% Change file for GNU Pascal and Linux
% (by Don Knuth, 2000; see ../tex-sparc for the prehistory)
% (I'm no longer keeping the "efficiency" changes; just enuf for TRIP test)
%
% Use this file as is to make an INITEX.  To get triptex, use the
% shell script ``ini_to_trip'' and re-TANGLE.

% History:
% 2000.04.30 first sketch --- untested --- see FIXTHIS for parts not done yet

% NOTE: the module numbers in this change file refer to Volume B.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [0] WEAVE: only print changes
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
\def\botofcontents{\vskip 0pt plus 1fil minus 1.5in}
@y
\def\botofcontents{\vskip 0pt plus 1fil minus 1.5in}
\let\maybe=\iffalse
\def\title{\TeX82 changes for GNU Pascal}
\def\glob{13}\def\gglob{20, 26} % these are defined in module 1
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.2] banner line
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d banner=='This is TeX, Version 3.14159' {printed when \TeX\ starts}
@y
@d banner=='This is TeX, Version 3.14159 for Linux' {printed when \TeX\ starts}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.4] program header
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
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.
@^system dependencies@>

@d mtype==t@&y@&p@&e {this is a \.{WEB} coding trick:}
@y
@d mtype==t@&y@&p@&e {this is a \.{WEB} coding trick:}
@d standard_input==i@&n@&p@&u@&t {and another}
@z
@x
program TEX; {all file names are defined dynamically}
label @<Labels in the outer block@>@/
const @<Constants in the outer block@>@/
mtype @<Types in the outer block@>@/
var @<Global variables@>@/
@y
program TEX(standard_input,output); {other file names are defined dynamically}
label @<Labels in the outer block@>@/
const @<Constants in the outer block@>@/
mtype @!UNIX_filename = packed array[1..file_name_size] of char;@/
@<Types in the outer block@>@/
var @<Global variables@>@/
@#
@\@=#include "ext.h"@>@\ {declarations for external C procedures}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.7] debug..gubed, stat..tats
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d debug==@{ {change this to `$\\{debug}\equiv\null$' when debugging}
@d gubed==@t@>@} {change this to `$\\{gubed}\equiv\null$' when debugging}
@y
@d debug==@{ {the trip test will use debugging}
@d gubed==@t@>@}
@z
@x
@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==
@d tats==
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.8] init..tini
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d init== {change this to `$\\{init}\equiv\.{@@\{}$' in the production version}
@d tini== {change this to `$\\{tini}\equiv\.{@@\}}$' in the production version}
@y
@d init==
@d tini==
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.10] othercases, feature of ISO Extended Pascal
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d othercases == others: {default for cases not listed explicitly}
@y
@d othercases == otherwise {default for cases not listed explicitly}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.11] compile-time constants
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@!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
@!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=-32767; {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=5000; {maximum number of characters simultaneously present in
  current lines of open files and in control sequences between
  \.{\\csname} and \.{\\endcsname}; must not exceed |max_halfword|}
@!error_line=79; {width of context lines on terminal error messages}
@!half_error_line=50; {width of first lines of contexts in terminal
  error messages; should be between 30 and |error_line-15|}
@!max_print_line=79; {width of longest text lines output; should be at least 60}
@!stack_size=200; {maximum number of simultaneous input sources}
@!max_in_open=15; {maximum number of input files and error insertions that
  can be going on simultaneously}
@!font_max=127; {maximum internal font number; must not exceed |max_quarterword|
  and must be at most |font_base+256|}
@!font_mem_size=40000; {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=60000; {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=1024; {file names shouldn't be longer than this}
@!pool_name='tex.pool';
  {string of length |file_name_size|; the string pool name}
@.TeXformats@>
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1.12] sensitive compile-time constants
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@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 mem_bot=-32767 {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=4000 {maximum number of control sequences; it should be at most
  about |(mem_max-mem_min)/10|}
@d hash_prime=3443 {a prime number equal to about 85\pct! of |hash_size|}
@d hyph_size=307 {another prime; the number of \.{\\hyphenation} exceptions}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [2.23] allow any character that we can input to get in
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
for i:=0 to @'37 do xchr[i]:=' ';
for i:=@'177 to @'377 do xchr[i]:=' ';
@y
for i:=0 to @'37 do xchr[i]:=chr(i);
for i:=@'177 to @'377 do xchr[i]:=chr(i);
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.25] file types
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@!eight_bits=0..255; {unsigned one-byte quantity}
@!alpha_file=packed file of text_char; {files that contain textual data}
@y
@!eight_bits=ByteCard; {unsigned one-byte quantity}
@!alpha_file=t@&e@&x@&t; {files that contain textual data}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.26] add real_name_of_file array
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
is crucial for our purposes. We shall assume that |name_of_file| is a variable
of an appropriate type such that the \PASCAL\ run-time system being used to
implement \TeX\ can open a file whose external name is specified by
|name_of_file|.
@^system dependencies@>

