#!/bin/perl
use strict;
use warnings;
use XML::Twig;
use Tie::IxHash;

my %Items;
tie %Items, "Tie::IxHash";
my $xml = <<XML;
<Catalog>
  <item>
    <quantities>
      <prices/>
    </quantities>
    <sellingpoints/>
  </item>
  <item>
    <quantities>
      <prices/>
    </quantities>
    <sellingpoints/>
  </item>
</Catalog>
XML

my $twig = XML::Twig->new( twig_handlers => { _all_ => \&handler, } );
$twig->parse($xml);    # build it
$twig->purge;          # clear end of document from memory

print "\n";
print "$_ => $Items{$_}\n" for keys %Items;


sub handler {
    my $Item_master_Ancestory = $_->ancestors;
    my $element_match         = $_->tag;
    my $text                  = $_->trimmed_text;
    my $coupled               = join
        ' - ', "  " x $Item_master_Ancestory,
        $element_match, keys %{ $_->atts }, values %{ $_->atts }, $text;

    ++$Items{$coupled};
    print "$coupled: $Items{$coupled}\n";
}