Functional Counterparts of some Logic Programming Techniques

Drawing on experience of translating a Prolog program into Haskell, a range of correspondences between logic and functional programs are discussed. Despite the differences of underlying paradigms, in many cases we can find close counterparts between the two programming schemes. 1. Introduction To anyone surveying the entire range of programming languages and systems, logic programming and functional programming surely appear similar in many ways. Both have their origins in mathematical ideas rather than in the design of computing machines. Both are declarative, offering a programming style quite removed in principle from the low-level store-and-jump model of conventional imperative languages. Yet in each paradigm there are quite distinctive programming techniques. At least, that is the impression often given by textbooks (though few discuss both paradigms in depth). In this paper we look at some techniques often regarded as part of the distinctive repertoire of the logic programmer. W..