@<Glob...@>=
@!name_of_file:packed array[1..file_name_size] of char;@;@/
  {on some systems this may be a \&{record} variable}
@y
is crucial for our purposes. We shall assume that |name_of_file| is a variable
of an appropriate type such that the \PASCAL\ run-time system being used to
implement \TeX\ can open a file whose external name is specified by
|name_of_file|.
The Linux version uses search paths to look for files to open.
We use |real_name_of_file| to hold the |name_of_file| with a directory
name from the path in front of it.
@^system dependencies@>

@<Glob...@>=
@!name_of_file,@!real_name_of_file:external UNIX_filename;
@;@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.27] file opening
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ 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
@ An external C procedure, |test_access| is used to check whether or not the
open will work.  It is declared in the ``ext.h'' include file, and it returns
|true| or |false|. The |name_of_file| global holds the file name whose access
is to be tested.
The first parameter for |test_access| is the access mode,
one of |read_access_mode| or |write_access_mode|.

We also implement path searching in |test_access|:  its second parameter is
one of the ``file path'' constants defined below.  If |name_of_file|
doesn't start with |'/'| then |test_access| tries prepending pathnames
from the appropriate path list until success or the end of path list
is reached.
On return, |real_name_of_file| contains the original name with the path
that succeeded (if any) prepended.  It is the name used in the various
open procedures.

Note that |a_open_in| has been redefined to take an additional argument,
which should be one of the ``file path'' specifiers.
Since |b_open_in| is only used for \.{TFM} files, and
|w_open_in| is only used for format files, we don't need a path specifying
argument for them.
Path searching is not done for output files.

@d read_access_mode=4  {``read'' mode for |test_access|}
@d write_access_mode=2 {``write'' mode for |test_access|}

@d no_file_path=0    {no path searching should be done}
@d input_file_path=1 {path specifier for \.{\\input} files}
@d read_file_path=2  {path specifier for \.{\\read} files}
@d font_file_path=3  {path specifier for \.{TFM} files}
@d format_file_path=4 {path specifier for format files}
@d pool_file_path=5  {path specifier for the pool file}

