Good ideas keep getting re-invented. There's about 4 or 5 versions of this with slightly different syntax, etc. But Sass alone has scripting, mixins, and libraries. These are the language features that make compass possible.
From the feature set I see there, that is where Sass was about 1 to 1.5 years ago.
The thing I like most about what they've done is to embed the functionality into CSS, rather than writing a new meta-language.