summaryrefslogtreecommitdiffstats
path: root/src/parser_helper.ml
blob: 43d60a402b6abd85545f67471f9dc2866a05951f (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
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
open Types
open Common
open Printf

let bpos = -1, -1

let raw_pos2pos(a, b) = !Info.current_file, a, b
let raw_pos_range { pos = (a1, b1) } { pos = (a2, b2) } = (if a1 = -1 then a2 else a1), (if b2 = -1 then b1 else b2)
let pos_range esp1 esp2 = raw_pos2pos (raw_pos_range esp1 esp2)
let get_pos pesp = raw_pos2pos pesp.pos
let get_pos_start { pos = (start, _) } = start
let get_pos_end { pos = (_, end_) } = end_
let var_dollar_ pos = Deref(I_scalar, Ident(None, "_", pos))
let var_STDOUT = Deref(I_star, Ident(None, "STDOUT", raw_pos2pos bpos))

let new_any mcontext any spaces pos = { mcontext = mcontext ; any = any ; spaces = spaces ; pos = pos }
let new_any_ any spaces pos = new_any M_unknown any spaces pos
let new_esp mcontext e esp_start esp_end = new_any mcontext e esp_start.spaces (raw_pos_range esp_start esp_end)
let new_1esp e esp = new_any esp.mcontext e esp.spaces esp.pos
let new_pesp mcontext prio e esp_start esp_end = new_any mcontext { priority = prio ; expr = e } esp_start.spaces (raw_pos_range esp_start esp_end)
let new_1pesp prio e esp = new_any esp.mcontext { priority = prio ; expr = e } esp.spaces esp.pos
let default_esp e = new_any M_unknown e Space_none bpos
let default_pesp prio e = new_any M_unknown { priority = prio ; expr = e } Space_none bpos

let split_name_or_fq_name full_ident =
  match split_at2 ':'':' full_ident with
  | [] -> internal_error "split_ident"
  | [ident] -> None, ident
  | l ->
      let fql, name = split_last l in
      let fq = String.concat "::" fql in
      Some fq, name

let is_var_dollar_ = function
  | Deref(I_scalar, Ident(None, "_", _)) -> true
  | _ -> false
let is_var_number_match = function
  | Deref(I_scalar, Ident(None, s, _)) -> String.length s = 1 && s.[0] <> '0' && char_is_number s.[0]
  | _ -> false

let non_scalar_context context = context = I_hash || context = I_array
let is_scalar_context context = context = I_scalar
  
let rec is_not_a_scalar = function
  | Deref_with(_, context, _, _)
  | Deref(context, _) -> non_scalar_context context
  | List []
  | List(_ :: _ :: _) -> true
  | Call(Deref(I_func, Ident(None, "map", _)), _)
  | Call(Deref(I_func, Ident(None, "grep", _)), _) -> true
  | Call_op("?:", [ _cond ; a; b ], _) -> is_not_a_scalar a || is_not_a_scalar b
  | _ -> false

let is_a_scalar = function
  | Ref _
  | Num _
  | Raw_string _
  | String _
  | Call(Deref(I_func, Ident(None, "N", _)), _) -> true
  | My_our(_, [ context, _ ], _)
  | Deref_with(_, context, _, _)
  | Deref(context, _) -> is_scalar_context context
  | _ -> false

let is_a_string = function
  | String _ | Raw_string _ -> true
  | _ -> false

let is_parenthesized = function
  | List[]
  | List[List _] -> true
  | _ -> false

let un_parenthesize = function
  | List[List[e]] -> e
  | List[e] -> e
  | _ -> internal_error "un_parenthesize"

let rec un_parenthesize_full = function
  | List[e] -> un_parenthesize_full e
  | e -> e

let rec un_parenthesize_full_l = function
  | [ List l ] -> un_parenthesize_full_l l
  | l -> l

let is_always_true = function
  | Num(n, _) -> float_of_string n <> 0.
  | Raw_string(s, _) -> s <> ""
  | String(l, _) -> l <> []
  | Ref _ -> true
  | _ -> false

let is_always_false = function
  | Num(n, _) -> float_of_string n = 0.
  | Raw_string(s, _) -> s = ""
  | String(l, _) -> l = []
  | List [] -> true
  | Ident(None, "undef", _) -> true
  | _ -> false

let rec is_lvalue = function
  | Call(Deref(I_func, Ident(None, f, _)), _) -> List.mem f [ "substr" ]

  | Call_op("?:", [ _ ; a ; b ], _) -> is_lvalue a && is_lvalue b

  | Call_op("local", l, _)
  | List [ List l ] 
    -> List.for_all is_lvalue l

  | My_our _
  | Deref(_, _)
  | Deref_with(_, _, _, _)
  | Ident(None, "undef", _)
    -> true

  | _ -> false

let not_complex e =
  if is_parenthesized e then true else
  let rec not_complex_ op = function
    | Call_op("?:", _, _) -> false
    | Call_op(op', l, _) -> op <> op' && List.for_all (not_complex_ op') l
    | e -> not (is_parenthesized e)
  in not_complex_ "" (un_parenthesize_full e)

let not_simple = function
  | Num _ | Ident _ | Deref(_, Ident _) -> false
  | _ -> true

let context2s = function
  | I_scalar -> "$"
  | I_hash -> "%"
  | I_array -> "@"
  | I_func -> "&"
  | I_raw -> ""
  | I_star -> "*"
let variable2s(context, ident) = context2s context ^ ident

let rec string_of_fromparser = function
  | Semi_colon -> ";"
  | Undef -> "undef"
  | Num(num, _) -> num

  | Raw_string(s, _) -> "\"" ^ s ^ "\""
  | String(l, _) -> 
      let l' = List.map (fun (s, e) -> 
	s ^ if e = List[] then "" else string_of_fromparser e
      ) l in
      "\"" ^ String.concat "" l' ^ "\""

  | Ident(None, s, _) -> s
  | Ident(Some fq, s, _) -> fq ^ "::" ^ s
  | My_our(myour, l, _) -> myour ^ "(" ^ String.concat "," (List.map (fun (context, s) -> context2s context ^ s) l) ^ ")"

  | Anonymous_sub(_, e, _) -> "sub { " ^ string_of_fromparser e ^ " }"
  | Ref(_, e) -> "\\" ^ string_of_fromparser e
  | Deref(context, e) -> context2s context ^ string_of_fromparser e

  | Diamond(None) -> "<>"
  | Diamond(Some e) -> "<" ^ string_of_fromparser e ^ ">"

  | Sub_declaration(name, _prototype, body, Real_sub_declaration) ->
      "sub " ^ string_of_fromparser name ^ " { " ^ string_of_fromparser body ^ " }"

  | Sub_declaration(name, _prototype, body, Glob_assign) ->
      "*" ^ string_of_fromparser name ^ " = sub { " ^ string_of_fromparser body ^ " };"

  | Deref_with(_, _, _e1, _e2) ->
      internal_error "todo"

  | Package(p) -> "package " ^ string_of_fromparser p

  | Use(e, []) -> "use " ^ string_of_fromparser e
  | Use(e, l) -> "use " ^ string_of_fromparser e ^ "(" ^ lstring_of_fromparser l

  | List l -> lstring_of_fromparser_parentheses l
  | Block l -> "{ " ^ lstring_of_fromparser l ^ " }"
  | Call_op(op, l, _) -> op ^ lstring_of_fromparser_parentheses l

  | Call(e, l) -> string_of_fromparser e ^ lstring_of_fromparser l

  | Method_call(obj, meth, l) -> 
      let para = if l = [] then "" else lstring_of_fromparser_parentheses l in
      string_of_fromparser obj ^ "->" ^ string_of_fromparser meth ^ para

  | Label(e) -> e ^ ": "

  | Perl_checker_comment _ -> ""
  | Too_complex -> "XXX"

and lstring_of_fromparser l = String.concat ", " (List.map string_of_fromparser l)
and lstring_of_fromparser_parentheses l = "(" ^ lstring_of_fromparser l ^ ")"

let rec is_same_fromparser a b =
  match a, b with
  | Undef, Undef -> true
  | Ident(fq1, s1, _), Ident(fq2, s2, _) -> fq1 = fq2 && s1 = s2
  | Num(s1, _), Num(s2, _) 
  | Raw_string(s1, _), Raw_string(s2, _) -> s1 = s2

  | String(l1, _), String(l2, _) ->
      for_all2_ (fun (s1, e1) (s2, e2) -> s1 = s2 && is_same_fromparser e1 e2) l1 l2

  | Ref(c1, e1), Ref(c2, e2)
  | Deref(c1, e1), Deref(c2, e2) -> c1 = c2 && is_same_fromparser e1 e2

