(* 
 * CoqUp: Verified high-level synthesis.
 * Copyright (C) 2019-2020 Yann Herklotz <yann@yannherklotz.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *)

Module Option.

Definition default {T : Type} (x : T) (u : option T) : T :=
  match u with
  | Some y => y
  | _ => x
  end.

Definition map {S : Type} {T : Type} (f : S -> T) (u : option S) : option T :=
  match u with
  | Some y => Some (f y)
  | _ => None
  end.

Definition liftA2 {T : Type} (f : T -> T -> T) (a : option T) (b : option T) : option T :=
  match a with
  | Some x => map (f x) b
  | _ => None
  end.

End Option.