Objects and classes
An object is a collection of properties. Each of these properties has a name. These properties may be simple data values, such as numbers or strings, or references to code, such as function pointers and codeblocks. A property that references code is called a method. A method that is called by dBASE Plus in response to a user action is called an event.
Objects are used to represent abstract programming constructs, like arrays and files, and visual components, like buttons and forms. All objects are initially based on a class, which acts as a template for the object. For example, the PushButton class contains properties that describe the position of the button, the text that appears on the button, and what the button should do when it is clicked. All these properties have default values. Individual button objects are instances of the PushButton class that have different values for the properties of the button.
dBASE Plus contains many built-in, or stock, classes, which are documented throughout the dBL Language Reference. You can extend these stock classes or build your own from scratch with a new CLASS definition.
While the class acts as a formal definition of an object, you can always add properties as needed. This is called dynamic subclassing.