A survey of constraint-based programming paradigms

Constraints support a programming style featuring declarative description and effective solving of several classes of problems. Unlike basic primitives of other programming languages, constraints do not specify computing operations, but rather the properties of a solution to be found. In this paper, we give a survey of the main formalisms based on constraints: Constraint Satisfaction Problems, Constraint Logic Programming and Concurrent Constraint Programming. We outline recent extensions of these approaches and we discuss ongoing trends of research.