@p function a_open_in(var f:alpha_file;@!path_specifier:integer):boolean;
  {open a text file for input}
var @!ok:boolean;
begin
if test_access(read_access_mode,path_specifier) then
    begin reset(f,real_name_of_file); ok:=true@+end
else
    ok:=false;
a_open_in:=ok;
end;
@#
function a_open_out(var f:alpha_file):boolean;
  {open a text file for output}
var @!ok:boolean;
begin
if test_access(write_access_mode,no_file_path) then
    begin rewrite(f,real_name_of_file); ok:=true @+end
else ok:=false;
a_open_out:=ok;
end;
@#
function b_open_in(var f:byte_file):boolean;
  {open a binary file for input}
var @!ok:boolean;
begin
if test_access(read_access_mode,font_file_path) then
    begin reset(f,real_name_of_file); ok:=true @+end
else ok:=false;
b_open_in:=ok;
end;
@#
function b_open_out(var f:byte_file):boolean;
  {open a binary file for output}
var @!ok:boolean;
begin
if test_access(write_access_mode,no_file_path) then
    begin rewrite(f,real_name_of_file); ok:=true @+end
else ok:=false;
b_open_out:=ok;
end;
@#
function w_open_in(var f:word_file):boolean;
  {open a word file for input}
var @!ok:boolean;
begin
if test_access(read_access_mode,format_file_path) then
    begin reset(f,real_name_of_file); ok:=true @+end
else ok:=false;
w_open_in:=ok;
end;
@#
function w_open_out(var f:word_file):boolean;
  {open a word file for output}
var @!ok:boolean;
begin
if test_access(write_access_mode,no_file_path) then
    begin rewrite(f,name_of_file); ok:=true @+end
else ok:=false;
w_open_out:=ok;
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.28] file closing
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
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
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.

With the pc library, files will be automatically closed when the program stops
and when one reopens them.
There is, however, the problem of opening a file and writing it, and then
wanting to read it again, but from a different file variable.
For this purpose we use external procedures |close_a|, |close_b|, and
|close_w|.

@p procedure a_close(var f:alpha_file); {close a text file}
begin close_a(f);
end;
@#
procedure b_close(var f:byte_file); {close a binary file}
begin close_b(f);
end;
@#
procedure w_close(var f:word_file); {close a word file}
begin close_w(f);
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.32] term_in/out are input,output
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ The user's terminal acts essentially like other files of text, except
that it is used both for input and for output. When the terminal is
considered an input file, the file variable is called |term_in|, and when it
is considered an output file the file variable is |term_out|.
@^system dependencies@>

@<Glob...@>=
@!term_in:alpha_file; {the terminal as an input file}
@!term_out:alpha_file; {the terminal as an output file}
@y
@ The user's terminal acts essentially like other files of text, except
that it is used both for input and for output. When the terminal is
considered an input file, the file is called |term_in|, and when it
is considered an output file the file is |term_out|.
For Berkeley {\mc UNIX} we use |standard_input| and |output| for these
files, as were declared in the program header.   The former name
|standard_input| was defined using a .{WEB} trick so that `input' is
produced in the Pascal file.

@d term_in==standard_input {the terminal as an input file}
@d term_out==output {the terminal as an output file}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.33] don't need to open terminal files
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ Here is how to open the terminal files
in \ph. The `\.{/I}' switch suppresses the first |get|.
@^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---do nothing.

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

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3.34] flushing output
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
these operations can be specified in \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}
@d wake_up_terminal == do_nothing {cancel the user's cancellation of output}
@y
these operations can be specified with Berkeley {\mc UNIX}:
@^system dependencies@>

@d update_terminal == flush_stdout
@d clear_terminal == {nothing necessary on UNIX}
@d wake_up_terminal == {nothing necessary on UNIX}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [4.38] string data
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@!packed_ASCII_code = 0..255; {elements of |str_pool| array}
@y
@!packed_ASCII_code = ByteCard; {elements of |str_pool| array}
@z
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [4.51] a_open_in of pool file needs path specifier
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
if a_open_in(pool_file) then
@y
if a_open_in(pool_file,pool_file_path) then
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [4.51,52,53] make TEX.POOL lowercase in messages
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
else  bad_pool('! I can''t read TEX.POOL.')
@y
else  bad_pool('! I can''t read tex.pool.')
@z
@x
begin if eof(pool_file) then bad_pool('! TEX.POOL has no check sum.');
@y
begin if eof(pool_file) then bad_pool('! tex.pool has no check sum.');
@z
@x
    bad_pool('! TEX.POOL line doesn''t begin with two digits.');
@y
    bad_pool('! tex.pool line doesn''t begin with two digits.');
@z
@x
  bad_pool('! TEX.POOL check sum doesn''t have nine digits.');
@y
  bad_pool('! tex.pool check sum doesn''t have nine digits.');
@z
@x
done: if a<>@$ then bad_pool('! TEX.POOL doesn''t match; TANGLE me again.');
@y
done: if a<>@$ then bad_pool('! tex.pool doesn''t match; tangle me again.');
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [7.109] glue_ratio 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@!glue_ratio=real; {one-word representation of a glue expansion factor}
@y
@!glue_ratio=ShortReal; {one-word representation of a glue expansion factor}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [8.110] ranges for quarter,half words FIXTHIS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
if the subrange is `|-128..127|'.

