I know of Dyon [1] as an embbedable scripting language written in Rust.

1) https://github.com/PistonDevelopers/dyon

Dyon is built to work really well as a scripting language for the Piston game framework written in Rust. I was just looking at it.

I'll need to compare and see if Gluon can be leveraged in any way.

Rhai [1] and Ketos [2] also exist. I know I have seen one more lisp (which had come further than initial experimentation) but I can't remember what it is called.

1. https://github.com/jonathandturner/rhai 2. https://github.com/murarth/ketos