There are 2 forked philosophies here.
- Make a pure Processing API. Everything else must be cut off, even though that would be easy cheesy to implement. Like System.out.println() acceptable as println() is a big no-no. :D
- Try to convert everything which is relatively feasible to Processing API. Be it Java, Pyhton, Ruby, etc. Make Processing API running on that environment as complete, comfortable and flexible as possible.