#! /usr/bin/perl

use strict;
use warnings;
use XML::Twig;

my $file = $ARGV[0];

my $twig= new XML::Twig(
    TwigRoots=>{geography=>1},
    TwigHandlers=>    {    'node' =>\&geog_node
                    }
    
);

$twig->parsefile($file);

sub geog_node {
    my($twig, $node) = @_;
    # ancestors_or_self returns the node first, the ancestors from inner to outter
    # hence the reverse
    foreach my $node_to_output ( reverse $node->ancestors_or_self( 'node[!@output]')) { 
        if($node_to_output->att('hidden') eq '0') { 
            print node_summary( $node_to_output); 
        }
        $node_to_output->set_att( output => 1); # mark so we don't try to output them again
    }
    $twig->purge;                               # now it's safe to purge 
}

sub node_summary
  { my $node= shift;
    return sprintf "Data for node:\tID:\t%s\n\tDesc:\t%s\n", $node->att('id'),
                                                             $node->field('description')
                                                             ;
  }