A Model of Programming Environment

the motivation behind the work in interactive programming environments is to increase both our productivity and the quality of the software we produce. Unfortunately, it is not easy for a designer to create a programming environment for a new language; experience could be gained analysing systems already developed for other languages, but the process involved is slow and often existing systems can't be adapted to the new language. In this paper we present a model, the attribute computation tree, which can describe in abstract the interactions of a functional language interpreter with the components of a programming environment. The main property of the model is its ability to represent the concept of interruption of a computational process; this property allows the study of most interactions between the interpreter and the modules of the environment. Furthermore the model is independent from the programming language and the techniques used during the implementation. As an example of possible application of the attribute computation tree we have implemented a tool based on program transformation techniques for the local trace of Lisp programs.