Toward tools to support the Gries/Dijkstra design process

Abstract

We are investigating mftwexe dean processes using a thxee part approach. Fox a design method of interest, we first perform walkthroughs on a number of small problems. Second, we construct a sim~,latioll program which duplicates the designs produoed by the wallrthn~ughs, and third, we constreet a process program that supports human application of the method. We have been putmin 8 ~ program fox the foxreal design process developed by Dijhtra and Giles. In this paper, we describe our first step towards process programming this method: ISLET, a lanbq~tge-cxlented program/proof editor. ISLET suppoas simple stepwlse refinement with proof by automatically generating and mechanically eetlifying verification conditions. In addition, through ISLET the programmer ihas access to a librmy of pre-vefified cliches that can be used to create programs more easily. We have constmcted a prototy1~ implementation in Prolog and used it to generate a number of example designs.