File: gvars.c

package info (click to toggle)
gap 4r8p6-2
  • links: PTS
  • area: main
  • in suites: stretch
  • size: 33,476 kB
  • ctags: 7,663
  • sloc: ansic: 108,841; xml: 47,807; sh: 3,628; perl: 2,342; makefile: 796; asm: 62; awk: 6
file content (1258 lines) | stat: -rw-r--r-- 43,086 bytes parent folder | download | duplicates (4)
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
/****************************************************************************
**
*W  gvars.c                     GAP source                   Martin Schönert
**
**
*Y  Copyright (C)  1996,  Lehrstuhl D für Mathematik,  RWTH Aachen,  Germany
*Y  (C) 1998 School Math and Comp. Sci., University of St Andrews, Scotland
*Y  Copyright (C) 2002 The GAP Group
**
**  This file contains the functions of the global variables package.
**
**  The global variables  package  is the   part of the  kernel that  manages
**  global variables, i.e., the global namespace.  A global variable binds an
**  identifier to a value.
**
**  A global variable can be automatic.   That means that the global variable
**  binds the  identifier to a function and  an argument.   When the value of
**  the global variable is needed, the  function is called with the argument.
**  This function call  should, as a side-effect, execute  an assignment of a
**  value to the global variable, otherwise an error is signalled.
**
**  A global variable can have a number of internal copies, i.e., C variables
**  that always reference the same value as the global variable.
**  It can also have a special type of internal copy (a fopy) only used for
**  functions,  where  the internal copies
**  only reference the same value as the global variable if it is a function.
**  Otherwise the internal copies reference functions that signal an error.
*/
#include        "system.h"              /* Ints, UInts                     */


#include        "gasman.h"              /* garbage collector               */
#include        "objects.h"             /* objects                         */

#include        "scanner.h"             /* scanner                         */

#include        "gap.h"                 /* error handling, initialisation  */

#include        "code.h"                /* coder                           */

#include        "gvars.h"               /* global variables                */

#include        "calls.h"               /* generic call mechanism          */

#include        "records.h"             /* generic records                 */
#include        "precord.h"             /* plain records                   */

#include        "lists.h"               /* generic lists                   */

#include        "plist.h"               /* plain lists                     */
#include        "string.h"              /* strings                         */

#include        "bool.h"                /* booleans                        */

#include        "tls.h"                 /* thread-local storage            */
#include        "thread.h"              /* threads                         */
#include        "aobjects.h"            /* atomic objects                  */

/****************************************************************************
**
*V  ValGVars  . . . . . . . . . . . . . . . . . .  values of global variables
*V  PtrGVars  . . . . . . . . . . . . . pointer to values of global variables
**
**  'ValGVars' is the bag containing the values of the global variables.
**
**  'PtrGVars' is a pointer  to the 'ValGVars'  bag.  This makes it faster to
**  access global variables.
**
**  Since a   garbage  collection may move   this  bag around,    the pointer
**  'PtrGVars' must be  revalculated afterwards.   This  should be done by  a
**  function in this package, but is still done in 'VarsAfterCollectBags'.
*/
Obj   ValGVars;

Obj * PtrGVars;


/****************************************************************************
**
*F  VAL_GVAR(<gvar>)  . . . . . . . . . . . . . . .  value of global variable
**
**  'VAL_GVAR' returns the  value of the global  variable  <gvar>.  If <gvar>
**  has no  assigned value, 'VAL_GVAR' returns 0.   In this case <gvar> might
**  be an automatic global variable, and one should call 'ValAutoGVar', which
**  will return the value of <gvar>  after evaluating <gvar>-s expression, or
**  0 if <gvar> was not an automatic variable.
**
**  'VAL_GVAR' is defined in the declaration part of this package as follows
**
#define VAL_GVAR(gvar)          PtrGVars[ (gvar) ]
*/


/****************************************************************************
**
*V  NameGVars . . . . . . . . . . . . . . . . . . . names of global variables
*V  WriteGVars  . . . . . . . . . . . . .  writable flags of global variables
*V  ExprGVars . . . . . . . . . .  expressions for automatic global variables
*V  CopiesGVars . . . . . . . . . . . . . internal copies of global variables
*V  FopiesGVars . . . . . . . .  internal function copies of global variables
*V  CountGVars  . . . . . . . . . . . . . . . . .  number of global variables
*/
Obj             NameGVars;
Obj             WriteGVars;
Obj             ExprGVars;
Obj             CopiesGVars;
Obj             FopiesGVars;
UInt            CountGVars;


/****************************************************************************
**
*V  TableGVars  . . . . . . . . . . . . . .  hashed table of global variables
*V  SizeGVars . . . . . . .  current size of hashed table of global variables
*/
Obj             TableGVars;
UInt            SizeGVars;


/****************************************************************************
**
*V  ErrorMustEvalToFuncFunc . . . . . . . . .  function that signals an error
*F  ErrorMustEvalToFuncHandler(<self>,<args>) . handler that signals an error
**
**  'ErrorMustEvalToFuncFunc' is a (variable number of  args)  function  that
**  signals the error ``Function: <func> be a function''.
**
**  'ErrorMustEvalToFuncHandler'  is  the  handler  that  signals  the  error
**  ``Function: <func> must be a function''.
*/
Obj             ErrorMustEvalToFuncFunc;

Obj             ErrorMustEvalToFuncHandler (
    Obj                 self,
    Obj                 args )
{
    ErrorQuit(
        "Function Calls: <func> must be a function",
        0L, 0L );
    return 0;
}


