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authorLuigi Scarso <luigi.scarso@gmail.com>2018-09-05 21:57:30 +0000
committerLuigi Scarso <luigi.scarso@gmail.com>2018-09-05 21:57:30 +0000
commitecd1605a23ef54d2a4a69e1a361172d350e03b3b (patch)
tree8ea1d9745c24dbc5e755f13d801fa01e88944650 /Build/source/texk/web2c/luatexdir/tex/align.w
parent04563248956e7059aad4fc4f6bf7da18562f7b8c (diff)
luatex: correct automake file for pplib; replaced cweb files with c files.
git-svn-id: svn://tug.org/texlive/trunk@48594 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/texk/web2c/luatexdir/tex/align.w')
-rw-r--r--Build/source/texk/web2c/luatexdir/tex/align.w1144
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diff --git a/Build/source/texk/web2c/luatexdir/tex/align.w b/Build/source/texk/web2c/luatexdir/tex/align.w
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@@ -1,1144 +0,0 @@
-% align.w
-%
-% Copyright 2009-2010 Taco Hoekwater <taco@@luatex.org>
-%
-% This file is part of LuaTeX.
-%
-% LuaTeX is free software; you can redistribute it and/or modify it under
-% the terms of the GNU General Public License as published by the Free
-% Software Foundation; either version 2 of the License, or (at your
-% option) any later version.
-%
-% LuaTeX is distributed in the hope that it will be useful, but WITHOUT
-% ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-% FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
-% License for more details.
-%
-% You should have received a copy of the GNU General Public License along
-% with LuaTeX; if not, see <http://www.gnu.org/licenses/>.
-
-\def\<#1>{$#1$}
-
-@ @c
-
-
-#include "ptexlib.h"
-
-@ @c
-void fin_align(void);
-void init_row(void);
-void init_col(void);
-
-#define noDEBUG
-
-@ It's sort of a miracle whenever \.{\\halign} and \.{\\valign} work, because
-they cut across so many of the control structures of \TeX.
-
-Therefore the present page is probably not the best place for a beginner to
-start reading this program; it is better to master everything else first.
-
-Let us focus our thoughts on an example of what the input might be, in order
-to get some idea about how the alignment miracle happens. The example doesn't
-do anything useful, but it is sufficiently general to indicate all of the
-special cases that must be dealt with; please do not be disturbed by its
-apparent complexity and meaninglessness.
-$$\vbox{\halign{\.{#}\hfil\cr
-{}\\tabskip 2pt plus 3pt\cr
-{}\\halign to 300pt\{u1\#v1\&\cr
-\hskip 50pt\\tabskip 1pt plus 1fil u2\#v2\&\cr
-\hskip 50pt u3\#v3\\cr\cr
-\hskip 25pt a1\&\\omit a2\&\\vrule\\cr\cr
-\hskip 25pt \\noalign\{\\vskip 3pt\}\cr
-\hskip 25pt b1\\span b2\\cr\cr
-\hskip 25pt \\omit\&c2\\span\\omit\\cr\}\cr}}$$
-Here's what happens:
-
-\yskip
-(0) When `\.{\\halign to 300pt\{}' is scanned, the |scan_spec| routine
-places the 300pt dimension onto the |save_stack|, and an |align_group|
-code is placed above it. This will make it possible to complete the alignment
-when the matching `\.\}' is found.
-
-(1) The preamble is scanned next. Macros in the preamble are not expanded,
-@^preamble@>
-except as part of a tabskip specification. For example, if \.{u2} had been
-a macro in the preamble above, it would have been expanded, since \TeX\
-must look for `\.{minus...}' as part of the tabskip glue. A ``preamble list''
-is constructed based on the user's preamble; in our case it contains the
-following seven items:
-$$\vbox{\halign{\.{#}\hfil\qquad&(#)\hfil\cr
-{}\\glue 2pt plus 3pt&the tabskip preceding column 1\cr
-{}\\alignrecord, width $-\infty$&preamble info for column 1\cr
-{}\\glue 2pt plus 3pt&the tabskip between columns 1 and 2\cr
-{}\\alignrecord, width $-\infty$&preamble info for column 2\cr
-{}\\glue 1pt plus 1fil&the tabskip between columns 2 and 3\cr
-{}\\alignrecord, width $-\infty$&preamble info for column 3\cr
-{}\\glue 1pt plus 1fil&the tabskip following column 3\cr}}$$
-These ``alignrecord'' entries have the same size as an |unset_node|,
-since they will later be converted into such nodes. These alignrecord
-nodes have no |depth| field; this is split into |u_part| and |v_part|,
-and they point to token lists for the templates of the alignment. For
-example, the |u_part| field in the first alignrecord points to the
-token list `\.{u1}', i.e., the template preceding the `\.\#' for
-column~1. Furthermore, They have a |span_ptr| instead of a |node_attr|
-field, and these |span_ptr| fields are initially set to the value
-|end_span|, for reasons explained below.
-
-(2) \TeX\ now looks at what follows the \.{\\cr} that ended the preamble.
-It is not `\.{\\noalign}' or `\.{\\omit}', so this input is put back to
-be read again, and the template `\.{u1}' is fed to the scanner. Just
-before reading `\.{u1}', \TeX\ goes into restricted horizontal mode.
-Just after reading `\.{u1}', \TeX\ will see `\.{a1}', and then (when the
-{\.\&} is sensed) \TeX\ will see `\.{v1}'. Then \TeX\ scans an |endv|
-token, indicating the end of a column. At this point an |unset_node| is
-created, containing the contents of the current hlist (i.e., `\.{u1a1v1}').
