XML :: LibXML的文本节点父级的概念 [英] XML::LibXML's notion of a text node's parent

问题描述

这里有些奇怪.

在下面的示例中，我正在通过XPath查询(//book/isbn/text())访问文本节点. text()是强制使XML::LibXML允许我使用XML::LibXML::Text方法的必要条件.

In the example below, I'm accessing text nodes via an XPath query ( //book/isbn/text() ). The text() is necessary to coerce XML::LibXML into allowing me to use the XML::LibXML::Text methods.

但是，要到达父节点，我必须调用两次parentNode方法以获得真正的父节点(在本例中为<book>):

To get to the parent node though, I have to invoke the parentNode method twice to get the true parent node (<book> in this case):

use strict;
use warnings;
use XML::LibXML;

my $xml = XML::LibXML->new->parse_string( << 'MAIN' );
  <library>
    <book>
      <title>Perl Best Practices</title>
      <author>Damian Conway</author>
      <isbn>0596001738</isbn>
      <pages>542</pages>
      <image src="http://www.oreilly.com/catalog/covers/perlbp.s.gif"
             width="145" height="190" />
    </book>
    <book>
      <title>Perl Cookbook, Second Edition</title>
      <author>Tom Christiansen</author>
      <author>Nathan Torkington</author>
      <isbn>0596003137</isbn>
      <pages>964</pages>
      <image src="http://www.oreilly.com/catalog/covers/perlckbk2.s.gif"
             width="145" height="190" />
    </book>
  </library>
MAIN

foreach my $isbn ( $xml->findnodes( '//book/isbn/text()' ) ) {

    # Do something with $isbn->setData()

    my $book = $isbn->parentNode->parentNode;  # My daddy's daddy is my daddy?
    print $book->toString;
}

输出

<book>
      <title>Perl Best Practices</title>
      <author>Damian Conway</author>
      <isbn>0596001738</isbn>
      <pages>542</pages>
      <image src="http://www.oreilly.com/catalog/covers/perlbp.s.gif" width="145" height="190"/>
    </book><book>
      <title>Perl Cookbook, Second Edition</title>
      <author>Tom Christiansen</author>
      <author>Nathan Torkington</author>
      <isbn>0596003137</isbn>
      <pages>964</pages>
      <image src="http://www.oreilly.com/catalog/covers/perlckbk2.s.gif" width="145" height="190"/>
    </book>

---

所以:

---

So:

• 在假设//isbn和//isbn/text()是同一节点时，我对XML节点的理解是错误的，或者
• 这是 XML::LibXML 的parentNode方法中的错误吗? ?

• is my understanding of XML nodes incorrect in assuming that //isbn and //isbn/text() are the same node, or
• is this a bug in XML::LibXML's parentNode method?

推荐答案

XML文档中的每个元素都是一个节点.如果该元素包含文本(例如<isbn>019328373476</isbn>)，则它是该元素的子节点(与元素相对的文本类型).

Each element in a XML document is a node. If that element contains text (e.g. <isbn>019328373476</isbn>), then it is a child node (of type text, as opposed to element) of that element.

这不是XML :: LibXML的parentNode方法中的错误.

It is not a bug in XML::LibXML's parentNode method.

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