Safe Haskell	None
Language	Haskell2010

Optics.Empty.Core

Description

This module defines the AsEmpty class, which provides a Prism for a type that may be _Empty .

Note that orphan instances for this class are defined in the Optics.Empty module from optics-extra , so if you are not simply depending on optics you may wish to import that module instead.

>>> isn't _Empty [1,2,3]
True

>>> case Nothing of { Empty -> True; _ -> False }
True

Synopsis

class AsEmpty a where
- _Empty :: Prism' a ()
pattern Empty :: forall a. AsEmpty a => a

Documentation

class AsEmpty a where Source #

Class for types that may be _Empty .

Minimal complete definition

Nothing

Methods

_Empty :: Prism' a () Source #

>>> isn't _Empty [1,2,3]
True

default _Empty :: ( Monoid a, Eq a) => Prism' a () Source #

Instances

Instances details

AsEmpty Ordering Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' Ordering () Source #
AsEmpty () Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' () () Source #
AsEmpty Event Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' Event () Source #
AsEmpty All Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' All () Source #
AsEmpty Any Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' Any () Source #
AsEmpty IntSet Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' IntSet () Source #
AsEmpty [a] Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' [a] () Source #
AsEmpty ( Maybe a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Maybe a) () Source #
AsEmpty ( ZipList a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( ZipList a) () Source #
AsEmpty ( First a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( First a) () Source #
AsEmpty ( Last a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Last a) () Source #
AsEmpty a => AsEmpty ( Dual a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Dual a) () Source #
( Eq a, Num a) => AsEmpty ( Sum a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Sum a) () Source #
( Eq a, Num a) => AsEmpty ( Product a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Product a) () Source #
AsEmpty ( IntMap a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( IntMap a) () Source #
AsEmpty ( Seq a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Seq a) () Source #
AsEmpty ( Set a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Set a) () Source #
( AsEmpty a, AsEmpty b) => AsEmpty (a, b) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' (a, b) () Source #
AsEmpty ( Map k a) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' ( Map k a) () Source #
( AsEmpty a, AsEmpty b, AsEmpty c) => AsEmpty (a, b, c) Source #
Instance details Defined in Optics.Empty.Core Methods _Empty :: Prism' (a, b, c) () Source #

pattern Empty :: forall a. AsEmpty a => a Source #

Pattern synonym for matching on any type with an AsEmpty instance.

>>> case Nothing of { Empty -> True; _ -> False }
True