"If you're planning to add type-checking - so that objects claiming to be tables have to implement certain methods, or the object call immediately errors (gets _called_ on it ^-^) - that's an interesting direction."
I wasn't planning on it, no, and I think we can still gain uses out of types-as-interfaces even without type checking. However, Traits.js might just change my mind. But that would be more complicated than my simple object.arc library.
