domain driven design

These are the notes I took during the sessions. Some of them don’t have a clear structure, but are individual, unconnected ideas.

2019 was the first year I have participated in the Advent of Code challenges, encouraged by my colleague Jan. I wanted to make it an opportunity to learn new programming languages and focus on functional programming. I started with Racket, tried out Elixir and re-wrote the challenges that involved the “intcode computer” in Scala. This post is a review of the programming languages and the event itself.

When you apply the principle of Domain Driven Design (DDD) to your code, you start to notice all the small “rules” of the domain. Rules like “A name must not consist of whitespace, must have its whitespace trimmed on both ends and cannot be empty." Or “A donation amount must be greater than zero." Or “A book must have at least one page." It’s important that you can’t create value objects that violate those rules.

Keynote by David Snowden An inspiring talk about complexity and modeling, using the Cynefin framework to understand the nature of your domain (Complex/Complicated/Simple/Chaotic) and how to model and measure success according to that nature. What stood out to me was the idea that complex domains - like ecosystems, financial markets, large organizations or even “society” itself - can’t be analyzed and fully understood like complicated domains. Thus, they can’t be “modeled”, since every abstraction will miss crucial behavior.