Module cel 

CEL (Common Expression Language) engine (DW-058).

This module provides a thin wrapper around the cel-interpreter crate, offering:

• CelProgram — a compiled CEL program (parse + type-check done at compile time, never on the request path).
• CelContext — a CEL evaluation context (variable bindings).
• CelValue — a CEL value (the result of evaluation).

Design (decision 5; §9.3)

CEL expressions are compiled once at config publish time and embedded in the snapshot as CelProgram instances. The request path only evaluates — it never parses or compiles. This keeps the hot path fast (the cel-interpreter’s tree-walking evaluator is ~100-500 ns/op for simple expressions, measured by the benchmark in benches/micro.rs).

AOT vs JIT

The issue scope mentions “cranelift JIT optional”. The current implementation uses the cel-interpreter’s tree-walking evaluator (no JIT). If the benchmark shows this is too slow for a given use case, a cranelift JIT backend can be added behind a feature flag without changing the API — CelProgram would hold either an AST or JIT-compiled code, and CelProgram::evaluate would dispatch accordingly.

Feature gate

The cel cargo feature must be enabled. Without it, the module is not compiled and config fields that reference CEL expressions are accepted but inert.

Modules

everywhere

CEL everywhere (DW-059).

jit

CEL JIT compilation via cranelift (PERF-09, #260).

Structs

CelContext

A CEL evaluation context — variable bindings for evaluation.

CelProgram

A compiled CEL program.

ParseError

ParseErrors

Enums

ExecutionError

Value

Functions

value_to_bool

Convert a CEL Value to a Rust bool, if possible.

value_to_float

Convert a CEL Value to a Rust f64, if possible.

value_to_int

Convert a CEL Value to a Rust i64, if possible.

value_to_string

Convert a CEL Value to a Rust string, if possible.

Type Aliases

CelResult

The result of evaluating a CEL expression.