KKNil allows you to create objects that behave in a silimar way to nil. A KKNil object will respond to the same methods its class instances or protocol conformers respond to, and return the equivalent of zero.
You can choose one of the two available factory methods to create a KKNil object. As the names suggest +[KKNil nilForClass:] will create an object that can be used in place of instances of that class and +[KKNil nilForProtocol:] will create analogous objects for a protocol.
Instances of this class can be useful when you want to return nil, but need to provide an object. This can happen for example when you need to put the result in an array or dictionary, or use the object as a forwarding target. In many cases it may be wiser to use nil or NSNull instead though.
KKNil uses a static 8192-byte array to provide zero return values to NSInvocations. If you intend to return structures larger than that by value, you may want to increase that size or change your approach. Also, because of NSInvocation limitations, KKNil doesn't support methods that use union types as arguments or return values.