Defining an S4 class

We will define the base Ant class called Ant. The class is represented in the following figure. The class is used to represent the fundamental aspects that we need to track for an ant, and we focus on creating the class and data. The methods are constructed in a separate step and are examined in the next section.

A class is created using the setClass command. When creating the class, we specify the data in a character vector using the slots argument. The slots argument is a vector of character objects and represents the names of the data elements. These elements are often referred to as the slots within the class.

Some of the arguments that we will discuss here are optional, but it is a good practice to use them. In particular, we will specify a set of default values (the prototype) and a function to check whether the data is consistent (a validity function). Also, it is a good practice to keep all of the steps necessary to create a class within the same file. To that...