Added

Your solution should work now.

@constablebrew could you paste in your erroring solution?

Okay, eval and new Function now throw errors. This should get rid of the "lazy" cheating cases, but still leave room for other solutions and creative cheating.

eval and new Function have been disabled.

Yes I wasn't necessarily trying to force people to do bitwise calculations. I assumed the array concat solution would show up at some point. I just wanted to avoid the case where you were calling a seperate function. In fact your other solutions are rather clever and I'm not sure I'd want to discourage them either.

You are a sneaky individual. I'll think about some revisions.

Clever, but this certainly isn't in the spirit of the kata. I guess I'll need to add a test case checking function calls within the add function.