#!/usr/bin/perl

$camllight = "TERM=dumb ocaml";
$camlbegin = "\\caml\n";
$camlend = "\\endcaml\n";
$camlin = "\\?";
$camlout = "\\:";
$camlblank = "\\;\n";

$linelen = 72;
$output = "";
$cut_at_blanks = 0;

while ($#ARGV >= 0) {
  $_ = $ARGV[0];
  last unless (/^-/);
  $linelen = $ARGV[1], shift, shift, next    if (/^-n$/);
  $output  = $ARGV[1], shift, shift, next    if (/^-o$/);
  $camllight = $ARGV[1], shift, shift, next    if (/^-caml$/);
  $cut_at_blanks = 1, shift, next            if (/^-w$/);
  printf STDERR ("Unknown option '%s', ignored\n", $_);
  shift;
}

# First pass: extract the Caml phrases to evaluate

open(ML, "> .input.ml") || die("Cannot create .input.ml : $!");

foreach $infile (@ARGV) {
  open(IN, $infile) || die("Cannot open $infile : $!");
  while(<IN>) {
    if (m/^\\begin{caml_(example|example\*|eval)}\s*$/) {
      while(<IN>) {
        last if m/^\\end{caml_(example|example\*|eval)}\s*$/;
        print ML $_;
      }
    }
  }
  close(IN);
}

close(ML);

# Feed the phrases to a Caml toplevel

open(TOPLEVEL, "$camllight 2>&1 < .input.ml |") ||
       die("Cannot start camllight : $!");

<TOPLEVEL>; <TOPLEVEL>;	        # skip the banner
$lastread = <TOPLEVEL>;
$lastread =~ s/^# //;

# Second pass: shuffle the TeX source and the output of the toplevel

if ($output) {
  if ($output eq "-") {
    open(OUT, ">&STDOUT");
  } else {
    open(OUT, ">$output") || die("Cannot create $output: $!");
  }
}

foreach $infile (@ARGV) {
  open(IN, $infile) || die("Cannot open $infile: $!");
  if (! $output) {
    $outfile = $infile;
    $outfile =~ s/\.tex$//;
    open(OUT, "> $outfile.ml.tex") || die("Cannot create $outfile.ml.tex: $!");
  }
  while(<IN>) {
    if (m/^\\begin{caml_example(\*?)}\s*$/) {
      $omit_answer = $1;     # true if caml_example*, false if caml_example
      print OUT $camlbegin;
      $severalphrases = 0;
      while(<IN>) {
        last if m/\\end{caml_example\*?}\s*$/;
        print OUT $camlblank if ($severalphrases);
        while(1) {
          s/\\/\\\\/g;
          print OUT $camlin, $_;
          last if m/;; *$/;
          $_ = <IN>;
        }
	while ($lastread =~ s/^  //) { }
        while($lastread) {
          last if $lastread =~ s/^# //;
          print STDERR $lastread;
          if (! $omit_answer) {
            while (length($lastread) > $linelen) {
              if ($cut_at_blanks) {
                $cutpos = rindex($lastread, ' ', $linelen);
                if ($cutpos == -1) { $cutpos = $linelen; } else { $cutpos++; }
              } else {
                $cutpos = $linelen;
              }
              $line = substr($lastread, 0, $cutpos);
              $line =~ s/\\/\\\\/g;
              print OUT $camlout, $line, "\n";
              $lastread = substr($lastread, $cutpos,
                                 length($lastread) - $cutpos);
            }
            $lastread =~ s/\\/\\\\/g;
            print OUT $camlout, $lastread;
	  }
          $lastread = <TOPLEVEL>;
        }
        $severalphrases = 1;
      }
      print OUT $camlend;
    }
    elsif (m/^\\begin{caml_eval}\s*$/) {
      while(<IN>) {
        last if m/^\\end{caml_eval}\s*$/;
        if (m/;; *$/) {
          while ($lastread =~ s/^  //) { }
	  while($lastread) {
	    last if $lastread =~ s/^#//;
	    print STDERR $lastread;
	    $lastread = <TOPLEVEL>;
	  }
        }
      }
    }
    else {
      print OUT $_;
    }
  }
  close(IN);
}

close(TOPLEVEL);