option.ml

(*
 * Chibisat - a tiny DPLL based SAT Solver 
 * Copyright (c) 2013 Takahisa Watanabe <linerlock@outlook.com> All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *)

exception No_value of string

type 'a t = 'a option

let is_some x =
  match x with
    Some _ -> true
  | None   -> false
    
let is_none x =
  match x with
    Some _ -> false
  | None   -> true
    
let get x =
  match x with
    Some x -> x
  | None   -> raise (No_value "None")
    
let map f x =
  match x with
    Some v -> Some (f v)
  | None   -> None

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