-The natural width of this unset node replaces the |width| field of the
-alignrecord for column~1; in general, the alignrecords will record the
-maximum natural width that has occurred so far in a given column.
-
-(3) Since `\.{\\omit}' follows the `\.\&', the templates for column~2
-are now bypassed. Again \TeX\ goes into restricted horizontal mode and
-makes an |unset_node| from the resulting hlist; but this time the
-hlist contains simply `\.{a2}'. The natural width of the new unset box
-is remembered in the |width| field of the alignrecord for column~2.
-
-(4) A third |unset_node| is created for column 3, using essentially the
-mechanism that worked for column~1; this unset box contains `\.{u3\\vrule
-v3}'. The vertical rule in this case has running dimensions that will later
-extend to the height and depth of the whole first row, since each |unset_node|
-in a row will eventually inherit the height and depth of its enclosing box.
-
-(5) The first row has now ended; it is made into a single unset box
-comprising the following seven items:
-$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
-{}\\glue 2pt plus 3pt\cr
-{}\\unsetbox for 1 column: u1a1v1\cr
-{}\\glue 2pt plus 3pt\cr
-{}\\unsetbox for 1 column: a2\cr
-{}\\glue 1pt plus 1fil\cr
-{}\\unsetbox for 1 column: u3\\vrule v3\cr
-{}\\glue 1pt plus 1fil\cr}}$$
-The width of this unset row is unimportant, but it has the correct height
-and depth, so the correct baselineskip glue will be computed as the row
-is inserted into a vertical list.
-
-(6) Since `\.{\\noalign}' follows the current \.{\\cr}, \TeX\ appends
-additional material (in this case \.{\\vskip 3pt}) to the vertical list.
-While processing this material, \TeX\ will be in internal vertical
-mode, and |no_align_group| will be on |save_stack|.
-
-(7) The next row produces an unset box that looks like this:
-$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
-{}\\glue 2pt plus 3pt\cr
-{}\\unsetbox for 2 columns: u1b1v1u2b2v2\cr
-{}\\glue 1pt plus 1fil\cr
-{}\\unsetbox for 1 column: {\rm(empty)}\cr
-{}\\glue 1pt plus 1fil\cr}}$$
-The natural width of the unset box that spans columns 1~and~2 is stored
-in a ``span node,'' which we will explain later; the |span_ptr| field of the
-alignrecord for column~1 now points to the new span node, and the |span_ptr|
-of the span node points to |end_span|.
-
-(8) The final row produces the unset box
-$$\vbox{\halign{\hbox to 325pt{\qquad\.{#}\hfil}\cr
-{}\\glue 2pt plus 3pt\cr
-{}\\unsetbox for 1 column: {\rm(empty)}\cr
-{}\\glue 2pt plus 3pt\cr
-{}\\unsetbox for 2 columns: u2c2v2\cr
-{}\\glue 1pt plus 1fil\cr}}$$
-A new span node is attached to the alignrecord for column 2.
-
-(9) The last step is to compute the true column widths and to change all the
-unset boxes to hboxes, appending the whole works to the vertical list that
-encloses the \.{\\halign}. The rules for deciding on the final widths of
-each unset column box will be explained below.
-
-\yskip\noindent
-Note that as \.{\\halign} is being processed, we fearlessly give up control
-to the rest of \TeX. At critical junctures, an alignment routine is
-called upon to step in and do some little action, but most of the time
-these routines just lurk in the background. It's something like
-post-hypnotic suggestion.
-
-@ We have mentioned that alignrecords contain no |height| or |depth| fields.
-Their |glue_sign| and |glue_order| are pre-empted as well, since it
-is necessary to store information about what to do when a template ends.
-This information is called the |extra_info| field.
-
-@c
-/* could be in texnodes.h, but documented here*/
-
-#define u_part(A) vlink((A)+depth_offset) /* pointer to \<u_j> token list */
-#define v_part(A) vinfo((A)+depth_offset) /* pointer to \<v_j> token list */
-#define span_ptr(A) vinfo((A)+1) /* column spanning list */
-#define extra_info(A) vinfo((A)+list_offset) /* info to remember during template */
-
-@ Alignments can occur within alignments, so a small stack is used to access
-the alignrecord information. At each level we have a |preamble| pointer,
-indicating the beginning of the preamble list; a |cur_align| pointer,
-indicating the current position in the preamble list; a |cur_span| pointer,
-indicating the value of |cur_align| at the beginning of a sequence of
-spanned columns; a |cur_loop| pointer, indicating the tabskip glue before
-an alignrecord that should be copied next if the current list is extended;
-and the |align_state| variable, which indicates the nesting of braces so
-that \.{\\cr} and \.{\\span} and tab marks are properly intercepted.
-There also are pointers |cur_head| and |cur_tail| to the head and tail
-of a list of adjustments being moved out from horizontal mode to
-vertical~mode, and alike |cur_pre_head| and |cur_pre_tail| for pre-adjust
-lists.
-
-The current values of these nine quantities appear in global variables;
-when they have to be pushed down, they are stored in 6-word nodes, and
-|align_ptr| points to the topmost such node.
-
-@c
-/* could be in texnodes.h but documented here*/
-
-#define preamble vlink(align_head) /* the current preamble list */
-
-pointer cur_align = null; /* current position in preamble list */
-pointer cur_span = null; /* start of currently spanned columns in preamble list */
-pointer cur_loop = null; /* place to copy when extending a periodic preamble */
-pointer align_ptr = null; /* most recently pushed-down alignment stack node */
-pointer cur_head = null, cur_tail = null; /* adjustment list pointers */
-pointer cur_pre_head = null, cur_pre_tail = null; /* pre-adjustment list pointers */
-
-/* The |align_state| and |preamble| variables are initialized elsewhere. */
-
-@ Alignment stack maintenance is handled by a pair of trivial routines
-called |push_alignment| and |pop_alignment|.
