optics-core- Optics as an abstract interface: core definitions

Safe HaskellNone



This module defines optics for constructing and manipulating finite IntSets.



members :: Fold IntSet Int Source #

IntSet isn't Foldable, but this Fold can be used to access the members of an IntSet.

>>> sumOf members $ setOf folded [1,2,3,4]

setmapped :: Setter' IntSet Int Source #

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

Sadly, you can't create a valid Traversal for an IntSet, 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 => Optic' k is s Int -> s -> IntSet Source #

Construct an IntSet from a fold.

>>> setOf folded [1,2,3,4]
fromList [1,2,3,4]
>>> setOf (folded % _2) [("hello",1),("world",2),("!!!",3)]
fromList [1,2,3]