Provided by: librdf-trineshortcuts-perl_0.104-1_all bug

NAME

       RDF::TrineShortcuts - totally unauthorised module for cheats and charlatans

SYNOPSIS

         use RDF::TrineShortcuts;

         my $model = rdf_parse('http://example.com/data.rdf');
         my $query = 'ASK { ?person a <http://xmlns.com/foaf/0.1/Person> . }';
         if (rdf_query($query, $model))
         {
           print "Document describes a person.\n";
         }
         else
         {
           print "Document doesn't describe a person.\n";
           print "What does it describe? Let's see...\n";
           print rdf_string($model);
         }

DESCRIPTION

       This module exports three functions which simplify frequently performed tasks using
       RDF::Trine and RDF::Query. (A number of other functions are also available but not
       exported by default.)

       ·   "rdf_parse($data)"

       ·   "rdf_string($model, $format)"

       ·   "rdf_query($sparql, $endpoint_or_model)"

       In addition, because it calls "use RDF::Trine", "use RDF::Query", and "use
       RDF::Query::Client", your code doesn't need to.

   Main Functions
       "rdf_parse($data)"
           $data can be some serialised RDF (in RDF/XML, Turtle, RDF/JSON, or any other format
           that RDF::Trine::Parser supports); or a URI (string or URI object); or an
           HTTP::Message object; or a hashref (as per RDF::Trine::Model's add_hashref method); or
           a file name or an open file handle; or an RDF::Trine::Iterator::Graph. Essentially it
           could be anything you could reasonably expect to grab RDF from. It can be undef.

           If $input is a blessed object that rdf_parse is unable to natively deal with, it will
           attempt to call "$input->TO_RDF" and deal with the result instead. (This is similar in
           spirit to the JSON module's convert_blessed functionality.)

           The function returns an RDF::Trine::Model.

           There are additional optional named arguments, of which the two most useful are
           probably 'base', which sets the base URI for any relative URI references; and 'type',
           which indicates the media type of the input (though the function can usually guess
           this quite reliably).

             $model = rdf_parse($input,
                                'base' => 'http://example.com/',
                                'type' => 'application/rdf+xml');

           Other named arguments include 'model' to provide an existing RDF::Trine::Model to add
           statements to; and 'context' for providing a context/graph URI (which may be a string,
           URI object or RDF::Trine::Node).

       "rdf_string($model, $format)"
           Serialises an RDF::Trine::Model to a string.

           $model is the model to serialise. If $model is not an RDF::Trine::Model object, then
           it's automatically passed through rdf_parse first.

           $format is the format to use. One of 'RDFXML' (the default), 'RDFJSON', 'Turtle',
           'Canonical NTriples' or 'NTriples'. If $format is not one of the above, then the
           function will try to guess what you meant.

           Preferred namespace names can be provided as a named argument:

            print rdf_string($model, 'turtle',
               namespaces => { foo=>'http://example.com/vocabs/foo#' });

           You can find the relevant Internet media type like this:

            my $type;
            my $string = rdf_string($model, 'rdfxml', media_type=>\$type);
            print $cgi->header($type), $string and exit;

       "rdf_query($sparql, $endpoint)"
           $sparql is a SPARQL query to be run at $endpoint.

           $endpoint may be either an endpoint URI (string or URI object) or a model supported by
           RDF::Query (e.g. an RDF::Trine::Model.)

           Query languages other than SPARQL may be used (see <RDF::Query> for a list of
           supported languages). e.g.

             rdf_query("SELECT ?s, ?p, ?o WHERE (?s, ?p, ?o)"
                       $model,
                       query_lang=>'rdql');

           Options query_base, query_update and query_load_data correspond to the base, update
           and load_data options passed to RDF::Query's constructor.

           If the SPARQL query returns a boolean (i.e. an ASK query), then this function returns
           a boolean. If the query returns a graph (i.e.  CONSTRUCT or DESCRIBE), then this
           function returns an RDF::Trine::Model corresponding to the graph. Otherwise (i.e.
           SELECT) it returns an RDF::Trine::Iterator object.

           For queries which return a graph, an optional $model parameter can be passed
           containing an existing RDF::Trine::Model to add statements to:

             rdf_query("CONSTRUCT {?s ?p ?o} WHERE {?s ?p ?o}",
                       'http://example.com/sparql',
                       model => $model);

           This function can expand a small set of commonly used prefixes. For example:

            $result = rdf_query('SELECT ?id ?name {?id foaf:name ?name}',
                                $model);

           The hashref $RDF::TrineShortcuts::Namespaces is consulted for expansions.

   Additional Functions
       These are not exported by default, so need to be imported explicitly, e.g.

        use RDF::TrineShortcuts qw(:default rdf_node rdf_statement);

       "rdf_node($value, %args)"
           Creates an RDF::Trine::Node object.

           Will attempt to automatically determine whether $value is a blank node, resource,
           literal or variable, but an optional named argument 'type' can be used to explicitly
           indicate this.

