% $Id$
% tex.ch for C compilation with web2c, derived from various other change files.
% By Tim Morgan, UC Irvine ICS Department, and many others.
%
% Be very careful when making changes to this file, as it is used to
% generate TeX, e-TeX, and pdfTeX, and most changes require similar
% changes to be made to the Aleph sources.
%
% (05/28/86) ETM Started with TeX 2.0
% (06/03/87) ETM Brought up to TeX 2.2
% (09/26/87) ETM Brought up to TeX 2.3
% (10/01/87) ETM Brought up to TeX 2.5
% (12/21/87) ETM Brought up to TeX 2.7
% (01/14/88) ETM Brought up to TeX 2.9
% (02/20/88) PAM Revised format and module numbers
% (03/01/88) ETM Eliminated some unused variables and unnecessary tests
% (05/09/88) ETM Added yet another casting bug fix
% (06/21/88) ETM Brought up to TeX version 2.93
% (12/11/88) ETM Brought up to TeX version 2.94
% (01/12/89) PAM Brought up to TeX version 2.95
% (02/14/89) ETM Brought up to TeX version 2.96
% (03/10/89) ETM Brought up to TeX version 2.98
% (07/06/89) ETM Brought up to TeX version 2.991
% (11/30/89) KB  To version 2.992 (8-bit).
% (01/10/90) SR  To version 2.993.
% (03/27/90) KY  To version 3.0.
% (more recent changes in ChangeLog)
%
% The TeX program is copyright (C) 1982 by D. E. Knuth.
% TeX is a trademark of the American Mathematical Society.
%
% Includes MLTEX.CH (Version 2.2) in text format, as of Dec 17, 1995.
% MLTeX is copyright (C) 1990-92 by Michael J. Ferguson; all rights reserved.
% MLTeX Version 2.2 is copyright (C) 1995 by B. Raichle; all rights reserved.
%
% The MLTeX changes are copyrighted so that we have some chance to
% forbid unauthorized copies; we explicitly authorize copying of
% correct MLTeX implementations, and not of incorrect ones!
%
% (This means that you can use the MLTeX changes as free as you can
% use TeX and its algorithm.)
%
% Copying of this file is authorized only if either
% (1) you make absolutely no changes to your copy, including name, or
% (2) if you do make changes, you name it to something other than
%     "mltex.ch", "char_sub.ch", or "charsub.ch".
%
% Except for MLTeX, the new code in this file is in the public domain.
%
% The part, module, and line numbers in this change file refer to
% TEX.WEB 3.141592653 as of January, 2021 (published as Donald E. Knuth,
% TeX: The Program, Volume B of Computers & Typesetting Jubilee Editions).

@x [0.0] l.88 - WEAVE: print changes only.
  \def\?##1]{\hbox to 1in{\hfil##1.\ }}
  }
@y
  \def\?##1]{\hbox{Changes to ##1.\ }}
  }
\let\maybe=\iffalse
@z

@x [1.2] l.191 - MLTeX: add comment about banner line change
November 1984].
@y
November 1984].

ML\TeX{} will add new primitives changing the behaviour of \TeX.  The
|banner| string has to be changed.  We do not change the |banner|
string, but will output an additional line to make clear that this is
a modified \TeX{} version.

@z

@x [1.2] l.193
@d banner=='This is TeX, Version 3.141592653' {printed when \TeX\ starts}
@y
@d TeX_banner_k=='This is TeXk, Version 3.141592653' {printed when \TeX\ starts}
@d TeX_banner=='This is TeX, Version 3.141592653' {printed when \TeX\ starts}
@#
@d banner==TeX_banner
@d banner_k==TeX_banner_k
@z

@x [1.4] l.244 - program header
Actually the heading shown here is not quite normal: The |program| line
does not mention any |output| file, because \ph\ would ask the \TeX\ user
to specify a file name if |output| were specified here.
@:PASCAL H}{\ph@>
@^system dependencies@>
@y
@z

@x [1.4] l.255 - labels in outer block not needed
program TEX; {all file names are defined dynamically}
label @<Labels in the outer block@>@/
@y
program TEX; {all file names are defined dynamically}
@z

@x [1.6] l.279 - labels in outer block not needed
@ Three labels must be declared in the main program, so we give them
symbolic names.

@d start_of_TEX=1 {go here when \TeX's variables are initialized}
@d end_of_TEX=9998 {go here to close files and terminate gracefully}
@d final_end=9999 {this label marks the ending of the program}

@<Labels in the out...@>=
start_of_TEX@t\hskip-2pt@>, end_of_TEX@t\hskip-2pt@>,@,final_end;
  {key control points}
@y
@ For Web2c, labels are not declared in the main program, but
we still have to declare the symbolic names.

@d start_of_TEX=1 {go here when \TeX's variables are initialized}
@d final_end=9999 {this label marks the ending of the program}
@z

% Here we change these WEB symbols, which are used much as #ifdef's
% are in C, into something which will get translated into actual #ifdef's.
@x [1.7] l.304 - debug..gubed, stat..tats
@d debug==@{ {change this to `$\\{debug}\equiv\null$' when debugging}
@d gubed==@t@>@} {change this to `$\\{gubed}\equiv\null$' when debugging}
@y
@d debug==ifdef('TEXMF_DEBUG')
@d gubed==endif('TEXMF_DEBUG')
@z
@x [1.7] l.309 - debug..gubed, stat..tats
@d stat==@{ {change this to `$\\{stat}\equiv\null$' when gathering
  usage statistics}
@d tats==@t@>@} {change this to `$\\{tats}\equiv\null$' when gathering
  usage statistics}
@y
@d stat==ifdef('STAT')
@d tats==endif('STAT')
@z

@x [1.8] l.322 - Somewhat different for `init...tini'..  310 m.8
the codewords `$|init|\ldots|tini|$'.

@d init== {change this to `$\\{init}\equiv\.{@@\{}$' in the production version}
@d tini== {change this to `$\\{tini}\equiv\.{@@\}}$' in the production version}
@y
the codewords `$|init|\ldots|tini|$' for declarations and by the codewords
`$|Init|\ldots|Tini|$' for executable code.  This distinction is helpful for
implementations where a run-time switch differentiates between the two
versions of the program.

@d init==ifdef('INITEX')
@d tini==endif('INITEX')
@d Init==init if ini_version then begin
@d Tini==end;@+tini
@f Init==begin
@f Tini==end
@z

@x [1.8] l.331 - init...tini is dynamic
@!init @<Initialize table entries (done by \.{INITEX} only)@>@;@+tini
@y
@!Init @<Initialize table entries (done by \.{INITEX} only)@>@;@+Tini
@z

@x [1.11] l.389 - Compile-time constants: most removed for dynamic allocation.
@<Constants...@>=
@!mem_max=30000; {greatest index in \TeX's internal |mem| array;
  must be strictly less than |max_halfword|;
  must be equal to |mem_top| in \.{INITEX}, otherwise |>=mem_top|}
@!mem_min=0; {smallest index in \TeX's internal |mem| array;
  must be |min_halfword| or more;
  must be equal to |mem_bot| in \.{INITEX}, otherwise |<=mem_bot|}
@!buf_size=500; {maximum number of characters simultaneously present in
  current lines of open files and in control sequences between
  \.{\\csname} and \.{\\endcsname}; must not exceed |max_halfword|}
@!error_line=72; {width of context lines on terminal error messages}
@!half_error_line=42; {width of first lines of contexts in terminal
  error messages; should be between 30 and |error_line-15|}
@!max_print_line=79; {width of longest text lines output; should be at least 60}
@!stack_size=200; {maximum number of simultaneous input sources}
@!max_in_open=6; {maximum number of input files and error insertions that
  can be going on simultaneously}
@!font_max=75; {maximum internal font number; must not exceed |max_quarterword|
  and must be at most |font_base+256|}
@!font_mem_size=20000; {number of words of |font_info| for all fonts}
@!param_size=60; {maximum number of simultaneous macro parameters}
@!nest_size=40; {maximum number of semantic levels simultaneously active}
@!max_strings=3000; {maximum number of strings; must not exceed |max_halfword|}
@!string_vacancies=8000; {the minimum number of characters that should be
  available for the user's control sequences and font names,
  after \TeX's own error messages are stored}
@!pool_size=32000; {maximum number of characters in strings, including all
  error messages and help texts, and the names of all fonts and
  control sequences; must exceed |string_vacancies| by the total
  length of \TeX's own strings, which is currently about 23000}
@!save_size=600; {space for saving values outside of current group; must be
  at most |max_halfword|}
@!trie_size=8000; {space for hyphenation patterns; should be larger for
  \.{INITEX} than it is in production versions of \TeX}
@!trie_op_size=500; {space for ``opcodes'' in the hyphenation patterns}
@!dvi_buf_size=800; {size of the output buffer; must be a multiple of 8}
@!file_name_size=40; {file names shouldn't be longer than this}
@!pool_name='TeXformats:TEX.POOL                     ';
  {string of length |file_name_size|; tells where the string pool appears}
@y
@d file_name_size == maxint
@d ssup_error_line = 255
@d ssup_max_strings == 2097151
{Larger values than 65536 cause the arrays to consume much more memory.}
@d ssup_trie_opcode == 65535
@d ssup_trie_size == @"3FFFFF

@d ssup_hyph_size == 65535 {Changing this requires changing (un)dumping!}
@d iinf_hyphen_size == 610 {Must be not less than |hyph_prime|!}

@d max_font_max=9000 {maximum number of internal fonts; this can be
                      increased, but |hash_size+max_font_max|
                      should not exceed 29000.}
@d font_base=0 {smallest internal font number; must be
                |>= min_quarterword|; do not change this without
                modifying the dynamic definition of the font arrays.}


@<Constants...@>=
@!hash_offset=514; {smallest index in hash array, i.e., |hash_base| }
  {Use |hash_offset=0| for compilers which cannot decrement pointers.}
@!trie_op_size=35111; {space for ``opcodes'' in the hyphenation patterns;
  best if relatively prime to 313, 361, and 1009.}
@!neg_trie_op_size=-35111; {for lower |trie_op_hash| array bound;
  must be equal to |-trie_op_size|.}
@!min_trie_op=0; {first possible trie op code for any language}
@!max_trie_op=ssup_trie_opcode; {largest possible trie opcode for any language}
@!pool_name=TEXMF_POOL_NAME; {this is configurable, for the sake of ML-\TeX}
  {string of length |file_name_size|; tells where the string pool appears}
@!engine_name=TEXMF_ENGINE_NAME; {the name of this engine}
@#
@!inf_mem_bot = 0;
@!sup_mem_bot = 1;

@!inf_main_memory = 3000;
@!sup_main_memory = 256000000;

@!inf_trie_size = 8000;
@!sup_trie_size = ssup_trie_size;

@!inf_max_strings = 3000;
@!sup_max_strings = ssup_max_strings;
@!inf_strings_free = 100;
@!sup_strings_free = sup_max_strings;

@!inf_buf_size = 500;
@!sup_buf_size = 30000000;

@!inf_nest_size = 40;
@!sup_nest_size = 4000;

@!inf_max_in_open = 6;
@!sup_max_in_open = 127;

@!inf_param_size = 60;
@!sup_param_size = 32767;

@!inf_save_size = 600;
@!sup_save_size = 30000000;

@!inf_stack_size = 200;
@!sup_stack_size = 30000;

@!inf_dvi_buf_size = 800;
@!sup_dvi_buf_size = 65536;

@!inf_font_mem_size = 20000;
@!sup_font_mem_size = 147483647; {|integer|-limited, so 2 could be prepended?}

@!sup_font_max = max_font_max;
@!inf_font_max = 50; {could be smaller, but why?}

@!inf_pool_size = 32000;
@!sup_pool_size = 40000000;
@!inf_pool_free = 1000;
@!sup_pool_free = sup_pool_size;
@!inf_string_vacancies = 8000;
@!sup_string_vacancies = sup_pool_size - 23000;

@!sup_hash_extra = sup_max_strings;
@!inf_hash_extra = 0;

@!sup_hyph_size = ssup_hyph_size;
@!inf_hyph_size = iinf_hyphen_size; {Must be not less than |hyph_prime|!}

@!inf_expand_depth = 10;
@!sup_expand_depth = 10000000;
@z

@x [1.12] l.441 - Constants that are WEB numeric macros.
@d mem_bot=0 {smallest index in the |mem| array dumped by \.{INITEX};
  must not be less than |mem_min|}
@d mem_top==30000 {largest index in the |mem| array dumped by \.{INITEX};
  must be substantially larger than |mem_bot|
  and not greater than |mem_max|}
@d font_base=0 {smallest internal font number; must not be less
  than |min_quarterword|}
@d hash_size=2100 {maximum number of control sequences; it should be at most
  about |(mem_max-mem_min)/10|}
@d hash_prime=1777 {a prime number equal to about 85\pct! of |hash_size|}
@d hyph_size=307 {another prime; the number of \.{\\hyphenation} exceptions}
@y
@d hash_size=15000 {maximum number of control sequences; it should be at most
  about |(mem_max-mem_min)/10|; see also |font_max|}
@d hash_prime=8501 {a prime number equal to about 85\pct! of |hash_size|}
@d hyph_prime=607 {another prime for hashing \.{\\hyphenation} exceptions;
                if you change this, you should also change |iinf_hyphen_size|.}
@z

@x [1.16] l.512 - Use C macros for `incr' and `decr'.
@d incr(#) == #:=#+1 {increase a variable by unity}
@d decr(#) == #:=#-1 {decrease a variable by unity}
@y
@z

% The text_char type is used as an array index into xord.  The
% default type `char' produces signed integers, which are bad array
% indices in C.
@x [2.19] l.579 - data type text_char is 8-bit ASCII_code
@d text_char == char {the data type of characters in text files}
@y
@d text_char == ASCII_code {the data type of characters in text files}
@z

@x [2.20] l.593 - printable characters
@!xchr: array [ASCII_code] of text_char;
  {specifies conversion of output characters}
@y
xchr: array [ASCII_code] of text_char;
   { specifies conversion of output characters }
xprn: array [ASCII_code] of ASCII_code;
   { non zero iff character is printable }
@z

@x [2.23] l.737 - Translate characters if desired, otherwise allow them all.
for i:=0 to @'37 do xchr[i]:=' ';
for i:=@'177 to @'377 do xchr[i]:=' ';
@y
{Initialize |xchr| to the identity mapping.}
for i:=0 to @'37 do xchr[i]:=i;
for i:=@'177 to @'377 do xchr[i]:=i;
@z

@x [2.24] l.749 - Don't reinitialize xord.
for i:=0 to @'176 do xord[xchr[i]]:=i;
@y
for i:=0 to @'176 do xord[xchr[i]]:=i;
{Set |xprn| for printable ASCII, unless |eight_bit_p| is set.}
for i:=0 to 255 do xprn[i]:=(eight_bit_p or ((i>=" ")and(i<="~")));

{The idea for this dynamic translation comes from the patch by
 Libor Skarvada \.{<libor@@informatics.muni.cz>}
 and Petr Sojka \.{<sojka@@informatics.muni.cz>}. I didn't use any of the
 actual code, though, preferring a more general approach.}

{This updates the |xchr|, |xord|, and |xprn| arrays from the provided
 |translate_filename|.  See the function definition in \.{texmfmp.c} for
 more comments.}
if translate_filename then read_tcx_file;
@z

% [3.26] name_of_file is no longer an array.  And change the destination
% type to text_char, which fixes:
%
% Date: 19 Sep 1994 10:38:24 +0200
% From: thorinn@diku.dk (Lars Mathiesen)
%       When echoed to the screen and in the log, character codes
%       above '177 in file names are shown wrongly (typically as ^@).
%
@x [3.26] l.803 - name_of_file is no longer an array
@!name_of_file:packed array[1..file_name_size] of char;@;@/
  {on some systems this may be a \&{record} variable}
@y
@!name_of_file:^text_char;
@z

@x [3.27] l.808 - Do file opening in C.
@ The \ph\ compiler with which the present version of \TeX\ was prepared has
extended the rules of \PASCAL\ in a very convenient way. To open file~|f|,
we can write
$$\vbox{\halign{#\hfil\qquad&#\hfil\cr
|reset(f,@t\\{name}@>,'/O')|&for input;\cr
|rewrite(f,@t\\{name}@>,'/O')|&for output.\cr}}$$
The `\\{name}' parameter, which is of type `{\bf packed array
$[\langle\\{any}\rangle]$ of \\{char}}', stands for the name of
the external file that is being opened for input or output.
Blank spaces that might appear in \\{name} are ignored.

The `\.{/O}' parameter tells the operating system not to issue its own
error messages if something goes wrong. If a file of the specified name
cannot be found, or if such a file cannot be opened for some other reason
(e.g., someone may already be trying to write the same file), we will have
|@!erstat(f)<>0| after an unsuccessful |reset| or |rewrite|.  This allows
\TeX\ to undertake appropriate corrective action.
@:PASCAL H}{\ph@>
@^system dependencies@>

\TeX's file-opening procedures return |false| if no file identified by
|name_of_file| could be opened.

@d reset_OK(#)==erstat(#)=0
@d rewrite_OK(#)==erstat(#)=0

@p function a_open_in(var f:alpha_file):boolean;
  {open a text file for input}
begin reset(f,name_of_file,'/O'); a_open_in:=reset_OK(f);
end;
@#
function a_open_out(var f:alpha_file):boolean;
  {open a text file for output}
begin rewrite(f,name_of_file,'/O'); a_open_out:=rewrite_OK(f);
end;
@#
function b_open_in(var f:byte_file):boolean;
  {open a binary file for input}
begin reset(f,name_of_file,'/O'); b_open_in:=reset_OK(f);
end;
@#
function b_open_out(var f:byte_file):boolean;
  {open a binary file for output}
begin rewrite(f,name_of_file,'/O'); b_open_out:=rewrite_OK(f);
end;
@#
function w_open_in(var f:word_file):boolean;
  {open a word file for input}
begin reset(f,name_of_file,'/O'); w_open_in:=reset_OK(f);
end;
@#
function w_open_out(var f:word_file):boolean;
  {open a word file for output}
begin rewrite(f,name_of_file,'/O'); w_open_out:=rewrite_OK(f);
end;
@y
@ All of the file opening functions are defined in C.
@z

@x [3.28] l.864 - Do file closing in C.
@ Files can be closed with the \ph\ routine `|close(f)|', which
@:PASCAL H}{\ph@>
@^system dependencies@>
should be used when all input or output with respect to |f| has been completed.
This makes |f| available to be opened again, if desired; and if |f| was used for
output, the |close| operation makes the corresponding external file appear
on the user's area, ready to be read.

These procedures should not generate error messages if a file is
being closed before it has been successfully opened.

@p procedure a_close(var f:alpha_file); {close a text file}
begin close(f);
end;
@#
procedure b_close(var f:byte_file); {close a binary file}
begin close(f);
end;
@#
procedure w_close(var f:word_file); {close a word file}
begin close(f);
end;
@y
@ And all the file closing routines as well.
@z

@x [3.30] l.903 - Array size of input buffer is determined at runtime.
@!buffer:array[0..buf_size] of ASCII_code; {lines of characters being read}
@y
@!buffer:^ASCII_code; {lines of characters being read}
@z

@x [3.31] l.948 - Do `input_ln' in C.
@p function input_ln(var f:alpha_file;@!bypass_eoln:boolean):boolean;
  {inputs the next line or returns |false|}
var last_nonblank:0..buf_size; {|last| with trailing blanks removed}
begin if bypass_eoln then if not eof(f) then get(f);
  {input the first character of the line into |f^|}
last:=first; {cf.\ Matthew 19\thinspace:\thinspace30}
if eof(f) then input_ln:=false
else  begin last_nonblank:=first;
  while not eoln(f) do
    begin if last>=max_buf_stack then
      begin max_buf_stack:=last+1;
      if max_buf_stack=buf_size then
        @<Report overflow of the input buffer, and abort@>;
      end;
    buffer[last]:=xord[f^]; get(f); incr(last);
    if buffer[last-1]<>" " then last_nonblank:=last;
    end;
  last:=last_nonblank; input_ln:=true;
  end;
end;
@y
We define |input_ln| in C, for efficiency. Nevertheless we quote the module
`Report overflow of the input buffer, and abort' here in order to make
\.{WEAVE} happy, since part of that module is needed by e-TeX.

@p @{ @<Report overflow of the input buffer, and abort@> @}
@z

% [3.32] `term_in' and `term_out' are standard input and output.
% Declare the variables that used to be constants.
@x [3.32] l.975 - `term_in' and `term_out' are standard input and output.
@<Glob...@>=
@!term_in:alpha_file; {the terminal as an input file}
@!term_out:alpha_file; {the terminal as an output file}
@y
@d term_in==stdin {the terminal as an input file}
@d term_out==stdout {the terminal as an output file}

@<Glob...@>=
@!init
@!ini_version:boolean; {are we \.{INITEX}?}
@!dump_option:boolean; {was the dump name option used?}
@!dump_line:boolean; {was a \.{\%\AM format} line seen?}
tini@/
@#
@!dump_name:const_cstring; {format name for terminal display}
@#
@!bound_default:integer; {temporary for setup}
@!bound_name:const_cstring; {temporary for setup}
@#
@!mem_bot:integer;{smallest index in the |mem| array dumped by \.{INITEX};
  must not be less than |mem_min|}
@!main_memory:integer; {total memory words allocated in initex}
@!extra_mem_bot:integer; {|mem_min:=mem_bot-extra_mem_bot| except in \.{INITEX}}
@!mem_min:integer; {smallest index in \TeX's internal |mem| array;
  must be |min_halfword| or more;
  must be equal to |mem_bot| in \.{INITEX}, otherwise |<=mem_bot|}
@!mem_top:integer; {largest index in the |mem| array dumped by \.{INITEX};
  must be substantially larger than |mem_bot|,
  equal to |mem_max| in \.{INITEX}, else not greater than |mem_max|}
@!extra_mem_top:integer; {|mem_max:=mem_top+extra_mem_top| except in \.{INITEX}}
@!mem_max:integer; {greatest index in \TeX's internal |mem| array;
  must be strictly less than |max_halfword|;
  must be equal to |mem_top| in \.{INITEX}, otherwise |>=mem_top|}
@!error_line:integer; {width of context lines on terminal error messages}
@!half_error_line:integer; {width of first lines of contexts in terminal
  error messages; should be between 30 and |error_line-15|}
@!max_print_line:integer;
  {width of longest text lines output; should be at least 60}
@!max_strings:integer; {maximum number of strings; must not exceed |max_halfword|}
@!strings_free:integer; {strings available after format loaded}
@!string_vacancies:integer; {the minimum number of characters that should be
  available for the user's control sequences and font names,
  after \TeX's own error messages are stored}
@!pool_size:integer; {maximum number of characters in strings, including all
  error messages and help texts, and the names of all fonts and
  control sequences; must exceed |string_vacancies| by the total
  length of \TeX's own strings, which is currently about 23000}
@!pool_free:integer;{pool space free after format loaded}
@!font_mem_size:integer; {number of words of |font_info| for all fonts}
@!font_max:integer; {maximum internal font number; ok to exceed |max_quarterword|
  and must be at most |font_base|+|max_font_max|}
@!font_k:integer; {loop variable for initialization}
@!hyph_size:integer; {maximum number of hyphen exceptions}
@!trie_size:integer; {space for hyphenation patterns; should be larger for
  \.{INITEX} than it is in production versions of \TeX.  50000 is
  needed for English, German, and Portuguese.}
@!buf_size:integer; {maximum number of characters simultaneously present in
  current lines of open files and in control sequences between
  \.{\\csname} and \.{\\endcsname}; must not exceed |max_halfword|}
@!stack_size:integer; {maximum number of simultaneous input sources}
@!max_in_open:integer; {maximum number of input files and error insertions that
  can be going on simultaneously}
@!param_size:integer; {maximum number of simultaneous macro parameters}
@!nest_size:integer; {maximum number of semantic levels simultaneously active}
@!save_size:integer; {space for saving values outside of current group; must be
  at most |max_halfword|}
@!dvi_buf_size:integer; {size of the output buffer; must be a multiple of 8}
@!expand_depth:integer; {limits recursive calls to the |expand| procedure}
@!parse_first_line_p:cinttype; {parse the first line for options}
@!file_line_error_style_p:cinttype; {format messages as file:line:error}
@!eight_bit_p:cinttype; {make all characters printable by default}
@!halt_on_error_p:cinttype; {stop at first error}
@!halting_on_error_p:boolean; {already trying to halt?}
@!quoted_filename:boolean; {current filename is quoted}
{Variables for source specials}
@!src_specials_p : boolean;{Whether |src_specials| are enabled at all}
@!insert_src_special_auto : boolean;
@!insert_src_special_every_par : boolean;
@!insert_src_special_every_parend : boolean;
@!insert_src_special_every_cr : boolean;
@!insert_src_special_every_math : boolean;
@!insert_src_special_every_hbox : boolean;
@!insert_src_special_every_vbox : boolean;
@!insert_src_special_every_display : boolean;
@z

@x [3.33] l.979 - We don't need to open terminal files.
@ Here is how to open the terminal files
in \ph. The `\.{/I}' switch suppresses the first |get|.
@:PASCAL H}{\ph@>
@^system dependencies@>

@d t_open_in==reset(term_in,'TTY:','/O/I') {open the terminal for text input}
@d t_open_out==rewrite(term_out,'TTY:','/O') {open the terminal for text output}
@y
@ Here is how to open the terminal files.  |t_open_out| does nothing.
|t_open_in|, on the other hand, does the work of ``rescanning,'' or getting
any command line arguments the user has provided.  It's defined in C.