  | Deref_with(c1, c_1, e1, e_1), Deref_with(c2, c_2, e2, e_2) -> c1 = c2 && c_1 = c_2 && is_same_fromparser e1 e2 && is_same_fromparser e_1 e_2

  | Diamond(None), Diamond(None) -> true
  | Diamond(Some e1), Diamond(Some e2) -> is_same_fromparser e1 e2

  | List(l1), List(l2) -> for_all2_ is_same_fromparser l1 l2

  | Call_op(op1, l1, _), Call_op(op2, l2, _) -> op1 = op2 && for_all2_ is_same_fromparser l1 l2
  | Call(e1, l1), Call(e2, l2) -> is_same_fromparser e1 e2 && for_all2_ is_same_fromparser l1 l2

  | Method_call(e1, m1, l1), Method_call(e2, m2, l2) ->
      is_same_fromparser e1 e2 && is_same_fromparser m1 m2 && for_all2_ is_same_fromparser l1 l2

  | _ -> false

let from_scalar esp =
  match esp.any with
  | Deref(I_scalar, ident) -> ident
  | _ -> internal_error "from_scalar"

let from_array esp =
  match esp.any with
  | Deref(I_array, ident) -> ident
  | _ -> internal_error "from_array"

let rec get_pos_from_expr = function
  | Anonymous_sub(_, _, pos)
  | String(_, pos)
  | Call_op(_, _, pos)
  | Perl_checker_comment(_, pos)
  | My_our(_, _, pos)
  | Raw_string(_, pos)
  | Num(_, pos)
  | Ident(_, _, pos)
      -> pos

  | Package e
  | Ref(_, e)
  | Deref(_, e)
  | Sub_declaration(e, _, _, _)
  | Deref_with(_, _, e, _)
  | Use(e, _)
  | Call(e, _)
  | Method_call(_, e, _)
      -> get_pos_from_expr e

  | Diamond(option_e) 
      -> if option_e = None then raw_pos2pos bpos else get_pos_from_expr (some option_e)
      
  | List l
  | Block l
      -> if l = [] then raw_pos2pos bpos else get_pos_from_expr (List.hd l)

  | Semi_colon
  | Too_complex
  | Undef
  | Label _
      -> raw_pos2pos bpos

let msg_with_rawpos (start, end_) msg = Info.pos2sfull_current start end_ ^ msg
let die_with_rawpos raw_pos msg = failwith (msg_with_rawpos raw_pos msg)
let warn warn_types raw_pos msg = if Flags.are_warning_types_set warn_types then print_endline_flush (msg_with_rawpos raw_pos msg)

let die_rule msg = die_with_rawpos (Parsing.symbol_start(), Parsing.symbol_end()) msg
let warn_rule warn_types msg = warn warn_types (Parsing.symbol_start(), Parsing.symbol_end()) msg

let warn_verb warn_types pos msg = if not !Flags.quiet then warn warn_types (pos, pos) msg
let warn_too_many_space start = warn_verb [Warn_white_space] start "you should have only one space here"
let warn_no_space	start = warn_verb [Warn_white_space] start "you should have a space here"
let warn_cr		start = warn_verb [Warn_white_space] start "you should not have a carriage-return (\\n) here"
let warn_space		start = warn_verb [Warn_white_space] start "you should not have a space here"

let rec prio_less = function
  | P_none, _ | _, P_none -> internal_error "prio_less"

  | P_paren_wanted prio1, prio2
  | prio1, P_paren_wanted prio2 -> prio_less(prio1, prio2)

  | P_ternary, P_or -> false
  | P_ternary, P_and -> false

  | _, P_loose -> true
  | P_loose, _ -> false
  | _, P_or -> true
  | P_or, _ -> false

  | _, P_and -> true
  | P_and, _ -> false
  | _, P_call_no_paren -> true
  | P_call_no_paren, _ -> false
  | _, P_comma -> true
  | P_comma, _ -> false
  | _, P_assign -> true
  | P_assign, _ -> false
  | _, P_ternary -> true
  | P_ternary, _ -> false

  | _, P_tight_or -> true
  | P_tight_or, _ -> false
  | _, P_tight_and -> true
  | P_tight_and, _ -> false

  | P_bit, P_bit -> true
  | P_bit, _ -> false

  | _, P_expr -> true
  | P_expr, _ -> false

  | _, P_eq -> true
  | P_eq, _ -> false
  | _, P_cmp -> true
  | P_cmp, _ -> false
  | _, P_uniop -> true
  | P_uniop, _ -> false
  | _, P_add -> true
  | P_add, _ -> false
  | _, P_mul -> true
  | P_mul, _ -> false
  | _, P_tight -> true
  | P_tight, _ -> false

  | _, P_paren _ -> true
  | P_paren _, _ -> true
  | P_tok, _ -> true

let prio_lo_check pri_out pri_in pos expr =
  if prio_less(pri_in, pri_out) then
    (match pri_in with
    | P_paren (P_paren_wanted _) -> ()
    | P_paren pri_in' ->
	if pri_in' <> pri_out && 
	   prio_less(pri_in', pri_out) && not_complex (un_parenthesize expr) then 
	  warn [Warn_suggest_simpler] pos "unneeded parentheses"
    | _ -> ())
  else
    (match expr with
    | Call(Deref(I_func, Ident(None, f, _)), _) when f <> "delete" && pri_in = P_uniop && pri_out = P_add 
      -> () (* ugly special case since we don't parse uniop correctly (eg: -d $_ . "foo" *)	
    | Call_op ("print", [Deref (I_star, Ident (None, "STDOUT", _)); (Deref(I_scalar, _) as ident)], _) -> 
	 warn [Warn_traps] pos (sprintf "use parentheses: replace \"print %s ...\" with \"print(%s ...)\"" (string_of_fromparser ident) (string_of_fromparser ident))
    | _ -> warn [Warn_traps] pos "missing parentheses (needed for clarity)")

let prio_lo pri_out in_ = prio_lo_check pri_out in_.any.priority in_.pos in_.any.expr ; in_.any.expr

let prio_lo_after pri_out in_ =
  if in_.any.priority = P_call_no_paren then in_.any.expr else prio_lo pri_out in_

let prio_lo_concat esp = prio_lo P_mul { esp with any = { esp.any with priority = P_paren_wanted esp.any.priority } }

let hash_ref esp = Ref(I_hash, prio_lo P_loose esp)

let sp_0 esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0 -> ()
  | Space_1
  | Space_n -> warn_space (get_pos_start esp)
  | Space_cr -> warn_cr (get_pos_start esp)

let sp_0_or_cr esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0 -> ()
  | Space_1
  | Space_n -> warn_space (get_pos_start esp)
  | Space_cr -> ()

let sp_1 esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0 -> warn_no_space (get_pos_start esp)
  | Space_1 -> ()
  | Space_n -> warn_too_many_space (get_pos_start esp)
  | Space_cr -> warn_cr (get_pos_start esp)

let sp_n esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0 -> warn_no_space (get_pos_start esp)
  | Space_1 -> ()
  | Space_n -> ()
  | Space_cr -> warn_cr (get_pos_start esp)

let sp_p esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0 -> warn_no_space (get_pos_start esp)
  | Space_1 -> ()
  | Space_n -> ()
  | Space_cr -> ()

let sp_cr esp =
  match esp.spaces with
  | Space_none -> ()
  | Space_0
  | Space_1
  | Space_n -> warn_verb [Warn_white_space] (get_pos_start esp) "you should have a carriage-return (\\n) here"
  | Space_cr -> ()

let sp_same esp1 esp2 =
  if esp1.spaces <> Space_0 then sp_p esp2
  else if esp2.spaces <> Space_0 then sp_p esp1

let function_to_context word_alone = function
  | "map" | "grep" | "grep_index" | "map_index" | "uniq" | "uniq_" -> M_array
  | "partition" -> M_tuple [ M_ref M_array ; M_ref M_array ]
  | "find" -> M_unknown_scalar
  | "any" | "every" -> M_bool
  | "find_index" -> M_int
  | "each_index" -> M_none
  | "N" | "N_" -> M_string

  | "chop" | "chomp" | "push" | "unshift" -> M_none	
  | "hex" | "length" | "time" | "fork" | "getppid" -> M_int
  | "eof" | "wantarray" -> M_int
  | "stat" | "lstat" -> M_list
  | "arch" | "quotemeta" | "join" | "lc" | "lcfirst" | "uc" | "ucfirst" -> M_string
	    
  | "split" -> M_array
  | "shift" | "pop" -> M_unknown_scalar
  | "die" | "return" | "redo" | "next" | "last" -> M_unknown
  | "caller" -> M_mixed [M_string ; M_list]
	
