Object Interdependencies, Behaviors, Semantics, and Types

摘要

Object types are abstract specifications of object behaviors and semantics. Object behaviors and semantics are abstractly indicated by object component inter-dependencies. In conventional object type systems, object component interdependencies are not taken into account, and as such, fundamental typing/subtyping loopholes that make program run-time errors inevitable still persist in current object type systems. In this short paper, we use Abadi-Cardelli's ζ-calculus to present a typing/subtyping problem that is due to the overlooking of object component interdependencies and causes program semantics trouble and run-time errors. We argue that, in order to rectify this kind of problem, object component interdependency information need to be included in object types and participate in object typing/subtyping.