NAME

RDF::aREF::Encoder - encode RDF to another RDF Encoding Form

SYNOPSIS

use RDF::aREF::Encoder;
my $encoder = RDF::aREF::Encoder->new;

my $qname  = $encoder->qname('http://schema.org/Review'); # 'schema_Review'

my $predicate = $encoder->predicate(
    'http://www.w3.org/1999/02/22-rdf-syntax-ns#type'
); # 'a'

my $object = $encoder->object({
    type  => 'literal',
    value => 'hello, world!',
    lang  => 'en'
}); # 'hello, world!@en'

# method also accepts RDF::Trine::Node instances
my $object = $encoder->object( RDF::Trine::Resource->new($iri) );

DESCRIPTION

This module provides methods to encode RDF data in another RDF Encoding Form (aREF). As aREF was designed to facilitate creation of RDF data, it may be easier to create aREF "by hand" instead of using this module!

OPTIONS

ns

A default namespace map, given as version string of module RDF::NS for stable qNames or as instance of RDF::NS. The most recent installed version of RDF::NS is used by default. The value 0 can be used to only use required namespace mappings (rdf, rdfs, owl and xsd).

METHODS

Note that no syntax checking is applied, e.g. whether a given URI is a valid URI or whether a given language is a valid language tag.

qname( $uri )

Abbreviate an URI as qName or return undef. For instance http://purl.org/dc/terms/title is abbreviated to "dct_title".

uri( $uri )

Abbreviate an URI or as qName or enclose it in angular brackets.

predicate( $uri )

Return an predicate URI as qNamem, as "a", or as given URI.

literal( $value, $language_tag, $datatype_uri )

Encode a literal RDF node by either appending "@" and an optional language tag, or "^" and an datatype URI.

bnode( $identifier )

Encode a blank node by prepending "_:" to its identifier.

object( $object )

Encode an RDF object given either as hash reference as defined in RDF/JSON format (see also method as_hashref of RDF::Trine::Iterator::Graph), or in array reference as internally used by RDF::Trine.

A hash reference is expected to have the following fields:

type

one of uri, literal or bnode (required)

value

the URI of the object, its lexical value or a blank node label depending on whether the object is a uri, literal or bnode

lang

the language of a literal value (optional but if supplied it must not be empty)

datatype

the datatype URI of the literal value (optional)

An array reference is expected to consists of

• three elements (value, language tag, and datatype uri) for literal nodes,

• two elements "URI" and the URI for URI nodes,

• two elements "BLANK" and the blank node identifier for blank nodes.

SEE ALSO

RDF::aREF::Decoder, RDF::Trine::Node