  | "ref" -> M_ref M_unknown_scalar
  | "undef" -> if word_alone then M_undef else M_none
  | _ -> M_unknown

let word_alone esp =
  let word = esp.any in
  let mcontext, e = match word with
  | Ident(None, f, pos) ->
      let e = match f with
      | "length" | "stat" | "lstat" | "chop" | "chomp" | "quotemeta" | "lc" | "lcfirst" | "uc" | "ucfirst" ->
	  Call(Deref(I_func, word), [var_dollar_ pos])
	    
      | "split" -> Call(Deref(I_func, word), [ Raw_string(" ", pos) ; var_dollar_ pos ])
      | "die"   -> Call(Deref(I_func, word), [ Deref(I_scalar, Ident(None, "@", raw_pos2pos bpos)) ])
      | "return" | "eof" | "caller" 
      | "redo" | "next" | "last" -> 
	  Deref(I_func, word)
	    
      | "hex" | "ref" -> 
	  warn_rule [Warn_complex_expressions] (sprintf "please use \"%s $_\" instead of \"%s\"" f f) ;
	  Call(Deref(I_func, word), [ Raw_string(" ", pos) ; var_dollar_ pos ])
      | "time" | "wantarray" | "fork" | "getppid" | "arch" -> 
	  warn_rule [Warn_complex_expressions] (sprintf "please use %s() instead of %s" f f) ;
	  Deref(I_func, word)
      | _ -> word
      in
      function_to_context true f, e
  | _ -> M_unknown, word
  in
  new_pesp mcontext P_tok e esp esp

let check_parenthesized_first_argexpr word esp =
  let want_space = word.[0] = '-' in
  if word = "return" then () else
  match esp.any.expr with
  | [ Call_op(_, (e' :: l), _) ]
  | e' :: l ->
      if is_parenthesized e' then
	if l = [] then 
	  (if want_space then sp_n else sp_0) esp
	else 
	  (* eg: join (" ", @l) . "\n" *)
	  die_with_rawpos (get_pos_start esp, get_pos_start esp) "please remove the space before the function call"
      else
	sp_p esp
  | _ -> 
      if word = "time" then die_rule "please use time() instead of time";
      sp_p esp

let check_parenthesized_first_argexpr_with_Ident ident esp =
  if esp.any.priority = P_tok then ();
  (match ident with
  | Ident(Some _, _, _) ->
      (match esp.any.expr with
      | [e] when is_parenthesized e -> ()
      | _ -> warn_rule [Warn_suggest_simpler] "use parentheses around argument (otherwise it might cause syntax errors if the package is \"require\"d and not \"use\"d")
  | Ident(None, word, _) when List.mem word ["ref" ; "readlink"] ->
      if esp.any.priority <> P_tok then warn_rule [Warn_complex_expressions] "use parentheses around argument"
  | _ -> ());
  check_parenthesized_first_argexpr (string_of_fromparser ident) esp

let check_hash_subscript esp =
  let can_be_raw_string = function
    | "" | "x" | "y" -> false (* special case for {'y'} otherwise the emacs mode goes wild, special case for {'x'} to have the same as {'y'} (since they usually go together) *)
    | s -> 
	char_is_alpha s.[0] && (String.length s = 1 || string_forall_with char_is_alphanumerical_ 1 s)
  in
  match esp.any.expr with
  | List [String ([(s, List [])], _)] when can_be_raw_string s -> warn [Warn_suggest_simpler] esp.pos (sprintf "{\"%s\"} can be written {%s}" s s)
  | List [Raw_string(s, _)] when can_be_raw_string s -> warn [Warn_suggest_simpler] esp.pos (sprintf "{'%s'} can be written {%s}" s s)
  | _ -> ()

let check_arrow_needed arrow = function
  | Deref_with(I_array, I_scalar, List [List [Call _]], _) -> () (* "->" needed for (f())[0]->{XX} *)
  | Deref_with _ -> warn [Warn_suggest_simpler] arrow.pos "the arrow \"->\" is unneeded"
  | _ -> ()

let check_scalar_subscripted esp =
  match esp.any with
  | Deref(I_scalar, Deref _) -> warn_rule [Warn_complex_expressions] "for complex dereferencing, use \"->\""
  | _ -> ()

let negatable_ops = collect (fun (a, b) -> [ a, b ; b, a ]) [
  "==", "!=" ; 
  "eq", "ne" ;
]

let check_negatable_expr esp =
  match un_parenthesize_full esp.any.expr with
  | Call_op("m//", var :: _, _) when not (is_var_dollar_ var) ->
      warn_rule [Warn_suggest_simpler] "!($var =~ /.../) is better written $var !~ /.../"
  | Call_op("!m//", var :: _, _) when not (is_var_dollar_ var) ->
      warn_rule [Warn_suggest_simpler] "!($var !~ /.../) is better written $var =~ /.../"
  | Call_op(op, _, _) ->
      (try
	let neg_op = List.assoc op negatable_ops in
        warn_rule [Warn_suggest_simpler] (Printf.sprintf "!($foo %s $bar) is better written $foo %s $bar" op neg_op)
      with Not_found -> ())
  | _ -> ()

let check_ternary_paras(cond, a, b) =
  let rec dont_need_short_circuit_rec = function
    | Num _
    | Raw_string _
    | String ([(_, List [])], _) 
      -> true
    | Call(Deref(I_func, Ident(None, "N", _)), [ List(String _ :: l) ])
    | Call_op(".", l, _)
    | Ref(I_hash, List l)
    | List l -> List.for_all dont_need_short_circuit_rec l
    | _ -> false
  in
  let rec dont_need_short_circuit = function
    | Ref(_, Deref(_, Ident _))
    | Deref(_, Ident _) -> true
    | Ref(I_hash, List l)
    | List l -> List.for_all dont_need_short_circuit l
    | e -> dont_need_short_circuit_rec e
  in
  let check_ternary_para = function
    | List [] -> warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you may use if_() here\n  beware that the short-circuit semantic of ?: is not kept\n  if you want to keep the short-circuit behaviour, replace () with @{[]} and there will be no warning anymore"
    | _ -> ()
  in
  if dont_need_short_circuit a || is_same_fromparser cond a then check_ternary_para b;
  if dont_need_short_circuit b || is_same_fromparser cond b then check_ternary_para a;
  if is_same_fromparser cond a && is_a_scalar a && is_a_scalar b then warn_rule [Warn_suggest_simpler] "you can replace \"$foo ? $foo : $bar\" with \"$foo || $bar\"";
  [ cond; a; b ]

let check_unneeded_var_dollar_ esp =
  if is_var_dollar_ esp.any.expr then warn [Warn_suggest_simpler] esp.pos "\"$_ =~ /regexp/\" can be written \"/regexp/\"" else
  if is_var_number_match esp.any.expr then warn [Warn_complex_expressions] esp.pos "do not use the result of a match (eg: $1) to match another pattern"
let check_unneeded_var_dollar_not esp =
  if is_var_dollar_ esp.any.expr then warn [Warn_suggest_simpler] esp.pos "\"$_ !~ /regexp/\" can be written \"!/regexp/\"" else
  if is_var_number_match esp.any.expr then warn [Warn_complex_expressions] esp.pos "do not use the result of a match (eg: $1) to match another pattern"
let check_unneeded_var_dollar_s esp = 
  let expr = esp.any.expr in
  if is_var_dollar_ expr then warn [Warn_suggest_simpler] esp.pos "\"$_ =~ s/regexp/.../\" can be written \"s/regexp/.../\"" else
  if is_var_number_match expr then warn [Warn_traps] esp.pos "do not modify the result of a match (eg: $1)" else
  let expr = match expr with
  | List [List [Call_op("=", [ expr; _], _)]] -> expr (* check $xx in ($xx = ...) =~ ... *)
  | _ -> expr in
  if is_a_string expr || not (is_a_scalar expr) then warn [Warn_complex_expressions] esp.pos "you can only use s/// on a variable"

let check_my esp = if esp.any <> "my" then die_rule "syntax error"
let check_foreach esp = if esp.any = "for"     then warn [Warn_normalized_expressions] esp.pos "write \"foreach\" instead of \"for\""
let check_for     esp = if esp.any = "foreach" then warn [Warn_normalized_expressions] esp.pos "write \"for\" instead of \"foreach\""
let check_for_foreach esp arg =
  match arg.any.expr with
  | List [ Deref(I_scalar, _) ] ->
      if esp.any = "foreach" then warn [Warn_normalized_expressions] esp.pos "you are using the special trick to locally set $_ with a value, for this please use \"for\" instead of \"foreach\""
  | List [ Deref_with(context, I_scalar, _, _) ] when context <> I_func -> 
      if esp.any = "foreach" then warn [Warn_normalized_expressions] esp.pos "you are using the special trick to locally set $_ with a value, for this please use \"for\" instead of \"foreach\""
  | List [ Deref(I_hash, _) ] ->
      warn [Warn_traps] esp.pos "foreach with a hash is usually an error"
  | _ -> 
      if esp.any = "for" then warn [Warn_normalized_expressions] esp.pos "write \"foreach\" instead of \"for\""

