Le hachage parfait fait-il un parfait test de sous-typage?

Subtype tests are an important issue in the implementation of object-oriented programming languages. Many techniques have been proposed but none of them perfectly fullfills the five requirements that we have identified: constant-time, linear-space, multiple inheritance, dynamic loading and inlining. In this paper, we propose to apply a well known technique, perfect hashing, and we show that it responds rather well in meeting these requirements. Furthermore, in the framework of JAVA like languages—characterized by single inheritance of classes and multiple subtyping of interfaces—perfect hashing applies also, at the same time, to method invocation when the receiver is typed by an interface. MOTS-CLÉS : coloration, coercition de types, hachage parfait, héritage simple, héritage multiple, interfaces, langage à objets, tables de méthodes, test de sous-typage