FUNLOG = functions + logic: a computational model integrating logic programming and functional programming (Rev. May 1983)

technical reportFunlog, a computational model which attempts to integrate functional programming and logic programming is described. The model supports computations with infinite data structures without the introduction of complex control issues at the user-level. Control characteristics are improved as compared with pure logic programming languages. A novel lazy reduction mechanism, pattern?driven reduction, for the underlying functional model is developed which cleanly and naturally achieves reduction?by-need. An abstract semantic unification algorithm is given upon which the resolution is based. Several example programs in Funlog are presented, including a program for finding the first N "lucky numbers". Programming in Funlog offers the flexibility of choosing between a backtracking free (determinate or indeterminate) computational framework and a non-deterministic one. Some implementation issues are also discussed