RDF is useful for exchanging graph data. ISO Prolog is useful for writing rules and asking questions about it. They can be used together with a small converter.
RDF input
| rdf-to-prolog
v
rdf/4 facts + your Prolog rules
| run a query and write ground rdf/4 results
v
Prolog result facts
| prolog-to-rdf
v
RDF output
RDF contributes identifiers, literals, blank nodes, and graphs. Prolog contributes terms, unification, rules, recursion, and search. The connection is simply a choice of Prolog terms for RDF values, documented in the mapping guide.
This package performs the conversions. EyeProlog or another Prolog engine runs the rules. You can inspect the intermediate facts, use ordinary Prolog tools, and convert the results back to RDF.
The examples call their result query result_rdf/4. The converter reads valid,
ground rdf/4 facts, and also result_rdf/4 facts, so a listing of that
query’s answers converts directly.
The rules determine what is inferred. Converting RDF into facts does not automatically give a Prolog program RDF entailment semantics, and negation-as-failure does not turn missing RDF statements into false ones. Literal spelling and blank-node identity also need to be respected when writing rules.
The useful pieces are the converters, the documented mapping, and the examples you can run. RDF and ISO Prolog provide the existing foundations.