The problem with map/reduce/etc in ObjC is twofold: - Objective-C doesn't support generic value types for function arguments - Objective-C can't optimize away

The problem with map/reduce/etc in ObjC is twofold: - Objective-C doesn't support generic value types for function arguments - Objective-C can't optimize away method calls and therefore value boxing What that means in practice is that you can't write a generic version of map/reduce/etc without it being very slow even for things that should be very fast. If you want one that works efficiently for value types like integers, you must write a specialized version for each type. (I have written and sometimes use for convenience ObjC map/reduce/etc implementations.)