/****************************************************************************
**
*V  ErrorMustHaveAssObjFunc . . . . . . . . .  function that signals an error
*F  ErrorMustHaveAssObjHandler(<self>,<args>) . handler that signals an error
**
**  'ErrorMustHaveAssObjFunc' is a (variable number of  args)  function  that
**  signals the error ``Variable: <<unknown>> must have an assigned value''.
**
**  'ErrorMustHaveAssObjHandler'  is  the  handler  that  signals  the  error
**  ``Variable: <<unknown>> must have an assigned value''.
*/
Obj             ErrorMustHaveAssObjFunc;

Obj             ErrorMustHaveAssObjHandler (
    Obj                 self,
    Obj                 args )
{
    ErrorQuit(
        "Variable: <<unknown>> must have an assigned value",
        0L, 0L );
    return 0;
}


/****************************************************************************
**
*F  AssGVar(<gvar>,<val>) . . . . . . . . . . . . assign to a global variable
**
**  'AssGVar' assigns the value <val> to the global variable <gvar>.
*/

static Obj REREADING;                   /* Copy of GAP global variable REREADING */

void            AssGVar (
    UInt                gvar,
    Obj                 val )
{
    Obj                 cops;           /* list of internal copies         */
    Obj *               copy;           /* one copy                        */
    UInt                i;              /* loop variable                   */
    Obj                 onam;           /* object of <name>                */

    /* make certain that the variable is not read only                     */
    while ( (REREADING != True) &&
            (ELM_PLIST( WriteGVars, gvar ) == INTOBJ_INT(0)) ) {
        ErrorReturnVoid(
            "Variable: '%s' is read only",
            (Int)CSTR_STRING( ELM_PLIST(NameGVars,gvar) ), 0L,
            "you can 'return;' after making it writable" );
    }

    /* assign the value to the global variable                             */
    VAL_GVAR(gvar) = val;
    CHANGED_BAG( ValGVars );

    /* if the global variable was automatic, convert it to normal          */
    SET_ELM_PLIST( ExprGVars, gvar, 0 );

    /* assign the value to all the internal copies                         */
    cops = ELM_PLIST( CopiesGVars, gvar );
    if ( cops != 0 ) {
        for ( i = 1; i <= LEN_PLIST(cops); i++ ) {
            copy  = (Obj*) ELM_PLIST(cops,i);
            *copy = val;
        }
    }

    /* if the value is a function, assign it to all the internal fopies    */
    cops = ELM_PLIST( FopiesGVars, gvar );
    if ( cops != 0 && val != 0 && TNUM_OBJ(val) == T_FUNCTION ) {
        for ( i = 1; i <= LEN_PLIST(cops); i++ ) {
            copy  = (Obj*) ELM_PLIST(cops,i);
            *copy = val;
        }
    }

    /* if the values is not a function, assign the error function          */
    else if ( cops != 0 && val != 0 /* && TNUM_OBJ(val) != T_FUNCTION */ ) {
        for ( i = 1; i <= LEN_PLIST(cops); i++ ) {
            copy  = (Obj*) ELM_PLIST(cops,i);
            *copy = ErrorMustEvalToFuncFunc;
        }
    }

    /* if this was an unbind, assign the other error function              */
    else if ( cops != 0 /* && val == 0 */ ) {
        for ( i = 1; i <= LEN_PLIST(cops); i++ ) {
            copy  = (Obj*) ELM_PLIST(cops,i);
            *copy = ErrorMustHaveAssObjFunc;
        }
    }

    /* assign name to a function                                           */
    if ( val != 0 && TNUM_OBJ(val) == T_FUNCTION && NAME_FUNC(val) == 0 ) {
        onam = CopyToStringRep(NameGVarObj(gvar));
        RESET_FILT_LIST( onam, FN_IS_MUTABLE );
        NAME_FUNC(val) = onam;
        CHANGED_BAG(val);
    }
}


/****************************************************************************
**
*F  ValAutoGVar(<gvar>) . . . . . . . .  value of a automatic global variable
**
**  'ValAutoGVar' returns the value of the global variable <gvar>.  This will
**  be 0 if  <gvar> has  no assigned value.    It will also cause a  function
**  call, if <gvar> is automatic.
*/
Obj             ValAutoGVar (
    UInt                gvar )
{
    Obj                 func;           /* function to call for automatic  */
    Obj                 arg;            /* argument to pass for automatic  */

    /* if this is an automatic variable, make the function call            */
    if ( VAL_GVAR(gvar) == 0 && ELM_PLIST( ExprGVars, gvar ) != 0 ) {

        /* make the function call                                          */
        func = ELM_PLIST( ELM_PLIST( ExprGVars, gvar ), 1 );
        arg  = ELM_PLIST( ELM_PLIST( ExprGVars, gvar ), 2 );
        CALL_1ARGS( func, arg );

        /* if this is still an automatic variable, this is an error        */
        while ( VAL_GVAR(gvar) == 0 ) {
            ErrorReturnVoid(
       "Variable: automatic variable '%s' must get a value by function call",
                (Int)CSTR_STRING( ELM_PLIST(NameGVars,gvar) ), 0L,
                "you can 'return;' after assigning a value" );
        }

    }

    /* return the value                                                    */
    return VAL_GVAR(gvar);
}


/****************************************************************************
**
*F  NameGVar(<gvar>)  . . . . . . . . . . . . . . . name of a global variable
**
**  'NameGVar' returns the name of the global variable <gvar> as a C string.
*/
Char *          NameGVar (
    UInt                gvar )
{
    return CSTR_STRING( ELM_PLIST( NameGVars, gvar ) );
}

