Yea I would imagine they are. I haven't been following the development like I used to, so thanks.
How accurate does the source position information have to be? I don't think the CoffeeScript lexer can output column numbers (at least it didn't last time I checked) and the re-writing stage might give them a little trouble. Should be doable though.
Guess I should head over to github and see how they're doing and start reading the SourceMap spec.