let check_block_expr has_semi_colon last_expr esp_last esp_BRACKET_END =
  sp_p esp_BRACKET_END ;

  if esp_BRACKET_END.spaces = Space_cr then
    (if not has_semi_colon then warn_verb [Warn_white_space] (get_pos_end esp_last) "missing \";\"")
  else
    (if last_expr = Semi_colon then warn_verb [Warn_white_space] (get_pos_end esp_last) "spurious \";\" before closing block")

let check_block_lines esp_lines esp_BRACKET_END =
  match fst esp_lines.any with
  | [] -> 
      sp_0_or_cr esp_BRACKET_END
  | l ->
      (if List.hd l = Semi_colon then sp_0 else sp_p) esp_lines ;
      check_block_expr (snd esp_lines.any) (last l) esp_lines esp_BRACKET_END

let check_unless_else elsif else_ =
  if elsif.any <> [] then warn [Warn_complex_expressions] elsif.pos "don't use \"elsif\" with \"unless\" (replace \"unless\" with \"if\")";
  if else_.any <> [] then warn [Warn_complex_expressions] else_.pos "don't use \"else\" with \"unless\" (replace \"unless\" with \"if\")"

let check_my_our_paren { any = ((comma_closed, _), l) } after_esp = 
  (if l = [] then sp_0 else sp_1) after_esp ; 
  if not comma_closed then die_rule "syntax error"

let check_simple_pattern = function
  | [ String([ st, List [] ], _); Raw_string("", _) ] ->
      if String.length st > 2 &&
	st.[0] = '^' && st.[String.length st - 1] = '$' then
	let st = skip_n_char_ 1 1 st in
	if string_forall_with char_is_alphanumerical_ 0 st then
	  warn_rule [Warn_suggest_simpler] (sprintf "\"... =~ /^%s$/\" is better written \"... eq '%s'\"" st st)
  | _ -> ()

let rec only_one esp =
  match esp.any with
  | [List l'] -> only_one { esp with any = l' }
  | [e] -> e
  | [] -> die_with_rawpos esp.pos "you must give one argument"
  | _  -> die_with_rawpos esp.pos "you must give only one argument"

let only_one_array_ref esp =
  let e = only_one esp in
  (match e with
  | Call_op("last_array_index", [Deref(I_array, e)], _) ->
      warn [Warn_suggest_simpler] esp.pos (sprintf "you can replace $#%s with -1" (string_of_fromparser e))
  | _ -> ());
  e

let only_one_in_List esp =
  match esp.any.expr with
  | List l -> only_one { esp with any = l }
  | e -> e
  
let rec is_only_one_in_List = function
  | [List l] -> is_only_one_in_List l
  | [_] -> true
  | _ -> false

let maybe_to_Raw_string = function
  | Ident(None, s, pos) -> Raw_string(s, pos)
  | Ident(Some fq, s, pos) -> Raw_string(fq ^ "::" ^ s, pos)
  | e -> e

let to_List = function
  | [e] -> e
  | l -> List l

let deref_arraylen e = Call_op("last_array_index", [Deref(I_array, e)], raw_pos2pos bpos)
let deref_raw context e = 
  let e = match e with
  | Raw_string(s, pos) -> 
      let fq, ident = split_name_or_fq_name s in
      Ident(fq, ident, pos)
  | Deref(I_scalar, (Ident _ as ident)) ->
      warn_rule [Warn_suggest_simpler] (sprintf "%s{$%s} can be written %s$%s" (context2s context) (string_of_fromparser ident) (context2s context) (string_of_fromparser ident));
      e
  | _ -> e
  in Deref(context, e)

let to_Ident { any = (fq, name); pos = pos } = Ident(fq, name, raw_pos2pos pos)
let to_Raw_string { any = s; pos = pos } = Raw_string(s, raw_pos2pos pos)
let to_Method_call (object_, method_, para) = 
  match method_ with
  | Ident(Some "SUPER", name, pos) -> Method_call(maybe_to_Raw_string object_, Raw_string(name, pos), para)
  | Ident(Some _, _, _) -> Call(Deref(I_func, method_), maybe_to_Raw_string object_ :: para)
  | _ -> Method_call(maybe_to_Raw_string object_, maybe_to_Raw_string method_, para)
let to_Deref_with(from_context, to_context, ref_, para) =
  if is_not_a_scalar ref_ then warn_rule [] "bad deref";
  Deref_with(from_context, to_context, ref_, para)

let to_Deref_with_arrow arrow (from_context, to_context, ref_, para) =
  if from_context != I_func then check_arrow_needed arrow ref_ ;
  to_Deref_with(from_context, to_context, ref_, para)

let lines_to_Block esp_lines esp_BRACKET_END =
  check_block_lines esp_lines esp_BRACKET_END;
  Block (fst esp_lines.any)
  
let to_Local esp =
  let l = 
    match esp.any.expr with
    | List[List l] -> l
    | e -> [e]
  in
  let local_vars, local_exprs = fpartition (function
    | Deref(I_star as context, Ident(None, ident, _))
    | Deref(I_scalar as context, Ident(None, ("_" as ident), _)) ->
	Some(context, ident)
    | Deref(I_scalar, Ident _)
    | Deref(I_array, Ident _)
    | Deref(I_star, Ident _)
    | Deref_with(I_hash, I_scalar, Ident _, _)
    | Deref_with(I_hash, I_scalar, Deref(I_scalar, _), _)
    | Deref_with(I_hash, I_scalar, Deref_with(I_hash, I_scalar, Ident _, _), _)
    | Deref_with(I_hash, I_scalar, Deref_with(I_hash, I_scalar, Deref(I_scalar, Ident _), _), _) ->
	None
    | _ -> die_with_rawpos esp.pos "bad argument to \"local\""
  ) l in
  if local_vars = [] then Call_op("local", local_exprs, raw_pos2pos esp.pos)
  else if local_exprs = [] then My_our("local", local_vars, raw_pos2pos esp.pos)
  else die_with_rawpos esp.pos "bad argument to \"local\""

let sub_declaration (name, proto) body sub_kind = Sub_declaration(name, proto, Block body, sub_kind)
let anonymous_sub proto lines bracket_end = Anonymous_sub (proto, lines_to_Block lines bracket_end, raw_pos2pos lines.pos)
let call_with_same_para_special f = Call(f, [Deref(I_star, (Ident(None, "_", raw_pos2pos bpos)))])
let remove_call_with_same_para_special = function
  | Call(f, [Deref(I_star, (Ident(None, "_", _)))]) -> f
  | e -> e

let check_My_under_condition msg = function
  | List [ My_our("my", _, _) ] ->
      warn_rule [Warn_traps] "this is stupid"
  | List [ Call_op("=", [ My_our("my", _, _); _ ], _) ] ->
      warn_rule [Warn_traps] msg
  | _ -> ()

let cook_call_op op para pos =
  (match op with
  | "le" | "ge" | "eq" | "ne" | "gt" | "lt" | "cmp" ->
      if List.exists (function Num _ -> true | _ -> false) para then
	warn_rule [Warn_traps] (sprintf "you should use a number operator, not the string operator \"%s\" (or replace the number with a string)" op)
  | "." ->
      if List.exists (function Call(Deref(I_func, Ident(None, "N_", _)), _) -> true | _ -> false) para then
	warn_rule [Warn_MDK_Common; Warn_traps] "N_(\"xxx\") . \"yyy\" is dumb since the string \"xxx\" will never get translated"
  | _ -> ());

  (match op, para with
  | "if", List [Call_op ("=", [ _; e ], _)] :: _ when is_always_true e || is_always_false e -> 
      warn_rule [Warn_traps] "are you sure you did not mean \"==\" instead of \"=\"?"

