Programming Objects with ML-ART An extension to ML with Abstract and Record Types

Abstract. Class-based objects can be programmed directly and e-ciently in a simple extension to ML. The representation of objects, based on abstract and record types, allows all usual operations such as mul-tiple inheritance, object returning capability, and message transmission to themselves as well as to their super classes. There is, however, no implicit coercion from objects to corresponding ones of super-classes. A simpler representation of objects without recursion on values is also described. The underlying language extends ML with recursive types, existential and universal types, and mutable extensible records. The lan-guage ML-ART is given with a call-by-value semantics for which type soundness is proved