Integration of Logic and Functional Languages Based on Dataflow

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The technical merits of logic and functional languages have been widely acknowledged, and the integration problems of these languages have arisen to be discussed from formal semantics points as well as practical implementation techniques(See, for example, De Groot and Lindstrom, 1986). Several languages have been developed in focus on integration of equality with a logic language. The primary computing mechanism for such languages is resolution-based, but term rewriting rules, narrowing and so on should be unified with resolutions. How to unify them has caused interesting aspects even in logic programming. This research project has been following the direction of such integration, but avoids the way of unifying different computings. Taking the expressiveness of FP programs and algebraic manipulationinvolved in resolution deductions of logic programs into account, we have a logic language with FP functions equalityFPLOG, for which semantics is formulated by means of data ; flow, differe … More nt from the way of defining semantics for LEAF(Giovannetti et al., 1991). The proposed semantics in this report reflects and suggests dataflow computing for both logic languages and equations consisting of FP programs.For the goal to semantics for FPLOG, we firstly deal with semantics for logic program using dataflow construction. The semantic domain is a sequence domain based on the Herbrand base or the quotient set consisting of equivalence classes of idempotent substitutions. As related topics, we are concerned with nondeterministic dataflow and logic programs with communication channels. There is a formulation of the network of communicationg logic programs. The network might express the dataflow computing for a sequential logic program.Then the transformation technique from a logic program into a functional program, especially an FP program, is provided. The transforamtion process does not take the input-output mapping involved in predicates as Debray and Warren(1989), but the interpretation that each definite clause translates substitution sets or sequences to a substitution set or sequence, caused by inferences such that the substitution set or sequence is means of virtual representation of atom sets. The translation might be expressed by an FP program, which is also regarded as an extracted functional from a logic program.Finally we have FPLOG, which consists of definite clause sets involving equalities for terms containing FP functions. Becauses the equality might be realized and evaluated by dataflow computing, dataflow computing for FPLOG is suggested such that semantics might reflect it. Less