Data.IntSet.Lens

Documentation

contains :: Int -> Simple Lens IntSet Bool

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

 ghci> contains 3 +~ False $ fromList [1,2,3,4]
 fromList [1,2,4]

 contains :: Int -> (Bool -> f Bool) -> IntSet -> f IntSet

members :: Setter IntSet IntSet Int Int

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

Sadly, you can't create a valid Traversal for a Set, because the number of elements might change but you can manipulate it by reading using folded and reindexing it via setmap.

 ghci> adjust members (+1) (fromList [1,2,3,4]
 fromList [2,3,4,5]