#!/bin/perl -w
use strict;
use XML::Twig;

my $twig= XML::Twig->new(pretty_print=>'indented');

$twig->parse(\*DATA);
my $root=$twig->root;


$twig->root->first_child->sort_children( sub { $_->{'att'}->{"type"}});
$twig->root->first_child->first_child->sort_children( sub { $_->text});
#$twig->root->sort_children_on_att("type");
#$twig->root->sort_children_on_field('mainterm');

$twig->print;
__DATA__
<enhancement>
<descriptorgroup>
<descriptors type="MED" controlled="y">
<descriptor>
<mainterm weight="a">plague</mainterm>
<mainterm>disease</mainterm>
<mainterm>pestilence</mainterm>
</descriptor>
</descriptors>
<descriptors type="DRG" controlled="y">
<mainterm>panadol</mainterm>
<mainterm weight="a">zorro</mainterm>
<mainterm>xenon</mainterm>
<mainterm weight="a">aspirin</mainterm>
</descriptors>
</descriptorgroup>
</enhancement>

##</code><code>##

---------- perl compile ----------
<enhancement>
  <descriptorgroup>
    <descriptors controlled="y" type="DRG">
      <mainterm weight="a">aspirin</mainterm>
      <mainterm>panadol</mainterm>
      <mainterm>xenon</mainterm>
      <mainterm weight="a">zorro</mainterm>
    </descriptors>
    <descriptors controlled="y" type="MED">
      <descriptor>
        <mainterm weight="a">plague</mainterm>
        <mainterm>disease</mainterm>
        <mainterm>pestilence</mainterm>
      </descriptor>
    </descriptors>
  </descriptorgroup>
</enhancement>

Output completed (3 sec consumed) - Normal Termination