Symbolic Composer is an interesting tool which tries to apply the principles of programming to the development of musical structures.
This makes it a very complex but powerful tool for music composition. In fact, the developers call it the most sophisticated composing environment currently available on Mac. Symbolic Composer gives you access to advanced mathematical functions that allow you to modify every aspect of your compositions. Symbolic Composer includes MIDI controllers, MIDI channels and over 400 combined tools, fractal generators and more than 300 different scales. The result of this is that it's a very technical application that only serious composers will be able to use. The user guide is extensive but the size of it indicates what a complex application Symbolic Composer is.
Symbolic Composer is an interesting blend of development and musical composition but will only be accessible to professionals.