XML::LibXML::Pattern(3) 				User Contributed Perl Documentation				   XML::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 is matched by the compiled pattern expression.

SEE ALSO

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

AUTHORS

       Matt Sergeant, Christian Glahn, Petr Pajas

VERSION

       1.70

COPYRIGHT

       2001-2007, AxKit.com Ltd.

       2002-2006, Christian Glahn.

       2006-2009, Petr Pajas.

perl v5.12.1							    2009-10-07						   XML::LibXML::Pattern(3)