JSON-LD Contexts & Compaction

PurRDF has three explicit JSON-LD/YAML-LD serialization modes:

• expanded preserves the byte-frozen empty-@context representation;
• context compiles a caller prefix map or local JSON-LD 1.1 context once and applies normative compaction;
• derived deterministically assigns neutral ns0, ns1, … aliases solely from absolute IRIs in the dataset. It never invents a vocabulary or infers @vocab.

An RDF dataset does not retain prefix declarations from Turtle, JSON-LD, or another source syntax. Supply them explicitly when those declarations are application policy. All configured surfaces consume the same closed version-1 JSON document and reject duplicate members, unknown fields, invalid contexts, network-only context references, cycles, and resource-limit excesses before emitting output.

{
  "version": 1,
  "mode": "context",
  "prefixes": {
    "ex": "https://example.org/",
    "schema": "https://schema.org/"
  },
  "yaml_schema_url": "https://example.org/purrdf.schema.json"
}

Rust

use purrdf::{
    JsonLdSerializeOptions, parse_dataset,
    serialize_dataset_to_jsonld_with_options,
};

let dataset = parse_dataset(
    b"<https://example.org/alice> <https://schema.org/name> \"Alice\" .",
    "application/n-triples",
    None,
)?;
let options = JsonLdSerializeOptions::prefixes([
    ("ex", "https://example.org/"),
    ("schema", "https://schema.org/"),
])?;
let jsonld = serialize_dataset_to_jsonld_with_options(&dataset, &options)?;
Ok::<(), purrdf::RdfDiagnostic>(())

Keep a CompiledJsonLdContext (or JsonLdSerializeOptions::compiled) when the same application context is used for many datasets. JsonLdContextRegistry resolves context IRIs and @import only from caller-supplied immutable local documents; PurRDF never performs network context loading.

CLI

Write the versioned document to a file, then pass it to any RDF-producing CLI path:

purrdf --jsonld-options context.json convert --from turtle --to jsonld input.ttl output.jsonld

The option is rejected for non-JSON-LD/YAML-LD output, canonical output, non-graph SPARQL results, and carrier projections rather than being ignored.

Python

import json
import purrdf

options = json.dumps({
    "version": 1,
    "mode": "context",
    "prefixes": {"ex": "https://example.org/"},
})
context = purrdf.CompiledJsonLdContext(options)
text = purrdf.serialize_jsonld(
    nquads,
    format=purrdf.RdfFormat.N_QUADS,
    output_format="jsonld",
    context=context,
)

Store.dump, MutableDataset.dump, immutable RdfDataset, and the RDFLib compatibility Graph.serialize surface accept the same configuration. Prefixes explicitly bound on a compatibility graph become its caller context.

JavaScript and WebAssembly

const options = JSON.stringify({
  version: 1,
  mode: "context",
  prefixes: { ex: "https://example.org/" },
});
const context = new CompiledJsonLdContext(options);
const text = dataset.serializeWithContext("jsonld", context);

Use serializeConfigured for one-shot requests. QueryEngine exposes matching configured methods for CONSTRUCT and DESCRIBE graph results, and the playground worker accepts the same options document on its serialization path.

C

Compile options with purrdf_jsonld_context_compile, reuse the returned PurrdfJsonLdContext with purrdf_serialize_jsonld_configured, then release it with purrdf_jsonld_context_free. The serializer accepts exactly one options byte slice or compiled handle. Buffers and errors retain the normal libpurrdf ownership rules.

YAML-LD uses the same context lens. Its optional schema URL changes only the deterministic YAML language-server header; it does not change RDF semantics.