NAME

RDFStore::Literal - An RDF Literal Node implementation

SYNOPSIS

        use RDFStore::Literal;
        my $literal = new RDFStore::Literal('Tim Berners-Lee');
        my $literal1 = new RDFStore::Literal('Today is a sunny day, again :)');

        print $literal->toString." is ";
        print "not"
                unless $literal->equals($literal1);
        print " equal to ".$literal1->toString."\n";
 

DESCRIPTION

An RDF Literal Node implementation using Storable(3). A Literal object can either contain plain (utf8) strings. Such an implementation allows to create really generic RDF statements about Perl data-structures or objects for example. Generally an RDFStore::Literal can be thought like an atomic perl scalar. XML well-formed literal values are supported simply by storing the resulting utf8 bytes into a perl scalar; none methods are being provided tomanage literals as XML (e.g. SAX2 events and stuff like that)

METHODS

new ( LITERAL )

This is a class method, the constructor for RDFStore::Literal. The only parameter passed is either a plain perl scalar (LITERAL)

getParseType

Return the parseType of the RDF Literal; possible values are Literal or Resource (default).

getLang

Return the language of the RDF Literal eventually coming from xml:lang attribute on parsing.

getDataType

Return the RDFStore::Resource representing the XMLSchema data type of the RDF Literal.

getLabel

Return the literal text of the node.

getDigest

Return a Cryptographic Digest (SHA-1 by default) of the RDF Literal; the actual digest message is guranteed to be different for URI representing RDF Resources or RDF Literals.

equals

Compare two literals.

SEE ALSO

RDFStore::RDFNode(3)

ABOUT RDF

 http://www.w3.org/TR/rdf-primer/

 http://www.w3.org/TR/rdf-mt

 http://www.w3.org/TR/rdf-syntax-grammar/

 http://www.w3.org/TR/rdf-schema/

 http://www.w3.org/TR/1999/REC-rdf-syntax-19990222 (obsolete)

BUGS

The language of the literal as recently specified by the RDF Core WG is not supported and the typed literals are not implemented; the latter is due mainly because perl is an untyped language and perhaps such data-typing abstractions should fit in a higher level application specific API.

AUTHOR

        Alberto Reggiori <areggiori@webweaving.org>