Unifying nominal and structural typing

Abstract

In this article, I argue for a typing scheme for modeling that unifies the hitherto separated approaches of nominal and structural typing. Both these approaches have their respective advantages and disadvantages, and I suggest a unifying approach that provides one with the best of both worlds on demand. The ultimate goal is to make a contribution toward removing the gulf currently running through the modeling community that is created by the differences between explanatory and constructive modeling with their dependence on structural and nominal typing, respectively. To this end, I first characterize the typing disciplines underlying these different schools of thought, then identify their respective trade-offs, subsequently observe what aspects of these rather different typing approaches are compatible with each other and which are inherently incompatible, and finally propose a scheme that supports fluid transitioning between the approaches.