That's an interesting anecdote. I'm curious to know though, did Haskell's advanced type system help out at all? Like the various not-quite-IO monads such as S

That's an interesting anecdote. I'm curious to know though, did Haskell's advanced type system help out at all? Like the various not-quite-IO monads such as State, Reader, Writer? Or other instances of HKTs such as Functor or Applicative? Did it force you to think about the problem any differently? Or was the only real benefit just the assurance that you weren't accidentally doing IO/mutation unnecessarily?