-
-(HH:) It makes not much sense to add support for an \.{attr} keyword to
-\.{\\halign} and \.{\\valign} because then we need to decide if we tag
-rows or cells or both or come up with \.{cellattr} and \.{rowattr} and
-such. But then it even makes sense to have explicit commands (in addition
-to the seperator) to tags individual cells. Too muss hassle for now and the
-advantages are not that large.
-
-@c
-static void push_alignment(void)
-{
- pointer p; /* the new alignment stack node */
- p = new_node(align_stack_node, 0);
- vinfo(p + 1) = align_ptr;
- vlink(p + 1) = cur_align;
- vinfo(p + 2) = preamble;
- vlink(p + 2) = cur_span;
- vinfo(p + 3) = cur_loop;
- vlink(p + 3) = align_state;
- vinfo(p + 4) = cur_head;
- vlink(p + 4) = cur_tail;
- vinfo(p + 5) = cur_pre_head;
- vlink(p + 5) = cur_pre_tail;
- align_ptr = p;
- cur_head = new_node(temp_node, 0);
- cur_pre_head = new_node(temp_node, 0);
-}
-
-static void pop_alignment(void)
-{
- pointer p; /* the top alignment stack node */
- flush_node(cur_head);
- flush_node(cur_pre_head);
- p = align_ptr;
- cur_pre_tail = vlink(p + 5);
- cur_pre_head = vinfo(p + 5);
- cur_tail = vlink(p + 4);
- cur_head = vinfo(p + 4);
- align_state = vlink(p + 3);
- cur_loop = vinfo(p + 3);
- cur_span = vlink(p + 2);
- preamble = vinfo(p + 2);
- cur_align = vlink(p + 1);
- align_ptr = vinfo(p + 1);
- flush_node(p);
-}
-
-
-@ \TeX\ has eight procedures that govern alignments: |init_align| and
-|fin_align| are used at the very beginning and the very end; |init_row| and
-|fin_row| are used at the beginning and end of individual rows; |init_span|
-is used at the beginning of a sequence of spanned columns (possibly involving
-only one column); |init_col| and |fin_col| are used at the beginning and
-end of individual columns; and |align_peek| is used after \.{\\cr} to see
-whether the next item is \.{\\noalign}.
-
-We shall consider these routines in the order they are first used during
-the course of a complete \.{\\halign}, namely |init_align|, |align_peek|,
-|init_row|, |init_span|, |init_col|, |fin_col|, |fin_row|, |fin_align|.
-
-
-@ The preamble is copied directly, except that \.{\\tabskip} causes a change
-to the tabskip glue, thereby possibly expanding macros that immediately
-follow it. An appearance of \.{\\span} also causes such an expansion.
-
-Note that if the preamble contains `\.{\\global\\tabskip}', the `\.{\\global}'
-token survives in the preamble and the `\.{\\tabskip}' defines new
-tabskip glue (locally).
-
-@c
-static void get_preamble_token(void)
-{
- RESTART:
- get_token();
- while ((cur_chr == span_code) && (cur_cmd == tab_mark_cmd)) {
- get_token(); /* this token will be expanded once */
- if (cur_cmd > max_command_cmd) {
- expand();
- get_token();
- }
- }
- if (cur_cmd == endv_cmd)
- fatal_error("(interwoven alignment preambles are not allowed)");
- if ((cur_cmd == assign_glue_cmd)
- && (cur_chr == glue_base + tab_skip_code)) {
- scan_optional_equals();
- scan_glue(glue_val_level);
- if (global_defs_par > 0)
- geq_define(glue_base + tab_skip_code, glue_ref_cmd, cur_val);
- else
- eq_define(glue_base + tab_skip_code, glue_ref_cmd, cur_val);
- goto RESTART;
- }
-}
-
-
-
-@ When \.{\\halign} or \.{\\valign} has been scanned in an appropriate
-mode, \TeX\ calls |init_align|, whose task is to get everything off to a
-good start. This mostly involves scanning the preamble and putting its
-information into the preamble list.
