RDF 1.2 Features

PurRDF is RDF 1.2-first: the features RDF 1.2 Concepts adds over RDF 1.1 are part of the core data model, carried through the IR, the codecs, SPARQL, validation, the language bindings, and the GTS transport.

Triple terms

RDF 1.2 lets a triple itself be a term in object position — the “quoted triple” of RDF-star, written <<( s p o )>> in SPARQL 1.2 syntax. In the IR a triple term is interned like any other term and gets a TermId, so it composes with everything else (patterns, results, serialization).

• The star-capable codecs (Turtle, TriG, N-Triples, N-Quads, JSON-LD star) round-trip triple terms; see Codecs & Determinism for what happens on a star-incapable projection.
• SPARQL 1.2 quoted-triple syntax is parsed by purrdf-sparql-algebra and evaluated natively — the W3C SPARQL 1.2 triple-term surface passes in the conformance harness (Conformance & Testing).
• In JavaScript, DataFactory.quotedTriple(...) produces the same term (RDF/JS in JavaScript).

Reifiers and annotations

RDF 1.2 replaces old-style reification with reifiers: terms that name an occurrence of a triple (rdf:reifies), so you can attach metadata to a statement without asserting anything odd. In PurRDF, reifier bindings and annotations live in dedicated side-tables on the dataset rather than being smeared into the quad table.

Reifier bindings and annotations survive every star-capable codec round-trip; projections into star-incapable formats drop them loudly, with the realized count handed to the loss ledger (see Slices, Mappings & Provenance). SHACL support for validating reified statements — the draft sh:reifierShape / sh:reificationRequired surface — is covered in SHACL.

Base-direction literals

RDF 1.2 adds rdf:dirLangString: a language-tagged literal that also carries a base direction (ltr or rtl) for correct bidirectional-text handling. These are first-class in the IR and in every binding:

const rtl = f.directionalLiteral("مرحبا", "ar", "rtl");

Directions survive serialization round-trips through the star-capable codecs — the JavaScript quickstart demonstrates the N-Quads round-trip.

RDF 1.2 is a complete target, not a draft excuse

PurRDF treats the RDF 1.2 / SPARQL 1.2 specifications as a complete, implementable target. Where a feature is scoped (for example, the SHACL 1.2 reifier-shape support is a scoped Working Draft feature, not full SHACL 1.2 conformance), the scope is stated explicitly and gated by tests — never left as a silent partial implementation. The live per-feature status is the conformance matrix in docs/CONFORMANCE.md.

Where each feature shows up

The GTS mapping of triple terms and rdf:reifies is formalized in the GTS specification, which pins its RDF 1.2 substrate to the 07 April 2026 W3C Candidate Recommendation Snapshot.