use MT::Template::Context;
MT::Template::Context->add_global_filter(links2rdf => \&links2rdf);

use HTML::LinkExtor;
use URI::URL;

my @links = ();

sub links2rdf {
	my ($text,$val,$ctx) = shift;
	@links = ();
	$parser = HTML::LinkExtor->new(\&callback);
	$parser->parse($text);
	return join("\n",map { "<xlink:href rdf:resource=\"".entityescape($_)."\" />" } @links);
}

sub entityescape {
	my ($data) = @_;
	$data =~ s/\&/\&amp;/g;
	$data =~ s/</\&lt;/g;
	$data =~ s/>/\&gt;/g;
	$data =~ s/"/\&quot;/g;
	$data =~ s/'/\&apos;/g;
	return $data;
}

sub callback {
	my($tag, %attr) = @_;
	return if $tag ne 'a';
	push(@links, $attr{'href'});
}

1;