-@^preamble@>
-
-@c
-void init_align(void)
-{
- /* label done, done1, done2, continue; */
- pointer save_cs_ptr; /* |warning_index| value for error messages */
- pointer p, r; /* for short-term temporary use */
- save_cs_ptr = cur_cs; /* \.{\\halign} or \.{\\valign}, usually */
- push_alignment();
- align_state = -1000000; /* enter a new alignment level */
-
- /* When \.{\\halign} is used as a displayed formula, there should be
- no other pieces of mlists present. */
-
- if ((cur_list.mode_field == mmode)
- && ((cur_list.tail_field != cur_list.head_field)
- || (incompleat_noad_par != null))) {
- const char *hlp[] =
- { "Displays can use special alignments (like \\eqalignno)",
- "only if nothing but the alignment itself is between $$'s.",
- "So I've deleted the formulas that preceded this alignment.",
- NULL
- };
- tex_error("Improper \\halign inside $$'s", hlp);
- flush_math();
- }
- push_nest(); /* enter a new semantic level */
- /* In vertical modes, |prev_depth| already has the correct value. But
- if we are in |mmode| (displayed formula mode), we reach out to the
- enclosing vertical mode for the |prev_depth| value that produces the
- correct baseline calculations. */
- if (cur_list.mode_field == mmode) {
- cur_list.mode_field = -vmode;
- prev_depth_par = nest[nest_ptr - 2].prev_depth_field;
- } else if (cur_list.mode_field > 0) {
- cur_list.mode_field = -(cur_list.mode_field);
- }
- scan_spec(align_group);
- /* Scan the preamble */
- preamble = null;
- cur_align = align_head;
- cur_loop = null;
- scanner_status = aligning;
- warning_index = save_cs_ptr;
- align_state = -1000000;
- /* at this point, |cur_cmd=left_brace| */
- while (true) {
- /* Append the current tabskip glue to the preamble list */
- r = new_param_glue(tab_skip_code);
- vlink(cur_align) = r;
- cur_align = vlink(cur_align);
-
- if (cur_cmd == car_ret_cmd)
- break; /* \.{\\cr} ends the preamble */
-
- /* Scan preamble text until |cur_cmd| is |tab_mark| or |car_ret| */
- /* Scan the template \<u_j>, putting the resulting token list in |hold_token_head| */
- /* Spaces are eliminated from the beginning of a template. */
-
- p = hold_token_head;
- token_link(p) = null;
- while (1) {
- get_preamble_token();
- if (cur_cmd == mac_param_cmd)
- break;
- if ((cur_cmd <= car_ret_cmd) && (cur_cmd >= tab_mark_cmd)
- && (align_state == -1000000)) {
- if ((p == hold_token_head) && (cur_loop == null)
- && (cur_cmd == tab_mark_cmd)) {
- cur_loop = cur_align;
- } else {
- const char *hlp[] =
- { "There should be exactly one # between &'s, when an",
- "\\halign or \\valign is being set up. In this case you had",
- "none, so I've put one in; maybe that will work.",
- NULL
- };
- back_input();
- tex_error("Missing # inserted in alignment preamble", hlp);
- break;
- }
- } else if ((cur_cmd != spacer_cmd) || (p != hold_token_head)) {
- r = get_avail();
- token_link(p) = r;
- p = token_link(p);
- token_info(p) = cur_tok;
- }
- }
- r = new_node(align_record_node, 0);
- vlink(cur_align) = r;
- cur_align = vlink(cur_align); /* a new alignrecord */
- span_ptr(cur_align) = end_span;
- width(cur_align) = null_flag;
- u_part(cur_align) = token_link(hold_token_head);
- /* Scan the template \<v_j>, putting the resulting token list in |hold_token_head| */
-
- p = hold_token_head;
- token_link(p) = null;
- while (1) {
- CONTINUE:
- get_preamble_token();
- if ((cur_cmd <= car_ret_cmd) && (cur_cmd >= tab_mark_cmd)
- && (align_state == -1000000))
- break;
- if (cur_cmd == mac_param_cmd) {
- const char *hlp[] =
- { "There should be exactly one # between &'s, when an",
- "\\halign or \\valign is being set up. In this case you had",
- "more than one, so I'm ignoring all but the first.",
- NULL
- };
- tex_error("Only one # is allowed per tab", hlp);
- goto CONTINUE;
- }
- r = get_avail();
- token_link(p) = r;
- p = token_link(p);
- token_info(p) = cur_tok;
- }
- r = get_avail();
- token_link(p) = r;
- p = token_link(p);
- token_info(p) = end_template_token; /* put \.{\\endtemplate} at the end */
-
- v_part(cur_align) = token_link(hold_token_head);
- }
- scanner_status = normal;
-
- new_save_level(align_group);
- if (every_cr_par != null)
- begin_token_list(every_cr_par, every_cr_text);
- align_peek(); /* look for \.{\\noalign} or \.{\\omit} */
-}
-
-
-@ The tricky part about alignments is getting the templates into the
-scanner at the right time, and recovering control when a row or column
-is finished.
-
-We usually begin a row after each \.{\\cr} has been sensed, unless that
-\.{\\cr} is followed by \.{\\noalign} or by the right brace that terminates
-the alignment. The |align_peek| routine is used to look ahead and do
-the right thing; it either gets a new row started, or gets a \.{\\noalign}
-started, or finishes off the alignment.
-
-@c
-void align_peek(void)
-{
- RESTART:
- align_state = 1000000;
- do {
- get_x_or_protected();
- } while (cur_cmd == spacer_cmd);
- if (cur_cmd == no_align_cmd) {
- scan_left_brace();
- new_save_level(no_align_group);
- if (cur_list.mode_field == -vmode)
- normal_paragraph();
- } else if (cur_cmd == right_brace_cmd) {
- fin_align();
- } else if ((cur_cmd == car_ret_cmd) && (cur_chr == cr_cr_code)) {
- goto RESTART; /* ignore \.{\\crcr} */
- } else {
- init_row(); /* start a new row */
- init_col(); /* start a new column and replace what we peeked at */
- }
-}
-
-
-@ The parameter to |init_span| is a pointer to the alignrecord where the
-next column or group of columns will begin. A new semantic level is
-entered, so that the columns will generate a list for subsequent packaging.
-
-@c
-static void init_span(pointer p)
-{
- push_nest();
- if (cur_list.mode_field == -hmode) {
- space_factor_par = 1000;
- } else {
- prev_depth_par = ignore_depth;
- normal_paragraph();
- }
- cur_span = p;
-}
-
-
-@ To start a row (i.e., a `row' that rhymes with `dough' but not with `bough'),
-we enter a new semantic level, copy the first tabskip glue, and change
-from internal vertical mode to restricted horizontal mode or vice versa.
-The |space_factor| and |prev_depth| are not used on this semantic level,
-but we clear them to zero just to be tidy.
