Semantic Errors - Diagnosis and Repair

Abstract

In compiler technology, semantic error handling has too often used ad hoc techniques and terse messages of fixed content. In contrast, we present general models of diagnosis and repair of semantic errors and illustrate their use in the York Ada Workbench Compiler. The diagnostic model focuses upon the problem of selecting suitable information from which the programmer can locate and correct an error; following a brief discussion of an approach in which filters are applied to reports, and we give a more extensive account of a new approach using an interactive diagnostic interpreter. The repair model is based upon the idea of plastic nodes which are introduced into the compiler's internal representation of a program to replace normal nodes which are missing or erroneous.