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{-# LANGUAGE UndecidableInstances #-}
module T9892 where
import Control.Applicative
import Control.Category
import Prelude hiding ((.),id)
newtype FocusingPlus w k s a = FocusingPlus { unfocusingPlus :: k (s, w) a }
instance Functor (k (s, w)) => Functor (FocusingPlus w k s) where
fmap f (FocusingPlus as) = FocusingPlus (fmap f as)
instance Applicative (k (s, w)) => Applicative (FocusingPlus w k s) where
pure = FocusingPlus . pure
FocusingPlus kf <*> FocusingPlus ka = FocusingPlus (kf <*> ka)
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