Adding Partial Functions to Constraint Logic Programming with Sets

CRISTIÁ, MAXIMILIANO; ROSSI, GIANFRANCO; FRYDMAN, CLAUDIA

THEORY AND PRACTICE OF LOGIC PROGRAMMING

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2015

1471-0684

Partial functions are common abstractions in formal specification notations such as Z,B and Alloy. Conversely, executable programming languages usually provide little or nosupport for them. In this paper we propose to add partial functions as a primitive featureto a Constraint Logic Programming (CLP) language, namely {log}. Although partialfunctions could be programmed on top of {log}, providing them as first-class citizens addsvaluable flexibility and generality to the form of set-theoretic formulas that the languagecan safely deal with. In particular, the paper shows how the {log} constraint solver isnaturally extended in order to accommodate for the new primitive constraints dealingwith partial functions. Efficiency of the new version is empirically assessed by runninga number of non-trivial set-theoretical goals involving partial functions, obtained fromspecifications written in Z.