XML::LibXML::Pattern

XML::LibXML::Pattern(User Contributed Perl DocumentatiXML::LibXML::Pattern(3)



NAME
       XML::LibXML::Pattern - XML::LibXML::Pattern - interface to libxml2
       XPath patterns

SYNOPSIS
	 use XML::LibXML;
	 my $pattern = new XML::LibXML::Pattern(’/x:html/x:body//x:div’, { ’x’ => ’http://www.w3.org/1999/xhtml’ });
	 # test a match on a XML::LibXML::Node $node

	 if ($pattern->matchesNode($node)) { ... }

	 # or on a XML::LibXML::Reader

	 if ($reader->matchesPattern($pattern)) { ... }

	 # or skip reading all nodes that do not match

	 print $reader->nodePath while $reader->nextPatternMatch($pattern);

	 $pattern = XML::LibXML::Pattern->new( pattern, { prefix => namespace_URI, ... } );
	 $bool = $pattern->matchesNode($node);

DESCRIPTION
       This is a perl interface to libxml2’s pattern matching support
       http://xmlsoft.org/html/libxml-pattern.html. This feature requires
       recent versions of libxml2.

       Patterns are a small subset of XPath language, which is limitted to
       (disjunctions of) location paths involving the child and descendant
       axes in abbreviated form as described by the extended BNF given below:

	 Selector ::=	  Path ( ’│’ Path )*
	 Path	  ::=	  (’.//’ │ ’//’ │ ’/’ )? Step ( ’/’ Step )*
	 Step	  ::=	  ’.’ │ NameTest
	 NameTest ::=	  QName │ ’*’ │ NCName ’:’ ’*’

       For readability, whitespace may be used in selector XPath expressions
       even though not explicitly allowed by the grammar: whitespace may be
       freely added within patterns before or after any token, where

	 token	   ::=	   ’.’ │ ’/’ │ ’//’ │ ’│’ │ NameTest

       Note that no predicates or attribute tests are allowed.

       Patterns are particularly useful for stream parsing provided via the
       "XML::LibXML::Reader" interface.

       new()
	     $pattern = XML::LibXML::Pattern->new( pattern, { prefix => namespace_URI, ... } );

	   The constructor of a pattern takes a pattern expression (as
	   described by the BNF grammar above) and an optional HASH reference
	   mapping prefixes to namespace URIs. The method returns a compiled
	   pattern object.

	   Note that if the document has a default namespace, it must still
	   be given an prefix in order to be matched (as demanded by the
	   XPath 1.0 specification). For example, to match an element "<a
	   xmlns="http://foo.bar"</a>", one should use a pattern like this:

	     $pattern = XML::LibXML::Pattern->new( ’foo:a’, { foo => ’http://foo.bar’ });

       matchesNode($node)
	     $bool = $pattern->matchesNode($node);

	   Given a XML::LibXML::Node object, returns a true value if the node
	   matches the compiled pattern expression.

SEE ALSO
       XML::LibXML::Reader for other methods involving compiled patterns.

AUTHORS
       Matt Sergeant, Christian Glahn, Petr Pajas

VERSION
       1.66

COPYRIGHT
       2001-2007, AxKit.com Ltd; 2002-2006 Christian Glahn; 2006-2008 Petr
       Pajas, All rights reserved.



perl v5.8.8			  2008-11-11	      XML::LibXML::Pattern(3)