JezK
Edit File: Pattern.pod
=head1 NAME XML::LibXML::Pattern - XML::LibXML::Pattern - interface to libxml2 XPath patterns =head1 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); =head1 DESCRIPTION This is a perl interface to libxml2's pattern matching support I<<<<<< 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 C<<<<<< XML::LibXML::Reader >>>>>> interface. =over 4 =item 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 C<<<<<< E<lt>a xmlns="http://foo.bar"E<lt>/aE<gt> >>>>>>, one should use a pattern like this: $pattern = XML::LibXML::Pattern->new( 'foo:a', { foo => 'http://foo.bar' }); =item matchesNode($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. =back =head1 SEE ALSO L<<<<<< XML::LibXML::Reader >>>>>> for other methods involving compiled patterns. =head1 AUTHORS Matt Sergeant, Christian Glahn, Petr Pajas =head1 VERSION 2.0134 =head1 COPYRIGHT 2001-2007, AxKit.com Ltd. 2002-2006, Christian Glahn. 2006-2009, Petr Pajas. =cut =head1 LICENSE This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.