Some Approaches for Integration of Speciication Techniques

It is often useful to apply several speciication techniques within the same software development project. This raises the question how speciication techniques can be integrated. In this presentation we give three diierent examples of how this can be done. In the rst example, we summarise how the wide-spectrum approach has been used in the RAISE Speciication Language (RSL) to integrate algebraic and model-oriented, applicative and imperative, and sequential and concurrent speciication styles in a common syntactic and semantic unifying framework. The wide-spectrum approach has the advantage that one can stay within the same language throughout the development, but the price is a complicated semantics. Therefore, a related, but diierent approach, is to have a smaller, simple base language together with a number of extension languages in which additional speciication techniques have been integrated. In the second example, this approach is illustrated by the CoFI family of languages. If one is going to use two (or several) existing speciication languages with very diierent techniques, it is not appropriate to make an integration in one of the above styles. Instead one can make a syntactic and semantic link between the languages. In the third example we illustrate how the Duration Calculus (a real-time logic for expressing constraints on the duration of states) has been linked together with a real-time extension TRSL of RSL. The description of the two rst examples is summary with references to existing publications while the third one is a bit more detailed, since it concerns ongoing, unpublished research work. 1 RSL { a unifying, wide-spectrum approach The RAISE Speciication Language (RSL) Rlg92] is a wide-spectrum language in which algebraic and model-oriented, applicative and imperative, 1 and sequential and concurrent speciication styles have been integrated in a common syntactic and semantic framework. Hence, RSL is not a heterogeneous language consisting of one language for each speciication style, but a homogeneous language for which a uniform semantic formalisation has been made. As an example the applicative and imperative, and concurrent features have been integrated by having one common syntactic category of expressions for what in other languages are distinguished as value expressions , statements and process expressions, and they all denote values of the same semantic domain (processes). Hence, the expression 1 denotes the process which terminates immediately without waiting for any communications and without changing the state. For more details about the semantics, see Mil90, BD93] 1. Applicative Imperative …