@d t_open_out == {output already open for text output}
@z

@x [3.34] l.998 - Flushing output to terminal files.
these operations can be specified in \ph:
@:PASCAL H}{\ph@>
@^system dependencies@>

@d update_terminal == break(term_out) {empty the terminal output buffer}
@d clear_terminal == break_in(term_in,true) {clear the terminal input buffer}
@y
these operations can be specified with {\mc UNIX}.  |update_terminal|
does an |fflush|. |clear_terminal| is redefined
to do nothing, since the user should control the terminal.
@^system dependencies@>

@d update_terminal == fflush (term_out)
@d clear_terminal == do_nothing
@z

@x [3.35] l.1034 - needed for e-TeX, but differently
@<Report overflow of the input buffer, and abort@>=
if format_ident=0 then
  begin write_ln(term_out,'Buffer size exceeded!'); goto final_end;
@.Buffer size exceeded@>
  end
else begin cur_input.loc_field:=first; cur_input.limit_field:=last-1;
@y
Routine is implemented in C; part of module is, however, needed for e-TeX.

@<Report overflow of the input buffer, and abort@>=
  begin cur_input.loc_field:=first; cur_input.limit_field:=last-1;
@z

@x [3.37] l.1072 - |init_terminal|, reading the command line.
@ The following program does the required initialization
without retrieving a possible command line.
It should be clear how to modify this routine to deal with command lines,
if the system permits them.
@^system dependencies@>

@p function init_terminal:boolean; {gets the terminal input started}
label exit;
begin t_open_in;
@y
@ The following program does the required initialization.
Iff anything has been specified on the command line, then |t_open_in|
will return with |last > first|.
@^system dependencies@>

@p function init_terminal:boolean; {gets the terminal input started}
label exit;
begin t_open_in;
if last > first then
  begin loc := first;
  while (loc < last) and (buffer[loc]=' ') do incr(loc);
  if loc < last then
    begin init_terminal := true; goto exit;
    end;
  end;
@z

@x [3.37] l.1085 - |init_terminal|, output missing newline.
    write(term_out,'! End of file on the terminal... why?');
@y
    write_ln(term_out,'! End of file on the terminal... why?');
@z

@x [4.38] l.1144 - Array size for string pool is determined at runtime.
@!pool_pointer = 0..pool_size; {for variables that point into |str_pool|}
@!str_number = 0..max_strings; {for variables that point into |str_start|}
@y
@!pool_pointer = integer; {for variables that point into |str_pool|}
@!str_number = 0..ssup_max_strings; {for variables that point into |str_start|}
@z

@x [4.39] l.1149 - Dynamically size pool arrays.
@!str_pool:packed array[pool_pointer] of packed_ASCII_code; {the characters}
@!str_start : array[str_number] of pool_pointer; {the starting pointers}
@y
@!str_pool: ^packed_ASCII_code; {the characters}
@!str_start : ^pool_pointer; {the starting pointers}
@z

@x [4.47] l.1255 - string recycling
@p @!init function get_strings_started:boolean; {initializes the string pool,
@y
@p @t\4@>@<Declare additional routines for string recycling@>@/

@!init function get_strings_started:boolean; {initializes the string pool,
@z

@x [4.49] l.1290 - Change documentation (probably needed in more places)
would like string @'32 to be the single character @'32 instead of the
@y
would like string @'32 to be printed as the single character @'32
instead of the
@z

% [4.51] Open the pool file using a path, and can't do string
% assignments directly.  (`strcpy' and `strlen' work here because
% `pool_name' is a constant string, and thus ends in a null and doesn't
% start with a space.)
@x [4.51] l.1332 - Open the pool file.
name_of_file:=pool_name; {we needn't set |name_length|}
if a_open_in(pool_file) then
@y
name_length := strlen (pool_name);
name_of_file := xmalloc_array (ASCII_code, name_length + 1);
strcpy (stringcast(name_of_file+1), pool_name); {copy the string}
if a_open_in (pool_file, kpse_texpool_format) then
@z

@x [4.51] l.1340 - Make `TEX.POOL' lowercase, and change how it's read.
else  bad_pool('! I can''t read TEX.POOL.')
@y
else  bad_pool('! I can''t read ', pool_name, '; bad path?')
@z
@x [4.52] l.1344 - Make `TEX.POOL' lowercase, and change how it's read.
begin if eof(pool_file) then bad_pool('! TEX.POOL has no check sum.');
@.TEX.POOL has no check sum@>
read(pool_file,m,n); {read two digits of string length}
@y
begin if eof(pool_file) then bad_pool('! ', pool_name, ' has no check sum.');
@.TEX.POOL has no check sum@>
read(pool_file,m); read(pool_file,n); {read two digits of string length}
@z
@x [4.52] l.1350 - Make `TEX.POOL' lowercase, and change how it's read.
    bad_pool('! TEX.POOL line doesn''t begin with two digits.');
@y
    bad_pool('! ', pool_name, ' line doesn''t begin with two digits.');
@z
@x [4.53] l.1372 - Make `TEX.POOL' lowercase, and change how it's read.
  bad_pool('! TEX.POOL check sum doesn''t have nine digits.');
@y
  bad_pool('! ', pool_name, ' check sum doesn''t have nine digits.');
@z
@x [4.53] l.1378 - Make `TEX.POOL' lowercase, and change how it's read.
done: if a<>@$ then bad_pool('! TEX.POOL doesn''t match; TANGLE me again.');
@y
done: if a<>@$ then
  bad_pool('! ', pool_name, ' doesn''t match; tangle me again (or fix the path).');
@z

@x [5.54] l.1440 - error_line
@!trick_buf:array[0..error_line] of ASCII_code; {circular buffer for
@y
@!trick_buf:array[0..ssup_error_line] of ASCII_code; {circular buffer for
@z

@x [5.61] l.1574 - If the ``src-specials'' feature is active, change the banner.
wterm(banner);
@y
if src_specials_p or file_line_error_style_p or parse_first_line_p then
  wterm(banner_k)
else
  wterm(banner);
@z

@x [5.61] l.1575 - Print rest of banner.
if format_ident=0 then wterm_ln(' (no format preloaded)')
else  begin slow_print(format_ident); print_ln;
  end;
@y
wterm(version_string);
if format_ident=0 then wterm_ln(' (preloaded format=',dump_name,')')
else  begin slow_print(format_ident); print_ln;
  end;
if shellenabledp then begin
  wterm(' ');
  if restrictedshell then begin
    wterm('restricted ');
  end;
  wterm_ln('\write18 enabled.');
end;
if src_specials_p then begin
  wterm_ln(' Source specials enabled.')
end;
if translate_filename then begin
  wterm(' (');
  fputs(translate_filename, stdout);
  wterm_ln(')');
end;
@z

@x [5.71] l.1713 - term_input: set limit when fatal_error
if not input_ln(term_in,true) then fatal_error("End of file on the terminal!");
@y
if not input_ln(term_in,true) then begin
  limit:=0; fatal_error("End of file on the terminal!"); end;
@z

@x [6.73] l.1750 - Add unspecified_mode.
@d error_stop_mode=3 {stops at every opportunity to interact}
@y
@d error_stop_mode=3 {stops at every opportunity to interact}
@d unspecified_mode=4 {extra value for command-line switch}
@z

@x [6.73] l.1752 - file:line:error style error messages.
  print_nl("! "); print(#);
@y
  if file_line_error_style_p then print_file_line
  else print_nl("! ");
  print(#);
@z


@x [6.73] l.1756 - Add interaction_option.
@!interaction:batch_mode..error_stop_mode; {current level of interaction}
@y
@!interaction:batch_mode..error_stop_mode; {current level of interaction}
@!interaction_option:batch_mode..unspecified_mode; {set from command line}
@z

@x [6.74] l.1758 - Allow override by command line switch.
@ @<Set init...@>=interaction:=error_stop_mode;
@y
@ @<Set init...@>=if interaction_option=unspecified_mode then
  interaction:=error_stop_mode
else
  interaction:=interaction_option;
@z

% [6.81] Eliminate nonlocal goto, since C doesn't have them.
% Plus, it's nicer just to do an exit with the appropriate status code
% under Unix.  We call it `uexit' because there's a WEB symbol called
% `exit' already.  We use a C macro to change `uexit' back to `exit'.
@x [6.81] l.1860 - Eliminate nonlocal goto, since C doesn't have them.
@ The |jump_out| procedure just cuts across all active procedure levels and
goes to |end_of_TEX|. This is the only nontrivial |@!goto| statement in the
whole program. It is used when there is no recovery from a particular error.

Some \PASCAL\ compilers do not implement non-local |goto| statements.
@^system dependencies@>
In such cases the body of |jump_out| should simply be
`|close_files_and_terminate|;\thinspace' followed by a call on some system
procedure that quietly terminates the program.

@<Error hand...@>=
procedure jump_out;
begin goto end_of_TEX;
end;
@y
@ The |jump_out| procedure just cuts across all active procedure levels.
The body of |jump_out| simply calls
`|close_files_and_terminate|;\thinspace' followed by a call on some system
procedure that quietly terminates the program.
@^system dependencies@>

@f noreturn==procedure

@d do_final_end==begin
   update_terminal;
   ready_already:=0;
   if (history <> spotless) and (history <> warning_issued) then
       uexit(1)
   else
       uexit(0);
   end

@<Error hand...@>=
noreturn procedure jump_out;
begin
close_files_and_terminate;
do_final_end;
end;
@z

@x [6.82] l.1884 - halt on error?
print_char("."); show_context;
@y
print_char("."); show_context;
if (halt_on_error_p) then begin
  {If |close_files_and_terminate| generates an error, we'll end up back
   here; just give up in that case. If files are truncated, too bad.}
  if (halting_on_error_p) then do_final_end; {quit immediately}
  halting_on_error_p:=true;
  history:=fatal_error_stop;
  jump_out;
end;
@z

@x [6.84] l.1908 - Implement the switch-to-editor option.
line ready to be edited. But such an extension requires some system
wizardry, so the present implementation simply types out the name of the
file that should be
edited and the relevant line number.
@^system dependencies@>

There is a secret `\.D' option available when the debugging routines haven't
been commented~out.
@^debugging@>
@y
line ready to be edited.
We do this by calling the external procedure |call_edit| with a pointer to
the filename, its length, and the line number.
However, here we just set up the variables that will be used as arguments,
since we don't want to do the switch-to-editor until after TeX has closed
its files.
@^system dependencies@>

There is a secret `\.D' option available when the debugging routines haven't
been commented~out.
@^debugging@>
@d edit_file==input_stack[base_ptr]
@z

@x [6.84] l.1923 - Implement the switch-to-editor option.
"E": if base_ptr>0 then if input_stack[base_ptr].name_field>=256 then
  begin print_nl("You want to edit file ");
@.You want to edit file x@>
  slow_print(input_stack[base_ptr].name_field);
  print(" at line "); print_int(line);
  interaction:=scroll_mode; jump_out;
@y
"E": if base_ptr>0 then if input_stack[base_ptr].name_field>=256 then
    begin edit_name_start:=str_start[edit_file.name_field];
    edit_name_length:=str_start[edit_file.name_field+1] -
                      str_start[edit_file.name_field];
    edit_line:=line;
    jump_out;
@z

@x [6.93] l.2062 - Declare fatal_error as noreturn.
procedure fatal_error(@!s:str_number); {prints |s|, and that's it}
@y
noreturn procedure fatal_error(@!s:str_number); {prints |s|, and that's it}
@z

@x [6.94] l.2071 - Declare overflow as noreturn.
procedure overflow(@!s:str_number;@!n:integer); {stop due to finiteness}
@y
noreturn procedure overflow(@!s:str_number;@!n:integer); {stop due to finiteness}
@z

@x [6.95] l.2090 - Declare confusion as noreturn.
procedure confusion(@!s:str_number);
@y
noreturn procedure confusion(@!s:str_number);
@z

% [7.104] `remainder' is a library routine on some systems, so change
% its name to avoid conflicts.
@x [7.104] l.2248 - avoid name conflicts with lib routine remainder()
|remainder|, holds the remainder after a division.

@<Glob...@>=
@y
|remainder|, holds the remainder after a division.

@d remainder==tex_remainder

@<Glob...@>=
@z

@x [7.109] l.2373 - Define glue_ratio in C.
@!glue_ratio=real; {one-word representation of a glue expansion factor}
@y
@z

% [8.110] Make it easy to change constants.  Do not increase
% max_quarterword without changing the memoryword structure in `texmfmem.h'.
@x [8.110] l.2428 - increase |max_halfword|
@d min_halfword==0 {smallest allowable value in a |halfword|}
@d max_halfword==65535 {largest allowable value in a |halfword|}
@y
@d min_halfword==-@"FFFFFFF {smallest allowable value in a |halfword|}
@d max_halfword==@"FFFFFFF {largest allowable value in a |halfword|}
@z

@x [8.111] l.2441 - min_halfword and max_halfword
if (mem_min<min_halfword)or(mem_max>=max_halfword)or@|
  (mem_bot-mem_min>max_halfword+1) then bad:=14;
@y
if (mem_bot-sup_main_memory<min_halfword)or@|
  (mem_top+sup_main_memory>=max_halfword) then bad:=14;
@z

@x [8.111] l.2443 - max_font_max
if (font_base<min_quarterword)or(font_max>max_quarterword) then bad:=15;
if font_max>font_base+256 then bad:=16;
@y
if (max_font_max<min_halfword)or(max_font_max>max_halfword) then bad:=15;
if font_max>font_base+max_font_max then bad:=16;
@z

@x [8.112] l.2456 - Efficiency.
macros are simplified in the obvious way when |min_quarterword=0|.
@^inner loop@>@^system dependencies@>

@d qi(#)==#+min_quarterword
  {to put an |eight_bits| item into a quarterword}
@d qo(#)==#-min_quarterword
  {to take an |eight_bits| item out of a quarterword}
@d hi(#)==#+min_halfword
  {to put a sixteen-bit item into a halfword}
@d ho(#)==#-min_halfword
  {to take a sixteen-bit item from a halfword}
@y
macros are simplified in the obvious way when |min_quarterword=0|.
So they have been simplified here in the obvious way.
@^inner loop@>@^system dependencies@>

The \.{WEB} source for \TeX\ defines |hi(#)==#+min_halfword| which can be
simplified when |min_halfword=0|.  The Web2C implementation of \TeX\ can use
|hi(#)==#| together with |min_halfword<0| as long as |max_halfword| is
sufficiently large.

@d qi(#)==# {to put an |eight_bits| item into a quarterword}
@d qo(#)==# {to take an |eight_bits| item from a quarterword}
@d hi(#)==# {to put a sixteen-bit item into a halfword}
@d ho(#)==# {to take a sixteen-bit item from a halfword}
@z

% [8.113] We've put the memory structure into the include file
% `texmf.h', since it's too hard to translate automatically.
@x [8.113] l.2474 - data structures for main memory
@!quarterword = min_quarterword..max_quarterword; {1/4 of a word}
@!halfword=min_halfword..max_halfword; {1/2 of a word}
@!two_choices = 1..2; {used when there are two variants in a record}
@!four_choices = 1..4; {used when there are four variants in a record}
@!two_halves = packed record@;@/
  @!rh:halfword;
  case two_choices of
  1: (@!lh:halfword);
  2: (@!b0:quarterword; @!b1:quarterword);
  end;
@!four_quarters = packed record@;@/
  @!b0:quarterword;
  @!b1:quarterword;
  @!b2:quarterword;
  @!b3:quarterword;
  end;
@!memory_word = record@;@/
  case four_choices of
  1: (@!int:integer);
  2: (@!gr:glue_ratio);
  3: (@!hh:two_halves);
  4: (@!qqqq:four_quarters);
  end;
@y
@!quarterword = min_quarterword..max_quarterword;
@!halfword = min_halfword..max_halfword;
@!two_choices = 1..2; {used when there are two variants in a record}
@!four_choices = 1..4; {used when there are four variants in a record}
@=#include "texmfmem.h";@>
@z

% [9.116] Change `mem' to `zmem', so we can define mem to be a register
% pointer to the memory array for speed.
@x [9.116] l.2566 - definition of main memory array
@!mem : array[mem_min..mem_max] of memory_word; {the big dynamic storage area}
@y
@!yzmem : ^memory_word; {the big dynamic storage area}
@!zmem : ^memory_word; {the big dynamic storage area}
@z

@x [10.144] l.3027 - font numbers can be >255 now.
@p function new_ligature(@!f,@!c:quarterword; @!q:pointer):pointer;
@y
@p function new_ligature(@!f:internal_font_number; @!c:quarterword;
                         @!q:pointer):pointer;
@z

% [11.165] Fix the word `free' so that it doesn't conflict with the
% standard C library routine of the same name.
@x [11.165] l.3385 - avoid conflict with lib function free()
are debugging.)
@y
are debugging.)

@d free==free_arr
@z

@x [11.165] l.3388 - dummy |free| and |was_free| arrays
@!debug @!free: packed array [mem_min..mem_max] of boolean; {free cells}
@t\hskip10pt@>@!was_free: packed array [mem_min..mem_max] of boolean;
@y
 {The debug memory arrays have not been mallocated yet.}
@!debug @!free: packed array [0..9] of boolean; {free cells}
@t\hskip10pt@>@!was_free: packed array [0..9] of boolean;
@z

@x [12.174] l.3547 - Eliminate unsigned comparisons to zero.
        begin if (font(p)<font_base)or(font(p)>font_max) then
@y
        begin if (font(p)>font_max) then
@z

@x [12.176] l.3584 - Eliminate unsigned comparisons to zero.
@p procedure print_font_and_char(@!p:integer); {prints |char_node| data}
begin if p>mem_end then print_esc("CLOBBERED.")
else  begin if (font(p)<font_base)or(font(p)>font_max) then print_char("*")
@y
@p procedure print_font_and_char(@!p:integer); {prints |char_node| data}
begin if p>mem_end then print_esc("CLOBBERED.")
else  begin if (font(p)>font_max) then print_char("*")
@z

@x [12.186] l.3768 - Don't worry about strange floating point values.
  if abs(mem[p+glue_offset].int)<@'4000000 then print("?.?")
  else if abs(g)>float_constant(20000) then
@y
  { The Unix |pc| folks removed this restriction with a remark that
    invalid bit patterns were vanishingly improbable, so we follow
    their example without really understanding it.
  |if abs(mem[p+glue_offset].int)<@'4000000 then print('?.?')|
  |else| }
  if fabs(g)>float_constant(20000) then
@z


@x [15.209] l.4186 - MLTeX: \charsubdef primitive
@d shorthand_def=95 {code definition ( \.{\\chardef}, \.{\\countdef}, etc.~)}
@y
@d shorthand_def=95 {code definition ( \.{\\chardef}, \.{\\countdef}, etc.~)}
  {or \.{\\charsubdef}}
@z

% i18n fix: messages printed by print_mode in [16.211] and [46.1049]
% can not be translated. For example, messages printed by |print_mode|
% from [16.211] use different word order and [46.1049] use different
% word order and words are declined.
@x [16.211] l.4259
begin if m>0 then
  case m div (max_command+1) of
  0:print("vertical");
  1:print("horizontal");
  2:print("display math");
  end
else if m=0 then print("no")
else  case (-m) div (max_command+1) of
  0:print("internal vertical");
  1:print("restricted horizontal");
  2:print("math");
  end;
print(" mode");
end;
@y
begin if m>0 then
  case m div (max_command+1) of
  0:print("vertical mode");
  1:print("horizontal mode");
  2:print("display math mode");
  end
else if m=0 then print("no mode")
else  case (-m) div (max_command+1) of
  0:print("internal vertical mode");
  1:print("restricted horizontal mode");
  2:print("math mode");
  end;
end;

procedure print_in_mode(@!m:integer); {prints the mode represented by |m|}
begin if m>0 then
  case m div (max_command+1) of
  0:print("' in vertical mode");
  1:print("' in horizontal mode");
  2:print("' in display math mode");
  end
else if m=0 then print("' in no mode")
else  case (-m) div (max_command+1) of
  0:print("' in internal vertical mode");
  1:print("' in restricted horizontal mode");
  2:print("' in math mode");
  end;
end;
@z

@x [16.213] l.4342 - texarray
@!nest:array[0..nest_size] of list_state_record;
@y
@!nest:^list_state_record;
@z

@x [16.215] l.4365 - reference from initialize.
prev_graf:=0; shown_mode:=0;
@<Start a new current page@>;
@y
prev_graf:=0; shown_mode:=0;
@/{The following piece of code is a copy of module 991:}
page_contents:=empty; page_tail:=page_head; {|link(page_head):=null;|}@/
last_glue:=max_halfword; last_penalty:=0; last_kern:=0;
page_depth:=0; page_max_depth:=0;
@z

@x [16.219] l.4430 - i18n fix
    print_int(nest[p].pg_field); print(" line");
    if nest[p].pg_field<>1 then print_char("s");
@y
    print_int(nest[p].pg_field);
    if nest[p].pg_field<>1 then print(" lines")
    else print(" line");
@z

@x [17.220] l.4469 - MLTeX: char_sub_code_base
paragraph shape.
@y
paragraph shape.
Additionally region~4 contains the table with ML\TeX's character
substitution definitions.
@z

@x [17.222] l.4543 - frozen_special, for source specials.
@d frozen_null_font=frozen_control_sequence+10
@y
@d frozen_special=frozen_control_sequence+10
  {permanent `\.{\\special}'}
@d frozen_null_font=frozen_control_sequence+11
@z

@x [17.222] l.4547 - max_font_max
@d undefined_control_sequence=frozen_null_font+257 {dummy location}
@y
@d undefined_control_sequence=frozen_null_font+max_font_max+1 {dummy location}
@z

@x [17.222] l.4554 - hash_extra
for k:=active_base to undefined_control_sequence-1 do
  eqtb[k]:=eqtb[undefined_control_sequence];
@y
for k:=active_base to eqtb_top do
  eqtb[k]:=eqtb[undefined_control_sequence];
@z

@x [17.230] l.4752 - MLTeX: char_sub_code_base
@d int_base=math_code_base+256 {beginning of region 5}
@y
@d char_sub_code_base=math_code_base+256 {table of character substitutions}
@d int_base=char_sub_code_base+256 {beginning of region 5}
@z

@x [17.230] l.4773 - MLTeX: char_sub_code_base
  {Note: |math_code(c)| is the true math code plus |min_halfword|}
@y
  {Note: |math_code(c)| is the true math code plus |min_halfword|}
@d char_sub_code(#)==equiv(char_sub_code_base+#)
  {Note: |char_sub_code(c)| is the true substitution info plus |min_halfword|}
@z

% MLTeX: \charsubdefmax and \tracingcharsubdef
@x [17.236] l.4975
@d int_pars=55 {total number of integer parameters}
@y
@d tex_int_pars=55 {total number of \TeX's integer parameters}
@#
@d web2c_int_base=tex_int_pars {base for web2c's integer parameters}
@d char_sub_def_min_code=web2c_int_base {smallest value in the charsubdef list}
@d char_sub_def_max_code=web2c_int_base+1 {largest value in the charsubdef list}
@d tracing_char_sub_def_code=web2c_int_base+2 {traces changes to a charsubdef def}
@d web2c_int_pars=web2c_int_base+3 {total number of web2c's integer parameters}
@#
@d int_pars=web2c_int_pars {total number of integer parameters}
@z

% MLTeX: \charsubdefmax and \tracingcharsubdef
@x [17.236] l.5037
@d error_context_lines==int_par(error_context_lines_code)
@y
@d error_context_lines==int_par(error_context_lines_code)
@#
@d char_sub_def_min==int_par(char_sub_def_min_code)
@d char_sub_def_max==int_par(char_sub_def_max_code)
@d tracing_char_sub_def==int_par(tracing_char_sub_def_code)
@z

% MLTeX: \charsubdefmax and \tracingcharsubdef
@x [17.237] l.5101
error_context_lines_code:print_esc("errorcontextlines");
@y
error_context_lines_code:print_esc("errorcontextlines");
char_sub_def_min_code:print_esc("charsubdefmin");
char_sub_def_max_code:print_esc("charsubdefmax");
tracing_char_sub_def_code:print_esc("tracingcharsubdef");
@z

% MLTeX: \charsubdefmax and \tracingcharsubdef
@x [17.238] l.5221
@!@:error_context_lines_}{\.{\\errorcontextlines} primitive@>
@y
@!@:error_context_lines_}{\.{\\errorcontextlines} primitive@>
if mltex_p then
  begin mltex_enabled_p:=true;  {enable character substitution}
  if false then {remove the if-clause to enable \.{\\charsubdefmin}}
  primitive("charsubdefmin",assign_int,int_base+char_sub_def_min_code);@/
@!@:char_sub_def_min_}{\.{\\charsubdefmin} primitive@>
  primitive("charsubdefmax",assign_int,int_base+char_sub_def_max_code);@/
@!@:char_sub_def_max_}{\.{\\charsubdefmax} primitive@>
  primitive("tracingcharsubdef",assign_int,int_base+tracing_char_sub_def_code);@/
@!@:tracing_char_sub_def_}{\.{\\tracingcharsubdef} primitive@>
  end;
@z

@x [17.240] l.5234 - MLTeX: \charsubdefmax and \tracingcharsubdef
for k:=int_base to del_code_base-1 do eqtb[k].int:=0;
@y
for k:=int_base to del_code_base-1 do eqtb[k].int:=0;
char_sub_def_min:=256; char_sub_def_max:=-1;
{allow \.{\\charsubdef} for char 0}@/
{|tracing_char_sub_def:=0| is already done}@/
@z

@x [17.241] l.5240 - Do `fix_date_and_time' in C.
@ The following procedure, which is called just before \TeX\ initializes its
input and output, establishes the initial values of the date and time.
@^system dependencies@>
Since standard \PASCAL\ cannot provide such information, something special
is needed. The program here simply assumes that suitable values appear in
the global variables \\{sys\_time}, \\{sys\_day}, \\{sys\_month}, and
\\{sys\_year} (which are initialized to noon on 4 July 1776,
in case the implementor is careless).

