summaryrefslogtreecommitdiff
path: root/lib/util.ml
blob: 2e6e12791cb9789cf18e4803ed8fc27e255d4973 (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
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
(***********************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team    *)
(* <O___,, *        INRIA-Rocquencourt  &  LRI-CNRS-Orsay              *)
(*   \VV/  *************************************************************)
(*    //   *      This file is distributed under the terms of the      *)
(*         *       GNU Lesser General Public License Version 2.1       *)
(***********************************************************************)

(* $Id: util.ml 8672 2006-03-29 21:06:33Z herbelin $ *)

open Pp

(* Errors *)

exception Anomaly of string * std_ppcmds  (* System errors *)
let anomaly string = raise (Anomaly(string, str string))
let anomalylabstrm string pps = raise (Anomaly(string,pps))

exception UserError of string * std_ppcmds (* User errors *)
let error string = raise (UserError(string, str string))
let errorlabstrm l pps = raise (UserError(l,pps))

let todo s = prerr_string ("TODO: "^s^"\n")

type loc = Compat.loc
let dummy_loc = Compat.dummy_loc
let unloc = Compat.unloc
let make_loc = Compat.make_loc

(* raising located exceptions *)
type 'a located = loc * 'a
let anomaly_loc (loc,s,strm) = Stdpp.raise_with_loc loc (Anomaly (s,strm))
let user_err_loc (loc,s,strm) = Stdpp.raise_with_loc loc (UserError (s,strm))
let invalid_arg_loc (loc,s) = Stdpp.raise_with_loc loc (Invalid_argument s)
let join_loc loc1 loc2 =
  if loc1 = dummy_loc or loc2 = dummy_loc then dummy_loc
  else (fst loc1, snd loc2)

(* Like Exc_located, but specifies the outermost file read, the filename
   associated to the location of the error, and the error itself. *)

exception Error_in_file of string * (bool * string * loc) * exn

(* Projections from triplets *)

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

(* Characters *)

let is_letter c =
  (c >= 'a' && c <= 'z') or
  (c >= 'A' && c <= 'Z') or
  (c >= '\248' && c <= '\255') or
  (c >= '\192' && c <= '\214') or
  (c >= '\216' && c <= '\246')

let is_digit c = (c >= '0' && c <= '9')

let is_ident_tail c =
  is_letter c or is_digit c or c = '\'' or c = '_'

(* Strings *)

let explode s = 
  let rec explode_rec n =
    if n >= String.length s then
      []
    else 
      String.make 1 (String.get s n) :: explode_rec (succ n)
  in 
  explode_rec 0

let implode sl = String.concat "" sl

(* substring searching... *)

(* gdzie = where, co = what *)
(* gdzie=gdzie(string) gl=gdzie(length) gi=gdzie(index) *)
let rec is_sub gdzie gl gi co cl ci = 
  (ci>=cl) ||
  ((String.unsafe_get gdzie gi = String.unsafe_get co ci) && 
   (is_sub gdzie gl (gi+1) co cl (ci+1)))

let rec raw_str_index i gdzie l c co cl = 
  let i' = String.index_from gdzie i c in
    if (i'+cl <= l) && (is_sub gdzie l i' co cl 0) then i' else
      raw_str_index (i'+1) gdzie l c co cl

let string_index_from gdzie i co = 
  if co="" then i else
    raw_str_index i gdzie (String.length gdzie)
      (String.unsafe_get co 0) co (String.length co)

let string_string_contains ~where ~what =
  try
    let _ = string_index_from where 0 what in true
  with
      Not_found -> false

let plural n s = if n>1 then s^"s" else s

(* string parsing *)

let parse_loadpath s =
  let len = String.length s in
  let rec decoupe_dirs n =
    try  
      let pos = String.index_from s n '/' in
      if pos = n then
	invalid_arg "parse_loadpath: find an empty dir in loadpath";
      let dir = String.sub s n (pos-n) in
      dir :: (decoupe_dirs (succ pos))
    with
      | Not_found -> [String.sub s n (len-n)]
  in
  if len = 0 then [] else decoupe_dirs 0

module Stringset = Set.Make(struct type t = string let compare = compare end)

module Stringmap = Map.Make(struct type t = string let compare = compare end)

