xml - Mojo::DOM 是否提供使用嵌套语法的可能性？

Question

如何使用 Mojo::DOM 模块编写此示例？

#!/usr/bin/env perl
use warnings;
use 5.012;
use XML::LibXML;

my $string =<<EOS;
<result>
    <cd>
    <artists>
        <artist class="1">Pumkinsingers</artist>
        <artist class="2">Max and Moritz</artist>
    </artists>
    <title>Hello, Hello</title>
    </cd>
    <cd>
    <artists>
        <artist class="3">Green Trees</artist>
        <artist class="4">The Leons</artist>
    </artists>
    <title>The Shield</title>
    </cd>
</result>
EOS
#/
my $parser = XML::LibXML->new();
my $doc = $parser->load_xml( string => $string );
my $root = $doc->documentElement;

my $xpath = '/result/cd[artists/artist[@class="2"]]/title';

my @nodes = $root->findnodes( $xpath );
for my $node ( @nodes ) {
    say $node->textContent;
}

Answer 1

Mojo::DOM 支持 CSS3 选择器，这很了不起，但不如 xpath 通用； CSS3 不提供在下降到节点后上升的方法。

您可以完成同样的事情，尽管涉及更多:

Mojo::DOM->new($string)
  ->find('result:root > cd > artists > artist.2')
  ->each(sub { say shift->parent->parent->title->text });

或

say $_->parent->parent->title->text
  for Mojo::DOM->new($string)
    ->find('result:root > cd > artists > artist.2')->each;