------------------
-@x [43] m.958 l.18671 - e-TeX hyph_codes
-if trie_root=0 then {no patterns were given}
-@y
-if trie_max=0 then {no patterns were given}
-@z
-%---------------------------------------
-@x [43] m.958 l.18675 - e-TeX hyph_codes
-else begin trie_fix(trie_root); {this fixes the non-holes in |trie|}
-@y
-else begin if hyph_root>0 then trie_fix(hyph_root);
- if trie_root>0 then trie_fix(trie_root); {this fixes the non-holes in |trie|}
-@z
-%---------------------------------------
-@x [43] m.960 l.18718 new_patterns - e-TeX hyph_codes
- brace@>;
-@y
- brace@>;
- if saving_hyph_codes>0 then
- @<Store hyphenation codes for current language@>;
-@z
-%---------------------------------------
-@x [43] m.966 l.18825 init_trie - e-TeX hyph_codes
-@<Move the data into |trie|@>;
-@y
-if hyph_root<>0 then @<Pack all stored |hyph_codes|@>;
-@<Move the data into |trie|@>;
-@z
-%---------------------------------------
-@x [44] m.968 l.18841 - e-TeX saved_items
-whenever this is possible without backspacing.
-@y
-whenever this is possible without backspacing.
-
-When the second argument |s| is |false| the deleted nodes are destroyed,
-otherwise they are collected in a list starting at |split_disc|.
-@z
-%---------------------------------------
-@x [44] m.968 l.18848 prune_page_top - e-TeX saved_items
-@p function prune_page_top(@!p:pointer):pointer; {adjust top after page break}
-var prev_p:pointer; {lags one step behind |p|}
-@!q:pointer; {temporary variable for list manipulation}
-@y
-@p function prune_page_top(@!p:pointer;@!s:boolean):pointer;
- {adjust top after page break}
-var prev_p:pointer; {lags one step behind |p|}
-@!q,@!r:pointer; {temporary variables for list manipulation}
-@z
-%---------------------------------------
-@x [44] m.968 l.18859 prune_page_top - e-TeX saved_items
- link(prev_p):=p; flush_node_list(q);
-@y
- link(prev_p):=p;
- if s then
- begin if split_disc=null then split_disc:=q@+else link(r):=q;
- r:=q;
- end
- else flush_node_list(q);
-@z
-%---------------------------------------
-@x [44] m.977 l.19026 vsplit - e-TeX marks, sparse arrays
-@p function vsplit(@!n:eight_bits; @!h:scaled):pointer;
-@y
-@p @t\4@>@<Declare the function called |do_marks|@>@;
-function vsplit(@!n:halfword; @!h:scaled):pointer;
-@z
-%---------------------------------------
-@x [44] m.977 l.19032 vsplit - e-TeX sparse arrays
-begin v:=box(n);
-@y
-begin cur_val:=n; fetch_box(v);
-@z
-%---------------------------------------
-@x [44] m.977 l.19033 vsplit - e-TeX marks, saved_items
-if split_first_mark<>null then
-@y
-flush_node_list(split_disc); split_disc:=null;
-if sa_mark<>null then
- if do_marks(vsplit_init,0,sa_mark) then sa_mark:=null;
-if split_first_mark<>null then
-@z
-%---------------------------------------
-@x [44] m.977 l.19041 vsplit - e-TeX saved_items
-q:=prune_page_top(q); p:=list_ptr(v); free_node(v,box_node_size);
-@y
-q:=prune_page_top(q,saving_vdiscards>0);
-p:=list_ptr(v); free_node(v,box_node_size);
-@z
-%---------------------------------------
-@x [44] m.977 l.19042 vsplit - e-TeX sparse arrays
-if q=null then box(n):=null {the |eq_level| of the box stays the same}
-else box(n):=vpack(q,natural);
-@y
-if q<>null then q:=vpack(q,natural);
-change_box(q); {the |eq_level| of the box stays the same}
-@z
-%---------------------------------------
-@x [44] m.979 l.19067 - e-TeX marks
- if split_first_mark=null then
-@y
- if mark_class(p)<>0 then @<Update the current marks for |vsplit|@>
- else if split_first_mark=null then
-@z
-%---------------------------------------
-@x [45] m.982 l.19201 - e-TeX last_node_type
-The variables |last_penalty| and |last_kern| are similar. And
-@y
-The variables |last_penalty|, |last_kern|, and |last_node_type|
-are similar. And
-@z
-%---------------------------------------
-@x [45] m.982 l.19214 - e-TeX last_node_type
-@!last_kern:scaled; {used to implement \.{\\lastkern}}
-@y
-@!last_kern:scaled; {used to implement \.{\\lastkern}}
-@!last_node_type:integer; {used to implement \.{\\lastnodetype}}
-@z
-%---------------------------------------
-@x [45] m.991 l.19353 - e-TeX last_node_type
-last_glue:=max_halfword; last_penalty:=0; last_kern:=0;
-@y
-last_glue:=max_halfword; last_penalty:=0; last_kern:=0;
-last_node_type:=-1;
-@z
-%---------------------------------------
-@x [45] m.996 l.19420 - e-TeX last_node_type
-last_penalty:=0; last_kern:=0;
-@y
-last_penalty:=0; last_kern:=0;
-last_node_type:=type(p)+1;
-@z
-%---------------------------------------
-@x [45] m.999 l.19454 - e-TeX saved_items
-link(contrib_head):=link(p); link(p):=null; flush_node_list(p)
-@y
-link(contrib_head):=link(p); link(p):=null;
-if saving_vdiscards>0 then
- begin if page_disc=null then page_disc:=p@+else link(tail_page_disc):=p;
- tail_page_disc:=p;
- end
-else flush_node_list(p)
-@z
-%---------------------------------------
-@x [45] m.1012 l.19697 fire_up - e-TeX marks
-if bot_mark<>null then
-@y
-if sa_mark<>null then
- if do_marks(fire_up_init,0,sa_mark) then sa_mark:=null;
-if bot_mark<>null then
-@z
-%---------------------------------------
-@x [45] m.1012 l.19705 fire_up - e-TeX marks
-if (top_mark<>null)and(first_mark=null) then
-@y
-if sa_mark<>null then
- if do_marks(fire_up_done,0,sa_mark) then sa_mark:=null;
-if (top_mark<>null)and(first_mark=null) then
-@z
-%---------------------------------------
-@x [45] m.1014 l.19742 - e-TeX marks
- else if type(p)=mark_node then @<Update the values of
-@y
- else if type(p)=mark_node then
- if mark_class(p)<>0 then @<Update the current marks for |fire_up|@>
- else @<Update the values of
-@z
-%---------------------------------------
-@x [45] m.1021 l.19854 - e-TeX saved_items
- ins_ptr(p):=prune_page_top(broken_ptr(r));
-@y
- ins_ptr(p):=prune_page_top(broken_ptr(r),false);
-@z
-%---------------------------------------
-@x [45] m.1023 l.19890 - e-TeX saved_items
-ship_out(box(255)); box(255):=null;
-@y
-flush_node_list(page_disc); page_disc:=null;
-ship_out(box(255)); box(255):=null;
-@z
-%---------------------------------------
-@x [45] m.1026 l.19932 - e-TeX saved_items
-pop_nest; build_page;
-@y
-flush_node_list(page_disc); page_disc:=null;
-pop_nest; build_page;
-@z
-%---------------------------------------
-@x [47] m.1070 l.20735 normal_paragraph - e-TeX penalties
-if par_shape_ptr<>null then eq_define(par_shape_loc,shape_ref,null);
-@y
-if par_shape_ptr<>null then eq_define(par_shape_loc,shape_ref,null);
-if inter_line_penalties_ptr<>null then
- eq_define(inter_line_penalties_loc,shape_ref,null);
-@z
-%---------------------------------------
-@x [47] m.1071 l.20756 - e-TeX sparse arrays
-|box_flag+255| represent `\.{\\setbox0}' through `\.{\\setbox255}';
-codes |box_flag+256| through |box_flag+511| represent `\.{\\global\\setbox0}'
-through `\.{\\global\\setbox255}';
-code |box_flag+512| represents `\.{\\shipout}'; and codes |box_flag+513|
-through |box_flag+515| represent `\.{\\leaders}', `\.{\\cleaders}',
-@y
-|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}',
-@z
-%---------------------------------------
-@x [47] m.1071 l.20770 - e-TeX sparse arrays
-@d ship_out_flag==box_flag+512 {context code for `\.{\\shipout}'}
-@d leader_flag==box_flag+513 {context code for `\.{\\leaders}'}
-@y
-@d global_box_flag==@'10000100000 {context code for `\.{\\global\\setbox0}'}
-@d ship_out_flag==@'10000200000 {context code for `\.{\\shipout}'}
-@d leader_flag==@'10000200001 {context code for `\.{\\leaders}'}
-@z
-%---------------------------------------
-@x [47] m.1075 l.20853 box_end - e-TeX sparse arrays
-var p:pointer; {|ord_noad| for new box in math mode}
-@y
-var p:pointer; {|ord_noad| for new box in math mode}
-@!a:small_number; {global prefix}
-@z
-%---------------------------------------
-@x [47] m.1077 l.20891 - e-TeX sparse arrays
-if box_context<box_flag+256 then
- eq_define(box_base-box_flag+box_context,box_ref,cur_box)
-else geq_define(box_base-box_flag-256+box_context,box_ref,cur_box)
-@y
-begin if box_context<global_box_flag then
- begin cur_val:=box_context-box_flag; a:=0;
- end
-else begin cur_val:=box_context-global_box_flag; a:=4;
- end;
-if cur_val<256 then define(box_base+cur_val,box_ref,cur_box)
-else sa_def_box;
-end
-@z
-%---------------------------------------
-@x [47] m.1079 l.20920 begin_box - e-TeX TeXXeT
-@!m:quarterword; {the length of a replacement list}
-@y
-@!r:pointer; {running behind |p|}
-@!fm:boolean; {a final \.{\\beginM} \.{\\endM} node pair?}
-@!tx:pointer; {effective tail node}
-@!m:quarterword; {the length of a replacement list}
-@z
-%---------------------------------------
-@x [47] m.1079 l.20922 begin_box - e-TeX sparse arrays
-@!n:eight_bits; {a box number}
-begin case cur_chr of
-box_code: begin scan_eight_bit_int; cur_box:=box(cur_val);
- box(cur_val):=null; {the box becomes void, at the same level}
- end;
-copy_code: begin scan_eight_bit_int; cur_box:=copy_node_list(box(cur_val));
-@y
-@!n:halfword; {a box number}
-begin case cur_chr of
-box_code: begin scan_register_num; fetch_box(cur_box);
- change_box(null); {the box becomes void, at the same level}
- end;
-copy_code: begin scan_register_num; fetch_box(q); cur_box:=copy_node_list(q);
-@z
-%---------------------------------------
-@x [47] m.1080 l.20940 - e-TeX TeXXeT
-@<If the current list ends with a box node, delete it...@>=
-@y
-@d fetch_effective_tail_eTeX(#)== {extract |tx|,
- drop \.{\\beginM} \.{\\endM} pair}
-q:=head; p:=null;
-repeat r:=p; p:=q; fm:=false;
-if not is_char_node(q) then
- if type(q)=disc_node then
- begin for m:=1 to replace_count(q) do p:=link(p);
- if p=tx then #;
- end
- else if (type(q)=math_node)and(subtype(q)=begin_M_code) then fm:=true;
-q:=link(p);
-until q=tx; {found |r|$\to$|p|$\to$|q=tx|}
-q:=link(tx); link(p):=q; link(tx):=null;
-if q=null then if fm then confusion("tail1")
-@:this can't happen tail1}{\quad tail1@>
- else tail:=p
-else if fm then {|r|$\to$|p=begin_M|$\to$|q=end_M|}
- begin tail:=r; link(r):=null; flush_node_list(p);@+end
-@#
-@d check_effective_tail(#)==find_effective_tail_eTeX
-@d fetch_effective_tail==fetch_effective_tail_eTeX
-
-@<If the current list ends with a box node, delete it...@>=
-@z
-%---------------------------------------
-@x [47] m.1080 l.20950 - e-TeX TeXXeT
-else begin if not is_char_node(tail) then
- if (type(tail)=hlist_node)or(type(tail)=vlist_node) then
- @<Remove the last box, unless it's part of a discretionary@>;
- end;
-@y
-else begin check_effective_tail(goto done);
- if not is_char_node(tx) then
- if (type(tx)=hlist_node)or(type(tx)=vlist_node) then
- @<Remove the last box, unless it's part of a discretionary@>;
- done:end;
-@z
-%---------------------------------------
-@x [47] m.1081 l.20957 - e-TeX TeXXeT
-begin q:=head;
-repeat p:=q;
-if not is_char_node(q) then if type(q)=disc_node then
- begin for m:=1 to replace_count(q) do p:=link(p);
- if p=tail then goto done;
- end;
-q:=link(p);
-until q=tail;
-cur_box:=tail; shift_amount(cur_box):=0;
-tail:=p; link(p):=null;
-done:end
-@y
-begin fetch_effective_tail(goto done);
-cur_box:=tx; shift_amount(cur_box):=0;
-end
-@z
-%---------------------------------------
-@x [47] m.1082 l.20972 - e-TeX sparse arrays
-begin scan_eight_bit_int; n:=cur_val;
-@y
-begin scan_register_num; n:=cur_val;
-@z
-%---------------------------------------
-@x [47] m.1096 l.21156 - e-TeX penalties, TeXXeT
- else line_break(widow_penalty);
-@y
- else line_break(false);
- if LR_save<>null then
- begin flush_list(LR_save); LR_save:=null;
- end;
-@z
-%---------------------------------------
-@x [47] m.1101 l.21212 make_mark - e-TeX marks
-begin p:=scan_toks(false,true); p:=get_node(small_node_size);
-@y
-@!c:halfword; {the mark class}
-begin if cur_chr=0 then c:=0
-else begin scan_register_num; c:=cur_val;
- end;
-p:=scan_toks(false,true); p:=get_node(small_node_size);
-mark_class(p):=c;
-@z
-%---------------------------------------
-@x [47] m.1105 l.21246 delete_last - e-TeX TeXXeT
-@!m:quarterword; {the length of a replacement list}
-@y
-@!r:pointer; {running behind |p|}
-@!fm:boolean; {a final \.{\\beginM} \.{\\endM} node pair?}
-@!tx:pointer; {effective tail node}
-@!m:quarterword; {the length of a replacement list}
-@z
-%---------------------------------------
-@x [47] m.1105 l.21250 delete_last - e-TeX TeXXeT
-else begin if not is_char_node(tail) then if type(tail)=cur_chr then
- begin q:=head;
- repeat p:=q;
- if not is_char_node(q) then if type(q)=disc_node then
- begin for m:=1 to replace_count(q) do p:=link(p);
- if p=tail then return;
- end;
- q:=link(p);
- until q=tail;
- link(p):=null; flush_node_list(tail); tail:=p;
-@y
-else begin check_effective_tail(return);
- if not is_char_node(tx) then if type(tx)=cur_chr then
- begin fetch_effective_tail(return);
- flush_node_list(tx);
-@z
-%---------------------------------------
-@x [47] m.1108 l.21299 - e-TeX saved_items
-un_vbox: if chr_code=copy_code then print_esc("unvcopy")
-@y
-un_vbox: if chr_code=copy_code then print_esc("unvcopy")
- @<Cases of |un_vbox| for |print_cmd_chr|@>@/
-@z
-%---------------------------------------
-@x [47] m.1110 l.21309 unpackage - e-TeX saved_items
-label exit;
-@y
-label done, exit;
-@z
-%---------------------------------------
-@x [47] m.1110 l.21312 unpackage - e-TeX saved_items, sparse arrays
-begin c:=cur_chr; scan_eight_bit_int; p:=box(cur_val);
-@y
-begin if cur_chr>copy_code then @<Handle saved items and |goto done|@>;
-c:=cur_chr; scan_register_num; fetch_box(p);
-@z
-%---------------------------------------
-@x [47] m.1110 l.21324 unpackage - e-TeX sparse arrays
-else begin link(tail):=list_ptr(p); box(cur_val):=null;
-@y
-else begin link(tail):=list_ptr(p); change_box(null);
-@z
-%---------------------------------------
-@x [47] m.1110 l.21327 unpackage - e-TeX saved_items
-while link(tail)<>null do tail:=link(tail);
-@y
-done:
-while link(tail)<>null do tail:=link(tail);
-@z
-%---------------------------------------
-@x [47] m.1130 l.21599 - e-TeX TeXXeT
-vmode+halign,hmode+valign:init_align;
-@y
-vmode+halign:init_align;
-hmode+valign:@<Cases of |main_control| for |hmode+valign|@>@; init_align;
-@z
-%---------------------------------------
-@x [48] m.1138 l.21678 init_math - e-TeX TeXXeT
-procedure init_math;
-label reswitch,found,not_found,done;
-var w:scaled; {new or partial |pre_display_size|}
-@y
-@t\4@>@<Declare subprocedures for |init_math|@>@;
-procedure init_math;
-label reswitch,found,not_found,done;
-var w:scaled; {new or partial |pre_display_size|}
-@!j:pointer; {prototype box for display}
-@!x:integer; {new |pre_display_direction|}
-@z
-%---------------------------------------
-@x [48] m.1145 l.21736 - e-TeX TeXXeT, penalties
-begin if head=tail then {`\.{\\noindent\$\$}' or `\.{\$\${ }\$\$}'}
- begin pop_nest; w:=-max_dimen;
- end
-else begin line_break(display_widow_penalty);@/
-@y
-begin j:=null; w:=-max_dimen;
-if head=tail then {`\.{\\noindent\$\$}' or `\.{\$\${ }\$\$}'}
- @<Prepare for display after an empty paragraph@>
-else begin line_break(true);@/
-@z
-%---------------------------------------
-@x [48] m.1145 l.21749 - e-TeX TeXXeT
-eq_word_define(dimen_base+pre_display_size_code,w);
-@y
-eq_word_define(dimen_base+pre_display_size_code,w);
-LR_box:=j;
-if eTeX_ex then eq_word_define(int_base+pre_display_direction_code,x);
-@z
-%---------------------------------------
-@x [48] m.1146 l.21757 - e-TeX TeXXeT
-v:=shift_amount(just_box)+2*quad(cur_font); w:=-max_dimen;
-p:=list_ptr(just_box);
-@y
-@<Prepare for display after a non-empty paragraph@>;
-@z
-%---------------------------------------
-@x [48] m.1146 l.21772 - e-TeX TeXXeT
-done:
-@y
-done:
-@<Finish the natural width computation@>
-@z
-%---------------------------------------
-@x [48] m.1147 l.21783 - e-TeX TeXXeT
-kern_node,math_node: d:=width(p);
-@y
-kern_node: d:=width(p);
-@t\4@>@<Cases of `Let |d| be the natural width' that need special treatment@>@;
-@z
-%---------------------------------------
-@x [48] m.1185 l.22292 - e-TeX middle
- if type(q)<>left_noad then confusion("right");