(* Lists *)

let list_add_set x l = if List.mem x l then l else x::l

let list_intersect l1 l2 = 
  List.filter (fun x -> List.mem x l2) l1

let list_union l1 l2 = 
  let rec urec = function
    | [] -> l2
    | a::l -> if List.mem a l2 then urec l else a::urec l
  in 
  urec l1

let list_unionq l1 l2 = 
  let rec urec = function
    | [] -> l2
    | a::l -> if List.memq a l2 then urec l else a::urec l
  in 
  urec l1

let list_subtract l1 l2 =
  if l2 = [] then l1 else List.filter (fun x -> not (List.mem x l2)) l1

let list_subtractq l1 l2 = 
  if l2 = [] then l1 else List.filter (fun x -> not (List.memq x l2)) l1

let list_chop n l = 
  let rec chop_aux acc = function
    | (0, l2) -> (List.rev acc, l2)
    | (n, (h::t)) -> chop_aux (h::acc) (pred n, t)
    | (_, []) -> failwith "list_chop"
  in 
  chop_aux [] (n,l)

let list_tabulate f len = 
  let rec tabrec n =
    if n = len then [] else (f n)::(tabrec (n+1))
  in 
  tabrec 0

let list_assign l n e = 
  let rec assrec stk = function
    | ((h::t), 0) -> List.rev_append stk (e::t)
    | ((h::t), n) -> assrec (h::stk) (t, n-1)
    | ([], _) -> failwith "list_assign"
  in 
  assrec [] (l,n)

let rec list_smartmap f l = match l with
    [] -> l
  | h::tl -> 
      let h' = f h and tl' = list_smartmap f tl in
	if h'==h && tl'==tl then l
	else h'::tl'

let list_map_left f = (* ensures the order in case of side-effects *)
  let rec map_rec = function
    | [] -> [] 
    | x::l -> let v = f x in v :: map_rec l
  in 
  map_rec

let list_map_i f = 
  let rec map_i_rec i = function
    | [] -> [] 
    | x::l -> let v = f i x in v :: map_i_rec (i+1) l
  in 
  map_i_rec

let list_map2_i f i l1 l2 =  
  let rec map_i i = function
    | ([], []) -> []
    | ((h1::t1), (h2::t2)) -> (f i h1 h2) :: (map_i (succ i) (t1,t2))
    | (_, _) -> invalid_arg "map2_i"
  in 
  map_i i (l1,l2)

let list_map3 f l1 l2 l3 =
  let rec map = function
    | ([], [], []) -> []
    | ((h1::t1), (h2::t2), (h3::t3)) -> (f h1 h2 h3) :: (map (t1,t2,t3))
    | (_, _, _) -> invalid_arg "map3"
  in 
  map (l1,l2,l3)

let list_index x = 
  let rec index_x n = function
    | y::l -> if x = y then n else index_x (succ n) l
    | [] -> raise Not_found
  in 
  index_x 1

let list_fold_left_i f = 
  let rec it_list_f i a = function
    | [] -> a 
    | b::l -> it_list_f (i+1) (f i a b) l
  in 
  it_list_f 

(* [list_fold_right_and_left f [a1;...;an] hd =
   f (f (... (f (f hd
                   an
                   [an-1;...;a1])
              an-1
              [an-2;...;a1])
         ...)
        a2
        [a1])
     a1
     []] *)

let rec list_fold_right_and_left f l hd =
  let rec aux tl = function
    | [] -> hd
    | a::l -> let hd = aux (a::tl) l in f hd a tl
   in aux [] l

let list_iter_i f l = list_fold_left_i (fun i _ x -> f i x) 0 () l

let list_for_all_i p = 
  let rec for_all_p i = function
    | [] -> true 
    | a::l -> p i a && for_all_p (i+1) l
  in 
  for_all_p

let list_except x l = List.filter (fun y -> not (x = y)) l

let list_remove = list_except (* Alias *)

let rec list_remove_first a = function
  | b::l when a = b -> l
  | b::l -> b::list_remove_first a l
  | [] -> raise Not_found

let list_for_all2eq f l1 l2 = try List.for_all2 f l1 l2 with Failure _ -> false

let list_map_i f = 
  let rec map_i_rec i = function
    | [] -> [] 
    | x::l -> let v = f i x in v::map_i_rec (i+1) l
  in 
  map_i_rec

