I went to this last summer, and it was pretty awesome. I did stuff in Clojure using Overtone; everyone else used a dialect of Common Lisp to generate MIDI files. I took off on this Overtone tangent because I had prior programming experience and a lot of curiousity about Clojure; most of the other people there were musicians, not programmers.
btw, these musicians were writing fairly sophisticated software in Lisp within two weeks of first being introduced to programming at all. :-)
You can see my own code from that experience here:
Caveat: my Clojure's a bit rough, and not properly idiomatic.
Another, very unfortunate caveat: there was an extremely inappropriate remark from Dr. Cope which, in my opinion, alienated a pair of Indian programmers, the only people there with any programming experience at all, other than myself. After Dr. Cope made this remark, both of them were gone the next day.
Also, I have to say, Emily Howell is mostly a probabilistic beat-slicer which works against sheet music. Like almost all artificial intelligence, as far as I can tell, she is much more artificial than intelligent. Her previous incarnation, iirc, only sliced up Bach measures into new measures, although this had the interesting side effect of re-creating several measures of Mozart, who apparently was a huge Bach fan.
Oh also - I'm pretty sure Cope put a ton of source code in one of his books. You can find them on Amazon and use "search inside" to find out which books have code. Be prepared for a little heavy lifting, though, if you're not familiar with Lisp.