aboutsummaryrefslogtreecommitdiffhomepage
path: root/lib/util.ml
blob: 7d7d380b262be951c2de7720ac40ab292b2c51ec (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
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
(************************************************************************)
(*         *   The Coq Proof Assistant / The Coq Development Team       *)
(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
(* <O___,, *       (see CREDITS file for the list of authors)           *)
(*   \VV/  **************************************************************)
(*    //   *    This file is distributed under the terms of the         *)
(*         *     GNU Lesser General Public License Version 2.1          *)
(*         *     (see LICENSE file for the text of the license)         *)
(************************************************************************)

(* Mapping under pairs *)

let on_fst f (a,b) = (f a,b)
let on_snd f (a,b) = (a,f b)
let map_pair f (a,b) = (f a,f b)

(* Mapping under pairs *)

let on_pi1 f (a,b,c) = (f a,b,c)
let on_pi2 f (a,b,c) = (a,f b,c)
let on_pi3 f (a,b,c) = (a,b,f c)

(* Projections from triplets *)

let pi1 (a,_,_) = a
let pi2 (_,a,_) = a
let pi3 (_,_,a) = a

(* Characters *)

let is_letter c = (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
let is_digit c = (c >= '0' && c <= '9')
let is_ident_tail c =
  is_letter c || is_digit c || c = '\'' || c = '_'
let is_blank = function
  | ' ' | '\r' | '\t' | '\n' -> true
  | _ -> false

module Empty =
struct
  type t
  let abort (x : t) = assert false
end

(* Strings *)

module String : CString.ExtS = CString

let subst_command_placeholder s t =
  let buff = Buffer.create (String.length s + String.length t) in
  let i = ref 0 in
  while (!i < String.length s) do
    if s.[!i] = '%' && !i+1 < String.length s && s.[!i+1] = 's'
    then (Buffer.add_string buff t;incr i)
    else Buffer.add_char buff s.[!i];
    incr i
  done;
  Buffer.contents buff

(* Lists *)

module List : CList.ExtS = CList

let (@) = CList.append

(* Arrays *)

module Array : CArray.ExtS = CArray

(* Sets *)

module Set = CSet

(* Maps *)

module Map = CMap

(* Stacks *)

module Stack = CStack

(* Matrices *)

let matrix_transpose mat =
  List.fold_right (List.map2 (fun p c -> p::c)) mat
    (if List.is_empty mat then [] else List.map (fun _ -> []) (List.hd mat))

(* Functions *)

let identity x = x

(** Left-to-right function composition:
    
    [f1 %> f2] is [fun x -> f2 (f1 x)].

    [f1 %> f2 %> f3] is [fun x -> f3 (f2 (f1 x))].

    [f1 %> f2 %> f3 %> f4] is [fun x -> f4 (f3 (f2 (f1 x)))]

    etc.
*)
let (%>) f g x = g (f x)

let const x _ = x

let iterate =
  let rec iterate_f f n x =
    if n <= 0 then x else iterate_f f (pred n) (f x)
  in
  iterate_f

let repeat n f x =
  let rec loop i = if i <> 0 then (f x; loop (i - 1)) in loop n

let app_opt f x =
  match f with
  | Some f -> f x
  | None -> x

(* Stream *)

let stream_nth n st =
  try List.nth (Stream.npeek (n+1) st) n
  with Failure _ -> raise Stream.Failure

let stream_njunk n st =
  repeat n Stream.junk st

(* Delayed computations *)

type 'a delayed = unit -> 'a

let delayed_force f = f ()

(* Misc *)

type ('a, 'b) union = ('a, 'b) CSig.union = Inl of 'a | Inr of 'b
type 'a until = 'a CSig.until = Stop of 'a | Cont of 'a
type ('a, 'b) eq = ('a, 'b) CSig.eq = Refl : ('a, 'a) eq

let sym : type a b. (a, b) eq -> (b, a) eq = fun Refl -> Refl

module Union =
struct
  let map f g = function
    | Inl a -> Inl (f a)
    | Inr b -> Inr (g b)

  (** Lifting equality onto union types. *)
  let equal f g x y = match x, y with
    | Inl x, Inl y -> f x y
    | Inr x, Inr y -> g x y
    | _, _ -> false

  let fold_left f g a = function
    | Inl y -> f a y
    | Inr y -> g a y
end

let map_union = Union.map

type iexn = Exninfo.iexn

let iraise = Exninfo.iraise

let open_utf8_file_in fname =
  let is_bom s =
    Int.equal (Char.code (Bytes.get s 0)) 0xEF &&
    Int.equal (Char.code (Bytes.get s 1)) 0xBB &&
    Int.equal (Char.code (Bytes.get s 2)) 0xBF
  in
  let in_chan = open_in fname in
  let s = Bytes.make 3 ' ' in
  if input in_chan s 0 3 < 3 || not (is_bom s) then seek_in in_chan 0;
  in_chan

(** A trick which can typically be used to store on the fly the
   computation of values in the "when" clause of a "match" then
   retrieve the evaluated result in the r.h.s of the clause *)

let set_temporary_memory () =
  let a = ref None in
  (fun x -> assert (!a = None); a := Some x; x),
  (fun () -> match !a with Some x -> x | None -> assert false)