Comment by sdegutis

This is also why dynamic languages like PyObjC, RubyObjC, RubyCocoa, MacRuby, Nu, and F# had difficulty bridging certain functions and methods, because you have to either create an insanely complex function that's able to take any @encoding and turn it into a runtime type, or you have to shimmy it with guesses for the most common ones like NSRect et al.