@usine/expression

Typed CEL checking and evaluation for usine. Callers describe object types and root variables with Environment, then use ExpressionEngine to check boolean trigger expressions, check scalar prompt expressions, or evaluate either form over plain JSON.

Unknown variables and object paths fail during checking, including paths inside CEL macros such as exists. Failures are typed values: ExpressionCheckError from parsing, type checking, or result-type checking, ExpressionEvaluationError from evaluation, and the ExpressionError union covering both. JSON integers declared as CEL int or uint are converted to bigint before evaluation so GraphQL payloads keep CEL integer semantics.

relatedStringLiterals(source, memberPath) reports string literals from the smallest expression subtrees that use a member path. Config validation uses it to diagnose undeclared GitHub labels without coupling @usine/config to the CEL adapter's AST.

MarcbachmannCelLayer uses @marcbachmann/[email protected]. The exported ExpressionEngine contract contains CEL type names and usine-owned descriptors rather than library objects; an @bufbuild/cel adapter can provide the same service tag without changing callers.

All APIs remain 0.x and can change between minor releases.

Import ExpressionEngine, Source, Environment, the environment descriptors, Scalar, and the typed expression errors from @usine/expression/expression-engine. This entry point replaces @usine/expression/model; existing imports from that subpath must use /expression-engine. Import the CEL adapter layer separately from @usine/expression/marcbachmann-cel.