-  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.