XML::LibXML::Pattern(3pm) User Contributed Perl Documentation XML::LibXML::Pattern(3pm)
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
2.0134
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 v5.34.0 2022-02-11 XML::LibXML::Pattern(3pm)
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