Obj NameGVarObj ( UInt gvar )
{
    return ELM_PLIST( NameGVars, gvar );
}

#define NSCHAR '@'

Obj CurrNamespace = 0;

Obj FuncSET_NAMESPACE(Obj self, Obj str)
{
    TLS(CurrNamespace) = str;
    return 0;
}

Obj FuncGET_NAMESPACE(Obj self)
{
    return TLS(CurrNamespace);
}

/****************************************************************************
**
*F  GVarName(<name>)  . . . . . . . . . . . . . .  global variable for a name
**
**  'GVarName' returns the global variable with the name <name>.
*/
UInt GVarName ( 
    const Char *        name )
{
    Obj                 gvar;           /* global variable (as imm intval) */
    Char                gvarbuf[1024];  /* temporary copy for namespace    */
    Char *              cns;            /* Pointer to current namespace    */
    UInt                pos;            /* hash position                   */
    Char                namx [1024];    /* temporary copy of <name>        */
    Obj                 string;         /* temporary string value <name>   */
    Obj                 table;          /* temporary copy of <TableGVars>  */
    Obj                 gvar2;          /* one element of <table>          */
    const Char *        p;              /* loop variable                   */
    UInt                i;              /* loop variable                   */
    Int                 len;            /* length of name                  */

    /* First see whether it could be namespace-local: */
    cns = CSTR_STRING(TLS(CurrNamespace));
    if (*cns) {   /* only if a namespace is set */
        len = strlen(name);
        if (name[len-1] == NSCHAR) {
            strlcpy(gvarbuf, name, 512);
            strlcat(gvarbuf, cns, sizeof(gvarbuf));
            name = gvarbuf;
        }
    }

    /* start looking in the table at the following hash position           */
    pos = 0;
    for ( p = name; *p != '\0'; p++ ) {
        pos = 65599 * pos + *p;
    }
    pos = (pos % SizeGVars) + 1;

    /* look through the table until we find a free slot or the global      */
    while ( (gvar = ELM_PLIST( TableGVars, pos )) != 0
         && strncmp( NameGVar( INT_INTOBJ(gvar) ), name, 1023 ) ) {
        pos = (pos % SizeGVars) + 1;
    }

    /* if we did not find the global variable, make a new one and enter it */
    /* (copy the name first, to avoid a stale pointer in case of a GC)     */
    if ( gvar == 0 ) {
        CountGVars++;
        gvar = INTOBJ_INT(CountGVars);
        SET_ELM_PLIST( TableGVars, pos, gvar );
        strlcpy(namx, name, sizeof(namx));
        C_NEW_STRING_DYN(string, namx);

        RESET_FILT_LIST( string, FN_IS_MUTABLE );
        GROW_PLIST(    ValGVars,    CountGVars );
        SET_LEN_PLIST( ValGVars,    CountGVars );
        SET_ELM_PLIST( ValGVars,    CountGVars, 0 );
        GROW_PLIST(    NameGVars,   CountGVars );
        SET_LEN_PLIST( NameGVars,   CountGVars );
        SET_ELM_PLIST( NameGVars,   CountGVars, string );
        CHANGED_BAG(   NameGVars );
        GROW_PLIST(    WriteGVars,  CountGVars );
        SET_LEN_PLIST( WriteGVars,  CountGVars );
        SET_ELM_PLIST( WriteGVars,  CountGVars, INTOBJ_INT(1) );
        GROW_PLIST(    ExprGVars,   CountGVars );
        SET_LEN_PLIST( ExprGVars,   CountGVars );
        SET_ELM_PLIST( ExprGVars,   CountGVars, 0 );
        GROW_PLIST(    CopiesGVars, CountGVars );
        SET_LEN_PLIST( CopiesGVars, CountGVars );
        SET_ELM_PLIST( CopiesGVars, CountGVars, 0 );
        GROW_PLIST(    FopiesGVars, CountGVars );
        SET_LEN_PLIST( FopiesGVars, CountGVars );
        SET_ELM_PLIST( FopiesGVars, CountGVars, 0 );
        PtrGVars = ADDR_OBJ( ValGVars );
    }

    /* if the table is too crowed, make a larger one, rehash the names     */
    if ( SizeGVars < 3 * CountGVars / 2 ) {
        table = TableGVars;
        SizeGVars = 2 * SizeGVars + 1;
        TableGVars = NEW_PLIST( T_PLIST, SizeGVars );
        SET_LEN_PLIST( TableGVars, SizeGVars );
        for ( i = 1; i <= (SizeGVars-1)/2; i++ ) {
            gvar2 = ELM_PLIST( table, i );
            if ( gvar2 == 0 )  continue;
            pos = 0;
            for ( p = NameGVar( INT_INTOBJ(gvar2) ); *p != '\0'; p++ ) {
                pos = 65599 * pos + *p;
            }
            pos = (pos % SizeGVars) + 1;
            while ( ELM_PLIST( TableGVars, pos ) != 0 ) {
                pos = (pos % SizeGVars) + 1;
            }
            SET_ELM_PLIST( TableGVars, pos, gvar2 );
        }
    }

    /* return the global variable                                          */
    return INT_INTOBJ(gvar);
}

