Guide
How the library is layered, how to author a rule, and how the MMS/convergence/conformance machinery pins every entry's behavior.
Start with the layering to understand how grid, stencil, rule, and problem files compose; then authoring a rule for the contributor walkthrough, MMS and convergence for how correctness and order-of-accuracy claims are tested, and conformance for the cross-language suite that keeps every ESS binding byte-identical.
- Authoring a rule
Walkthrough: grid file → stencil → BC rule → lint → fixtures → goldens, per the AGENTS.md contract.
- Conformance
The ast/simulation/convergence categories, the single-pathway doctrine, and how the runners work across the five ESS bindings.
- MMS and convergence
How inline §6.6.5 tests, convergence manifests, and committed goldens pin correctness and observed order of accuracy.
- The layering
The compositional design: grid → stencil → rule → problem, held together by template imports and load-time metaparameters.