Abstract

Constraints are declarative statements of relations among elements of the language's computational domain, e.g., integers, booleans, strings, and other objects. Orthogonally, the tools of object-oriented programming, including encapsulation, inheritance, and dynamic message binding, provide important mechanisms for extending a language's domain. Although the integration of constraints and objects seems obvious and natural, one basic obstacle stands in the way: objects provide a new, larger, computational domain, which the language's embedded constraint solver must accommodate. In this paper we list some goals and non-goals for an integration of constraints and object oriented language features, outline previous approaches to this integration, and describe the scheme we use in Kaleidoscope'91, our objectoriented constraint imperative programming language. Kaleidoscope'91 uses a class-based object model, multi-methods, and constraint constructors to integrate cleanly the encapsulation an...

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