Nice work!

Let me make a tiny plug for a short Sunday project as well... Brainf*ck in Prolog:

http://github.com/danieldk/brainfuck-pl/

One nice thing is that unit testing is really simple:

http://github.com/danieldk/brainfuck-pl/blob/master/unittest...

And for some very trivial outputs, it can generate the program to create that output.

  ?- brainfuck:interpret([A,B],[],[0],[0],[1,0]).
  A = <,
  B = + ?

Ps. Yes, it's easy to improve generation...