handl-lang

The ports — where backends meet the substrate ​

eqsat never imports a backend, and a backend never sees the search. They meet through mlopt_core.ports: a set of Protocol shapes each side implements or consumes. This is the seam the repo split cut along — graphopt's mlopt_torch/mlopt_onnx adapters are implementations of these ports, not parts of the engine.

The contract surfaces ​

  • Source — lifts a domain object (a torch.nn.Module, an ONNX graph) into mlopt_core terms. The substrate sees only terms.
  • Sink — the way back down: lower emits a runnable artifact, verify checks it against the source, executors lists what can run it — all on top of Capabilities's supported_ops/ops, the hard feasibility declaration.
  • Engine — the engine= contract on search: an alternate saturation engine (the PyO3 mlopt_native.NativeEngine). Engines are never auto-detected — an Engine-port value is passed explicitly and stats["engine"] records which ran ("python" reference default, "native" opt-in). The port covers search only — certificates and the non-local passes are Python-engine capabilities.
  • Runner / Executor / ExecutorSpec / Composer — delivery: how a lowered artifact is executed, timed, and chained.
  • Policy — orders the saturation schedule (which rules to try first). Every rule still fires, so the fixed point and the certificate are unchanged — a policy can never decide equivalence.
  • Criterion / CostFn / Strategy / TaskMetric — what "cheapest" means, and the Monolithic/Compositional/Autotuned strategy shapes.
  • The rest of the port vocabulary — Meter, Verifier, VerifyResult, PerformanceModel, Profiler, OpRegistry, RuleSetLike, RuleLike, RuleSetProvider, Binding, TimingResult, signature_conforms.

The boundary honesty ​

The port binds shapes, never contents: DOMAINS, ALL_RULES, MACHINE_SHIPPED rows, and the lawdata tables are data — the registries' names are frozen, the rows are each domain repo's business. Compat re-exports (egraph._term_match, cost._memo_dispatch, …) stay internal even where reachable — "reachable" is not "public".

The frozen names are the substrate slice of the manifest; the domain-side implementations are documented under graphopt.