Behavioral Re ection in a Prototype-Based Language

In MCD92], we have contributed a reeective model for a prototype-based language based on the lookup apply re-ective introspection protocol. Here, we pursue this work by including a reiication of continuations. Hence, we provide continuations as rst-class objects and convert our previous protocol to handle them. First-class continuations provide much more control over the current computation. Also, this new model establishes the clear link between reeection in object-oriented and reeective towers as exampliied by 3-Lisp Smi84]. Object-orientedness provides reeection a more principled and encapsulated programming style, making it easier to use. In this paper, we establish the correctness of this new model, namely that any message in the system will be executed in a nite number of computation steps. This fact is based on a limited number of hypothesis independent from the implementation but from which we derive fundamental clues to derive an evaluator for the language. 1 Introduction Reeection, understood as the construction of self-awared systems, is a persistent source of challenge. The mere feeling of touching the essence of computing, but also the tremendous potential for new applications insure a continuous quest for understanding its foundations. The goal of this paper is to propose and study in depth a minimal model of behav-ioral reeection for a prototype-based language. Object-oriented programming is dominated by the class and metaclass approach that provides it a highly satisfactory solution to the problem of structural reeection, which is concerned by the complete reiication of data structures and programs as rst class entities. The problem of behavioral reeection, concerned by the reiication of objects' execution, is not established on similar rm grounds yet.