shithub: MicroHs

ref: 924f18d2d6cc10dbfa191a710e274bb6660ea50a
dir: /lib/Control/Monad/ST.hs/

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module Control.Monad.ST(
  ST,
  runST,
  ) where
import Prelude
import Primitives(primPerformIO)
import Control.Monad.ST_Type

runST :: forall a . (forall s . ST s a) -> a
runST (ST ioa) = primPerformIO ioa

instance forall s . Functor (ST s) where
  fmap f (ST x) = ST (fmap f x)

instance forall s . Applicative (ST s) where
  pure x = ST (pure x)
  ST x <*> ST y = ST (x <*> y)

instance forall s . Monad (ST s) where
  ST x >>= f = ST (x >>= (unST . f))