Re^5: Apache +XML parsing

Hi again.
I have taken XML::Rules for a ride, and it is really nice. It also looks very fast. All in all, a great tool.
But it did take me a while to get the inner logic of how it works, despite your evident efforts at writing the documentation. It is in the end excellent as a reference, but as far as I am concerned it lacked a bit in terms of being a tutorial, although I understand that the matter is complex and not easy to explain simply.
What was not evident, is how one deals with a frequent case where a given <tag> can be a subtag of different parent tags, and needs to be interpreted differently depending on that, like <average-color> below :

<fruits>
  <average-color>purple</average-color>
  <fruit type="banana">
    <average-color>yellow</average-color>
  </fruit>
  <fruit type="apple">
    <average-color>greenish</average-color>
  </fruit>
</fruits>
[download]

I could never get the "somewhat x-path-like" tags to work, so I resorted to :

  'average-color' => sub {
      if ($_[2]->[-1] eq 'fruit') {
        # parent tag is <fruit>
        return 'fruit-average-color' => $_[1]->{_content};
      } elsif ($_[2]->[-1] eq 'fruits') {
        # parent tag is <fruits>
        return 'global-average-color' => $_[1]->{_content};
      } else {
        # anything else, discard
        return undef;
      }
   },
[download]

Another aspect a bit mysterious is how exactly the following construct actually works :

  'tag' => sub {
     return '@'.$_[0] => $_[1]->{_content};
  },
[download]

I mean, I know it works and returns the contents of <tag>s as an array, but the way in which it does that is a bit mysterious, even after looking at the module code (I must admit that a lot remains mysterious to me, after looking at the code though).

All in all, thanks for the tip, and thanks for the module. I will re-use it.

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Re^6: Apache +XML parsing
by Jenda (Abbot) on Nov 18, 2008 at 15:21 UTC

Thanks. I'll see if I can improve the docs. Especially regarding the "x-path-like" stuff. That thing is fairly underdocumented.

The code without using the "helper" would be

use XML::Rules;

my $parser = XML::Rules->new(
    stripspaces => 7,
    rules => {
        fruit => 'as array',
        fruits => 'pass no content',
        'average-color' => [
            'fruit' => sub {return 'fruit-average-color' => $_[1]->{_c
+ontent}},
            'fruits' => sub {return 'global-average-color' => $_[1]->{
+_content}},
            sub {},
        ]
    }
);

my $data = $parser->parse(\*DATA);
use Data::Dumper;

print Dumper($data);

__DATA__
<fruits>
  <average-color>purple</average-color>
  <fruit type="banana">
    <average-color>yellow</average-color>
  </fruit>
  <fruit type="apple">
    <average-color>greenish</average-color>
  </fruit>
</fruits>
[download]

Jenda
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