  | "foreach", [ _; Block [ expr ; Semi_colon ] ]
  | "foreach", [ _; Block [ expr ] ] -> 
      (match expr with
      | Call_op("if infix", [ List [ Call(Deref(I_func, Ident(None, "push", _)), [ Deref(I_array, Ident _) as l ; Deref(I_scalar, Ident(None, "_", _)) ]) ] ; _ ], _) ->
	  let l = string_of_fromparser l in
	  warn_rule [Warn_suggest_functional] (sprintf "use \"push %s, grep { ... } ...\" instead of \"foreach (...) { push %s, $_ if ... }\"\n  or sometimes \"%s = grep { ... } ...\"" l l l)
      | Call_op("if infix", [ List [ Call(Deref(I_func, Ident(None, "push", _)), [ Deref(I_array, Ident _) as l; _ ]) ] ; _ ], _) ->
	  let l = string_of_fromparser l in
	  warn_rule [Warn_suggest_functional] (sprintf "use \"push %s, map { ... ? ... : () } ...\" instead of \"foreach (...) { push %s, ... if ... }\"\n  or sometimes \"%s = map { ... ? ... : () } ...\"\n  or sometimes \"%s = map { if_(..., ...) } ...\"" l l l l)

      | Call_op ("if", [ _; Block [ List [ Call_op("=", [Deref(I_scalar, _) as ret; Deref(I_scalar, Ident(None, "_", _)) ], _) ];
				    Semi_colon;
				    List [ Deref(I_func, Ident(None, "last", _)) ];
				    Semi_colon ] ], _) ->
	  warn_rule [Warn_suggest_functional; Warn_MDK_Common] (sprintf "use \"%s = find { ... } ...\"" (string_of_fromparser ret))

      | List [ Call(Deref(I_func, Ident(None, "push", _)), [ Deref(I_array, Ident _) as l; _ ]) ] ->
	  let l = string_of_fromparser l in
	  warn_rule [Warn_suggest_functional] (sprintf "use \"push %s, map { ... } ...\" instead of \"foreach (...) { push %s, ... }\"\n  or sometimes \"%s = map { ... } ...\"" l l l)
      | _ -> ())

  | "=", [My_our _; Ident(None, "undef", _)] -> 
      warn [Warn_suggest_simpler] pos "no need to initialize variable, it's done by default"
  | "=", [My_our _; List[]] -> 
      if Info.is_on_same_line_current pos then warn [Warn_suggest_simpler] pos "no need to initialize variables, it's done by default"

  | "=", [ Deref_with(I_array, I_scalar, id, Deref(I_array, id_)); _ ] when is_same_fromparser id id_ ->
      warn_rule [Warn_suggest_simpler] "\"$a[@a] = ...\" is better written \"push @a, ...\""

  | "=", [ Deref(I_star, String ([(sf1, List [])], _)); _ ] ->
      warn_rule [Warn_help_perl_checker] (sprintf "write *{'%s'} instead of *{\"%s\"}" sf1 sf1)

  | "||=", List [ List _ ] :: _
  | "&&=", List [ List _ ] :: _ -> warn_rule [Warn_complex_expressions] "remove the parentheses"
  | "||=", e :: _
  | "&&=", e :: _ -> if is_not_a_scalar e then warn_rule [Warn_traps] (sprintf "\"%s\" is only useful with a scalar" op)

  | "==", [Call_op("last_array_index", _, _); Num(n, _)] ->
      warn_rule [Warn_suggest_simpler] (sprintf "$#x == %s is better written @x == %d" n (1 + int_of_string n))
  | "==", [Call_op("last_array_index", _, _); Call_op("- unary", [Num (n, _)], _)] ->
      warn_rule [Warn_suggest_simpler] (sprintf "$#x == -%s is better written @x == %d" n (1 - int_of_string n))


  | "||", e :: _ when is_always_true  e -> warn_rule [Warn_strange] "<constant> || ... is the same as <constant>"
  | "&&", e :: _ when is_always_false e -> warn_rule [Warn_strange] "<constant> && ... is the same as <constant>"
  | "||", e :: _ when is_always_false e -> warn_rule [Warn_strange] "<constant> || ... is the same as ..."
  | "&&", e :: _ when is_always_true  e -> warn_rule [Warn_strange] "<constant> && ... is the same as ..."

  | "or",  e :: _ when is_always_true  (un_parenthesize_full e) -> warn_rule [Warn_strange] "<constant> or ... is the same as <constant>"
  | "and", e :: _ when is_always_false (un_parenthesize_full e) -> warn_rule [Warn_strange] "<constant> and ... is the same as <constant>"
  | "or",  e :: _ when is_always_false (un_parenthesize_full e) -> warn_rule [Warn_strange] "<constant> or ... is the same as ..."
  | "and", e :: _ when is_always_true  (un_parenthesize_full e) -> warn_rule [Warn_strange] "<constant> and ... is the same as ..."

  | "or", [ List [ Deref(I_scalar, id) ]; List [ Call_op("=", [ Deref(I_scalar, id_); _], _) ] ] when is_same_fromparser id id_ ->
      warn_rule [Warn_suggest_simpler] "\"$foo or $foo = ...\" can be written \"$foo ||= ...\""

  | "and", [ _cond ; expr ] -> check_My_under_condition "replace \"<cond> and my $foo = ...\" with \"my $foo = <cond> && ...\"" expr
  | "or",  [ _cond ; expr ] -> check_My_under_condition "replace \"<cond> or my $foo = ...\" with \"my $foo = !<cond> && ...\"" expr
      
  | _ -> ());

  match op, para with
  | "=", [ Deref(I_star, (Ident _ as f1)); Deref(I_star, (Ident _ as f2)) ] ->
      let s1, s2 = string_of_fromparser f1, string_of_fromparser f2 in
      warn [Warn_complex_expressions] pos (sprintf "\"*%s = *%s\" is better written \"*%s = \\&%s\"" s1 s2 s1 s2) ;
      sub_declaration (f1, None) [ call_with_same_para_special(Deref(I_func, f2)) ] Glob_assign
  | "=", [ Deref(I_star, Raw_string(sf1, pos_f1)); Deref(I_star, (Ident _ as f2)) ] ->
      let s2 = string_of_fromparser f2 in
      warn [Warn_help_perl_checker] pos (sprintf "\"*{'%s'} = *%s\" is better written \"*{'%s'} = \\&%s\"" sf1 s2 sf1 s2) ;
      sub_declaration (Ident(None, sf1, pos_f1), None) [ call_with_same_para_special(Deref(I_func, f2)) ] Glob_assign

  | "=", [ Deref(I_star, (Ident _ as f1)); Ref(I_scalar, Deref(I_func, (Ident _ as f2))) ] ->
      sub_declaration (f1, None) [ call_with_same_para_special(Deref(I_func, f2)) ] Glob_assign
  | "=", [ Deref(I_star, Raw_string(sf1, pos_f1)); Ref(I_scalar, Deref(I_func, (Ident _ as f2))) ] ->
      sub_declaration (Ident(None, sf1, pos_f1), None) [ call_with_same_para_special(Deref(I_func, f2)) ] Glob_assign

  | "=", [ Deref(I_star, (Ident _ as f1)); (Anonymous_sub(proto, sub, _)) ] ->
      sub_declaration (f1, proto) [ sub ] Glob_assign

  | _ -> Call_op(op, para, raw_pos2pos pos)

let to_Call_op mcontext op para esp_start esp_end = 
  let pos = raw_pos_range esp_start esp_end in
  new_any mcontext (cook_call_op op para pos) esp_start.spaces pos
let to_Call_op_ mcontext prio op para esp_start esp_end = 
  let pos = raw_pos_range esp_start esp_end in
  new_any mcontext { priority = prio ; expr = cook_call_op op para pos } esp_start.spaces pos
let to_Call_assign_op_ mcontext prio op left right esp_left esp_end = 
  if not (is_lvalue left) then warn [Warn_strange] esp_left.pos "invalid lvalue";
  to_Call_op_ mcontext prio op [ left ; right ] esp_left esp_end

let followed_by_comma expr true_comma =
  if true_comma then expr else
    match split_last expr with
    | l, Ident(None, s, pos) -> l @ [Raw_string(s, pos)]
    | _ -> expr


let pot_strings = Hashtbl.create 16
let po_comments = ref []
let po_comment esp = lpush po_comments esp.any

let check_format_a_la_printf s pos =
  let rec check_format_a_la_printf_ contexts i =
    try
      let i' = String.index_from s i '%' in
      try
	let contexts = 
	  match s.[i' + 1] with
	  | '%' -> contexts
	  | 'd' -> M_int :: contexts
	  | 's' | 'c' -> M_string :: contexts
	  | c -> warn [Warn_strange] (pos + i', pos + i') (sprintf "invalid command %%%c" c); contexts
	in
	check_format_a_la_printf_ contexts (i' + 2)
      with Invalid_argument _ -> warn [Warn_strange] (pos + i', pos + i') "invalid command %" ; contexts
    with Not_found -> contexts
  in check_format_a_la_printf_ [] 0
  
let generate_pot file = 
  let fd = open_out file in
  output_string fd 
("# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR Free Software Foundation, Inc.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#, fuzzy
msgid \"\"
msgstr \"\"
\"Project-Id-Version: PACKAGE VERSION\\n\"
\"POT-Creation-Date: " ^ input_line (Unix.open_process_in "date '+%Y-%m-%d %H:%M%z'") ^ "\\n\"
\"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\\n\"
\"Last-Translator: FULL NAME <EMAIL@ADDRESS>\\n\"
\"Language-Team: LANGUAGE <LL@li.org>\\n\"
\"MIME-Version: 1.0\\n\"
\"Content-Type: text/plain; charset=CHARSET\\n\"
\"Content-Transfer-Encoding: 8-bit\\n\"

