Constraint functional logic programming over finite domains

Abstract

In this paper, we present our proposal to Constraint Functional Logic Programming over Finite Domains (CF LP (FD) ) with a lazy functional logic programming language which seamlessly embodies finite domain (FD) constraints. This proposal increases the expressiveness and power of constraint logic programming over finite domains (CLP (FD) ) by combining functional and relational notation, curried expressions, higher-order functions, patterns, partial applications, non-determinism, lazy evaluation, logical variables, types, domain variables, constraint composition, and finite domain constraints.We describe the syntax of the language, its type discipline, and its declarative and operational semantics. We also describe T OY(FD), an implementation for CF LP (FD) , and a comparison of our approach with respect to CLP (FD) from a programming point of view, showing the new features we introduce. And, finally, we show a performance analysis which demonstrates that our implementation is competitive with respect to existing CLP (FD) systems and that clearly outperforms the closer approach to CF LP (FD) .

A Semantic Framework for the Declarative Debugging of Wrong and Missing Answers in Declarative Constraint Programming

“…As future work, we plan several improvements of DDT , such as enabling the diagnosis supporting finite domain constraints (Estévez et al, 2009;Fernández et al, 2007), and providing new facilities for simplifying the presentation of queries to the user. In this sense, some important pragmatic problems well known for declarative diagnosis tools in FP and CLP languages also arise in our context: both the CTs and the acas at their nodes may be very big in general, causing computation overhead and difficulties for the user in answering the questions posed by the debugging tool.…”

“…The aim of this chapter is to present a logical and semantic framework for diagnosing wrong and missing computed answers in CFLP(D) (López et al, 2006), a newly proposed generic programming scheme for lazy Constraint Functional-Logic Programming which can be instantiated by any constraint domain D given as parameter, and supports a powerful combination of functional and constraint logic programming over D. Sound and complete goal solving procedures for the CFLP(D) scheme have been obtained (López et al, 2004). Moreover, useful instances of this scheme have been implemented in the TOYsystem (López & Sánchez, 1999) and tested in practical applications (Fernández et al, 2007). Borrowing ideas from CFLP(D) declarative semantics we obtain a suitable notion of intended interpretation, as well as a kind of abridged proof trees with a sound logical meaning to play the role of CTs.…”

Multi-paradigm Declarative Languages

“…Thus, typical applications of constraint logic programming can be covered and combined with features of lazy higherorder programming [10,19,30,31,67,70,77]. As an example demonstrating the compactness obtained by combining constraint programming with higher-order features, consider a solver for SuDoku puzzles 6 with finite domain constraints.…”

Parameterized Models for On-Line and Off-Line Use

“…This has a considerable advantage compared to special-purpose Functional Constraint (Logic) Programming (FCP) languages such as Curry [7] or TOY [5]. We directly obtain state-of-the-art functional programming support with zero effort, allowing us to focus on constraint programming itself.…”