Ada Ravenscar Code Archetypes for Component-based Development

We promote a model-driven software development that centres on component-orientation. In keeping with Dijkstra’s principle of separation of concerns, we want the user design space to be limited to the internals of components – for which strictly sequential functional code is to be used – and the interfaces provided to and required from other components, where extra-functional requirements are declaratively specified by means of annotations. We want the user model to be directly amenable to response time analysis. To this end we prescribe that the component model must statically bind to a computational model that matches the analysis theory in use. We want to ensure semantic preservation across the entire transformation chain, from the user model, to the analysis model, to the implementation model (i.e., the code) and, eventually to the execution environment. The Ada Ravenscar Profile is an excellent candidate implementation language for use in our endeavour. In this paper we present a set of code archetypes written against the constraints of the Ravenscar Profile, which we developed in conformance with our notion of separation of concerns, to drive the model to code transformation step of our development infrastructure.