NAME
   RDF::Closure - pure Perl RDF inferencing

SYNOPSIS
    use RDF::Trine::Iterator qw[sgrep];
    use RDF::Closure qw[iri mk_filter FLT_NONRDF FLT_BORING];

    my $data = iri('http://bloggs.example.com/foaf.rdf');
    my $foaf = iri('http://xmlns.com/foaf/0.1/index.rdf');

    my $model = RDF::Trine::Model->temporary_model;
    my $p     = 'RDF::Trine::Parser';
    $p->parse_url_into_model($data->uri, $model, context => $data->uri);
    $p->parse_url_into_model($foaf->uri, $model, context => $foaf->uri);

    my $cl = RDF::Closure::Engine->new('rdfs', $model);
    $cl->closure;

    my $filter = mk_filter(FLT_NONRDF|FLT_BORING, [$foaf]);
    my $output = &sgrep($filter, $model->as_stream);

    print RDF::Trine::Serializer
      ->new('RDFXML')
      ->serialize_iterator_to_string($output);

DESCRIPTION
   This distribution is a pure Perl RDF inference engine designed as an
   add-in for RDF::Trine. It is largely a port of Ivan Herman's Python
   RDFClosure library, though there has been some restructuing, and there
   are a few extras thrown in.

   Where one of the Perl modules has a direct equivalent in Ivan's library,
   this is noted in the POD.

 Functions
   This package inherits from RDF::Trine and exports the same functions,
   plus:

   *   "mk_filter($basic_filters, $ignore_contexts)"

       Creates a filter (coderef) suitable for use with "sgrep" from
       RDF::Trine::Iterator.

       $basic_filters is an integer which can be assembled by
       bitwise-OR-ing the constants "FLT_NONRDF" and "FLT_BORING".

       $ignore_contexts is an arrayref of RDF::Trine::Node objects, each of
       which represents a context that should be filtered out.

         use RDF::Trine::Iterator qw[sgrep];
         use RDF::Closure qw[iri mk_filter FLT_NONRDF FLT_BORING];

         my $foaf   = iri('http://xmlns.com/foaf/0.1/index.rdf');
         my $filter = mk_filter(FLT_NONRDF|FLT_BORING, [$foaf]);

         my $remaining = &sgrep($filter, $model->as_stream);

         # $remaining is now an iterator which will return all triples
         # from $model except: those in the FOAF named graph, those which
         # are non-RDF (e.g. literal subject) and those which are boring.

       Which triples are boring? Any triple of the form { ?x owl:sameAs ?x
       .}, { ?x owl:equivalentProperty ?x .}, { ?x owl:equivalentClass ?x
       .}, { ?x rdfs:subPropertyOf ?x .} or { ?x rdfs:subClassOf ?x .} is
       boring (i.e. where these statements have the same term in subject
       and object position). Any triple where the subject, predicate and
       object nodes are all in the RDF, RDFS, OWL or XSD namespaces is
       boring. Other triples are not boring.

   For convenience, "RDF::Closure" also exports variables called $RDF,
   $RDFS, $OWL and $XSD which are RDF::Trine::Namespace objects.

SEE ALSO
   RDF::Closure::Engine, RDF::Closure::Model, RDF::Trine::Parser::OwlFn.

   RDF::Trine, RDF::Query.

   <http://www.perlrdf.org/>.

   <http://www.ivan-herman.net/Misc/2008/owlrl/>.

AUTHOR
   Toby Inkster <[email protected]>.

COPYRIGHT
   Copyright 2011-2012 Toby Inkster

   This library is free software; you can redistribute it and/or modify it
   under any of the following licences:

   *   The Artistic License 1.0
       <http://www.perlfoundation.org/artistic_license_1_0>.

   *   The GNU General Public License Version 1
       <http://www.gnu.org/licenses/old-licenses/gpl-1.0.txt>, or (at your
       option) any later version.

   *   The W3C Software Notice and License
       <http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231
       >.

   *   The Clarified Artistic License
       <http://www.ncftp.com/ncftp/doc/LICENSE.txt>.

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.