Genericity versus inheritance

Genericity, as in Ada or ML, and inheritance, as in object-oriented languages, are two alternative techniques for ensuring better extendibility, reusability and compatibility of software components. This article is a comparative analysis of these two methods. It studies their similarities and differences and assesses to what extent each may be simulated in a language offering only the other. It shows what features are needed to successfully combine the two approaches in a statically typed language and presents the main features of the programming language Eiffel, whose design, resulting in part from this study, includes multiple inheritance and limited form of genericity under full static typing.