The present implementation tries to accommodate as many variations as possible,
so it makes few assumptions. If integers having the subrange
`|min_quarterword..max_quarterword|' can be packed into a quarterword,
and if integers having the subrange `|min_halfword..max_halfword|'
can be packed into a halfword, everything should work satisfactorily.

It is usually most efficient to have |min_quarterword=min_halfword=0|,
so one should try to achieve this unless it causes a severe problem.
The values defined here are recommended for most 32-bit computers.

@d min_quarterword=0 {smallest allowable value in a |quarterword|}
@d max_quarterword=255 {largest allowable value in a |quarterword|}
@d min_halfword==0 {smallest allowable value in a |halfword|}
@d max_halfword==65535 {largest allowable value in a |halfword|}
@y
if the subrange is `|-128..127|'.

For Berkeley {\mc UNIX} (SunOS) we need to do the |-128..127| kind of range.

@d min_quarterword=-128 {smallest allowable value in a |quarterword|}
@d max_quarterword=127 {largest allowable value in a |quarterword|}
@d min_halfword==-32768 {smallest allowable value in a |halfword|}
@d max_halfword==32767 {largest allowable value in a |halfword|}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [11.165] fix the word "free" so that it doesn't conflict with a runtime proc
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
been included. (You may want to decrease the size of |mem| while you
@^debugging@>
are debugging.)
@y
been included. (You may want to decrease the size of |mem| while you
@^debugging@>
are debugging.)

@d free==free_arr
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [12.186] glue_ratio fix  FIXTHIS
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
floating point underflow on the author's computer.
@^system dependencies@>
@^dirty \PASCAL@>

@<Display the value of |glue_set(p)|@>=
g:=float(glue_set(p));
if (g<>float_constant(0))and(glue_sign(p)<>normal) then
  begin print(", glue set ");
  if glue_sign(p)=shrinking then print("- ");
  if abs(mem[p+glue_offset].int)<@'4000000 then print("?.?")
  else if abs(g)>float_constant(20000) then
    begin if g>float_constant(0) then print_char(">")
    else print("< -");
    print_glue(20000*unity,glue_order(p),0);
    end
  else print_glue(round(unity*g),glue_order(p),0);
@^real multiplication@>
  end
@y
floating point underflow on the author's computer.
For the {\mc VAX}, the only possible random value that could hurt is
a reserved value with 1 in the sign bit and 0 for the (excess) exponent.
Because the sign-plus-exponent is in the middle of the word, the chances
of this happening are miniscule, and ignored here.
@^system dependencies@>
@^dirty \PASCAL@>

@<Display the value of |glue_set(p)|@>=
g:=float(glue_set(p));
if (g<>float_constant(0))and(glue_sign(p)<>normal) then
  begin print(", glue set ");
  if glue_sign(p)=shrinking then print("- ");
  if abs(float(glue_set(p)))>20000.0 then
     begin if float(glue_set(p))>0 then print_char(">")
     else print("< -");
     print_glue(20000*unity,glue_order(p),0);
     end
  else print_glue(round(float(glue_set(p))*unity),glue_order(p),0);
@^real multiplication@>
  end
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [17.241] fix_date_and_time
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ 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 specifies July 4, 1776, at noon; but
users probably want a better approximation to the truth.

