In Objective-C, I can easily say "if anyone calls a method on me that I don't implement, sent it to this object instead". I can also say "if anyone calls a meth

In Objective-C, I can easily say "if anyone calls a method on me that I don't implement, sent it to this object instead". I can also say "if anyone calls a method on me that I don't implement, do (foo) instead". C++, for example, has no equivalent language facility for these scenarios; in fact they're nonsensical since they would both fail to compile. You could build a similar system for C++ by making every object inherit from some base class that has a method performMethod( method, params) and replace all C++ method calls with your modified calls; but you're building a facility from scratch that comes out-of-the-box on Objective-C.