The aim of this study is to uncover and to resolve the fundamental issues facing the designer of an expression verifier system for an interactive program generator. The work presented here is intended to serve as the basis for an implementation of a verifier. It investigates such major questions as the division of the system into modules and the nature of the data structures used throughout the system. It also takes up, on occasion, the choice of algorithms to be used to accomplish certain system functions and the way in which these may be tailored to meet the special demands of this application. But it does not seek to provide a detailed description of the workings of each module in the system. In short, this study represents my conception of the design work needed to set the stage for an implementation.Computing and Information Scienc
