eval 'exec perl -S $0 ${1+"$@"}'
    if 0;

$sentinel     = "<tableofcontents>";
$sentinel_end = "</tableofcontents>";

while (<>) {
    push(@file, $_) unless (/^$sentinel/ .. /^$sentinel_end/);
    push(@file, $_) if (/^$sentinel/ || /^$sentinel_end/);
}

$intro = -1;

$outerlevel = 1;

$curlevel = $outerlevel;
foreach $i (0..$#file) {

    if ($file[$i] =~ m|$sentinel|) {$intro = $i;}

    next unless $file[$i] =~ m|<[hH]([23])>\s*((.*\S)*)\s*</[hH]\1>|;
    $nowlevel = $1;
    $label = $heading = $2;

    while ($nowlevel > $curlevel) {
      push(@toc, "<ul compact>\n");
      $curlevel++;
    }
    while ($nowlevel < $curlevel) {
      push(@toc, "</ul>\n");
      $curlevel--;
    }
    if ($file[$i] =~ m/name="([^"]+)"/i) {
	$label = $1;
        $heading =~ s/name="/href="#/i;
        push(@toc, "<li>$heading\n");
    } else {
	$label =~ s/\W//g;
	$label =~ tr/A-Z/a-z/;
	$label = substr($label, 0, 6) . "00";
	$label++ while (defined $labels{$label});
#	$file[$i] =~ s|\Q$heading\E|<a name="$label">$&</a>|;
	$file[$i] =~ s|$heading|<a name="$label">$&</a>|;
        push(@toc, qq{<li><a href="#$label">$heading</a>\n});
    }
    $labels{$label}++;
}
$nowlevel = $outerlevel;
while ($nowlevel > $curlevel) {
  push(@toc, "<ul compact>\n");
  $curlevel++;
}
while ($nowlevel < $curlevel) {
  push(@toc, "</ul>\n");
  $curlevel--;
}

if ($intro >= 0) {
  print @file[0..$intro];
  print @toc;
  print @file[$intro+1 .. $#file];
} else {
  print @file;
}