language: en

A Relational-Functional Integration for Declarative Programming

Harold Boley
DFKI
Box 2080, 67608 Kaiserslautern, Germany
boley@informatik.uni-kl.de

Abstract. A relational-functional kernel language is introduced that integrates essential declarative constructs: logic variables and non-determinism from the relational paradigm with nested and higher-order operations from the functional paradigm. Operator definitions use `valued clauses', subsuming relational Horn clauses and functional (conditional or unconditional) directed equations. Their semantics complements the atoms in relational Herbrand models by `molecules', which pair functions, applied to argument terms, with returned-value terms. All abstract notions are illustrated by concrete declarative programs.

1 Introduction