/****************************************************************************
**

*V  Tilde . . . . . . . . . . . . . . . . . . . . . . . . global variable '~'
**
**  'Tilde' is  the global variable '~', the  one used in expressions such as
**  '[ [ 1, 2 ], ~[1] ]'.
**
**  Actually  when such expressions  appear in functions, one should probably
**  use a local variable.  But for now this is good enough.
*/
UInt Tilde;


/****************************************************************************
**
*F  MakeReadOnlyGVar( <gvar> )  . . . . . .  make a global variable read only
*/
void MakeReadOnlyGVar (
    UInt                gvar )
{       
    SET_ELM_PLIST( WriteGVars, gvar, INTOBJ_INT(0) );
    CHANGED_BAG(WriteGVars)
}


/****************************************************************************
**
*F  MakeReadOnlyGVarHandler(<self>,<name>)   make a global variable read only
**
**  'MakeReadOnlyGVarHandler' implements the function 'MakeReadOnlyGVar'.
**
**  'MakeReadOnlyGVar( <name> )'
**
**  'MakeReadOnlyGVar' make the global  variable with the name <name>  (which
**  must be a GAP string) read only.
*/
Obj MakeReadOnlyGVarHandler (
    Obj                 self,
    Obj                 name )
{       
    /* check the argument                                                  */
    while ( ! IsStringConv( name ) ) {
        name = ErrorReturnObj(
            "MakeReadOnlyGVar: <name> must be a string (not a %s)",
            (Int)TNAM_OBJ(name), 0L,
            "you can return a string for <name>" );
    }

    /* get the variable and make it read only                              */
    MakeReadOnlyGVar(GVarName(CSTR_STRING(name)));

    /* return void                                                         */
    return 0;
}


/****************************************************************************
**
*F  MakeReadWriteGVar( <gvar> ) . . . . . . make a global variable read write
*/
void MakeReadWriteGVar (
    UInt                gvar )
{
    SET_ELM_PLIST( WriteGVars, gvar, INTOBJ_INT(1) );
    CHANGED_BAG(WriteGVars)
}


/****************************************************************************
**
*F  MakeReadWriteGVarHandler(<self>,<name>) make a global variable read write
**
**  'MakeReadWriteGVarHandler' implements the function 'MakeReadWriteGVar'.
**
**  'MakeReadWriteGVar( <name> )'
**
**  'MakeReadWriteGVar' make the global  variable with the name <name>  (which
**  must be a GAP string) read and writable.
*/
Obj MakeReadWriteGVarHandler (
    Obj                 self,
    Obj                 name )
{
    /* check the argument                                                  */
    while ( ! IsStringConv( name ) ) {
        name = ErrorReturnObj(
            "MakeReadWriteGVar: <name> must be a string (not a %s)",
            (Int)TNAM_OBJ(name), 0L,
            "you can return a string for <name>" );
    }

    /* get the variable and make it read write                             */
    MakeReadWriteGVar(GVarName(CSTR_STRING(name)));

    /* return void                                                         */
    return 0;
}

/****************************************************************************
**
*F  IsReadOnlyGVar( <gvar> ) . . . . . . return status of a global variable
*/
Int IsReadOnlyGVar (
    UInt                gvar )
{
  return !INT_INTOBJ(ELM_PLIST(WriteGVars, gvar));
}


/****************************************************************************
**
*F  FuncIsReadOnlyGVar( <name> ) . . .handler for GAP function
**
*/

static Obj FuncIsReadOnlyGVar (
    Obj                 self,
    Obj                 name )
{
    /* check the argument                                                  */
    while ( ! IsStringConv( name ) ) {
        name = ErrorReturnObj(
            "IsReadOnlyGVar: <name> must be a string (not a %s)",
            (Int)TNAM_OBJ(name), 0L,
            "you can return a string for <name>" );
    }

    /* get the answer                             */
    return IsReadOnlyGVar(GVarName(CSTR_STRING(name))) ? True : False;
}


/****************************************************************************
**
*F  AUTOHandler() . . . . . . . . . . . . .   make automatic global variables
**
**  'AUTOHandler' implements the internal function 'AUTO'.
**
**  'AUTO( <func>, <arg>, <name1>, ... )'
**
**  'AUTO' makes   the global variables,  whose  names are given  the strings
**  <name1>, <name2>, ..., automatic.  That means  that when the value of one
**  of  those global  variables  is requested,  then  the function  <func> is
**  called and the  argument <arg>  is passed.   This function  call  should,
**  cause the execution  of an assignment to  that global variable, otherwise
**  an error is signalled.
*/
Obj             AUTOFunc;

Obj             AUTOHandler (
    Obj                 self,
    Obj                 args )
{
    Obj                 func;           /* the function to call            */
    Obj                 arg;            /* the argument to pass            */
    Obj                 list;           /* function and argument list      */
    Obj                 name;           /* one name (as a GAP string)      */
    UInt                gvar;           /* one global variable             */
    UInt                i;              /* loop variable                   */

    /* check that there are enough arguments                               */
    if ( LEN_LIST(args) < 2 ) {
        ErrorQuit(
            "usage: AUTO( <func>, <arg>, <name1>... )",
            0L, 0L );
        return 0;
    }

    /* get and check the function                                          */
    func = ELM_LIST( args, 1 );
    while ( TNUM_OBJ(func) != T_FUNCTION ) {
        func = ErrorReturnObj(
            "AUTO: <func> must be a function (not a %s)",
            (Int)TNAM_OBJ(func), 0L,
            "you can return a function for <func>" );
    }

    /* get the argument                                                    */
    arg = ELM_LIST( args, 2 );

