Lazy Mixin Modules and Disciplined Effects

Programming languages are expected to support programmer's effort to structure program code. The ML module system, object systems and mixins are good examples of language constructs promoting modular programming. Among the three, mixins can be thought of as a generalization of the two others in the sense that mixins can incorporate features of ML modules and objects with a set of primitive operators with clean semantics. Much work has been devoted to build mixin-based module systems for practical programming languages. In respect of the operational semantics, previous work notably investigated mixin calculi in call-by-name and call-by-value evaluation settings. In this paper the authors examine a mixin calculus in a call-by-need, or lazy, evaluation setting.