This Setter
can be used to change the type of a Set
by mapping
the elements to new values.
Sadly, you can't create a valid Traversal
for a Set
, 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]