A ReversedPrism is a backwards Prism, i.e. a ReversedPrism s t a b is equivalent to a Prism b a t s. These are typically produced by calling re on a Prism. They are distinguished from a Getter so that re . re on a Prism returns a Prism.

There is no canonical introduction form for ReversedPrism, but you can use re to construct one from a Prism:

(\ f g -> re (prism f g)) :: (s -> a) -> (b -> Either a t) -> ReversedPrism s t a b

A ReversedPrism is a Getter, so you can specialise types to obtain:

view :: ReversedPrism' s a -> s -> a

There is no reversed matching defined, but it is definable using re:

matching . re :: ReversedPrism s t a b -> b -> Either a t

view          $ re (prism f g) ≡ f
matching . re $ re (prism f g) ≡ g