-- version if desired.
second :: a b c -> a (d,b) (d,c)
second f = arr swap >>> first f >>> arr swap
- where swap ~(x,y) = (y,x)
+ where swap :: (x,y) -> (y,x)
+ swap ~(x,y) = (y,x)
-- | Split the input between the two argument arrows and combine
-- their output. Note that this is in general not a functor.
-- version if desired.
right :: a b c -> a (Either d b) (Either d c)
right f = arr mirror >>> left f >>> arr mirror
- where mirror (Left x) = Right x
+ where mirror :: Either x y -> Either y x
+ mirror (Left x) = Right x
mirror (Right y) = Left y
-- | Split the input between the two argument arrows, retagging