BibTeX change file for TOPS-20, culled from Dave Fuchs's
TeX change file, with his permission.
Copyright (C) 1988 by Oren Patashnik.  All rights reserved.

History:
January 1988---The original version of the TOPS-20 change file, for
	BibTeX version 0.99a. The only substantive feature allowed
	specifying the top-level .AUX file in a command line argument.
February 1988---Changed for BibTeX's new version numbers, 0.99b,c.


@x Tell WEAVE to print only the changes:
\pageno=\contentspagenumber \advance\pageno by 1
@y
\pageno=\contentspagenumber \advance\pageno by 1
\let\maybe=\iffalse
\def\ttw{{\mc TOPS-20}}
\def\title{\BibTeX\ changes for \ttw}
@z


@x TOPS-20's banner:
@d banner=='This is BibTeX, Version 0.99c' {printed when the program starts}
@y
@d banner=='This is BibTeX, TOPS-20 Version 0.99c'
@z


@x	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	The space after the B is due to a compiler bug.
@{@&$C-,A+,D-,P:520000@&B@= @>@}
  {no range check, catch arithmetic overflow, no debug overhead,
  move the code up to make room for the global data in production}
@!debug @{@&$C+,D+,P:520000@&B@= @>@}@+ gubed
  {we turn everything on when debugging}
@z


@x Define the compile-time constant |max_rescan| for command-line processing
@!lit_stk_size=100; {maximum number of literal functions on the stack}
@y
@!lit_stk_size=100; {maximum number of literal functions on the stack}
@!max_rescan=500; {maximum length of the rescan buffer}
@z


@x Set the command-line switch
check_cmnd_line := false;			{many systems will change this}
@y
check_cmnd_line := true;
@z


@x
@<Variables for possible command-line processing@>=
@!check_cmnd_line : boolean;	{|true| if we're to check the command line}
@y

@d RSCAN=@'500 {ReSCAN buffer JSYS}

@<Variables for possible command-line processing@>=
@!check_cmnd_line : boolean;	{|true| if we're to check the command line}
@!ac1: integer; {AC1 from Rescan}
@!rescan: packed array[1..max_rescan] of char; {rescan buffer}
@!rescan_len: integer; {amount of |rescan| used}
@!i: integer; {temporary}
@z


@x And finally, here's the code that handles the command line argument.
@<Process a possible command line@>=
begin
do_nothing;		{the ``default system'' doesn't use the command line}
end
@y
\ttw\ puts the user command line into the so-called rescan buffer
(actually, we have to use a real hack to see if it's a bogus Execute,
Start, Continue, Debug, etc.\ command, in which case we should pretend
there was no command line, since the command line that was there was
not intended for \BibTeX).  We copy the command line into the input
buffer, and once we've isolated the (\.{.aux} file-name) argument we
copy that into the |name_of_file| array.

@<Process a possible command line@>=
begin
jsys(RSCAN,1,i;0;ac1); {put the command line into the |TTY| input buffer}
if (i<>2) or (ac1<=0) then goto aux_not_found; {RSCAN failed, somehow}
if eoln(term_in) then read_ln(term_in); {for some TOPS-20's}
read(term_in,rescan:rescan_len); {read in rescan buffer}
if rescan_len>max_rescan then begin
  write_ln(term_out,'Command line longer than ',max_rescan:0,
    ' characters, so I''m ignoring it');
  read_ln(term_in); goto aux_not_found; end;
@/{The following line is based upon experimentation with \ttw!}
if rescan_len=ac1-2 then goto aux_not_found; {EX, ST, DEB commands}
@#
i:=1; while rescan[i]>' ' do incr(i); {skip command name, presumably BibTeX}@/
while (i<=rescan_len) and (rescan[i]=' ') do incr(i); {skip spaces}@/
if i>rescan_len then goto aux_not_found; {there was no argument}
@#
aux_name_length := 0;
while (rescan[i]>' ') do		{copy the argument into |name_of_file|}
    begin
    if (aux_name_length = file_name_size) then
	sam_you_made_the_file_name_too_long;
    incr(aux_name_length);
    name_of_file[aux_name_length] := rescan[i];
    incr(i);
    end;
end
@z