An Algebraic Framework for Separate Type-Checking

We address the problem of deening an algebraic framework for modularization supporting separate type-checking. In order to do that we introduce the notions of abstract type system and logic of constraints and we present a canonical construction of a model part, on top of a logic of constraints. This canonical construction works under standard assumptions on the underlying type system. We show that the framework is suitable for deening the static and dynamic semantics of module languages, by giving a concrete example of construction on top of the type system of a simple typed module language. As a result, the subtyping relation between module interfaces is captured in a natural way by the notion of signature morphism.