Using transformations in specification-based prototyping

The authors explore the use of software transformations for software evolution. Meaning-preserving program transformations have been widely used for program development from a fixed initial specification. They consider a wider class of transformations to support development in which the specification evolves, rather than being fixed in advance. A new and general classification of transformations based on their effect on system interfaces, externally observable behavior, and abstraction level of a system description is presented. This classification is used to rearrange chronological derivation sequences containing meaning-changing transformations into lattices containing only meaning-preserving transformations. A process model for software evolution that utilizes prototyping techniques is described. Ways in which this class of transformations can be used to support such a process are considered. A set of examples are presented to illustrate the ideas. Software tool support and directions for future research are discussed