Domain Modeling Made Functional

Documenting the Domain

OK, we want to avoid biasing ourselves with technical implementations, but then how should we record these requirements?

We could use visual diagrams (such as UML), but these are often hard to work with and not detailed enough to capture some of the subtleties of the domain.

Later in this book we’ll see how to create an accurate domain model in code, but for now, let’s just create a simple text-based language that we can use to capture the domain model:

• For workflows, we’ll document the inputs and outputs and then just use some simple pseudocode for the business logic.

• For data structures, we’ll use AND to mean that both parts are required, such as in Name AND Address. And we’ll use OR to mean that either part is required, ...