I've been puzzling over this too long, and am sure I'm just not looking at it the right way. Hopefully someone with some experience with XML::Twig will have a suggestion.

I'm working on improving some of the datastructures returned by PerlMonks::Mechanized. One of the easiest ones to work with is just eluding me. Specifically, I'm updating the method that parses the Monastery's XML thread ticker returning a concise but useful datastructure.

The problem is that the datastructure returned by XML::Twig (and previously XML::Simple) isn't as simple as it should be; it contains extra levels of indirection that are unneeded.

It wouldn't be all that hard to simply traverse the structure returned by XML::Twig, modifying the datastructure to remove extra indirection, but somehow I believe XML::Twig is capable of giving me what I want in the first place. But over the past few days I've convinced myself that I don't understand XML::Twig enough to get the most out of this highly flexible module.

Here is a simplified snippet of code that gives an example of what I'm doing.

use strict;
use warnings;
use XML::Twig;
use Data::Dumper;


my $xml;
{
    local $/ = '';
    $xml = <DATA>;
}

print $xml, "\n";

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

$twig->safe_parse( $xml );

my $struct = $twig->simplify( 
    forcearray => 1, 
    keyattr => [ qw/id/ ],
#    group_tags => { 'node id' => 'id' }, 
);

print Dumper $struct;

__DATA__
<?xml version="1.0" encoding="ISO-8859-1"?>
<thread id="504929">
<node id="504941">
</node>
<node id="504942">
<node id="504950">
<node id="504964">
</node>
</node>
<node id="504953">
</node>
</node>
<node id="504944">
</node>
</thread>
[download]

As you can see, I've commented out the group_tags attribute, because it wasn't gaining me anything, at least how I was using it.

The output I'm getting is:

$VAR1 = {
    'node' => {
        '504942' => {
            'node' => {
                '504953' => undef,
                '504950' => {
                    'node' => {
                        '504964' => undef
                    }
                }
            }
        },
        '504941' => undef,
        '504944' => undef
    }
};
[download]

I'm close, but what I really want is:

$VAR1 = {
    '504942' => {
        '504953' => undef,
        '504950' => {
            '504964' => undef
        }
    },
    '504941' => undef,
    '504944' => undef
};
[download]

In other words, the node => {... is extra indirection that I don't need or want.

Any tips on how to coax this out of XML::Twig?