A Tool for Logic Program Refinement

The re nement calculus provides a method for transforming speci cations to executable code, maintaining the correctness of the code with respect to its speci cation. In the original re nement calculus, the target language is an imperative programming language, but more recently a re nement calculus for deriving logic programs has been proposed. Due to the amount of detail involved, the manual re nement of programs is a tedious and timeconsuming task, and is therefore an obvious candidate for tool support. Several tools exist for the imperative re nement calculus, and in this paper we describe a prototype tool to support the recently developed re nement calculus for logic programs. The tool was developed using Ergo, an interactive theorem prover. To provide tool support for the calculus, its underlying semantic model was de ned within Ergo, and the laws of the calculus were proven in that framework. We illustrate the tool using a simple example re nement.