Towards Interactive Logic Programming

Adding interaction to logic programming is an essential task. Expressive logics such as linear logic provide a theoretical basis for such a mechanism. Unfortunately, none of the existing (linear) logic languages can model interactions with the user because they uses provability as the sole basis for computation. In the operational semantics based on provability, executing the additive-conjunctive goal G0&G1 from a program P simply terminates with a success if both G0 and G1 are solvable from P. This is an unsatisfactory situation, as a central action of & – the action of choosing either G0 or G1 by the user – is missing in this semantics. We propose to modify the operational semantics above to allow for more active participation from the user. We illustrate our idea via Prolog, an extension of Prolog with additive goals. keywords: interaction, logic programming, linear logic, computability logic.