let rec list_sep_last = function
  | [] -> failwith "sep_last"
  | hd::[] -> (hd,[])
  | hd::tl -> let (l,tl) = list_sep_last tl in (l,hd::tl)

let list_try_find_i f = 
  let rec try_find_f n = function
    | [] -> failwith "try_find_i"
    | h::t -> try f n h with Failure _ -> try_find_f (n+1) t
  in 
  try_find_f

let list_try_find f = 
  let rec try_find_f = function
    | [] -> failwith "try_find"
    | h::t -> try f h with Failure _ -> try_find_f t
  in 
  try_find_f

let rec list_uniquize = function
  | [] -> []
  | h::t -> if List.mem h t then list_uniquize t else h::(list_uniquize t)

let rec list_distinct = function
  | h::t -> (not (List.mem h t)) && list_distinct t
  | _ -> true

let rec list_filter2 f = function
  | [], [] as p -> p
  | d::dp, l::lp ->
     let (dp',lp' as p) = list_filter2 f (dp,lp) in
      if f d l then d::dp', l::lp' else p
  | _ -> invalid_arg "list_filter2"

let list_subset l1 l2 =
  let t2 = Hashtbl.create 151 in
  List.iter (fun x -> Hashtbl.add t2 x ()) l2;
  let rec look = function
    | [] -> true
    | x::ll -> try Hashtbl.find t2 x; look ll with Not_found -> false
  in 
  look l1

let list_splitby p = 
  let rec splitby_loop x y = 
    match y with 
      | []      -> ([],[])
      | (a::l)  -> if (p a) then (x,y) else (splitby_loop (x@[a]) l)
  in 
  splitby_loop []

let rec list_split3 = function
  | [] -> ([], [], [])
  | (x,y,z)::l ->
      let (rx, ry, rz) = list_split3 l in (x::rx, y::ry, z::rz)

let list_firstn n l =
  let rec aux acc = function
    | (0, l) -> List.rev acc
    | (n, (h::t)) -> aux (h::acc) (pred n, t)
    | _ -> failwith "firstn"
  in 
  aux [] (n,l)

let rec list_last = function
  | [] -> failwith "list_last"
  | [x] -> x
  | _ :: l -> list_last l

let list_lastn n l =
  let len = List.length l in
  let rec aux m l =
    if m = n then l else aux (m - 1) (List.tl l)
  in
  if len < n then failwith "lastn" else aux len l

let rec list_skipn n l = match n,l with 
  | 0, _ -> l 
  | _, [] -> failwith "list_fromn"
  | n, _::l -> list_skipn (pred n) l

let list_prefix_of prefl l = 
  let rec prefrec = function
    | (h1::t1, h2::t2) -> h1 = h2 && prefrec (t1,t2)
    | ([], _) -> true
    | (_, _) -> false
  in 
  prefrec (prefl,l)

let list_map_append f l = List.flatten (List.map f l)

let list_map_append2 f l1 l2 = List.flatten (List.map2 f l1 l2)

let list_share_tails l1 l2 =
  let rec shr_rev acc = function
    | ((x1::l1), (x2::l2)) when x1 == x2 -> shr_rev (x1::acc) (l1,l2)
    | (l1,l2) -> (List.rev l1, List.rev l2, acc)
  in 
  shr_rev [] (List.rev l1, List.rev l2)

let list_join_map f l = List.flatten (List.map f l)

let rec list_fold_map f e = function
  |  []  -> (e,[])
  |  h::t ->
       let e',h' = f e h in
       let e'',t' = list_fold_map f e' t in
         e'',h'::t'

(* (* tail-recursive version of the above function *)
let list_fold_map f e l = 
  let g (e,b') h = 
    let (e',h') = f e h in
      (e',h'::b') 
  in
  let (e',lrev) = List.fold_left g (e,[]) l in
    (e',List.rev lrev)
*)

(* The same, based on fold_right, with the effect accumulated on the right *)
let list_fold_map' f l e =
  List.fold_right (fun x (l,e) -> let (y,e) = f x e in (y::l,e)) l ([],e)

let list_map_assoc f = List.map (fun (x,a) -> (x,f a))

