Towards tool support for design patterns using program transformations

Design patterns have greatly helped spreading a limited number of well-tried solutions to recurring object-oriented problems. But as new patterns are introduced at a steady rate, the concept must evolve so that tools can help programmers not to be lost, facing a host of patterns. In this paper, we propose that design patterns be systematically analyzed and reformulated to exhibit a reasoning binding solutions to precisely stated problems, given a set of mechanisms. We show on some creational patterns how these mechanisms can be described as program transformations and how an assistant tool could systematically explore the set of potential solutions induced by these transformations. This would both help the selection and the instantiation of the appropriate patterns. NOTE. — This paper is an improved and at least twice longer version of [ZIA 00]. RESUME. Les modeles de conception ont largement participe a la diffusion de solutions eprouvees a des problemes recurrents de conception et de programmation a objets. Pourtant le concept doit a present evoluer pour que les programmeurs puissent gerer le nombre croissant de ces modeles. Dans ce papier nous proposons que les modeles de conception soient systematiquement analyses et reformules pour exhiber un raisonnement liant les solutions a des problemes decrit precisement, etant donne un ensemble de mecanismes. Nous montrons sur certains modeles createurs comment ces mecanismes peuvent etre decrits comme des transformations de programmes et comment un outil d'assistance pourrait systematiquement explorer l'ensemble des solutions possibles induit par ces transformations. Ceci faciliterait la selection mais aussi l'instanciation des modeles appropries.