Compositional model for software reuse

Abstract

Emerald is a strongly-typed object-oriented language designed for programming distributed applications. Among other things, it provides abstract typing, type conformity, and complete separation of typing from implementation. While Emerald supports type inheritance, it does not support behaviour sharing among objects for simplifying distribution. To increase Emerald's utility in general-purpose programming, some support for software re-use is needed. Our research reveals that inheritance-based techniques commonly used in other object-oriented systems for obtaining re-use are inappropriate for Emerald. As an alternative to traditional inheritance, a compositional model, in which objects are composed from simpler entities, is proposed, outlined and analysed in this paper.