@p procedure fix_date_and_time;
begin time:=12*60; {minutes since midnight}
day:=4; {fourth day of the month}
month:=7; {seventh month of the year}
year:=1776; {Anno Domini}
end;
@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 is calls an externally defined |date_and_time|, even though it could
be done from Pascal.
The external procedure also sets up interrupt catching.
@^system dependencies@>

@p procedure fix_date_and_time;
begin
    date_and_time(time,day,month,year);
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.513] area and extension rules
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ The file names we shall deal with for illustrative purposes have the
following structure:  If the name contains `\.>' or `\.:', the file area
consists of all characters up to and including the final such character;
otherwise the file area is null.  If the remaining file name contains
`\..', the file extension consists of all such characters from the first
remaining `\..' to the end, otherwise the file extension is null.
@^system dependencies@>

We can scan such file names easily by using two global variables that keep track
of the occurrences of area and extension delimiters:

@<Glob...@>=
@!area_delimiter:pool_pointer; {the most recent `\.>' or `\.:', if any}
@!ext_delimiter:pool_pointer; {the relevant `\..', if any}
@y
@ The file names we shall deal with for SunOS have the
following structure:  If the name contains `\./', the file area
consists of all characters up to and including the final such character;
otherwise the file area is null.  If the remaining file name contains
`\..', the file extension consists of all such characters from the first
remaining `\..' to the end, otherwise the file extension is null.
@^system dependencies@>

We can scan such file names easily by using two global variables that keep
track of the occurrences of area and extension delimiters:

@<Glob...@>=
@!area_delimiter:pool_pointer; {the most recent `\./', if any}
@!ext_delimiter:pool_pointer; {the most recent `\..', if any}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.514] TeX area directories
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d TEX_area=="TeXinputs:"
@.TeXinputs@>
@d TEX_font_area=="TeXfonts:"
@.TeXfonts@>
@y
Under Linux, the default paths are specified in a separate
file, `\.{texpaths.h}'.  The file opening procedures do path searching
based either on those default paths, or on paths given by the user
in ``environment'' variables.
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.516] more_name
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
  if (c=">")or(c=":") then
@y
  if c="/" then
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.520] default format
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@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 Linux we don't give the area part, instead depending
on the path searching that will happen during file opening.

@d format_default_length=9 {length of the |TEX_format_default| string}
@d format_area_length=0 {length of its area part}
@d format_ext_length=4 {length of its `\.{.fmt}' part}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.521] plain format location
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
TEX_format_default:='TeXformats:plain.fmt';
@y
TEX_format_default:='plain.fmt';
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.524] format file opening: only try once, with path search
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
  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);
  if w_open_in(fmt_file) then goto found;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.525] make_name_string
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
which simply makes a \TeX\ string from the value of |name_of_file|, should
ideally be changed to deduce the full name of file~|f|, which is the file
most recently opened, if it is possible to do this in a \PASCAL\ program.
@^system dependencies@>

This routine might be called after string memory has overflowed, hence
we dare not use `|str_room|'.

@p function make_name_string:str_number;
var k:1..file_name_size; {index into |name_of_file|}
begin if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
 (cur_length>0) then
  make_name_string:="?"
else  begin for k:=1 to name_length do append_char(xord[name_of_file[k]]);
  make_name_string:=make_string;
  end;
end;
@y
which simply makes a \TeX\ string from the value of |name_of_file|, should
ideally be changed to deduce the full name of file~|f|, which is the file
most recently opened, if it is possible to do this in a \PASCAL\ program.
With the Berkeley {\mc UNIX} version, we know that |real_name_of_file|
contains |name_of_file| prepended with the directory name that was found
by path searching.
If |real_name_of_file| starts with |'./'|, we don't use that part of the
name, since {\mc UNIX} users understand that.
@^system dependencies@>

This routine might be called after string memory has overflowed, hence
we dare not use `|str_room|'.

