TR-94: An Exemplar Based Smalltalk

Abstract

Smalltalk is a rich object-oriented programming environment based on classes and a simple
inheritance scheme (though multiple-inheritance is provided non-primitively). The existing organization,
however, is overly restrictive. By changing the underlying base to exemplars and still supporting the notion of classes, we show how a much more powerful system can be obtained. In particular, we
describe the design and implementation of an exemplar based Smalltalk that not only suppo;. 1s multiple-inheritance (and-inheritance) at the kernel level but also multiple representations (or-inheritance). Additionally, we describe how an existing class-based Smalltalk can be transformed into .•n exemplar-based Smalltalk.