-
-@c
-void init_row(void)
-{
- push_nest();
- cur_list.mode_field = (-hmode - vmode) - cur_list.mode_field;
- if (cur_list.mode_field == -hmode)
- space_factor_par = 0;
- else
- prev_depth_par = 0;
- tail_append(new_glue(preamble));
- subtype(cur_list.tail_field) = tab_skip_code + 1;
- cur_align = vlink(preamble);
- cur_tail = cur_head;
- cur_pre_tail = cur_pre_head;
- init_span(cur_align);
-}
-
-
-@ When a column begins, we assume that |cur_cmd| is either |omit| or else
-the current token should be put back into the input until the \<u_j>
-template has been scanned. (Note that |cur_cmd| might be |tab_mark| or
-|car_ret|.) We also assume that |align_state| is approximately 1000000 at
-this time. We remain in the same mode, and start the template if it is
-called for.
-
-@c
-void init_col(void)
-{
- extra_info(cur_align) = cur_cmd;
- if (cur_cmd == omit_cmd)
- align_state = 0;
- else {
- back_input();
- begin_token_list(u_part(cur_align), u_template);
- } /* now |align_state=1000000| */
-}
-
-
-@ The scanner sets |align_state| to zero when the \<u_j> template ends. When
-a subsequent \.{\\cr} or \.{\\span} or tab mark occurs with |align_state=0|,
-the scanner activates the following code, which fires up the \<v_j> template.
-We need to remember the |cur_chr|, which is either |cr_cr_code|, |cr_code|,
-|span_code|, or a character code, depending on how the column text has ended.
-
-This part of the program had better not be activated when the preamble
-to another alignment is being scanned, or when no alignment preamble is active.
-
-@c
-void insert_vj_template(void)
-{
- if ((scanner_status == aligning) || (cur_align == null))
- fatal_error("(interwoven alignment preambles are not allowed)");
- cur_cmd = extra_info(cur_align);
- extra_info(cur_align) = cur_chr;
- if (cur_cmd == omit_cmd)
- begin_token_list(omit_template, v_template);
- else
- begin_token_list(v_part(cur_align), v_template);
- align_state = 1000000;
-}
-
-/* Determine the stretch order */
-#define determine_stretch_order() do { \
- if (total_stretch[filll]!=0) o=filll; \
- else if (total_stretch[fill]!=0) o=fill; \
- else if (total_stretch[fil]!=0) o=fil; \
- else if (total_stretch[sfi]!=0) o=sfi; \
- else o=normal; \
- } while (0)
-
-
-/* Determine the shrink order */
-#define determine_shrink_order() do { \
- if (total_shrink[filll]!=0) o=filll; \
- else if (total_shrink[fill]!=0) o=fill; \
- else if (total_shrink[fil]!=0) o=fil; \
- else if (total_shrink[sfi]!=0) o=sfi; \
- else o=normal; \
- } while (0)
-
-
-
-@ When the |endv| command at the end of a \<v_j> template comes through the
-scanner, things really start to happen; and it is the |fin_col| routine
-that makes them happen. This routine returns |true| if a row as well as a
-column has been finished.
-
-@c
-boolean fin_col(void)
-{
- pointer p; /* the alignrecord after the current one */
- pointer q, r; /* temporary pointers for list manipulation */
- pointer s; /* a new span node */
- pointer u; /* a new unset box */
- scaled w; /* natural width */
- unsigned char o; /* order of infinity */
- halfword n; /* span counter */
- if (cur_align == null)
- confusion("endv");
- q = vlink(cur_align);
- if (q == null)
- confusion("endv");
- if (align_state < 500000)
- fatal_error("(interwoven alignment preambles are not allowed)");
- p = vlink(q);
- /* If the preamble list has been traversed, check that the row has ended */
- if ((p == null) && (extra_info(cur_align) < cr_code)) {
- if (cur_loop != null) {
- /* Lengthen the preamble periodically */
- r = new_node(align_record_node, 0);
- vlink(q) = r;
- p = vlink(q); /* a new alignrecord */
- span_ptr(p) = end_span;
- width(p) = null_flag;
- cur_loop = vlink(cur_loop);
-
- /* Copy the templates from node |cur_loop| into node |p| */
- q = hold_token_head;
- r = u_part(cur_loop);
- while (r != null) {
- s = get_avail();
- token_link(q) = s;
- q = token_link(q);
- token_info(q) = token_info(r);
- r = token_link(r);
- }
- token_link(q) = null;
- u_part(p) = token_link(hold_token_head);
- q = hold_token_head;
- r = v_part(cur_loop);
- while (r != null) {
- s = get_avail();
- token_link(q) = s;
- q = token_link(q);
- token_info(q) = token_info(r);
- r = token_link(r);
- }
- token_link(q) = null;
- v_part(p) = token_link(hold_token_head);
-
- cur_loop = vlink(cur_loop);
- r = new_glue(cur_loop);
- vlink(p) = r;
- } else {
- const char *hlp[] =
- { "You have given more \\span or & marks than there were",
- "in the preamble to the \\halign or \\valign now in progress.",
- "So I'll assume that you meant to type \\cr instead.",
- NULL
- };
- extra_info(cur_align) = cr_code;
- tex_error("Extra alignment tab has been changed to \\cr", hlp);
- }
- }
- if (extra_info(cur_align) != span_code) {
- unsave();
- new_save_level(align_group);
- /* Package an unset box for the current column and record its width */
- if (cur_list.mode_field == -hmode) {
- adjust_tail = cur_tail;
- pre_adjust_tail = cur_pre_tail;
- u = filtered_hpack(cur_list.head_field, cur_list.tail_field, 0,
- additional, align_set_group, -1, 0, 0);
- w = width(u);
- cur_tail = adjust_tail;
- adjust_tail = null;
- cur_pre_tail = pre_adjust_tail;
