thepratt

    data Demon = { ... }

    data Action
      = Dead
      | KnockedBack
      | Polymorphed

    class Character a where
      health :: Int

    class (Character a) => Movement a where
      speed :: Int

    class (Character a) => Enemy a where
      kill :: a -> Action
      damage :: a -> Action

    instance Character Demon where
      health = 30

    instance Movement Demon where
      speed = 5

    instance Enemy Demon where
      kill _ = _
      damage _ = _