@p procedure fix_date_and_time;
begin sys_time:=12*60;
sys_day:=4; sys_month:=7; sys_year:=1776;  {self-evident truths}
@y
@ The following procedure, which is called just before \TeX\ initializes
its input and output, establishes the initial values of the date and
time. It calls a |date_and_time| C macro (a.k.a.\ |dateandtime|), which
calls the C function |get_date_and_time|, passing it the addresses of
|sys_time|, etc., so they can be set by the routine. |get_date_and_time|
also sets up interrupt catching if that is conditionally compiled in the
C code.

We have to initialize the |sys_| variables because that is what gets
output on the first line of the log file. (New in 2021.)
@^system dependencies@>

@p procedure fix_date_and_time;
begin date_and_time(sys_time,sys_day,sys_month,sys_year);
@z

@x [17.252] l.5447 - hash_extra
else if n<glue_base then @<Show equivalent |n|, in region 1 or 2@>
@y
else if (n<glue_base) or ((n>eqtb_size)and(n<=eqtb_top)) then
  @<Show equivalent |n|, in region 1 or 2@>
@z

@x [17.253] l.5462 - Change eqtb to zeqtb.
@!eqtb:array[active_base..eqtb_size] of memory_word;
@y
@!zeqtb:^memory_word;
@z

@x [18.256] l.5510 - hash_extra
@!hash: array[hash_base..undefined_control_sequence-1] of two_halves;
  {the hash table}
@!hash_used:pointer; {allocation pointer for |hash|}
@y
@!hash: ^two_halves; {the hash table}
@!yhash: ^two_halves; {auxiliary pointer for freeing hash}
@!hash_used:pointer; {allocation pointer for |hash|}
@!hash_extra:pointer; {|hash_extra=hash| above |eqtb_size|}
@!hash_top:pointer; {maximum of the hash array}
@!eqtb_top:pointer; {maximum of the |eqtb|}
@!hash_high:pointer; {pointer to next high hash location}
@z

@x [18.257] l.5518 - hash_extra
next(hash_base):=0; text(hash_base):=0;
for k:=hash_base+1 to undefined_control_sequence-1 do hash[k]:=hash[hash_base];
@y
@z

@x [18.258] l.5522 - hash_extra
hash_used:=frozen_control_sequence; {nothing is used}
@y
hash_used:=frozen_control_sequence; {nothing is used}
hash_high:=0;
@z

@x [18.260] l.5558 - hash_extra
@ @<Insert a new control...@>=
begin if text(p)>0 then
  begin repeat if hash_is_full then overflow("hash size",hash_size);
@:TeX capacity exceeded hash size}{\quad hash size@>
  decr(hash_used);
  until text(hash_used)=0; {search for an empty location in |hash|}
  next(p):=hash_used; p:=hash_used;
  end;
@y
@ @<Insert a new control...@>=
begin if text(p)>0 then
  begin if hash_high<hash_extra then
      begin incr(hash_high);
      next(p):=hash_high+eqtb_size; p:=hash_high+eqtb_size;
      end
    else begin
      repeat if hash_is_full then overflow("hash size",hash_size+hash_extra);
@:TeX capacity exceeded hash size}{\quad hash size@>
      decr(hash_used);
      until text(hash_used)=0; {search for an empty location in |hash|}
    next(p):=hash_used; p:=hash_used;
    end;
  end;
@z

@x [18.262] l.5610 - hash_extra
else if p>=undefined_control_sequence then print_esc("IMPOSSIBLE.")
@y
else if ((p>=undefined_control_sequence)and(p<=eqtb_size))or(p>eqtb_top) then
  print_esc("IMPOSSIBLE.")
@z

@x [18.262] l.5611 - Remove more unsigned comparisons to zero.
else if (text(p)<0)or(text(p)>=str_ptr) then print_esc("NONEXISTENT.")
@y
else if (text(p)>=str_ptr) then print_esc("NONEXISTENT.")
@z

@x [19.271] l.5899 - texarray
@!save_stack : array[0..save_size] of memory_word;
@y
@!save_stack : ^memory_word;
@z

@x [19.283] l.6077 - hash_extra
if p<int_base then
@y
if (p<int_base)or(p>eqtb_size) then
@z

@x [20.290] l.6185 - hash_extra
if cs_token_flag+undefined_control_sequence>max_halfword then bad:=21;
@y
if cs_token_flag+eqtb_size+hash_extra>max_halfword then bad:=21;
if (hash_offset<0)or(hash_offset>hash_base) then bad:=42;
@z

@x [22.301] l.6459 - texarray
@!input_stack : array[0..stack_size] of in_state_record;
@y
@!input_stack : ^in_state_record;
@z

@x [22.304] l.6563 - texarray; additions for file:line:error style.
@!input_file : array[1..max_in_open] of alpha_file;
@!line : integer; {current line number in the current source file}
@!line_stack : array[1..max_in_open] of integer;
@y
@!input_file : ^alpha_file;
@!line : integer; {current line number in the current source file}
@!line_stack : ^integer;
@!source_filename_stack : ^str_number;
@!full_source_filename_stack : ^str_number;
@z

@x [22.306] l.6615 - i18n fix
  begin print_nl("Runaway ");
@.Runaway...@>
  case scanner_status of
  defining: begin print("definition"); p:=def_ref;
    end;
  matching: begin print("argument"); p:=temp_head;
    end;
  aligning: begin print("preamble"); p:=hold_head;
    end;
  absorbing: begin print("text"); p:=def_ref;
    end;
  end; {there are no other cases}
@y
  begin
@.Runaway...@>
  case scanner_status of
  defining: begin print_nl("Runaway definition"); p:=def_ref;
    end;
  matching: begin print_nl("Runaway argument"); p:=temp_head;
    end;
  aligning: begin print_nl("Runaway preamble"); p:=hold_head;
    end;
  absorbing: begin print_nl("Runaway text"); p:=def_ref;
    end;
  end; {there are no other cases}
@z

@x [22.308] l.6728 - texarray
@!param_stack:array [0..param_size] of pointer;
  {token list pointers for parameters}
@y
@!param_stack: ^pointer;
  {token list pointers for parameters}
@z

@x [23.328] l.7064 - keep top of source_filename_stack initialized
incr(in_open); push_input; index:=in_open;
@y
incr(in_open); push_input; index:=in_open;
source_filename_stack[index]:=0;full_source_filename_stack[index]:=0;
@z

@x [23.331] l.7092 - init source file name stacks
begin input_ptr:=0; max_in_stack:=0;
@y
begin input_ptr:=0; max_in_stack:=0;
source_filename_stack[0]:=0;full_source_filename_stack[0]:=0;
@z

% Original report: https://tug.org/pipermail/tex-k/2024-March/004021.html
% TeX bug entry:   https://tug.org/texmfbug/newbug.html#B142outer
@x [24.336] l.7152 - allow interactive deletion of \outer token
begin if scanner_status<>normal then
@y
begin if OK_to_interrupt and(scanner_status<>normal) then
@z

@x [24.338] l.7191 - i18n fix
print(" while scanning ");
@y
@z

@x [24.339] l.7213 - i18n fix
defining:begin print("definition"); info(p):=right_brace_token+"}";
  end;
matching:begin print("use"); info(p):=par_token; long_state:=outer_call;
  end;
aligning:begin print("preamble"); info(p):=right_brace_token+"}"; q:=p;
  p:=get_avail; link(p):=q; info(p):=cs_token_flag+frozen_cr;
  align_state:=-1000000;
  end;
absorbing:begin print("text"); info(p):=right_brace_token+"}";
@y
defining:begin print(" while scanning definition"); info(p):=right_brace_token+"}";
  end;
matching:begin print(" while scanning use"); info(p):=par_token; long_state:=outer_call;
  end;
aligning:begin print(" while scanning preamble"); info(p):=right_brace_token+"}"; q:=p;
  p:=get_avail; link(p):=q; info(p):=cs_token_flag+frozen_cr;
  align_state:=-1000000;
  end;
absorbing:begin print(" while scanning text"); info(p):=right_brace_token+"}";
@z

@x [25.366] l.7672 - expansion depth overflow
begin cv_backup:=cur_val; cvl_backup:=cur_val_level; radix_backup:=radix;
@y
begin
incr(expand_depth_count);
if expand_depth_count>=expand_depth then overflow("expansion depth",expand_depth);
cv_backup:=cur_val; cvl_backup:=cur_val_level; radix_backup:=radix;
@z

@x [25.366] l.7678 - expansion depth overflow
cur_order:=co_backup; link(backup_head):=backup_backup;
@y
cur_order:=co_backup; link(backup_head):=backup_backup;
decr(expand_depth_count);
@z

% Original report: https://tex.stackexchange.com/questions/609423
% TeX bug entry: https://tug.org/texmfbug/newbug.html#B155endwrite
@x [25.369] l.7717 - disallow \noexpand\endwrite
if t>=cs_token_flag then
@y
if (t>=cs_token_flag)and(t<>end_write_token) then
@z

@x [27.484] l.9495 - set limit when fatal_error
else fatal_error("*** (cannot \read from terminal in nonstop modes)")
@y
else begin
  limit:=0;
  fatal_error("*** (cannot \read from terminal in nonstop modes)");
  end
@z

@x [28.501] l.9765 - \eof18
if_eof_code: begin scan_four_bit_int; b:=(read_open[cur_val]=closed);
  end;
@y
if_eof_code: begin scan_four_bit_int_or_18;
  if cur_val=18 then b:=not shellenabledp
  else b:=(read_open[cur_val]=closed);
  end;
@z

@x [29.513] l.9983 - Area and extension rules for filenames.
@ The file names we shall deal with for illustrative purposes have the
following structure:  If the name contains `\.>' or `\.:', the file area
consists of all characters up to and including the final such character;
otherwise the file area is null.  If the remaining file name contains
`\..', the file extension consists of all such characters from the first
remaining `\..' to the end, otherwise the file extension is null.
@y
@ The file names we shall deal with have the
following structure:  If the name contains `\./' or `\.:'
(for Amiga only), the file area
consists of all characters up to and including the final such character;
otherwise the file area is null.  If the remaining file name contains
`\..', the file extension consists of all such characters from the last
`\..' to the end, otherwise the file extension is null.
@z

@x [29.513] l.9995 - Area and extension rules for filenames.
@!area_delimiter:pool_pointer; {the most recent `\.>' or `\.:', if any}
@!ext_delimiter:pool_pointer; {the relevant `\..', if any}
@y
@!area_delimiter:pool_pointer; {the most recent `\./', if any}
@!ext_delimiter:pool_pointer; {the most recent `\..', if any}
@z

@x [29.514] l.10005 - TeX area directories.
@d TEX_area=="TeXinputs:"
@.TeXinputs@>
@d TEX_font_area=="TeXfonts:"
@.TeXfonts@>
@y
In C, the default paths are specified separately.
@z

@x [29.515] l.10014 - filenames: quoted
begin area_delimiter:=0; ext_delimiter:=0;
@y
begin area_delimiter:=0; ext_delimiter:=0; quoted_filename:=false;
@z

@x [29.516] l.10024 - filenames: more_name
begin if c=" " then more_name:=false
@y
begin if (c=" ") and stop_at_space and (not quoted_filename) then
  more_name:=false
else  if c="""" then begin
  quoted_filename:=not quoted_filename;
  more_name:=true;
  end
@z

@x [29.516] l.10026 - filenames: more_name
  if (c=">")or(c=":") then
@y
  if IS_DIR_SEP(c) then
@z

@x [29.516] l.10029 - filenames: more_name
  else if (c=".")and(ext_delimiter=0) then ext_delimiter:=cur_length;
@y
  else if c="." then ext_delimiter:=cur_length;
@z

@x [29.517] l.10034 - end_name: string recycling
@ The third.
@^system dependencies@>

@p procedure end_name;
@y
@ The third.
@^system dependencies@>
If a string is already in the string pool, the function
|slow_make_string| does not create a new string but returns this string
number, thus saving string space.  Because of this new property of the
returned string number it is not possible to apply |flush_string| to
these strings.

@p procedure end_name;
var temp_str: str_number; {result of file name cache lookups}
@!j,@!s,@!t: pool_pointer; {running indices}
@!must_quote:boolean; {whether we need to quote a string}
@z

@x [29.517] l.10040 - end_name: spaces in filenames
@:TeX capacity exceeded number of strings}{\quad number of strings@>
@y
@:TeX capacity exceeded number of strings}{\quad number of strings@>
str_room(6); {Room for quotes, if needed.}
{add quotes if needed}
if area_delimiter<>0 then begin
  {maybe quote |cur_area|}
  must_quote:=false;
  s:=str_start[str_ptr];
  t:=str_start[str_ptr]+area_delimiter;
  j:=s;
  while (not must_quote) and (j<t) do begin
    must_quote:=str_pool[j]=" "; incr(j);
    end;
  if must_quote then begin
    for j:=pool_ptr-1 downto t do str_pool[j+2]:=str_pool[j];
    str_pool[t+1]:="""";
    for j:=t-1 downto s do str_pool[j+1]:=str_pool[j];
    str_pool[s]:="""";
    if ext_delimiter<>0 then ext_delimiter:=ext_delimiter+2;
    area_delimiter:=area_delimiter+2;
    pool_ptr:=pool_ptr+2;
    end;
  end;
{maybe quote |cur_name|}
s:=str_start[str_ptr]+area_delimiter;
if ext_delimiter=0 then t:=pool_ptr else t:=str_start[str_ptr]+ext_delimiter-1;
must_quote:=false;
j:=s;
while (not must_quote) and (j<t) do begin
  must_quote:=str_pool[j]=" "; incr(j);
  end;
if must_quote then begin
  for j:=pool_ptr-1 downto t do str_pool[j+2]:=str_pool[j];
  str_pool[t+1]:="""";
  for j:=t-1 downto s do str_pool[j+1]:=str_pool[j];
  str_pool[s]:="""";
  if ext_delimiter<>0 then ext_delimiter:=ext_delimiter+2;
  pool_ptr:=pool_ptr+2;
  end;
if ext_delimiter<>0 then begin
  {maybe quote |cur_ext|}
  s:=str_start[str_ptr]+ext_delimiter-1;
  t:=pool_ptr;
  must_quote:=false;
  j:=s;
  while (not must_quote) and (j<t) do begin
    must_quote:=str_pool[j]=" "; incr(j);
    end;
  if must_quote then begin
    str_pool[t+1]:="""";
    for j:=t-1 downto s do str_pool[j+1]:=str_pool[j];
    str_pool[s]:="""";
    pool_ptr:=pool_ptr+2;
    end;
  end;
@z

@x [29.517] l.10044 - end_name: string recycling
  end;
if ext_delimiter=0 then
  begin cur_ext:=""; cur_name:=make_string;
@y
  temp_str:=search_string(cur_area);
  if temp_str>0 then
    begin cur_area:=temp_str;
    decr(str_ptr);  {no |flush_string|, |pool_ptr| will be wrong!}
    for j:=str_start[str_ptr+1] to pool_ptr-1 do
      begin str_pool[j-area_delimiter]:=str_pool[j];
      end;
    pool_ptr:=pool_ptr-area_delimiter; {update |pool_ptr|}
    end;
  end;
if ext_delimiter=0 then
  begin cur_ext:=""; cur_name:=slow_make_string;
@z

@x [29.517] l.10050 - end_name: string recycling
  incr(str_ptr); cur_ext:=make_string;
@y
  incr(str_ptr); cur_ext:=make_string;
  decr(str_ptr); {undo extension string to look at name part}
  temp_str:=search_string(cur_name);
  if temp_str>0 then
    begin cur_name:=temp_str;
    decr(str_ptr);  {no |flush_string|, |pool_ptr| will be wrong!}
    for j:=str_start[str_ptr+1] to pool_ptr-1 do
      begin str_pool[j-ext_delimiter+area_delimiter+1]:=str_pool[j];
      end;
    pool_ptr:=pool_ptr-ext_delimiter+area_delimiter+1;  {update |pool_ptr|}
    end;
  cur_ext:=slow_make_string;  {remake extension string}
@z

@x [29.518] l.10056 - print_file_name: quote if spaces in names.
some operating systems put the file area last instead of first.)
@^system dependencies@>
@y
some operating systems put the file area last instead of first.)
@^system dependencies@>

@d check_quoted(#) == {check if string |#| needs quoting}
if #<>0 then begin
  j:=str_start[#];
  while (not must_quote) and (j<str_start[#+1]) do begin
    must_quote:=str_pool[j]=" "; incr(j);
  end;
end
@#
@d print_quoted(#) == {print string |#|, omitting quotes}
if #<>0 then
  for j:=str_start[#] to str_start[#+1]-1 do
    if so(str_pool[j])<>"""" then
      print(so(str_pool[j]))
@z

@x [29.518] l.10061 - print_file_name: quote if spaces in names.
begin slow_print(a); slow_print(n); slow_print(e);
@y
var must_quote: boolean; {whether to quote the filename}
@!j:pool_pointer; {index into |str_pool|}
begin
must_quote:=false;
check_quoted(a); check_quoted(n); check_quoted(e);
{FIXME: Alternative is to assume that any filename that has to be quoted has
 at least one quoted component...if we pick this, a number of insertions
 of |print_file_name| should go away.
|must_quote|:=((|a|<>0)and(|str_pool|[|str_start|[|a|]]=""""))or
              ((|n|<>0)and(|str_pool|[|str_start|[|n|]]=""""))or
              ((|e|<>0)and(|str_pool|[|str_start|[|e|]]=""""));}
if must_quote then print_char("""");
print_quoted(a); print_quoted(n); print_quoted(e);
if must_quote then print_char("""");
@z

@x [29.519] l.10070 - have append_to_name skip quotes.
@d append_to_name(#)==begin c:=#; incr(k);
  if k<=file_name_size then name_of_file[k]:=xchr[c];
  end
@y
@d append_to_name(#)==begin c:=#; if not (c="""") then begin incr(k);
  if k<=file_name_size then name_of_file[k]:=xchr[c];
  end end
@z

% [29.519] In pack_file_name, leave room for the extra null we append at
% the end of a filename.
@x [29.519] l.10078 - pack_file_name, leave room for the extra null
begin k:=0;
@y
begin k:=0;
if name_of_file then libc_free (name_of_file);
name_of_file:= xmalloc_array (ASCII_code, length(a)+length(n)+length(e)+1);
@z

@x [29.519] l.10083 - pack_file_name, append the extra null
for k:=name_length+1 to file_name_size do name_of_file[k]:=' ';
@y
name_of_file[name_length+1]:=0;
@z

@x [29.520] l.10092 - filenames: default format.
@d format_default_length=20 {length of the |TEX_format_default| string}
@d format_area_length=11 {length of its area part}
@d format_ext_length=4 {length of its `\.{.fmt}' part}
@y
Under {\mc UNIX} we don't give the area part, instead depending
on the path searching that will happen during file opening.  Also, the
length will be set in the main program.

@d format_area_length=0 {length of its area part}
@d format_ext_length=4 {length of its `\.{.fmt}' part}
@z

@x [29.520] l.10098 - filenames: default format, where `plain.fmt' is.
@!TEX_format_default:packed array[1..format_default_length] of char;

@ @<Set init...@>=
TEX_format_default:='TeXformats:plain.fmt';
@y
@!format_default_length: integer;
@!TEX_format_default: cstring;

@ We set the name of the default format file and the length of that name
in C, instead of Pascal, since we want them to depend on the name of the
program.
@z

@x [29.523] l.10127 - Change to pack_buffered_name as with pack_file_name.
for j:=1 to n do append_to_name(xord[TEX_format_default[j]]);
for j:=a to b do append_to_name(buffer[j]);
for j:=format_default_length-format_ext_length+1 to format_default_length do
  append_to_name(xord[TEX_format_default[j]]);
if k<=file_name_size then name_length:=k@+else name_length:=file_name_size;
for k:=name_length+1 to file_name_size do name_of_file[k]:=' ';
@y
if name_of_file then libc_free (name_of_file);
name_of_file := xmalloc_array (ASCII_code, n+(b-a+1)+format_ext_length+1);
for j:=1 to n do append_to_name(xord[ucharcast(TEX_format_default[j])]);
for j:=a to b do append_to_name(buffer[j]);
for j:=format_default_length-format_ext_length+1 to format_default_length do
  append_to_name(xord[ucharcast(TEX_format_default[j])]);
if k<=file_name_size then name_length:=k@+else name_length:=file_name_size;
name_of_file[name_length+1]:=0;
@z

@x [29.524] l.10150 - Format file opening: only try once, with path searching.
  pack_buffered_name(0,loc,j-1); {try first without the system file area}
  if w_open_in(fmt_file) then goto found;
  pack_buffered_name(format_area_length,loc,j-1);
    {now try the system format file area}
  if w_open_in(fmt_file) then goto found;
@y
  pack_buffered_name(0,loc,j-1); {Kpathsea does everything}
  if w_open_in(fmt_file) then goto found;
@z

@x [29.524] l.10156 - replace `PLAIN' in error messages with `default'.
  wterm_ln('Sorry, I can''t find that format;',' will try PLAIN.');
@y
  wterm ('Sorry, I can''t find the format `');
  fputs (stringcast(name_of_file + 1), stdout);
  wterm ('''; will try `');
  fputs (TEX_format_default + 1, stdout);
  wterm_ln ('''.');
@z

@x [29.524] l.10164 - replace `PLAIN' in error messages with `default'.
  wterm_ln('I can''t find the PLAIN format file!');
@.I can't find PLAIN...@>
@y
  wterm ('I can''t find the format file `');
  fputs (TEX_format_default + 1, stdout);
  wterm_ln ('''!');
@.I can't find the format...@>
@z

@x [29.525] l.10184 - make_name_string
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
@y
save_area_delimiter, save_ext_delimiter: pool_pointer;
save_name_in_progress, save_stop_at_space: boolean;
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
@z

@x [29.525] l.10188 - make_name_string
  make_name_string:=make_string;
@y
  make_name_string:=make_string;
  {At this point we also set |cur_name|, |cur_ext|, and |cur_area| to
   match the contents of |name_of_file|.}
  save_area_delimiter:=area_delimiter; save_ext_delimiter:=ext_delimiter;
  save_name_in_progress:=name_in_progress; save_stop_at_space:=stop_at_space;
  name_in_progress:=true;
  begin_name;
  stop_at_space:=false;
  k:=1;
  while (k<=name_length)and(more_name(name_of_file[k])) do
    incr(k);
  stop_at_space:=save_stop_at_space;
  end_name;
  name_in_progress:=save_name_in_progress;
  area_delimiter:=save_area_delimiter; ext_delimiter:=save_ext_delimiter;
@z