-@:this can't happen right}{\quad right@>
- info(numerator(incompleat_noad)):=link(q);
- link(q):=incompleat_noad; link(incompleat_noad):=p;
-@y
- if (type(q)<>left_noad)or(delim_ptr=null) then 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;
-@z
-%---------------------------------------
-@x [48] m.1189 l.22337 - e-TeX middle
-else print_esc("right");
-@y
-@/@<Cases of |left_right| for |print_cmd_chr|@>@/
-else print_esc("right");
-@z
-%---------------------------------------
-@x [48] m.1191 l.22346 math_left_right - e-TeX middle
-begin t:=cur_chr;
-if (t=right_noad)and(cur_group<>math_left_group) then
-@y
-@!q:pointer; {resulting mlist}
-begin t:=cur_chr;
-if (t<>left_noad)and(cur_group<>math_left_group) then
-@z
-%---------------------------------------
-@x [48] m.1191 l.22351 math_left_right - e-TeX middle
- if t=left_noad then
- begin push_math(math_left_group); link(head):=p; tail:=p;
- end
- else begin p:=fin_mlist(p); unsave; {end of |math_left_group|}
-@y
- if t=middle_noad then
- begin type(p):=right_noad; subtype(p):=middle_noad;
- end;
- if t=left_noad then q:=p
- else begin q:=fin_mlist(p); unsave; {end of |math_left_group|}
- end;
- if t<>right_noad then
- begin push_math(math_left_group); link(head):=q; tail:=p;
- delim_ptr:=p;
- end
- else begin
-@z
-%---------------------------------------
-@x [48] m.1191 l.22357 math_left_right - e-TeX middle
- info(nucleus(tail)):=p;
-@y
- info(nucleus(tail)):=q;
-@z
-%---------------------------------------
-@x [48] m.1192 l.22365 - e-TeX middle
- print_err("Extra "); print_esc("right");
-@.Extra \\right.@>
- help1("I'm ignoring a \right that had no matching \left.");
-@y
- print_err("Extra ");
- if t=middle_noad then
- begin print_esc("middle");
-@.Extra \\middle.@>
- help1("I'm ignoring a \middle that had no matching \left.");
- end
- else begin print_esc("right");
-@.Extra \\right.@>
- help1("I'm ignoring a \right that had no matching \left.");
- end;
-@z
-%---------------------------------------
-@x [48] m.1194 l.22380 after_math - e-TeX TeXXeT
-procedure after_math;
-@y
-@t\4@>@<Declare subprocedures for |after_math|@>@;
-procedure after_math;
-@z
-%---------------------------------------
-@x [48] m.1194 l.22387 after_math - e-TeX TeXXeT
-begin danger:=false;
-@y
-begin danger:=false;
-@<Retrieve the prototype box@>;
-@z
-%---------------------------------------
-@x [48] m.1194 l.22394 after_math - e-TeX TeXXeT
- mlist_to_hlist; a:=hpack(link(temp_head),natural);
-@y
- mlist_to_hlist; a:=hpack(link(temp_head),natural);
- set_box_lr(a)(dlist);
-@z
-%---------------------------------------
-@x [48] m.1194 l.22397 after_math - e-TeX TeXXeT
- danger:=false;
-@y
- danger:=false;
- @<Retrieve the prototype box@>;
-@z
-%---------------------------------------
-@x [48] m.1199 l.22484 - e-TeX TeXXeT
-w:=width(b); z:=display_width; s:=display_indent;
-@y
-w:=width(b); z:=display_width; s:=display_indent;
-if pre_display_direction<0 then s:=-s-z;
-@z
-%---------------------------------------
-@x [48] m.1199 l.22499 - e-TeX TeXXeT
-resume_after_display
-@y
-@<Flush the prototype box@>;
-resume_after_display
-@z
-%---------------------------------------
-@x [48] m.1202 l.22541 - e-TeX TeXXeT
-d:=half(z-w);
-@y
-set_box_lr(b)(dlist);
-d:=half(z-w);
-@z
-%---------------------------------------
-@x [48] m.1203 l.22562 - e-TeX TeXXeT
- begin shift_amount(a):=s; append_to_vlist(a);
-@y
- begin app_display(j,a,0);
-@z
-%---------------------------------------
-@x [48] m.1204 l.22572 - e-TeX TeXXeT
-shift_amount(b):=s+d; append_to_vlist(b)
-@y
-app_display(j,b,d)
-@z
-%---------------------------------------
-@x [48] m.1205 l.22582 - e-TeX TeXXeT
- shift_amount(a):=s+z-width(a);
- append_to_vlist(a);
-@y
- app_display(j,a,z-width(a));
-@z
-%---------------------------------------
-@x [48] m.1206 l.22601 - e-TeX TeXXeT
-pop_nest;
-@y
-flush_node_list(LR_box);
-pop_nest;
-@z
-%---------------------------------------
-@x [49] m.1208 l.22626 - e-TeX protected
-control sequence can be defined to be `\.{\\long}' or `\.{\\outer}', and
-it might or might not be expanded. The prefixes `\.{\\global}', `\.{\\long}',
-@y
-control sequence can be defined to be `\.{\\long}', `\.{\\protected}',
-or `\.{\\outer}', and it might or might not be expanded. The prefixes
-`\.{\\global}', `\.{\\long}', `\.{\\protected}',
-@z
-%---------------------------------------
-@x [49] m.1209 l.22652 - e-TeX protected
- else print_esc("global");
-@y
- @/@<Cases of |prefix| for |print_cmd_chr|@>@/
- else print_esc("global");
-@z
-%---------------------------------------
-@x [49] m.1211 l.22714 prefixed_command - e-TeX tracing
- @<Discard erroneous prefixes and |return|@>;
-@y
- @<Discard erroneous prefixes and |return|@>;
- if tracing_commands>2 then if eTeX_ex then show_cur_cmd_chr;
-@z
-%---------------------------------------
-@x [49] m.1212 l.22730 - e-TeX protected
-help1("I'll pretend you didn't say \long or \outer or \global.");
-@y
-help1("I'll pretend you didn't say \long or \outer or \global.");
-if eTeX_ex then help_line[0]:=@|
- "I'll pretend you didn't say \long or \outer or \global or \protected.";
-@z
-%---------------------------------------
-@x [49] m.1213 l.22735 - e-TeX protected
-if (cur_cmd<>def)and(a mod 4<>0) then
- begin print_err("You can't use `"); print_esc("long"); print("' or `");
- print_esc("outer"); print("' with `");
-@y
-if a>=8 then
- begin j:=protected_token; a:=a-8;
- end
-else j:=0;
-if (cur_cmd<>def)and((a mod 4<>0)or(j<>0)) then
- begin 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 then
- begin help_line[0]:=@|
- "I'll pretend you didn't say \long or \outer or \protected here.";
- print("' or `"); print_esc("protected");
- end;
- print("' with `");
-@z
-%---------------------------------------
-@x [49] m.1213 l.22740 - e-TeX protected
- help1("I'll pretend you didn't say \long or \outer here.");
-@y
-@z
-%---------------------------------------
-@x [49] m.1218 l.22798 - e-TeX protected
- q:=scan_toks(true,e); define(p,call+(a mod 4),def_ref);
-@y
- q:=scan_toks(true,e);
- if j<>0 then
- begin q:=get_avail; info(q):=j; link(q):=link(def_ref);
- link(def_ref):=q;
- end;
- define(p,call+(a mod 4),def_ref);
-@z
-%---------------------------------------
-@x [49] m.1221 l.22826 - e-TeX sparse arrays
- if cur_cmd>=call then add_token_ref(cur_chr);
-@y
- if cur_cmd>=call then add_token_ref(cur_chr)
- else if (cur_cmd=register)or(cur_cmd=toks_register) then
- if (cur_chr<mem_bot)or(cur_chr>lo_mem_stat_max) then
- add_sa_ref(cur_chr);
-@z
-%---------------------------------------
-@x [49] m.1224 l.22889 - e-TeX sparse arrays
- othercases begin scan_eight_bit_int;
-@y
- othercases begin scan_register_num;
- if cur_val>255 then
- begin j:=n-count_def_code; {|int_val..box_val|}
- if j>mu_val then j:=tok_val; {|int_val..mu_val| or |tok_val|}
- find_sa_element(j,cur_val,true); add_sa_ref(cur_ptr);
- if j=tok_val then j:=toks_register@+else j:=register;
- define(p,j,cur_ptr);
- end
- else
-@z
-%---------------------------------------
-@x [49] m.1225 l.22902 - e-TeX read_line
-read_to_cs: begin scan_int; n:=cur_val;
-@y
-read_to_cs: begin j:=cur_chr; scan_int; n:=cur_val;
-@z
-%---------------------------------------
-@x [49] m.1225 l.22911 - e-TeX read_line
- p:=cur_cs; read_toks(n,p); define(p,call,cur_val);
-@y
- p:=cur_cs; read_toks(n,p,j); define(p,call,cur_val);
-@z
-%---------------------------------------
-@x [49] m.1226 l.22920 - e-TeX sparse arrays
- if cur_cmd=toks_register then
- begin scan_eight_bit_int; p:=toks_base+cur_val;
- end
- else p:=cur_chr; {|p=every_par_loc| or |output_routine_loc| or \dots}
-@y
- e:=false; {just in case, will be set |true| for sparse array elements}
- if cur_cmd=toks_register then
- if cur_chr=mem_bot then
- begin scan_register_num;
- if cur_val>255 then
- begin find_sa_element(tok_val,cur_val,true);
- cur_chr:=cur_ptr; e:=true;
- end
- else cur_chr:=toks_base+cur_val;
- end
- else e:=true;
- p:=cur_chr; {|p=every_par_loc| or |output_routine_loc| or \dots}
-@z
-%---------------------------------------
-@x [49] m.1226 l.22930 - e-TeX sparse arrays
- begin define(p,undefined_cs,null); free_avail(def_ref);
- end
- else begin if p=output_routine_loc then {enclose in curlies}
-@y
- begin sa_define(p,null)(p,undefined_cs,null); free_avail(def_ref);
- end
- else begin if (p=output_routine_loc)and not e then {enclose in curlies}
-@z
-%---------------------------------------
-@x [49] m.1226 l.22938 - e-TeX sparse arrays
- define(p,call,def_ref);
-@y
- sa_define(p,def_ref)(p,call,def_ref);
-@z
-%---------------------------------------
-@x [49] m.1227 l.22943 - e-TeX sparse arrays
-begin if cur_cmd=toks_register then
- begin scan_eight_bit_int; cur_cmd:=assign_toks; cur_chr:=toks_base+cur_val;
- end;
-if cur_cmd=assign_toks then
- begin q:=equiv(cur_chr);
- if q=null then define(p,undefined_cs,null)
- else begin add_token_ref(q); define(p,call,q);
- end;
- goto done;
- end;
-end
-@y
-if (cur_cmd=toks_register)or(cur_cmd=assign_toks) then
- begin if cur_cmd=toks_register then
- if cur_chr=mem_bot then
- begin scan_register_num;
- if cur_val<256 then q:=equiv(toks_base+cur_val)
- else begin find_sa_element(tok_val,cur_val,false);
- if cur_ptr=null then q:=null
- else q:=sa_ptr(cur_ptr);
- end;
- end
- else q:=sa_ptr(cur_chr)
- else q:=equiv(cur_chr);
- if q=null then sa_define(p,null)(p,undefined_cs,null)
- else begin add_token_ref(q); sa_define(p,q)(p,call,q);
- end;
- goto done;
- end
-@z
-%---------------------------------------
-@x [49] m.1236 l.23059 do_register_command - e-TeX sparse arrays
-begin q:=cur_cmd;
-@y
-@!e:boolean; {does |l| refer to a sparse array element?}
-@!w:integer; {integer or dimen value of |l|}
-begin q:=cur_cmd;
-e:=false; {just in case, will be set |true| for sparse array elements}
-@z
-%---------------------------------------
-@x [49] m.1236 l.23076 do_register_command - e-TeX sparse arrays
-if p<glue_val then word_define(l,cur_val)
-else begin trap_zero_glue; define(l,glue_ref,cur_val);
-@y
-if p<glue_val then sa_word_define(l,cur_val)
-else begin trap_zero_glue; sa_define(l,cur_val)(l,glue_ref,cur_val);
-@z
-%---------------------------------------
-@x [49] m.1237 l.23098 - e-TeX sparse arrays
-p:=cur_chr; scan_eight_bit_int;
-@y
-if (cur_chr<mem_bot)or(cur_chr>lo_mem_stat_max) then
- begin l:=cur_chr; p:=sa_type(l); e:=true;
- end
-else begin p:=cur_chr-mem_bot; scan_register_num;
- if cur_val>255 then
- begin find_sa_element(p,cur_val,true); l:=cur_ptr; e:=true;
- end
- else
-@z
-%---------------------------------------
-@x [49] m.1237 l.23105 - e-TeX sparse arrays
-end;
-found:
-@y
- end;
-end;
-found: if p<glue_val then@+if e then w:=sa_int(l)@+else w:=eqtb[l].int
-else if e then s:=sa_ptr(l)@+else s:=equiv(l)
-@z
-%---------------------------------------
-@x [49] m.1238 l.23111 - e-TeX sparse arrays
- if q=advance then cur_val:=cur_val+eqtb[l].int;
-@y
- if q=advance then cur_val:=cur_val+w;
-@z
-%---------------------------------------
-@x [49] m.1239 l.23118 - e-TeX sparse arrays
-begin q:=new_spec(cur_val); r:=equiv(l);
-@y
-begin q:=new_spec(cur_val); r:=s;
-@z
-%---------------------------------------
-@x [49] m.1240 l.23138 - e-TeX sparse arrays
- if p=int_val then cur_val:=mult_integers(eqtb[l].int,cur_val)
- else cur_val:=nx_plus_y(eqtb[l].int,cur_val,0)
- else cur_val:=x_over_n(eqtb[l].int,cur_val)
-else begin s:=equiv(l); r:=new_spec(s);
-@y
- if p=int_val then 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 begin r:=new_spec(s);
-@z
-%---------------------------------------
-@x [49] m.1241 l.23160 - e-TeX sparse arrays
-set_box: begin scan_eight_bit_int;
- if global then n:=256+cur_val@+else n:=cur_val;
- scan_optional_equals;
- if set_box_allowed then scan_box(box_flag+n)
-@y
-set_box: begin scan_register_num;
- if global then n:=global_box_flag+cur_val@+else n:=box_flag+cur_val;
- scan_optional_equals;
- if set_box_allowed then scan_box(n)
-@z
-%---------------------------------------
-@x [49] m.1246 l.23231 alter_integer - e-TeX interaction_mode
-var c:0..1; {0 for \.{\\deadcycles}, 1 for \.{\\insertpenalties}}
-begin c:=cur_chr; scan_optional_equals; scan_int;
-if c=0 then dead_cycles:=cur_val
-@y
-var c:small_number;
- {0 for \.{\\deadcycles}, 1 for \.{\\insertpenalties}, etc.}
-begin c:=cur_chr; scan_optional_equals; scan_int;
-if c=0 then dead_cycles:=cur_val
-@/@<Cases for |alter_integer|@>@/
-@z
-%---------------------------------------
-@x [49] m.1247 l.23240 alter_box_dimen - e-TeX sparse arrays
-@!b:eight_bits; {box number}
-begin c:=cur_chr; scan_eight_bit_int; b:=cur_val; scan_optional_equals;
-scan_normal_dimen;
-if box(b)<>null then mem[box(b)+c].sc:=cur_val;
-@y
-@!b:pointer; {box register}
-begin c:=cur_chr; scan_register_num; fetch_box(b); scan_optional_equals;
-scan_normal_dimen;
-if b<>null then mem[b+c].sc:=cur_val;
-@z
-%---------------------------------------
-@x [49] m.1248 l.23249 - e-TeX penalties
-set_shape: begin scan_optional_equals; scan_int; n:=cur_val;
- if n<=0 then p:=null
-@y
-set_shape: begin q:=cur_chr; scan_optional_equals; scan_int; n:=cur_val;
- if n<=0 then p:=null
- else if q>par_shape_loc then
- begin n:=(cur_val div 2)+1; p:=get_node(2*n+1); info(p):=n;
- n:=cur_val; mem[p+1].int:=n; {number of penalties}
- for j:=p+2 to p+n+1 do
- begin scan_int; mem[j].int:=cur_val; {penalty values}
- end;
- if not odd(n) then mem[p+n+2].int:=0; {unused}
- end
-@z
-%---------------------------------------
-@x [49] m.1248 l.23259 - e-TeX penalties
- define(par_shape_loc,shape_ref,p);
-@y
- define(q,shape_ref,p);
-@z
-%---------------------------------------
-@x [49] m.1260 l.23346 new_font - e-TeX tracing
-common_ending: equiv(u):=f; eqtb[font_id_base+f]:=eqtb[u]; font_id_text(f):=t;
-@y
-common_ending: define(u,set_font,f); eqtb[font_id_base+f]:=eqtb[u]; font_id_text(f):=t;
-@z
-%---------------------------------------
-@x [49] m.1292 l.23633 - e-TeX show_groups
- show_lists_code:print_esc("showlists");
-@y
- show_lists_code:print_esc("showlists");
- @<Cases of |xray| for |print_cmd_chr|@>@;@/
-@z
-%---------------------------------------
-@x [49] m.1293 l.23640 show_whatever - e-TeX show_ifs
-var p:pointer; {tail of a token list to show}
-@y
-var p:pointer; {tail of a token list to show}
-@!t:small_number; {type of conditional being shown}
-@!m:normal..or_code; {upper bound on |fi_or_else| codes}
-@!l:integer; {line where that conditional began}
-@!n:integer; {level of \.{\\if...\\fi} nesting}
-@z
-%---------------------------------------
-@x [49] m.1293 l.23646 show_whatever - e-TeX show_groups
-othercases @<Show the current value of some parameter or register,
-@y
-@<Cases for |show_whatever|@>@;@/
-othercases @<Show the current value of some parameter or register,
-@z
-%---------------------------------------
-@x [49] m.1295 l.23681 - e-TeX protected
-call: print("macro");
-long_call: print_esc("long macro");
-outer_call: print_esc("outer macro");
-long_outer_call: begin print_esc("long"); print_esc("outer macro");
-@y
-call,long_call,outer_call,long_outer_call: begin n:=cmd-call;
- if info(link(chr_code))=protected_token then n:=n+4;
- if odd(n div 4) then print_esc("protected");
- if odd(n) then print_esc("long");
- if odd(n div 2) then print_esc("outer");
- if n>0 then print_char(" ");
- print("macro");
-@z
-%---------------------------------------
-@x [49] m.1296 l.23689 - e-TeX sparse arrays
-begin scan_eight_bit_int; begin_diagnostic;
-print_nl("> \box"); print_int(cur_val); print_char("=");
-if box(cur_val)=null then print("void")
-else show_box(box(cur_val));
-@y
-begin scan_register_num; fetch_box(p); begin_diagnostic;
-print_nl("> \box"); print_int(cur_val); print_char("=");
-if p=null then print("void")@+else show_box(p);
-@z
-%---------------------------------------
-@x [50] m.1307 l.23831 - e-TeX basic
-dump_int(@$);@/
-@y
-dump_int(@$);@/
-@<Dump the \eTeX\ state@>@/
-@z
-%---------------------------------------
-@x [50] m.1308 l.23846 - e-TeX basic