    /* make the list of function and argument                              */
    list = NEW_PLIST( T_PLIST, 2 );
    SET_LEN_PLIST( list, 2 );
    SET_ELM_PLIST( list, 1, func );
    SET_ELM_PLIST( list, 2, arg );

    /* make the global variables automatic                                 */
    for ( i = 3; i <= LEN_LIST(args); i++ ) {
        name = ELM_LIST( args, i );
        while ( ! IsStringConv(name) ) {
            name = ErrorReturnObj(
                "AUTO: <name> must be a string (not a %s)",
                (Int)TNAM_OBJ(name), 0L,
                "you can return a string for <name>" );
        }
        gvar = GVarName( CSTR_STRING(name) );
        SET_ELM_PLIST( ValGVars,   gvar, 0    );
        SET_ELM_PLIST( ExprGVars, gvar, list );
        CHANGED_BAG(   ExprGVars );
    }

    /* return void                                                         */
    return 0;
}


/****************************************************************************
**
*F  iscomplete( <name>, <len> ) . . . . . . . .  find the completions of name
*F  completion( <name>, <len> ) . . . . . . . .  find the completions of name
*/
UInt            iscomplete_gvar (
    Char *              name,
    UInt                len )
{
    Char *              curr;
    UInt                i, k;

    for ( i = 1; i <= CountGVars; i++ ) {
        curr = NameGVar( i );
        for ( k = 0; name[k] != 0 && curr[k] == name[k]; k++ ) ;
        if ( k == len && curr[k] == '\0' )  return 1;
    }
    return 0;
}

UInt            completion_gvar (
    Char *              name,
    UInt                len )
{
    Char *              curr;
    Char *              next;
    UInt                i, k;

    next = 0;
    for ( i = 1; i <= CountGVars; i++ ) {
        /* consider only variables which are currently bound for completion */
        if ( VAL_GVAR( i ) || ELM_PLIST( ExprGVars, i )) {
            curr = NameGVar( i );
            for ( k = 0; name[k] != 0 && curr[k] == name[k]; k++ ) ;
            if ( k < len || curr[k] <= name[k] )  continue;
            if ( next != 0 ) {
                for ( k = 0; curr[k] != '\0' && curr[k] == next[k]; k++ ) ;
                if ( k < len || next[k] < curr[k] )  continue;
            }
            next = curr;
        }
    }

    if ( next != 0 ) {
        for ( k = 0; next[k] != '\0'; k++ )
            name[k] = next[k];
        name[k] = '\0';
    }

    return next != 0;
}


/****************************************************************************
**
*F  FuncIDENTS_GVAR( <self> ) . . . . . . . . . .  idents of global variables
*/
Obj FuncIDENTS_GVAR (
    Obj                 self )
{
    /*QQ extern Obj          NameGVars;   */
    Obj                 copy;
    UInt                i;

    copy = NEW_PLIST( T_PLIST+IMMUTABLE, LEN_PLIST(NameGVars) );
    for ( i = 1;  i <= LEN_PLIST(NameGVars);  i++ ) {
        SET_ELM_PLIST( copy, i, ELM_PLIST( NameGVars, i ) );
    }
    SET_LEN_PLIST( copy, LEN_PLIST(NameGVars) );
    return copy;
}

Obj FuncIDENTS_BOUND_GVARS (
    Obj                 self )
{
    /*QQ extern Obj          NameGVars;   */
    Obj                 copy;
    UInt                i, j;

    copy = NEW_PLIST( T_PLIST+IMMUTABLE, LEN_PLIST(NameGVars) );
    for ( i = 1, j = 1;  i <= LEN_PLIST(NameGVars);  i++ ) {
        if ( VAL_GVAR( i ) || ELM_PLIST( ExprGVars, i )) {
           SET_ELM_PLIST( copy, j, ELM_PLIST( NameGVars, i ) );
           j++;
        }
    }
    SET_LEN_PLIST( copy, j - 1 );
    return copy;
}

/****************************************************************************
**
*F  FuncASS_GVAR( <self>, <gvar>, <val> ) . . . . assign to a global variable
*/
Obj FuncASS_GVAR (
    Obj                 self,
    Obj                 gvar,
    Obj                 val )
{
    /* check the argument                                                  */
    while ( ! IsStringConv( gvar ) ) {
        gvar = ErrorReturnObj(
            "READ: <gvar> must be a string (not a %s)",
            (Int)TNAM_OBJ(gvar), 0L,
            "you can return a string for <gvar>" );
    }

    AssGVar( GVarName( CSTR_STRING(gvar) ), val );
    return 0L;
}


/****************************************************************************
**
*F  FuncISB_GVAR( <self>, <gvar> )  . . check assignment of a global variable
*/
Obj FuncISB_GVAR (
    Obj                 self,
    Obj                 gvar )
{
  UInt gv;
    /* check the argument                                                  */
    while ( ! IsStringConv( gvar ) ) {
        gvar = ErrorReturnObj(
            "ISB_GVAR: <gvar> must be a string (not a %s)",
            (Int)TNAM_OBJ(gvar), 0L,
            "you can return a string for <gvar>" );
    }

    gv = GVarName( CSTR_STRING(gvar) );
    return ( VAL_GVAR( gv ) ||
             ELM_PLIST( ExprGVars, gv )) ? True : False;
}


/****************************************************************************
**
*F  FuncVAL_GVAR( <self>, <gvar> )  . . contents of a global variable
*/

