danstn

-- | simple/basic Scala -> Haskell translation of Runar's presentation
-- | (https://dl.dropboxusercontent.com/u/4588997/ReasonablyPriced.pdf)
-- | trying to use minimal extensions and magic. 
-- | (earlier I had a version using MultiParamTypeClasses for Runar's
-- | Inject class, but scraped it opting for simplicity)
-- | my question: what do we lose by moving towards simplicity?
-- | Future work: use DataKinds, TypeOperators, and potentially TypeFamilies
-- | to maintain and automate the folding of types in Coproduct.

{-# LANGUAGE Rank2Types, DeriveFunctor #-}

danstn

sealed trait Interact[A]

case class Ask(prompt: String)
  extends Interact[String]

case class Tell(msg: String)
  extends Interact[Unit]

trait Monad[M[_]] {
  def pure[A](a: A): M[A]