optics-extra-0.2: Extra utilities and instances for optics-core

Safe HaskellNone



This module defines optics for constructing and manipulating finite HashSets.



setmapped :: (Eq b, Hashable b) => Setter (HashSet a) (HashSet b) a b Source #

This Setter can be used to change the type of a HashSet by mapping the elements to new values.

Sadly, you can't create a valid Traversal for a HashSet, but you can manipulate it by reading using folded and reindexing it via setmapped.

>>> over setmapped (+1) (fromList [1,2,3,4])
fromList [2,3,4,5]

setOf :: (Is k A_Fold, Eq a, Hashable a) => Optic' k is s a -> s -> HashSet a Source #

Construct a HashSet from a fold.

>>> setOf folded ["hello","world"]
fromList ["hello","world"]
>>> setOf (folded % _2) [("hello",1),("world",2),("!!!",3)]
fromList [1,2,3]