#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
#endif
module Control.Comonad.Store.Class
( ComonadStore(..)
, lowerPos
, lowerPeek
) where
import Control.Comonad
import Control.Comonad.Trans.Class
import Control.Comonad.Trans.Env
import qualified Control.Comonad.Trans.Store as Store
import Control.Comonad.Trans.Traced
import Control.Comonad.Trans.Identity
#if __GLASGOW_HASKELL__ < 710
import Data.Semigroup
#endif
class Comonad w => ComonadStore s w | w -> s where
pos :: w a -> s
peek :: s -> w a -> a
peeks :: (s -> s) -> w a -> a
peeks f w = peek (f (pos w)) w
seek :: s -> w a -> w a
seek s = peek s . duplicate
seeks :: (s -> s) -> w a -> w a
seeks f = peeks f . duplicate
experiment :: Functor f => (s -> f s) -> w a -> f a
experiment f w = fmap (`peek` w) (f (pos w))
instance Comonad w => ComonadStore s (Store.StoreT s w) where
pos = Store.pos
peek = Store.peek
peeks = Store.peeks
seek = Store.seek
seeks = Store.seeks
experiment = Store.experiment
lowerPos :: (ComonadTrans t, ComonadStore s w) => t w a -> s
lowerPos = pos . lower
lowerPeek :: (ComonadTrans t, ComonadStore s w) => s -> t w a -> a
lowerPeek s = peek s . lower
lowerExperiment :: (ComonadTrans t, ComonadStore s w, Functor f) => (s -> f s) -> t w a -> f a
lowerExperiment f = experiment f . lower
instance ComonadStore s w => ComonadStore s (IdentityT w) where
pos = lowerPos
peek = lowerPeek
experiment = lowerExperiment
instance ComonadStore s w => ComonadStore s (EnvT e w) where
pos = lowerPos
peek = lowerPeek
experiment = lowerExperiment
instance (ComonadStore s w, Monoid m) => ComonadStore s (TracedT m w) where
pos = lowerPos
peek = lowerPeek
experiment = lowerExperiment