") ;

  let rec print_formatted_char = function
    | '"'  -> output_char fd '\\'; output_char fd '"'
    | '\t' -> output_char fd '\\'; output_char fd 't'
    | '\\' -> output_char fd '\\'; output_char fd '\\'
    | '\n' -> output_string fd "\\n\"\n\""
    | c -> output_char fd c
  in
  let sorted_pot_strings = List.sort (fun (_, pos_a) (_, pos_b) -> compare pos_a pos_b)
      (Hashtbl.fold (fun k (v, _) l -> (k,v) :: l) pot_strings [] ) in
  List.iter (fun (s, _) ->
    match Hashtbl.find_all pot_strings s with
    | [] -> ()
    | l ->
	List.iter (fun _ -> Hashtbl.remove pot_strings s) l ;

	List.iter (fun po_comment -> output_string fd ("#. " ^ po_comment ^ "\n")) (collect snd l);

	let pos_l = List.sort compare (List.map fst l) in
	fprintf fd "#: %s\n" (String.concat " " (List.map Info.pos2s_for_po pos_l)) ;
	output_string fd "#, c-format\n" ;

	output_string fd (if String.contains s '\n' then "msgid \"\"\n\"" else "msgid \"") ;
	String.iter print_formatted_char s ;
	output_string fd "\"\n" ;
	output_string fd "msgstr \"\"\n\n"
  ) sorted_pot_strings ;      
  close_out fd

let check_system_call = function
  | "mkdir" :: l ->
      let has_p = List.exists (str_begins_with "-p") l in
      let has_m = List.exists (str_begins_with "-m") l in
      if has_p && has_m then ()
      else if has_p then warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace system(\"mkdir -p ...\") with mkdir_p(...)"
      else if has_m then warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace system(\"mkdir -m <mode> ...\") with mkdir(..., <mode>)"
      else warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace system(\"mkdir ...\") with mkdir(...)"
  | _ -> ()

let call_raw force_non_builtin_func (e, para) =
  let check_anonymous_block f = function
  | [ Anonymous_sub _ ; Deref (I_hash, _) ] ->
      warn_rule [Warn_strange] ("a hash is not a valid parameter to function " ^ f)

  | Anonymous_sub _ :: _ -> ()
  | _ -> warn_rule [Warn_complex_expressions] (sprintf "always use \"%s\" with a block (eg: %s { ... } @list)" f f)
  in

  match e with
  | Deref(I_func, Ident(None, f, _)) ->
      (match f with
      | "join" ->
	  (match un_parenthesize_full_l para with
	  | e :: _ when not (is_a_scalar e) -> warn_rule [Warn_traps] "first argument of join() must be a scalar";
	  | [_] -> warn_rule [Warn_traps] "not enough parameters"
	  | [_; e] when is_a_scalar e -> warn_rule [Warn_traps] "join('...', $foo) is the same as $foo"
	  | _ -> ())

      | "length" ->
	  if para = [] then warn_rule [Warn_complex_expressions] (sprintf "please use \"%s $_\" instead of \"%s\"" f f) else
	  if is_not_a_scalar (List.hd para) then warn_rule [Warn_traps] "never use \"length @l\", it returns the length of the string int(@l)" ;

      | "open" ->
	  (match para with
	  | [ List(Ident(None, name, _) :: _) ]
	  | Ident(None, name, _) :: _ ->
	      if not (List.mem name [ "STDIN" ; "STDOUT" ; "STDERR" ]) then
		warn_rule [Warn_complex_expressions] (sprintf "use a scalar instead of a bareword (eg: occurrences of %s with $%s)" name name)
	  | _ -> ())

      | "N" | "N_" ->
	  (match para with
	  | [ List(String([ s, List [] ], (_, pos_offset, _ as pos)) :: para) ] -> 
	      if !Flags.generate_pot then (
		Hashtbl.add pot_strings s (pos, !po_comments) ;
		po_comments := []
	      ) ;
	      let contexts = check_format_a_la_printf s pos_offset in
	      if f = "N" then
		if List.length para < List.length contexts then
		  warn_rule [Warn_traps; Warn_MDK_Common] "not enough parameters"
		else if List.length para > List.length contexts then
		  warn_rule [Warn_traps; Warn_MDK_Common] "too many parameters" ;
	      (*if String.contains s '\t' then warn_rule "tabulation in translated string must be written \\\\t";*)
	      (*if count_matching_char s '\n' > 10 then warn_rule "long string";*)
	  | [ List(String _ :: _) ] -> die_rule "don't use interpolated translated string, use %s or %d instead"
	  |  _ -> die_rule (sprintf "%s() must be used with a string" f))

      | "if_" ->
	  (match para with
	  | [ List [ _ ] ] -> warn_rule [Warn_traps; Warn_MDK_Common] "not enough parameters";
	  | _ -> ())

      | "map" ->
	  (match para with

	  | Anonymous_sub(None, Block [ List [ Call(Deref(I_func, Ident(None, "if_", _)),
						    [ List [ _ ; Deref(I_scalar, Ident(None, "_", _)) ] ]) ] ], _) :: _ ->
						      warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace \"map { if_(..., $_) }\" with \"grep { ... }\""
	  | _ -> check_anonymous_block f para)

      | "grep" ->
	  (match para with
	  | [ Anonymous_sub(None, Block [ List [ Call_op("not", [ Call(Deref(I_func, Ident(None, "member", _)), [ List(Deref(I_scalar, Ident(None, "_", _)) :: _) ]) ], _) ] ], _); _ ] ->
	      warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace \"grep { !member($_, ...) } @l\" with \"difference2([ @l ], [ ... ])\""
	  | [ Anonymous_sub(None, Block [ List [ Call(Deref(I_func, Ident(None, "member", _)), [ List(Deref(I_scalar, Ident(None, "_", _)) :: _) ]) ] ], _); _ ] ->
	      warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace \"grep { member($_, ...) } @l\" with \"intersection([ @l ], [ ... ])\""
	  | _ -> check_anonymous_block f para)

      | "any" ->
	  (match para with
	    [Anonymous_sub (None, Block 
			      [ List [ Call_op("eq", [Deref(I_scalar, Ident(None, "_", _)); _ ], _) ] ], 
			    _); _ ] ->
	      warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace \"any { $_ eq ... } @l\" with \"member(..., @l)\""
	  | _ -> check_anonymous_block f para)		

      | "grep_index" | "map_index" | "partition" | "uniq_"
      | "find"
      | "every"
      | "find_index"
      | "each_index" -> check_anonymous_block f para

      | "member" ->
	  (match para with
	    [ List [ _; Call(Deref(I_func, Ident(None, "keys", _)), _) ] ] ->
	      warn_rule [Warn_suggest_simpler; Warn_MDK_Common] "you can replace \"member($xxx, keys %yyy)\" with \"exists $yyy{$xxx}\""
	  | _ -> ())

      | "pop" | "shift" ->
	  (match para with
	  | [] 
	  | [ Deref(I_array, _) ] 
	  | [ List [ Deref(I_array, _) ] ] -> ()
	  | _ -> warn_rule [Warn_traps] (f ^ " is expecting an array and nothing else"))

      | "push" | "unshift" ->
	  (match para with
	  | Deref(I_array, _) :: l 
	  | [ List (Deref(I_array, _) :: l) ] -> 
	      if l = [] then warn_rule [Warn_traps] ("you must give some arguments to " ^ f)
	  | _ -> warn_rule [Warn_traps] (f ^ " is expecting an array"))

      | "system" ->
	  let fake_string_option_from_expr = function
	    | String(l, _) -> Some(String.concat "" (List.map fst l))
	    | Raw_string(s, _) -> Some s
	    | _ -> None
	  in
	  (match un_parenthesize_full_l para with
	  | [ e ] ->
	      (match fake_string_option_from_expr e with
	      | Some s ->
		  if List.exists (String.contains s) [ '\'' ; char_quote ] &&
	            not (List.exists (String.contains s) [ '<' ; '>' ; '&' ; ';']) then
		    warn_rule [Warn_complex_expressions] "instead of quoting parameters you should give a list of arguments";
		  check_system_call (split_at ' ' s)
	      | None -> ())
	  | l -> 
	      let l' = filter_some_with fake_string_option_from_expr l in
	      check_system_call l')
      | _ -> ()
      );

