Using Mixin Technology to Improve Modularity

In object-oriented languages, aspects can be defined by generalizing the idea of a class to that of a mixin. Mixins, which can be implemented as generic types, become aspects when they contain code for multiple classes. In this chapter, we describe mixins and we explain how mixins can be used to define aspects. We demonstrate the flexibility of mixin programming by prototyping a graphical user interface library that can be configured to run on dissimilar devices. We describe additional language and compiler sup-1 2 Chapter 33 Using Mixin Technology to Improve Modularity port that increases the effectiveness of mixin programming. We conclude by proposing some new ideas about how mixins, and generic types in general, can be better supported in object-oriented languages. One approach to reducing the cost of software is to make software easier to reuse and, in doing so, to reduce the risk and expense of developing new ap