- pre_adjust_tail = null;
- } else {
- u = filtered_vpackage(vlink(cur_list.head_field),
- 0, additional, 0, align_set_group, -1, 0, 0);
- w = height(u);
- }
- n = min_quarterword; /* this represents a span count of 1 */
- if (cur_span != cur_align) {
- /* Update width entry for spanned columns */
- q = cur_span;
- do {
- incr(n);
- q = vlink(vlink(q));
- } while (q != cur_align);
- if (n > max_quarterword)
- confusion("too many spans"); /* this can happen, but won't */
- q = cur_span;
- while (span_span(span_ptr(q)) < n) {
- q = span_ptr(q);
- }
- if (span_span(span_ptr(q)) > n) {
- s = new_span_node(span_ptr(q), n, w);
- span_ptr(q) = s;
- } else if (width(span_ptr(q)) < w) {
- width(span_ptr(q)) = w;
- }
-
- } else if (w > width(cur_align)) {
- width(cur_align) = w;
- }
- type(u) = unset_node;
- span_count(u) = (quarterword) n;
- determine_stretch_order();
- glue_order(u) = o;
- glue_stretch(u) = total_stretch[o];
- determine_shrink_order();
- glue_sign(u) = o;
- glue_shrink(u) = total_shrink[o];
- pop_nest();
- vlink(cur_list.tail_field) = u;
- cur_list.tail_field = u;
-
- /* Copy the tabskip glue between columns */
- tail_append(new_glue(vlink(cur_align)));
- subtype(cur_list.tail_field) = tab_skip_code + 1;
-
- if (extra_info(cur_align) >= cr_code) {
- return true;
- }
- init_span(p);
- }
- align_state = 1000000;
- do {
- get_x_or_protected();
- } while (cur_cmd == spacer_cmd);
- cur_align = p;
- init_col();
- return false;
-}
-
-
-
-@ A span node is a 3-word record containing |width|, |span_span|, and
-|span_ptr| fields. The |span_span| field indicates the number of
-spanned columns; the |span_ptr| field points to a span node for the same
-starting column, having a greater extent of spanning, or to
-|end_span|, which has the largest possible |span_span| field; the |width|
-field holds the largest natural width corresponding to a particular
-set of spanned columns.
-
-A list of the maximum widths so far, for spanned columns starting at a
-given column, begins with the |span_ptr| field of the alignrecord for
-that column. The code has to make sure that there is room for
-|span_ptr| in both the alignrecord and the span nodes, which is why
-|span_ptr| replaces |node_attr|.
-@^data structure assumptions@>
-
-The |new_span_node| function is defined in |texnodes.c|.
-
-@c
-#ifndef span_span
-# define span_span(A) vlink((A)+1) /* that is normally |alink| */
-#endif
-
-
-@ At the end of a row, we append an unset box to the current vlist (for
-\.{\\halign}) or the current hlist (for \.{\\valign}). This unset box
-contains the unset boxes for the columns, separated by the tabskip glue.
-Everything will be set later.
-
-@c
-void fin_row(void)
-{
- pointer p; /* the new unset box */
- if (cur_list.mode_field == -hmode) {
- p = filtered_hpack(cur_list.head_field, cur_list.tail_field, 0,
- additional, fin_row_group, -1, 0, 0);
- pop_nest();
- if (cur_pre_head != cur_pre_tail)
- append_list(cur_pre_head, cur_pre_tail);
- append_to_vlist(p,lua_key_index(alignment));
- if (cur_head != cur_tail)
- append_list(cur_head, cur_tail);
- } else {
- p = filtered_vpackage(vlink(cur_list.head_field),
- 0, additional, max_depth_par, fin_row_group, -1, 0, 0);
- pop_nest();
- vlink(cur_list.tail_field) = p;
- cur_list.tail_field = p;
- space_factor_par = 1000;
- }
- type(p) = unset_node;
- glue_stretch(p) = 0;
- if (every_cr_par != null)
- begin_token_list(every_cr_par, every_cr_text);
- align_peek();
- /* note that |glue_shrink(p)=0| since |glue_shrink==shift_amount| */
-}
-
-
-@ Finally, we will reach the end of the alignment, and we can breathe a
-sigh of relief that memory hasn't overflowed. All the unset boxes will now be
-set so that the columns line up, taking due account of spanned columns.
-
-@c
-void fin_align(void)
-{
- pointer p, q, r, s, u, rr; /* registers for the list operations */
- scaled t, w; /* width of column */
- scaled o; /* shift offset for unset boxes */
- halfword n; /* matching span amount */
- scaled rule_save; /* temporary storage for |overfull_rule| */
- halfword pd; /* temporary storage for |prev_depth| */
- halfword ng; /* temporary storage for |new_glue| */
- if (cur_group != align_group)
- confusion("align1");
- unsave(); /* that |align_group| was for individual entries */
- if (cur_group != align_group)
- confusion("align0");
- unsave(); /* that |align_group| was for the whole alignment */
- if (nest[nest_ptr - 1].mode_field == mmode)
- o = display_indent_par;
- else
- o = 0;
- /* Go through the preamble list, determining the column widths and
- * changing the alignrecords to dummy unset boxes
- */
-
-/* It's time now to dismantle the preamble list and to compute the column
-widths. Let $w_{ij}$ be the maximum of the natural widths of all entries
-that span columns $i$ through $j$, inclusive. The alignrecord for column~$i$
-contains $w_{ii}$ in its |width| field, and there is also a linked list of
-the nonzero $w_{ij}$ for increasing $j$, accessible via the |info| field;
-these span nodes contain the value $j-i+|min_quarterword|$ in their
-|link| fields. The values of $w_{ii}$ were initialized to |null_flag|, which
-we regard as $-\infty$.
