I implemented <a href="https:&#x2F;&#x2F;threegoodthings.xyz&#x2F;" rel="nofollow">https:&#x2F;&#x2F;threegoodthings.xyz&#x2F;</a> in Haskell (code: <a href="https:&#x2F;&#x2F;github.com&#x2F;thedufer&#x2F;threegoodhaskells" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;thedufer&#x2F;threegoodhaskells</a>).  It took longer (although be less than I expected) than my first implementation, and the type system has cut down on bugs by a lot when I add new features.  The lack of libraries for things that I&#x27;d expect to be easy has been a bit of a pain occasionally, though.