Language support for the specification and development of composite systems

The virtues of this approach to specification are expounded, and specification language features that are supportive of it are presented and it is shown how these are incorporated in the specification language Gist, which the group has developed.

Abstract

When a complex system is to be realized as a combination of interacting components, development of those components should commence from a specification of the behavior required of the composite system. A separate specification should be used to describe the decomposition of that system into components. The first phase of implementation from a specification in this style is the derivation of the individual component behaviors implied by these specifications. The virtues of this approach to specification are expounded, and specification language features that are supportive of it are presented. It is shown how these are incorporated in the specification language Gist, which our group has developed. These issues are illustrated in a development of a controller for elevators serving passengers in a multistory building.