(******************************************************************************)
(*                                                                            *)
(*                                   Menhir                                   *)
(*                                                                            *)
(*                       François Pottier, Inria Paris                        *)
(*              Yann Régis-Gianas, PPS, Université Paris Diderot              *)
(*                                                                            *)
(*  Copyright Inria. All rights reserved. This file is distributed under the  *)
(*  terms of the GNU General Public License version 2, as described in the    *)
(*  file LICENSE.                                                             *)
(*                                                                            *)
(******************************************************************************)

let map f = function
  | None ->
      None
  | Some x ->
      Some (f x)

let iter f o =
  match o with
  | None ->
      ()
  | Some x ->
      f x

let fold f o accu =
  match o with
  | None ->
      accu
  | Some x ->
      f x accu

let project = function
  | Some x ->
      x
  | None ->
      (* Presumably, an error message has already been printed. *)
      exit 1

let equal equal o1 o2 =
  match o1, o2 with
  | None, None ->
      true
  | Some x1, Some x2 ->
      equal x1 x2
  | None, Some _
  | Some _, None ->
      false

let hash hash = function
  | Some x ->
      hash x
  | None ->
      Hashtbl.hash None
