ecma-runtime-cat vs boa-cat vs import_fn

ECMAScript runtime: native built-ins (console, Math, JSON, parseInt, isNaN, ...) that the boa-cat engine exposes to scripts. Each built-in is a NativeFn registered into the initial environment. No mut, no Rc/Arc, no interior mutability, no panics.

Tree-walking ECMAScript interpreter built on ecma-syntax-cat. Evaluates Script programs to Values with a persistent heap and lexical environment, plus native (Rust-implemented) callables for embedder-supplied built-ins. No mut, no Rc/Arc, no interior mutability, no panics, exhaustive matches. Comp-cat-rs reformulation of the Boa engine core, targeting Tauri integration.

Implementation of #[import_fn] macro for Crabzilla