How to “fake” ivars in an Obj-C category (iPhone)

Question

Update:

iPhone OS 3.1 has associated objects. However, the iPhone simulator does not. If you want to test associated objects code in the simulator, you should file a bug

Answer 1

I'll add an answer.

I found the original blog post, it was from Steve Degutis.

It basically involves replacing NSObject's methods for valueForUndefinedKey:, setValue:ForUndefinedKey:, and dealloc. Then using a static Dictionary to store any undefined keys.

Just about as nasty and fun as Louis's solution.