Sass reimplemented in rust with nom (very early stage). The "r" in the name might stand for the Rust programming language, or for my name Rasmus.
The sass language is defined in its reference doc. This implementation is incomplete but getting there, if slowly.
Progress:
of 3310 tests passed
(or 1215 of 6065 when claiming to be libsass).
If you want a working rust library for sass right now, you will probably be better of with sass-rs which is a rust wrapper around libsass. Another alternative is sassers which is another early stage pure rust implementation. That said, this implementation has reached a version where I find it usable for my personal projects, and the number of working tests are improving.