Mac-compatible Csound editor available for free, with open source code.
One thing to keep in mind, however, is that QuteCsound has been found to be quite unstable on OS X when Csound is used threaded. If this is a concern for you, it may be worth exploring other options. But if you're looking for a solid and user-friendly Csound editor that can help streamline your workflow, give QuteCsound a try!
Version 0.4.1: N/A