(* Arrays *)

let array_exists f v = 
  let rec exrec = function
    | -1 -> false
    | n -> (f v.(n)) || (exrec (n-1))
  in 
  exrec ((Array.length v)-1) 

let array_for_all f v = 
  let rec allrec = function
    | -1 -> true
    | n -> (f v.(n)) && (allrec (n-1))
  in 
  allrec ((Array.length v)-1) 

let array_for_all2 f v1 v2 =
  let rec allrec = function
    | -1 -> true
    | n -> (f v1.(n) v2.(n)) && (allrec (n-1))
  in 
  let lv1 = Array.length v1 in
  lv1 = Array.length v2 && allrec (pred lv1) 

let array_for_all3 f v1 v2 v3 =
  let rec allrec = function
    | -1 -> true
    | n -> (f v1.(n) v2.(n) v3.(n)) && (allrec (n-1))
  in 
  let lv1 = Array.length v1 in
  lv1 = Array.length v2 && lv1 = Array.length v3 && allrec (pred lv1) 

let array_for_all4 f v1 v2 v3 v4 =
  let rec allrec = function
    | -1 -> true
    | n -> (f v1.(n) v2.(n) v3.(n) v4.(n)) && (allrec (n-1))
  in 
  let lv1 = Array.length v1 in
  lv1 = Array.length v2 &&
  lv1 = Array.length v3 &&
  lv1 = Array.length v4 &&
    allrec (pred lv1) 

let array_hd v = 
  match Array.length v with
    | 0 -> failwith "array_hd"
    | _ -> v.(0)

let array_tl v = 
  match Array.length v with
    | 0 -> failwith "array_tl"
    | n -> Array.sub v 1 (pred n)

let array_last v =
  match Array.length v with
    | 0 -> failwith "array_last"
    | n -> v.(pred n)

let array_cons e v = Array.append [|e|] v

let array_fold_right_i f v a =
  let rec fold a n =
    if n=0 then a
    else
      let k = n-1 in
      fold (f k v.(k) a) k in
  fold a (Array.length v)

let array_fold_left_i f v a =
  let n = Array.length a in
  let rec fold i v = if i = n then v else fold (succ i) (f i v a.(i)) in
  fold 0 v

let array_fold_right2 f v1 v2 a =
  let lv1 = Array.length v1 in
  let rec fold a n =
    if n=0 then a
    else
      let k = n-1 in
      fold (f v1.(k) v2.(k) a) k in
  if Array.length v2 <> lv1 then invalid_arg "array_fold_right2";
  fold a lv1

let array_fold_left2 f a v1 v2 =
  let lv1 = Array.length v1 in
  let rec fold a n = 
    if n >= lv1 then a else fold (f a v1.(n) v2.(n)) (succ n)
  in
  if Array.length v2 <> lv1 then invalid_arg "array_fold_left2";
  fold a 0

let array_fold_left2_i f a v1 v2 =
  let lv1 = Array.length v1 in
  let rec fold a n = 
    if n >= lv1 then a else fold (f n a v1.(n) v2.(n)) (succ n)
  in
  if Array.length v2 <> lv1 then invalid_arg "array_fold_left2";
  fold a 0

let array_fold_left_from n f a v = 
  let rec fold a n =
    if n >= Array.length v then a else fold (f a v.(n)) (succ n)
  in 
  fold a n

let array_fold_right_from n f v a = 
  let rec fold n =
    if n >= Array.length v then a else f v.(n) (fold (succ n))
  in 
  fold n

let array_app_tl v l = 
  if Array.length v = 0 then invalid_arg "array_app_tl";
  array_fold_right_from 1 (fun e l -> e::l) v l

let array_list_of_tl v =
  if Array.length v = 0 then invalid_arg "array_list_of_tl";
  array_fold_right_from 1 (fun e l -> e::l) v []

let array_map_to_list f v =
  List.map f (Array.to_list v)

let array_chop n v =
  let vlen = Array.length v in
  if n > vlen then failwith "array_chop";
  (Array.sub v 0 n, Array.sub v n (vlen-n))

exception Local of int

(* If none of the elements is changed by f we return ar itself.
   The for loop looks for the first such an element.
   If found it is temporarily stored in a ref and the new array is produced, 
   but f is not re-applied to elements that are already checked *)
let array_smartmap f ar = 
  let ar_size = Array.length ar in
  let aux = ref None in
  try
    for i = 0 to ar_size-1 do
      let a = ar.(i) in
      let a' = f a in
	if a != a' then (* pointer (in)equality *) begin
	  aux := Some a';
	  raise (Local i)
	end
    done;
    ar
  with
      Local i -> 
	let copy j = 
	  if j<i then ar.(j) 
	  else if j=i then 
	    match !aux with Some a' -> a' | None -> failwith "Error"
	  else f (ar.(j))
	in
	  Array.init ar_size copy

