Unification-free execution of well-moded and well-typed prolog programs

Abstract

In this paper, a static analysis of Prolog programs has been proposed to improve the efficiency by replacing run-time unification with matching. Programs for which run-time unification can be replaced by matching are called unification-free programs. We propose a set of sufficient conditions for unification-freedom improving the existing results and discuss the application of our results in improving WAM code of Prolog programs. Permutation and PRESS (a system developed at Edinburgh for solving symbolic equations) and programs flatten-dl, quick-sort-dl using difference-lists are example programs which can be handled by our results but not by the earlier results.