ON THE SEMANTIC DIVERSITY OF DELEGATION-BASED PROGRAMMING-LANGUAGES

The prototype-based programming model has always been difficult to cha racterize precisely. Its basic principle advocates concrete objects as the only mean to model concepts, yet current languages promote method ologies reintroducing abstract constructions to manage efficiently gro ups of similar objects. In this paper, we propose a rational reconstru ction of delegation-based programming languages that identifies progra mming models going beyond traditional prototypes. We also introduce a new classification of delegation-based languages, which clarifies thes e models, and we discuss their relative merits. We finally bring to th e fore the existence of more and more structured delegation-based lang uages forming a continuum between pure prototype-based languages and c lass-based ones.