Problems with default twig handler in XML::Twig

Zoogie has asked for the wisdom of the Perl Monks concerning the following question:

I'm currently using XML::Twig to handle processing of XML documents, and have run into a snag regarding setting a default twig handler. We want to use the "_default_" twig handler to print a warning about unrecognized elements for development (and validation) purposes, but XML::Twig doesn't seem to be calling the "_default_" twig handler at all.

I've created a minimal test program and test XML document that illustrates the problems we're having:

#!/usr/bin/perl -w

# twigtest.pl

use strict;
use XML::Twig;

my $t = new XML::Twig(
        TwigHandlers => {
            'download' => \&tag_download,
            '_default_' => \&tag__default,
            }
        );
if (!($t->safe_parsefile('test.xml'))) {
    warn("Error: Test XML had processing errors: $@\n");
}

# Handles the <download> tag.
sub tag_download {
    my ($t,$elt) = @_;
    
    print("Found a <download>!\n");
    
    $t->purge();
}

# Handles any unrecognized tag.
sub tag__default {
    my ($t,$elt) = @_;
    
    print("Unrecognized tag: <".$elt->gi().">!\n");
    
    $t->purge();
}
[download]

Here's the test XML document (named "test.xml"):

<?xml version="1.0" ?>
<download>
  <oops/>
</download>
[download]

The output from running "./twigtest.pl" is:

Found a <download>!
[download]

which seems to indicate that tag__default isn't being called by XML::Twig.

The version of Perl we're using is 5.005_03, haven't yet had a chance to try it on 5.6.1. XML::Twig version is 2.02. Am I doing something wrong? Has anybody else experienced this problem?

- Zoogie

Comment on Problems with default twig handler in XML::Twig Select or Download Code

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Re: Problems with default twig handler in XML::Twig
by mirod (Canon) on Oct 14, 2001 at 04:44 UTC

Yep! You found a bug! It is fixed on the version of XML::Twig 3.00 that's on my site at www.xmltwig.com.

As a general rule XML::Twig is not really impacted by various versions of Perl, except that after 5.6.0 it can use WeakRefs to gain proper garbage collection. It is impacted by versions of XML::Parser though, and I must say that if I can (if there are no problems with the expat version included in mod_perl) I tend to stick to version 2.27 as XML::Twig was written for it's API, and as it is cleaner Unicode-wise.

BTW If you need a patch for XML::Twig 2.02 please let me know.

[reply]


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