XML::Twig how to find a parent's attribute

slugger415 has asked for the wisdom of the Perl Monks concerning the following question:

Hi Monks, quick question I couldn't find in the documentation (or didn't understand the syntax) for XML::Twig - how do I match a parent or ancestor's attribute? For instance, I have some XML:

<p conref="hello">
 <ul>
  <li>Bob</li>
  <li>Mary</li>
 </ul>
</p>
[download]

If I'm evaluating li elements, I want to know if one of its parents has a conref attribute set. What's the syntax for that?

$elt->parent();

... returns the parent, which would be ul in this case, but how do I match the ancestor that contains the attribute I'm looking for?

The doc says this about parent:

parent ($optional_condition)
Return the parent of the element, or the first ancestor matching the $optional_condition

Just not sure how to phrase the optional_condition here.

thanks, Scott

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Re: XML::Twig how to find a parent's attribute by AppleFritter (Vicar) on Jul 25, 2014 at 18:34 UTC
Looking at XML::Twig's source, you can apparently pass subroutine references, regular expressions, or plain strings (which can themselves be used in various ways to express different things). Take a look at the `_install_cond` subroutine.	[reply]
Re: XML::Twig how to find a parent's attribute by poj (Abbot) on Jul 25, 2014 at 18:55 UTC
`$elt->parent('p[@conref != ""]')` Read more... (866 Bytes) poj	[reply] [d/l] [select]
Re^2: XML::Twig how to find a parent's attribute by slugger415 (Monk) on Jul 26, 2014 at 01:03 UTC
Thanks poj, though I should have mentioned, I won't always know that the ancestor is a p; it could be anything. Anyway to grab "whatever it is"?	[reply]
Re^3: XML::Twig how to find a parent's attribute by poj (Abbot) on Jul 26, 2014 at 05:19 UTC
`sub li { my ($t,$elt) = @_; my $e = $elt->parent('[@conref != ""]'); # p removed if ( defined $e ){ print $e->tag." ".$elt->text."\n"; } }` [download] poj	[reply] [d/l]