Adding dynamic interfaces to smalltalk

Abstract

The concept of interfaces is central to object-oriented methodologies and is one of the most attractive features of Java and COM. Although Smalltalk always had interfaces implicitly, in Smalltalk interfaces are not first-class objects: they cannot be conversed with, referred to, or reflected upon. Consequently, Smalltalkers have been deprived of such an important and useful tool. Since a fundamental feature of Smalltalk is that just about everything in the language is an implementation feature, explicit, static interfaces can be added to Smalltalk using Smalltalk itself with ease. However, such an addition would short-change the powerful dynamic aspects of Smalltalk. In this article we present Smalllnterfaces; a new ontology of dynamic interfaces which makes a powerful use of the dynamic nature of Smalltalk. Smalllnterfaces adds interfaces as honorary members to Smalltalk's extensive reflection mechanism, in a manner portable across the many Smalltalk variants.