      let para' = match f with
      | "no" ->
	  (match para with
	  | [ Ident(_, _, pos) as s ] -> Some [ Raw_string(string_of_fromparser s, pos) ]
	  | [ Call(Deref(I_func, (Ident(_, _, pos) as s)), l) ] -> Some(Raw_string(string_of_fromparser s, pos) :: l)
	  | _ -> die_rule "use \"no PACKAGE <para>\"")
      | "undef" ->
	  (match para with
	  | [ Deref(I_star, ident) ] -> Some [ Deref(I_func, ident) ]
	  | _ -> None)

      | "goto" ->
	  (match para with
	  | [ Ident(None, s, pos) ] -> Some [ Raw_string(s, pos) ]
	  | _ -> None)

      | "last" | "next" | "redo" when not force_non_builtin_func ->
	  (match para with
	  | [ Ident(None, s, pos) ] -> Some [ Raw_string(s, pos) ]
	  | _ -> die_rule (sprintf "%s must be used with a raw string" f))

      | "split" ->
	  (match para with
	  | [ List(Call_op("m//", Deref(I_scalar, Ident(None, "_", _)) :: pattern, pos) :: l) ]
	  | Call_op("m//", Deref(I_scalar, Ident(None, "_", _)) :: pattern, pos) :: l ->
	      Some(Call_op("qr//", pattern, pos) :: l)
	  | _ -> None)
	    
      | _ -> None
      in Call(e, some_or para' para)
  | _ -> Call(e, para)

let call(e, para) = call_raw false (e, para)

let check_return esp_func esp_para =
  match esp_func.any with
  | Ident(None, "return", _) -> 
      prio_lo_check P_call_no_paren esp_para.any.priority esp_para.pos (List esp_para.any.expr)
  | _ -> ()

let call_and_context(e, para) force_non_builtin_func priority esp_start esp_end =
  let context = 
    match e with
    | Deref(I_func, Ident(None, f, _)) -> function_to_context false f
    | _ -> M_unknown
  in
  new_pesp context priority (call_raw force_non_builtin_func (e, para)) esp_start esp_end

let call_no_paren   esp_func esp_para = check_return esp_func esp_para; call_and_context(Deref(I_func, esp_func.any), esp_para.any.expr) false P_call_no_paren esp_func esp_para
let call_with_paren esp_func esp_para = check_return esp_func esp_para; call_and_context (Deref(I_func, esp_func.any), esp_para.any.expr) false P_tok esp_func esp_para

let call_func esp_func esp_para = 
  call_and_context(esp_func.any, esp_para.any.expr) true P_tok esp_func esp_para

let call_one_scalar_para prio { any = e ; pos = pos } para esp_start esp_end =
  let para' =
    match para with
    | [] ->
	  if e = "shift" || e = "pop" then 
	    [] (* can't decide here *)
	  else
	    (if not (List.mem e [ "length" ]) then warn_rule [Warn_complex_expressions] (sprintf "please use \"%s $_\" instead of \"%s\"" e e) ;
	     [var_dollar_ (raw_pos2pos pos)])
    | _ -> para
  in
  new_pesp M_unknown prio (call(Deref(I_func, Ident(None, e, raw_pos2pos pos)), para')) esp_start esp_end


let (current_lexbuf : Lexing.lexbuf option ref) = ref None

let rec list2tokens l =
  let rl = ref l in
  fun lexbuf ->
    match !rl with
    | [] -> internal_error "list2tokens"
    | ((start, end_), e) :: l -> 
	(* HACK: fake a normal lexbuf *)
	lexbuf.Lexing.lex_start_p <- { Lexing.dummy_pos with Lexing.pos_cnum = start } ;
	lexbuf.Lexing.lex_curr_p <- { Lexing.dummy_pos with Lexing.pos_cnum = end_ } ;
	rl := l ; e

let parse_tokens parse tokens lexbuf_opt =
  if lexbuf_opt <> None then current_lexbuf := lexbuf_opt ;
  if tokens = [] then [] else
  parse (list2tokens tokens) (some !current_lexbuf)

let parse_interpolated parse l = 
  let l' = List.map (fun (s, tokens) -> s, to_List(parse_tokens parse tokens None)) l in
  match split_last l' with
  | pl, ("", List []) -> pl
  | _ -> l'

let to_String parse strict { any = l ; pos = pos } = 
  let l' = parse_interpolated parse l in
  (match l' with
  | [ "", List [Deref(I_scalar, Ident(None, ident, _))]] -> 
      if ident <> "!" && strict then warn [Warn_suggest_simpler] pos (sprintf "%s is better written without the double quotes" (variable2s(I_scalar, ident)))
  | [ "", List [Deref(I_hash, _)]] -> 
      warn [Warn_traps] pos "don't use a hash in string context"
  | [ "", List [Deref(I_array, _)]]
  | [ "", List [Deref_with(I_array, I_array, _, _)]] -> (* for slices like: "@m3[1..$#m3]" *)
      ()
  | [("", _)] -> 
      if strict then warn [Warn_suggest_simpler] pos "double quotes are unneeded"
  | _ -> ());
  String(l', raw_pos2pos pos)

let from_PATTERN parse { any = (s, opts) ; pos = pos } = 
  let re = parse_interpolated parse s in
  (match List.rev re with
  | (s, List []) :: _ ->
      if str_ends_with s ".*" then
	warn_rule [Warn_suggest_simpler] (sprintf "you can remove \"%s\" at the end of your regexp" ".*")
      else if str_ends_with s ".*$" then
	warn_rule [Warn_suggest_simpler] (sprintf "you can remove \"%s\" at the end of your regexp" ".*$")
  | _ -> ());
  let pattern = [ String(re, raw_pos2pos pos) ; Raw_string(opts, raw_pos2pos pos) ] in
  check_simple_pattern pattern;
  pattern

let from_PATTERN_SUBST parse { any = (s1, s2, opts) ; pos = pos } = 
  [ String(parse_interpolated parse s1, raw_pos2pos pos) ; 
    String(parse_interpolated parse s2, raw_pos2pos pos) ; 
    Raw_string(opts, raw_pos2pos pos) ]


let rec mcontext2s = function
  | M_none -> "()"

  | M_bool -> "bool"

  | M_int -> "int"
  | M_float -> "float"
  | M_string -> "string"
  | M_ref c -> "ref(" ^ mcontext2s c ^ ")"
  | M_revision -> "revision"
  | M_undef -> "undef"
  | M_sub -> "sub"
  | M_unknown_scalar -> "scalar"

  | M_tuple l -> "tuple(" ^ String.concat ", " (List.map mcontext2s l) ^ ")"
  | M_list -> "list"
  | M_array -> "array"
  | M_hash -> "hash"

  | M_special -> "special"
  | M_unknown -> "unknown"
  | M_mixed l -> String.concat " | " (List.map mcontext2s l)

let rec mcontext_lower c1 c2 =
  match c1, c2 with
  | M_special, _ | _, M_special -> internal_error "M_special in mcontext_compare"

  | M_unknown, _
  | _, M_unknown -> true

  | M_mixed l, c -> List.exists (fun a -> mcontext_lower a c) l
  | c, M_mixed l -> List.exists (mcontext_lower c) l

  | M_none, M_none | M_sub, M_sub | M_hash, M_hash | M_hash, M_bool -> true
  | M_none, _      | M_sub, _     | M_hash, _      -> false

  | _, M_list -> true

  | M_list, M_bool
  | M_list, M_tuple _

    (* M_unknown_scalar is M_mixed [ M_int ; M_float ; M_string ; M_bool ; M_ref _ ; M_revision ; M_undef ] *)
  | M_unknown_scalar, M_int | M_unknown_scalar, M_float | M_unknown_scalar, M_string | M_unknown_scalar, M_bool 
  | M_unknown_scalar, M_ref _ | M_unknown_scalar, M_revision | M_unknown_scalar, M_undef | M_unknown_scalar, M_unknown_scalar

  | M_array, M_array | M_array, M_int | M_array, M_float | M_array, M_bool | M_array, M_unknown_scalar | M_array, M_tuple _
  | M_int, M_int | M_int, M_float | M_int, M_string | M_int, M_bool | M_int, M_unknown_scalar
  | M_float, M_float | M_float, M_string | M_float, M_bool | M_float, M_unknown_scalar
  | M_string, M_string | M_string, M_bool | M_string, M_unknown_scalar
  | M_bool, M_bool | M_bool, M_unknown_scalar

  | M_ref _, M_unknown_scalar
  | M_revision, M_revision | M_revision, M_unknown_scalar
  | M_undef, M_undef | M_undef, M_unknown_scalar

