Transformation of Logic Programs to FP Programs Based on Dataflows

AbstractThis paper is concerned with functionality of a logic program. Functionality based on input-output relations declared in predicates is not treated, but functionality of extensionalities of predicates, involved in a logic program, is realized by a dataflow computation and a functional programming (FP) system. By capturing the extensionality of a predicate as an atom sequence, we pay attention to the role of a definite clause together with already existing predicates in the resolution deduction, and abstractly interpret a definite clause as a function to provide a sequence emanating from its head (that is, conclusion) for already existing sequences unified with its body (premise expressed as a conjunction of predicates). Then we regard a logic program as a functional of functions of atom sequences. The functional is really a dataflow extracted from a logic program such that the dataflow preserves the same meaning. The atom sequence is replaced by a substitution sequence to affect a designated predicate, and the dataflow is thereby expressed by semantic functions over a sequence domain of substitutions, where the semantic functions are defined by algebraic manipulations of substitutions. The dataflow is represented by a functional form (FP program) of functions in accordance with substitution sequence variables. The FP program is a meaning preserving program transformed from a given logic program