Efficient reordering of Prolog programs

Abstract

The authors show how reordering of Prolog clauses, and especially goals, can prevent unnecessary search. They characterize the restrictions on reordering and show how they may be detected. They design a system of calling modes for Prolog, geared to reordering and discuss ways to infer them automatically. They present an improved method for determining a good goal order for Prolog clauses, and use it as the basis for a reordering system, showing how it can be guided by information about modes and restrictions to generate reordered Prolog that behaves correctly.<>