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GHC 9.14.1 · lts/ghc-9.14.x · 45dd537 · 2026-10-11

Moduleoptics-core-0.4.2Haskell2010

Data.Maybe.Optics

This module defines Prisms for the constructors of the Maybe datatype.

3 values

Packageoptics-core-0.4.2
Exports3
LanguageHaskell2010
LicenceBSD-3-Clause
SourceOptics.hs

value_Nothing :: Prism' (Maybe a) ()

A Prism that matches on the Nothing constructor of Maybe.

value_Just :: Prism (Maybe a) (Maybe b) a b

A Prism that matches on the Just constructor of Maybe.

value(%?)

:: (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

Shortcut for % _Just %.

Useful for composing lenses of Maybe type.