@x [29.526] l.10206 - look for a left_brace when scanning a file name
@p procedure scan_file_name;
label done;
@y
@p procedure scan_file_name;
label done;
var
  @!save_warning_index: pointer;
begin
  save_warning_index := warning_index;
  warning_index := cur_cs; {store |cur_cs| here to remember until later}
  @<Get the next non-blank non-relax non-call...@>; {here the program expands
    tokens and removes spaces and \.{\\relax}es from the input. The \.{\\relax}
    removal follows LuaTeX''s implementation, and other cases of
    balanced text scanning.}
  back_input; {return the last token to be read by either code path}
  if cur_cmd=left_brace then
    scan_file_name_braced
  else
@z

@x [29.526] l.10213 - stop scanning file name if we're at end-of-line.
  if not more_name(cur_chr) then goto done;
@y
  {If |cur_chr| is a space and we're not scanning a token list, check
   whether we're at the end of the buffer. Otherwise we end up adding
   spurious spaces to file names in some cases.}
  if (cur_chr=" ") and (state<>token_list) and (loc>limit) then goto done;
  if not more_name(cur_chr) then goto done;
@z

@x [29.526] l.10216 - scan a bgroup/egroup-delimited file name
done: end_name; name_in_progress:=false;
end;
@y
  end;
done: end_name; name_in_progress:=false;
warning_index := save_warning_index; {restore |warning_index|}
end;
@z

@x [29.530] l.10264 - prompt_file_name: prevent empty filenames.
var k:0..buf_size; {index into |buffer|}
@y
var k:0..buf_size; {index into |buffer|}
@!saved_cur_name:str_number; {to catch empty terminal input}
@!saved_cur_ext:str_number; {to catch empty terminal input}
@!saved_cur_area:str_number; {to catch empty terminal input}
@z

@x [29.530] l.10271 - prompt_file_name: No default extension is TeX input file.
if e=".tex" then show_context;
@y
if (e=".tex") or (e="") then show_context;
print_ln; print_c_string(prompt_file_name_help_msg);
if (e<>"") then
  begin
    print("; default file extension is `"); print(e); print("'");
  end;
print(")"); print_ln;
@z

@x [29.530] l.10277 - prompt_file_name: prevent empty filenames.
clear_terminal; prompt_input(": "); @<Scan file name in the buffer@>;
if cur_ext="" then cur_ext:=e;
@y
saved_cur_name:=cur_name;
saved_cur_ext:=cur_ext;
saved_cur_area:=cur_area;
clear_terminal; prompt_input(": "); @<Scan file name in the buffer@>;
if (length(cur_name)=0) and (cur_ext="") and (cur_area="") then
  begin
    cur_name:=saved_cur_name;
    cur_ext:=saved_cur_ext;
    cur_area:=saved_cur_area;
  end
else
  if cur_ext="" then cur_ext:=e;
@z

@x [29.532] l.10295 - avoid conflict, `logname' in <unistd.h> on some systems.
@d ensure_dvi_open==if output_file_name=0 then
@y
@d log_name == texmf_log_name
@d ensure_dvi_open==if output_file_name=0 then
@z

@x [29.534] l.10317 - Adjust for C string conventions.
@!months:packed array [1..36] of char; {abbreviations of month names}
@y
@!months:const_cstring;
@z

@x [29.534] l.10319 - Filename change for the recorder.
if job_name=0 then job_name:="texput";
@.texput@>
@y
if job_name=0 then job_name:=get_job_name("texput");
@.texput@>
pack_job_name(".fls");
recorder_change_filename(stringcast(name_of_file+1));
@z

@x [29.534] l.10325 - MLTeX: add MLTeX banner after loading fmt file
@<Print the banner line, including the date and time@>;
@y
@<Print the banner line, including the date and time@>;
if mltex_enabled_p then
  begin wlog_cr; wlog('MLTeX v2.2 enabled');
  end;
@z

@x [29.536] l.10356
begin wlog(banner);
@y
begin
if src_specials_p or file_line_error_style_p or parse_first_line_p
then
  wlog(banner_k)
else
  wlog(banner);
@z

@x [29.536] l.10357 - Print rest of banner.
slow_print(format_ident); print("  ");
@y
wlog(version_string);
slow_print(format_ident); print("  ");
@z

@x [29.536] l.10359 - Adjust for C string conventions.
months:='JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC';
@y
months := ' JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC';
@z

% Print whether we're using src-specials and other such features.
% Print TCX name if one's given.
@x [29.536] l.10363
end
@y
if shellenabledp then begin
  wlog_cr;
  wlog(' ');
  if restrictedshell then begin
    wlog('restricted ');
  end;
  wlog('\write18 enabled.')
  end;
if src_specials_p then begin
  wlog_cr;
  wlog(' Source specials enabled.')
  end;
if file_line_error_style_p then begin
  wlog_cr;
  wlog(' file:line:error style messages enabled.')
  end;
if parse_first_line_p then begin
  wlog_cr;
  wlog(' %&-line parsing enabled.');
  end;
if translate_filename then begin
  wlog_cr;
  wlog(' (');
  fputs(translate_filename, log_file);
  wlog(')');
  end;
end
@z

% [29.537] Use a path when calling a_open_in to do a \input; also, try
% to open the file with and without the `.tex' extension, regardless of
% whether the file already has an extension.  This allows filenames like
% `foo' and `foo.bar.tex', as well as `foo.tex' and `foo.bar'.
@x [29.537] l.10373 - start_input
begin scan_file_name; {set |cur_name| to desired file name}
if cur_ext="" then cur_ext:=".tex";
pack_cur_name;
loop@+  begin begin_file_reading; {set up |cur_file| and new level of input}
  if a_open_in(cur_file) then goto done;
  if cur_area="" then
    begin pack_file_name(cur_name,TEX_area,cur_ext);
    if a_open_in(cur_file) then goto done;
    end;
@y
var temp_str: str_number;
begin scan_file_name; {set |cur_name| to desired file name}
pack_cur_name;
loop@+begin
  begin_file_reading; {set up |cur_file| and new level of input}
  tex_input_type := 1; {Tell |open_input| we are \.{\\input}.}
  {Kpathsea tries all the various ways to get the file.}
  if kpse_in_name_ok(stringcast(name_of_file+1))
     and a_open_in(cur_file, kpse_tex_format) then
    goto done;
@z

@x [29.537] l.10383 - start_input: don't force ".tex" extension.
  prompt_file_name("input file name",".tex");
@y
  prompt_file_name("input file name","");
@z

@x [29.537] l.10385 - start_input: string recycling
done: name:=a_make_name_string(cur_file);
@y
done: name:=a_make_name_string(cur_file);
source_filename_stack[in_open]:=name;
full_source_filename_stack[in_open]:=make_full_name_string;
if name=str_ptr-1 then {we can try to conserve string pool space now}
  begin temp_str:=search_string(name);
  if temp_str>0 then
    begin name:=temp_str; flush_string;
    end;
  end;
@z

@x [29.537] l.10387 - start_input: was job_name given on the command line?
  begin job_name:=cur_name; open_log_file;
@y
  begin job_name:=get_job_name(cur_name); open_log_file;
@z

@x [29.537] l.10390
if term_offset+length(name)>max_print_line-2 then print_ln
else if (term_offset>0)or(file_offset>0) then print_char(" ");
print_char("("); incr(open_parens); slow_print(name); update_terminal;
@y
if term_offset+length(full_source_filename_stack[in_open])>max_print_line-2
then print_ln
else if (term_offset>0)or(file_offset>0) then print_char(" ");
print_char("("); incr(open_parens);
slow_print(full_source_filename_stack[in_open]); update_terminal;
@z

@x [29.537] l.10394 - start_input: don't return filename to string pool.
if name=str_ptr-1 then {conserve string pool space (but see note above)}
  begin flush_string; name:=cur_name;
  end;
@y
@z

@x [30.548] l.10708 - texarray
@!internal_font_number=font_base..font_max; {|font| in a |char_node|}
@!font_index=0..font_mem_size; {index into |font_info|}
@y
@!internal_font_number=integer; {|font| in a |char_node|}
@!font_index=integer; {index into |font_info|}
@!nine_bits=min_quarterword..non_char;
@z

@x [30.549] l.10717 - texarray
@!font_info:array[font_index] of memory_word;
  {the big collection of font data}
@!fmem_ptr:font_index; {first unused word of |font_info|}
@!font_ptr:internal_font_number; {largest internal font number in use}
@!font_check:array[internal_font_number] of four_quarters; {check sum}
@!font_size:array[internal_font_number] of scaled; {``at'' size}
@!font_dsize:array[internal_font_number] of scaled; {``design'' size}
@!font_params:array[internal_font_number] of font_index; {how many font
  parameters are present}
@!font_name:array[internal_font_number] of str_number; {name of the font}
@!font_area:array[internal_font_number] of str_number; {area of the font}
@!font_bc:array[internal_font_number] of eight_bits;
  {beginning (smallest) character code}
@!font_ec:array[internal_font_number] of eight_bits;
  {ending (largest) character code}
@!font_glue:array[internal_font_number] of pointer;
  {glue specification for interword space, |null| if not allocated}
@!font_used:array[internal_font_number] of boolean;
  {has a character from this font actually appeared in the output?}
@!hyphen_char:array[internal_font_number] of integer;
  {current \.{\\hyphenchar} values}
@!skew_char:array[internal_font_number] of integer;
  {current \.{\\skewchar} values}
@!bchar_label:array[internal_font_number] of font_index;
  {start of |lig_kern| program for left boundary character,
  |non_address| if there is none}
@!font_bchar:array[internal_font_number] of min_quarterword..non_char;
  {boundary character, |non_char| if there is none}
@!font_false_bchar:array[internal_font_number] of min_quarterword..non_char;
  {|font_bchar| if it doesn't exist in the font, otherwise |non_char|}
@y
@!font_info: ^fmemory_word;
  {the big collection of font data}
@!fmem_ptr:font_index; {first unused word of |font_info|}
@!font_ptr:internal_font_number; {largest internal font number in use}
@!font_check: ^four_quarters; {check sum}
@!font_size: ^scaled; {``at'' size}
@!font_dsize: ^scaled; {``design'' size}
@!font_params: ^font_index; {how many font
  parameters are present}
@!font_name: ^str_number; {name of the font}
@!font_area: ^str_number; {area of the font}
@!font_bc: ^eight_bits;
  {beginning (smallest) character code}
@!font_ec: ^eight_bits;
  {ending (largest) character code}
@!font_glue: ^pointer;
  {glue specification for interword space, |null| if not allocated}
@!font_used: ^boolean;
  {has a character from this font actually appeared in the output?}
@!hyphen_char: ^integer;
  {current \.{\\hyphenchar} values}
@!skew_char: ^integer;
  {current \.{\\skewchar} values}
@!bchar_label: ^font_index;
  {start of |lig_kern| program for left boundary character,
  |non_address| if there is none}
@!font_bchar: ^nine_bits;
  {boundary character, |non_char| if there is none}
@!font_false_bchar: ^nine_bits;
  {|font_bchar| if it doesn't exist in the font, otherwise |non_char|}
@z

@x [30.550] l.10758 - texarray
@!char_base:array[internal_font_number] of integer;
  {base addresses for |char_info|}
@!width_base:array[internal_font_number] of integer;
  {base addresses for widths}
@!height_base:array[internal_font_number] of integer;
  {base addresses for heights}
@!depth_base:array[internal_font_number] of integer;
  {base addresses for depths}
@!italic_base:array[internal_font_number] of integer;
  {base addresses for italic corrections}
@!lig_kern_base:array[internal_font_number] of integer;
  {base addresses for ligature/kerning programs}
@!kern_base:array[internal_font_number] of integer;
  {base addresses for kerns}
@!exten_base:array[internal_font_number] of integer;
  {base addresses for extensible recipes}
@!param_base:array[internal_font_number] of integer;
  {base addresses for font parameters}
@y
@!char_base: ^integer;
  {base addresses for |char_info|}
@!width_base: ^integer;
  {base addresses for widths}
@!height_base: ^integer;
  {base addresses for heights}
@!depth_base: ^integer;
  {base addresses for depths}
@!italic_base: ^integer;
  {base addresses for italic corrections}
@!lig_kern_base: ^integer;
  {base addresses for ligature/kerning programs}
@!kern_base: ^integer;
  {base addresses for kerns}
@!exten_base: ^integer;
  {base addresses for extensible recipes}
@!param_base: ^integer;
  {base addresses for font parameters}
@z

@x [30.551] l.10778 - texarray
for k:=font_base to font_max do font_used[k]:=false;
@y
@z

@x [30.552] l.10784 - texarray
font_ptr:=null_font; fmem_ptr:=7;
font_name[null_font]:="nullfont"; font_area[null_font]:="";
hyphen_char[null_font]:="-"; skew_char[null_font]:=-1;
bchar_label[null_font]:=non_address;
font_bchar[null_font]:=non_char; font_false_bchar[null_font]:=non_char;
font_bc[null_font]:=1; font_ec[null_font]:=0;
font_size[null_font]:=0; font_dsize[null_font]:=0;
char_base[null_font]:=0; width_base[null_font]:=0;
height_base[null_font]:=0; depth_base[null_font]:=0;
italic_base[null_font]:=0; lig_kern_base[null_font]:=0;
kern_base[null_font]:=0; exten_base[null_font]:=0;
font_glue[null_font]:=null; font_params[null_font]:=7;
param_base[null_font]:=-1;
for k:=0 to 6 do font_info[k].sc:=0;
@y
@z

@x [30.554] l.10830 - MLTeX: |effective_char| in |char_info|
as fast as possible under the circumstances.
@^inner loop@>

@d char_info_end(#)==#].qqqq
@d char_info(#)==font_info[char_base[#]+char_info_end
@y
as fast as possible under the circumstances.
@^inner loop@>

ML\TeX{} will assume that a character |c| exists iff either exists in
the current font or a character substitution definition for this
character was defined using \.{\\charsubdef}.  To avoid the
distinction between these two cases, ML\TeX{} introduces the notion
``effective character'' of an input character |c|.  If |c| exists in
the current font, the effective character of |c| is the character |c|
itself.  If it doesn't exist but a character substitution is defined,
the effective character of |c| is the base character defined in the
character substitution.  If there is an effective character for a
non-existing character |c|, the ``virtual character'' |c| will get
appended to the horizontal lists.

The effective character is used within |char_info| to access
appropriate character descriptions in the font.  For example, when
calculating the width of a box, ML\TeX{} will use the metrics of the
effective characters.  For the case of a substitution, ML\TeX{} uses
the metrics of the base character, ignoring the metrics of the accent
character.

If character substitutions are changed, it will be possible that a
character |c| neither exists in a font nor there is a valid character
substitution for |c|.  To handle these cases |effective_char| should
be called with its first argument set to |true| to ensure that it
will still return an existing character in the font.  If neither |c|
nor the substituted base character in the current character
substitution exists, |effective_char| will output a warning and
return the character |font_bc[f]| (which is incorrect, but can not be
changed within the current framework).

Sometimes character substitutions are unwanted, therefore the
original definition of |char_info| can be used using the macro
|orig_char_info|.  Operations in which character substitutions should
be avoided are, for example, loading a new font and checking the font
metric information in this font, and character accesses in math mode.

@d char_list_exists(#)==(char_sub_code(#)>hi(0))
@d char_list_accent(#)==(ho(char_sub_code(#)) div 256)
@d char_list_char(#)==(ho(char_sub_code(#)) mod 256)
@#
@d char_info_end(#)== #@=)@>].qqqq
@d char_info(#)==
  font_info[char_base[#]+effective_char@=(@>true,#,char_info_end
@#
@d orig_char_info_end(#)==#].qqqq
@d orig_char_info(#)==font_info[char_base[#]+orig_char_info_end
@#
@z

@x [30.560] l.10911 - MLTeX: |effective_char| in |char_info|
@p function read_font_info(@!u:pointer;@!nom,@!aire:str_number;
@y
@p @t\4@>@<Declare additional functions for ML\TeX@>@/

function read_font_info(@!u:pointer;@!nom,@!aire:str_number;
@z

@x [30.560] l.10915 - Check lengths
@!file_opened:boolean; {was |tfm_file| successfully opened?}
@y
@!name_too_long:boolean; {|nom| or |aire| exceeds 255 bytes?}
@!file_opened:boolean; {was |tfm_file| successfully opened?}
@z

@x [30.561] l.10956 - Check lengths
else print(" not loadable: Metric (TFM) file not found");
@y
else if name_too_long then print(" not loadable: Metric (TFM) file name too long")
else print(" not loadable: Metric (TFM) file not found");
@z

@x [30.563] l.10978 - Check lengths, don't use TEX_font_area.
if aire="" then pack_file_name(nom,TEX_font_area,".tfm")
else pack_file_name(nom,aire,".tfm");
@y
name_too_long:=(length(nom)>255)or(length(aire)>255);
if name_too_long then abort;
{|kpse_find_file| will append the |".tfm"|, and avoid searching the disk
 before the font alias files as well.}
pack_file_name(nom,aire,"");
@z

% [30.564] Reading the tfm file.  As a special case, whenever we open a
% tfm file, we read its first byte into `tfm_temp' right away.  TeX
% looks at `fbyte' before calling `fget', so it ends up seeing every
% byte.  This is Pascal-like I/O.
@x [30.564] l.10991 - reading the tfm file, define fget & fbyte
@d fget==get(tfm_file)
@d fbyte==tfm_file^
@y
@d fget==tfm_temp:=getc(tfm_file)
@d fbyte==tfm_temp
@z

@x [30.570] l.11100 - MLTeX: fix for bug while loading font
  begin qw:=char_info(f)(d);
@y
  begin qw:=orig_char_info(f)(d);
@z

@x [30.573] l.11152 - MLTeX: fix for bug while loading font
  qw:=char_info(f)(#); {N.B.: not |qi(#)|}
@y
  qw:=orig_char_info(f)(#); {N.B.: not |qi(#)|}
@z

% [30.575] We only want `eof' on the TFM file to be true if we
% previously had EOF, not if we're at EOF now.  This is like `feof', and
% unlike our implementation of `eof' elsewhere.
@x [30.575] l.11197 - Reading the tfm file, replace eof() by feof().
if eof(tfm_file) then abort;
@y
if feof(tfm_file) then abort;
@z

@x [30.576] l.11216 - MLTeX: fix for bug while loading font
  begin qw:=char_info(f)(bchar); {N.B.: not |qi(bchar)|}
@y
  begin qw:=orig_char_info(f)(bchar); {N.B.: not |qi(bchar)|}
@z

@x [30.582] l.11312 - MLTeX: call |effective_char| in |new_character|
@p function new_character(@!f:internal_font_number;@!c:eight_bits):pointer;
label exit;
var p:pointer; {newly allocated node}
begin if font_bc[f]<=c then if font_ec[f]>=c then
  if char_exists(char_info(f)(qi(c))) then
@y

This allows a character node to be used if there is an equivalent
in the |char_sub_code| list.

@p function new_character(@!f:internal_font_number;@!c:eight_bits):pointer;
label exit;
var p:pointer; {newly allocated node}
@!ec:quarterword;  {effective character of |c|}
begin ec:=effective_char(false,f,qi(c));
if font_bc[f]<=qo(ec) then if font_ec[f]>=qo(ec) then
  if char_exists(orig_char_info(f)(ec)) then  {N.B.: not |char_info|}
@z

@x [32.592] l.11856 - font numbers can be >255 now.
@!c,@!f:quarterword; {character and font in current |char_node|}
@y
 {character and font in current |char_node|}
@!c:quarterword;
@!f:internal_font_number;
@z

@x [32.595] l.11896 - texarray
@!dvi_buf:array[dvi_index] of eight_bits; {buffer for \.{DVI} output}
@!half_buf:dvi_index; {half of |dvi_buf_size|}
@!dvi_limit:dvi_index; {end of the current half buffer}
@!dvi_ptr:dvi_index; {the next available buffer address}
@y
@!dvi_buf:^eight_bits; {buffer for \.{DVI} output}
@!half_buf:integer; {half of |dvi_buf_size|}
@!dvi_limit:integer; {end of the current half buffer}
@!dvi_ptr:integer; {the next available buffer address}
@z

@x [32.597] l.11922 - write_dvi done in C.
@p procedure write_dvi(@!a,@!b:dvi_index);
var k:dvi_index;
begin for k:=a to b do write(dvi_file,dvi_buf[k]);
end;
@y
In C, we use a macro to call |fwrite| or |write| directly, writing all
the bytes in one shot.  Much better even than writing four
bytes at a time.
@z

@x [32.598] l.11928 - check dvi file size
each time, we use the macro |dvi_out|.
@y
each time, we use the macro |dvi_out|.

The length of |dvi_file| should not exceed |@"7FFFFFFF|; we set |cur_s:=-2|
to prevent further \.{DVI} output causing infinite recursion.
@z

@x [32.598] l.11935 - dvi_swap: check dvi file size
begin if dvi_limit=dvi_buf_size then
@y
begin if dvi_ptr>(@"7FFFFFFF-dvi_offset) then
  begin cur_s:=-2;
  fatal_error("dvi length exceeds ""7FFFFFFF");
@.dvi length exceeds...@>
  end;
if dvi_limit=dvi_buf_size then
@z

@x [32.599] l.11949 - empty the last bytes: check dvi file size
if dvi_ptr>0 then write_dvi(0,dvi_ptr-1)
@y
if dvi_ptr>(@"7FFFFFFF-dvi_offset) then
  begin cur_s:=-2;
  fatal_error("dvi length exceeds ""7FFFFFFF");
@.dvi length exceeds...@>
  end;
if dvi_ptr>0 then write_dvi(0,dvi_ptr-1)
@z

@x [32.602] l.11980 - Allow for outputting more than 256 fonts.
begin dvi_out(fnt_def1);
dvi_out(f-font_base-1);@/
@y
begin if f<=256+font_base then
  begin dvi_out(fnt_def1);
  dvi_out(f-font_base-1);
  end
else begin dvi_out(fnt_def1+1);
  dvi_out((f-font_base-1) div @'400);
  dvi_out((f-font_base-1) mod @'400);
  end;
@z

@x [32.617] l.12297 - Use output_comment if the user set it. Assume it's short enough.
  old_setting:=selector; selector:=new_string;
@y
if output_comment then
  begin l:=strlen(output_comment); dvi_out(l);
  for s:=0 to l-1 do dvi_out(output_comment[s]);
  end
else begin {the default code is unchanged}
  old_setting:=selector; selector:=new_string;
@z

@x [32.617] l.12305 - Use output_comment if the user set it.
  end
@y
end;
  end
@z

@x [32.619] l.12330 - MLTeX: substitute character in |hlist_out|
procedure hlist_out; {output an |hlist_node| box}
label reswitch, move_past, fin_rule, next_p;
@y
procedure hlist_out; {output an |hlist_node| box}
label reswitch, move_past, fin_rule, next_p, continue, found;
@z

@x [32.620] l.12365 - MLTeX: replace virtual character in |hlist_out|
reaching a non-|char_node|. The program uses the fact that |set_char_0=0|.
@^inner loop@>
@y
reaching a non-|char_node|. The program uses the fact that |set_char_0=0|.

