XML::LibXML::Pattern − XML::LibXML::Pattern − interface to libxml2 XPath patterns
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);
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.
XML::LibXML::Reader for other methods involving compiled patterns.
Matt Sergeant, Christian Glahn, Petr Pajas
2.0209
2001−2007, AxKit.com Ltd.
2002−2006, Christian Glahn.
2006−2009, Petr Pajas.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.