unto f # x ≡ f x l # x ≡ x ^. re lThis is commonly used when using a Prism as a smart constructor.
>>> _Left # 4 Left 4But it can be used for any Prism
>>> base 16 # 123 "7b"
(#) :: Iso' s a -> a -> s (#) :: Prism' s a -> a -> s (#) :: Review s a -> a -> s (#) :: Equality' s a -> a -> s