Objective C Basics 3.2.1. The variable type that is added by Objective C is id . All objects can refer to themselves by using the label self . This is necessary if, in the code that defines the object, the programmer wants to make the object execute one of its methods. For example, suppose an object has a method called updateRecords .
All objects can refer to superclass by the name super .
If you look in a directory where some Objective C Swarm code resides, you will see files in pairs, such as ObserverSwarm.h and ObserverSwarm.m , ModelSwarm.h and ModelSwarm.m , and so forth. The variables defined in this list can be used by any of the methods defined for the class. When that method is called, the receiving code must be able to accept a return of that type. In contrast, the method step does not specify a return type. That means the default type, id , is returned.