-if x<>@$ then goto bad_fmt; {check that strings are the same}
-@y
-if x<>@$ then goto bad_fmt; {check that strings are the same}
-@/@<Undump the \eTeX\ state@>@/
-@z
-%---------------------------------------
-@x [50] m.1311 l.23900 - e-TeX sparse arrays
-dump_int(lo_mem_max); dump_int(rover);
-@y
-dump_int(lo_mem_max); dump_int(rover);
-if eTeX_ex then for k:=int_val to tok_val do dump_int(sa_root[k]);
-@z
-%---------------------------------------
-@x [50] m.1312 l.23923 - e-TeX sparse arrays
-undump(lo_mem_stat_max+1)(lo_mem_max)(rover);
-@y
-undump(lo_mem_stat_max+1)(lo_mem_max)(rover);
-if eTeX_ex then for k:=int_val to tok_val do
- undump(null)(lo_mem_max)(sa_root[k]);
-@z
-%---------------------------------------
-@x [50] m.1324 l.24117 - e-TeX hyph_codes
-dump_int(trie_max);
-@y
-dump_int(trie_max);
-dump_int(hyph_start);
-@z
-%---------------------------------------
-@x [50] m.1325 l.24145 - e-TeX hyph_codes
-undump_size(0)(trie_size)('trie size')(j); @+init trie_max:=j;@+tini
-@y
-undump_size(0)(trie_size)('trie size')(j); @+init trie_max:=j;@+tini
-undump(0)(j)(hyph_start);
-@z
-%---------------------------------------
-@x [51] m.1335 l.24365 final_cleanup - tracing
- print_int(cur_level-level_one); print_char(")");
-@y
- print_int(cur_level-level_one); print_char(")");
- if eTeX_ex then show_save_groups;
-@z
-%---------------------------------------
-@x [51] m.1335 l.24388 final_cleanup - e-TeX marks, saved_items
- if cur_mark[c]<>null then delete_token_ref(cur_mark[c]);
-@y
- if cur_mark[c]<>null then delete_token_ref(cur_mark[c]);
- if sa_mark<>null then
- if do_marks(destroy_marks,0,sa_mark) then sa_mark:=null;
- for c:=last_box_code to vsplit_code do flush_node_list(disc_ptr[c]);
-@z
-%---------------------------------------
-@x [51] m.1336 l.24398 init_prim - e-TeX basic
-begin no_new_control_sequence:=false;
-@y
-begin no_new_control_sequence:=false;
-first:=0;
-@z
-%---------------------------------------
-@x [51] m.1337 l.24413 - e-TeX basic
-if (format_ident=0)or(buffer[loc]="&") then
-@y
-@<Enable \eTeX, if requested@>@;@/
-if (format_ident=0)or(buffer[loc]="&") then
-@z
-%---------------------------------------
-@x [51] m.1337 l.24421 - e-TeX basic
- end;
-@y
- end;
-if eTeX_ex then wterm_ln('entering extended mode');
-@z
-%---------------------------------------
-@x [53] m.1362 l.24762 adv_past - e-TeX hyph_codes
- begin cur_lang:=what_lang(#); l_hyf:=what_lhm(#); r_hyf:=what_rhm(#);@+end
-@y
- begin cur_lang:=what_lang(#); l_hyf:=what_lhm(#); r_hyf:=what_rhm(#);
- set_hyph_index;
- end
-@z
-%---------------------------------------
-@x [54] m.1379 l.24956 - e-TeX additions
-@* \[54] System-dependent changes.
-@y
-@* \[53a] 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@>=
-@!init if (buffer[loc]="*")and(format_ident=" (INITEX)") then
- begin no_new_control_sequence:=false;
- @<Generate all \eTeX\ primitives@>@;
- incr(loc); eTeX_mode:=1; {enter extended mode}
- @<Initialize variables for \eTeX\ extended mode@>@;
- end;
-tini@;@/
-if not no_new_control_sequence then {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(#)==eqtb[eTeX_state_base+#].int {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|@>=
-last_node_type_code: print_esc("lastnodetype");
-eTeX_version_code: print_esc("eTeXversion");
-
-@ @<Cases for fetching an integer value@>=
-eTeX_version_code: cur_val:=eTeX_version;
-
-@ @d eTeX_ex==(eTeX_mode=1) {is this extended mode?}
-
-@<Glob...@>=
-@!eTeX_mode: 0..1; {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 to eTeX_states-1 do eTeX_state(j):=0; {disable all enhancements}
-
-@ @<Undump the \eTeX\ state@>=
-undump(0)(1)(eTeX_mode);
-if eTeX_ex then
- begin @<Initialize variables for \eTeX\ extended mode@>@;
- end
-else begin @<Initialize variables for \eTeX\ compatibility mode@>@;
- end;
-
-@ 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...@>=
-function eTeX_enabled(@!b:boolean;@!j:quarterword;@!k:halfword):boolean;
-begin if not b then
- begin print_err("Improper "); print_cmd_chr(j,k);
- help1("Sorry, this optional e-TeX feature has been disabled."); error;
- end;
-eTeX_enabled:=b;
-end;
-
-@ 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@>
-primitive("predisplaydirection",
- assign_int,int_base+pre_display_direction_code);@/
-@!@:pre_display_direction_}{\.{\\predisplaydirection} primitive@>
-primitive("lastlinefit",assign_int,int_base+last_line_fit_code);@/
-@!@:last_line_fit_}{\.{\\lastlinefit} primitive@>
-primitive("savingvdiscards",assign_int,int_base+saving_vdiscards_code);@/
-@!@:saving_vdiscards_}{\.{\\savingvdiscards} primitive@>
-primitive("savinghyphcodes",assign_int,int_base+saving_hyph_codes_code);@/
-@!@:saving_hyph_codes_}{\.{\\savinghyphcodes} primitive@>
-
-@ @d every_eof==equiv(every_eof_loc)
-
-@<Cases of |assign_toks| for |print_cmd_chr|@>=
-every_eof_loc: print_esc("everyeof");
-
-@ @<Cases for |print_param|@>=
-tracing_assigns_code:print_esc("tracingassigns");
-tracing_groups_code:print_esc("tracinggroups");
-tracing_ifs_code:print_esc("tracingifs");
-tracing_scan_tokens_code:print_esc("tracingscantokens");
-tracing_nesting_code:print_esc("tracingnesting");
-pre_display_direction_code:print_esc("predisplaydirection");
-last_line_fit_code:print_esc("lastlinefit");
-saving_vdiscards_code:print_esc("savingvdiscards");
-saving_hyph_codes_code:print_esc("savinghyphcodes");
-
-@ In order to handle \.{\\everyeof} we need an array |eof_seen| of
-boolean variables.
-
-@<Glob...@>=
-@!eof_seen : array[1..max_in_open] of boolean; {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...@>=
-procedure print_group(@!e:boolean);
-label exit;
-begin case cur_group of
- bottom_level: begin print("bottom level"); return;
- end;
- simple_group,semi_simple_group:
- begin if cur_group=semi_simple_group then print("semi ");
- print("simple");
- end;
- hbox_group,adjusted_hbox_group:
- begin if cur_group=adjusted_hbox_group then print("adjusted ");
- print("hbox");
- end;
- vbox_group: print("vbox");
- vtop_group: print("vtop");
- align_group,no_align_group:
- begin if cur_group=no_align_group then print("no ");
- print("align");
- end;
- output_group: print("output");
- disc_group: print("disc");
- insert_group: print("insert");
- vcenter_group: print("vcenter");
- math_group,math_choice_group,math_shift_group,math_left_group:
- begin print("math");
- if cur_group=math_choice_group then print(" choice")
- else if cur_group=math_shift_group then print(" shift")
- else if cur_group=math_left_group then print(" left");
- end;
- end; {there are no other cases}
-print(" group (level "); print_int(qo(cur_level)); print_char(")");
-if saved(-1)<>0 then
- begin if e then print(" entered at line ") else print(" at line ");
- print_int(saved(-1));
- end;
-exit:end;
-
-@ 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...@>=
-@!stat procedure group_trace(@!e:boolean);
-begin begin_diagnostic; print_char("{");
-if e then print("leaving ") else print("entering ");
-print_group(e); print_char("}"); end_diagnostic(false);
-end;
-tats
-
-@ 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|@>=
-current_group_level_code: print_esc("currentgrouplevel");
-current_group_type_code: print_esc("currentgrouptype");
-
-@ @<Cases for fetching an integer value@>=
-current_group_level_code: cur_val:=cur_level-level_one;
-current_group_type_code: cur_val:=cur_group;
-
-@ 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|@>=
-current_if_level_code: print_esc("currentiflevel");
-current_if_type_code: print_esc("currentiftype");
-current_if_branch_code: print_esc("currentifbranch");
-
-@ @<Cases for fetching an integer value@>=
-current_if_level_code: begin q:=cond_ptr; cur_val:=0;
- while q<>null do
- begin incr(cur_val); q:=link(q);
- end;
- end;
-current_if_type_code: if cond_ptr=null then cur_val:=0
- else if cur_if<unless_code then cur_val:=cur_if+1
- else cur_val:=-(cur_if-unless_code+1);
-current_if_branch_code:
- if (if_limit=or_code)or(if_limit=else_code) then cur_val:=1
- else if if_limit=fi_code then cur_val:=-1
- else cur_val:=0;
-
-@ 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|@>=
-font_char_wd_code: print_esc("fontcharwd");
-font_char_ht_code: print_esc("fontcharht");
-font_char_dp_code: print_esc("fontchardp");
-font_char_ic_code: print_esc("fontcharic");
-
-@ @<Cases for fetching a dimension value@>=
-font_char_wd_code,
-font_char_ht_code,
-font_char_dp_code,
-font_char_ic_code: begin scan_font_ident; q:=cur_val; scan_char_num;
- if (font_bc[q]<=cur_val)and(font_ec[q]>=cur_val) then
- begin i:=char_info(q)(qi(cur_val));
- case m of
- font_char_wd_code: cur_val:=char_width(q)(i);
- font_char_ht_code: cur_val:=char_height(q)(height_depth(i));
- font_char_dp_code: cur_val:=char_depth(q)(height_depth(i));
- font_char_ic_code: cur_val:=char_italic(q)(i);
- end; {there are no other cases}
- end
- else cur_val:=0;
- end;
-
-@ 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|@>=
-par_shape_length_code: print_esc("parshapelength");
-par_shape_indent_code: print_esc("parshapeindent");
-par_shape_dimen_code: print_esc("parshapedimen");
-
-@ @<Cases for fetching a dimension value@>=
-par_shape_length_code,
-par_shape_indent_code,
-par_shape_dimen_code: begin q:=cur_chr-par_shape_length_code; scan_int;
- if (par_shape_ptr=null)or(cur_val<=0) then cur_val:=0
- else begin if q=2 then
- begin q:=cur_val mod 2; cur_val:=(cur_val+q)div 2;
- end;
- if cur_val>info(par_shape_ptr) then cur_val:=info(par_shape_ptr);
- cur_val:=mem[par_shape_ptr+2*cur_val-q].sc;
- end;
- cur_val_level:=dimen_val;
- end;
-
-@ 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|@>=
-show_groups:print_esc("showgroups");
-
-@ @<Cases for |show_whatever|@>=
-show_groups: begin begin_diagnostic; show_save_groups;
- end;
-
-@ @<Types...@>=
-@!save_pointer=0..save_size; {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...@>=
-procedure show_save_groups;
-label found1,found2,found,done;
-var p:0..nest_size; {index into |nest|}
-@!m:-mmode..mmode; {mode}
-@!v:save_pointer; {saved value of |save_ptr|}
-@!l:quarterword; {saved value of |cur_level|}
-@!c:group_code; {saved value of |cur_group|}
-@!a:-1..1; {to keep track of alignments}
-@!i:integer;
-@!j:quarterword;
-@!s:str_number;
-begin 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@+begin print_nl("### "); print_group(true);
- if cur_group=bottom_level then goto done;
- repeat m:=nest[p].mode_field;
- if p>0 then decr(p) else m:=vmode;
- until m<>hmode;
- print(" (");
- case cur_group of
- simple_group: begin incr(p); goto found2;
- end;
- hbox_group,adjusted_hbox_group: s:="hbox";
- vbox_group: s:="vbox";
- vtop_group: s:="vtop";
- align_group: if a=0 then
- begin if m=-vmode then s:="halign" else s:="valign";
- a:=1; goto found1;
- end
- else begin if a=1 then print("align entry") else print_esc("cr");
- if p>=a then p:=p-a;
- a:=0; goto found;
- end;
- no_align_group:
- begin incr(p); a:=-1; print_esc("noalign"); goto found2;
- end;
- output_group:
- begin print_esc("output"); goto found;
- end;
- math_group: goto found2;
- disc_group,math_choice_group:
- begin if cur_group=disc_group then print_esc("discretionary")
- else print_esc("mathchoice");
- for i:=1 to 3 do if i<=saved(-2) then print("{}");
- goto found2;
- end;
- insert_group:
- begin if saved(-2)=255 then print_esc("vadjust")
- else begin print_esc("insert"); print_int(saved(-2));
- end;
- goto found2;
- end;
- vcenter_group: begin s:="vcenter"; goto found1;
- end;
- semi_simple_group: begin incr(p); print_esc("begingroup"); goto found;
- end;
- math_shift_group:
- begin if m=mmode then print_char("$")
- else if nest[p].mode_field=mmode then
- begin print_cmd_chr(eq_no,saved(-2)); goto found;
- end;
- print_char("$"); goto found;
- end;
- math_left_group:
- begin if type(nest[p+1].eTeX_aux_field)=left_noad then print_esc("left")
- else print_esc("middle");
- goto found;
- end;
- end; {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)
- end;
-done: save_ptr:=v; cur_level:=l; cur_group:=c;
-end;
-
-@ @<Show the box packaging info@>=
-if saved(-2)<>0 then
- begin print_char(" ");
- if saved(-3)=exactly then print("to") else print("spread");
- print_scaled(saved(-2)); print("pt");
- end
-
-@ @<Show the box context@>=
-i:=saved(-4);
-if i<>0 then
- if i<box_flag then
- begin if abs(nest[p].mode_field)=vmode then j:=hmove else j:=vmove;
- if i>0 then print_cmd_chr(j,0) else print_cmd_chr(j,1);
- print_scaled(abs(i)); print("pt");
- end
- else if i<ship_out_flag then
- begin if i>=global_box_flag then
- begin print_esc("global"); i:=i-(global_box_flag-box_flag);
- end;
- print_esc("setbox"); print_int(i-box_flag); print_char("=");
- end
- 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...@>=
-procedure@?scan_general_text; forward;@t\2@>
-
-@ 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...@>=
-procedure scan_general_text;
-label found;
-var s:normal..absorbing; {to save |scanner_status|}
-@!w:pointer; {to save |warning_index|}
-@!d:pointer; {to save |def_ref|}
-@!p:pointer; {tail of the token list being built}
-@!q:pointer; {new node being added to the token list via |store_new_token|}
-@!unbalance:halfword; {number of unmatched left braces}
-begin 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@+ begin get_token;
- if cur_tok<right_brace_limit then
- if cur_cmd<right_brace then incr(unbalance)
- else begin decr(unbalance);
- if unbalance=0 then goto found;
- end;
- store_new_token(cur_tok);
- end;
-found: q:=link(def_ref); free_avail(def_ref); {discard reference count}
-if q=null then cur_val:=temp_head @+ else cur_val:=p;
-link(temp_head):=q;
-scanner_status:=s; warning_index:=w; def_ref:=d;
-end;
-
-@ 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|@>=
-show_tokens:print_esc("showtokens");
-
-@ 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 then print_esc("unexpanded")
-else print_esc("detokenize")
-
-@ @<Handle \.{\\unexpanded} or \.{\\detokenize} and |return|@>=
-if odd(cur_chr) then
- begin c:=cur_chr; scan_general_text;
- if c=1 then the_toks:=cur_val
- else begin 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; the_toks:=str_toks(b);
- end;
- return;
- end
-
-@ 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|@>=
-show_ifs:print_esc("showifs");
-
-@
-@d print_if_line(#)==if #<>0 then
- begin print(" entered on line "); print_int(#);
- end
-
-@<Cases for |show_whatever|@>=
-show_ifs: begin begin_diagnostic; print_nl(""); print_ln;
- if cond_ptr=null then
- begin print_nl("### "); print("no active conditionals");
- end
- else begin p:=cond_ptr; n:=0;
- repeat incr(n); p:=link(p);@+until p=null;
- p:=cond_ptr; t:=cur_if; l:=if_line; m:=if_limit;
- repeat print_nl("### level "); print_int(n); print(": ");
- print_cmd_chr(if_test,t);
- if m=fi_code then print_esc("else");
- print_if_line(l);
- decr(n); t:=subtype(p); l:=if_line_field(p); m:=type(p); p:=link(p);
- until p=null;
- end;
- end;
-
-@ 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 then print_esc("interactionmode")
-
-@ @<Cases for `Fetch the |dead_cycles| or the |insert_penalties|'@>=
-else if m=2 then cur_val:=interaction
-
-@ @<Declare \eTeX\ procedures for use...@>=
-procedure@?new_interaction; forward;@t\2@>
-
-@ @<Cases for |alter_integer|@>=
-else if c=2 then
- begin if (cur_val<batch_mode)or(cur_val>error_stop_mode) then
- begin 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);
- end
- else begin cur_chr:=cur_val; new_interaction;
- end;
- end
-
-@ 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 then print_esc("middle")
-
-@ In constructions such as
-$$\vbox{\halign{\.{#}\hfil\cr
-{}\\hbox to \\hsize\{\cr
-\hskip 25pt \\hskip 0pt plus 0.0001fil\cr
-\hskip 25pt ...\cr
-\hskip 25pt \\hfil\\penalty-200\\hfilneg\cr
-\hskip 25pt ...\}\cr}}$$
-the stretch components of \.{\\hfil} and \.{\\hfilneg} compensate; they may,
-however, get modified in order to prevent arithmetic overflow during
-|hlist_out| when each of them is multiplied by a large |glue_set| value.
