#!/usr/bin/perl


{
    package MyParser;
    use base HTML::Parser;
    my @Numbers;
    my $Separator = ".";
    my $Alphabet = join("", (' ', 'a'..'z'));
    my $Style = 1;
    my $ThisSection = "none";
    my %References;
    my $StoreOnly = 0;
    my $Debug = 0;

    sub NumberStyle
    {
	my ($Number, $Part, $Level) = @_;

	# Example: Display chapter numbers, where <h1> is a chapter
	if($Style == 4)
	{
	    return("Chapter $Number") if($Level == 1);
	    return("");
	}

	# Example: Alphabetic numbering
	return(substr(uc($Alphabet), $Number, 1)) if($Style == 2);
	return(substr(lc($Alphabet), $Number, 1)) if($Style == 3);

	# Example: Number only down to a depth of 1.1.1
	if($Style == 5)
	{
	    $Depth = 3;
	    return($Number) if($Level <= $Depth);
	    return("");
	}

	# Example: Use the format "1.1.a"
	if($Style == 6)
	{
	    $Depth = 3;
	    return("") if($Level > $Depth);
	    return($Number) if($Part < $Depth);
	    return(substr(lc($Alphabet), $Number, 1)) if($Part == $Depth);
	    return("");
	}

	# Default: Numeric "1.1.1.1.1"
	return($Number);
    }


    sub start 
    {
	my($self, $tagname, $attr, $attrseq, $origtext) = @_;

	# Handle the start of heading tags
	if($tagname =~ /^h([1-6])$/i)
	{
	    $Level = $1;

	    # Update the numbering
	    $Numbers[$Level]++;
	    if($Level < 6) 
	    {
		foreach $LowerLevel ($Level + 1 .. 6) 
		{
		    $Numbers[$LowerLevel] = 0;
		}

	    }   


	    # Append the numbering information to the tag
	    my @Parts;
	    foreach $Loop (1..$Level)
	    {
		$Part = NumberStyle($Numbers[$Loop], $Loop, $Level);
		push(@Parts, $Part) if($Part); 
	    }
	    $Numbering = join($Separator, @Parts);
	    $ThisSection = $Numbering;
	    print "<h$Level>" . $Numbering . " " unless $StoreOnly;
	    

	}
	elsif($tagname =~ /^body$/)
	{
	    for(1..6)
	    {
		$Numbers[$_] = 0;
	    }
	}
	elsif($tagname =~ /^ref$/)
	{
	    $ReferenceName = $$attr{"name"};
	    $References{$ReferenceName} = $ThisSection;
	    print "<b> [Stored reference &quot;$ReferenceName&quot; as $ThisSection] </b>" if( $Debug && ! $StoreOnly);

	}
	elsif($tagname =~ /^xref$/)
	{
	    $ReferenceName = $$attr{"name"};
	    print " !!! X-ref: $ReferenceName: " if( $Debug && ! $StoreOnly);
	    print $References{$ReferenceName} . "</b>" unless $StoreOnly;

	}
	else 
	{
	    # Start of tags which are not headers
	    print $origtext unless $StoreOnly;
	}
    }

    sub end
    {
        my($self, $tagname, $origtext) = @_;
        print $origtext unless $StoreOnly;
    }

    sub text 
    {
        my($self, $origtext, $is_cdata) = @_;
        print $origtext unless $StoreOnly;
    }
    sub storeOnly
    {
	$StoreOnly = 1;
    }

    sub storeAndDisplay
    {
	$StoreOnly = 0;
    }
    sub debugMode
    {
	$Debug = 1;
    }

}

$Parser = MyParser->new();

my $Data = join('', <>);

$Parser->debugMode() if(0);
$Parser->storeOnly();
$Parser->parse($Data);

$Parser->storeAndDisplay();
$Parser->parse($Data);