Types - Primitive, Named, Phantom, Opaque, Custom, State Machines, and Type Driven Design

[rupert]

Good collection of resources, and thanks for taking initiative to try and gather some of this stuff together. I don’t think you’ll find a book or any resource that covers it all - but certainly a great set of resources for someone who might want to write such a book.

You mentioned state machines? Here are some of the discussions that have been on here around that topic:

Can phantom types be used to restrict the possible transitions in a state machine?

Hi, there was some discussion about state machines in Elm on Slack and it was suggested that it might be possible to use phantom types to control possible state transitions in a state machine. I have no idea how. Suppose you have some set of states defined as a tagged union: type Game = Loading | Ready | InPlay GameState -- GameState models score, position, enemies still alive etc. | GameOver Int -- Final score These states form a loop, once you reach GameOver you can go back to Rea…

Elm-Action - Update your Model using a State Machine

As your Elm project gets bigger, you start having multiple pages, all with their model/update/view. Setting up your main update function to pass the Msg to the correct page and then convert the response back to a (Model,Cmd Msg) is quite tricky and from personal experience I can tell you: if you do it wrong, its very hard to read and even to refactor. Today I present to you to an out-of-the-box solution that even prevents you from writing wrong or dead code. https://package.elm-lang.org/package…