In ML\TeX{} this part looks for the existence of a substitution
definition for a character |c|, if |c| does not exist in the font,
and create appropriate \.{DVI} commands.  Former versions of ML\TeX{}
have spliced appropriate character, kern, and box nodes into the
horizontal list.
%
% 91/05/08 \charsubdefmax bug detected by Bernd Raichle
Because the user can change character substitutions or
\.{\\charsubdefmax} on the fly, we have to test a again
for valid substitutions.
%
% 93/10/29 \leaders bug detected by Eberhard Mattes
(Additional it is necessary to be careful---if leaders are used
the current hlist is normally traversed more than once!)
@^inner loop@>
@z

@x [32.620] l.12373 - MLTeX: substitute character during |shipout|
  if c>=qi(128) then dvi_out(set1);
  dvi_out(qo(c));@/
  cur_h:=cur_h+char_width(f)(char_info(f)(c));
@y
  if font_ec[f]>=qo(c) then if font_bc[f]<=qo(c) then
    if char_exists(orig_char_info(f)(c)) then  {N.B.: not |char_info|}
      begin if c>=qi(128) then dvi_out(set1);
      dvi_out(qo(c));@/
      cur_h:=cur_h+char_width(f)(orig_char_info(f)(c));
      goto continue;
      end;
  if mltex_enabled_p then
    @<Output a substitution, |goto continue| if not possible@>;
continue:
@z

@x [32.621] l.12388 - more >256 font output stuff.
else  begin dvi_out(fnt1); dvi_out(f-font_base-1);
  end;
@y
else if f<=256+font_base then
  begin dvi_out(fnt1); dvi_out(f-font_base-1);
  end
else begin dvi_out(fnt1+1);
  dvi_out((f-font_base-1) div @'400);
  dvi_out((f-font_base-1) mod @'400);
  end;
@z

% We output each portion of the page as we get to it, if we are using
% IPC, so that the previewer (TeXView) can display it immediately. [SPM]
@x [32.640] l.12740 - IPC
done:
@y
ifdef ('IPC')
if ipc_on>0 then
  begin if dvi_limit=half_buf then
    begin write_dvi(half_buf, dvi_buf_size-1);
    flush_dvi;
    dvi_gone:=dvi_gone+half_buf;
    end;
  if dvi_ptr>(@"7FFFFFFF-dvi_offset) then
    begin cur_s:=-2;
    fatal_error("dvi length exceeds ""7FFFFFFF");
@.dvi length exceeds...@>
    end;
  if dvi_ptr>0 then
    begin write_dvi(0, dvi_ptr-1);
    flush_dvi;
    dvi_offset:=dvi_offset+dvi_ptr; dvi_gone:=dvi_gone+dvi_ptr;
    end;
  dvi_ptr:=0; dvi_limit:=dvi_buf_size;
  ipc_page(dvi_gone);
  end;
endif ('IPC');
done:
@z

@x [32.642] l.12783 - check dvi file size
else  begin dvi_out(post); {beginning of the postamble}
@y
else if cur_s<>-2 then
  begin dvi_out(post); {beginning of the postamble}
@z

@x [32.642] l.12792 - Use dvi_offset instead of dvi_buf_size with IPC stuff.
  k:=4+((dvi_buf_size-dvi_ptr) mod 4); {the number of 223's}
@y
ifdef ('IPC')
  k:=7-((3+dvi_offset+dvi_ptr) mod 4); {the number of 223's}
endif ('IPC')
ifndef ('IPC')
  k:=4+((dvi_buf_size-dvi_ptr) mod 4); {the number of 223's}
endifn ('IPC')
@z

@x [32.642] l.12797 - use print_file_name
  print_nl("Output written on "); slow_print(output_file_name);
@y
  print_nl("Output written on "); print_file_name(0, output_file_name, 0);
@z

@x [32.642] l.12799 - i18n fix
  print(" ("); print_int(total_pages); print(" page");
  if total_pages<>1 then print_char("s");
@y
  print(" ("); print_int(total_pages);
  if total_pages<>1 then print(" pages")
  else print(" page");
@z

% The MLTeX changes never dealt with the problems of character
% substitutions in math mode.  With the new additions in v2.2,
% non-existing characters between |font_bc[f]| and |font_ec[f]|
% can be substituted => we have to avoid this in math mode
% (for compatibility reasons and to avoid other problems).
%
@x [35.708] l.13954 - MLTeX: avoid substitution in |var_delimiter|
if (qo(y)>=font_bc[g])and(qo(y)<=font_ec[g]) then
  begin continue: q:=char_info(g)(y);
@y
if (qo(y)>=font_bc[g])and(qo(y)<=font_ec[g]) then
  begin continue: q:=orig_char_info(g)(y);
@z

@x [36.722] l.14224 - MLTeX: avoid substitution in |fetch|
    cur_i:=char_info(cur_f)(cur_c)
@y
    cur_i:=orig_char_info(cur_f)(cur_c)
@z

@x [36.740] l.14537 - MLTeX: avoid substitution in |make_math_accent|
  i:=char_info(f)(y);
@y
  i:=orig_char_info(f)(y);
@z

@x [36.749] l.14689 - MLTeX: avoid substitution in |make_op|
    begin c:=rem_byte(cur_i); i:=char_info(cur_f)(c);
@y
    begin c:=rem_byte(cur_i); i:=orig_char_info(cur_f)(c);
@z

% disabled in original tex-src-special.ch
 @x [37.774] l.15291 - source specials
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
 @y
if (insert_src_special_every_cr and head<>tail) then insert_src_special;
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
 @z

% disabled in original tex-source-special.ch
 @x [37.799] l.15682 - source specials
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
 @y
if (insert_src_special_every_cr) then insert_src_special;
if every_cr<>null then begin_token_list(every_cr,every_cr_text);
 @z

@x [42.920] l.18111 - bigtrie: allow larger hyphenation tries.
Comparatively few different number sequences $n_0\ldots n_k$ actually occur,
since most of the |n|'s are generally zero. Therefore the number sequences
are encoded in such a way that |trie_op|$(z_k)$ is only one byte long.
If |trie_op(@t$z_k$@>)<>min_quarterword|, when $p_1\ldots p_k$ has matched
the letters in |hc[(l-k+1)..l@,]| of language |t|,
we perform all of the required operations
for this pattern by carrying out the following little program: Set
|v:=trie_op(@t$z_k$@>)|. Then set |v:=v+op_start[t]|,
|hyf[l-hyf_distance[v]]:=@tmax@>(hyf[l-hyf_distance[v]], hyf_num[v])|,
and |v:=hyf_next[v]|; repeat, if necessary, until |v=min_quarterword|.
@y
The theory that comparatively few different number sequences $n_0\ldots n_k$
actually occur, since most of the |n|'s are generally zero, seems to fail
at least for the large German hyphenation patterns.
Therefore the number sequences cannot any longer be encoded in such a way
that |trie_op|$(z_k)$ is only one byte long.
We have introduced a new constant |max_trie_op| for the maximum allowable
hyphenation operation code value; |max_trie_op| might be different for
\TeX\ and \.{INITEX} and must not exceed |max_halfword|.
An opcode will occupy a halfword if |max_trie_op| exceeds |max_quarterword|
or a quarterword otherwise.
@^system dependencies@>
If |trie_op(@t$z_k$@>)<>min_trie_op|, when $p_1\ldots p_k$ has matched
the letters in |hc[(l-k+1)..l@,]| of language |t|,
we perform all of the required operations
for this pattern by carrying out the following little program: Set
|v:=trie_op(@t$z_k$@>)|. Then set |v:=v+op_start[t]|,
|hyf[l-hyf_distance[v]]:=@tmax@>(hyf[l-hyf_distance[v]], hyf_num[v])|,
and |v:=hyf_next[v]|; repeat, if necessary, until |v=min_trie_op|.
@z

@x [42.920] l.18123 - bigtrie: allow larger hyphenation tries.
@!trie_pointer=0..trie_size; {an index into |trie|}
@y
@!trie_pointer=0..ssup_trie_size; {an index into |trie|}
@!trie_opcode=0..ssup_trie_opcode;  {a trie opcode}
@z

@x [42.921] l.18125 - bigtrie: allow larger hyphenation tries.
@ @d trie_link(#)==trie[#].rh {``downward'' link in a trie}
@d trie_char(#)==trie[#].b1 {character matched at this trie location}
@d trie_op(#)==trie[#].b0 {program for hyphenation at this trie location}
@y
@ For more than 255 trie op codes, the three fields |trie_link|, |trie_char|,
and |trie_op| will no longer fit into one memory word; thus using web2c
we define |trie| as three array instead of an array of records.
The variant will be implemented by reusing the opcode field later on with
another macro.

@d trie_link(#)==trie_trl[#] {``downward'' link in a trie}
@d trie_char(#)==trie_trc[#] {character matched at this trie location}
@d trie_op(#)==trie_tro[#] {program for hyphenation at this trie location}
@z

@x [42.921] l.18130 - bigtrie: allow larger hyphenation tries.
@!trie:array[trie_pointer] of two_halves; {|trie_link|, |trie_char|, |trie_op|}
@y
{We will dynamically allocate these arrays.}
@!trie_trl:^trie_pointer; {|trie_link|}
@!trie_tro:^trie_pointer; {|trie_op|}
@!trie_trc:^quarterword; {|trie_char|}
@z

@x [42.921] l.18133 - bigtrie: allow larger hyphenation tries.
@!hyf_next:array[1..trie_op_size] of quarterword; {continuation code}
@y
@!hyf_next:array[1..trie_op_size] of trie_opcode; {continuation code}
@z

@x [42.923] l.18154 - bigtrie: allow larger hyphenation tries.
    begin if trie_op(z)<>min_quarterword then
@y
    begin if trie_op(z)<>min_trie_op then
@z

@x [42.924] l.18167 - bigtrie: allow larger hyphenation tries.
until v=min_quarterword;
@y
until v=min_trie_op;
@z

%%%%%%%% dynamic hyph_size
@x [42.925] l.18181
different from $\alpha$, we can conclude that $\alpha$ is not in the table.
@y
different from $\alpha$, we can conclude that $\alpha$ is not in the table.
This is a clever scheme which saves the need for a hash link array.
However, it is difficult to increase the size of the hyphen exception
arrays. To make this easier, the ordered hash has been replaced by
a simple hash, using an additional array |hyph_link|. The value
|0| in |hyph_link[k]| means that there are no more entries corresponding
to the specific hash chain. When |hyph_link[k]>0|, the next entry in
the hash chain is |hyph_link[k]-1|. This value is used because the
arrays start at |0|.
@z

%%%%%%%% dynamic hyph_size
@x [42.925] l.18189
@!hyph_pointer=0..hyph_size; {an index into the ordered hash table}
@y
@!hyph_pointer=0..ssup_hyph_size; {index into hyphen exceptions hash table;
                     enlarging this requires changing (un)dump code}
@z

%%%%%%%% dynamic hyph_size
@x [42.926] l.18192
@!hyph_word:array[hyph_pointer] of str_number; {exception words}
@!hyph_list:array[hyph_pointer] of pointer; {lists of hyphen positions}
@!hyph_count:hyph_pointer; {the number of words in the exception dictionary}
@y
@!hyph_word: ^str_number; {exception words}
@!hyph_list: ^pointer; {lists of hyphen positions}
@!hyph_link: ^hyph_pointer; {link array for hyphen exceptions hash table}
@!hyph_count:integer; {the number of words in the exception dictionary}
@!hyph_next:integer; {next free slot in hyphen exceptions hash table}
@z

%%%%%%%% dynamic hyph_size
@x [42.928] l.18200
for z:=0 to hyph_size do
  begin hyph_word[z]:=0; hyph_list[z]:=null;
  end;
hyph_count:=0;
@y
for z:=0 to hyph_size do
  begin hyph_word[z]:=0; hyph_list[z]:=null; hyph_link[z]:=0;
  end;
hyph_count:=0;
hyph_next:=hyph_prime+1; if hyph_next>hyph_size then hyph_next:=hyph_prime;
@z

%%%%%%%% dynamic hyph_size
@x [42.930] l.18218
h:=hc[1]; incr(hn); hc[hn]:=cur_lang;
for j:=2 to hn do h:=(h+h+hc[j]) mod hyph_size;
loop@+  begin @<If the string |hyph_word[h]| is less than \(hc)|hc[1..hn]|,
    |goto not_found|; but if the two strings are equal,
    set |hyf| to the hyphen positions and |goto found|@>;
  if h>0 then decr(h)@+else h:=hyph_size;
  end;
not_found: decr(hn)
@y
h:=hc[1]; incr(hn); hc[hn]:=cur_lang;
for j:=2 to hn do h:=(h+h+hc[j]) mod hyph_prime;
loop@+  begin @<If the string |hyph_word[h]| is less than \(hc)|hc[1..hn]|,
    |goto not_found|; but if the two strings are equal,
    set |hyf| to the hyphen positions and |goto found|@>;
  h:=hyph_link[h]; if h=0 then goto not_found;
  decr(h);
  end;
not_found: decr(hn)
@z

@x [42.931] l.18227 - dynamic hyph_size
@ @<If the string |hyph_word[h]| is less than \(hc)...@>=
k:=hyph_word[h]; if k=0 then goto not_found;
if length(k)<hn then goto not_found;
@y
@ @<If the string |hyph_word[h]| is less than \(hc)...@>=
{This is now a simple hash list, not an ordered one, so
the module title is no longer descriptive.}
k:=hyph_word[h]; if k=0 then goto not_found;
@z

@x [42.931] l.18232 - dynamic hyph_size
  repeat if so(str_pool[u])<hc[j] then goto not_found;
  if so(str_pool[u])>hc[j] then goto done;
@y
  repeat
  if so(str_pool[u])<>hc[j] then goto done;
@z

%%%%%%%% dynamic hyph_size
@x [42.934] l.18273
@!s,@!t:str_number; {strings being compared or stored}
@y
@!s:str_number; {strings being compared or stored}
@z

%%%%%%%% dynamic hyph_size
@x [42.939] l.18329
  begin h:=(h+h+hc[j]) mod hyph_size;
@y
  begin h:=(h+h+hc[j]) mod hyph_prime;
@z

%%%%%%%% dynamic hyph_size
@x [42.940] l.18336
@ @<Insert the \(p)pair |(s,p)|...@>=
if hyph_count=hyph_size then overflow("exception dictionary",hyph_size);
@:TeX capacity exceeded exception dictionary}{\quad exception dictionary@>
incr(hyph_count);
while hyph_word[h]<>0 do
  begin @<If the string |hyph_word[h]| is less than \(or)or equal to
  |s|, interchange |(hyph_word[h],hyph_list[h])| with |(s,p)|@>;
  if h>0 then decr(h)@+else h:=hyph_size;
  end;
hyph_word[h]:=s; hyph_list[h]:=p
@y
@ @<Insert the \(p)pair |(s,p)|...@>=
  if hyph_next <= hyph_prime then
     while (hyph_next>0) and (hyph_word[hyph_next-1]>0) do decr(hyph_next);
if (hyph_count=hyph_size)or(hyph_next=0) then
   overflow("exception dictionary",hyph_size);
@:TeX capacity exceeded exception dictionary}{\quad exception dictionary@>
incr(hyph_count);
while hyph_word[h]<>0 do
  begin @<If the string |hyph_word[h]| is less than \(or)or equal to
  |s|, interchange |(hyph_word[h],hyph_list[h])| with |(s,p)|@>;
  if hyph_link[h]=0 then
  begin
    hyph_link[h]:=hyph_next;
    if hyph_next >= hyph_size then hyph_next:=hyph_prime;
    if hyph_next > hyph_prime then incr(hyph_next);
  end;
  h:=hyph_link[h]-1;
  end;

found: hyph_word[h]:=s; hyph_list[h]:=p
@z

@x [42.941] l.18347 - dynamic hyph_size
@ @<If the string |hyph_word[h]| is less than \(or)...@>=
k:=hyph_word[h];
if length(k)<length(s) then goto found;
if length(k)>length(s) then goto not_found;
@y
@ @<If the string |hyph_word[h]| is less than \(or)...@>=
{This is now a simple hash list, not an ordered one, so
the module title is no longer descriptive.}
k:=hyph_word[h];
if length(k)<>length(s) then goto not_found;
@z

@x [42.941] l.18352 - dynamic hyph_size
repeat if str_pool[u]<str_pool[v] then goto found;
if str_pool[u]>str_pool[v] then goto not_found;
@y
repeat if str_pool[u]<>str_pool[v] then goto not_found;
@z

@x [42.941] l.18356 - dynamic hyph_size
found:q:=hyph_list[h]; hyph_list[h]:=p; p:=q;@/
t:=hyph_word[h]; hyph_word[h]:=s; s:=t;
not_found:
@y
{repeat hyphenation exception; flushing old data}
flush_string; s:=hyph_word[h]; {avoid |slow_make_string|!}
decr(hyph_count);
{ We could also |flush_list(hyph_list[h]);|, but it interferes
  with \.{trip.log}. }
goto found;
not_found:
@z

@x [43.943] l.18387 - bigtrie: Larger tries, also in documentation parts.
|hyf_next[@t$v^\prime$@>]=min_quarterword|.
@y
|hyf_next[@t$v^\prime$@>]=min_trie_op|.
@z

@x [43.943] l.18391 - bigtrie: Larger tries, also in documentation parts.
$$\hbox{|@t$v^\prime$@>:=new_trie_op(0,1,min_quarterword)|,\qquad
@y
$$\hbox{|@t$v^\prime$@>:=new_trie_op(0,1,min_trie_op)|,\qquad
@z

@x [43.943] l.18401 - web2c can't parse negative lower bounds in arrays.  Sorry.
@!init @!trie_op_hash:array[-trie_op_size..trie_op_size] of 0..trie_op_size;
@y
@!init @!trie_op_hash:array[neg_trie_op_size..trie_op_size] of 0..trie_op_size;
@z

@x [43.943] l.18403 - bigtrie: Larger hyphenation tries.
@!trie_used:array[ASCII_code] of quarterword;
@y
@!trie_used:array[ASCII_code] of trie_opcode;
@z

@x [43.943] l.18407 - bigtrie: Larger hyphenation tries.
@!trie_op_val:array[1..trie_op_size] of quarterword;
@y
@!trie_op_val:array[1..trie_op_size] of trie_opcode;
@z

@x [43.943] l.18410 - Dynamic trie arrays
tini
@y
tini@;
@!max_op_used:trie_opcode; {largest opcode used for any language}
@!small_op:boolean; {flag used while dumping or undumping}
@z

@x [43.944] l.18413 - bigtrie: Larger tries, also in documentation parts.
|new_trie_op| could return |min_quarterword| (thereby simply ignoring
@y
|new_trie_op| could return |min_trie_op| (thereby simply ignoring
@z

@x [43.944] l.18420 - bigtrie: Larger hyphenation tries.
function new_trie_op(@!d,@!n:small_number;@!v:quarterword):quarterword;
label exit;
var h:-trie_op_size..trie_op_size; {trial hash location}
@!u:quarterword; {trial op code}
@y
function new_trie_op(@!d,@!n:small_number;@!v:trie_opcode):trie_opcode;
label exit;
var h:neg_trie_op_size..trie_op_size; {trial hash location}
@!u:trie_opcode; {trial op code}
@z

@x [43.944] l.18425 - Another casting problem, and use |neg_trie_op_size|.
begin h:=abs(n+313*d+361*v+1009*cur_lang) mod (trie_op_size+trie_op_size)
  - trie_op_size;
@y
begin h:=abs(n+313*d+361*v+1009*cur_lang) mod (trie_op_size-neg_trie_op_size)
  + neg_trie_op_size;
@z

@x [43.944] l.18432 - bigtrie: And larger tries again.
    if u=max_quarterword then
      overflow("pattern memory ops per language",
        max_quarterword-min_quarterword);
    incr(trie_op_ptr); incr(u); trie_used[cur_lang]:=u;
@y
    if u=max_trie_op then
      overflow("pattern memory ops per language",
      max_trie_op-min_trie_op);
    incr(trie_op_ptr); incr(u); trie_used[cur_lang]:=u;
    if u>max_op_used then max_op_used:=u;
@z

@x [43.945] l.18454 - bigtrie: And larger tries again.
op_start[0]:=-min_quarterword;
@y
op_start[0]:=-min_trie_op;
@z

@x [43.946] l.18471 - bigtrie: And larger tries again.
for k:=0 to 255 do trie_used[k]:=min_quarterword;
@y
for k:=0 to 255 do trie_used[k]:=min_trie_op;
@z

@x [43.946] l.18472 - Dynamic trie arrays.
trie_op_ptr:=0;
@y
max_op_used:=min_trie_op;
trie_op_ptr:=0;
@z

@x [43.947] l.18493 - Dynamically allocate arrays, and a casting problem.
@!init @!trie_c:packed array[trie_pointer] of packed_ASCII_code;
  {characters to match}
@t\hskip10pt@>@!trie_o:packed array[trie_pointer] of quarterword;
  {operations to perform}
@t\hskip10pt@>@!trie_l:packed array[trie_pointer] of trie_pointer;
  {left subtrie links}
@t\hskip10pt@>@!trie_r:packed array[trie_pointer] of trie_pointer;
  {right subtrie links}
@t\hskip10pt@>@!trie_ptr:trie_pointer; {the number of nodes in the trie}
@t\hskip10pt@>@!trie_hash:packed array[trie_pointer] of trie_pointer;
  {used to identify equivalent subtries}
tini
@y
@!init @!trie_c:^packed_ASCII_code;
  {characters to match}
@t\hskip10pt@>@!trie_o:^trie_opcode;
  {operations to perform}
@t\hskip10pt@>@!trie_l:^trie_pointer;
  {left subtrie links}
@t\hskip10pt@>@!trie_r:^trie_pointer;
  {right subtrie links}
@t\hskip10pt@>@!trie_ptr:trie_pointer; {the number of nodes in the trie}
@t\hskip10pt@>@!trie_hash:^trie_pointer;
  {used to identify equivalent subtries}
tini
@z

@x [43.950] l.18576 - Dynamically allocate & larger tries.
@d trie_back(#)==trie[#].lh {backward links in |trie| holes}
@y
@d trie_back(#)==trie_tro[#] {use the opcode field now for backward links}
@z

@x [43.950] l.18579 - Dynamically allocate & larger tries.
@!init @!trie_taken:packed array[1..trie_size] of boolean;
  {does a family start here?}
@t\hskip10pt@>@!trie_min:array[ASCII_code] of trie_pointer;
  {the first possible slot for each character}
@t\hskip10pt@>@!trie_max:trie_pointer; {largest location used in |trie|}
@t\hskip10pt@>@!trie_not_ready:boolean; {is the trie still in linked form?}
tini
@y
@!init @!trie_taken: ^boolean;
  {does a family start here?}
@t\hskip10pt@>@!trie_min:array[ASCII_code] of trie_pointer;
  {the first possible slot for each character}
@t\hskip10pt@>@!trie_max:trie_pointer; {largest location used in |trie|}
@t\hskip10pt@>@!trie_not_ready:boolean; {is the trie still in linked form?}
tini
@z

@x [43.951] l.18594 - Dynamically allocate.
trie_not_ready:=true; trie_root:=0; trie_c[0]:=si(0); trie_ptr:=0;
@y
trie_not_ready:=true;
@z

@x [43.958] l.18689 - bigtrie: Larger tries.
@<Move the data into |trie|@>=
h.rh:=0; h.b0:=min_quarterword; h.b1:=min_quarterword; {|trie_link:=0|,
  |trie_op:=min_quarterword|, |trie_char:=qi(0)|}
@y
@d clear_trie == {clear |trie[r]|}
  begin trie_link(r):=0;
  trie_op(r):=min_trie_op;
  trie_char(r):=min_quarterword; {|trie_char:=qi(0)|}
  end

@<Move the data into |trie|@>=
@z

@x [43.958] l.18693 - bigtrie: Larger tries.
  begin for r:=0 to 256 do trie[r]:=h;
@y
  begin for r:=0 to 256 do clear_trie;
@z

@x [43.958] l.18698 - bigtrie: Larger tries.
  repeat s:=trie_link(r); trie[r]:=h; r:=s;
@y
  repeat s:=trie_link(r); clear_trie; r:=s;
@z

@x [43.960] l.18732 - bigtrie: Larger tries.
@!v:quarterword; {trie op code}
@y
@!v:trie_opcode; {trie op code}
@z

@x [43.963] l.18804 - bigtrie: Larger tries.
if trie_o[q]<>min_quarterword then
@y
if trie_o[q]<>min_trie_op then
@z

@x [43.964] l.18817 - bigtrie: Larger tries.
trie_c[p]:=si(c); trie_o[p]:=min_quarterword;
@y
trie_c[p]:=si(c); trie_o[p]:=min_trie_op;
@z

@x [43.965] l.18823 - bigtrie: Larger tries.
l:=k; v:=min_quarterword;
@y
l:=k; v:=min_trie_op;
@z

@x [43.966] l.18841 - bigtrie: Larger tries.
@!h:two_halves; {template used to zero out |trie|'s holes}
@y
@z

%%
%% We can rewrite the original code after "main_loop_move+2" upto the
%% "tail_append(lig_stack)" in module 1036 as
%%
%
% main_loop_move+2:
% if font_bc[main_f]<=cur_chr then
%  if cur_chr<=font_ec[main_f] then
%    begin  main_i:=char_info(main_f)(cur_l);
%    if char_exists(main_i) goto main_loop_move+3;
%    end;
% char_warning(main_f,cur_chr); free_avail(lig_stack); goto big_switch;
% main_loop_move+3:
% tail_append(lig_stack) {|main_loop_lookahead| is next}
%
%%
%% We can use the rewritten code above to include additional MLTeX
%% specific parts in the future.  Additionally it can be used when
%% optimizing |main_control| to minimize the call of the function
%% |effective_char|.
%%
%
%@x [46.1030] l.19977 - MLTeX: substitution in |main_control|
%  main_loop_move,main_loop_move+1,main_loop_move+2,main_loop_move_lig,
%@y
%  main_loop_move,main_loop_move+1,main_loop_move+2,main_loop_move+3,
%  main_loop_move_lig,
%@z

@x [46.1034] l.20132 - source specials
@<Append character |cur_chr|...@>=
@y
@<Append character |cur_chr|...@>=
if ((head=tail) and (mode>0)) then begin
  if (insert_src_special_auto) then append_src_special;
end;
@z

