Domain Driven Design

This page contains links to the slides, video and code from my talk “Domain Modeling Made Functional”.

Here’s the blurb for the talk:

Statically typed functional programming languages like F# encourage a very different way of thinking about types. The type system is your friend, not an annoyance, and can be used in many ways that might not be familiar to OO programmers.

Types can be used to represent the domain in a fine-grained, self documenting way. And in many cases, types can even be used to encode business rules so that you literally cannot create incorrect code. You can then use the static type checking almost as an instant unit test – making sure that your code is correct at compile time.

In this talk, we’ll look at some of the ways you can use types as part of a domain driven design process, with some simple real world examples in F#. No jargon, no maths, and no prior F# experience necessary.

I am also planning to upload some posts on these topics soon. Meanwhile, please see the Designing with Types series, which covers similar ground.

You should also read “why type-first development matters” by Tomas Petricek and a great series of articles by Lev Gorodinski.

(Click image to view video)

The slides are also available from the links below:

• NDC London 2013 version (Slideshare), (Github)
• F#unctional Londoners 2014 version (Speakerdeck) with added sections on why OO, not FP is scary, and designing with states and transitions.

I have a book all about this topic – you can find more details on the books page.

If you want to follow along with the code, then:

• If you have F# installed locally, download this file.
• If you don’t have F# installed locally, you can run the code in your web browser at: tryfsharp.org/create/scottw/ddd.fsx