The class command is similar to other attribute commands, and it can be used to either set or get information about an object's class. An object's class is a vector, and each item in the vector is the name of a class. The first element in the class vector is the object's base class, and it inherits from the other classes as you read from left to right.

We first focus on the situation where an object has a single class and will examine inheritance in the section that follows. The example examined throughout this chapter is used to simulate one experiment that follows a geometric distribution. The idea is that you repeat some experiment and stop when the first success occurs. First, we examine two classes, and we construct a function that will take an action depending on the class name. The first class is used to represent a fair, six-sided die. The die will be rolled, giving an integer between 1 and 6 inclusive, and the experiment stops when a 1 is returned. The...