A Survey of Program Transformation With Special Reference to Unfold/Fold Style Program Development

This paper consists of a survey of current, and past, work on program transformation for the purpose of optimization. We first discuss some of the general methodological frameworks for program modification, such as analogy, explanation based learning, partial evaluation, proof theoretic optimization, and the unfold/fold technique. These frameworks are not mutually exclusive, and the latter, unfold/fold, is certainly the most widely used technique, in various guises, for program transformation. Thus we shall often have occasion to: compare the relative merits of systems that employ the technique in some form, andj compare the unfold/fold systems with those that employ alternative techniques. We also include (and compare with unfold/fold) abrief survey of recent work concerning the use of formal methods for program transformation.