Nothing. Lisp's a general purpose multi-paradigm programming language, while Prolog isn't. If you need a rules engine, great, but there's no reason to shoe-hor

Nothing. Lisp's a general purpose multi-paradigm programming language, while Prolog isn't. If you need a rules engine, great, but there's no reason to shoe-horn general programming problems into the Prolog model. If you have JESS / Java or CLIPS / C, or generally, a rules engine for your favourite language, what does Prolog bring to the table?