Obj FuncVAL_GVAR (
    Obj                 self,
   Obj                 gvar )
{
  Obj val;
    /* check the argument                                                  */
    while ( ! IsStringConv( gvar ) ) {
        gvar = ErrorReturnObj(
            "VAL_GVAR: <gvar> must be a string (not a %s)",
            (Int)TNAM_OBJ(gvar), 0L,
            "you can return a string for <gvar>" );
    }

    /* get the value */
    val = ValAutoGVar( GVarName( CSTR_STRING(gvar) ) );

    while (val == (Obj) 0)
      val = ErrorReturnObj("VAL_GVAR: No value bound to %s",
                           (Int)CSTR_STRING(gvar), (Int) 0,
                           "you can return a value" );
    return val;
}

/****************************************************************************
**
*F  FuncUNB_GVAR( <self>, <gvar> )  . . unbind a global variable
*/

Obj FuncUNB_GVAR (
    Obj                 self,
    Obj                 gvar )
{
    /* check the argument                                                  */
    while ( ! IsStringConv( gvar ) ) {
        gvar = ErrorReturnObj(
            "UNB_GVAR: <gvar> must be a string (not a %s)",
            (Int)TNAM_OBJ(gvar), 0L,
            "you can return a string for <gvar>" );
    }

    /*  */
    AssGVar( GVarName( CSTR_STRING(gvar) ), (Obj)0 );
    return (Obj) 0;
}



/****************************************************************************
**

*F * * * * * * * * * * * * * copies and fopies  * * * * * * * * * * * * * * *
*/


/****************************************************************************
**

*V  CopyAndFopyGVars  . . . . . .  kernel table of kernel copies and "fopies"
**
**  This needs to be kept inside the kernel so that the copies can be updated
**  after loading a workspace.
*/  
typedef struct  { 
    Obj *               copy;
    UInt                isFopy;
    const Char *        name;
} StructCopyGVar;

#ifndef MAX_COPY_AND_FOPY_GVARS
#define MAX_COPY_AND_FOPY_GVARS         30000
#endif

static StructCopyGVar CopyAndFopyGVars[MAX_COPY_AND_FOPY_GVARS];
static Int NCopyAndFopyGVars;


/****************************************************************************
**
*F  InitCopyGVar( <name>, <copy> )  . .  declare C variable as copy of global
**
**  'InitCopyGVar' makes  the C variable <cvar>  at address  <copy> a copy of
**  the global variable named <name> (which must be a kernel string).
**
**  The function only registers the  information in <CopyAndFopyGVars>.  At a
**  latter stage one  has to call  'UpdateCopyFopyInfo' to actually enter the
**  information stored in <CopyAndFopyGVars> into a plain list.
**
**  This is OK for garbage collection, but  a real problem  for saving in any
**  event, this information  does not really want to  be saved  because it is
**  kernel centred rather than workspace centred.
**
**  Accordingly we     provide  two    functions    `RemoveCopyFopyInfo'  and
**  `RestoreCopyFopyInfo' to  remove  or restore   the  information from  the
**  workspace.  The  Restore  function is  also   intended to  be used  after
**  loading a saved workspace
*/
void InitCopyGVar (
    const Char *        name ,
    Obj *               copy )
{
    /* make a record in the kernel for saving and loading                  */
    if ( NCopyAndFopyGVars >= MAX_COPY_AND_FOPY_GVARS ) {
        Pr( "Panic, no room to record CopyGVar\n", 0L, 0L );
        SyExit(1);
    }
    CopyAndFopyGVars[NCopyAndFopyGVars].copy = copy;
    CopyAndFopyGVars[NCopyAndFopyGVars].isFopy = 0;
    CopyAndFopyGVars[NCopyAndFopyGVars].name = name;
    NCopyAndFopyGVars++;
}


/****************************************************************************
**
*F  InitFopyGVar( <name>, <copy> )  . .  declare C variable as copy of global
**
**  'InitFopyGVar' makes the C variable <cvar> at address <copy> a (function)
**  copy  of the  global variable <gvar>,  whose name  is <name>.  That means
**  that whenever   the value  of   <gvar> is a    function, then <cvar> will
**  reference the same value (i.e., will hold the same bag identifier).  When
**  the value  of <gvar>  is not a   function, then  <cvar> will  reference a
**  function  that signals  the error ``<func>  must be  a function''.   When
**  <gvar> has no assigned value, then <cvar> will  reference a function that
**  signals the error ``<gvar> must have an assigned value''.
*/
void InitFopyGVar (
    const Char *        name,
    Obj *               copy )
{
    /* make a record in the kernel for saving and loading                  */
    if ( NCopyAndFopyGVars >= MAX_COPY_AND_FOPY_GVARS ) {
        Pr( "Panic, no room to record FopyGVar\n", 0L, 0L );
        SyExit(1);
    }
    CopyAndFopyGVars[NCopyAndFopyGVars].copy = copy;
    CopyAndFopyGVars[NCopyAndFopyGVars].isFopy = 1;
    CopyAndFopyGVars[NCopyAndFopyGVars].name = name;
    NCopyAndFopyGVars++;
}


/****************************************************************************
**
*F  UpdateCopyFopyInfo()  . . . . . . . . . .  convert kernel info into plist
*/
static Int NCopyAndFopyDone;

void UpdateCopyFopyInfo ( void )
{
    Obj                 cops;           /* copies list                     */
    UInt                ncop;           /* number of copies                */
    UInt                gvar;
    const Char *        name;           /* name of the variable            */
    Obj *               copy;           /* address of the copy             */