let array_map2 f v1 v2 =
  if Array.length v1 <> Array.length v2 then invalid_arg "array_map2";
  if Array.length v1 == 0 then 
    [| |] 
  else begin
    let res = Array.create (Array.length v1) (f v1.(0) v2.(0)) in
    for i = 1 to pred (Array.length v1) do
      res.(i) <- f v1.(i) v2.(i)
    done;
    res
  end

let array_map2_i f v1 v2 =
  if Array.length v1 <> Array.length v2 then invalid_arg "array_map2";
  if Array.length v1 == 0 then 
    [| |] 
  else begin
    let res = Array.create (Array.length v1) (f 0 v1.(0) v2.(0)) in
    for i = 1 to pred (Array.length v1) do
      res.(i) <- f i v1.(i) v2.(i)
    done;
    res
  end

let array_map3 f v1 v2 v3 =
  if Array.length v1 <> Array.length v2 ||
     Array.length v1 <> Array.length v3 then invalid_arg "array_map3";
  if Array.length v1 == 0 then 
    [| |] 
  else begin
    let res = Array.create (Array.length v1) (f v1.(0) v2.(0) v3.(0)) in
    for i = 1 to pred (Array.length v1) do
      res.(i) <- f v1.(i) v2.(i) v3.(i)
    done;
    res
  end

let array_map_left f a = (* Ocaml does not guarantee Array.map is LR *)
  let l = Array.length a in (* (even if so), then we rewrite it *)
  if l = 0 then [||] else begin
    let r = Array.create l (f a.(0)) in
    for i = 1 to l - 1 do
      r.(i) <- f a.(i)
    done;
    r
  end

let array_map_left_pair f a g b =
  let l = Array.length a in
  if l = 0 then [||],[||] else begin
    let r = Array.create l (f a.(0)) in
    let s = Array.create l (g b.(0)) in
    for i = 1 to l - 1 do
      r.(i) <- f a.(i);
      s.(i) <- g b.(i)
    done;
    r, s
  end

let pure_functional = false

let array_fold_map' f v e =
if pure_functional then
  let (l,e) =
    Array.fold_right 
      (fun x (l,e) -> let (y,e) = f x e in (y::l,e))
      v ([],e) in
  (Array.of_list l,e)
else
  let e' = ref e in
  let v' = Array.map (fun x -> let (y,e) = f x !e' in e' := e; y) v in
  (v',!e')

(* Matrices *)

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

(* Functions *)

let identity x = x

let compose f g x = f (g x)

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

let repeat n f x =
  for i = 1 to n do f x done

let iterate_for a b f x =
  let rec iterate i v = if i > b then v else iterate (succ i) (f i v) in
  iterate a x
 
(* Misc *)

type ('a,'b) union = Inl of 'a | Inr of 'b

module Intset = Set.Make(struct type t = int let compare = compare end)

module Intmap = Map.Make(struct type t = int let compare = compare end)

let intmap_in_dom x m =
  try let _ = Intmap.find x m in true with Not_found -> false

let intmap_to_list m = Intmap.fold (fun n v l -> (n,v)::l) m []

let intmap_inv m b = Intmap.fold (fun n v l -> if v = b then n::l else l) m []

let interval n m = 
  let rec interval_n (l,m) =
    if n > m then l else interval_n (m::l,pred m)
  in 
  interval_n ([],m)

let in_some x = Some x

let out_some = function
  | Some x -> x
  | None -> failwith "out_some"

let option_app f = function
  | None -> None
  | Some x -> Some (f x)

let option_cons a l = match a with
  | Some x -> x::l
  | None -> l

let option_fold_left2 f e a b = match (a,b) with
  | Some x, Some y -> f e x y
  | _ -> e

let option_fold_right f a e = match a with
  | Some x -> f x e
  | _ -> e

let option_compare f a b = match (a,b) with
  | None, None -> true
  | Some a', Some b' -> f a' b'
  | _ -> failwith "option_compare"

let option_iter f = function
  | None -> ()
  | Some x -> f x

let option_smartmap f a = match a with
  | None -> a
  | Some x -> let x' = f x in if x'==x then a else Some x'

let map_succeed f = 
  let rec map_f = function 
    | [] -> []
    |  h::t -> try (let x = f h in x :: map_f t) with Failure _ -> map_f t
  in 
  map_f 