-
-The final column widths are defined by the formula
-$$w_j=\max_{1\L i\L j}\biggl( w_{ij}-\sum_{i\L k<j}(t_k+w_k)\biggr),$$
-where $t_k$ is the natural width of the tabskip glue between columns
-$k$ and~$k+1$. However, if $w_{ij}=-\infty$ for all |i| in the range
-|1<=i<=j| (i.e., if every entry that involved column~|j| also involved
-column~|j+1|), we let $w_j=0$, and we zero out the tabskip glue after
-column~|j|.
-
-\TeX\ computes these values by using the following scheme: First $w_1=w_{11}$.
-Then replace $w_{2j}$ by $\max(w_{2j},w_{1j}-t_1-w_1)$, for all $j>1$.
-Then $w_2=w_{22}$. Then replace $w_{3j}$ by $\max(w_{3j},w_{2j}-t_2-w_2)$
-for all $j>2$; and so on. If any $w_j$ turns out to be $-\infty$, its
-value is changed to zero and so is the next tabskip.
-*/
- q = vlink(preamble);
- do {
- flush_list(u_part(q));
- flush_list(v_part(q));
- p = vlink(vlink(q));
- if (width(q) == null_flag) {
- /* Nullify |width(q)| and the tabskip glue following this column */
- width(q) = 0;
- r = vlink(q);
- reset_glue_to_zero(r); /* is a lready copy */
- }
- if (span_ptr(q) != end_span) {
- /* Merge the widths in the span nodes of |q| with those of |p|,
- destroying the span nodes of |q| */
- /*
- Merging of two span-node lists is a typical exercise in the manipulation of
- linearly linked data structures. The essential invariant in the following
- |repeat| loop is that we want to dispense with node |r|, in |q|'s list,
- and |u| is its successor; all nodes of |p|'s list up to and including |s|
- have been processed, and the successor of |s| matches |r| or precedes |r|
- or follows |r|, according as |link(r)=n| or |link(r)>n| or |link(r)<n|.
- */
- t = width(q) + width(vlink(q));
- r = span_ptr(q);
- s = end_span;
- span_ptr(s) = p;
- n = min_quarterword + 1;
- do {
- width(r) = width(r) - t;
- u = span_ptr(r);
- while (span_span(r) > n) {
- s = span_ptr(s);
- n = span_span(span_ptr(s)) + 1;
- }
- if (span_span(r) < n) {
- span_ptr(r) = span_ptr(s);
- span_ptr(s) = r;
- decr(span_span(r));
- s = r;
- } else {
- if (width(r) > width(span_ptr(s)))
- width(span_ptr(s)) = width(r);
- flush_node(r);
- }
- r = u;
- } while (r != end_span);
- }
- type(q) = unset_node;
- span_count(q) = min_quarterword;
- height(q) = 0;
- depth(q) = 0;
- glue_order(q) = normal;
- glue_sign(q) = normal;
- glue_stretch(q) = 0;
- glue_shrink(q) = 0;
- q = p;
- } while (q != null);
-
- /* Package the preamble list, to determine the actual tabskip glue amounts,
- and let |p| point to this prototype box */
- /* Now the preamble list has been converted to a list of alternating unset
- boxes and tabskip glue, where the box widths are equal to the final
- column sizes. In case of \.{\\valign}, we change the widths to heights,
- so that a correct error message will be produced if the alignment is
- overfull or underfull.
- */
-
- decr(save_ptr);
- pack_begin_line = -cur_list.ml_field;
- if (cur_list.mode_field == -vmode) {
- rule_save = overfull_rule_par;
- overfull_rule_par = 0; /* prevent rule from being packaged */
- p = hpack(preamble, saved_value(0), saved_level(0), -1);
- overfull_rule_par = rule_save;
- } else {
- q = vlink(preamble);
- do {
- height(q) = width(q);
- width(q) = 0;
- q = vlink(vlink(q));
- } while (q != null);
- p = filtered_vpackage(preamble,
- saved_value(0), saved_level(0), max_depth_par, preamble_group, -1, 0, 0);
- q = vlink(preamble);
- do {
- width(q) = height(q);
- height(q) = 0;
- q = vlink(vlink(q));
- } while (q != null);
- }
- pack_begin_line = 0;
-
- /* Set the glue in all the unset boxes of the current list */
- q = vlink(cur_list.head_field);
- s = cur_list.head_field;
- while (q != null) {
- if (!is_char_node(q)) {
- if (type(q) == unset_node) {
- /* Set the unset box |q| and the unset boxes in it */
- /* The unset box |q| represents a row that contains one or more unset boxes,
- depending on how soon \.{\\cr} occurred in that row. */
-
- if (cur_list.mode_field == -vmode) {
- type(q) = hlist_node;
- subtype(q) = align_row_list;
- width(q) = width(p);
- } else {
- type(q) = vlist_node;
- subtype(q) = align_row_list;
- height(q) = height(p);
- }
- glue_order(q) = glue_order(p);
- glue_sign(q) = glue_sign(p);
- glue_set(q) = glue_set(p);
- shift_amount(q) = o;
- r = vlink(list_ptr(q));
- assert (type(r) == unset_node);
- s = vlink(list_ptr(p));
- do {
- /* Set the glue in node |r| and change it from an unset node */
- /* A box made from spanned columns will be followed by tabskip glue nodes and
- by empty boxes as if there were no spanning. This permits perfect alignment
- of subsequent entries, and it prevents values that depend on floating point
- arithmetic from entering into the dimensions of any boxes.