@p function make_name_string:str_number;
var k,@!kstart:1..file_name_size; {index into |name_of_file|}
begin
k:=1;
while (k<file_name_size) and (xord[real_name_of_file[k]]<>" ") do
    incr(k);
name_length:=k-1; {the real |name_length|}
if (pool_ptr+name_length>pool_size)or(str_ptr=max_strings)or
 (cur_length>0) then
  make_name_string:="?"
else begin
  if (xord[real_name_of_file[1]]=".") and (xord[real_name_of_file[2]]="/") then
      kstart:=3
  else
      kstart:=1;
  for k:=kstart to name_length do append_char(xord[real_name_of_file[k]]);
  make_name_string:=make_string;
  end
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [29.537] a_open_in of \input file needs path selector
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
  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
  if a_open_in(cur_file,input_file_path) then goto done;
  if cur_ext=".tex" then
    begin pack_file_name(cur_name,cur_area,"");
    if a_open_in(cur_file,input_file_path) then goto done;
    end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [30.563] opening tfm file: now path searching is done
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Set temp_int to value of first byte
@x
@ @<Open |tfm_file| for input@>=
file_opened:=false;
if aire="" then pack_file_name(nom,TEX_font_area,".tfm")
else pack_file_name(nom,aire,".tfm");
if not b_open_in(tfm_file) then abort;
file_opened:=true
@y
@ Here we have to ``prime the pump'' for the |temp_int| trick explained below.

 @<Open |tfm_file| for input@>=
file_opened:=false;
pack_file_name(nom,aire,".tfm");
if not b_open_in(tfm_file) then abort;
begin  temp_int:=tfm_file^;
      if temp_int<0 then temp_int:=temp_int+256;
end;
file_opened:=true
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [49.1275] a_open_in of \read file needs path specifier
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
  if a_open_in(read_file[n]) then read_open[n]:=just_open;
@y
  if a_open_in(read_file[n],read_file_path) then read_open[n]:=just_open;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [51.1332] Delete ready_already; also add call to set_paths;
%	    also add call to exit() depending upon value of `history'
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ Now this is really it: \TeX\ starts and ends here.

The initial test involving |ready_already| should be deleted if the
\PASCAL\ runtime system is smart enough to detect such a ``mistake.''
@y
@ Now this is really it: \TeX\ starts and ends here.

At the end of the job, we look at |history| to decide the correct
exit code.  We use 1 if |history <= warning_issued| and 0 otherwise.

@d UNIXexit==e@&x@&i@&t
@z

@x
t_open_out; {open the terminal for output}
if ready_already=314159 then goto start_of_TEX;
@y
t_open_out; {open the terminal for output}
set_paths;
@z

@x
start_of_TEX: @<Initialize the output routines@>;
@y
start_of_TEX: argv(0,my_name); FIXTHIS: DELETE MY_NAME!
if (my_name<>'initex')and(my_name<>'triptex') then
  begin if my_name = 'tex' then name_of_file:='plain.fmt'
  else name_of_file:=my_name+'.fmt';
  if w_open_in(fmt_file) then
    if not load_fmt_file then
      begin w_close(fmt_file); goto final_end;
      end
    else w_close(fmt_file);
  end;
@<Initialize the output routines@>;
@z

@x
final_end: ready_already:=0;
@y
final_end: ready_already:=0;
if (history <= warning_issued) then
    UNIXexit(0)
else
    UNIXexit(1);
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [51.1333] print new line before termination; switch to editor if nec.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
    slow_print(log_name); print_char(".");
    end;
  end;
@y
    slow_print(log_name); print_char(".");
    end;
  end;
print_ln;
if (ed_name_start<>0) and (interaction>batch_mode) then
    calledit(str_pool[ed_name_start],ed_name_length,edit_line);
@z