val let+ : ('a, 'b) Stdlib.result -> ('a -> 'c) -> ('c, 'b) Stdlib.result
val let* :
('a, 'b) Stdlib.result ->
('a -> ('c, 'b) Stdlib.result) ->
('c, 'b) Stdlib.result
val let- :
('a, 'b) Stdlib.result ->
('b -> ('a, 'c) Stdlib.result) ->
('a, 'c) Stdlib.result