#! /usr/bin/perl -w
#
# htmltoc - a tool to make a table of contents from a particular html document.
#
# Copyright (C) 1999 Satoru Takabayashi <satoru-t@is.aist-nara.ac.jp>
#     All rights reserved.
#     This is free software with ABSOLUTELY NO WARRANTY.
#
# You can redistribute it and/or modify it under the terms of 
# the GNU General Public License version 2.
#

use NKF;

$_ = join '', <>;
$_ = nkf("-e", $_);

my $n = 0;
while (1) {
    if (s/^\s*<h([2-6])[^>]*><a name="([^"]*)">([^<>]*)<\/a><\/h\1>//ism) {
	$level   = $1;
	$anchor  = $2;
	$heading = $3;
    } elsif (s/^\s*<h([2-6].*?) id="([^"]*)">([^<>]*)<\/h\1>//ism) {
	$level   = $1;
	$anchor  = $2;
	$heading = $3;
    } else {
	last;
    };
    if ($level > $n) {
	print "  " x ($level - 2);
	print "<ul>\n";
    } elsif ($level < $n) {
	for ($i = $level; $i < $n; $i++) {
	    print "  " x ($n - $i);
	    print "</ul>\n";
	}
    }
    $n = $level;
    print "  " x ($n - 2);
    print "<li><a href=\"#$anchor\">$heading</a>\n";
}
for ($i =  1; $i < $n; $i++) {
    print "  " x ($n - $i -1);
    print "</ul>\n";
}