@x Tell WEAVE to print only the changes:
\pageno=\contentspagenumber \advance\pageno by 1
@y we insert stuff that causes only the changes to be TeXed
\def\botofcontents{\vfill
\centerline{(This listing shows the changes for {\sc WAITS} only)}}
\pageno=\contentspagenumber \advance\pageno by 1
\let\maybe=\iffalse
@z
@x Changes for debugging:
@d debug==@{ {change this to `$\\{debug}\equiv\null$' when debugging}
@d gubed==@t@>@} {change this to `$\\{gubed}\equiv\null$' when debugging}
@y (normally it's not changed)
@d debug==@{ {change this to `$\\{debug}\equiv\null$' when debugging}
@d gubed==@t@>@} {change this to `$\\{gubed}\equiv\null$' when debugging}
@z
@x Changes for statistics-gathering:
@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 (normally we gather them, to see if TeX is getting too big)
@d stat== {change this to `$\\{stat}\equiv\.{@@\}}$' when not
	gathering usage statistics}
@d tats== {change this to `$\\{tats}\equiv\.{@@\}}$' when not
	gathering usage statistics}
@z
@x Changes to the compiler directives:
@{@&$C-,A+,D-@} {no range check, catch arithmetic overflow, no debug overhead}
@!debug @{@&$C+,D+@}@+ gubed {but turn everything on when debugging}
@y
@{@&$C-,A+,D-,W+@}{no range check, catch arithmetic overflow, no debug overhead}
@!debug @{@&$C+,D+,W+@}@+ gubed {but turn everything on when debugging}
{the `|W+|' switch catches more syntax errors}
@z
@x System-dependent character set change:
(The present file \.{WEAVE.WEB} does not contain any of the non-ASCII
characters, because it is intended to be used with all implementations of
\.{WEB}.  It was originally created on a Stanford system that has a
convenient extended character set, then ``sanitized'' by applying another
program that transliterated all of the non-standard characters into
standard equivalents.)

@<Set init...@>=
for i1 to @'37 do xchr[i]' ';
@y
The code shown here is intended to be used on the Stanford {\sc SAIL} system,
and at other installations like CMU and ISI where essentially the same
extended character set is used. The fact that {\sc SAIL} has |'}'| in the
wrong place turns out to cause no difficulty in this case.

@<Set initial values...@>=
for i1 to @'37 do xchr[i]chr(i);
xchr[left_arrow]chr(@'137);
xchr[not_equal]chr(@'33);
xchr[@'33]chr(@'176);
@z
@x Opening the input files:
@p procedure open_input; {prepare to read |web_file| and |change_file|}
begin reset(web_file); reset(change_file);
end;
@y
We open the files in a special mode that allows us to distinguish
|form_feed| from |carriage_return|.  Local scuttlebutt says that nine
buffers gives best results at {\mc SAIL}.

@p procedure open_input; {prepare to read |web_file| and |change_file|}
begin reset(web_file,'','/E/N:9'); reset(change_file,'','/E/N:9');
end;
@z
@x Opening |tex_file|:
rewrite(tex_file);
@y
rewrite(tex_file,'','/N:9');
@z
@x Array input for efficiency:
@<Globals...@>=@!buffer: array[0..long_buf_size] of ASCII_code;
@y

We use a special feature of the local \PASCAL\ that
reads text into another array |aux_buffer| first, thus saving
a bunch of procedure-call overhead.