    /* loop over new copies and fopies                                     */
    for ( ; NCopyAndFopyDone < NCopyAndFopyGVars; NCopyAndFopyDone++ ) {
        name = CopyAndFopyGVars[NCopyAndFopyDone].name;
        copy = CopyAndFopyGVars[NCopyAndFopyDone].copy;
        gvar = GVarName(name);

        /* get the copies list and its length                              */
        if ( CopyAndFopyGVars[NCopyAndFopyDone].isFopy ) {
            if ( ELM_PLIST( FopiesGVars, gvar ) != 0 ) {
                cops = ELM_PLIST( FopiesGVars, gvar );
            }
            else {
                cops = NEW_PLIST( T_PLIST, 0 );
                SET_ELM_PLIST( FopiesGVars, gvar, cops );
                CHANGED_BAG(FopiesGVars);
            }
        }
        else {
            if ( ELM_PLIST( CopiesGVars, gvar ) != 0 ) {
                cops = ELM_PLIST( CopiesGVars, gvar );
            }
            else {
                cops = NEW_PLIST( T_PLIST, 0 );
                SET_ELM_PLIST( CopiesGVars, gvar, cops );
                CHANGED_BAG(CopiesGVars);
            }
        }
        ncop = LEN_PLIST(cops);

        /* append the copy to the copies list                              */
        GROW_PLIST( cops, ncop+1 );
        SET_LEN_PLIST( cops, ncop+1 );
        SET_ELM_PLIST( cops, ncop+1, (Obj)copy );
        CHANGED_BAG(cops);

        /* now copy the value of <gvar> to <cvar>                          */
        if ( CopyAndFopyGVars[NCopyAndFopyDone].isFopy ) {
            if ( VAL_GVAR(gvar) != 0 && IS_FUNC(VAL_GVAR(gvar)) ) {
                *copy = VAL_GVAR(gvar);
            }
            else if ( VAL_GVAR(gvar) != 0 ) {
                *copy = ErrorMustEvalToFuncFunc;
            }
            else {
                *copy = ErrorMustHaveAssObjFunc;
            }
        }
        else {
            *copy = VAL_GVAR(gvar);
        }
    }
}


/****************************************************************************
**
*F  RemoveCopyFopyInfo()  . . . remove the info about copies of gvars from ws
*/
void RemoveCopyFopyInfo( void )
{
    UInt        i, l;

    l = LEN_PLIST(CopiesGVars);
    for ( i = 1; i <= l; i++ )
        SET_ELM_PLIST( CopiesGVars, i, 0 );
    l = LEN_PLIST(FopiesGVars);
    for ( i = 1; i <= l; i++ )
        SET_ELM_PLIST( FopiesGVars, i, 0 );
    NCopyAndFopyDone = 0;
    return;
}


/****************************************************************************
**
*F  RestoreCopyFopyInfo() . . .  restore the info from the copy in the kernel
*/
void RestoreCopyFopyInfo( void )
{
    NCopyAndFopyDone = 0;
    UpdateCopyFopyInfo();
}


/****************************************************************************
**

*F * * * * * * * * * * * * * initialize package * * * * * * * * * * * * * * *
*/


/****************************************************************************
**

*V  GVarFuncs . . . . . . . . . . . . . . . . . . list of functions to export
*/
static StructGVarFunc GVarFuncs [] = {

    { "MakeReadOnlyGVar", 1, "name",
      MakeReadOnlyGVarHandler, "src/gap.c:MakeReadOnlyGVar" },

    { "MakeReadWriteGVar", 1, "name",
      MakeReadWriteGVarHandler, "src/gap.c:MakeReadWriteGVar" },

    { "IsReadOnlyGVar", 1, "name",
      FuncIsReadOnlyGVar, "src/gap.c:IsReadOnlyGVar" },

    { "AUTO", -1, "args",
      AUTOHandler, "src/gap.c:AUTO" },
               
    { "IDENTS_GVAR", 0L, "",
      FuncIDENTS_GVAR, "src/gap.c:IDENTS_GVAR" },

    { "IDENTS_BOUND_GVARS", 0L, "",
      FuncIDENTS_BOUND_GVARS, "src/gap.c:IDENTS_BOUND_GVARS" },

    { "ISB_GVAR", 1L, "gvar",
      FuncISB_GVAR, "src/gap.c:ISB_GVAR" },

    { "ASS_GVAR", 2L, "gvar, value",
      FuncASS_GVAR, "src/gap.c:ASS_GVAR" },

    { "VAL_GVAR", 1L, "gvar",
      FuncVAL_GVAR, "src/gap.c:VAL_GVAR" },

    { "UNB_GVAR", 1L, "gvar",
      FuncUNB_GVAR, "src/gap.c:UNB_GVAR" },

    { "SET_NAMESPACE", 1L, "str",
      FuncSET_NAMESPACE, "src/gvars.c:SET_NAMESPACE" },

    { "GET_NAMESPACE", 0L, "",
      FuncGET_NAMESPACE, "src/gvars.c:GET_NAMESPACE" },

    { 0 }

};


/****************************************************************************
**

*F  InitKernel( <module> )  . . . . . . . . initialise kernel data structures
*/
static Int InitKernel (
    StructInitInfo *    module )
{
  ValGVars = (Obj) 0;
  NCopyAndFopyGVars = 0;
  NCopyAndFopyDone = 0;
  InitHandlerRegistration();
  
