Design issues of fuzzy logic programming languages

Logic programming (LP) has been successfully applied to solve many problems in artificial intelligence and many other areas. However, LP is unable to deal with uncertain, imprecise or vague information. On the other hand, fuzzy sets and fuzzy logic have demonstrated their applicability in dealing with uncertainty, and have motivated the research on extending classic LP to add fuzzy reasoning. However, a full fledged implementation of a fuzzy logic programming language universally accepted and/or in production does not exist yet. There are many reasons for this, and we present some of them. The aim of the paper is to briefly survey some of the major design problems we faced in implementing a fuzzy version of a Prolog-like logic programming language.