Matcher reference

Each capability in the engine's registry has one section in this reference. The table is generated from the registry at build time; each name links to its section.

An assertion answers passed, failed or refused, under either polarity. A query reports what the engine measured and accepts positive polarity only. Reads faces means the claim measures BRep faces or edges, so a STEP subject whose faces carry no surface refuses it.

How to read a section

Every section has the same parts:

• Signature: the TypeScript method on expectGeo(subject), or the query the assertion client sends.
• Payload: the fields, their defaults, and the wire payload processRequest receives.
• Admitted geometry: which subjects the engine measures, and what it refuses.
• Refusal codes: the diagnostic codes of a refused result, and the code of a failed one.
• Examples: one claim that passes and one the engine refuses, in TypeScript and in Python.

The examples name their subject in a comment. Each was run against the WASM build of geospec-engine, and the comment records the status it returned.

Shared payload rules

• Units. Lengths are millimetres, areas mm², volumes mm³, in the z-up frame the subject was admitted in.
• Tolerance. Where a section lists tolerance, equality is abs(measured - expected) <= tolerance. The default is 0.02 mm unless the section says otherwise.
• Numeric expectation. A number, or an object with any of value, greaterThan, greaterThanOrEqual, lessThan and lessThanOrEqual. Tolerance applies to value only; the four comparisons are strict as written.
• Points. A [x, y, z] triple, or an object with any of x, y and z to constrain only those axes.
• Selectors. A component or occurrence name is an exact string, or a regular expression. On the wire a regular expression is { type: 'regexp', pattern, flags }.
• Unknown fields. A payload with an unknown or malformed field is not evaluated. processRequest throws a ProtocolError with code invalid-claim.

Common refusals

These apply to every section, so the sections do not repeat them:

• MATCHER_TIMEOUT: the claim used up its workUnitBudget and was abandoned. The engine's default budget is 8,000,000 work units.
• GEOSPEC_EVIDENCE_UNSUPPORTED on a capability that reads faces, when the STEP subject's faces carry no surface (tessellated-only product geometry).
• GEOSPEC_UNSUPPORTED_EVIDENCE on a STEP subject admitted in a y-up frame: such a subject answers minimumDistance only.
• GEOSPEC_BACKEND_FAILED: the geometry backend could not complete the measurement.

A refusal is never a pass, and negating a claim does not turn a refusal into a pass. Read a refusal covers what to change.