(* Pretty-printing *)
  
let pr_spc = spc
let pr_fnl = fnl
let pr_int = int
let pr_str = str
let pr_coma () = str "," ++ spc ()
let pr_semicolon () = str ";" ++ spc ()
let pr_bar () = str "|" ++ spc ()
let pr_arg pr x = spc () ++ pr x
let pr_opt pr = function None -> mt () | Some x -> pr_arg pr x

let pr_ord n =
  let suff = match n mod 10 with 1 -> "st" | 2 -> "nd" | _ -> "th" in
  int n ++ str suff

let rec prlist elem l = match l with 
  | []   -> mt ()
  | h::t -> Stream.lapp (fun () -> elem h) (prlist elem t)

let rec prlist_with_sep sep elem l = match l with
  | []   -> mt ()
  | [h]  -> elem h
  | h::t ->
      let e = elem h and s = sep() and r = prlist_with_sep sep elem t in
      e ++ s ++ r

let pr_vertical_list pr = function
  | [] -> str "none" ++ fnl ()
  | l -> fnl () ++ str "  " ++ hov 0 (prlist_with_sep pr_fnl pr l) ++ fnl ()
      
let prvecti elem v =
  let n = Array.length v in
  let rec pr i =
    if i = 0 then 
      elem 0 v.(0)
    else
      let r = pr (i-1) and e = elem i v.(i) in r ++ e
  in
  if n = 0 then mt () else pr (n - 1)

let prvect_with_sep sep elem v =
  let rec pr n =
    if n = 0 then 
      elem v.(0)
    else 
      let r = pr (n-1) and s = sep() and e = elem v.(n) in 
      r ++ s ++ e
      in
  let n = Array.length v in
  if n = 0 then mt () else pr (n - 1)

(*s Size of ocaml values. *)

module Size = struct
  
  open Obj

  (*s Pointers already visited are stored in a hash-table, where
      comparisons are done using physical equality. *)

  module H = Hashtbl.Make(
    struct 
      type t = Obj.t 
      let equal = (==) 
      let hash o = Hashtbl.hash (magic o : int)
    end)
	       
  let node_table = (H.create 257 : unit H.t)
		     
  let in_table o = try H.find node_table o; true with Not_found -> false
      
  let add_in_table o = H.add node_table o ()
			 
  let reset_table () = H.clear node_table
			 
  (*s Objects are traversed recursively, as soon as their tags are less than
      [no_scan_tag]. [count] records the numbers of words already visited. *)

  let size_of_double = size (repr 1.0)
			 
  let count = ref 0
		
  let rec traverse t =
    if not (in_table t) then begin
      add_in_table t;
      if is_block t then begin
	let n = size t in
	let tag = tag t in
	if tag < no_scan_tag then begin
	  count := !count + 1 + n;
	  for i = 0 to n - 1 do
      	    let f = field t i in 
	    if is_block f then traverse f
	  done
	end else if tag = string_tag then
	  count := !count + 1 + n 
	else if tag = double_tag then
	  count := !count + size_of_double
	else if tag = double_array_tag then
	  count := !count + 1 + size_of_double * n 
	else
	  incr count
      end
    end
      
  (*s Sizes of objects in words and in bytes. The size in bytes is computed
      system-independently according to [Sys.word_size]. *)

  let size_w o =
    reset_table ();
    count := 0;
    traverse (repr o);
    !count

  let size_b o = (size_w o) * (Sys.word_size / 8)

  let size_kb o = (size_w o) / (8192 / Sys.word_size)

end

let size_w = Size.size_w
let size_b = Size.size_b
let size_kb = Size.size_kb

(*s Total size of the allocated ocaml heap. *)

let heap_size () =
  let stat = Gc.stat ()
  and control = Gc.get () in
  let max_words_total = stat.Gc.heap_words + control.Gc.minor_heap_size in
  (max_words_total * Sys.word_size / 8)

let heap_size_kb () = (heap_size () + 1023) / 1024

(*s interruption *)

let interrupt = ref false
let check_for_interrupt () = 
  if !interrupt then begin interrupt := false; raise Sys.Break end