Designing Elixir Systems With OTP

Chapter 4 Build a Functional Core

In this chapter, we’ll dive into the functional core, sometimes called the business logic of your component. Functional-core is the “F” for “fun” in “Do fun things with big loud worker-bees.” In the previous chapter, we worked with data. We carved our project into hollow modules holding structs that form our data skeleton. In this chapter, we’ll fill those empty modules up with functions, each logically addressing a part of the whole functional core. The following figure shows where this core fits:

A functional core is a group of functions and the type definitions representing the data layer, organized into ...