# RDF::TRINE::NODE::FORMULA(3PM) - Linux man page online | Library functions

RDF Node class for formulae / graph literals.

Chapter

2013-09-18

**RDF::Trine::Node::Formula(3pm) User Contributed Perl Documentation RDF::Trine::Node::Formula(3pm)**

## NAME

RDF::Trine::Node::Formula - RDF Node class for formulae / graph literals## DESCRIPTION

Formulae are implemented as a subclass of literals. Parts of Trine that have no special knowledge about formulae (e.g. the Turtle serialiser) will just see them as literals with a particular datatype URI (http://open.vocab.org/terms/Formula). If your code needs to detect formulae nodes, try: use Scalar::Util qw[blessed]; if (blessed($node) && $node->isa('RDF::Trine::Node::Formula')) { ... do stuff to formulae ... } or perhaps use Scalar::Util qw[blessed]; if (blessed($node) && $node->can('pattern')) { ... do stuff to formulae ... } Constructor "new ( $pattern )" Returns a new Formula structure. This is a subclass of RDF::Trine::Node::Literal. $pattern is an RDF::Trine::Pattern or a string capable of being parsed with RDF::Trine::Parser::Notation3->parse_formula. Methods "pattern ( $node )" Returns the formula as an RDF::Trine::Pattern. "forAll" Returns the a list of nodes with the @forAll quantifier. This is a fairly obscure bit of N3 semantics. "forSome" Returns the a list of nodes with the @forSome quantifier. This is a fairly obscure bit of N3 semantics. "as_literal_notation" Returns the formula in Notation-3-like syntax, excluding the wrapping "{"..."}". Uses absolute URIs whenever possible, avoiding relative URI references, QNames and keywords. "from_literal_notation ( $string, $base )" Modifies the formula's value using Notation 3 syntax, excluding the wrapping "{"..."}". "equal ( $node )" Returns true if the two nodes are equal, false otherwise. TODO - really need a "not equal, but equivalent" method.## BUGS

Please report any bugs to <http://rt.cpan.org/Dist/Display.html?Queue=RDF-TriN3>.## SEE ALSO

RDF::Trine::Node, RDF::Trine::Pattern.## AUTHOR

Toby Inkster "<@cpan.org>" Based on RDF::Trine::Node::Literal by Gregory Todd Williams.## COPYRIGHT AND LICENCE

Copyright (c) 2006-2010 Gregory Todd Williams. Copyright (c) 2010-2012 Toby Inkster. This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.## DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.**perl v5.18.2 2013-09-18 RDF::Trine::Node::Formula(3pm)**