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

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

         # or on an 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 limited 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 an 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
       1.88

COPYRIGHT
       2001-2007, AxKit.com Ltd.

       2002-2006, Christian Glahn.

       2006-2009, Petr Pajas.



perl v5.12.5                                     2011-09-21                          XML::LibXML::Pattern(3)