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

Hello,

When feeding XML::Twig with an XML document that defines a default namespace, then all elements that have no prefix get the #default prefix. This is probably due to XML::Parser::Expat

I assumed that using map_xmlns in the XML::Twig constructor will assign my prefix for the default namespace URL but it doesn't.

Here's an example for the XML Document: 

<schema xmlns="http://www.w3.org/2001/XMLSchema">
  <element name="alert"/>
</schema>

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Also, my XML::Twig constructor looks like this: 

my $twig = XML::Twig->new(
    map_xmlns => {
                xsd => 'http://www.w3.org/2001/XMLSchema',
        },
);

[download]

The problem: when I print $twig->root->gi I get #default:schema while I expect to get xsd:schema.

How can I get XML::Twig to do what I expect it to do (show me the prefix that I assigned to the namespace URL and not show me the #default prefix)?

Thanks.

-- DJpumps

Replies are listed 'Best First'.
Re: XML::Twig and #default prefix
by mirod (Canon) on Dec 12, 2007 at 09:26 UTC

    You got the map_xmlns reversed: it should be map_xmlns => { 'http://www.w3.org/2001/XMLSchema' => 'xsd', }.

    I agree that it is easy to make that mistake though, I'll fix that in the next release, either through a warning, or by swapping the args if it looks like they might be reversed. Thanks.

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[d/l]
      Hello,

      I reversed the mapping and I got ns_prefix to report the prefix that I expected, xsd, in this case. That's OK.

      What isn't OK is that namespace returns an empty string and not the namespace URL that I assigned in the mapping. Why?

      Thanks a lot for your rapid response.

      -- DJpumps
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        I get the proper result:

        /usr/bin/perl

use strict;
use warnings;

use XML::Twig;


my $twig = XML::Twig->parse( map_xmlns => { 'http://www.w3.org/2001/XM
+LSchema' => 'xsd', }, \*DATA);

printf "\$twig->root->gi: %s\n", $twig->root->gi;
printf "\$twig->root->namespace: %s\n", $twig->root->namespace;

__DATA__
<schema xmlns="http://www.w3.org/2001/XMLSchema"><element name="alert"
+/></schema>

        [download]

        gives me:

        $twig->root->gi: xsd:schema
$twig->root->namespace: http://www.w3.org/2001/XMLSchema

        [download]

        Which version of XML::Twig are you using? I get the results above with XML::Twig 3.32, the latest CPAN release.

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