    -> true

  | M_tuple t1, M_tuple t2 -> 
      List.length t1 = List.length t2 && for_all2_true mcontext_lower t1 t2

  | M_tuple [c], M_int | M_tuple [c], M_float | M_tuple [c], M_string | M_tuple [c], M_bool 
  | M_tuple [c], M_ref _ | M_tuple [c], M_revision | M_tuple [c], M_undef | M_tuple [c], M_unknown_scalar 
    -> mcontext_lower c c2

(*  | M_ref a, M_ref b -> mcontext_lower a b *)

  | _ -> false

let mcontext_is_scalar = function
  | M_unknown -> false
  | c -> mcontext_lower c M_unknown_scalar

let mcontext_to_scalar = function
  | M_array -> M_int
  | c -> if mcontext_is_scalar c then c else M_unknown_scalar

let mcontext_merge_raw c1 c2 =
  match c1, c2 with
  | M_unknown, _ | _, M_unknown -> Some M_unknown
  | M_unknown_scalar, c when mcontext_is_scalar c -> Some M_unknown_scalar
  | c, M_unknown_scalar when mcontext_is_scalar c -> Some M_unknown_scalar
  | M_mixed _, _ | _, M_mixed _ -> internal_error "mcontext_merge_raw"
  | _ -> 
      if mcontext_lower c1 c2 then Some c2 else
      if mcontext_lower c2 c1 then Some c1 else
      if c1 = c2 then Some c1 else
      None

let rec mcontext_lmerge_add l = function
  | M_mixed l2 -> List.fold_left mcontext_lmerge_add [] (l2 @ l)
  | c ->
      let rec add_to = function
	| [] -> [c]
	| M_mixed subl :: l -> add_to (subl @ l)
	| c2 :: l ->
	    match mcontext_merge_raw c c2 with
	    | Some c' -> c' :: l
	    | None -> c2 :: add_to l
      in add_to l

let mcontext_lmerge l =
  match List.fold_left mcontext_lmerge_add [] l with
  | [] -> internal_error "mcontext_lmerge"
  | [c] -> c
  | l -> M_mixed l

let mcontext_merge c1 c2 = mcontext_lmerge [ c1 ; c2 ]

let mcontext_lmaybe esp = if esp.any = [] then [] else [esp.mcontext]

let mcontext_check_raw wanted_mcontext mcontext =
  if not (mcontext_lower mcontext wanted_mcontext) then
    warn_rule [Warn_context] (sprintf "context %s is not compatible with context %s" (mcontext2s mcontext) (mcontext2s wanted_mcontext))

let mcontext_check wanted_mcontext esp =
  (match wanted_mcontext with
  | M_list | M_array | M_float | M_mixed [M_array; M_none] | M_tuple _ -> ()
  | _ ->
    match un_parenthesize_full esp.any.expr with
    | Call(Deref(I_func, Ident(None, "grep", _)), _) -> 
	warn_rule [Warn_suggest_simpler; Warn_help_perl_checker] (if wanted_mcontext = M_bool then
	  "in boolean context, use \"any\" instead of \"grep\"" else
	  "you may use \"find\" instead of \"grep\"")
    | _ -> ());
  mcontext_check_raw wanted_mcontext esp.mcontext

let mcontext_check_unop_l wanted_mcontext esp = 
  mcontext_check wanted_mcontext { esp with any = { esp.any with expr = List esp.any.expr  } }

let mcontext_check_non_none esp =
  if esp.mcontext = M_none then warn_rule [Warn_context] "() context not accepted here"

let mcontext_check_none msg expr esp =
  let rec mcontext_check_none_rec msg expr = function
    | M_none | M_unknown -> ()
    | M_mixed l when List.exists (fun c -> c = M_none) l -> ()
    | M_tuple l ->
	(match expr with
	| [Block [List l_expr]]
	| [List l_expr]
	| [List l_expr ; Semi_colon] ->
	    let rec iter = function
	      | e::l_expr, mcontext::l ->
		  mcontext_check_none_rec (if l = [] then msg else "value is dropped") [e] mcontext ;
		  iter (l_expr, l)
	      | [], [] -> ()
	      | _ -> internal_error "mcontext_check_none"
	    in iter (un_parenthesize_full_l l_expr, l)
	| _ -> internal_error "mcontext_check_none")
    | _ -> 
	match expr with
	| [List [Num("1", _)]; Semi_colon] -> () (* allow "1;" for package return value. It would be much better to check we are at toplevel, but hell i don't want to wire this information up to here *)
	| [List [Call_op ("<>", [Ident (None, "STDIN", _)], _)]; Semi_colon] -> () (* allow <STDIN> to ask "press return" *)
	| [List [Call(Deref(I_func, Ident(None, "map", _)), _)]; Semi_colon] -> warn_rule [Warn_void] "if you don't use the return value, use \"foreach\" instead of \"map\""
	| _ -> warn [Warn_void] esp.pos msg
  in
  mcontext_check_none_rec msg expr esp.mcontext

(* only returns M_float when there is at least one float *)
let mcontext_float_or_int l = 
  List.iter (mcontext_check_raw M_float) l;
  if List.mem M_float l then M_float else M_int 

let mcontext_op_assign left right =
  mcontext_check_non_none right;

  let left_mcontext =
    match left.mcontext with
    | M_mixed [ c ; M_none ] -> c
    | c -> c
  in

  let wanted_mcontext = match left_mcontext with
  | M_array -> M_list
  | M_hash -> M_mixed [ M_hash ; M_list ]
  | m -> m
  in
  mcontext_check wanted_mcontext right;

  let return_mcontext =
    match left_mcontext with
    | M_tuple _ -> M_array
    | c -> c
  in
  mcontext_merge return_mcontext M_none

let mtuple_context_concat c1 c2 =
  match c1, c2 with
  | M_array, _ | _, M_array
  | M_hash, _ | _, M_hash -> M_list
  | M_tuple l, _ -> M_tuple (l @ [c2])
  | _ -> M_tuple [c1 ; c2]

let call_op_if_infix left right esp_start esp_end =
  (match left, right with
  | List [Call_op("=", [Deref(context, _); _], _)], _ when non_scalar_context context -> ()
  | List [Call_op("=", [v; _], _)],
    List [Call_op("not", [v'], _)] when is_same_fromparser v v' ->
      warn_rule [Warn_suggest_simpler] "\"$foo = ... if !$foo\" can be written \"$foo ||= ...\""
  | _ -> ());

  mcontext_check_none "value is dropped" [left] esp_start;
  (match right with 
  | List [ Num("0", _)] -> () (* allow my $x if 0 *)
  | _ -> check_My_under_condition "replace \"my $foo = ... if <cond>\" with \"my $foo = <cond> && ...\"" left);

  let pos = raw_pos_range esp_start esp_end in
  new_any M_none (Call_op("if infix", [ left ; right], raw_pos2pos pos)) esp_start.spaces pos

let call_op_unless_infix left right esp_start esp_end =
  (match left, right with
  | List [Call_op("=", [Deref(context, _); _], _)], _ when non_scalar_context context -> ()
  | List [Call_op("=", [v; _], _)], List [v'] when is_same_fromparser v v' ->
      warn_rule [Warn_suggest_simpler] "\"$foo = ... unless $foo\" can be written \"$foo ||= ...\""
  | _ -> ());
  (match right with
  | List [Call_op(op, _, _)] ->
      (match op with
      | "&&" | "||" | "not" | "ne" | "?:" -> warn_rule [Warn_complex_expressions] "don't use \"unless\" when the condition is complex, use \"if\" instead"
      | _ -> ());
  | _ -> ());

  mcontext_check_none "value is dropped" [left] esp_start;
  check_My_under_condition "replace \"my $foo = ... unless <cond>\" with \"my $foo = !<cond> && ...\"" left;

  let pos = raw_pos_range esp_start esp_end in
  new_any M_none (Call_op("unless infix", [ left ; right], raw_pos2pos pos)) esp_start.spaces pos

let symops pri para_context return_context op_str left op right =
  sp_same op right;
  let skip_context_check =
    (op_str = "==" || op_str = "!=") && (match left.any.expr, right.any.expr with
    | Deref(I_array, _), List [] -> true (* allow @l == () and @l != () *)
    | _ -> false)
  in
  if op_str <> "==" && op_str <> "!=" && para_context = M_float then
    (match un_parenthesize_full left.any.expr with
    | Call_op("last_array_index", _, _) -> warn_rule [Warn_complex_expressions] "change your expression to use @xxx instead of $#xxx"
    | _ -> ());

  if not skip_context_check then
    (mcontext_check para_context left ; mcontext_check para_context right) ;
  to_Call_op_ return_context pri op_str [prio_lo pri left; prio_lo_after pri right] left right