@x [46.1036] l.20198 - MLTeX: substitution in |main_control|
main_loop_move+2:if(cur_chr<font_bc[main_f])or(cur_chr>font_ec[main_f]) then
@y
main_loop_move+2:
if(qo(effective_char(false,main_f,qi(cur_chr)))>font_ec[main_f])or
  (qo(effective_char(false,main_f,qi(cur_chr)))<font_bc[main_f]) then
@z

@x [46.1036] l.20201 - MLTeX: substitution in |main_control|
main_i:=char_info(main_f)(cur_l);
@y
main_i:=effective_char_info(main_f,cur_l);
@z

@x [46.1049] l.20440
print("' in "); print_mode(mode);
@y
print_in_mode(mode);
@z

% disabled in original tex-src-special.ch
 @x [47.1083] l.20966 - source specials
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
 @y
  if (insert_src_special_every_vbox) then insert_src_special;
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
 @z

% disabled in original tex-src-special.ch
 @x [47.1083] l.20969 - source specials
  if every_hbox<>null then begin_token_list(every_hbox,every_hbox_text);
 @y
  if (insert_src_special_every_hbox) then insert_src_special;
  if every_hbox<>null then begin_token_list(every_hbox,every_hbox_text);
 @z

@x [47.1091] l.21124 - source specials
if indented then
  begin tail:=new_null_box; link(head):=tail; width(tail):=par_indent;@+
  end;
@y
if indented then
  begin tail:=new_null_box; link(head):=tail; width(tail):=par_indent;
  if (insert_src_special_every_par) then insert_src_special;@+
  end;
@z

% disabled in original tex-src-special.ch, conflicts with etex.
 @x [47.1096] l.21121 - source specials
  else line_break(widow_penalty);
 @y
  else begin
    if (insert_src_special_every_parend) then insert_src_special;
    line_break(widow_penalty);
  end;
 @z

@x [48.1139] l.21722 - source specials
if every_math<>null then begin_token_list(every_math,every_math_text);
@y
if (insert_src_special_every_math) then insert_src_special;
if every_math<>null then begin_token_list(every_math,every_math_text);
@z

% disabled in original tex-src-special.ch
 @x [48.1145] l.21705 - source specials
if every_display<>null then begin_token_list(every_display,every_display_text);
 @y
if (insert_src_special_every_display) then append_src_special;
if every_display<>null then begin_token_list(every_display,every_display_text);
 @z

@x [48.1167] l.22114 - source specials
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
@y
  if (insert_src_special_every_vbox) then insert_src_special;
  if every_vbox<>null then begin_token_list(every_vbox,every_vbox_text);
@z

@x [49.1215] l.22793 - hash_extra
if (cur_cs=0)or(cur_cs>frozen_control_sequence) then
@y
if (cur_cs=0)or(cur_cs>eqtb_top)or
  ((cur_cs>frozen_control_sequence)and(cur_cs<=eqtb_size)) then
@z

@x [49.1222] l.22869 - MLTeX: \charsubdef primitive
@d toks_def_code=6 {|shorthand_def| for \.{\\toksdef}}
@y
@d toks_def_code=6 {|shorthand_def| for \.{\\toksdef}}
@d char_sub_def_code=7 {|shorthand_def| for \.{\\charsubdef}}
@z

@x [49.1222] l.22885 - MLTeX: \charsubdef primitive
@!@:toks_def_}{\.{\\toksdef} primitive@>
@y
@!@:toks_def_}{\.{\\toksdef} primitive@>
if mltex_p then
  begin
  primitive("charsubdef",shorthand_def,char_sub_def_code);@/
@!@:char_sub_def_}{\.{\\charsubdef} primitive@>
  end;
@z

@x [49.1223] l.22895 - MLTeX: \charsubdef primitive
  othercases print_esc("toksdef")
@y
  char_sub_def_code: print_esc("charsubdef");
  othercases print_esc("toksdef")
@z

@x [49.1224] l.22908 - MLTeX: \charsubdef primitive
shorthand_def: begin n:=cur_chr; get_r_token; p:=cur_cs; define(p,relax,256);
@y
shorthand_def: if cur_chr=char_sub_def_code then
 begin scan_char_num; p:=char_sub_code_base+cur_val; scan_optional_equals;
  scan_char_num; n:=cur_val; {accent character in substitution}
  scan_char_num;
  if (tracing_char_sub_def>0) then
    begin begin_diagnostic; print_nl("New character substitution: ");
    print_ASCII(p-char_sub_code_base); print(" = ");
    print_ASCII(n); print_char(" ");
    print_ASCII(cur_val); end_diagnostic(false);
    end;
  n:=n*256+cur_val;
  define(p,data,hi(n));
  if (p-char_sub_code_base)<char_sub_def_min then
    word_define(int_base+char_sub_def_min_code,p-char_sub_code_base);
  if (p-char_sub_code_base)>char_sub_def_max then
    word_define(int_base+char_sub_def_max_code,p-char_sub_code_base);
 end
else begin n:=cur_chr; get_r_token; p:=cur_cs; define(p,relax,256);
@z

@x [49.1252] l.23309 - INI = VIR, so have to do runtime test.
    begin @!init new_patterns; goto done;@;@+tini@/
@y
    begin @!Init new_patterns; goto done;@;@+Tini@/
@z

% undo Knuth's change because
%   a) the string is already replaced in |scan_file_name| and therefore
%   b) the wrong string will get flushed!!!
%
@x [49.1257] l.23354 - unused variable
@!flushable_string:str_number; {string not yet referenced}
@y
@z
@x [49.1260] l.23409 - new_font: string recycling -- already done
flushable_string:=str_ptr-1;
@y
@z

% If you don't want to remove code with the following two changes,
% please replace the former change by
%
% @x
% flushable_string:=str_ptr-1;
% @y
% if cur_name=str_ptr-1 then
%   flushable_string:=str_ptr-1
% else
%   flushable_string:=str_ptr;  {number of a non-existing}
% @z
%
% otherwise the wrong string will get removed by |flush_string|!!
%
@x [49.1260] l.23412 - new_font: string recycling -- already done
    begin if cur_name=flushable_string then
      begin flush_string; cur_name:=font_name[f];
      end;
    if s>0 then
@y
    begin if s>0 then
@z

@x [49.1265] l.23454 - if batchmode, mktex... scripts should be silent.
interaction:=cur_chr;
@y
interaction:=cur_chr;
if interaction = batch_mode
then kpse_make_tex_discard_errors := 1
else kpse_make_tex_discard_errors := 0;
@z

@x [49.1275] l.23519 - Same stuff as for \input, this time for \openin.
  if cur_ext="" then cur_ext:=".tex";
  pack_cur_name;
  if a_open_in(read_file[n]) then read_open[n]:=just_open;
@y
  pack_cur_name;
  tex_input_type:=0; {Tell |open_input| we are \.{\\openin}.}
  if kpse_in_name_ok(stringcast(name_of_file+1))
     and a_open_in(read_file[n], kpse_tex_format) then
    read_open[n]:=just_open;
@z

@x [50.1301] l.23760 - INI = VIR, so runtime test.
format_ident:=" (INITEX)";
@y
if ini_version then format_ident:=" (INITEX)";
@z

% Eliminate now-unused variable `w' in `store_fmt_file'.
% Add format_engine.
@x [50.1302] l.23768 - store_fmt_file
@!w: four_quarters; {four ASCII codes}
@y
@!format_engine: ^text_char;
@z

% MLTeX: dump |mltex_p| to fmt file
@x [50.1302] l.23772
@<Dump constants for consistency check@>;
@y
@<Dump constants for consistency check@>;
@<Dump ML\TeX-specific data@>;
@z

% Eliminate now-unused variable `w' in `load_fmt_file'.
% Add format_engine.
% Add dummies for undumping |xord|, |xchr|, and |xprn| into the void.
@x [50.1303] l.23800 - load_fmt_file
@!w: four_quarters; {four ASCII codes}
@y
@!format_engine: ^text_char;
@!dummy_xord: ASCII_code;
@!dummy_xchr: text_char;
@!dummy_xprn: ASCII_code;
@z

% MLTeX: undump |mltex_enabled_p| from fmt file
@x [50.1303] l.23801
begin @<Undump constants for consistency check@>;
@y
begin @<Undump constants for consistency check@>;
@<Undump ML\TeX-specific data@>;
@z

@x [50.1305] l.23829 - Do dumping and undumping of fmt files in C.
@d dump_wd(#)==begin fmt_file^:=#; put(fmt_file);@+end
@d dump_int(#)==begin fmt_file^.int:=#; put(fmt_file);@+end
@d dump_hh(#)==begin fmt_file^.hh:=#; put(fmt_file);@+end
@d dump_qqqq(#)==begin fmt_file^.qqqq:=#; put(fmt_file);@+end
@y
@z
@x [50.1306] l.23843
@d undump_wd(#)==begin get(fmt_file); #:=fmt_file^;@+end
@d undump_int(#)==begin get(fmt_file); #:=fmt_file^.int;@+end
@d undump_hh(#)==begin get(fmt_file); #:=fmt_file^.hh;@+end
@d undump_qqqq(#)==begin get(fmt_file); #:=fmt_file^.qqqq;@+end
@y
@z
@x [50.1306] l.23850 - debug format file
@d undump_size_end_end(#)==too_small(#)@+else undump_end_end
@y
@d format_debug_end(#)==
    write_ln (stderr, ' = ', #);
  end;
@d format_debug(#)==
  if debug_format_file then begin
    write (stderr, 'fmtdebug:', #);
    format_debug_end
@d undump_size_end_end(#)==
  too_small(#)@+else format_debug (#)(x); undump_end_end
@z

@x [50.1307] l.23859 - texarray
dump_int(@$);@/
@y
dump_int(@"57325458);  {Web2C \TeX's magic constant: "W2TX"}
{Align engine to 4 bytes with one or more trailing NUL}
x:=strlen(engine_name);
format_engine:=xmalloc_array(text_char,x+4);
strcpy(stringcast(format_engine), engine_name);
for k:=x to x+3 do format_engine[k]:=0;
x:=x+4-(x mod 4);
dump_int(x);dump_things(format_engine[0], x);
libc_free(format_engine);@/
dump_int(@$);@/
@<Dump |xord|, |xchr|, and |xprn|@>;
dump_int(max_halfword);@/
dump_int(hash_high);
@z

%%%%%%%% dynamic hyph_size
@x [50.1307] l.23864
dump_int(hyph_size)
@y
dump_int(hyph_prime)
@z

@x [50.1308] l.23873 - texarray
x:=fmt_file^.int;
if x<>@$ then goto bad_fmt; {check that strings are the same}
@y
@+Init
libc_free(font_info); libc_free(str_pool); libc_free(str_start);
libc_free(yhash); libc_free(zeqtb); libc_free(yzmem);
@+Tini
undump_int(x);
format_debug('format magic number')(x);
if x<>@"57325458 then goto bad_fmt; {not a format file}
undump_int(x);
format_debug('engine name size')(x);
if (x<0) or (x>256) then goto bad_fmt; {corrupted format file}
format_engine:=xmalloc_array(text_char, x);
undump_things(format_engine[0], x);
format_engine[x-1]:=0; {force string termination, just in case}
if strcmp(engine_name, stringcast(format_engine)) then
  begin wake_up_terminal;
  wterm_ln('---! ', stringcast(name_of_file+1), ' was written by ', format_engine);
  libc_free(format_engine);
  goto bad_fmt;
end;
libc_free(format_engine);
undump_int(x);
format_debug('string pool checksum')(x);
if x<>@$ then begin {check that strings are the same}
  wake_up_terminal;
  wterm_ln('---! ', stringcast(name_of_file+1),
           ' made by different executable version, strings are different');
  goto bad_fmt;
end;
@<Undump |xord|, |xchr|, and |xprn|@>;
undump_int(x);
if x<>max_halfword then goto bad_fmt; {check |max_halfword|}
undump_int(hash_high);
  if (hash_high<0)or(hash_high>sup_hash_extra) then goto bad_fmt;
  if hash_extra<hash_high then hash_extra:=hash_high;
  eqtb_top:=eqtb_size+hash_extra;
  if hash_extra=0 then hash_top:=undefined_control_sequence else
        hash_top:=eqtb_top;
  yhash:=xmalloc_array(two_halves,1+hash_top-hash_offset);
  hash:=yhash - hash_offset;
  next(hash_base):=0; text(hash_base):=0;
  for x:=hash_base+1 to hash_top do hash[x]:=hash[hash_base];
  zeqtb:=xmalloc_array (memory_word,eqtb_top+1);
  eqtb:=zeqtb;

  eq_type(undefined_control_sequence):=undefined_cs;
  equiv(undefined_control_sequence):=null;
  eq_level(undefined_control_sequence):=level_zero;
  for x:=eqtb_size+1 to eqtb_top do
    eqtb[x]:=eqtb[undefined_control_sequence];
@z

@x [50.1308] l.23875 - texarray
undump_int(x);
if x<>mem_bot then goto bad_fmt;
undump_int(x);
if x<>mem_top then goto bad_fmt;
@y
undump_int(x); format_debug ('mem_bot')(x);
if x<>mem_bot then goto bad_fmt;
undump_int(mem_top); format_debug ('mem_top')(mem_top);
if mem_bot+1100>mem_top then goto bad_fmt;


head:=contrib_head; tail:=contrib_head;
     page_tail:=page_head;  {page initialization}

mem_min := mem_bot - extra_mem_bot;
mem_max := mem_top + extra_mem_top;

yzmem:=xmalloc_array (memory_word, mem_max - mem_min + 1);
zmem := yzmem - mem_min;   {this pointer arithmetic fails with some compilers}
mem := zmem;
@z

%%%%%%%% dynamic hyph_size
@x [50.1308] l.23884
if x<>hyph_size then goto bad_fmt
@y
if x<>hyph_prime then goto bad_fmt
@z

% [1309] Make dumping/undumping more efficient by doing whole arrays at
% a time, via fread/fwrite in texmfmp.c.
@x [50.1309] l.23894 - Make dumping/undumping more efficient.
for k:=0 to str_ptr do dump_int(str_start[k]);
k:=0;
while k+4<pool_ptr do
  begin dump_four_ASCII; k:=k+4;
  end;
k:=pool_ptr-4; dump_four_ASCII;
@y
dump_things(str_start[0], str_ptr+1);
dump_things(str_pool[0], pool_ptr);
@z

@x [50.1310] l.23909 - Make dumping/undumping more efficient.
undump_size(0)(pool_size)('string pool size')(pool_ptr);
undump_size(0)(max_strings)('max strings')(str_ptr);
for k:=0 to str_ptr do undump(0)(pool_ptr)(str_start[k]);
k:=0;
while k+4<pool_ptr do
  begin undump_four_ASCII; k:=k+4;
  end;
k:=pool_ptr-4; undump_four_ASCII;
@y
undump_size(0)(sup_pool_size-pool_free)('string pool size')(pool_ptr);
if pool_size<pool_ptr+pool_free then
  pool_size:=pool_ptr+pool_free;
undump_size(0)(sup_max_strings-strings_free)('sup strings')(str_ptr);@/
if max_strings<str_ptr+strings_free then
  max_strings:=str_ptr+strings_free;
str_start:=xmalloc_array(pool_pointer, max_strings);
undump_checked_things(0, pool_ptr, str_start[0], str_ptr+1);@/
str_pool:=xmalloc_array(packed_ASCII_code, pool_size);
undump_things(str_pool[0], pool_ptr);
@z

@x [50.1311] l.23930 - Make dumping/undumping more efficient.
repeat for k:=p to q+1 do dump_wd(mem[k]);
@y
repeat dump_things(mem[p], q+2-p);
@z

@x [50.1311] l.23935 - Make dumping/undumping more efficient.
for k:=p to lo_mem_max do dump_wd(mem[k]);
@y
dump_things(mem[p], lo_mem_max+1-p);
@z

@x [50.1311] l.23938 - Make dumping/undumping more efficient.
for k:=hi_mem_min to mem_end do dump_wd(mem[k]);
@y
dump_things(mem[hi_mem_min], mem_end+1-hi_mem_min);
@z

@x [50.1312] l.23953 - Make dumping/undumping more efficient.
repeat for k:=p to q+1 do undump_wd(mem[k]);
@y
repeat undump_things(mem[p], q+2-p);
@z

@x [50.1312] l.23954 - Check that p did not become corrupt.
p:=q+node_size(q);
if (p>lo_mem_max)or((q>=rlink(q))and(rlink(q)<>rover)) then goto bad_fmt;
@y
{If the format file is messed up, that addition to |p| might cause it to
 become garbage. Report from Gregory James DUCK to Karl, 14 Sep 2023.
 Also changed in \MF. Fix from DRF, who explains: we test before doing the
 addition to avoid assuming silent wrap-around overflow, and also to to
 catch cases where |node_size| was, say, bogusly the equivalent of $-1$
 and thus |p+node_size| would still look valid.}
if (node_size(q)>lo_mem_max-q) or (rlink(q)>lo_mem_max)
   or ((q>=rlink(q))and(rlink(q)<>rover))
then goto bad_fmt;
p:=q+node_size(q);
@z

@x [50.1312] l.23958 - Make dumping/undumping more efficient.
for k:=p to lo_mem_max do undump_wd(mem[k]);
@y
undump_things(mem[p], lo_mem_max+1-p);
@z

@x [50.1312] l.23968 - Make dumping/undumping more efficient.
for k:=hi_mem_min to mem_end do undump_wd(mem[k]);
@y
undump_things (mem[hi_mem_min], mem_end+1-hi_mem_min);
@z

@x [50.1314] l.23979 - hash_extra, source specials
undump(hash_base)(frozen_control_sequence)(par_loc);
par_token:=cs_token_flag+par_loc;@/
undump(hash_base)(frozen_control_sequence)(write_loc);@/
@y
undump(hash_base)(hash_top)(par_loc);
par_token:=cs_token_flag+par_loc;@/
undump(hash_base)(hash_top)(write_loc);@/
@z

@x [50.1315] l.24005 - Make dumping/undumping more efficienteqtb
while k<l do
  begin dump_wd(eqtb[k]); incr(k);
  end;
@y
dump_things(eqtb[k], l-k);
@z

@x [50.1316] l.24024 - Make dumping/undumping more efficienteqtb
while k<l do
  begin dump_wd(eqtb[k]); incr(k);
  end;
@y
dump_things(eqtb[k], l-k);
@z

@x [50.1316] l.24027 - hash_extra
k:=j+1; dump_int(k-l);
until k>eqtb_size
@y
k:=j+1; dump_int(k-l);
until k>eqtb_size;
if hash_high>0 then dump_things(eqtb[eqtb_size+1],hash_high);
  {dump |hash_extra| part}
@z

@x [50.1317] l.24034 - Make dumping/undumping more efficienteqtb
for j:=k to k+x-1 do undump_wd(eqtb[j]);
@y
undump_things(eqtb[k], x);
@z

@x [50.1317] l.24040 - hash_extra
until k>eqtb_size
@y
until k>eqtb_size;
if hash_high>0 then undump_things(eqtb[eqtb_size+1],hash_high);
  {undump |hash_extra| part}
@z

@x [50.1318] l.24048 - hash_extra
dump_int(hash_used); cs_count:=frozen_control_sequence-1-hash_used;
@y
dump_int(hash_used); cs_count:=frozen_control_sequence-1-hash_used+hash_high;
@z

@x [50.1318] l.24052 - Make dumping/undumping more efficient, hash_extra
for p:=hash_used+1 to undefined_control_sequence-1 do dump_hh(hash[p]);
@y
dump_things(hash[hash_used+1], undefined_control_sequence-1-hash_used);
if hash_high>0 then dump_things(hash[eqtb_size+1], hash_high);
@z

@x [50.1319] l.24060 - Make dumping/undumping more efficient, hash_extra
for p:=hash_used+1 to undefined_control_sequence-1 do undump_hh(hash[p]);
@y
undump_things (hash[hash_used+1], undefined_control_sequence-1-hash_used);
if debug_format_file then begin
  print_csnames (hash_base, undefined_control_sequence - 1);
end;
if hash_high > 0 then begin
  undump_things (hash[eqtb_size+1], hash_high);
  if debug_format_file then begin
    print_csnames (eqtb_size + 1, hash_high - (eqtb_size + 1));
  end;
end;
@z

@x [50.1320] l.24065 - Make dumping/undumping more efficienttfm
for k:=0 to fmem_ptr-1 do dump_wd(font_info[k]);
dump_int(font_ptr);
for k:=null_font to font_ptr do
  @<Dump the array info for internal font number |k|@>;
@y
dump_things(font_info[0], fmem_ptr);
dump_int(font_ptr);
@<Dump the array info for internal font number |k|@>;
@z

@x [50.1320] l.24070 - i18n fix
print_int(font_ptr-font_base); print(" preloaded font");
if font_ptr<>font_base+1 then print_char("s")
@y
print_int(font_ptr-font_base);
if font_ptr<>font_base+1 then print(" preloaded fonts")
else print(" preloaded font")
@z

@x [50.1321] l.24074 - texarray
undump_size(7)(font_mem_size)('font mem size')(fmem_ptr);
for k:=0 to fmem_ptr-1 do undump_wd(font_info[k]);
undump_size(font_base)(font_max)('font max')(font_ptr);
for k:=null_font to font_ptr do
  @<Undump the array info for internal font number |k|@>
@y
undump_size(7)(sup_font_mem_size)('font mem size')(fmem_ptr);
if fmem_ptr>font_mem_size then font_mem_size:=fmem_ptr;
font_info:=xmalloc_array(fmemory_word, font_mem_size);
undump_things(font_info[0], fmem_ptr);@/
undump_size(font_base)(font_base+max_font_max)('font max')(font_ptr);
{This undumps all of the font info, despite the name.}
@<Undump the array info for internal font number |k|@>;
@z

% [50.1322] Dumping font_info.
% Knuth's code writes all the information relevant to a single font
% in the same section of the fmt file.  But it's a lot faster to
% write the arrays of information out, one whole array at a time.
% So that's the way we handle dumping and undumping font info.
@x [50.1322] l.24080 - Make dumping/undumping more efficienttfm
@ @<Dump the array info for internal font number |k|@>=
begin dump_qqqq(font_check[k]);
dump_int(font_size[k]);
dump_int(font_dsize[k]);
dump_int(font_params[k]);@/
dump_int(hyphen_char[k]);
dump_int(skew_char[k]);@/
dump_int(font_name[k]);
dump_int(font_area[k]);@/
dump_int(font_bc[k]);
dump_int(font_ec[k]);@/
dump_int(char_base[k]);
dump_int(width_base[k]);
dump_int(height_base[k]);@/
dump_int(depth_base[k]);
dump_int(italic_base[k]);
dump_int(lig_kern_base[k]);@/
dump_int(kern_base[k]);
dump_int(exten_base[k]);
dump_int(param_base[k]);@/
dump_int(font_glue[k]);@/
dump_int(bchar_label[k]);
dump_int(font_bchar[k]);
dump_int(font_false_bchar[k]);@/
print_nl("\font"); print_esc(font_id_text(k)); print_char("=");
print_file_name(font_name[k],font_area[k],"");
if font_size[k]<>font_dsize[k] then
  begin print(" at "); print_scaled(font_size[k]); print("pt");
  end;
end
@y
@ @<Dump the array info for internal font number |k|@>=
begin
dump_things(font_check[null_font], font_ptr+1-null_font);
dump_things(font_size[null_font], font_ptr+1-null_font);
dump_things(font_dsize[null_font], font_ptr+1-null_font);
dump_things(font_params[null_font], font_ptr+1-null_font);
dump_things(hyphen_char[null_font], font_ptr+1-null_font);
dump_things(skew_char[null_font], font_ptr+1-null_font);
dump_things(font_name[null_font], font_ptr+1-null_font);
dump_things(font_area[null_font], font_ptr+1-null_font);
dump_things(font_bc[null_font], font_ptr+1-null_font);
dump_things(font_ec[null_font], font_ptr+1-null_font);
dump_things(char_base[null_font], font_ptr+1-null_font);
dump_things(width_base[null_font], font_ptr+1-null_font);
dump_things(height_base[null_font], font_ptr+1-null_font);
dump_things(depth_base[null_font], font_ptr+1-null_font);
dump_things(italic_base[null_font], font_ptr+1-null_font);
dump_things(lig_kern_base[null_font], font_ptr+1-null_font);
dump_things(kern_base[null_font], font_ptr+1-null_font);
dump_things(exten_base[null_font], font_ptr+1-null_font);
dump_things(param_base[null_font], font_ptr+1-null_font);
dump_things(font_glue[null_font], font_ptr+1-null_font);
dump_things(bchar_label[null_font], font_ptr+1-null_font);
dump_things(font_bchar[null_font], font_ptr+1-null_font);
dump_things(font_false_bchar[null_font], font_ptr+1-null_font);
for k:=null_font to font_ptr do
  begin print_nl("\font"); print_esc(font_id_text(k)); print_char("=");
  print_file_name(font_name[k],font_area[k],"");
  if font_size[k]<>font_dsize[k] then
    begin print(" at "); print_scaled(font_size[k]); print("pt");
    end;
  end;
end
@z

@x [50.1323] l.24111 - Make dumping/undumping more efficienttfm
@ @<Undump the array info for internal font number |k|@>=
begin undump_qqqq(font_check[k]);@/
undump_int(font_size[k]);
undump_int(font_dsize[k]);
undump(min_halfword)(max_halfword)(font_params[k]);@/
undump_int(hyphen_char[k]);
undump_int(skew_char[k]);@/
undump(0)(str_ptr)(font_name[k]);
undump(0)(str_ptr)(font_area[k]);@/
undump(0)(255)(font_bc[k]);
undump(0)(255)(font_ec[k]);@/
undump_int(char_base[k]);
undump_int(width_base[k]);
undump_int(height_base[k]);@/
undump_int(depth_base[k]);
undump_int(italic_base[k]);
undump_int(lig_kern_base[k]);@/
undump_int(kern_base[k]);
undump_int(exten_base[k]);
undump_int(param_base[k]);@/
undump(min_halfword)(lo_mem_max)(font_glue[k]);@/
undump(0)(fmem_ptr-1)(bchar_label[k]);
undump(min_quarterword)(non_char)(font_bchar[k]);
undump(min_quarterword)(non_char)(font_false_bchar[k]);
end
@y
@ This module should now be named `Undump all the font arrays'.

