1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
|
(*
* Copyright (C) 2006-2009 Citrix Systems Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; version 2.1 only. with the special
* exception on linking described in file LICENSE.
*
* 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 Lesser General Public License for more details.
*)
(* Perhaps it's better to use `option' from the ocaml-extlib extension
* to the standard library instead? (Although it would not suffice,
* since it's not a super-set of our `opt'.)
* (http://code.google.com/p/ocaml-extlib/)
*)
open Pervasiveext
module Monad = Monad.M1.Make (struct
type 'a m = 'a option
let bind option f =
match option with
| None -> None
| Some result -> f result
let return x = Some x
end)
let iter f = function
| Some x -> f x
| None -> ()
let map f = function
| Some x -> Some(f x)
| None -> None
let default d = function
| Some x -> x
| None -> d
let unbox = function
| Some x -> x
| None -> raise Not_found
let is_boxed = function
| Some _ -> true
| None -> false
let to_list = function
| Some x -> [x]
| None -> []
let fold_left f accu = function
| Some x -> f accu x
| None -> accu
let fold_right f opt accu =
match opt with
| Some x -> f x accu
| None -> accu
let join = function
| Some (Some a) -> Some a
| _ -> None
let of_exception f =
try Some (f ())
with _ -> None
|
