--

---------------------------------------------------------
---------------------------------------------------------
-- Todo

-- | A lens focusing on the first element in a pair
-- f :: a -> Functor b
-- g :: (a, x) -> Functor (b, x)
_1 :: Lens (a, x) (b, x) a b
_1 f (a, x) = (, x) <$> f a
_1 :: Lens (a, x) (b, x) a b
_1 f (a, x) = (, x) <$> f a
_1 f (a, x) = (, x) <$> f a