Automatic Program Debugging

Abstract

This paper presents a system <PHENARETE) uhich understands and improves lncomplet~ly defLned LISP programs, such as those.urLtten by students begtnntng to program in LISP. Thts system takes, as Lnput, the program uLthout any additional information. In order to understand the pro.gram, the system meta-evaluates l t, us log a library of pragmaticdescribing the construction and correction of general program constructs and a set of 6RBCLall~ts, describi~g the syntax and semantics of the standard LISP functions. The system can use Lts under~tandtng ~f the program . to detect errors in it, to debug them and, eventually, to JUStLfy Lts proposed modLfLcatLons. This paper gives a brief survey of the uorklng of the system, emphasizing some commented examples.