The theory of classification part 15: mixins and the superclass interface

The fundamental concepts of mixin, an object oriented language, are discussed. Intended to be combined with any other object, mixin is a freestanding record of extra fields. Mixins are also the primitive building blocks in languages with inheritence-like mechanisms. A mixin can be combined with many different base classes, to yield different extended classes which contain the combined base and mixing features. A mixin has a superclass interface, describing the kind of class from which it expects to inherit.