Continuations for Parallel Logic Programming

This paper gives denotational models for three logic programming languages of progressive complexity, adopting the \logic programming without logic" approach. The rst language is the control ow kernel of sequential Prolog, featuring sequential composition and backtracking. A committedchoice concurrent logic language with parallel composition (parallel AND) and don't care nondeterminism is studied next. The third language is the core of Warren's basic Andorra model, combining parallel composition and don't care nondeterminism with two forms of don't know nondeterminism (interpreted as sequential and parallel OR) and favoring deterministic over nondeterministic computation. We show that continuations are a valuable tool in the analysis and design of semantic models for both sequential and parallel logic programming. Instead of using mathematical notation, we use the functional programming language Haskell as a metalanguage for our denotational semantics, and employ monads in order to facilitate the transition from one language under study to another. Keywords Parallel logic programming, basic Andorra model, denotational semantics, continuations, monads, Haskell. 1

CONTINUATIONS FOR REMOTE OBJECTS CONTROL

Abstract. We have recently introduced the ”continuation semantics for concurrency” (CSC) technique in an attempt to exploit the benefits of using continuations in concurrent systems development. CSC is a general technique for denotational semantics which provides excellent flexibility in the compositional modeling of concurrent control concepts. In this paper, we present a denotational semantics designed with CSC for a distributed languages incorporating two control concepts which have not been modeled denotationally before: remote object (process) destruction, and cloning. 1

Comparative Metric Semantics for Commit in Or-Parallel Logic Programming

For the control flow kernel of or-parallel Prolog with commit an operational and a denotational model are constructed and related using techniques from metric semantics. By maintaining explicit scope information a compositional handling of the commit for the denotational model is established. By application of an abstraction function, which deletes this extra information the operational semantics is recovered