Varve.Rdf 0.1.0-preview.20

Varve.Rdf

The RDF 1.1 and 1.2 term model, the abstract quad source contract, and RDF Dataset Canonicalization (RDFC-1.0).

• Two representations. RdfTermView is a zero-allocation window over a parser's buffer, valid for the callback that receives it. RdfTerm is the owned term, produced only when someone asks — because allocation per quad is a defect, not a trade-off.

• RDF 1.2 from the start: triple terms, and language-tagged strings with a base direction.

• Term equality, permanently. Character by character over lexical form, datatype IRI and language tag (Concepts §3.3). "1"^^xsd:integer and "01"^^xsd:integer are different terms and stay different terms; value comparison belongs to a SPARQL evaluator, not to a graph.

• RDFC-1.0 over any quad source: the canonical N-Quads form and the issued blank node identifiers, SHA-256 or SHA-384, bounded by a work limit that fails explicitly on a poison graph instead of running without end.

• IQuadSource is the contract everything reads through: an opaque 64-bit handle, internalise and externalise, an equality comparer supplied by the source, and four explicit graph modes — the default graph, one named graph, every named graph (SPARQL's GRAPH ?g), or the union. Two members for an optimiser: a cardinality estimate per pattern that is exact, estimated or honestly unknown, and an inline-value accessor that hands over the integer or boolean a handle encodes in its own bits without materialising the term.

• QuadOverlay and QuadDelta: a source with a change applied, (B \ R) ∪ A, merged at scan time. One implementation serves a store's as-of reads and the view a pre-commit validator gets.

• GraphScope, GraphScopedQuadSource and CallerScope (ADR 0107): a set of graphs — every graph, or the default graph and named graphs by IRI or by IRI prefix — and a source seen through one, which filters every Match, Contains and Estimate by graph so that a graph outside the scope is unobservable. CallerScope is what a host resolves for one caller on one dataset: a readable scope, a writable scope, and whether it administers the dataset. GraphNotWritableException is the refusal a write outside the writable scope raises.

InMemoryDataset dataset = new();
dataset.Add(RdfTerm.Iri("http://example.org/s"u8), RdfTerm.Iri("http://example.org/p"u8),
            RdfTerm.Literal("chat"u8, "en-GB"u8));

using IQuadCursor cursor = dataset.Match(
    TermHandle.None, TermHandle.None, TermHandle.None, GraphPattern.DefaultGraph);

Layer 1 of Varve, a .NET-native event-sourced RDF store and SPARQL toolkit. MPL-2.0.