hackertube.io

Domain Modeling Made Functional - Scott Wlaschin - KanDDDinsky 2019

KanDDDinsky · talk · Watch on YouTube

Functional programmingSoftware architecture & designProgramming language design

What it is

Scott Wlaschin shows how statically typed functional languages, using F# examples, can model a business domain so that invalid states cannot be represented. The type system acts almost like an instant unit test at compile time.

Why Hacker News recommends it

HN treats it as the canonical, approachable example of domain-driven design with types and 'make invalid states unrepresentable'.

  • 3 people recommended it
  • 4 different months
  • 1 strong recommendations
  • first 2020, last 2026

What HN commenters said

  1. “this talk opened my eyes to the power of f# philosophy and type system”

    Opened commenter's eyes to F# philosophy and type system.

    devmunchies, 2020-08 · Strong recommendation · in “Draft of OCaml Scientific Computing book”

  2. “For anyone looking for a smaller introduction to this book”

    Short introduction to the book of the same name.

    Huggernaut, 2021-02 · Recommendation · in “Learn Functional Programming Visually”

  3. “offers a very appealing example for making making invalid states unrepresentable”

    Appealing example of making invalid states unrepresentable.

    rapnie, 2025-09 · Recommendation · in “'Make invalid states unrepresentable' considered harmful”

Excerpts from Hacker News comments, linked to the originals. Summaries and labels were written by a language model from those comments.

Topics: f#, functional programming, domain-driven design, type systems, scott wlaschin

Also recommended by the same people