Declarative error diagnosis

This paper presents an error diagnoser which finds errors in logic programs which use the extended syntax and advanced control facilities. The diagnoser isdeclarative, in the sense that the programmer need only know the intended interpretation of an incorrect program to use the diagnoser. In particular, the programmer needs no understanding whatever of the underlying computational behaviour of the PROLOG system which runs the program. It is argued that declarative error diagnosers will be indispensable components of advanced logic programming systems, which are currently under development.