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


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
       2.0210

COPYRIGHT
       2001-2007, AxKit.com Ltd.

       2002-2006, Christian Glahn.

       2006-2009, Petr Pajas.

LICENSE
       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

perl v5.40.0                      2024-09-01           XML::LibXML::Pattern(3)