Object Logic Integration: A Multiparadigm Design Methodology and a Programming Language

In the past decade, there has been much research effort dedicated to combine the object-oriented programming paradigm and the logic programming paradigm. Most of this effort sheds light upon the philosophy of multiparadigm programming as a near ideal mental model for a wide class of problem domains. In this paper we propose a scheme for object and logic integration-the OLI scheme. This scheme contributes to the multiparadigm programming philosophy by putting forward a multiparadigm design methodology and describing a multiparadigm programming language. Above all, the OLI scheme integrates the object-oriented and the logic programming paradigms at the design and language levels with a precise and well-balanced interface so that each paradigm shares an equal and cooperating partnership in problem analysis and problem solving. An important property of the OLI language is that programmers can program either in one of the paradigms alone or in a mixed paradigm without sacrificing expressiveness and efficiency. We give a formal definition of the OLI language and study its semantics both from the logical perspective and the object-oriented perspective. By viewing objects as an enrichment of the Herbrand universe, we define the declarative and operational semantics of OLI. We show that OLI's operational semantics, a generalized form of SLD-resolution, is sound and complete. From the object-oriented point of view, the logic part of OLI is simply an object with logic programs as states and methods for performing logical deduction.