115 lines
2.9 KiB
Plaintext
115 lines
2.9 KiB
Plaintext
=head1 NAME
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XML::LibXML::Pattern - XML::LibXML::Pattern - interface to libxml2 XPath patterns
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=head1 SYNOPSIS
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use XML::LibXML;
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my $pattern = XML::LibXML::Pattern->new('/x:html/x:body//x:div', { 'x' => 'http://www.w3.org/1999/xhtml' });
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# test a match on an XML::LibXML::Node $node
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if ($pattern->matchesNode($node)) { ... }
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# or on an XML::LibXML::Reader
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if ($reader->matchesPattern($pattern)) { ... }
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# or skip reading all nodes that do not match
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print $reader->nodePath while $reader->nextPatternMatch($pattern);
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$pattern = XML::LibXML::Pattern->new( pattern, { prefix => namespace_URI, ... } );
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$bool = $pattern->matchesNode($node);
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=head1 DESCRIPTION
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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.
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Patterns are a small subset of XPath language, which is limited to
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(disjunctions of) location paths involving the child and descendant axes in
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abbreviated form as described by the extended BNF given below:
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Selector ::= Path ( '|' Path )*
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Path ::= ('.//' | '//' | '/' )? Step ( '/' Step )*
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Step ::= '.' | NameTest
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NameTest ::= QName | '*' | NCName ':' '*'
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For readability, whitespace may be used in selector XPath expressions even
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though not explicitly allowed by the grammar: whitespace may be freely added
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within patterns before or after any token, where
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token ::= '.' | '/' | '//' | '|' | NameTest
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Note that no predicates or attribute tests are allowed.
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Patterns are particularly useful for stream parsing provided via the C<<<<<< XML::LibXML::Reader >>>>>> interface.
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=over 4
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=item new()
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$pattern = XML::LibXML::Pattern->new( pattern, { prefix => namespace_URI, ... } );
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The constructor of a pattern takes a pattern expression (as described by the
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BNF grammar above) and an optional HASH reference mapping prefixes to namespace
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URIs. The method returns a compiled pattern object.
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Note that if the document has a default namespace, it must still be given an
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prefix in order to be matched (as demanded by the XPath 1.0 specification). For
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example, to match an element C<<<<<< E<lt>a xmlns="http://foo.bar"E<lt>/aE<gt> >>>>>>, one should use a pattern like this:
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$pattern = XML::LibXML::Pattern->new( 'foo:a', { foo => 'http://foo.bar' });
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=item matchesNode($node)
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$bool = $pattern->matchesNode($node);
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Given an XML::LibXML::Node object, returns a true value if the node is matched
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by the compiled pattern expression.
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=back
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=head1 SEE ALSO
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L<<<<<< XML::LibXML::Reader >>>>>> for other methods involving compiled patterns.
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=head1 AUTHORS
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Matt Sergeant,
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Christian Glahn,
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Petr Pajas
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=head1 VERSION
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2.0134
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=head1 COPYRIGHT
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2001-2007, AxKit.com Ltd.
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2002-2006, Christian Glahn.
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2006-2009, Petr Pajas.
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=cut
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=head1 LICENSE
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This program is free software; you can redistribute it and/or modify it under
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the same terms as Perl itself.
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