-
-Since this ``glue rounding'' depends on state variables |cur_g| and
-|cur_glue| and \TeXXeT\ is supposed to emulate the behaviour of \TeXeT\
-(plus a suitable postprocessor) as close as possible the glue rounding
-cannot be postponed until (segments of) an hlist has been reversed.
-
-The code below is invoked after the effective width, |rule_wd|, of a glue
-node has been computed. The glue node is either converted into a kern node
-or, for leaders, the glue specification is replaced by an equivalent rigid
-one; the subtype of the glue node remains unchanged.
-
-@<Handle a glue node for mixed...@>=
-if (((g_sign=stretching) and (stretch_order(g)=g_order)) or
- ((g_sign=shrinking) and (shrink_order(g)=g_order))) then
- begin fast_delete_glue_ref(g);
- if subtype(p)<a_leaders then
- begin type(p):=kern_node; width(p):=rule_wd;
- end
- else begin g:=get_node(glue_spec_size);@/
- stretch_order(g):=filll+1; shrink_order(g):=filll+1; {will never match}
- width(g):=rule_wd; stretch(g):=0; shrink(g):=0; glue_ptr(p):=g;
- end;
- end
-
-@ The optional |TeXXeT| feature of \eTeX\ contains the code for mixed
-left-to-right and right-to-left typesetting. This code is inspired by
-but different from \TeXeT\ as presented by Donald~E. Knuth and Pierre
-MacKay in {\sl TUGboat\/} {\bf 8}, 14--25, 1987.
-@^Knuth, Donald Ervin@>
-@^MacKay, Pierre@>
-
-In order to avoid confusion with \TeXeT\ the present implementation of
-mixed direction typesetting is called \TeXXeT. It differs from \TeXeT\
-in several important aspects: (1)~Right-to-left text is reversed
-explicitly by the |ship_out| routine and is written to a normal \.{DVI}
-file without any |begin_reflect| or |end_reflect| commands; (2)~a
-|math_node| is (ab)used instead of a |whatsit_node| to record the
-\.{\\beginL}, \.{\\endL}, \.{\\beginR}, and \.{\\endR} text direction
-primitives in order to keep the influence on the line breaking algorithm
-for pure left-to-right text as small as possible; (3)~right-to-left text
-interrupted by a displayed equation is automatically resumed after that
-equation; and (4)~the |valign| command code with a non-zero command
-modifier is (ab)used for the text direction primitives.
-
-Nevertheless there is a subtle difference between \TeX\ and \TeXXeT\
-that may influence the line breaking algorithm for pure left-to-right
-text. When a paragraph containing math mode material is broken into
-lines \TeX\ may generate lines where math mode material is not enclosed
-by properly nested \.{\\mathon} and \.{\\mathoff} nodes. Unboxing such
-lines as part of a new paragraph may have the effect that hyphenation is
-attempted for `words' originating from math mode or that hyphenation is
-inhibited for words originating from horizontal mode.
-
-In \TeXXeT\ additional \.{\\beginM}, resp.\ \.{\\endM} math nodes are
-supplied at the start, resp.\ end of lines such that math mode material
-inside a horizontal list always starts with either \.{\\mathon} or
-\.{\\beginM} and ends with \.{\\mathoff} or \.{\\endM}. These
-additional nodes are transparent to operations such as \.{\\unskip},
-\.{\\lastpenalty}, or \.{\\lastbox} but they do have the effect that
-hyphenation is never attempted for `words' originating from math mode
-and is never inhibited for words originating from horizontal mode.
-
-@d TeXXeT_state==eTeX_state(TeXXeT_code)
-@d TeXXeT_en==(TeXXeT_state>0) {is \TeXXeT\ enabled?}
-
-@<Cases for |print_param|@>=
-eTeX_state_code+TeXXeT_code:print_esc("TeXXeTstate");
-
-@ @<Generate all \eTeX...@>=
-primitive("TeXXeTstate",assign_int,eTeX_state_base+TeXXeT_code);
-@!@:TeXXeT_state_}{\.{\\TeXXeT_state} primitive@>
-primitive("beginL",valign,begin_L_code);
-@!@:beginL_}{\.{\\beginL} primitive@>
-primitive("endL",valign,end_L_code);
-@!@:endL_}{\.{\\endL} primitive@>
-primitive("beginR",valign,begin_R_code);
-@!@:beginR_}{\.{\\beginR} primitive@>
-primitive("endR",valign,end_R_code);
-@!@:endR_}{\.{\\endR} primitive@>
-
-@ @<Cases of |valign| for |print_cmd_chr|@>=
-else case chr_code of
- begin_L_code: print_esc("beginL");
- end_L_code: print_esc("endL");
- begin_R_code: print_esc("beginR");
- othercases print_esc("endR")
- endcases
-
-@ @<Cases of |main_control| for |hmode+valign|@>=
-if cur_chr>0 then
- begin if eTeX_enabled(TeXXeT_en,cur_cmd,cur_chr) then
-@.Improper \\beginL@>
-@.Improper \\endL@>
-@.Improper \\beginR@>
-@.Improper \\endR@>
- tail_append(new_math(0,cur_chr));
- end
-else
-
-@ An hbox with subtype dlist will never be reversed, even when embedded
-in right-to-left text.
-
-@<Display if this box is never to be reversed@>=
-if (type(p)=hlist_node)and(box_lr(p)=dlist) then print(", display")
-
-@ A number of routines are based on a stack of one-word nodes whose
-|info| fields contain |end_M_code|, |end_L_code|, or |end_R_code|. The
-top of the stack is pointed to by |LR_ptr|.
-
-When the stack manipulation macros of this section are used below,
-variable |LR_ptr| might be the global variable declared here for |hpack|
-and |ship_out|, or might be local to |post_line_break|.
-
-@d put_LR(#)==begin temp_ptr:=get_avail; info(temp_ptr):=#;
- link(temp_ptr):=LR_ptr; LR_ptr:=temp_ptr;
- end
-@#
-@d push_LR(#)==put_LR(end_LR_type(#))
-@#
-@d pop_LR==begin temp_ptr:=LR_ptr; LR_ptr:=link(temp_ptr);
- free_avail(temp_ptr);
- end
-
-@<Glob...@>=
-@!LR_ptr:pointer; {stack of LR codes for |hpack|, |ship_out|, and |init_math|}
-@!LR_problems:integer; {counts missing begins and ends}
-@!cur_dir:small_number; {current text direction}
-
-@ @<Set init...@>=
-LR_ptr:=null; LR_problems:=0; cur_dir:=left_to_right;
-
-@ @<Insert LR nodes at the beg...@>=
-begin q:=link(temp_head);
-if LR_ptr<>null then
- begin temp_ptr:=LR_ptr; r:=q;
- repeat s:=new_math(0,begin_LR_type(info(temp_ptr))); link(s):=r; r:=s;
- temp_ptr:=link(temp_ptr);
- until temp_ptr=null;
- link(temp_head):=r;
- end;
-while q<>cur_break(cur_p) do
- begin if not is_char_node(q) then
- if type(q)=math_node then @<Adjust \(t)the LR stack for the |p...@>;
- q:=link(q);
- end;
-end
-
-@ @<Adjust \(t)the LR stack for the |p...@>=
-if end_LR(q) then
- begin if LR_ptr<>null then if info(LR_ptr)=end_LR_type(q) then pop_LR;
- end
-else push_LR(q)
-
-@ We use the fact that |q| now points to the node with \.{\\rightskip} glue.
-
-@<Insert LR nodes at the end...@>=
-if LR_ptr<>null then
- begin s:=temp_head; r:=link(s);
- while r<>q do
- begin s:=r; r:=link(s);
- end;
- r:=LR_ptr;
- while r<>null do
- begin temp_ptr:=new_math(0,info(r));
- link(s):=temp_ptr; s:=temp_ptr; r:=link(r);
- end;
- link(s):=q;
- end
-
-@ @<Initialize the LR stack@>=
-put_LR(before) {this will never match}
-
-@ @<Adjust \(t)the LR stack for the |hp...@>=
-if end_LR(p) then
- if info(LR_ptr)=end_LR_type(p) then pop_LR
- else begin incr(LR_problems); type(p):=kern_node; subtype(p):=explicit;
- end
-else push_LR(p)
-
-@ @<Check for LR anomalies at the end of |hp...@>=
-begin if info(LR_ptr)<>before then
- begin while link(q)<>null do q:=link(q);
- repeat temp_ptr:=q; q:=new_math(0,info(LR_ptr)); link(temp_ptr):=q;
- LR_problems:=LR_problems+10000; pop_LR;
- until info(LR_ptr)=before;
- end;
-if LR_problems>0 then
- begin @<Report LR problems@>; goto common_ending;
- end;
-pop_LR;
-if LR_ptr<>null then confusion("LR1");
-@:this can't happen LR1}{\quad LR1@>
-end
-
-@ @<Report LR problems@>=
-begin print_ln; print_nl("\endL or \endR problem (");@/
-print_int(LR_problems div 10000); print(" missing, ");@/
-print_int(LR_problems mod 10000); print(" extra");@/
-LR_problems:=0;
-end
-
-@ @<Initialize |hlist_out| for mixed...@>=
-if eTeX_ex then
- begin @<Initialize the LR stack@>;
- if box_lr(this_box)=dlist then
- if cur_dir=right_to_left then
- begin cur_dir:=left_to_right; cur_h:=cur_h-width(this_box);
- end
- else set_box_lr(this_box)(0);
- if (cur_dir=right_to_left)and(box_lr(this_box)<>reversed) then
- @<Reverse the complete hlist and set the subtype to |reversed|@>;
- end
-
-@ @<Finish |hlist_out| for mixed...@>=
-if eTeX_ex then
- begin @<Check for LR anomalies at the end of |hlist_out|@>;
- if box_lr(this_box)=dlist then cur_dir:=right_to_left;
- end
-
-@ @<Handle a math node in |hlist_out|@>=
-begin if eTeX_ex then
- @<Adjust \(t)the LR stack for the |hlist_out| routine; if necessary
- reverse an hlist segment and |goto reswitch|@>;
- cur_h:=cur_h+width(p);
- end
-
-@ Breaking a paragraph into lines while \TeXXeT\ is disabled may result
-in lines whith unpaired math nodes. Such hlists are silently accepted
-in the absence of text direction directives.
-
-@d LR_dir(#)==(subtype(#) div R_code) {text direction of a `math node'}
-
-@<Adjust \(t)the LR stack for the |hl...@>=
-begin if end_LR(p) then
- if info(LR_ptr)=end_LR_type(p) then pop_LR
- else begin if subtype(p)>L_code then incr(LR_problems);
- end
-else begin push_LR(p);
- if LR_dir(p)<>cur_dir then
- @<Reverse an hlist segment and |goto reswitch|@>;
- end;
-type(p):=kern_node;
-end
-
-@ @<Check for LR anomalies at the end of |hl...@>=
-begin while info(LR_ptr)<>before do
- begin if info(LR_ptr)>L_code then LR_problems:=LR_problems+10000;
- pop_LR;
- end;
-pop_LR;
-end
-
-@ @d edge_node=style_node {a |style_node| does not occur in hlists}
-@d edge_node_size=style_node_size {number of words in an edge node}
-@d edge_dist(#)==depth(#) {new |left_edge| position relative to |cur_h|
- (after |width| has been taken into account)}
-
-@<Declare procedures needed in |hlist_out|, |vlist_out|@>=
-function new_edge(@!s:small_number;@!w:scaled):pointer;
- {create an edge node}
-var p:pointer; {the new node}
-begin p:=get_node(edge_node_size); type(p):=edge_node; subtype(p):=s;
-width(p):=w; edge_dist(p):=0; {the |edge_dist| field will be set later}
-new_edge:=p;
-end;
-
-@ @<Cases of |hlist_out| that arise...@>=
-edge_node: begin cur_h:=cur_h+width(p);
- left_edge:=cur_h+edge_dist(p); cur_dir:=subtype(p);
- end;
-
-@ We detach the hlist, start a new one consisting of just one kern node,
-append the reversed list, and set the width of the kern node.
-
-@<Reverse the complete hlist...@>=
-begin save_h:=cur_h; temp_ptr:=p; p:=new_kern(0); link(prev_p):=p;
-cur_h:=0; link(p):=reverse(this_box,null,cur_g,cur_glue); width(p):=-cur_h;
-cur_h:=save_h; set_box_lr(this_box)(reversed);
-end
-
-@ We detach the remainder of the hlist, replace the math node by
-an edge node, and append the reversed hlist segment to it; the tail of
-the reversed segment is another edge node and the remainder of the
-original list is attached to it.
-
-@<Reverse an hlist segment...@>=
-begin save_h:=cur_h; temp_ptr:=link(p); rule_wd:=width(p);
-free_node(p,small_node_size);
-cur_dir:=reflected; p:=new_edge(cur_dir,rule_wd); link(prev_p):=p;
-cur_h:=cur_h-left_edge+rule_wd;
-link(p):=reverse(this_box,new_edge(reflected,0),cur_g,cur_glue);
-edge_dist(p):=cur_h; cur_dir:=reflected; cur_h:=save_h;
-goto reswitch;
-end
-
-@ OLD VERSION.
-The |reverse| function defined here is responsible to reverse the
-nodes of an hlist (segment). The first parameter |this_box| is the enclosing
-hlist node, the second parameter |t| is to become the tail of the reversed
-list, and the global variable |temp_ptr| is the head of the list to be
-reversed. Finally |cur_g| and |cur_glue| are the current glue rounding state
-variables, to be updated by this function. We remove nodes from the original
-list and add them to the head of the new one.
-
-@<Declare procedures needed in |hlist_out|, |vlist_out|@>=
-function reverse(@!this_box,@!t:pointer; var cur_g:scaled;
- var cur_glue:real):pointer;
-label reswitch,next_p,done;
-var l:pointer; {the new list}
-@!p:pointer; {the current node}
-@!q:pointer; {the next node}
-@!g_order: glue_ord; {applicable order of infinity for glue}
-@!g_sign: normal..shrinking; {selects type of glue}
-@!glue_temp:real; {glue value before rounding}
-@!m,@!n:halfword; {count of unmatched math nodes}
-begin g_order:=glue_order(this_box); g_sign:=glue_sign(this_box);
-l:=t; p:=temp_ptr; m:=min_halfword; n:=min_halfword;
-loop@+ begin while p<>null do
- @<Move node |p| to the new list and go to the next node;
- or |goto done| if the end of the reflected segment has been reached@>;
- if (t=null)and(m=min_halfword)and(n=min_halfword) then goto done;
- p:=new_math(0,info(LR_ptr)); LR_problems:=LR_problems+10000;
- {manufacture one missing math node}
- end;
-done:reverse:=l;
-end;
-
-@ NEW VERSION.
-The |reverse| function defined here is responsible to reverse (parts of)
-the nodes of an hlist. The first parameter |this_box| is the enclosing
-hlist node, the second parameter |t| is to become the tail of the reversed
-list, and the global variable |temp_ptr| is the head of the list to be
-reversed. Finally |cur_g| and |cur_glue| are the current glue rounding
-state variables, to be updated by this function.
-
-@<Declare procedures needed in |hlist_out|, |vlist_out|@>=
-@{
-@t\4@>@<Declare subprocedures for |reverse|@>@;
-function reverse(@!this_box,@!t:pointer; var cur_g:scaled;
- var cur_glue:real):pointer;
-label reswitch,next_p,done;
-var l:pointer; {the new list}
-@!p:pointer; {the current node}
-@!q:pointer; {the next node}
-@!g_order: glue_ord; {applicable order of infinity for glue}
-@!g_sign: normal..shrinking; {selects type of glue}
-@!glue_temp:real; {glue value before rounding}
-@!m,@!n:halfword; {count of unmatched math nodes}
-begin g_order:=glue_order(this_box); g_sign:=glue_sign(this_box);
-@<Build a list of segments and determine their widths@>;
-l:=t; p:=temp_ptr; m:=min_halfword; n:=min_halfword;
-loop@+ begin while p<>null do
- @<Move node |p| to the new list and go to the next node;
- or |goto done| if the end of the reflected segment has been reached@>;
- if (t=null)and(m=min_halfword)and(n=min_halfword) then goto done;
- p:=new_math(0,info(LR_ptr)); LR_problems:=LR_problems+10000;
- {manufacture one missing math node}
- end;
-done:reverse:=l;
-end;
-@}
-
-@ We cannot simply remove nodes from the original list and add them to the
-head of the new one; this might reverse the order of whatsit nodes such
-that, e.g., a |write_node| for a stream appears before the |open_node|
-and\slash or after the |close_node| for that stream.