@<Undump the array info for internal font number |k|@>=
begin {Allocate the font arrays}
font_check:=xmalloc_array(four_quarters, font_max);
font_size:=xmalloc_array(scaled, font_max);
font_dsize:=xmalloc_array(scaled, font_max);
font_params:=xmalloc_array(font_index, font_max);
font_name:=xmalloc_array(str_number, font_max);
font_area:=xmalloc_array(str_number, font_max);
font_bc:=xmalloc_array(eight_bits, font_max);
font_ec:=xmalloc_array(eight_bits, font_max);
font_glue:=xmalloc_array(halfword, font_max);
hyphen_char:=xmalloc_array(integer, font_max);
skew_char:=xmalloc_array(integer, font_max);
bchar_label:=xmalloc_array(font_index, font_max);
font_bchar:=xmalloc_array(nine_bits, font_max);
font_false_bchar:=xmalloc_array(nine_bits, font_max);
char_base:=xmalloc_array(integer, font_max);
width_base:=xmalloc_array(integer, font_max);
height_base:=xmalloc_array(integer, font_max);
depth_base:=xmalloc_array(integer, font_max);
italic_base:=xmalloc_array(integer, font_max);
lig_kern_base:=xmalloc_array(integer, font_max);
kern_base:=xmalloc_array(integer, font_max);
exten_base:=xmalloc_array(integer, font_max);
param_base:=xmalloc_array(integer, font_max);

undump_things(font_check[null_font], font_ptr+1-null_font);
undump_things(font_size[null_font], font_ptr+1-null_font);
undump_things(font_dsize[null_font], font_ptr+1-null_font);
undump_checked_things(min_halfword, max_halfword,
                      font_params[null_font], font_ptr+1-null_font);
undump_things(hyphen_char[null_font], font_ptr+1-null_font);
undump_things(skew_char[null_font], font_ptr+1-null_font);
undump_upper_check_things(str_ptr, font_name[null_font], font_ptr+1-null_font);
undump_upper_check_things(str_ptr, font_area[null_font], font_ptr+1-null_font);
{There's no point in checking these values against the range $[0,255]$,
 since the data type is |unsigned char|, and all values of that type are
 in that range by definition.}
undump_things(font_bc[null_font], font_ptr+1-null_font);
undump_things(font_ec[null_font], font_ptr+1-null_font);
undump_things(char_base[null_font], font_ptr+1-null_font);
undump_things(width_base[null_font], font_ptr+1-null_font);
undump_things(height_base[null_font], font_ptr+1-null_font);
undump_things(depth_base[null_font], font_ptr+1-null_font);
undump_things(italic_base[null_font], font_ptr+1-null_font);
undump_things(lig_kern_base[null_font], font_ptr+1-null_font);
undump_things(kern_base[null_font], font_ptr+1-null_font);
undump_things(exten_base[null_font], font_ptr+1-null_font);
undump_things(param_base[null_font], font_ptr+1-null_font);
undump_checked_things(min_halfword, lo_mem_max,
                     font_glue[null_font], font_ptr+1-null_font);
undump_checked_things(0, fmem_ptr-1,
                     bchar_label[null_font], font_ptr+1-null_font);
undump_checked_things(min_quarterword, non_char,
                     font_bchar[null_font], font_ptr+1-null_font);
undump_checked_things(min_quarterword, non_char,
                     font_false_bchar[null_font], font_ptr+1-null_font);
end
@z

%%%%%%%% dynamic hyph_size
@x [50.1324] l.24138
dump_int(hyph_count);
for k:=0 to hyph_size do if hyph_word[k]<>0 then
  begin dump_int(k); dump_int(hyph_word[k]); dump_int(hyph_list[k]);
  end;
@y
dump_int(hyph_count);
if hyph_next <= hyph_prime then hyph_next:=hyph_size;
dump_int(hyph_next);{minimum value of |hyphen_size| needed}
for k:=0 to hyph_size do if hyph_word[k]<>0 then
  begin dump_int(k+65536*hyph_link[k]);
        {assumes number of hyphen exceptions does not exceed 65535}
   dump_int(hyph_word[k]); dump_int(hyph_list[k]);
  end;
@z

@x [50.1324] l.24142 - i18n fix
print_ln; print_int(hyph_count); print(" hyphenation exception");
if hyph_count<>1 then print_char("s");
@y
print_ln; print_int(hyph_count);
if hyph_count<>1 then print(" hyphenation exceptions")
else print(" hyphenation exception");
@z

@x [50.1324] l.24146 - Make dumping/undumping more efficienttrie
for k:=0 to trie_max do dump_hh(trie[k]);
@y
dump_things(trie_trl[0], trie_max+1);
dump_things(trie_tro[0], trie_max+1);
dump_things(trie_trc[0], trie_max+1);
@z

@x [50.1324] l.24148 - Make dumping/undumping more efficienttrie
for k:=1 to trie_op_ptr do
  begin dump_int(hyf_distance[k]);
  dump_int(hyf_num[k]);
  dump_int(hyf_next[k]);
  end;
@y
dump_things(hyf_distance[1], trie_op_ptr);
dump_things(hyf_num[1], trie_op_ptr);
dump_things(hyf_next[1], trie_op_ptr);
@z

@x [50.1324] l.24155 - i18n fix
print(" has "); print_int(trie_op_ptr); print(" op");
if trie_op_ptr<>1 then print_char("s");
@y
print(" has "); print_int(trie_op_ptr);
if trie_op_ptr<>1 then print(" ops")
else print(" op");
@z

%%%%%%%% dynamic hyph_size
@x [50.1325] l.24167
undump(0)(hyph_size)(hyph_count);
for k:=1 to hyph_count do
  begin undump(0)(hyph_size)(j);
  undump(0)(str_ptr)(hyph_word[j]);
  undump(min_halfword)(max_halfword)(hyph_list[j]);
  end;
@y
undump_size(0)(hyph_size)('hyph_size')(hyph_count);
undump_size(hyph_prime)(hyph_size)('hyph_size')(hyph_next);
j:=0;
for k:=1 to hyph_count do
  begin undump_int(j); if j<0 then goto bad_fmt;
   if j>65535 then
   begin hyph_next:= j div 65536; j:=j - hyph_next * 65536; end
       else hyph_next:=0;
   if (j>=hyph_size)or(hyph_next>hyph_size) then goto bad_fmt;
   hyph_link[j]:=hyph_next;
  undump(0)(str_ptr)(hyph_word[j]);
  undump(min_halfword)(max_halfword)(hyph_list[j]);
  end;
  {|j| is now the largest occupied location in |hyph_word|}
  incr(j);
  if j<hyph_prime then j:=hyph_prime;
  hyph_next:=j;
  if hyph_next >= hyph_size then hyph_next:=hyph_prime else
  if hyph_next >= hyph_prime then incr(hyph_next);
@z

@x [50.1325] l.24174 - Make dumping/undumping more efficienttrie
for k:=0 to j do undump_hh(trie[k]);
@y
{These first three haven't been allocated yet unless we're \.{INITEX};
 we do that precisely so we don't allocate more space than necessary.}
if not trie_trl then trie_trl:=xmalloc_array(trie_pointer,j+1);
undump_things(trie_trl[0], j+1);
if not trie_tro then trie_tro:=xmalloc_array(trie_pointer,j+1);
undump_things(trie_tro[0], j+1);
if not trie_trc then trie_trc:=xmalloc_array(quarterword, j+1);
undump_things(trie_trc[0], j+1);
@z

@x [50.1325] l.24176 - Make dumping/undumping more efficienttrie
for k:=1 to j do
  begin undump(0)(63)(hyf_distance[k]); {a |small_number|}
  undump(0)(63)(hyf_num[k]);
  undump(min_quarterword)(max_quarterword)(hyf_next[k]);
  end;
@y
{I'm not sure we have such a strict limitation (64) on these values, so
 let's leave them unchecked.}
undump_things(hyf_distance[1], j);
undump_things(hyf_num[1], j);
undump_upper_check_things(max_trie_op, hyf_next[1], j);
@z

@x [50.1327] l.24197 - Allow command line to override dumped value.
undump(batch_mode)(error_stop_mode)(interaction);
@y
undump(batch_mode)(error_stop_mode)(interaction);
if interaction_option<>unspecified_mode then interaction:=interaction_option;
@z

@x [50.1327] l.24200 - Test for end-of-file already done by undump.
if (x<>69069)or eof(fmt_file) then goto bad_fmt
@y
if x<>69069 then goto bad_fmt
@z

@x [51.1332] l.24283 - make the main program a procedure, for eqtb hack.
@p begin @!{|start_here|}
@y
@d const_chk(#)==begin if # < inf@&# then # := inf@&# else
                         if # > sup@&# then # := sup@&# end

{|setup_bound_var| stuff duplicated in \.{mf.ch}.}
@d setup_bound_var(#)==bound_default:=#; setup_bound_var_end
@d setup_bound_var_end(#)==bound_name:=#; setup_bound_var_end_end
@d setup_bound_var_end_end(#)==
  setup_bound_variable(addressof(#), bound_name, bound_default)

@p procedure main_body;
begin @!{|start_here|}

{Bounds that may be set from the configuration file. We want the user to
 be able to specify the names with underscores, but \.{TANGLE} removes
 underscores, so we're stuck giving the names twice, once as a string,
 once as the identifier. How ugly.}
  setup_bound_var (0)('mem_bot')(mem_bot);
  setup_bound_var (250000)('main_memory')(main_memory);
    {|memory_word|s for |mem| in \.{INITEX}}
  setup_bound_var (0)('extra_mem_top')(extra_mem_top);
    {increase high mem in \.{VIRTEX}}
  setup_bound_var (0)('extra_mem_bot')(extra_mem_bot);
    {increase low mem in \.{VIRTEX}}
  setup_bound_var (200000)('pool_size')(pool_size);
  setup_bound_var (75000)('string_vacancies')(string_vacancies);
  setup_bound_var (5000)('pool_free')(pool_free); {min pool avail after fmt}
  setup_bound_var (15000)('max_strings')(max_strings);
  setup_bound_var (100)('strings_free')(strings_free);
  setup_bound_var (100000)('font_mem_size')(font_mem_size);
  setup_bound_var (500)('font_max')(font_max);
  setup_bound_var (20000)('trie_size')(trie_size);
    {if |ssup_trie_size| increases, recompile}
  setup_bound_var (659)('hyph_size')(hyph_size);
  setup_bound_var (3000)('buf_size')(buf_size);
  setup_bound_var (50)('nest_size')(nest_size);
  setup_bound_var (15)('max_in_open')(max_in_open);
  setup_bound_var (60)('param_size')(param_size);
  setup_bound_var (4000)('save_size')(save_size);
  setup_bound_var (300)('stack_size')(stack_size);
  setup_bound_var (16384)('dvi_buf_size')(dvi_buf_size);
  setup_bound_var (79)('error_line')(error_line);
  setup_bound_var (50)('half_error_line')(half_error_line);
  setup_bound_var (79)('max_print_line')(max_print_line);
  setup_bound_var (0)('hash_extra')(hash_extra);
  setup_bound_var (10000)('expand_depth')(expand_depth);

  const_chk (mem_bot);
  const_chk (main_memory);
@+Init
  extra_mem_top := 0;
  extra_mem_bot := 0;
@+Tini
  if extra_mem_bot>sup_main_memory then extra_mem_bot:=sup_main_memory;
  if extra_mem_top>sup_main_memory then extra_mem_top:=sup_main_memory;
  {|mem_top| is an index, |main_memory| a size}
  mem_top := mem_bot + main_memory -1;
  mem_min := mem_bot;
  mem_max := mem_top;

  {Check other constants against their sup and inf.}
  const_chk (trie_size);
  const_chk (hyph_size);
  const_chk (buf_size);
  const_chk (nest_size);
  const_chk (max_in_open);
  const_chk (param_size);
  const_chk (save_size);
  const_chk (stack_size);
  const_chk (dvi_buf_size);
  const_chk (pool_size);
  const_chk (string_vacancies);
  const_chk (pool_free);
  const_chk (max_strings);
  const_chk (strings_free);
  const_chk (font_mem_size);
  const_chk (font_max);
  const_chk (hash_extra);
  if error_line > ssup_error_line then error_line := ssup_error_line;

  {array memory allocation}
  buffer:=xmalloc_array (ASCII_code, buf_size);
  nest:=xmalloc_array (list_state_record, nest_size);
  save_stack:=xmalloc_array (memory_word, save_size);
  input_stack:=xmalloc_array (in_state_record, stack_size);
  input_file:=xmalloc_array (alpha_file, max_in_open);
  line_stack:=xmalloc_array (integer, max_in_open);
  source_filename_stack:=xmalloc_array (str_number, max_in_open);
  full_source_filename_stack:=xmalloc_array (str_number, max_in_open);
  param_stack:=xmalloc_array (halfword, param_size);
  dvi_buf:=xmalloc_array (eight_bits, dvi_buf_size);
  hyph_word :=xmalloc_array (str_number, hyph_size);
  hyph_list :=xmalloc_array (halfword, hyph_size);
  hyph_link :=xmalloc_array (hyph_pointer, hyph_size);
@+Init
  yzmem:=xmalloc_array (memory_word, mem_top - mem_bot + 1);
  zmem := yzmem - mem_bot;   {Some compilers require |mem_bot=0|}
  eqtb_top := eqtb_size+hash_extra;
  if hash_extra=0 then hash_top:=undefined_control_sequence else
        hash_top:=eqtb_top;
  yhash:=xmalloc_array (two_halves,1+hash_top-hash_offset);
  hash:=yhash - hash_offset;   {Some compilers require |hash_offset=0|}
  next(hash_base):=0; text(hash_base):=0;
  for hash_used:=hash_base+1 to hash_top do hash[hash_used]:=hash[hash_base];
  zeqtb:=xmalloc_array (memory_word, eqtb_top);
  eqtb:=zeqtb;

  str_start:=xmalloc_array (pool_pointer, max_strings);
  str_pool:=xmalloc_array (packed_ASCII_code, pool_size);
  font_info:=xmalloc_array (fmemory_word, font_mem_size);
@+Tini
@z

@x [51.1332] l.24295 - INI = VIR, so pool init needs runtime test
@!init if not get_strings_started then goto final_end;
init_prim; {call |primitive| for each primitive}
init_str_ptr:=str_ptr; init_pool_ptr:=pool_ptr; fix_date_and_time;
tini@/
@y
@!Init if not get_strings_started then goto final_end;
init_prim; {call |primitive| for each primitive}
init_str_ptr:=str_ptr; init_pool_ptr:=pool_ptr; fix_date_and_time;
Tini@/
@z

@x [51.1332] l.24305 - main
end_of_TEX: close_files_and_terminate;
final_end: ready_already:=0;
end.
@y
close_files_and_terminate;
final_end: do_final_end;
end {|main_body|};
@z

@x [51.1333] l.24334 - Print new line before termination; switch to editor if necessary.
    slow_print(log_name); print_char(".");
    end;
  end;
@y
    print_file_name(0, log_name, 0); print_char(".");
    end;
  end;
print_ln;
if (edit_name_start<>0) and (interaction>batch_mode) then
  call_edit(str_pool,edit_name_start,edit_name_length,edit_line);
@z

@x [51.1334] l.24355 - hash_extra
  wlog_ln(' ',cs_count:1,' multiletter control sequences out of ',
    hash_size:1);@/
@y
  wlog_ln(' ',cs_count:1,' multiletter control sequences out of ',
    hash_size:1, '+', hash_extra:1);@/
@z

@x [51.1335] l.24415 - Only do dump if ini.
  begin @!init for c:=top_mark_code to split_bot_mark_code do
@y
  begin @!Init for c:=top_mark_code to split_bot_mark_code do
@z

@x [51.1335] l.24418 - Only do dump if ini.
  store_fmt_file; return;@+tini@/
@y
  store_fmt_file; return;@+Tini@/
@z

@x [51.1337] l.24441 - Handle %&format in all cases.
if (format_ident=0)or(buffer[loc]="&") then
@y
if (format_ident=0)or(buffer[loc]="&")or dump_line then
@z

@x [51.1337] l.24447 - Dynamic arrays size.
  w_close(fmt_file);
@y
  w_close(fmt_file);
  eqtb:=zeqtb;
@z

%% [51.1337] l.24371 - MLTeX: add. MLTeX banner after loading fmt file
%%                     (MLTeX change: only "if mltex_enabled_p then ....;")
@x [51.1337] l.24452 - Allocate hyphenation tries, do char translation, MLTeX
fix_date_and_time;@/
@y
if mltex_enabled_p then
  begin wterm_ln('MLTeX v2.2 enabled');
  end;
fix_date_and_time;@/

@!init
if trie_not_ready then begin {initex without format loaded}
  trie_trl:=xmalloc_array (trie_pointer, trie_size);
  trie_tro:=xmalloc_array (trie_pointer, trie_size);
  trie_trc:=xmalloc_array (quarterword, trie_size);

  trie_c:=xmalloc_array (packed_ASCII_code, trie_size);
  trie_o:=xmalloc_array (trie_opcode, trie_size);
  trie_l:=xmalloc_array (trie_pointer, trie_size);
  trie_r:=xmalloc_array (trie_pointer, trie_size);
  trie_hash:=xmalloc_array (trie_pointer, trie_size);
  trie_taken:=xmalloc_array (boolean, trie_size);

  trie_root:=0; trie_c[0]:=si(0); trie_ptr:=0;

  {Allocate and initialize font arrays}
  font_check:=xmalloc_array(four_quarters, font_max);
  font_size:=xmalloc_array(scaled, font_max);
  font_dsize:=xmalloc_array(scaled, font_max);
  font_params:=xmalloc_array(font_index, font_max);
  font_name:=xmalloc_array(str_number, font_max);
  font_area:=xmalloc_array(str_number, font_max);
  font_bc:=xmalloc_array(eight_bits, font_max);
  font_ec:=xmalloc_array(eight_bits, font_max);
  font_glue:=xmalloc_array(halfword, font_max);
  hyphen_char:=xmalloc_array(integer, font_max);
  skew_char:=xmalloc_array(integer, font_max);
  bchar_label:=xmalloc_array(font_index, font_max);
  font_bchar:=xmalloc_array(nine_bits, font_max);
  font_false_bchar:=xmalloc_array(nine_bits, font_max);
  char_base:=xmalloc_array(integer, font_max);
  width_base:=xmalloc_array(integer, font_max);
  height_base:=xmalloc_array(integer, font_max);
  depth_base:=xmalloc_array(integer, font_max);
  italic_base:=xmalloc_array(integer, font_max);
  lig_kern_base:=xmalloc_array(integer, font_max);
  kern_base:=xmalloc_array(integer, font_max);
  exten_base:=xmalloc_array(integer, font_max);
  param_base:=xmalloc_array(integer, font_max);

  font_ptr:=null_font; fmem_ptr:=7;
  font_name[null_font]:="nullfont"; font_area[null_font]:="";
  hyphen_char[null_font]:="-"; skew_char[null_font]:=-1;
  bchar_label[null_font]:=non_address;
  font_bchar[null_font]:=non_char; font_false_bchar[null_font]:=non_char;
  font_bc[null_font]:=1; font_ec[null_font]:=0;
  font_size[null_font]:=0; font_dsize[null_font]:=0;
  char_base[null_font]:=0; width_base[null_font]:=0;
  height_base[null_font]:=0; depth_base[null_font]:=0;
  italic_base[null_font]:=0; lig_kern_base[null_font]:=0;
  kern_base[null_font]:=0; exten_base[null_font]:=0;
  font_glue[null_font]:=null; font_params[null_font]:=7;
  param_base[null_font]:=-1;
  for font_k:=0 to 6 do font_info[font_k].sc:=0;
  end;
  tini@/

  font_used:=xmalloc_array (boolean, font_max);
  for font_k:=font_base to font_max do font_used[font_k]:=false;
@z

% [52.1338] Core-dump in debugging mode on 0 input.  Under Unix, it's
% not possible to portably switch into the debugger while a program is
% running.  The best approximation is to do a core dump, then run the
% debugger on it later.
@x [52.1338] l.24493 - Core-dump in debugging mode on 0 input.
    begin goto breakpoint;@/ {go to every declared label at least once}
    breakpoint: m:=0; @{'BREAKPOINT'@}@/
    end
@y
    dump_core {do something to cause a core dump}
@z

@x [52.1339] l.24511 - debugprint tfm info
5: print_word(font_info[n]);
@y
5: begin print_scaled(font_info[n].sc); print_char(" ");@/
  print_int(font_info[n].qqqq.b0); print_char(":");@/
  print_int(font_info[n].qqqq.b1); print_char(":");@/
  print_int(font_info[n].qqqq.b2); print_char(":");@/
  print_int(font_info[n].qqqq.b3);
  end;
@z

@x [53.1344] l.24624 - source specials
primitive("special",extension,special_node);@/
@y
primitive("special",extension,special_node);@/
text(frozen_special):="special"; eqtb[frozen_special]:=eqtb[cur_val];@/
@z

@x [53.1348] l.24657 - (do_extension) Remove unused variables
var i,@!j,@!k:integer; {all-purpose integers}
@!p,@!q,@!r:pointer; {all-purpose pointers}
@y
var k:integer; {all-purpose integers}
@!p:pointer; {all-purpose pointers}
@z

% [53.1350] (new_write_whatsit) Allow 18 as a \write stream. We never
% refer to an actual file, though, so we don't need to change the
% write_file or write_open arrays. We provide for disabling this at
% runtime, for paranoids.
@x [53.1350] l.24691 - system: Allow 18 as a \write stream.
  else if cur_val>15 then cur_val:=16;
@y
  else if (cur_val>15) and (cur_val <> 18) then cur_val:=16;
@z

@x [53.1370] l.24852 - \write18{foo}
begin @<Expand macros in the token list
@y
@!d:integer; {number of characters in incomplete current string}
@!clobbered:boolean; {system string is ok?}
@!runsystem_ret:integer; {return value from |runsystem|}
begin @<Expand macros in the token list
@z

@x [53.1370] l.24855 - system: (write_out) \write18{foo} => system(foo).
if write_open[j] then selector:=j
@y
if j=18 then selector := new_string
else if write_open[j] then selector:=j
@z