           For literals, named arguments 'datatype' and 'lang' are allowed. If 'datatype' is not
           a URI, then it's assumed to be an XSD datatype.

            $node = rdf_node("Hello", type=>'literal', lang=>'en');

           For resources, the named argument 'base' is allowed.

           If $value is undef, then it would normally be treated like a zero-length string. By
           setting the argument 'passthrough_undef' to 1, you can allow it to pass thorugh and
           return undef.

           This function can expand a small set of commonly used prefixes. For example:

            $node = rdf_node('foaf:primaryTopic');

           The hashref $RDF::TrineShortcuts::Namespaces is consulted for expansions.

           This function is not exported by default, but can be exported using the tag ':nodes'
           or ':all'.

            use RDF::TrineShortcuts qw(:default :nodes);

       "rdf_literal($value, %args)", "rdf_blank($value, %args)", "rdf_resource($value, %args)",
       "rdf_variable($value, %args)"
           Shortcuts for rdf_node($value, type=>'literal', %args) and so on. The rdf_resource
           function will create a blank node resource if $value begins '_:'.

           These functions are not exported by default, but can be exported using the tag
           ':nodes' or ':all'.

            use RDF::TrineShortcuts qw(:all);

       "rdf_statement($s, $p, $o, [$g])", "rdf_statement($ntriple, [$g])"
           Returns an RDF::Trine::Statement. Parameters $s, $p, $o and $g can each be either a
           plain string that could be passed to rdf_node, or an arrayref of rdf_node parameters,
           or an RDF::Trine::Node.

           $ntriple is a single N-Triples statement.

           This function is not exported by default, but can be exported using the tag ':all'.

            use RDF::TrineShortcuts qw(:all);

       "flatten_node($node)"
           Converts a node back to a string.

           By default, blank nodes and variables are stringified to their N-Triples and SPARQL
           representations; URIs are stringified without angled bracket delimiters; and literals
           to their literal values.

           Various options are available: 'resource_as', 'blank_as', 'variable_as' and
           'literal_as' can each be set to 'ntriples', 'value' or 'default'.

            print flatten_node($my_resource, resource_as=>'ntriples');

           This function is not exported by default, but can be exported using the tag ':flatten'
           or ':all'.

            use RDF::TrineShortcuts qw(:default :flatten);

       "flatten_iterator($iter)"
           Converts an iterator to a Perl list. In list context returns a list; in scalar context
           returns an arrayref instead.

           Each item in the list is, in the case of a bindings iterator, a hashref; or, in the
           case of a triple/quad iterator, an arrayref [s, p, o, g]. For boolean iterators,
           $iter->get_boolean is returned. The nodes which are values in the hashref/arrayref are
           flattened with flatten_node, unless flatten_iterator is called with 'keep_nodes'=>1.

             my @results = flatten_iterator($iter, keep_nodes=>1);

           You can pass additional options for flatten_node too:

             my @results = flatten_iterator($iter, resource_as=>'ntriples');

           This function is not exported by default, but can be exported using the tag ':flatten'
           or ':all'.

            use RDF::TrineShortcuts qw(:default :flatten);

   Object-Oriented Interface
       RDF::TrineShortcuts has an alternative, object-oriented interface, not enabled by default.

        use RDF::TrineShortcuts -methods;

        my $model = RDF::Trine::Model->temporary_model;

        # Alias for rdf_parse($some_turtle, model=>$model)
        $model->parse($some_turtle);

        # Alias for rdf_string($model, 'rdfxml');
        my $rdfxml = $model->parse('rdfxml');
        print $rdfxml;

        my $query = 'SELECT ?name WHERE { ?id foaf:name ?name . } ';

        # Alias for rdf_query($query, $model);
        my $result = $model->sparql($query);

        # Alias for flatten_iterator();
        my @result = $result->flatten;

       And so on. The following methods are set up:

       ·   RDF::Trine::Model: "parse", "string", "sparql".

       ·   RDF::Trine::Node: "flatten".

       ·   RDF::Trine::Iterator: "flatten".

       ·   URI::http: "sparql".

       ·   URI: "resource".

       Future versions of the RDF::Trine and URI packages may break this. It's a pretty dodgy
       feature.

       You can load the normal RDF::TrineShortcuts function-based interface in addition to the
       object-oriented interface like this:

        use RDF::TrineShortcuts qw(:default -methods);

       Or everything:

        use RDF::TrineShortcuts qw(:all -methods);

BUGS

       Please report any bugs to <http://rt.cpan.org/>.

SEE ALSO

       RDF::Trine, RDF::Query, RDF::Query::Client.

       <http://www.perlrdf.org/>.

       This module is distributed with three command-line RDF tools.  trapper is an RDF
       fetcher/parser/serialiser; toquet is a SPARQL query tool; trist is an RDF statistics tool.

AUTHOR

       Toby Inkster <tobyink@cpan.org>.

COPYRIGHT

       Copyright 2010 Toby Inkster

       This library is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.