Concepts

Architecture, design rationale, and contributor deep-dives. Audience: contributors, curious users wondering “why is it built this way,” embedders trying to predict behavior.

For day-to-day usage see the Python guide or Rust guide.

Architecture + design

• Architecture — layered diagram, the petgraph storage, indexes, the query pipeline.

• Design decisions — the label model, why Cypher over SQL, transaction model.

• Multi-label rationale — why KGLite uses an immutable primary type plus optional secondary labels.

• Cypher conformance — what subset of Cypher kglite supports + three-valued logic + the conformance harness.

• Concurrency — direct graph ownership, shared sessions, optimistic commits, snapshots, and disk-backed generation semantics.

• Generated project facts — workspace, package, CI, storage, format, and benchmark facts derived from source.

Extending

• Adding a storage backend — trait surface + the in-memory / mapped / disk patterns.

• Adding a query language — Cypher and the fluent API are peers under languages/; the same shape works for SPARQL or a custom DSL.