GKS Based Graphics Programming in PROLOG

Abstract

It is evident that every computer language needs a graphics extension for the same reason as it needs input and output functions. Graphics may be seen as a powerful extension of the input and output facilities. This is even more evident for interactive languages like PROLOG. PROLOG is a computer language widely accepted for the purpose of symbolic computation. It is gaining popularity because of its simplicity and the new descriptive way of programming. A PROLOG program is a description of a problem in the form of some assertions and rules about how the solution may be inferred from the facts. It also provides some powerful data processing mechanisms, mainly relational data base facilities, tree searching with backtracking, and pattern matching. All these advantages make PROLOG suitable for many applications such as relational data bases, architectural design, natural language understanding and other AI fields. Most of the applications mentioned above also need computer graphics. Thus, integration of graphics into PROLOG can be seen as a step towards providing a more intelligent environment for these applications. The design of the graphics extension described in this paper is based on the principles and concepts of the Graphical Kernel System (GKS) [8], GKS provides all capabilities required by most of the PROLOG applications that produce computer generated pictures. It provides a suitable methodological framework for the creation of computer graphics programs because of its consistency, completeness, and compactness.