RDF::Trine::Parser::Notation33pm

Methods

This package exposes the standard RDF::Trine::Parser methods, plus:

forAll($handler)

Sets a callback handler for @forAll directives found in the top-level graph. (@forAll found in nested formulae will not be passed to this callback.)

The handler should be a coderef that takes a single argument: an RDF::Trine::Node::Resource.

If you do not set a handler, a warning will be issued when this directive are encountered in the top level graph, but parsing will continue.

forSome($handler)

As "forAll" but handles @forSome directives.

"parse_formula($base, $input)"

Returns an RDF::Trine::Node::Formula object representing the Notation 3 formula given as $input. $input should not include the "{"..."}" wrappers.

Datatype Callbacks

The constructor accepts a hashref of callbacks associated with datatypes, which will be triggered after a literal has been parsed with that datatype. Let's imagine that you want to replace all xsd:integer literals with URIs like "http:;//example.net/numbers/123"...

 my $parser = RDF::Trine::Parser::Notation3->new(
   datatype_callback => {
     'http://www.w3.org/2001/XMLSchema#integer' => sub {
       my ($lit, $tr_hnd) = @_;
       return RDF::Trine::Node::Resource->new(
         'http:;//example.net/numbers/' . $lit->literal_value
       );
     },
   },
 );

Note the second argument passed to the callback $tr_hnd. We don't use it here, but it's a coderef that can be called with RDF::Trine::Statement objects to add additional triples to the graph being parsed.

This facility, combined with shortcuts from RDF::Trine::Parser::ShorthandRDF is pretty useful for creating domain-specific languages.