@<Globals...@>=@!buffer: array[0..long_buf_size] of ASCII_code;
@!aux_buffer:array[0..buf_size] of text_char;
@^system dependencies@>
@z
@x New input_ln function:
@p function input_ln(var f:text_file):boolean;
	{inputs a line or returns |false|}
var final_limit:0..buf_size; {|limit| without trailing blanks}
begin limit0; final_limit0;
if eof(f) then input_lnfalse
else	begin while not eoln(f) do
		begin buffer[limit]xord[f^]; get(f);
		incr(limit);
		if buffer[limit-1]" " then final_limitlimit;
		if limit=buf_size then
			begin while not eoln(f) do get(f);
			decr(limit); {keep |buffer[buf_size]| empty}
			if final_limit>limit then final_limitlimit;
			print_nl('! Input line too long'); loc0; error;
@.Input line too long@>
			end;
		end;
	read_ln(f); limitfinal_limit; input_lntrue;
	end;
end;
@y
@p function input_ln(var f:text_file):boolean;
	{inputs a line or returns |false|}
label restart,done;
var n: integer; {the number of characters input by Hedrick's extended |read|}
@!k:0..buf_size; {index into the buffers}
begin restart: if eof(f) then
	begin limit0; input_lnfalse;
	end
else	begin read(f,aux_buffer:n);
	if (line=1)(n=29)(aux_buffer[0]='C')(aux_buffer[8]=chr(@'26)) then
		begin while (f^chr(form_feed))(not eof(f)) do
			begin read_ln(f);
			read(f,aux_buffer:n); {skip file directory page}
			end;
		end;
	if n<buf_size then
		begin limitn;
		if n>0 then for k0 to limit-1 do buffer[k]xord[aux_buffer[k]]
		else if f^=chr(form_feed) then
			begin line((line div @'200000)+1)*@'200000+1;
			read_ln(f); goto restart;
			end;
		end
	else	begin limitbuf_size-1;
		for k0 to limit-1 do buffer[k]xord[aux_buffer[k]];
		print_nl('! Input line too long'); loc0; error;
@.Input line too long@>
		while not eoln(f) do read(f,aux_buffer);
		end;
	loop@+	begin if limit=0 then goto done;
		if buffer[limit-1]" " then goto done;
		decr(limit);
		end;
done:	read_ln(f); input_lntrue;
	end;
end;
@^system dependencies@>
@z
@x Putting the file page number into error messages:
print_ln('l.', line:1, ')');
@y
print_ln('p.',1+(line div @'200000):1,',l.', line mod @'200000:1, ')');
@z
@x New procedure write_end_of_page:
\TeX\ control sequence.
@y
\TeX\ control sequence. The |write_end_of_page| routine is used to
break the output into pages for ease in editing.
@z
@x
@d out5==@+begin oot5
@y
@d out5==@+begin oot5

@p procedure write_end_of_page;
begin if out_ptr>0 then flush_buffer(out_ptr,false);
write(tex_file,xchr[form_feed]); {write a page mark}
out_line((out_line div @'200000)+1)*@'200000+1;
end;
@^system dependencies@>
@z
@x Page number on warning message:
begin print_nl('! Line had to be broken (output l.',out_line:1);
@.Line had to be broken@>
@y
begin print_nl('! Line had to be broken (output p.',
@.Line had to be broken@>
1+(out_line div @'200000):1,',l.',out_line mod @'200000:1);
@^system dependencies@>
@z
@x Page number on trace output header:
	begin print_nl('Tracing after l.',line:1,':'); mark_harmless;
@y
	begin print_nl('Tracing after p.',1+(line div @'200000):1,
		',l.',line mod @'200000:1,':');
@^system dependencies@>
@z
@x Calling write_end_of_page in Phase II:
@<Output the code for the beginning...@>=
out("\");
if buffer[loc-1]"*" then out("M")
@.\\M@>
else	begin out("N"); print('*',module_count:1);
@.\\N@>
	update_terminal; {print a progress report}
	end;
out_mod(module_count); out2(".")(" ")
@y
@<Output the code for the beginning...@>=
if buffer[loc-1]"*" then out2("\")("M")
@.\\M@>
else	begin write_end_of_page; out2("\")("N");
@.\\N@>
	print('*',module_count:1); update_terminal; {print a progress report}
	end;
out_mod(module_count); out2(".")(" ")
@^system dependencies@>
@z
@x Calling write_end_of_page in Phase III:
finish_line; out4("\")("i")("n")("x"); finish_line;
@.\\inx@>
@<Do the first pass of sorting@>;
@<Sort and output the index@>;
@y
finish_line; write_end_of_page; out4("\")("i")("n")("x"); finish_line;
@.\\inx@>
@<Do the first pass of sorting@>;
@<Sort and output the index@>;
write_end_of_page;
@^system dependencies@>
@z