Composing Software

Functional Mixins

Functional mixins are composable factory functions which connect together in a pipeline; each function adding some properties or behaviors like workers on an assembly line. Functional mixins don’t depend on or require a base factory or constructor: Simply pass any arbitrary object into a mixin, and an enhanced version of that object will be returned.

Functional mixin features:

• Data privacy/encapsulation
• Inheriting private state
• Inheriting from multiple sources
• No diamond problem (property collision ambiguity) – last in wins
• No base-class requirement

Motivation

All modern software development is really composition: We break a large, complex problem down into smaller, simpler problems, and then compose solutions to form an ...