-
-All whatsit nodes as well as hlist and vlist nodes containing such nodes
-must not be permuted. A sequence of hlist and vlist nodes not containing
-whatsit nodes as well as char, ligature, rule, kern, and glue nodes together
-with math nodes not changing the text direction can be explicitly reversed.
-Embedded sections of left-to-right text are treated as a unit and all
-remaining nodes are irrelevant and can be ignored.
-
-In a first step we determine the width of various segments of the hlist to
-be reversed: (1)~embedded left-to-right text, (2)~sequences of permutable or
-irrelevant nodes, (3)~sequences of whatsit or irrelevant nodes, and
-(4)~individual hlist and vlist nodes containing whatsit nodes.
-
-@d segment_node=style_node
-@d segment_node_size=style_node_size {number of words in a segment node}
-@d segment_first(#)==info(#+2) {first node of the segment}
-@d segment_last(#)==link(#+2) {last node of the segment}
-
-@<Declare subprocedures for |reverse|@>=
-function new_segment(@!s:small_number;@!f:pointer):pointer;
- {create a segment node}
-var p:pointer; {the new node}
-begin p:=get_node(segment_node_size); type(p):=segment_node; subtype(p):=s;
-width(p):=0; {the |width| field will be set later}
-segment_first(p):=f; segment_last(p):=f;
-new_segment:=p;
-end;
-
-@ @<Build a list of segments and determine their widths@>=
-begin
-end
-
-@ Here is a recursive subroutine that determines if the hlist or vlist
-node~|p| contains whatsit nodes.
-
-@<Declare subprocedures for |reverse|@>=
-function has_whatsit(@!p:pointer):boolean;
-label exit;
-begin p:=list_ptr(p); has_whatsit:=true;
-while p<>null do
- begin if not is_char_node(p) then
- case type(p) of
- hlist_node, vlist_node: if has_whatsit(p) then goto exit;
- whatsit_node: goto exit;
- othercases do_nothing
- endcases;@/
- p:=link(p);
- end;
-has_whatsit:=false;
-exit: end;
-
-@ @<Move node |p| to the new list...@>=
-reswitch: if is_char_node(p) then
- repeat f:=font(p); c:=character(p);
- cur_h:=cur_h+char_width(f)(char_info(f)(c));
- q:=link(p); link(p):=l; l:=p; p:=q;
- until not is_char_node(p)
-else @<Move the non-|char_node| |p| to the new list@>
-
-@ @<Move the non-|char_node| |p| to the new list@>=
-begin q:=link(p);
-case type(p) of
-hlist_node,vlist_node,rule_node,kern_node: rule_wd:=width(p);
-@t\4@>@<Cases of |reverse| that need special treatment@>@;
-edge_node: confusion("LR2");
-@:this can't happen LR2}{\quad LR2@>
-othercases goto next_p
-endcases;@/
-cur_h:=cur_h+rule_wd;
-next_p: link(p):=l;
-if type(p)=kern_node then if (rule_wd=0)or(l=null) then
- begin free_node(p,small_node_size); p:=l;
- end;
-l:=p; p:=q;
-end
-
-@ Here we compute the effective width of a glue node as in |hlist_out|.
-
-@<Cases of |reverse|...@>=
-glue_node: begin round_glue;
- @<Handle a glue node for mixed...@>;
- end;
-
-@ A ligature node is replaced by a char node.
-
-@<Cases of |reverse|...@>=
-ligature_node: begin flush_node_list(lig_ptr(p));
- temp_ptr:=p; p:=get_avail; mem[p]:=mem[lig_char(temp_ptr)]; link(p):=q;
- free_node(temp_ptr,small_node_size); goto reswitch;
- end;
-
-@ Math nodes in an inner reflected segment are modified, those at the
-outer level are changed into kern nodes.
-
-@<Cases of |reverse|...@>=
-math_node: begin rule_wd:=width(p);
-if end_LR(p) then
- if info(LR_ptr)<>end_LR_type(p) then
- begin type(p):=kern_node; incr(LR_problems);
- end
- else begin pop_LR;
- if n>min_halfword then
- begin decr(n); decr(subtype(p)); {change |after| into |before|}
- end
- else begin type(p):=kern_node;
- if m>min_halfword then decr(m)
- else @<Finish the reversed hlist segment and |goto done|@>;
- end;
- end
-else begin push_LR(p);
- if (n>min_halfword)or(LR_dir(p)<>cur_dir) then
- begin incr(n); incr(subtype(p)); {change |before| into |after|}
- end
- else begin type(p):=kern_node; incr(m);
- end;
- end;
-end;
-
-@ Finally we have found the end of the hlist segment to be reversed; the
-final math node is released and the remaining list attached to the
-edge node terminating the reversed segment.
-
-@<Finish the reversed...@>=
-begin free_node(p,small_node_size);
-link(t):=q; width(t):=rule_wd; edge_dist(t):=-cur_h-rule_wd; goto done;
-end
-
-@ @<Check for LR anomalies at the end of |s...@>=
-begin if LR_problems>0 then
- begin @<Report LR problems@>; print_char(")"); print_ln;
- end;
-if (LR_ptr<>null)or(cur_dir<>left_to_right) then confusion("LR3");
-@:this can't happen LR3}{\quad LR3@>
-end
-
-@ Some special actions are required for displayed equation in paragraphs
-with mixed direction texts. First of all we have to set the text
-direction preceding the display.
-
-@<Set the value of |x| to the text direction before the display@>=
-if LR_save=null then x:=0
-else if info(LR_save)>=R_code then x:=-1@+else x:=1
-
-@ @<Prepare for display after an empty...@>=
-begin pop_nest; @<Set the value of |x|...@>;
-end
-
-@ When calculating the natural width, |w|, of the final line preceding
-the display, we may have to copy all or part of its hlist. We copy,
-however, only those parts of the original list that are relevant for the
-computation of |pre_display_size|.
-@^data structure assumptions@>
-
-@<Declare subprocedures for |init_math|@>=
-procedure just_copy(@!p,@!h,@!t:pointer);
-label found,not_found;
-var @!r:pointer; {current node being fabricated for new list}
-@!words:0..5; {number of words remaining to be copied}
-begin while p<>null do
- begin words:=1; {this setting occurs in more branches than any other}
- if is_char_node(p) then r:=get_avail
- else case type(p) of
- hlist_node,vlist_node: begin r:=get_node(box_node_size);
- mem[r+6]:=mem[p+6]; mem[r+5]:=mem[p+5]; {copy the last two words}
- words:=5; list_ptr(r):=null; {this affects |mem[r+5]|}
- end;
- rule_node: begin r:=get_node(rule_node_size); words:=rule_node_size;
- end;
- ligature_node: begin r:=get_avail; {only |font| and |character| are needed}
- mem[r]:=mem[lig_char(p)]; goto found;
- end;
- kern_node,math_node: begin r:=get_node(small_node_size);
- words:=small_node_size;
- end;
- glue_node: begin r:=get_node(small_node_size); add_glue_ref(glue_ptr(p));
- glue_ptr(r):=glue_ptr(p); leader_ptr(r):=null;
- end;
- whatsit_node:@<Make a partial copy of the whatsit...@>;
- othercases goto not_found
- endcases;
- while words>0 do
- begin decr(words); mem[r+words]:=mem[p+words];
- end;
- found: link(h):=r; h:=r;
- not_found: p:=link(p);
- end;
-link(h):=t;
-end;
-
-@ When the final line ends with R-text, the value |w| refers to the line
-reflected with respect to the left edge of the enclosing vertical list.
-
-@<Prepare for display after a non-empty...@>=
-if eTeX_ex then @<Let |j| be the prototype box for the display@>;
-v:=shift_amount(just_box);
-@<Set the value of |x|...@>;
-if x>=0 then
- begin p:=list_ptr(just_box); link(temp_head):=null;
- end
-else begin v:=-v-width(just_box);
- p:=new_math(0,begin_L_code); link(temp_head):=p;
- just_copy(list_ptr(just_box),p,new_math(0,end_L_code));
- cur_dir:=right_to_left;
- end;
-v:=v+2*quad(cur_font);
-if TeXXeT_en then @<Initialize the LR stack@>
-
-@ @<Finish the natural width computation@>=
-if TeXXeT_en then
- begin while LR_ptr<>null do pop_LR;
- if LR_problems<>0 then
- begin w:=max_dimen; LR_problems:=0;
- end;
- end;
-cur_dir:=left_to_right; flush_node_list(link(temp_head))
-
-@ In the presence of text direction directives we assume that any LR
-problems have been fixed by the |hpack| routine. If the final line
-contains, however, text direction directives while \TeXXeT\ is disabled,
-then we set |w:=max_dimen|.
-
-@<Cases of `Let |d| be the natural...@>=
-math_node: begin d:=width(p);
- if TeXXeT_en then @<Adjust \(t)the LR stack for the |init_math| routine@>
- else if subtype(p)>=L_code then
- begin w:=max_dimen; goto done;
- end;
- end;
-edge_node: begin d:=width(p); cur_dir:=subtype(p);
- end;
-
-@ @<Adjust \(t)the LR stack for the |i...@>=
-if end_LR(p) then
- begin if info(LR_ptr)=end_LR_type(p) then pop_LR
- else if subtype(p)>L_code then
- begin w:=max_dimen; goto done;
- end
- end
-else begin push_LR(p);
- if LR_dir(p)<>cur_dir then
- begin just_reverse(p); p:=temp_head;
- end;
- end
-
-@ @<Declare subprocedures for |init_math|@>=
-procedure just_reverse(@!p:pointer);
-label found,done;
-var l:pointer; {the new list}
-@!t:pointer; {tail of reversed segment}
-@!q:pointer; {the next node}
-@!m,@!n:halfword; {count of unmatched math nodes}
-begin m:=min_halfword; n:=min_halfword;
-if link(temp_head)=null then
- begin just_copy(link(p),temp_head,null); q:=link(temp_head);
- end
-else begin q:=link(p); link(p):=null; flush_node_list(link(temp_head));
- end;
-t:=new_edge(cur_dir,0); l:=t; cur_dir:=reflected;
-while q<>null do
- if is_char_node(q) then
- repeat p:=q; q:=link(p); link(p):=l; l:=p;
- until not is_char_node(q)
- else begin p:=q; q:=link(p);
- if type(p)=math_node then
- @<Adjust \(t)the LR stack for the |just_reverse| routine@>;
- link(p):=l; l:=p;
- end;
-goto done;
-found:width(t):=width(p); link(t):=q; free_node(p,small_node_size);
-done:link(temp_head):=l;
-end;
-
-@ @<Adjust \(t)the LR stack for the |j...@>=
-if end_LR(p) then
- if info(LR_ptr)<>end_LR_type(p) then
- begin type(p):=kern_node; incr(LR_problems);
- end
- else begin pop_LR;
- if n>min_halfword then
- begin decr(n); decr(subtype(p)); {change |after| into |before|}
- end
- else begin if m>min_halfword then decr(m)@+else goto found;
- type(p):=kern_node;
- end;
- end
-else begin push_LR(p);
- if (n>min_halfword)or(LR_dir(p)<>cur_dir) then
- begin incr(n); incr(subtype(p)); {change |before| into |after|}
- end
- else begin type(p):=kern_node; incr(m);
- end;
- end
-
-@ The prototype box is an hlist node with the width, glue set, and shift
-amount of |just_box|, i.e., the last line preceding the display. Its
-hlist reflects the current \.{\\leftskip} and \.{\\rightskip}.
-
-@<Let |j| be the prototype box for the display@>=
-begin if right_skip=zero_glue then j:=new_kern(0)
-else j:=new_param_glue(right_skip_code);
-if left_skip=zero_glue then p:=new_kern(0)
-else p:=new_param_glue(left_skip_code);
-link(p):=j; j:=new_null_box; width(j):=width(just_box);
-shift_amount(j):=shift_amount(just_box); list_ptr(j):=p;
-glue_order(j):=glue_order(just_box); glue_sign(j):=glue_sign(just_box);
-glue_set(j):=glue_set(just_box);
-end
-
-@ At the end of a displayed equation we retrieve the prototype box.
-
-@<Local variables for finishing...@>=
-@!j:pointer; {prototype box}
-
-@ @<Retrieve the prototype box@>=
-if mode=mmode then j:=LR_box
-
-@ @<Flush the prototype box@>=
-flush_node_list(j)
-
-@ The |app_display| procedure used to append the displayed equation
-and\slash or equation number to the current vertical list has three
-parameters: the prototype box, the hbox to be appended, and the
-displacement of the hbox in the display line.
-
-@<Declare subprocedures for |after_math|@>=
-procedure app_display(@!j,@!b:pointer;@!d:scaled);
-var z:scaled; {width of the line}
-@!s:scaled; {move the line right this much}
-@!e:scaled; {distance from right edge of box to end of line}
-@!x:integer; {|pre_display_direction|}
-@!p,@!q,@!r,@!t,@!u:pointer; {for list manipulation}
-begin s:=display_indent; x:=pre_display_direction;
-if x=0 then shift_amount(b):=s+d
-else begin z:=display_width; p:=b;
- @<Set up the hlist for the display line@>;
- @<Package the display line@>;
- end;
-append_to_vlist(b);
-end;
-
-@ Here we construct the hlist for the display, starting with node |p|
-and ending with node |q|. We also set |d| and |e| to the amount of
-kerning to be added before and after the hlist (adjusted for the
-prototype box).
-
-@<Set up the hlist for the display line@>=
-if x>0 then e:=z-d-width(p)
-else begin e:=d; d:=z-e-width(p);
- end;
-if j<>null then
- begin b:=copy_node_list(j); height(b):=height(p); depth(b):=depth(p);
- s:=s-shift_amount(b); d:=d+s; e:=e+width(b)-z-s;
- end;
-if box_lr(p)=dlist then q:=p {display or equation number}
-else begin {display and equation number}
- r:=list_ptr(p); free_node(p,box_node_size);
- if r=null then confusion("LR4");
- if x>0 then
- begin p:=r;
- repeat q:=r; r:=link(r); {find tail of list}
- until r=null;
- end
- else begin p:=null; q:=r;
- repeat t:=link(r); link(r):=p; p:=r; r:=t; {reverse list}
- until r=null;
- end;
- end
-
-@ In the presence of a prototype box we use its shift amount and width
-to adjust the values of kerning and add these values to the glue nodes
-inserted to cancel the \.{\\leftskip} and \.{\\rightskip}. If there is
-no prototype box (because the display is preceded by an empty
-paragraph), or if the skip parameters are zero, we just add kerns.
-
-The |cancel_glue| macro creates and links a glue node that is, together
-with another glue node, equivalent to a given amount of kerning. We can
-use |j| as temporary pointer, since all we need is |j<>null|.
-
-@d cancel_glue(#)==j:=new_skip_param(#); cancel_glue_cont
-@d cancel_glue_cont(#)==link(#):=j; cancel_glue_cont_cont
-@d cancel_glue_cont_cont(#)==link(j):=#; cancel_glue_end
-@d cancel_glue_end(#)==j:=glue_ptr(#); cancel_glue_end_end
-@d cancel_glue_end_end(#)==
-stretch_order(temp_ptr):=stretch_order(j);
-shrink_order(temp_ptr):=shrink_order(j); width(temp_ptr):=#-width(j);
-stretch(temp_ptr):=-stretch(j); shrink(temp_ptr):=-shrink(j)
-
-@<Package the display line@>=
-if j=null then
- begin r:=new_kern(0); t:=new_kern(0); {the widths will be set later}
- end
-else begin r:=list_ptr(b); t:=link(r);
- end;
-u:=new_math(0,end_M_code);
-if type(t)=glue_node then {|t| is \.{\\rightskip} glue}
- begin cancel_glue(right_skip_code)(q)(u)(t)(e); link(u):=t;
- end
-else begin width(t):=e; link(t):=u; link(q):=t;
- end;
-u:=new_math(0,begin_M_code);
-if type(r)=glue_node then {|r| is \.{\\leftskip} glue}
- begin cancel_glue(left_skip_code)(u)(p)(r)(d); link(r):=u;
- end
-else begin width(r):=d; link(r):=p; link(u):=r;
- if j=null then
- begin b:=hpack(u,natural); shift_amount(b):=s;
- end
- else list_ptr(b):=u;
- end
-
-@ 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 then print_esc("scantokens")
-
-@ @<Cases for |input|@>=
-else if cur_chr=2 then 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...@>=
-@!pseudo_files:pointer; {stack of pseudo files}
-
-@ @<Set init...@>=
-pseudo_files:=null;
-
-@ The |pseudo_start| procedure initiates reading from a pseudo file.
