aboutsummaryrefslogtreecommitdiffhomepage
path: root/lib/iStream.ml
blob: c9f4d4a111be643578ce48d54b962ff91787f63e (plain)
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
77
78
79
80
81
82
83
84
85
86
87
88
89
90
(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, *   INRIA - CNRS - LIX - LRI - PPS - Copyright 1999-2016     *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

type ('a,'r) u =
| Nil
| Cons of 'a * 'r

type 'a node = ('a,'a t) u

and 'a t = 'a node Lazy.t

let empty = Lazy.lazy_from_val Nil

let cons x s = Lazy.lazy_from_val (Cons (x, s))

let thunk = Lazy.lazy_from_fun

let rec make_node f s = match f s with
| Nil -> Nil
| Cons (x, s) -> Cons (x, make f s)

and make f s = lazy (make_node f s)

let rec force s = match Lazy.force s with
| Nil -> ()
| Cons (_, s) -> force s

let force s = force s; s

let is_empty s = match Lazy.force s with
| Nil -> true
| Cons (_, _) -> false

let peek = Lazy.force

let rec of_list = function
| [] -> empty
| x :: l -> cons x (of_list l)

let rec to_list s = match Lazy.force s with
| Nil -> []
| Cons (x, s) -> x :: (to_list s)

let rec iter f s = match Lazy.force s with
| Nil -> ()
| Cons (x, s) -> f x; iter f s

let rec map_node f = function
| Nil -> Nil
| Cons (x, s) -> Cons (f x, map f s)

and map f s = lazy (map_node f (Lazy.force s))

let rec app_node n1 s2 = match n1 with
| Nil -> Lazy.force s2
| Cons (x, s1) -> Cons (x, app s1 s2)

and app s1 s2 = lazy (app_node (Lazy.force s1) s2)

let rec fold f accu s = match Lazy.force s with
| Nil -> accu
| Cons (x, s) -> fold f (f accu x) s

let rec map_filter_node f = function
| Nil -> Nil
| Cons (x, s) ->
  begin match f x with
  | None -> map_filter_node f (Lazy.force s)
  | Some y -> Cons (y, map_filter f s)
  end

and map_filter f s = lazy (map_filter_node f (Lazy.force s))

let rec concat_node = function
| Nil -> Nil
| Cons (s, sl) -> app_node (Lazy.force s) (concat sl)

and concat (s : 'a t t) =
  lazy (concat_node (Lazy.force s))

let rec concat_map_node f = function
| Nil -> Nil
| Cons (x,s) -> app_node (Lazy.force (f x)) (concat_map f s)

and concat_map f l = lazy (concat_map_node f (Lazy.force l))