Javascript seems like a great contender in this space to me. Btw, as well as using nodejs / v8, there are also Rust bindings for SpiderMonkey (Mozilla's JS engi

Javascript seems like a great contender in this space to me. Btw, as well as using nodejs / v8, there are also Rust bindings for SpiderMonkey (Mozilla's JS engine): https://github.com/servo/rust-mozjs https://github.com/servo/rust-mozjs (not super user-friendly yet, as this mainly exists for Servo - but there's enough here to embed Javascript scripts in your Rust projects!)