lens-1.1: Families of Lenses, Folds and Traversals

Portabilityportable
Stabilityprovisional
MaintainerEdward Kmett <ekmett@gmail.com>
Safe HaskellSafe-Infered

Data.Set.Lens

Description

 

Synopsis

Documentation

contains :: Ord k => k -> Simple Lens (Set k) BoolSource

This Lens can be used to read, write or delete a member of a Set

 ghci> contains 3 +~ False $ Set.fromList [1,2,3,4]
 fromList [1,2,4]
 contains :: Ord k => k -> (Bool -> f Bool) -> Set k -> f (Set k)