-
-@<Declare \eTeX\ procedures for ex...@>=
-procedure@?pseudo_start; forward;@t\2@>
-
-@ @<Declare \eTeX\ procedures for tok...@>=
-procedure pseudo_start;
-var old_setting:0..max_selector; {holds |selector| setting}
-@!s:str_number; {string to be converted into a pseudo file}
-@!l,@!m:pool_pointer; {indices into |str_pool|}
-@!p,@!q,@!r:pointer; {for list construction}
-@!w: four_quarters; {four ASCII codes}
-@!nl,@!sz:integer;
-begin 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@>;
-end;
-
-@ @<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 do
- begin m:=l;
- while (l<pool_ptr)and(str_pool[l]<>nl) do incr(l);
- sz:=(l-m+7)div 4;
- if sz=1 then sz:=2;
- r:=get_node(sz); link(q):=r; q:=r; info(q):=hi(sz);
- while sz>2 do
- begin 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;
- end;
- w.b0:=qi(" "); w.b1:=qi(" "); w.b2:=qi(" "); w.b3:=qi(" ");
- if l>m then
- begin w.b0:=qi(so(str_pool[m]));
- if l>m+1 then
- begin w.b1:=qi(so(str_pool[m+1]));
- if l>m+2 then
- begin w.b2:=qi(so(str_pool[m+2]));
- if l>m+3 then w.b3:=qi(so(str_pool[m+3]));
- end;
- end;
- end;
- mem[r+1].qqqq:=w;
- if str_pool[l]=nl then incr(l);
- end;
-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 then
- begin if term_offset>max_print_line-3 then print_ln
- else if (term_offset>0)or(file_offset>0) then print_char(" ");
- name:=19; print("( "); incr(open_parens); update_terminal;
- end
-else name:=18
-
-@ Here we read a line from the current pseudo file into |buffer|.
-
-@<Declare \eTeX\ procedures for tr...@>=
-function pseudo_input: boolean; {inputs the next line or returns |false|}
-var p:pointer; {current line from pseudo file}
-@!sz:integer; {size of node |p|}
-@!w:four_quarters; {four ASCII codes}
-@!r:pointer; {loop index}
-begin last:=first; {cf.\ Matthew 19\thinspace:\thinspace30}
-p:=info(pseudo_files);
-if p=null then pseudo_input:=false
-else begin info(pseudo_files):=link(p); sz:=ho(info(p));
- if 4*sz-3>=buf_size-last then
- @<Report overflow of the input buffer, and abort@>;
- last:=first;
- for r:=p+1 to p+sz-1 do
- begin 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;
- end;
- if last>=max_buf_stack then max_buf_stack:=last+1;
- while (last>first)and(buffer[last-1]=" ") do decr(last);
- free_node(p,sz);
- pseudo_input:=true;
- end;
-end;
-
-@ When we are done with a pseudo file we `close' it.
-
-@<Declare \eTeX\ procedures for tr...@>=
-procedure pseudo_close; {close the top level pseudo file}
-var p,@!q: pointer;
-begin p:=link(pseudo_files); q:=info(pseudo_files);
-free_avail(pseudo_files); pseudo_files:=p;
-while q<>null do
- begin p:=q; q:=link(p); free_node(p,ho(info(p)));
- end;
-end;
-
-@ @<Dump the \eTeX\ state@>=
-while pseudo_files<>null do 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 then
- begin while loc<=limit do {current line not yet finished}
- begin cur_chr:=buffer[loc]; incr(loc);
- if cur_chr=" " then cur_tok:=space_token
- @+else cur_tok:=cur_chr+other_token;
- store_new_token(cur_tok);
- end;
- goto done;
- end
-
-@ 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|@>=
-if_def_code:print_esc("ifdefined");
-if_cs_code:print_esc("ifcsname");
-if_font_char_code:print_esc("iffontchar");
-
-@ The result of a boolean condition is reversed when the conditional is
-preceded by \.{\\unless}.
-
-@<Negate a boolean conditional and |goto reswitch|@>=
-begin get_token;
-if (cur_cmd=if_test)and(cur_chr<>if_case_code) then
- begin cur_chr:=cur_chr+unless_code; goto reswitch;
- end;
-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;
-end
-
-@ 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|@>=
-if_def_code:begin save_scanner_status:=scanner_status;
- scanner_status:=normal;
- get_next; b:=(cur_cmd<>undefined_cs);
- scanner_status:=save_scanner_status;
- end;
-
-@ 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|@>=
-if_cs_code:begin n:=get_avail; p:=n; {head of the list of characters}
- repeat get_x_token;
- if cur_cs=0 then store_new_token(cur_tok);
- until cur_cs<>0;
- if cur_cmd<>end_cs_name then @<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);
- end;
-
-@ @<Look up the characters of list |n| in the hash table...@>=
-m:=first; p:=link(n);
-while p<>null do
- begin if m>=max_buf_stack then
- begin max_buf_stack:=m+1;
- if max_buf_stack=buf_size then
- overflow("buffer size",buf_size);
-@:TeX capacity exceeded buffer size}{\quad buffer size@>
- end;
- buffer[m]:=info(p) mod @'400; incr(m); p:=link(p);
- end;
-if m>first+1 then
- cur_cs:=id_lookup(first,m-first) {|no_new_control_sequence| is |true|}
-else if m=first then cur_cs:=null_cs {the list is empty}
-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|@>=
-if_font_char_code:begin scan_font_ident; n:=cur_val; scan_char_num;
- if (font_bc[n]<=cur_val)and(font_ec[n]>=cur_val) then
- b:=char_exists(char_info(n)(qi(cur_val)))
- else b:=false;
- end;
-
-@ 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 then 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...@>=
-procedure get_x_or_protected; {sets |cur_cmd|, |cur_chr|, |cur_tok|,
- and expands non-protected macros}
-label exit;
-begin loop@+begin get_token;
- if cur_cmd<=max_command then return;
- if (cur_cmd>=call)and(cur_cmd<end_template) then
- if info(link(cur_chr))=protected_token then return;
- expand;
- end;
-exit:end;
-
-@ 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...@>=
-@!grp_stack : array[0..max_in_open] of save_pointer; {initial |cur_boundary|}
-@!if_stack : array[0..max_in_open] of pointer; {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...@>=
-procedure group_warning;
-var i:0..max_in_open; {index into |grp_stack|}
-@!w:boolean; {do we need a warning?}
-begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
- {store current state}
-i:=in_open; w:=false;
-while (grp_stack[i]=cur_boundary)and(i>0) do
- begin @<Set variable |w| to indicate if this case should be reported@>;
- grp_stack[i]:=save_index(save_ptr); decr(i);
- end;
-if w then
- begin print_nl("Warning: end of "); print_group(true);
-@.Warning: end of...@>
- print(" of a different file"); print_ln;
- if tracing_nesting>1 then show_context;
- if history=spotless then history:=warning_issued;
- end;
-end;
-
-@ 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 then
- begin while (input_stack[base_ptr].state_field=token_list)or@|
- (input_stack[base_ptr].index_field>i) do decr(base_ptr);
- if input_stack[base_ptr].name_field>17 then w:=true;
- end
-
-@ 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...@>=
-procedure if_warning;
-var i:0..max_in_open; {index into |if_stack|}
-@!w:boolean; {do we need a warning?}
-begin base_ptr:=input_ptr; input_stack[base_ptr]:=cur_input;
- {store current state}
-i:=in_open; w:=false;
-while if_stack[i]=cond_ptr do
- begin @<Set variable |w| to...@>;
- if_stack[i]:=link(cond_ptr); decr(i);
- end;
-if w then
- begin 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 then show_context;
- if history=spotless then history:=warning_issued;
- end;
-end;
-
-@ 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...@>=
-procedure file_warning;
-var p:pointer; {saved value of |save_ptr| or |cond_ptr|}
-@!l:quarterword; {saved value of |cur_level| or |if_limit|}
-@!c:quarterword; {saved value of |cur_group| or |cur_if|}
-@!i:integer; {saved value of |if_line|}
-begin p:=save_ptr; l:=cur_level; c:=cur_group; save_ptr:=cur_boundary;
-while grp_stack[in_open]<>save_ptr do
- begin 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)
- end;
-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 do
- begin print_nl("Warning: end of file when ");
-@.Warning: end of file when...@>
- print_cmd_chr(if_test,cur_if);
- if if_limit=fi_code then 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);
- end;
-cond_ptr:=p; if_limit:=l; cur_if:=c; if_line:=i; {restore old values}
-print_ln;
-if tracing_nesting>1 then show_context;
-if history=spotless then history:=warning_issued;
-end;
-
-@ 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|@>=
-eTeX_expr-int_val+int_val: print_esc("numexpr");
-eTeX_expr-int_val+dimen_val: print_esc("dimexpr");
-eTeX_expr-int_val+glue_val: print_esc("glueexpr");
-eTeX_expr-int_val+mu_val: print_esc("muexpr");
-
-@ 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|@>=
-begin if m<eTeX_mu then
- begin case m of
- @/@<Cases for fetching a glue value@>@/
- end; {there are no other cases}
- cur_val_level:=glue_val;
- end
-else if m<eTeX_expr then
- begin case m of
- @/@<Cases for fetching a mu value@>@/
- end; {there are no other cases}
- cur_val_level:=mu_val;
- end
-else begin cur_val_level:=m-eTeX_expr+int_val; scan_expr;
- end;
-while cur_val_level>level do
- begin if cur_val_level=glue_val then
- begin m:=cur_val; cur_val:=width(m); delete_glue_ref(m);
- end
- else if cur_val_level=mu_val then mu_error;
- decr(cur_val_level);
- end;
-if negative then
- if cur_val_level>=glue_val then
- begin m:=cur_val; cur_val:=new_spec(m); delete_glue_ref(m);
- @<Negate all three glue components of |cur_val|@>;
- end
- else negate(cur_val);
-return;
-end
-
-@ @<Declare \eTeX\ procedures for sc...@>=
-procedure@?scan_expr; forward;@t\2@>
-
-@ The |scan_expr| procedure scans and evaluates an expression.
-
-@<Declare procedures needed for expressions@>=
-@t\4@>@<Declare subprocedures for |scan_expr|@>
-procedure scan_expr; {scans and evaluates an expression}
-label restart, continue, found;
-var a,@!b:boolean; {saved values of |arith_error|}
-@!l:small_number; {type of expression}
-@!r:small_number; {state of expression so far}
-@!s:small_number; {state of term so far}
-@!o:small_number; {next operation or type of next factor}
-@!e:integer; {expression so far}
-@!t:integer; {term so far}
-@!f:integer; {current factor}
-@!n:integer; {numerator of combined multiplication and division}
-@!p:pointer; {top of expression stack}
-@!q:pointer; {for stack manipulations}
-begin l:=cur_val_level; a:=arith_error; b:=false; p:=null;
-incr(expand_depth_count);
-if expand_depth_count>=expand_depth then overflow("expansion depth",expand_depth);
-@<Scan and evaluate an expression |e| of type |l|@>;
-decr(expand_depth_count);
-if b then
- begin 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 then
- begin delete_glue_ref(e); e:=zero_glue; add_glue_ref(e);
- end
- else e:=0;
- end;
-arith_error:=a; cur_val:=e; cur_val_level:=l;
-end;
-
-@ 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;
-continue: if s=expr_none then 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@>;
-case s of @<Cases for evaluation of the current term@>@;
-end; {there are no other cases}
-if o>expr_sub then s:=o@+else @<Evaluate the current expression@>;
-b:=arith_error;
-if o<>expr_none then goto continue;
-if p<>null then @<Pop the expression stack and |goto found|@>
-
-@ @<Scan the next op...@>=
-@<Get the next non-blank non-call token@>;
-if cur_tok=other_token+"+" then o:=expr_add
-else if cur_tok=other_token+"-" then o:=expr_sub
-else if cur_tok=other_token+"*" then o:=expr_mult
-else if cur_tok=other_token+"/" then o:=expr_div
-else begin o:=expr_none;
- if p=null then
- begin if cur_cmd<>relax then back_input;
- end
- else if cur_tok<>other_token+")" then
- begin print_err("Missing ) inserted for expression");
-@.Missing ) inserted@>
- help1("I was expecting to see `+', `-', `*', `/', or `)'. Didn't.");
- back_error;
- end;
- end
-
-@ @<Scan a factor...@>=
-@<Get the next non-blank non-call token@>;
-if cur_tok=other_token+"(" then
- @<Push the expression stack and |goto restart|@>;
-back_input;
-if o=int_val then scan_int
-else if o=dimen_val then scan_normal_dimen
-else if o=glue_val then scan_normal_glue
-else scan_mu_glue;
-f:=cur_val
-
-@ @<Declare \eTeX\ procedures for sc...@>=
-procedure@?scan_normal_glue; forward;@t\2@>@/
-procedure@?scan_mu_glue; forward;@t\2@>
-
-@ Here we declare two trivial procedures in order to avoid mutually
-recursive procedures with parameters.
-
-@<Declare procedures needed for expressions@>=
-procedure scan_normal_glue;
-begin scan_glue(glue_val);
-end;
-@#
-procedure scan_mu_glue;
-begin scan_glue(mu_val);
-end;
-
-@ 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(#)==mem[#+1].int {saved expression so far}
-@d expr_t_field(#)==mem[#+2].int {saved term so far}
-@d expr_n_field(#)==mem[#+3].int {saved numerator}
-
-@<Push the expression...@>=
-begin 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;
-end
-
-@ @<Pop the expression...@>=
-begin f:=e; q:=p;
-e:=expr_e_field(q); t:=expr_t_field(q); n:=expr_n_field(q);
-s:=subtype(q) div 4; r:=subtype(q) mod 4;
-l:=type(q); p:=link(q); free_node(q,expr_node_size);
-goto found;
-end
-
-@ 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(#)== {clear a number or dimension and set |arith_error|}
- begin arith_error:=true; #:=0;
- end
-@d glue_error(#)== {clear a glue spec and set |arith_error|}
- begin arith_error:=true; delete_glue_ref(#); #:=new_spec(zero_glue);
- end
-
-@<Make sure that |f|...@>=
-if (l=int_val)or(s>expr_sub) then
- begin if (f>infinity)or(f<-infinity) then num_error(f);
- end
-else if l=dimen_val then
- begin if abs(f)>max_dimen then num_error(f);
- end
-else begin if (abs(width(f))>max_dimen)or@|
- (abs(stretch(f))>max_dimen)or@|
- (abs(shrink(f))>max_dimen) then glue_error(f);
- end
-
-@ 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(#)==
- if stretch(#)=0 then stretch_order(#):=normal;
- if shrink(#)=0 then shrink_order(#):=normal
-
-@<Cases for evaluation of the current term@>=
-expr_none: if (l>=glue_val)and(o<>expr_none) then
- begin t:=new_spec(f); delete_glue_ref(f); normalize_glue(t);
- end
- else t:=f;
-
-@ When a term |t| has been completed it is copied to, added to, or
-subtracted from the expression |e|.
-
-@d expr_add_sub(#)==add_or_sub(#,r=expr_sub)
-@d expr_a(#)==expr_add_sub(#,max_dimen)
-
-@<Evaluate the current expression@>=
-begin s:=expr_none;
-if r=expr_none then e:=t
-else if l=int_val then e:=expr_add_sub(e,t,infinity)
-else if l=dimen_val then e:=expr_a(e,t)
-else @<Compute the sum or difference of two glue specs@>;
-r:=o;
-end
-
-@ 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|@>=
-function add_or_sub(@!x,@!y,@!max_answer:integer;@!negative:boolean):integer;
-var a:integer; {the answer}
-begin if negative then negate(y);
-if x>=0 then
- if y<=max_answer-x then a:=x+y@+else num_error(a)
-else if y>=-max_answer-x then a:=x+y@+else num_error(a);
-add_or_sub:=a;
-end;
-
-@ 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...@>=
-begin width(e):=expr_a(width(e),width(t));
-if stretch_order(e)=stretch_order(t) then
- stretch(e):=expr_a(stretch(e),stretch(t))
-else if (stretch_order(e)<stretch_order(t))and(stretch(t)<>0) then
- begin stretch(e):=stretch(t); stretch_order(e):=stretch_order(t);
- end;
-if shrink_order(e)=shrink_order(t) then
- shrink(e):=expr_a(shrink(e),shrink(t))
-else if (shrink_order(e)<shrink_order(t))and(shrink(t)<>0) then
- begin shrink(e):=shrink(t); shrink_order(e):=shrink_order(t);
- end;
-delete_glue_ref(t); normalize_glue(e);
-end
-
-@ 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(#)==#:=nx_plus_y(#,f,0)
-
-@<Cases for evaluation of the current term@>=
-expr_mult: if o=expr_div then
- begin n:=f; o:=expr_scale;
- end
- else if l=int_val then t:=mult_integers(t,f)
- else if l=dimen_val then expr_m(t)
- else begin expr_m(width(t)); expr_m(stretch(t)); expr_m(shrink(t));
- end;
-
-@ Here we divide the term |t| by the factor |f|.
-
-@d expr_d(#)==#:=quotient(#,f)
-
-@<Cases for evaluation of the current term@>=
-expr_div: if l<glue_val then expr_d(t)
- else begin expr_d(width(t)); expr_d(stretch(t)); expr_d(shrink(t));
- end;
-
-@ 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|@>=
-function quotient(@!n,@!d:integer):integer;
-var negative:boolean; {should the answer be negated?}
-@!a:integer; {the answer}
-begin if d=0 then num_error(a)
-else begin if d>0 then negative:=false
- else begin negate(d); negative:=true;
- end;
- if n<0 then
- begin negate(n); negative:=not negative;
- end;
- a:=n div d; n:=n-a*d; d:=n-d; {avoid certain compiler optimizations!}
- if d+n>=0 then incr(a);
- if negative then negate(a);
- end;
-quotient:=a;
-end;
-
-@ Here the term |t| is multiplied by the quotient $n/f$.
-
-@d expr_s(#)==#:=fract(#,n,f,max_dimen)
-
-@<Cases for evaluation of the current term@>=
-expr_scale: if l=int_val then t:=fract(t,n,f,infinity)
- else if l=dimen_val then expr_s(t)
- else begin expr_s(width(t)); expr_s(stretch(t)); expr_s(shrink(t));
- end;
-
-@ 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.
