A Program Development Tool

In this paper we describe how we have combined a number of tools (most of which are tailored to a particular programming language) into a single system to aid in the reading, writing, and running of programs. We discuss the efficacy and the structure of two such systems, one of which has been used to build several large application programs. We report some of the experience we have gained in evolving these systems. We first describe the system components which users have found most important; some of the facilities described here are new in the literature. Second, we attempt to show how these tools form a synergistic union, and we illustrate this point with a number of examples. Third, we illustrate the use of various system commands in the development of a simple program. Fourth, we discuss the implementation of the system components and indicate how some of them have been generalized.