A Declarative Debugging Environment for DATALOG.

In this paper we discuss a declarative approach to debugging for DATALOG, a logic programming language based on a bottom-up evaluation strategy. We focus on the DATALOG implementation provided by the ALPE programming environment. In ALPE, a DATALOG program is translated by the Logic Query Compiler — LQC — into a Prolog program whose top-down evaluation corresponds to the bottom-up evaluation of the source DATALOG program. It follows then that the computational models of the source and the compiled programs are completely different. This makes the use of a tracer practically pointless.