- */
- n = span_count(r);
- t = width(s);
- w = t;
- u = hold_head;
- while (n > min_quarterword) {
- decr(n);
- /* Append tabskip glue and an empty box to list |u|,
- and update |s| and |t| as the prototype nodes are passed */
-
- s = vlink(s);
- ng = new_glue(s);
- vlink(u) = ng;
- u = vlink(u);
- subtype(u) = tab_skip_code + 1;
- t = t + width(s);
- if (glue_sign(p) == stretching) {
- if (stretch_order(s) == glue_order(p))
- t = t + round(float_cast(glue_set(p)) * float_cast(stretch(s)));
- } else if (glue_sign(p) == shrinking) {
- if (shrink_order(s) == glue_order(p))
- t = t - round(float_cast(glue_set(p)) * float_cast(shrink(s)));
- }
- s = vlink(s);
- rr = new_null_box();
- vlink(u) = rr;
- u = vlink(u);
- t = t + width(s);
- subtype(u) = align_cell_list;
- if (cur_list.mode_field == -vmode) {
- width(u) = width(s);
- } else {
- type(u) = vlist_node;
- height(u) = width(s);
- }
-
- }
- if (cur_list.mode_field == -vmode) {
- /* Make the unset node |r| into an |hlist_node| of width |w|,
- setting the glue as if the width were |t| */
-
- height(r) = height(q);
- depth(r) = depth(q);
- if (t == width(r)) {
- glue_sign(r) = normal;
- glue_order(r) = normal;
- set_glue_ratio_zero(glue_set(r));
- } else if (t > width(r)) {
- glue_sign(r) = stretching;
- if (glue_stretch(r) == 0)
- set_glue_ratio_zero(glue_set(r));
- else
- glue_set(r) =
- unfloat((double) (t - width(r)) /
- glue_stretch(r));
- } else {
- glue_order(r) = glue_sign(r);
- glue_sign(r) = shrinking;
- if (glue_shrink(r) == 0)
- set_glue_ratio_zero(glue_set(r));
- else if ((glue_order(r) == normal)
- && (width(r) - t > glue_shrink(r)))
- set_glue_ratio_one(glue_set(r));
- else
- glue_set(r) =
- unfloat((double) (width(r) - t) /
- glue_shrink(r));
- }
- width(r) = w;
- type(r) = hlist_node;
- subtype(r) = align_cell_list;
-
- } else {
- /* Make the unset node |r| into a |vlist_node| of height |w|,
- setting the glue as if the height were |t| */
-
- width(r) = width(q);
- if (t == height(r)) {
- glue_sign(r) = normal;
- glue_order(r) = normal;
- set_glue_ratio_zero(glue_set(r));
- } else if (t > height(r)) {
- glue_sign(r) = stretching;
- if (glue_stretch(r) == 0)
- set_glue_ratio_zero(glue_set(r));
- else
- glue_set(r) =
- unfloat((t - height(r)) / glue_stretch(r));
- } else {
- glue_order(r) = glue_sign(r);
- glue_sign(r) = shrinking;
- if (glue_shrink(r) == 0)
- set_glue_ratio_zero(glue_set(r));
- else if ((glue_order(r) == normal)
- && (height(r) - t > glue_shrink(r)))
- set_glue_ratio_one(glue_set(r));
- else
- glue_set(r) =
- unfloat((height(r) - t) / glue_shrink(r));
- }
- height(r) = w;
- type(r) = vlist_node;
- subtype(r) = align_cell_list;
-
- }
- /* subtype(r) = 0; */
- shift_amount(r) = 0;
- if (u != hold_head) { /* append blank boxes to account for spanned nodes */
- vlink(u) = vlink(r);
- vlink(r) = vlink(hold_head);
- r = u;
- }
-
- r = vlink(vlink(r));
- s = vlink(vlink(s));
- } while (r != null);
-
- } else if (type(q) == rule_node) {
- /* Make the running dimensions in rule |q| extend to the
- boundaries of the alignment */
- if (is_running(width(q)))
- width(q) = width(p);
- if (is_running(height(q)))
- height(q) = height(p);
- if (is_running(depth(q)))
- depth(q) = depth(p);
- if (o != 0) {
- r = vlink(q);
- vlink(q) = null;
- q = hpack(q, 0, additional, -1);
- shift_amount(q) = o;
- subtype(q) = align_cell_list;
- vlink(q) = r;
- vlink(s) = q;
- }
- }
- }
- s = q;
- q = vlink(q);
- }
- flush_node_list(p);
- pop_alignment();
- /* Insert the current list into its environment */
- /* We now have a completed alignment, in the list that starts at |cur_list.head_field|
- and ends at |cur_list.tail_field|. This list will be merged with the one that encloses
- it. (In case the enclosing mode is |mmode|, for displayed formulas,
- we will need to insert glue before and after the display; that part of the
- program will be deferred until we're more familiar with such operations.)
- */
- pd = prev_depth_par;
- p = vlink(cur_list.head_field);
- q = cur_list.tail_field;
- pop_nest();
- if (cur_list.mode_field == mmode) {
- finish_display_alignment(p, q, pd);
- } else {
- prev_depth_par = pd; /* aux:=aux_save; */
- vlink(cur_list.tail_field) = p;
- if (p != null)
- cur_list.tail_field = q;
- if (cur_list.mode_field == vmode) {
- if (!output_active)
- lua_node_filter_s(buildpage_filter_callback,lua_key_index(alignment));
- build_page();
- }
- }
-}
-
-@ The token list |omit_template| just referred to is a constant token
-list that contains the special control sequence \.{\\endtemplate} only.
-
-@c
-void initialize_alignments(void)
-{
- token_info(omit_template) = end_template_token; /* |link(omit_template)=null| */
- span_span(end_span) = max_quarterword + 1;
- span_ptr(end_span) = null;
-}