map -package:unordered-containers -package:containers -package:ghc -package:integration -package:base-prelude -package:Cabal-syntax package:insert-ordered-containers
Order preserving mapping of keys.
HashMap which tries its best to remember insertion order of
elements.
This is a slight lie, as roundtrip doesn't preserve ordering.
More efficient than
foldMap, when folding in insertion order is
not important.
More efficient than
foldMapWithKey, when folding in insertion
order is not important.