“Objects” and “classes” are the basis of object-oriented programming. A class defines a collection of related data and the procedures that operate on the data. In a sense, a class can be thought of as a template. If multiple copies (or “instances”) of a class are required to store distinct sets of data, multiple objects of that class are created.
Objects and classes are used within GPL to provide additional functionality that is not part of the standard Basic Language and to organize functions that are related into easy-to-access groups. This functionality includes: mathematical operations, I/O operations, motion specifications, and robot control.
This section describes the general concepts associated with objects and classes. For illustration purposes, some of the objects and classes that are built into GPL are mentioned briefly in this section. The detailed description of these built-in GPL objects and classes are provided in later sections.