rdf.pl -- RDF/XML parser

This module parses RDF/XML documents. It defines two processing modes: load_rdf/2 and load_rdf/3 which process a document into a list of rdf(S,P,O) terms and process_rdf/3 which processes the input description-by-description and uses a callback to handle the triples.

To be done

- The predicate load_rdf/2,3 is too easily confused with the semweb library predicate rdf_load/2,3 which uses process_rdf/3 to store the triples in the triple DB.

- It would be better to use library(intercept) do distinguish to have one predicate that can operate in both collecting and streaming modes.

 load_rdf(+File, -Triples) is det

 load_rdf(+File, -Triples, :Options) is det

Parse an XML file holding an RDF term into a list of RDF triples. see rdf_triple.pl for a definition of the output format. Options:

base_uri(+URI)

URI to use as base

expand_foreach(+Bool)

Apply each(Container, Pred, Object) on the members of Container

namespaces(-Namespaces:list(NS=URL))

Return list of namespaces declared using xmlns:NS=URL in the document. This can be used to update the namespace list with rdf_register_ns/2.

See also

- Use process_rdf/3 for processing large documents in call-back style.

 xml_to_rdf(+XML, -Triples, +Options)

 process_rdf(+Input, :OnObject, :Options)

Process RDF from Input. Input is either an atom or a term of the format stream(Handle). For each encountered description, call OnObject(+Triples) to handle the triples resulting from the description. Defined Options are:

base_uri(+URI)

Determines the reference URI.

db(DB)

When loading from a stream, the source is taken from this option or -if non-existent- from base_uri.

lang(LanguageID)

Set initial language (as xml:lang)

convert_typed_literal(:Convertor)

Call Convertor(+Type, +Content, -RDFObject) to create a triple rdf(S, P, RDFObject) instead of rdf(S, P, literal(type(Type, Content)).

namespaces(-Namespaces:list(NS=URL))

Return list of namespaces declared using xmlns:NS=URL in the document. This can be used to update the namespace list with rdf_register_ns/2.

entity(Name, Value)

Overrule entity values found in the file

embedded(Boolean)

If true, do not give warnings if rdf:RDF is embedded in other XML data.

 on_xmlns(+NS, +URL, +Parser)[private]

Build up the list of encountered xmlns:NS=URL declarations. We use destructive assignment here as an alternative to assert/retract, ensuring thread-safety and better performance.

Undocumented predicates

The following predicates are exported, but not or incorrectly documented.

 load_rdf(Arg1, Arg2, Arg3)