Safe Haskell	None
Language	Haskell2010

Data.Maybe.Optics

Description

This module defines Prism s for the constructors of the Maybe datatype.

Synopsis

_Nothing :: Prism' ( Maybe a) ()
_Just :: Prism ( Maybe a) ( Maybe b) a b
(%?) :: ( AppendIndices is js ks, JoinKinds k A_Prism k', JoinKinds k' l m) => Optic k is s t ( Maybe u) ( Maybe v) -> Optic l js u v a b -> Optic m ks s t a b

Documentation

A Prism that matches on the Nothing constructor of Maybe .

A Prism that matches on the Just constructor of Maybe .

(%?) :: ( AppendIndices is js ks, JoinKinds k A_Prism k', JoinKinds k' l m) => Optic k is s t ( Maybe u) ( Maybe v) -> Optic l js u v a b -> Optic m ks s t a b infixl 9 Source #

Shortcut for % _Just % .

Useful for composing lenses of Maybe type.

Since: 0.4.1