Object-oriented and frame-based programming in CommonORBIT

Objects are representations of entities in a domain which is modeled in a computer. Each object encapsulates the knowledge relevant to one abstract concept or physical object in the real world. This knowledge may consist of data but also of procedures which are applicable to the object. Using the metaphor of a society of communicating entities, these procedures are activated by sending messages to objects. In an applicative view of object-oriented programming, however, procedures are called as generic functions rather than by sending messages. Object-oriented languages allow knowledge to be shared between several objects by a mechanism called inheritance. The object-oriented language which is discussed below is CommonORBIT, an extension to Common LISP. It is an easy but powerful language, which offers a representation based on structured objects but is also inspired by frame-based systems.