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STEPWISE REFINEMENT REVISITED

IP.com Disclosure Number: IPCOM000128452D
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Sep-16
Document File: 13 page(s) / 48K

Publishing Venue

Software Patent Institute

Related People

Rajlich, Vaclav: AUTHOR [+3]

Abstract

In this paper, rigorous application of stepwise refinement is explored. The steps of definition, decomposition, and completion are described, where steps of completion is a newly introduced step. This combination of steps extends the use of stepwise refinement to medium-to- large systems. Notions of range, active objects, and composite interface are introduced. Verification of incomplete programs via interactive testing is described. The paradigm is demonstrated in an example. The relationship between the paradigm and the current programming languages is considered. It is argued that WHILE-DO loop is a harmful construct from this point of view.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

STEPWISE REFINEMENT REVISITED

Vaclav Rajlich

CRL-TR-13-83

THE UNIVERSITY OF MICHIGAN COMPUTING RESEARCH LABORATORY1

MARCH 1983

Room 1079, East Engineering Building
Ann Arbor, Michigan 48109
USA
Tel: (313) 763-8000

Stepwise Refinement Revisited by Vaclav Rajlich
Department of Computer and Communication Sciences University of Michigan
Ann Arbor, Michigan 48109

Abstract

In this paper, rigorous application of stepwise refinement is explored. The steps of definition, decomposition, and completion are described, where steps of completion is a newly introduced step. This combination of steps extends the use of stepwise refinement to medium-to- large systems. Notions of range, active objects, and composite interface are introduced. Verification of incomplete programs via interactive testing is described. The paradigm is demonstrated in an example. The relationship between the paradigm and the current programming languages is considered. It is argued that WHILE-DO loop is a harmful construct from this point of view.

[ Chapter ] 1. Introduction

Stepwise refinement is one of the oldest and most widely used methods of program design2.

Recently, a new interest in stepwise refinement has appeared in connection with software environments, where stepwise refinement is the methodology supported by specialized tools of the environments3.

1 Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors.

2 [ 3 ] Coffman, E.B., Problem solving and structured programming in Pascal, Addison Wesley, 1981. [ 4 ] Dijkstra, E.W., Notes on structured programming, in "Structured Programming", Academic Press, 1972. [ 10 ] Wirth, N., "Program development by stepwise refinement", Communications of ACM, April 1971, pp. 221-227. [ 11 ] Wirth,
N., Algorithms + Data Structures = Programs, Prentice-Hall, 1976.

3 [ 1 ] Barstow, D.K., Knowledge-Based Program Construction, North-Holland New York, 1979. [ 2 ] Cheatham, T.E. Jr., Holloway, G.H., Townsley, J.A., "Program refinement by transformation", Proc. 5th Conference on Software Engineering, San Diego, pp. 430-437. [ 5 ] Habermann, A.N., "An overview of the Gandalf project", Computer Science Research Report 1978-1979, Carnegie-Mellon University, Pittsburgh, 1979. [ 6 ] Hansen, Hans- Ludwig, Mullerburg, Monica, "Conspectus of software engineering environments", in A.J. Wassmerman, ed., Tutorial: Software Development Environments, IEEE Catalog No. EMO 187-5, pp. 462- 476. [ 7 ] Lyon, G., "Language-Based Editors/Interpreters", Proc. COMPSAC 82 Conf,, pp. 611-612, 1982. [ 8 ] Petrone, L., DiLeva,
A., Sirovich, F., "DUAL: An Interactive Tool for Developing Documented Programs by Step-Wise Refinements", Proc. 6th International Conference on Software Engineering, IEEE Catalog No. 82CH1795-4, pp. 350-357. [ 9 ]

University of Michigan Computing Research Laboratory Page 1 Mar 01, 1983

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