Using object-orientation to implement logic programming

Since their introduction, microcomputers have undergone a revolution in which the standard text-based input and output facilities have been replaced by powerful graphics and pointing devices. As a result, most applications are now driven by easy-to-use pictorial interfaces. Consequently, microcomputers are now mainly used by people who are not computer professionals and expect increasingly sophisticated and powerful applications. The resulting pressure on the software development industry has caused the adoption of powerful design and development techniques such as object-orientation, logic programming and pictorial languages. It now appears that a second revolution is imminent, involving the use of special hardware for such tasks as parallel processing and object management. The software component of this revolution involves the integration of various high level programming paradigms and their implementation on special hardware. We present an implementation of the logic programming language Prolog which uses object-orientation, and could therefore provide a basis for logic programming on object-oriented hardware. The implementation language, Prograph, is itself a product of the first microcomputer revolution, exploiting the graphics capabilities of modern microcomputers by expressing programs pictorially and providing powerful, picture-based program development tools.