-
-@d too_big=88 {go here when the result is too big}
-
-@<Declare subprocedures for |scan_expr|@>=
-function fract(@!x,@!n,@!d,@!max_answer:integer):integer;
-label found, found1, too_big, done;
-var negative:boolean; {should the answer be negated?}
-@!a:integer; {the answer}
-@!f:integer; {a proper fraction}
-@!h:integer; {smallest integer such that |2*h>=d|}
-@!r:integer; {intermediate remainder}
-@!t:integer; {temp variable}
-begin if d=0 then goto too_big;
-a:=0;
-if d>0 then negative:=false
-else begin negate(d); negative:=true;
- end;
-if x<0 then
- begin negate(x); negative:=not negative;
- end
-else if x=0 then goto done;
-if n<0 then
- begin negate(n); negative:=not negative;
- end;
-t:=n div d;
-if t>max_answer div x then goto too_big;
-a:=t*x; n:=n-t*d;
-if n=0 then goto found;
-t:=x div d;
-if t>(max_answer-a) div n then goto too_big;
-a:=a+t*n; x:=x-t*d;
-if x=0 then goto found;
-if x<n then
- begin t:=x; x:=n; n:=t;
- end; {now |0<n<=x<d|}
-@<Compute \(f)$f=\lfloor xn/d+{1\over2}\rfloor$@>@;
-if f>(max_answer-a) then goto too_big;
-a:=a+f;
-found: if negative then negate(a);
-goto done;
-too_big: num_error(a);
-done: fract:=a;
-end;
-
-@ 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 div 2)-d; h:=-r;
-loop@+begin if odd(n) then
- begin r:=r+x;
- if r>=0 then
- begin r:=r-d; incr(f);
- end;
- end;
- n:=n div 2;
- if n=0 then goto found1;
- if x<h then x:=x+x
- else begin t:=x-d; x:=t+x; f:=f+n;
- if x<n then
- begin if x=0 then goto found1;
- t:=x; x:=n; n:=t;
- end;
- end;
- end;
-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|@>=
-glue_stretch_order_code: print_esc("gluestretchorder");
-glue_shrink_order_code: print_esc("glueshrinkorder");
-glue_stretch_code: print_esc("gluestretch");
-glue_shrink_code: print_esc("glueshrink");
-
-@ @<Cases for fetching an integer value@>=
-glue_stretch_order_code, glue_shrink_order_code:
- begin scan_normal_glue; q:=cur_val;
- if m=glue_stretch_order_code then cur_val:=stretch_order(q)
- else cur_val:=shrink_order(q);
- delete_glue_ref(q);
- end;
-
-@ @<Cases for fetching a dimension value@>=
-glue_stretch_code, glue_shrink_code:
- begin scan_normal_glue; q:=cur_val;
- if m=glue_stretch_code then cur_val:=stretch(q)
- else cur_val:=shrink(q);
- delete_glue_ref(q);
- end;
-
-@ 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|@>=
-mu_to_glue_code: print_esc("mutoglue");
-glue_to_mu_code: print_esc("gluetomu");
-
-@ @<Cases for fetching a glue value@>=
-mu_to_glue_code: scan_mu_glue;
-
-@ @<Cases for fetching a mu value@>=
-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).
-
-Similarly there are 32768 mark classes; the command \.{\\marks}|n|
-creates a mark node for a given mark class |0<=n<=32767| (where
-\.{\\marks0} is synonymous to \.{\\mark}). The page builder (actually
-the |fire_up| routine) and the |vsplit| routine maintain the current
-values of |top_mark|, |first_mark|, |bot_mark|, |split_first_mark|, and
-|split_bot_mark| for each mark class. They are accessed as
-\.{\\topmarks}|n| etc., and \.{\\topmarks0} is again synonymous to
-\.{\\topmark}. As in \TeX\ the five current marks for mark class zero
-are realized as |cur_mark| array. The additional current marks are
-again realized as tree structure with individual mark classes existing
-only when needed.
-
-@<Generate all \eTeX...@>=
-primitive("marks",mark,marks_code);
-@!@:marks_}{\.{\\marks} primitive@>
-primitive("topmarks",top_bot_mark,top_mark_code+marks_code);
-@!@:top_marks_}{\.{\\topmarks} primitive@>
-primitive("firstmarks",top_bot_mark,first_mark_code+marks_code);
-@!@:first_marks_}{\.{\\firstmarks} primitive@>
-primitive("botmarks",top_bot_mark,bot_mark_code+marks_code);
-@!@:bot_marks_}{\.{\\botmarks} primitive@>
-primitive("splitfirstmarks",top_bot_mark,split_first_mark_code+marks_code);
-@!@:split_first_marks_}{\.{\\splitfirstmarks} primitive@>
-primitive("splitbotmarks",top_bot_mark,split_bot_mark_code+marks_code);
-@!@:split_bot_marks_}{\.{\\splitbotmarks} primitive@>
-
-@ 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...@>=
-procedure@?scan_register_num; forward;@t\2@>
-
-@ @<Declare procedures that scan restricted classes of integers@>=
-procedure scan_register_num;
-begin scan_int;
-if (cur_val<0)or(cur_val>max_reg_num) then
- begin 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;
- end;
-end;
-
-@ @<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...@>=
-@!max_reg_num: halfword; {largest allowed register number}
-@!max_reg_help_line: str_number; {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=@"20 {$2^4\cdot(|dimen_val|+1)$}
-@d mu_val_limit=@"40 {$2^4\cdot(|mu_val|+1)$}
-@d box_val_limit=@"50 {$2^4\cdot(|box_val|+1)$}
-@d tok_val_limit=@"60 {$2^4\cdot(|tok_val|+1)$}
-@#
-@d index_node_size=9 {size of an index node}
-@d sa_index==type {a four-bit address or a type or both}
-@d sa_used==subtype {count of non-null pointers}
-
-@<Declare \eTeX\ procedures for ex...@>=
-procedure new_index(@!i:quarterword; @!q:pointer);
-var k:small_number; {loop index}
-begin cur_ptr:=get_node(index_node_size); sa_index(cur_ptr):=i;
-sa_used(cur_ptr):=0; link(cur_ptr):=q;
-for k:=1 to index_node_size-1 do {clear all 16 pointers}
- mem[cur_ptr+k]:=sa_null;
-end;
-
-@ 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...@>=
-@!sa_root:array[int_val..mark_val] of pointer; {roots of sparse arrays}
-@!cur_ptr:pointer; {value returned by |new_index| and |find_sa_element|}
-@!sa_null:memory_word; {two |null| pointers}
-
-@ @<Set init...@>=
-sa_mark:=null; sa_null.hh.lh:=null; sa_null.hh.rh:=null;
-
-@ @<Initialize table...@>=
-for i:=int_val to tok_val do 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(#)== {some tree element is missing}
- begin if cur_ptr=null then
- if w then goto #@+else return;
- end
-@#
-@d hex_dig1(#)==# div 4096 {the fourth lowest hexadecimal digit}
-@d hex_dig2(#)==(# div 256) mod 16 {the third lowest hexadecimal digit}
-@d hex_dig3(#)==(# div 16) mod 16 {the second lowest hexadecimal digit}
-@d hex_dig4(#)==# mod 16 {the lowest hexadecimal digit}
-@#
-@d get_sa_ptr==if odd(i) then cur_ptr:=link(q+(i div 2)+1)
- else cur_ptr:=info(q+(i div 2)+1)
- {set |cur_ptr| to the pointer indexed by |i| from index node |q|}
-@d put_sa_ptr(#)==if odd(i) then link(q+(i div 2)+1):=#
- else info(q+(i div 2)+1):=#
- {store the pointer indexed by |i| in index node |q|}
-@d add_sa_ptr==begin put_sa_ptr(cur_ptr); incr(sa_used(q));
- end {add |cur_ptr| as the pointer indexed by |i| in index node |q|}
-@d delete_sa_ptr==begin put_sa_ptr(null); decr(sa_used(q));
- end {delete the pointer indexed by |i| in index node |q|}
-
-@<Declare \eTeX\ procedures for ex...@>=
-procedure find_sa_element(@!t:small_number;@!n:halfword;@!w:boolean);
- {sets |cur_val| to sparse array element location or |null|}
-label not_found,not_found1,not_found2,not_found3,not_found4,exit;
-var q:pointer; {for list manipulations}
-@!i:small_number; {a four bit index}
-begin 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)and w then 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;
-exit:end;
-
-@ 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(#)==(sa_index(#) div 16) {type part of combined type/index}
-@d sa_ref(#)==info(#+1) {reference count of a sparse array element}
-@d sa_ptr(#)==link(#+1) {a pointer value}
-@#
-@d word_node_size=3 {size of an element with a word value}
-@d sa_num==sa_ptr {the register number}
-@d sa_int(#)==mem[#+2].int {an integer}
-@d sa_dim(#)==mem[#+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(#)== {fetch |box(cur_val)|}
- if cur_val<256 then #:=box(cur_val)
- else begin find_sa_element(box_val,cur_val,false);
- if cur_ptr=null then #:=null@+else #:=sa_ptr(cur_ptr);
- end
-
-@<Create a new array element...@>=
-if t=mark_val then {a mark class}
- begin 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;
- end
-else begin if t<=dimen_val then {a count or dimen register}
- begin cur_ptr:=get_node(word_node_size); sa_int(cur_ptr):=0;
- sa_num(cur_ptr):=n;
- end
- else begin cur_ptr:=get_node(pointer_node_size);
- if t<=mu_val then {a skip or muskip register}
- begin sa_ptr(cur_ptr):=zero_glue; add_glue_ref(zero_glue);
- end
- else sa_ptr(cur_ptr):=null; {a box or token list register}
- end;
- sa_ref(cur_ptr):=null; {all registers have a reference count}
- end;
-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(#)==incr(sa_ref(#)) {increase reference count}
-@#
-@d change_box(#)== {change |box(cur_val)|, the |eq_level| stays the same}
- if cur_val<256 then box(cur_val):=#@+else set_sa_box(#)
-@#
-@d set_sa_box(#)==begin find_sa_element(box_val,cur_val,false);
- if cur_ptr<>null then
- begin sa_ptr(cur_ptr):=#; add_sa_ref(cur_ptr); delete_sa_ref(cur_ptr);
- end;
- end
-
-@<Declare \eTeX\ procedures for tr...@>=
-procedure delete_sa_ref(@!q:pointer); {reduce reference count}
-label exit;
-var p:pointer; {for list manipulations}
-@!i:small_number; {a four bit index}
-@!s:small_number; {size of a node}
-begin decr(sa_ref(q));
-if sa_ref(q)<>null then return;
-if sa_index(q)<dimen_val_limit then
- if sa_int(q)=0 then s:=word_node_size
- else return
-else begin if sa_index(q)<mu_val_limit then
- if sa_ptr(q)=zero_glue then delete_glue_ref(zero_glue)
- else return
- else if sa_ptr(q)<>null then return;
- s:=pointer_node_size;
- end;
-repeat i:=hex_dig4(sa_index(q)); p:=q; q:=link(p); free_node(p,s);
-if q=null then {the whole tree has been freed}
- begin sa_root[i]:=null; return;
- end;
-delete_sa_ptr; s:=index_node_size; {node |q| is an index node}
-until sa_used(q)>0;
-exit:end;
-
-@ The |print_sa_num| procedure prints the register number corresponding
-to an array element.
-
-@<Basic print...@>=
-procedure print_sa_num(@!q:pointer); {print register number}
-var @!n:halfword; {the register number}
-begin if sa_index(q)<dimen_val_limit then n:=sa_num(q) {the easy case}
-else begin 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)));
- end;
-print_int(n);
-end;
-
-@ 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...@>=
-@!stat procedure show_sa(@!p:pointer;@!s:str_number);
-var t:small_number; {the type of element}
-begin begin_diagnostic; print_char("{"); print(s); print_char(" ");
-if p=null then print_char("?") {this can't happen}
-else begin t:=sa_type(p);
- if t<box_val then print_cmd_chr(register,p)
- else if t=box_val then
- begin print_esc("box"); print_sa_num(p);
- end
- else if t=tok_val then print_cmd_chr(toks_register,p)
- else print_char("?"); {this can't happen either}
- print_char("=");
- if t=int_val then print_int(sa_int(p))
- else if t=dimen_val then
- begin print_scaled(sa_dim(p)); print("pt");
- end
- else begin p:=sa_ptr(p);
- if t=glue_val then print_spec(p,"pt")
- else if t=mu_val then print_spec(p,"mu")
- else if t=box_val then
- if p=null then print("void")
- else begin depth_threshold:=0; breadth_max:=1; show_node_list(p);
- end
- else if t=tok_val then
- begin if p<>null then show_token_list(link(p),null,32);
- end
- else print_char("?"); {this can't happen either}
- end;
- end;
-print_char("}"); end_diagnostic(false);
-end;
-tats
-
-@ Here we compute the pointer to the current mark of type |t| and mark
-class |cur_val|.
-
-@<Compute the mark pointer...@>=
-begin find_sa_element(mark_val,cur_val,false);
-if cur_ptr<>null then
- if odd(t) then cur_ptr:=link(cur_ptr+(t div 2)+1)
- else cur_ptr:=info(cur_ptr+(t div 2)+1);
-end
-
-@ The current marks for all mark classes are maintained by the |vsplit|
-and |fire_up| routines and are finally destroyed (for \.{INITEX} only)
-@.INITEX@>
-by the |final_cleanup| routine. Apart from updating the current marks
-when mark nodes are encountered, these routines perform certain actions
-on all existing mark classes. The recursive |do_marks| procedure walks
-through the whole tree or a subtree of existing mark class nodes and
-preforms certain actions indicted by its first parameter |a|, the action
-code. The second parameter |l| indicates the level of recursion (at
-most four); the third parameter points to a nonempty tree or subtree.
-The result is |true| if the complete tree or subtree has been deleted.
-
-@d vsplit_init==0 {action code for |vsplit| initialization}
-@d fire_up_init==1 {action code for |fire_up| initialization}
-@d fire_up_done==2 {action code for |fire_up| completion}
-@d destroy_marks==3 {action code for |final_cleanup|}
-@#
-@d sa_top_mark(#)==info(#+1) {\.{\\topmarks}|n|}
-@d sa_first_mark(#)==link(#+1) {\.{\\firstmarks}|n|}
-@d sa_bot_mark(#)==info(#+2) {\.{\\botmarks}|n|}
-@d sa_split_first_mark(#)==link(#+2) {\.{\\splitfirstmarks}|n|}
-@d sa_split_bot_mark(#)==info(#+3) {\.{\\splitbotmarks}|n|}
-
-@<Declare the function called |do_marks|@>=
-function do_marks(@!a,@!l:small_number;@!q:pointer):boolean;
-var i:small_number; {a four bit index}
-begin if l<4 then {|q| is an index node}
- begin for i:=0 to 15 do
- begin get_sa_ptr;
- if cur_ptr<>null then if do_marks(a,l+1,cur_ptr) then delete_sa_ptr;
- end;
- if sa_used(q)=0 then
- begin free_node(q,index_node_size); q:=null;
- end;
- end
-else {|q| is the node for a mark class}
- begin case a of
- @<Cases for |do_marks|@>@;
- end; {there are no other cases}
- if sa_bot_mark(q)=null then if sa_split_bot_mark(q)=null then
- begin free_node(q,mark_class_node_size); q:=null;
- end;
- end;
-do_marks:=(q=null);
-end;
-
-@ At the start of the |vsplit| routine the existing |split_fist_mark|
-and |split_bot_mark| are discarded.
-
-@<Cases for |do_marks|@>=
-vsplit_init: if sa_split_first_mark(q)<>null then
- begin delete_token_ref(sa_split_first_mark(q)); sa_split_first_mark(q):=null;
- delete_token_ref(sa_split_bot_mark(q)); sa_split_bot_mark(q):=null;
- end;
-
-@ We use again the fact that |split_first_mark=null| if and only if
-|split_bot_mark=null|.
-
-@<Update the current marks for |vsplit|@>=
-begin find_sa_element(mark_val,mark_class(p),true);
-if sa_split_first_mark(cur_ptr)=null then
- begin sa_split_first_mark(cur_ptr):=mark_ptr(p);
- add_token_ref(mark_ptr(p));
- end
-else delete_token_ref(sa_split_bot_mark(cur_ptr));
-sa_split_bot_mark(cur_ptr):=mark_ptr(p);
-add_token_ref(mark_ptr(p));
-end
-
-@ At the start of the |fire_up| routine the old |top_mark| and
-|first_mark| are discarded, whereas the old |bot_mark| becomes the new
-|top_mark|. An empty new |top_mark| token list is, however, discarded
-as well in order that mark class nodes can eventually be released. We
-use again the fact that |bot_mark<>null| implies |first_mark<>null|; it
-also knows that |bot_mark=null| implies |top_mark=first_mark=null|.
-
-@<Cases for |do_marks|@>=
-fire_up_init: if sa_bot_mark(q)<>null then
- begin if sa_top_mark(q)<>null then delete_token_ref(sa_top_mark(q));
- delete_token_ref(sa_first_mark(q)); sa_first_mark(q):=null;
- if link(sa_bot_mark(q))=null then {an empty token list}
- begin delete_token_ref(sa_bot_mark(q)); sa_bot_mark(q):=null;
- end
- else add_token_ref(sa_bot_mark(q));
- sa_top_mark(q):=sa_bot_mark(q);
- end;
-
-@ @<Cases for |do_marks|@>=
-fire_up_done: if (sa_top_mark(q)<>null)and(sa_first_mark(q)=null) then
- begin sa_first_mark(q):=sa_top_mark(q); add_token_ref(sa_top_mark(q));
- end;
-
-@ @<Update the current marks for |fire_up|@>=
-begin find_sa_element(mark_val,mark_class(p),true);
-if sa_first_mark(cur_ptr)=null then
- begin sa_first_mark(cur_ptr):=mark_ptr(p);
- add_token_ref(mark_ptr(p));
- end;
-if sa_bot_mark(cur_ptr)<>null then delete_token_ref(sa_bot_mark(cur_ptr));
-sa_bot_mark(cur_ptr):=mark_ptr(p); add_token_ref(mark_ptr(p));
-end
-
-@ Here we use the fact that the five current mark pointers in a mark
-class node occupy the same locations as the the first five pointers of
-an index node. For systems using a run-time switch to distinguish
-between \.{VIRTEX} and \.{INITEX}, the codewords `$|init|\ldots|tini|$'
-surrounding the following piece of code should be removed.
