(*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*)
(** Performs a map, but returns the original optional if there is no change **)
let ident_map f x =
match x with
| None -> x
| Some x' ->
let x'' = f x' in
if x'' == x' then
x
else
Some x''