The NYU Ada translator and interpreter

The NYU-Ada project is engaged in the design and implementation of a translator-interpreter for the Ada language. The objectives of this project are twofold: a) to provide an executable semantic model for the full Ada language, that can be used for teaching, and serve as a starting point for the design of an efficient Ada compiler; b) to serve as a testing ground for the software methodology that has emerged from our experience with the very-high level language SETL. In accordance with these objectives, the NYU-Ada system is written in a particularly high-level, abstract SETL style that emphasizes clarity of design and user interface over speed and efficiency. A number of unusual design features of the translator and interpreter follow from this emphasis. Some of these features are described below. We also discuss the question of semantic specification of programming languages, and the general methodology of "Software Prototyping" of which the NYU-Ada system is a sizeable example.