A Prolog Programming Assistance System

Abstract

This chapter investigates a Prolog Programming Assistance System (PAS) from two points of view. The first displays, as a tree, the calling relationships among the predicates in the program being developed by the user. The second implements a library of commonly-used predicates, such as append and member, for automatic inclusion in user programs. The tree display is intended to facilitate the reading of Prolog programs (which, as linear sequences of Horn clauses, can otherwise be difficult to understand). Similar facilities are available in LISPs that provide ‘pretty printers’ (discussed more fully in Chapter 3), which allow for the structural display of LISP definitions. Indeed, we have tried in developing the present PAS to make it list programs in a layout that is as easy to understand as possible (the listings in this book are examples of those efforts).