Translating Corecursive Featherweight Java in Coinductive Logic Programming

Corecursive FeatherWeight Java (coFJ) is a recently proposed extension of the calculus FeatherWeight Java (FJ), supporting cyclic objects and regular recursion, and explicitly designed to promote a novel programming paradigm inspired by coinductive Logic Programming (coLP), based on coinductive, rather than inductive, interpretation of recursive function definitions. We present a slightly modified version of coFJ where the application of a coinductive hypothesis can trigger the evaluation of a specific expression at declaration, rather than at use site. Following an approach inspired by abstract compilation, we then show how coFJ can be directly translated into coLP, when coinductive SLD is extended with a similar feature for explicitly solving a goal when a coinductive hypothesis is applied. Such a translation is quite compact and, besides showing the direct relation between coFJ and coinductive Prolog, provides a first prototypical but simple and effective implementation of coFJ.