Theory and practice of middle-out programming to support program understanding

The paper describes recent work and results at Durham on what is termed as middle-out programming. The objective is to avoid the problems of top-down and bottom-up approaches by designing a high-level language specific to the application domain. An example of using this approach in the design of a large software system is presented. The main gain achieved in comprehension is through the large reduction in system size, and through a domain specific language. Other novel features of the approach are: the ability to provide a theoretical basis for user-enhanceable systems; the simplification of the capture of domain knowledge; and the concurrent engineering of the development and requirement stages.