Class.purs

module Hyper.Middleware.Class where

import Control.Monad.Indexed (class IxMonad, (:>>=))
import Data.Unit (Unit)

class IxMonadMiddleware m where
  getConn ∷ ∀ i. m i i i
  putConn ∷ ∀ i o. o → m i o Unit

modifyConn ∷ ∀ m i o
  .  IxMonad m
  => IxMonadMiddleware m
  => (i → o) -> m i o Unit
modifyConn f = getConn :>>= \c -> putConn (f c)