module Control.Lens.Internal.Prism
( Market(..)
, Market'
) where
import Data.Profunctor
#ifndef SAFE
import Data.Profunctor.Unsafe
import Control.Lens.Internal.Coerce
#endif
data Market a b s t = Market (b -> t) (s -> Either t a)
type Market' a = Market a a
instance Functor (Market a b s) where
fmap f (Market bt seta) = Market (f . bt) (either (Left . f) Right . seta)
instance Profunctor (Market a b) where
dimap f g (Market bt seta) = Market (g . bt) (either (Left . g) Right . seta . f)
lmap f (Market bt seta) = Market bt (seta . f)
rmap f (Market bt seta) = Market (f . bt) (either (Left . f) Right . seta)
#ifndef SAFE
( #. ) _ = coerce'
( .# ) p _ = coerce p
#endif
instance Choice (Market a b) where
left' (Market bt seta) = Market (Left . bt) $ \sc -> case sc of
Left s -> case seta s of
Left t -> Left (Left t)
Right a -> Right a
Right c -> Left (Right c)
right' (Market bt seta) = Market (Right . bt) $ \cs -> case cs of
Left c -> Left (Left c)
Right s -> case seta s of
Left t -> Left (Right t)
Right a -> Right a