    /* init global bags and handler                                        */
    InitGlobalBag( &ErrorMustEvalToFuncFunc,
                   "src/gvars.c:ErrorMustEvalToFuncFunc" );
    InitGlobalBag( &ErrorMustHaveAssObjFunc,
                   "src/gvars.c:ErrorMustHaveAssObjFunc" );
    InitGlobalBag( &ValGVars,
                   "src/gvars.c:ValGVars" );
    InitGlobalBag( &NameGVars,
                   "src/gvars.c:NameGVars" );
    InitGlobalBag( &WriteGVars,
                   "src/gvars.c:WriteGVars" );
    InitGlobalBag( &ExprGVars,
                   "src/gvars.c:ExprGVars" );
    InitGlobalBag( &CopiesGVars,
                   "src/gvars.c:CopiesGVars" );
    InitGlobalBag( &FopiesGVars,
                   "src/gvars.c:FopiesGVars"  );
    InitGlobalBag( &TableGVars,
                   "src/gvars.c:TableGVars" );
    InitGlobalBag( &CurrNamespace,
                   "src/gvars.c:CurrNamespace" );

    InitHandlerFunc( ErrorMustEvalToFuncHandler,
                     "src/gvars.c:ErrorMustEvalToFuncHandler" );
    InitHandlerFunc( ErrorMustHaveAssObjHandler,
                     "src/gvars.c:ErrorMustHaveAssObjHandler" );

    /* init filters and functions                                          */
    InitHdlrFuncsFromTable( GVarFuncs );

    /* Get a copy of REREADING                                             */
    ImportGVarFromLibrary("REREADING", &REREADING);
    
    
    /* return success                                                      */
    return 0;
}


/****************************************************************************
**
*F  PostRestore( <module> ) . . . . . . . . . . . . . after restore workspace
*/

static Int PostRestore (
    StructInitInfo *    module )
{
    /* make the lists for global variables                                 */
    CountGVars = LEN_PLIST( ValGVars );
    PtrGVars   = ADDR_OBJ( ValGVars );
    SizeGVars  = LEN_PLIST( TableGVars );

    /* create the global variable '~'                                      */
    Tilde = GVarName( "~" );


    /* update fopies and copies                                            */
    UpdateCopyFopyInfo();

    /* return success                                                      */
    return 0;
}

/****************************************************************************
**
*F  PreSave( <module> ) . . . . . . . . . . . . . before save workspace
*/
static Int PreSave (
    StructInitInfo *    module )
{
  RemoveCopyFopyInfo();
  return 0;
}

/****************************************************************************
**
*F  PostSave( <module> ) . . . . . . . . . . . . . aftersave workspace
*/
static Int PostSave (
    StructInitInfo *    module )
{
  UpdateCopyFopyInfo();
  return 0;
}


/****************************************************************************
**
*F  InitLibrary( <module> ) . . . . . . .  initialise library data structures
*/
static Int InitLibrary (
    StructInitInfo *    module )
{
    /* make the error functions for 'AssGVar'                              */
    ErrorMustEvalToFuncFunc = NewFunctionC(
        "ErrorMustEvalToFunc", -1,"args", ErrorMustEvalToFuncHandler );
    
    ErrorMustHaveAssObjFunc = NewFunctionC(
        "ErrorMustHaveAssObj", -1L,"args", ErrorMustHaveAssObjHandler );

    /* make the lists for global variables                                 */
    ValGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( ValGVars, 0 );

    NameGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( NameGVars, 0 );

    WriteGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( WriteGVars, 0 );

    ExprGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( ExprGVars, 0 );

    CopiesGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( CopiesGVars, 0 );

    FopiesGVars = NEW_PLIST( T_PLIST, 0 );
    SET_LEN_PLIST( FopiesGVars, 0 );

    /* make the list of global variables                                   */
    SizeGVars  = 997;
    TableGVars = NEW_PLIST( T_PLIST, SizeGVars );
    SET_LEN_PLIST( TableGVars, SizeGVars );

    /* Create the current namespace: */
    TLS(CurrNamespace) = NEW_STRING(0);
    SET_LEN_STRING(TLS(CurrNamespace),0);
    
    /* fix C vars                                                          */
    PostRestore( module );

    /* init filters and functions                                          */
    InitGVarFuncsFromTable( GVarFuncs );

    /* return success                                                      */
    return 0;
}


/****************************************************************************
**
*F  CheckInit( <module> ) . . . . . . . . . . . . . . .  check initialisation
*/
static Int CheckInit (
    StructInitInfo *    module )
{
    Int                 success = 1;

    if ( NCopyAndFopyGVars != NCopyAndFopyDone ) {
        success = 0;
        Pr( "#W  failed to updated copies and fopies\n", 0L, 0L );
    }

    /* return success                                                      */
    return ! success;
}


/****************************************************************************
**
*F  InitInfoGVars() . . . . . . . . . . . . . . . . . table of init functions
*/
static StructInitInfo module = {
    MODULE_BUILTIN,                     /* type                           */
    "gvars",                            /* name                           */
    0,                                  /* revision entry of c file       */
    0,                                  /* revision entry of h file       */
    0,                                  /* version                        */
    0,                                  /* crc                            */
    InitKernel,                         /* initKernel                     */
    InitLibrary,                        /* initLibrary                    */
    CheckInit,                          /* checkInit                      */
    PreSave,                            /* preSave                        */
    PostSave,                            /* postSave                       */
    PostRestore                         /* postRestore                    */
};

StructInitInfo * InitInfoGVars ( void )
{
    return &module;
}


/****************************************************************************
**

*E  gvars.c . . . . . . . . . . . . . . . . . . . . . . . . . . . . ends here
*/