Am I doing something wrong?

Yup. Yer using poorly documented OSS software ;)

The SYNOPSIS is badly outdated; I've updated it. The SYNOPSIS in the released version dates from before I made X::F::D more compliant with XPath. The updated SYNOPSIS looks like:

    use XML::Filter::Dispatcher qw( :all );

    my $f = XML::Filter::Dispatcher->new(
        Rules => [
            'foo'               => \&handle_foo_start_tag,
            '@bar'              => \&handle_bar_attr,

            ## Send any <foo> elts and their contents to $handler
            'snarf//self::node()'  => $handler,

            ## Print the text of all <description> elements
            'description' 
                    => [ 'string()' => sub { push @out, xvalue } ],
        ],

        Vars => {
            "id" => [ string => "12a" ],
        },
    );
[download]

The change that affects you is that string() now only looks at the first node in the nodeset as per XPath, so you need to get X::F::D to visit all the desired element nodes and then call string() nodes.

There's now a t/synopsis.t that has the audacity to test the code from the SYNOPSIS. The next release will be heading CPANward as soon as I submit this.

Thanks for the bug report.

- Barrie

P.S. I only found this question thanks to Matt Sergeant mentioning it. In general, while perlmonks is a nice resource, I recommend posting XML related questions to the perl-xml@listserv.ActiveState.com mailing list.