XML::LibXML::Pattern
Section: User Contributed Perl Documentation (3pm)Updated: 2017-11-10
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NAME
XML::LibXML::Pattern - XML::LibXML::Pattern - interface to libxml2 XPath patternsSYNOPSIS
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 PajasVERSION
2.0128COPYRIGHT
2001-2007, AxKit.com Ltd.2002-2006, Christian Glahn.
LICENSE
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Index
This document was created by man2html, using the manual pages.
Time: 04:45:44 GMT, September 16, 2022
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