Control.Lens.Internal.SemiIso

Documentation

data Barter s t a b

Type used internally to access SemiIso.

Continues the naming tradition of lens.

Constructors

Barter (a -> Either String s) (t -> Either String b)

Instances

Profunctor (Barter s t)

Choice (Barter s t)

Failure (Barter s t)

class Profunctor p => Failure p where

Provides a profunctor the ability to fail with an error message.

This class could use some laws. It is certainly a bit ad-hoc.

Methods

tie :: p a (Either String b) -> p a b

attach :: p a b -> p (Either String a) b

Instances

Failure (Barter s t)