Aftermath

I can't believe how easily I implemented the other math operators. Sure a few rough edges are expected to manifest, but still, everything in the "a few operators" post is implemented. I'm now in the "after" of math operators.

The next step won't go as easy. I now need to work with things "other than numbers". I know there are many places where things could go wrong. I want unification, and that's not trivial. I might use an existing library for this, though... don't know yet.