Hans-Halverson/brimstone: New JavaScript engine written in Rust

Brimstone is a new JavaScript engine built from scratch in Rust that implements over 97% of the ECMAScript specification. It features a bytecode VM inspired by V8's Ignition, a compacting garbage collector, custom RegExp and parser engines, and nearly all builtin objects. The project supports all ES2024 features and stage 4 proposals except SharedArrayBuffer and Atomics. While not production-ready, it can execute JavaScript files and includes comprehensive testing with test262 integration.