Programs that Model Themselves

Work on reeection has frequently concentrated on programming languages and operating systems. This work either involves the use of tower reeection or meta-object protocols. The subject of this paper is a diierent form of reeection that is, we believe, more powerful and fundamental than the other kinds. Self modelling is a process that has not received attention in the literature; indeed, we believe that we are the rst to study the topic in a systematic fashion. We will explain the concept of a self-modelling program and describe some example programs that construct and manipulate models of themselves. The programs that we consider are: a learning program, a conceptual modelling system and a production rule interpreter. We also consider the beneets that are to be gained from engaging in self modelling and we show how the programs that we have described beneet from the additional work required of them. We indicate how additional power can be derived by engaging in self modelling.