@mjg59 this is a question of philosophy, I think. Is "be my ideal word processor" adequate source code? If you've got a compiler that can compile that correctly, yes. If you haven't, no. Is the Python source for that word processor adequate source code? I think yes even if you don't have a Python interpreter because you can see how it works, not just that it works. This feels like I'm talking myself into a different position than the one I intuitively thought.