% Then call system(3) on that string.
@x [53.1370] l.24861 - system: (write_out) \write18{foo} => system(foo).
flush_list(def_ref); selector:=old_setting;
@y
flush_list(def_ref);
if j=18 then
  begin if (tracing_online<=0) then
    selector:=log_only  {Show what we're doing in the log file.}
  else selector:=term_and_log;  {Show what we're doing.}
  {If the log file isn't open yet, we can only send output to the terminal.
   Calling |open_log_file| from here seems to result in bad data in the log.}
  if not log_opened then selector:=term_only;
  print_nl("runsystem(");
  for d:=0 to cur_length-1 do
    begin {|print| gives up if passed |str_ptr|, so do it by hand.}
    print(so(str_pool[str_start[str_ptr]+d])); {N.B.: not |print_char|}
    end;
  print(")...");
  if shellenabledp then begin
    str_room(1); append_char(0); {Append a null byte to the expansion.}
    clobbered:=false;
    for d:=0 to cur_length-1 do {Convert to external character set.}
      begin
        str_pool[str_start[str_ptr]+d]:=xchr[str_pool[str_start[str_ptr]+d]];
        if (str_pool[str_start[str_ptr]+d]=null_code)
           and (d<cur_length-1) then clobbered:=true;
        {minimal checking: NUL not allowed in argument string of |system|()}
      end;
    if clobbered then print("clobbered")
    else begin {We have the command.  See if we're allowed to execute it,
         and report in the log.  We don't check the actual exit status of
         the command, or do anything with the output.}
      runsystem_ret := runsystem(conststringcast(addressof(
                                              str_pool[str_start[str_ptr]])));
      if runsystem_ret = -1 then print("quotation error in system command")
      else if runsystem_ret = 0 then print("disabled (restricted)")
      else if runsystem_ret = 1 then print("executed")
      else if runsystem_ret = 2 then print("executed safely (allowed)")
    end;
  end else begin
    print("disabled"); {|shellenabledp| false}
  end;
  print_char("."); print_nl(""); print_ln;
  pool_ptr:=str_start[str_ptr];  {erase the string}
end;
selector:=old_setting;
@z

@x [53.1373] l.24902 - Need new local.
procedure out_what(@!p:pointer);
var j:small_number; {write stream number}
@y
procedure out_what(@!p:pointer);
var j:small_number; {write stream number}
    @!old_setting:0..max_selector;
@z

@x [53.1374] l.24923
  else  begin if write_open[j] then a_close(write_file[j]);
    if subtype(p)=close_node then write_open[j]:=false
@y
  else  begin if write_open[j] then begin a_close(write_file[j]);
                                          write_open[j]:=false; end;
    if subtype(p)=close_node then do_nothing {already closed}
@z

@x [53.1374] l.24930 - Disallow certain \openout filenames, and log results.
      while not a_open_out(write_file[j]) do
        prompt_file_name("output file name",".tex");
      write_open[j]:=true;
@y
      while not kpse_out_name_ok(stringcast(name_of_file+1))
            or not a_open_out(write_file[j]) do
        prompt_file_name("output file name",".tex");
      write_open[j]:=true;
      {If on first line of input, log file is not ready yet, so don't log.}
      if log_opened and texmf_yesno('log_openout') then begin
        old_setting:=selector;
        if (tracing_online<=0) then
          selector:=log_only  {Show what we're doing in the log file.}
        else selector:=term_and_log;  {Show what we're doing.}
        print_nl("\openout");
        print_int(j);
        print(" = `");
        print_file_name(cur_name,cur_area,cur_ext);
        print("'."); print_nl(""); print_ln;
        selector:=old_setting;
      end;
@z

@x [54.1379] l.24985 - Add editor-switch variables to globals.
@* \[54] System-dependent changes.
This section should be replaced, if necessary, by any special
modifications of the program
that are necessary to make \TeX\ work at a particular installation.
It is usually best to design your change file so that all changes to
previous sections preserve the section numbering; then everybody's version
will be consistent with the published program. More extensive changes,
which introduce new sections, can be inserted here; then only the index
itself will get a new section number.
@^system dependencies@>

@y
@* \[54/web2c] System-dependent changes for Web2c.
Here are extra variables for Web2c.  (This numbering of the
system-dependent section allows easy integration of Web2c and e-\TeX, etc.)
@^system dependencies@>

@<Glob...@>=
@!edit_name_start: pool_pointer; {where the filename to switch to starts}
@!edit_name_length,@!edit_line: integer; {what line to start editing at}
@!ipc_on: cinttype; {level of IPC action, 0 for none [default]}
@!stop_at_space: boolean; {whether |more_name| returns false for space}

@ The |edit_name_start| will be set to point into |str_pool| somewhere after
its beginning if \TeX\ is supposed to switch to an editor on exit.

Initialize the |stop_at_space| variable for filename parsing.

Initialize the |halting_on_error_p| variable to avoid infloop with
\.{--halt-on-error}.

@<Set init...@>=
edit_name_start:=0;
stop_at_space:=true;
halting_on_error_p:=false;

@ These are used when we regenerate the representation of the first 256
strings.

@<Global...@> =
@!save_str_ptr: str_number;
@!save_pool_ptr: pool_pointer;
@!shellenabledp: cinttype;
@!restrictedshell: cinttype;
@!output_comment: ^char;
@!k,l: 0..255; {used by `Make the first 256 strings', etc.}

@ When debugging a macro package, it can be useful to see the exact
control sequence names in the format file.  For example, if ten new
csnames appear, it's nice to know what they are, to help pinpoint where
they came from.  (This isn't a truly ``basic'' printing procedure, but
that's a convenient module in which to put it.)

@<Basic printing procedures@> =
procedure print_csnames (hstart:integer; hfinish:integer);
var c,h:integer;
begin
  write_ln(stderr, 'fmtdebug:csnames from ', hstart, ' to ', hfinish, ':');
  for h := hstart to hfinish do begin
    if text(h) > 0 then begin {if have anything at this position}
      for c := str_start[text(h)] to str_start[text(h) + 1] - 1
      do begin
        put_byte(str_pool[c], stderr); {print the characters}
      end;
      write_ln(stderr, '|');
    end;
  end;
end;

@ Are we printing extra info as we read the format file?

@<Glob...@> =
@!debug_format_file: boolean;


@ A helper for printing file:line:error style messages.  Look for a
filename in |full_source_filename_stack|, and if we fail to find
one fall back on the non-file:line:error style.

@<Basic print...@>=
procedure print_file_line;
var level: 0..max_in_open;
begin
  level:=in_open;
  while (level>0) and (full_source_filename_stack[level]=0) do
    decr(level);
  if level=0 then
    print_nl("! ")
  else begin
    print_nl (""); print (full_source_filename_stack[level]); print (":");
    if level=in_open then print_int (line)
    else print_int (line_stack[level+1]);
    print (": ");
  end;
end;

@ To be able to determine whether \.{\\write18} is enabled from within
\TeX\ we also implement \.{\\eof18}.  We sort of cheat by having an
additional route |scan_four_bit_int_or_18| which is the same as
|scan_four_bit_int| except it also accepts the value 18.

@<Declare procedures that scan restricted classes of integers@>=
procedure scan_four_bit_int_or_18;
begin scan_int;
if (cur_val<0)or((cur_val>15)and(cur_val<>18)) then
  begin print_err("Bad number");
@.Bad number@>
  help2("Since I expected to read a number between 0 and 15,")@/
    ("I changed this one to zero."); int_error(cur_val); cur_val:=0;
  end;
end;

@ Dumping the |xord|, |xchr|, and |xprn| arrays.  We dump these always
in the format, so a TCX file loaded during format creation can set a
default for users of the format.

@<Dump |xord|, |xchr|, and |xprn|@>=
dump_things(xord[0], 256);
dump_things(xchr[0], 256);
dump_things(xprn[0], 256);

@ Undumping the |xord|, |xchr|, and |xprn| arrays.  This code is more
complicated, because we want to ensure that a TCX file specified on
the command line will override whatever is in the format.  Since the
tcx file has already been loaded, that implies throwing away the data
in the format.  Also, if no |translate_filename| is given, but
|eight_bit_p| is set we have to make all characters printable.

@<Undump |xord|, |xchr|, and |xprn|@>=
if translate_filename then begin
  for k:=0 to 255 do undump_things(dummy_xord, 1);
  for k:=0 to 255 do undump_things(dummy_xchr, 1);
  for k:=0 to 255 do undump_things(dummy_xprn, 1);
  end
else begin
  undump_things(xord[0], 256);
  undump_things(xchr[0], 256);
  undump_things(xprn[0], 256);
  if eight_bit_p then
    for k:=0 to 255 do
      xprn[k]:=1;
end;


@* \[54/web2c-string] The string recycling routines.
\TeX{} uses 2 upto 4 {\it new\/} strings when scanning a filename in an
\.{\\input}, \.{\\openin}, or \.{\\openout} operation.  These strings are
normally lost because the reference to them are not saved after finishing
the operation.  |search_string| searches through the string pool for the
given string and returns either 0 or the found string number.

@<Declare additional routines for string recycling@>=
function search_string(@!search:str_number):str_number;
label found;
var result: str_number;
@!s: str_number; {running index}
@!len: integer; {length of searched string}
begin result:=0; len:=length(search);
if len=0 then  {trivial case}
  begin result:=""; goto found;
  end
else  begin s:=search-1;  {start search with newest string below |s|; |search>1|!}
  while s>255 do  {first 256 strings depend on implementation!!}
    begin if length(s)=len then
      if str_eq_str(s,search) then
        begin result:=s; goto found;
        end;
    decr(s);
    end;
  end;
found:search_string:=result;
end;

@ The following routine is a variant of |make_string|.  It searches
the whole string pool for a string equal to the string currently built
and returns a found string.  Otherwise a new string is created and
returned.  Be cautious, you can not apply |flush_string| to a replaced
string!

@<Declare additional routines for string recycling@>=
function slow_make_string : str_number;
label exit;
var s: str_number; {result of |search_string|}
@!t: str_number; {new string}
begin t:=make_string; s:=search_string(t);
if s>0 then
  begin flush_string; slow_make_string:=s; return;
  end;
slow_make_string:=t;
exit:end;


@* \[54/web2c] More changes for Web2c.
% Related to [25.366] expansion depth check
Sometimes, recursive calls to the |expand| routine may
cause exhaustion of the run-time calling stack, resulting in
forced execution stops by the operating system. To diminish the chance
of this happening, a counter is used to keep track of the recursion
depth, in conjunction with a constant called |expand_depth|.

This does not catch all possible infinite recursion loops, just the ones
that exhaust the application calling stack. The actual maximum value of
|expand_depth| is outside of our control, but the initial setting of
|10000| should be enough to prevent problems.
@^system dependencies@>

@<Global...@>=
expand_depth_count:integer;

@ @<Set init...@>=
expand_depth_count:=0;

@ % Related to [29.526] expansion depth check
When |scan_file_name| starts it looks for a |left_brace|
(skipping \.{\\relax}es, as other \.{\\toks}-like primitives).
If a |left_brace| is found, then the procedure scans a file
name contained in a balanced token list, expanding tokens as
it goes. When the scanner finds the balanced token list, it
is converted into a string and fed character-by-character to
|more_name| to do its job the same as in the ``normal'' file
name scanning.

@p procedure scan_file_name_braced;
var
  @!save_scanner_status: small_number; {|scanner_status| upon entry}
  @!save_def_ref: pointer; {|def_ref| upon entry, important if inside `\.{\\message}}
  @!save_cur_cs: pointer;
  @!s: str_number; {temp string}
  @!p: pointer; {temp pointer}
  @!i: integer; {loop tally}
  @!save_stop_at_space: boolean; {this should be in tex.ch}
  @!dummy: boolean;
    {Initializing}
begin save_scanner_status := scanner_status; {|scan_toks| sets |scanner_status| to |absorbing|}
  save_def_ref := def_ref; {|scan_toks| uses |def_ref| to point to the token list just read}
  save_cur_cs := cur_cs; {we set |cur_cs| back a few tokens to use in runaway errors}
    {Scanning a token list}
  cur_cs := warning_index; {for possible runaway error}
  {mimick |call_func| from pdfTeX}
  if scan_toks(false, true) <> 0 then do_nothing; {actually do the scanning}
  {|s := tokens_to_string(def_ref);|}
  old_setting := selector; selector:=new_string;
  show_token_list(link(def_ref),null,pool_size-pool_ptr);
  selector := old_setting;
  s := make_string;
  {turns the token list read in a string to input}
    {Restoring some variables}
  delete_token_ref(def_ref); {remove the token list from memory}
  def_ref := save_def_ref; {and restore |def_ref|}
  cur_cs := save_cur_cs; {restore |cur_cs|}
  scanner_status := save_scanner_status; {restore |scanner_status|}
    {Passing the read string to the input machinery}
  save_stop_at_space := stop_at_space; {save |stop_at_space|}
  stop_at_space := false; {set |stop_at_space| to false to allow spaces in file names}
  begin_name;
  for i:=str_start[s] to str_start[s+1]-1 do
    dummy := more_name(str_pool[i]); {add each read character to the current file name}
  stop_at_space := save_stop_at_space; {restore |stop_at_space|}
end;


@* \[54/ML\TeX] System-dependent changes for ML\TeX.
@^system dependencies@>
The boolean variable |mltex_p| is set by web2c according to the given
command line option (or an entry in the configuration file) before any
\TeX{} function is called.

@<Global...@> =
@!mltex_p: boolean;

@ The boolean variable |mltex_enabled_p| is used to enable ML\TeX's
character substitution.  It is initialized to |false|.  When loading
a \.{FMT} it is set to the value of the boolean |mltex_p| saved in
the \.{FMT} file.  Additionally it is set to the value of |mltex_p|
in Ini\TeX.

@<Glob...@>=
@!mltex_enabled_p:boolean;  {enable character substitution}


@ @<Set init...@>=
mltex_enabled_p:=false;


@ The function |effective_char| computes the effective character with
respect to font information.  The effective character is either the
base character part of a character substitution definition, if the
character does not exist in the font or the character itself.

Inside |effective_char| we can not use |char_info| because the macro
|char_info| uses |effective_char| calling this function a second time
with the same arguments.

If neither the character |c| exists in font |f| nor a character
substitution for |c| was defined, you can not use the function value
as a character offset in |char_info| because it will access an
undefined or invalid |font_info| entry!  Therefore inside |char_info|
and in other places, |effective_char|'s boolean parameter |err_p| is
set to |true| to issue a warning and return the incorrect
replacement, but always existing character |font_bc[f]|.
@^inner loop@>

@<Declare additional functions for ML\TeX@>=
function effective_char(@!err_p:boolean;
                        @!f:internal_font_number;@!c:quarterword):integer;
label found;
var base_c: integer; {or |eightbits|: replacement base character}
@!result: integer; {or |quarterword|}
begin result:=c;  {return |c| unless it does not exist in the font}
if not mltex_enabled_p then goto found;
if font_ec[f]>=qo(c) then if font_bc[f]<=qo(c) then
  if char_exists(orig_char_info(f)(c)) then  {N.B.: not |char_info|(f)(c)}
    goto found;
if qo(c)>=char_sub_def_min then if qo(c)<=char_sub_def_max then
  if char_list_exists(qo(c)) then
    begin base_c:=char_list_char(qo(c));
    result:=qi(base_c);  {return |base_c|}
    if not err_p then goto found;
    if font_ec[f]>=base_c then if font_bc[f]<=base_c then
      if char_exists(orig_char_info(f)(qi(base_c))) then goto found;
    end;
if err_p then  {print error and return existing character?}
  begin begin_diagnostic;
  print_nl("Missing character: There is no "); print("substitution for ");
@.Missing character@>
  print_ASCII(qo(c)); print(" in font ");
  slow_print(font_name[f]); print_char("!"); end_diagnostic(false);
  result:=qi(font_bc[f]); {N.B.: not non-existing character |c|!}
  end;
found: effective_char:=result;
end;


@ The function |effective_char_info| is equivalent to |char_info|,
except it will return |null_character| if neither the character |c|
exists in font |f| nor is there a substitution definition for |c|.
(For these cases |char_info| using |effective_char| will access an
undefined or invalid |font_info| entry.  See the documentation of
|effective_char| for more information.)
@^inner loop@>

@<Declare additional functions for ML\TeX@>=
function effective_char_info(@!f:internal_font_number;
                             @!c:quarterword):four_quarters;
label exit;
var ci:four_quarters; {character information bytes for |c|}
@!base_c:integer; {or |eightbits|: replacement base character}
begin if not mltex_enabled_p then
  begin effective_char_info:=orig_char_info(f)(c); return;
  end;
if font_ec[f]>=qo(c) then if font_bc[f]<=qo(c) then
  begin ci:=orig_char_info(f)(c);  {N.B.: not |char_info|(f)(c)}
  if char_exists(ci) then
    begin effective_char_info:=ci; return;
    end;
  end;
if qo(c)>=char_sub_def_min then if qo(c)<=char_sub_def_max then
  if char_list_exists(qo(c)) then
    begin {|effective_char_info:=char_info(f)(qi(char_list_char(qo(c))));|}
    base_c:=char_list_char(qo(c));
    if font_ec[f]>=base_c then if font_bc[f]<=base_c then
      begin ci:=orig_char_info(f)(qi(base_c));  {N.B.: not |char_info|(f)(c)}
      if char_exists(ci) then
        begin effective_char_info:=ci; return;
        end;
      end;
    end;
effective_char_info:=null_character;
exit:end;


@ This code is called for a virtual character |c| in |hlist_out|
during |ship_out|.  It tries to built a character substitution
construct for |c| generating appropriate \.{DVI} code using the
character substitution definition for this character.  If a valid
character substitution exists \.{DVI} code is created as if
|make_accent| was used.  In all other cases the status of the
substitution for this character has been changed between the creation
of the character node in the hlist and the output of the page---the
created \.{DVI} code will be correct but the visual result will be
undefined.

Former ML\TeX\ versions have replaced the character node by a
sequence of character, box, and accent kern nodes splicing them into
the original horizontal list.  This version does not do this to avoid
a)~a memory overflow at this processing stage, b)~additional code to
add a pointer to the previous node needed for the replacement, and
c)~to avoid wrong code resulting in anomalies because of the use
within a \.{\\leaders} box.

@<Output a substitution, |goto continue| if not possible@>=
  begin
  @<Get substitution information, check it, goto |found|
  if all is ok, otherwise goto |continue|@>;
found: @<Print character substitution tracing log@>;
  @<Rebuild character using substitution information@>;
  end


@ The global variables for the code to substitute a virtual character
can be declared as local.  Nonetheless we declare them as global to
avoid stack overflows because |hlist_out| can be called recursively.

@<Glob...@>=
@!accent_c,@!base_c,@!replace_c:integer;
@!ia_c,@!ib_c:four_quarters; {accent and base character information}
@!base_slant,@!accent_slant:real; {amount of slant}
@!base_x_height:scaled; {accent is designed for characters of this height}
@!base_width,@!base_height:scaled; {height and width for base character}
@!accent_width,@!accent_height:scaled; {height and width for accent}
@!delta:scaled; {amount of right shift}


@ Get the character substitution information in |char_sub_code| for
the character |c|.  The current code checks that the substitution
exists and is valid and all substitution characters exist in the
font, so we can {\it not\/} substitute a character used in a
substitution.  This simplifies the code because we have not to check
for cycles in all character substitution definitions.

@<Get substitution information, check it...@>=
  if qo(c)>=char_sub_def_min then if qo(c)<=char_sub_def_max then
    if char_list_exists(qo(c)) then
      begin  base_c:=char_list_char(qo(c));
      accent_c:=char_list_accent(qo(c));
      if (font_ec[f]>=base_c) then if (font_bc[f]<=base_c) then
        if (font_ec[f]>=accent_c) then if (font_bc[f]<=accent_c) then
          begin ia_c:=char_info(f)(qi(accent_c));
          ib_c:=char_info(f)(qi(base_c));
          if char_exists(ib_c) then
            if char_exists(ia_c) then goto found;
          end;
      begin_diagnostic;
      print_nl("Missing character: Incomplete substitution ");
@.Missing character@>
      print_ASCII(qo(c)); print(" = "); print_ASCII(accent_c);
      print(" "); print_ASCII(base_c); print(" in font ");
      slow_print(font_name[f]); print_char("!"); end_diagnostic(false);
      goto continue;
      end;
  begin_diagnostic;
  print_nl("Missing character: There is no "); print("substitution for ");
@.Missing character@>
  print_ASCII(qo(c)); print(" in font ");
  slow_print(font_name[f]); print_char("!"); end_diagnostic(false);
  goto continue


@ For |tracinglostchars>99| the substitution is shown in the log file.

@<Print character substitution tracing log@>=
 if tracing_lost_chars>99 then
   begin begin_diagnostic;
   print_nl("Using character substitution: ");
   print_ASCII(qo(c)); print(" = ");
   print_ASCII(accent_c); print(" "); print_ASCII(base_c);
   print(" in font "); slow_print(font_name[f]); print_char(".");
   end_diagnostic(false);
   end


@ This outputs the accent and the base character given in the
substitution.  It uses code virtually identical to the |make_accent|
procedure, but without the node creation steps.

Additionally if the accent character has to be shifted vertically it
does {\it not\/} create the same code.  The original routine in
|make_accent| and former versions of ML\TeX{} creates a box node
resulting in |push| and |pop| operations, whereas this code simply
produces vertical positioning operations.  This can influence the
pixel rounding algorithm in some \.{DVI} drivers---and therefore will
probably be changed in one of the next ML\TeX{} versions.

@<Rebuild character using substitution information@>=
  base_x_height:=x_height(f);
  base_slant:=slant(f)/float_constant(65536);
@^real division@>
  accent_slant:=base_slant; {slant of accent character font}
  base_width:=char_width(f)(ib_c);
  base_height:=char_height(f)(height_depth(ib_c));
  accent_width:=char_width(f)(ia_c);
  accent_height:=char_height(f)(height_depth(ia_c));
  @/{compute necessary horizontal shift (don't forget slant)}@/
  delta:=round((base_width-accent_width)/float_constant(2)+
            base_height*base_slant-base_x_height*accent_slant);
@^real multiplication@>
@^real addition@>
  dvi_h:=cur_h;  {update |dvi_h|, similar to the last statement in module 620}
  @/{1. For centering/horizontal shifting insert a kern node.}@/
  cur_h:=cur_h+delta; synch_h;
  @/{2. Then insert the accent character possibly shifted up or down.}@/
  if ((base_height<>base_x_height) and (accent_height>0)) then
    begin {the accent must be shifted up or down}
    cur_v:=base_line+(base_x_height-base_height); synch_v;
    if accent_c>=128 then dvi_out(set1);
    dvi_out(accent_c);@/
    cur_v:=base_line;
    end
  else begin synch_v;
    if accent_c>=128 then dvi_out(set1);
    dvi_out(accent_c);@/
    end;
  cur_h:=cur_h+accent_width; dvi_h:=cur_h;
  @/{3. For centering/horizontal shifting insert another kern node.}@/
  cur_h:=cur_h+(-accent_width-delta);
  @/{4. Output the base character.}@/
  synch_h; synch_v;
  if base_c>=128 then dvi_out(set1);
  dvi_out(base_c);@/
  cur_h:=cur_h+base_width;
  dvi_h:=cur_h {update of |dvi_h| is unnecessary, will be set in module 620}

@ Dumping ML\TeX-related material.  This is just the flag in the
format that tells us whether ML\TeX{} is enabled.

@<Dump ML\TeX-specific data@>=
dump_int(@"4D4C5458);  {ML\TeX's magic constant: "MLTX"}
if mltex_p then dump_int(1)
else dump_int(0);

@ Undump ML\TeX-related material, which is just a flag in the format
that tells us whether ML\TeX{} is enabled.

@<Undump ML\TeX-specific data@>=
undump_int(x);   {check magic constant of ML\TeX}
if x<>@"4D4C5458 then goto bad_fmt;
undump_int(x);   {undump |mltex_p| flag into |mltex_enabled_p|}
if x=1 then mltex_enabled_p:=true
else if x<>0 then goto bad_fmt;
@z

@x [55.1380] l.24996 - extra routines
@* \[55] Index.
@y

@* \[54] System-dependent changes.

@<Declare action procedures for use by |main_control|@>=

procedure insert_src_special;
var toklist, p, q : pointer;
begin
  if (source_filename_stack[in_open] > 0 and is_new_source (source_filename_stack[in_open]
, line)) then begin
    toklist := get_avail;
    p := toklist;
    info(p) := cs_token_flag+frozen_special;
    link(p) := get_avail; p := link(p);
    info(p) := left_brace_token+"{";
    q := str_toks (make_src_special (source_filename_stack[in_open], line));
    link(p) := link(temp_head);
    p := q;
    link(p) := get_avail; p := link(p);
    info(p) := right_brace_token+"}";
    ins_list (toklist);
    remember_source_info (source_filename_stack[in_open], line);
  end;
end;

procedure append_src_special;
var q : pointer;
begin
  if (source_filename_stack[in_open] > 0 and is_new_source (source_filename_stack[in_open]
, line)) then begin
    new_whatsit (special_node, write_node_size);
    write_stream(tail) := 0;
    def_ref := get_avail;
    token_ref_count(def_ref) := null;
    q := str_toks (make_src_special (source_filename_stack[in_open], line));
    link(def_ref) := link(temp_head);
    write_tokens(tail) := def_ref;
    remember_source_info (source_filename_stack[in_open], line);
  end;
end;

@ This function used to be in pdftex, but is useful in tex too.

@p function get_nullstr: str_number;
begin
    get_nullstr := "";
end;


@* \[55] Index.
@z