Re^2: Is it possible to parse an XML file recursively using XML::Twig?

[mr_ron]

I had trouble with your second solution that involved " the '_all_' handler, and test each node for having children". When I ran it, as written, I got output like:

(ArrayOfBooks) Book:
(ArrayOfBooks) Book:
(Book) Released:
(ArrayOfBooks) Book:
(ArrayOfBooks) Book:
(ArrayOfBooks) Book:
Can't call method "tag" on an undefined value at monk_twig_xml_leaf2.p
+l line 11.

 at monk_twig_xml_leaf2.pl line 19.
 at monk_twig_xml_leaf2.pl line 19.

I tried commenting out the "purge" call and got empty output with no errors, seemingly because $element->has_children was returning true for "#PCDATA" text nodes. I am new to XML:Twig, but not so new to XML, and am starting to appreciate XML::Twig's potential for optimization. I did come up with some working code as well but would first be interested in what I might be doing wrong that Preceptor's example wouldn't run.

[Preceptor]

Calling tag on undefined value is probably the parent call. Adding a "defined" test there will probably do the trick. But I will suggest that the strength of the module is in using xpath so you rarely need to do a traverse in the first place. ≤/P>

[mr_ron]

The following more cautious code seemed to work for me and should purge memory regularly. I worry that calling purge on every element which might purge something you still need around.

use strict;
use warnings;

use XML::Twig;

$|++;

my $twig = XML::Twig->new(
    twig_handlers => {

        # as noted in the documentation for end_tag_handlers ...
        # "twig_handlers are called when an element is completely pars
+ed"
        # so should be safe to purge here
        'Book' => sub {
            my ($twig, $el) = @_;
#            print "purging ...\n";
            $twig->purge;
        },

        'Book//*' => sub {
            # see http://search.cpan.org/~mirod/XML-Twig-3.49/Twig.pm#
+cond
            # for #ELT which is an element
            print $_->tag, ': ', $_->text, $/
                unless ($_->has_children('#ELT'));
        }

    }
);
$twig->parsefile('books.xml');

[Ppeoc]

This is exactly what I was looking for! Thank you :) I now just need to figure how to have the full nested path for each child. Thank you once again :)