This paper has been accepted by the ITT Workshop on Reusability in Programming, Newport RI, September 7-9, 1983.There has been a long-standing desire in computer science for a way of collecting and using libraries of standard software components. Unfortunately, there has been only limited success in actually doing this. We believe that the lack of success stems not from any resistance to the idea, nor from any lack of trying, but rather from the difficulty of choosing an appropriate formalism for representing components. In this paper we define five desiderata for a good formalization of reusable software components and discuss many of the formalisms which have been used for representing components in light of these desiderata. We then briefly describe a formalism we are developing — the Plan Calculus — which seeks to satisfy these desiderata by combining together the best features of prior formalisms.MIT Artificial Intelligence Laborator
