Using CASL to specify the requirements: a problem specific approach Christine Choppy (1) and Gianna Reggio (2) christine.choppy@lipn.univ-paris13.fr, reggio@disi.unige.it (1) LIPN, Université Paris XIII, France (2) Dipartimento di Informatica e Scienze dell'Informazione Universitá di Genova, Italy

WADT'99

For Cofi, session on methodology.

In [1] M. Jackson introduces the concept of problem frames to describe specific classes of problems, to help in the specification and design of systems, and also to provide a framework for reusability. He thus identifies some particular frames, such as translation frame (e.g. a compiler), control frame (or reactive system frames), and information system frame. Each frame is described along three viewpoints that are application domains, requirements, and design.

Our aim is to use CASL (or possibly a sublanguage or an extension of CASL if and when appropriate) to formally specify the requirements of classes of problems. This goal is related to methodology issues for CASL, that are here addressed in a more specific way, having in mind some particular problem frame, i.e. a class of systems.

It is hoped that this will provide both a help in using, in a really effective way, CASL for system specifications, a link with approaches that are currently used in the industry, and a framework for the reusability of CASL specifications. This approach will be illustrated with some case studies, e.g. the information system frame will be illustrated with the invoice system case study.

References

[1] M. Jackson, Software Requirements & Specifications: a lexicon of practice, principles and prejudices, Addison-Wesley, 1995.