-@.INITEX@>
-@^system dependencies@>
-
-@<Cases for |do_marks|@>=
-@!init destroy_marks: for i:=top_mark_code to split_bot_mark_code do
- begin get_sa_ptr;
- if cur_ptr<>null then
- begin delete_token_ref(cur_ptr); put_sa_ptr(null);
- end;
- end;
-tini
-
-@ The command code |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|@>=
-begin if (chr_code<mem_bot)or(chr_code>lo_mem_stat_max) then
- cmd:=sa_type(chr_code)
-else begin cmd:=chr_code-mem_bot; chr_code:=null;
- end;
-if cmd=int_val then print_esc("count")
-else if cmd=dimen_val then print_esc("dimen")
-else if cmd=glue_val then print_esc("skip")
-else print_esc("muskip");
-if chr_code<>null then print_sa_num(chr_code);
-end
-
-@ 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|@>=
-begin print_esc("toks");
-if chr_code<>mem_bot then print_sa_num(chr_code);
-end
-
-@ 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|@>=
-toks_register,register:
- if (equiv_field(w)<mem_bot)or(equiv_field(w)>lo_mem_stat_max) then
- delete_sa_ref(equiv_field(w));
-
-@ 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...@>=
-@!sa_chain: pointer; {chain of saved sparse array entries}
-@!sa_level: quarterword; {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==sa_ref {location of saved item}
-
-@<Declare \eTeX\ procedures for tr...@>=
-procedure sa_save(@!p:pointer); {saves value of |p|}
-var q:pointer; {the new save node}
-@!i:quarterword; {index field of node}
-begin if cur_level<>sa_level then
- begin 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;
- end;
-i:=sa_index(p);
-if i<dimen_val_limit then
- begin if sa_int(p)=0 then
- begin q:=get_node(pointer_node_size); i:=tok_val_limit;
- end
- else begin q:=get_node(word_node_size); sa_int(q):=sa_int(p);
- end;
- sa_ptr(q):=null;
- end
-else begin q:=get_node(pointer_node_size); sa_ptr(q):=sa_ptr(p);
- end;
-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);
-end;
-
-@ @<Declare \eTeX\ procedures for tr...@>=
-procedure sa_destroy(@!p:pointer); {destroy value of |p|}
-begin if sa_index(p)<mu_val_limit then delete_glue_ref(sa_ptr(p))
-else if sa_ptr(p)<>null then
- if sa_index(p)<box_val_limit then flush_node_list(sa_ptr(p))
- else delete_token_ref(sa_ptr(p));
-end;
-
-@ 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(#)==if e then
- if global then gsa_def(#)@+else sa_def(#)
- else define
-@#
-@d sa_def_box== {assign |cur_box| to |box(cur_val)|}
- begin find_sa_element(box_val,cur_val,true);
- if global then gsa_def(cur_ptr,cur_box)@+else sa_def(cur_ptr,cur_box);
- end
-@#
-@d sa_word_define(#)==if e then
- if global then gsa_w_def(#)@+else sa_w_def(#)
- else word_define(#)
-
-@<Declare \eTeX\ procedures for tr...@>=
-procedure sa_def(@!p:pointer;@!e:halfword);
- {new data for sparse array elements}
-begin add_sa_ref(p);
-if sa_ptr(p)=e then
- begin @!stat if tracing_assigns>0 then show_sa(p,"reassigning");@+tats@;@/
- sa_destroy(p);
- end
-else begin @!stat if tracing_assigns>0 then show_sa(p,"changing");@+tats@;@/
- if sa_lev(p)=cur_level then sa_destroy(p)@+else sa_save(p);
- sa_lev(p):=cur_level; sa_ptr(p):=e;
- @!stat if tracing_assigns>0 then show_sa(p,"into");@+tats@;@/
- end;
-delete_sa_ref(p);
-end;
-@#
-procedure sa_w_def(@!p:pointer;@!w:integer);
-begin add_sa_ref(p);
-if sa_int(p)=w then
- begin @!stat if tracing_assigns>0 then show_sa(p,"reassigning");@+tats@;@/
- end
-else begin @!stat if tracing_assigns>0 then show_sa(p,"changing");@+tats@;@/
- if sa_lev(p)<>cur_level then sa_save(p);
- sa_lev(p):=cur_level; sa_int(p):=w;
- @!stat if tracing_assigns>0 then show_sa(p,"into");@+tats@;@/
- end;
-delete_sa_ref(p);
-end;
-
-@ 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...@>=
-procedure gsa_def(@!p:pointer;@!e:halfword); {global |sa_def|}
-begin add_sa_ref(p);
-@!stat if tracing_assigns>0 then show_sa(p,"globally changing");@+tats@;@/
-sa_destroy(p); sa_lev(p):=level_one; sa_ptr(p):=e;
-@!stat if tracing_assigns>0 then show_sa(p,"into");@+tats@;@/
-delete_sa_ref(p);
-end;
-@#
-procedure gsa_w_def(@!p:pointer;@!w:integer); {global |sa_w_def|}
-begin add_sa_ref(p);
-@!stat if tracing_assigns>0 then show_sa(p,"globally changing");@+tats@;@/
-sa_lev(p):=level_one; sa_int(p):=w;
-@!stat if tracing_assigns>0 then show_sa(p,"into");@+tats@;@/
-delete_sa_ref(p);
-end;
-
-@ The |sa_restore| procedure restores the sparse array entries pointed
-at by |sa_chain|
-
-@<Declare \eTeX\ procedures for tr...@>=
-procedure sa_restore;
-var p:pointer; {sparse array element}
-begin repeat p:=sa_loc(sa_chain);
-if sa_lev(p)=level_one then
- begin if sa_index(p)>=dimen_val_limit then sa_destroy(sa_chain);
- @!stat if tracing_restores>0 then show_sa(p,"retaining");@+tats@;@/
- end
-else begin if sa_index(p)<dimen_val_limit then
- if sa_index(sa_chain)<dimen_val_limit then sa_int(p):=sa_int(sa_chain)
- else sa_int(p):=0
- else begin sa_destroy(p); sa_ptr(p):=sa_ptr(sa_chain);
- end;
- sa_lev(p):=sa_lev(sa_chain);
- @!stat if tracing_restores>0 then show_sa(p,"restoring");@+tats@;@/
- end;
-delete_sa_ref(p);
-p:=sa_chain; sa_chain:=link(p);
-if sa_index(p)<dimen_val_limit then free_node(p,word_node_size)
-else free_node(p,pointer_node_size);
-until sa_chain=null;
-end;
-
-@ When the value of |last_line_fit| is positive, the last line of a
-(partial) paragraph is treated in a special way and we need additional
-fields in the active nodes.
-
-@d active_node_size_extended=5 {number of words in extended active nodes}
-@d active_short(#)==mem[#+3].sc {|shortfall| of this line}
-@d active_glue(#)==mem[#+4].sc {corresponding glue stretch or shrink}
-
-@<Glob...@>=
-@!last_line_fill:pointer; {the |par_fill_skip| glue node of the new paragraph}
-@!do_last_line_fit:boolean; {special algorithm for last line of paragraph?}
-@!active_node_size:small_number; {number of words in active nodes}
-@!fill_width:array[0..2] of scaled; {infinite stretch components of
- |par_fill_skip|}
-@!best_pl_short:array[very_loose_fit..tight_fit] of scaled; {|shortfall|
- corresponding to |minimal_demerits|}
-@!best_pl_glue:array[very_loose_fit..tight_fit] of scaled; {corresponding
- glue stretch or shrink}
-
-@ The new algorithm for the last line requires that the stretchability of
-|par_fill_skip| is infinite and the stretchability of |left_skip| plus
-|right_skip| is finite.
-
-@<Check for special...@>=
-do_last_line_fit:=false; active_node_size:=active_node_size_normal;
- {just in case}
-if last_line_fit>0 then
- begin q:=glue_ptr(last_line_fill);
- if (stretch(q)>0)and(stretch_order(q)>normal) then
- if (background[3]=0)and(background[4]=0)and(background[5]=0) then
- begin do_last_line_fit:=true;
- active_node_size:=active_node_size_extended;
- fill_width[0]:=0; fill_width[1]:=0; fill_width[2]:=0;
- fill_width[stretch_order(q)-1]:=stretch(q);
- end;
- end
-
-@ @<Other local variables for |try_break|@>=
-@!g:scaled; {glue stretch or shrink of test line, adjustment for last line}
-
-@ Here we initialize the additional fields of the first active node
-representing the beginning of the paragraph.
-
-@<Initialize additional fields of the first active node@>=
-begin active_short(q):=0; active_glue(q):=0;
-end
-
-@ Here we compute the adjustment |g| and badness |b| for a line from |r|
-to the end of the paragraph. When any of the criteria for adjustment is
-violated we fall through to the normal algorithm.
-
-The last line must be too short, and have infinite stretch entirely due
-to |par_fill_skip|.
-
-@<Perform computations for last line and |goto found|@>=
-begin if (active_short(r)=0)or(active_glue(r)<=0) then goto not_found;
- {previous line was neither stretched nor shrunk, or was infinitely bad}
-if (cur_active_width[3]<>fill_width[0])or@|
- (cur_active_width[4]<>fill_width[1])or@|
- (cur_active_width[5]<>fill_width[2]) then goto not_found;
- {infinite stretch of this line not entirely due to |par_fill_skip|}
-if active_short(r)>0 then g:=cur_active_width[2]
-else g:=cur_active_width[6];
-if g<=0 then goto not_found; {no finite stretch resp.\ no shrink}
-arith_error:=false; g:=fract(g,active_short(r),active_glue(r),max_dimen);
-if last_line_fit<1000 then g:=fract(g,last_line_fit,1000,max_dimen);
-if arith_error then
- if active_short(r)>0 then g:=max_dimen@+else g:=-max_dimen;
-if g>0 then
- @<Set the value of |b| to the badness of the last line for stretching,
- compute the corresponding |fit_class|, and |goto found|@>
-else if g<0 then
- @<Set the value of |b| to the badness of the last line for shrinking,
- compute the corresponding |fit_class|, and |goto found|@>;
-not_found:end
-
-@ These badness computations are rather similar to those of the standard
-algorithm, with the adjustment amount |g| replacing the |shortfall|.
-
-@<Set the value of |b| to the badness of the last line for str...@>=
-begin if g>shortfall then g:=shortfall;
-if g>7230584 then if cur_active_width[2]<1663497 then
- begin b:=inf_bad; fit_class:=very_loose_fit; goto found;
- end;
-b:=badness(g,cur_active_width[2]);
-if b>12 then
- if b>99 then fit_class:=very_loose_fit
- else fit_class:=loose_fit
-else fit_class:=decent_fit;
-goto found;
-end
-
-@ @<Set the value of |b| to the badness of the last line for shr...@>=
-begin if -g>cur_active_width[6] then g:=-cur_active_width[6];
-b:=badness(-g,cur_active_width[6]);
-if b>12 then fit_class:=tight_fit@+else fit_class:=decent_fit;
-goto found;
-end
-
-@ Vanishing values of |shortfall| and |g| indicate that the last line is
-not adjusted.
-
-@<Adjust \(t)the additional data for last line@>=
-begin if cur_p=null then shortfall:=0;
-if shortfall>0 then g:=cur_active_width[2]
-else if shortfall<0 then g:=cur_active_width[6]
-else g:=0;
-end
-
-@ For each feasible break we record the shortfall and glue stretch or
-shrink (or adjustment).
-
-@<Store \(a)additional data for this feasible break@>=
-begin best_pl_short[fit_class]:=shortfall; best_pl_glue[fit_class]:=g;
-end
-
-@ Here we save these data in the active node representing a potential
-line break.
-
-@<Store \(a)additional data in the new active node@>=
-begin active_short(q):=best_pl_short[fit_class];
-active_glue(q):=best_pl_glue[fit_class];
-end
-
-@ @<Print additional data in the new active node@>=
-begin print(" s="); print_scaled(active_short(q));
-if cur_p=null then print(" a=")@+else print(" g=");
-print_scaled(active_glue(q));
-end
-
-@ Here we either reset |do_last_line_fit| or adjust the |par_fill_skip|
-glue.
-
-@<Adjust \(t)the final line of the paragraph@>=
-if active_short(best_bet)=0 then do_last_line_fit:=false
-else begin q:=new_spec(glue_ptr(last_line_fill));
- delete_glue_ref(glue_ptr(last_line_fill));
- width(q):=width(q)+active_short(best_bet)-active_glue(best_bet);
- stretch(q):=0; glue_ptr(last_line_fill):=q;
- end
-
-@ When reading \.{\\patterns} while \.{\\savinghyphcodes} is positive
-the current |lc_code| values are stored together with the hyphenation
-patterns for the current language. They will later be used instead of
-the |lc_code| values for hyphenation purposes.
-
-The |lc_code| values are stored in the linked trie analogous to patterns
-$p_1$ of length~1, with |hyph_root=trie_r[0]| replacing |trie_root| and
-|lc_code(p_1)| replacing the |trie_op| code. This allows to compress
-and pack them together with the patterns with minimal changes to the
-existing code.
-
-@d hyph_root==trie_r[0] {root of the linked trie for |hyph_codes|}
-
-@<Initialize table entries...@>=
-hyph_root:=0; hyph_start:=0;
-
-@ @<Store hyphenation codes for current language@>=
-begin c:=cur_lang; first_child:=false; p:=0;
-repeat q:=p; p:=trie_r[q];
-until (p=0)or(c<=so(trie_c[p]));
-if (p=0)or(c<so(trie_c[p])) then
- @<Insert a new trie node between |q| and |p|, and
- make |p| point to it@>;
-q:=p; {now node |q| represents |cur_lang|}
-@<Store all current |lc_code| values@>;
-end
-
-@ We store all nonzero |lc_code| values, overwriting any previously
-stored values (and possibly wasting a few trie nodes that were used
-previously and are not needed now). We always store at least one
-|lc_code| value such that |hyph_index| (defined below) will not be zero.
-
-@<Store all current |lc_code| values@>=
-p:=trie_l[q]; first_child:=true;
-for c:=0 to 255 do
- if (lc_code(c)>0)or((c=255)and first_child) then
- begin if p=0 then
- @<Insert a new trie node between |q| and |p|, and
- make |p| point to it@>
- else trie_c[p]:=si(c);
- trie_o[p]:=qi(lc_code(c));
- q:=p; p:=trie_r[q]; first_child:=false;
- end;
-if first_child then trie_l[q]:=0@+else trie_r[q]:=0
-
-@ We must avoid to ``take'' location~1, in order to distinguish between
-|lc_code| values and patterns.
-
-@<Pack all stored |hyph_codes|@>=
-begin if trie_root=0 then for p:=0 to 255 do trie_min[p]:=p+2;
-first_fit(hyph_root); trie_pack(hyph_root);
-hyph_start:=trie_ref[hyph_root];
-end
-
-@ The global variable |hyph_index| will point to the hyphenation codes
-for the current language.
-
-@d set_hyph_index== {set |hyph_index| for current language}
- if trie_char(hyph_start+cur_lang)<>qi(cur_lang)
- then hyph_index:=0 {no hyphenation codes for |cur_lang|}
- else hyph_index:=trie_link(hyph_start+cur_lang)
-@#
-@d set_lc_code(#)== {set |hc[0]| to hyphenation or lc code for |#|}
- if hyph_index=0 then hc[0]:=lc_code(#)
- else if trie_char(hyph_index+#)<>qi(#) then hc[0]:=0
- else hc[0]:=qo(trie_op(hyph_index+#))
-
-@<Glob...@>=
-@!hyph_start:trie_pointer; {root of the packed trie for |hyph_codes|}
-@!hyph_index:trie_pointer; {pointer to hyphenation codes for |cur_lang|}
-
-@ When |saving_vdiscards| is positive then the glue, kern, and penalty
-nodes removed by the page builder or by \.{\\vsplit} from the top of a
-vertical list are saved in special lists instead of being discarded.
-
-@d tail_page_disc==disc_ptr[copy_code] {last item removed by page builder}
-@d page_disc==disc_ptr[last_box_code] {first item removed by page builder}
-@d split_disc==disc_ptr[vsplit_code] {first item removed by \.{\\vsplit}}
-
-@<Glob...@>=
-@!disc_ptr:array[copy_code..vsplit_code] of pointer; {list pointers}
-
-@ @<Set init...@>=
-page_disc:=null; split_disc:=null;
-
-@ The \.{\\pagediscards} and \.{\\splitdiscards} commands share the
-command code |un_vbox| with \.{\\unvbox} and \.{\\unvcopy}, they are
-distinguished by their |chr_code| values |last_box_code| and
-|vsplit_code|. These |chr_code| values are larger than |box_code| and
-|copy_code|.
-
-@<Generate all \eTeX...@>=
-primitive("pagediscards",un_vbox,last_box_code);@/
-@!@:page_discards_}{\.{\\pagediscards} primitive@>
-primitive("splitdiscards",un_vbox,vsplit_code);@/
-@!@:split_discards_}{\.{\\splitdiscards} primitive@>
-
-@ @<Cases of |un_vbox| for |print_cmd_chr|@>=
-else if chr_code=last_box_code then print_esc("pagediscards")
-else if chr_code=vsplit_code then print_esc("splitdiscards")
-
-@ @<Handle saved items and |goto done|@>=
-begin link(tail):=disc_ptr[cur_chr]; disc_ptr[cur_chr]:=null;
-goto done;
-end
-
-@ 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)
-@d club_penalties_ptr==equiv(club_penalties_loc)
-@d widow_penalties_ptr==equiv(widow_penalties_loc)
-@d display_widow_penalties_ptr==equiv(display_widow_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|@>=
-inter_line_penalties_loc: print_esc("interlinepenalties");
-club_penalties_loc: print_esc("clubpenalties");
-widow_penalties_loc: print_esc("widowpenalties");
-display_widow_penalties_loc: print_esc("displaywidowpenalties");
-
-@ @<Fetch a penalties array element@>=
-begin scan_int;
-if (equiv(m)=null)or(cur_val<0) then cur_val:=0
-else begin if cur_val>penalty(equiv(m)) then cur_val:=penalty(equiv(m));
- cur_val:=penalty(equiv(m)+cur_val);
- end;
-end
-
-@* \[54] System-dependent changes.
-@z
-%---------------------------------------