use strict;
use XML::Rules;
use Data::Dumper;

my $parser = XML::Rules->new(
	rules => {
		'excerpt' => 'pass no content',
	  'Address,Fax,Telefon,contactinfo,products' => 'no content',
	  'Boss,Building,Name,Ort,Street,URL,art_code,code,directcall,email,quantity,quantity_small,telnumber,unitnumber,zip' => 'content',
	  'article' => sub {
		if (exists $_[1]->{quantity_small}) {
			return #'%article' =>{
				$_[1]->{art_code} => 'few' # };
		} else {
			return #'%article' => {
				$_[1]->{art_code} => $_[1]->{quantity} #};
		}
	  },
	  'unit' => 'no content by Name',
	}
);

my $data = $parser->parse(\*DATA);

print Dumper($data);

__DATA__
<excerpt>
<unit>
<unitnumber>1</unitnumber>
...