The original intention was that more stuff gets cached (like parser trees). But none of the attempts ever resulted in a speed-up.

However, that's why the cache-dir stuff is in generic.py, and not in spritechache.py.

My feeling is that the code can always be made 'generic' if and when there's another real use-case for it, and that doing so pre-emptively makes it harder to follow.

If you feel strongly the other way I can change it back, but would rather not.