CEL-Core: High-level API for the Common Expression Language

This crate provides a unified Env for working with CEL expressions, following the cel-go architecture pattern.

Quick Start

use cel_core::Env;
use cel_core::CelType;

// Create an environment with standard library and a variable
let env = Env::with_standard_library()
    .with_variable("x", CelType::Int);

// Parse and type-check in one step
let ast = env.compile("x + 1").unwrap();
assert!(ast.is_checked());

Architecture

The Env struct coordinates:

• Parser: Converts source text into an AST
• Checker: Type-checks expressions and resolves references
• Variables: User-defined variable declarations
• Functions: Standard library + custom function declarations

Modules

• types: Core type system, AST, and declarations
• parser: Lexer, parser, and macro expansion
• checker: Type checking and overload resolution
• ext: Extension libraries (strings, math, encoders, optionals)

Proto Conversion

For proto wire format conversion (interop with cel-go, cel-cpp), use the cel-core-proto crate which provides CheckedExpr and ParsedExpr types.