use strict;
use warnings;

use XML::Twig;

$|++;

my $twig = XML::Twig->new(
    twig_handlers => {

        # as noted in the documentation for end_tag_handlers ...
        # "twig_handlers are called when an element is completely parsed"
        # so should be safe to purge here
        'Book' => sub {
            my ($twig, $el) = @_;
#            print "purging ...\n";
            $twig->purge;
        },

        'Book//*' => sub {
            # see http://search.cpan.org/~mirod/XML-Twig-3.49/Twig.pm#cond
            # for #ELT which is an element
            print $_->tag, ': ', $_->text, $/
                unless ($_->has_children('#ELT'));
        }

    }
);
$twig->parsefile('books.xml');