What Is Good About Haskell?
Haskell is a beautiful research language. Its usecase is to supply subjects for PhDs and MScs, which it fulfills perfectly. Also it&#x27;s extremely fun to learn and play with.<p>I would never bring it to the production though, reasons being:<p>1) Production code should be understandable by an on-call person at 4 am. If business logic is buried under layers of lenses, monad transformers and arrows, good luck troubleshooting it under stress. And real systems do break, no matter type safety.<p>2) It&#x27;s a research language, and a big part of the research is about control flow. And therefore haskell has _way too many_ ways to combine things: monad transformers of different flavors, applicative functors, arrows, iteratees, you name it. And libraries you find on hackage choose _different_ ways to combine things. In the business code you probably want to combine multiple libraries, and you inevitably end up with unholy mess of all these approaches. Dealing with it takes more time than writing business logic.<p>3) Developers look at these fancy research papers and try to reproduce them. As a result, very basic things become extremely hard and brittle. I saw a real-live example when applying a transform to all fields of a record took a team 2 days of discussion in slack, because &quot;writing this manually?! it won&#x27;t scale to record with 100 fields&quot;.<p>4) Architecture is extremely sensitive to the initial choices due to isolation of side effects. Because if you suddenly need to do something as simple as logging or reading a config in a place where it wasn&#x27;t originally anticipated, you&#x27;re in for a bumpy ride.