Driver.Cookiesval get : 
  t ->
  string ->
  (Astlib.Ast_500.Parsetree.expression, 'a -> 'a, 'b) Ast_pattern.t ->
  'b optionget cookies name pattern look for a cookie named name and parse it using pattern. Raises if the parsing fails.
val get_res : 
  t ->
  string ->
  (Astlib.Ast_500.Parsetree.expression, 'a -> 'a, 'b) Ast_pattern.t ->
  ('b option, Location.Error.t Stdppx.NonEmptyList.t) resultget cookies name pattern look for a cookie named name and parse it using pattern, returning a result instead of raising when the parsing fails.
val set : t -> string -> Astlib.Ast_500.Parsetree.expression -> unitset cookies name expr set cookie name to expr.
val add_handler : (t -> unit) -> unitRegister a callback that is called before a rewriting. The handler is expected to lookup some cookies and set some global variables.
This API is a temporary hack to allow to migrate from add_arg to the use of cookie, until ppxlib has been upgraded to pass cookies through.
val add_simple_handler : 
  string ->
  (Astlib.Ast_500.Parsetree.expression, 'a -> 'a, 'b) Ast_pattern.t ->
  f:('b option -> unit) ->
  unitShorthand for: add_handler (fun t -> f (get t name pattern))
val add_post_handler : (t -> unit) -> unitRegister a callback that is called after a rewriting. The handler is expected to set some cookies from some global variables.