A Knowledge-Based Program Editor

This paper describes an initial implementation of an in terac t ive programming assistant system called the Programmer's Apprent ice (PA). The PA. is designed to be midway be tween an improved programming methodology and an automatic programming sys tem. The intent ion is that the programmer wil l do the hard par ts of design and implementation while the PA wil l assist him wherever possible. One of The major underpinnings of the PA is a representa t ion (cal led a plan) for programs which abstracts away f rom the inessent ial features of a program, and represents the basic logical p roper t i es of the algori thm explicit ly. The current system is composed of four par ts : an analyzer that can construct the plan for a program; a coder that can create program text corresponding to a plan, a l ibrary of plans for common algorithmic fragments; and a plan editor which makes it possible for a programmer to modify a program by modifying its plan. The greatest leverage provided by the system comes from the fact that a programmer can rapidly and accurately bui ld up a p rogram by re fe r r i ng to the fragments in the l ibrary and f rom the fact that the edi tor provides commands specifically designed to faci l i tate p rog ram modif ication.