tests/glr-regression.at

   1 # Checking GLR Parsing: Regression Tests           -*- Autotest -*-
   2 # Copyright (C) 2002, 2003, 2005, 2006 Free Software Foundation, Inc.
   3
   4 # This program is free software; you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation; either version 2, or (at your option)
   7 # any later version.
   8
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program; if not, write to the Free Software
  16 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17 # 02110-1301, USA.
  18
  19 AT_BANNER([[GLR Regression Tests]])
  20
  21 ## --------------------------- ##
  22 ## Badly Collapsed GLR States. ##
  23 ## --------------------------- ##
  24
  25 AT_SETUP([Badly Collapsed GLR States])
  26
  27 AT_DATA_GRAMMAR([glr-regr1.y],
  28 [[/* Regression Test: Improper state compression */
  29 /* Reported by Scott McPeak */
  30
  31 %{
  32 #include <stdio.h>
  33
  34 #define YYSTYPE int
  35 static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
  36 int yylex (void);
  37 void yyerror (char const *msg);
  38 %}
  39
  40
  41 %glr-parser
  42
  43
  44 /* -------- productions ------ */
  45 %%
  46
  47 StartSymbol: E  { $$=0; }                   %merge <exprMerge>
  48            ;
  49
  50 E: E 'P' E { $$=1; printf("E -> E 'P' E\n"); }  %merge <exprMerge>
  51  | 'B'     { $$=2; printf("E -> 'B'\n"); }      %merge <exprMerge>
  52  ;
  53
  54
  55
  56 /* ---------- C code ----------- */
  57 %%
  58
  59 static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1)
  60 {
  61   (void) x0;
  62   (void) x1;
  63   printf ("<OR>\n");
  64   return 0;
  65 }
  66
  67 int
  68 main (void)
  69 {
  70   return yyparse ();
  71 }
  72
  73 void
  74 yyerror (char const *msg)
  75 {
  76   fprintf (stderr, "%s\n", msg);
  77 }
  78
  79
  80 int
  81 yylex (void)
  82 {
  83   for (;;)
  84     {
  85       int ch = getchar ();
  86       if (ch == EOF)
  87         return 0;
  88       else if (ch == 'B' || ch == 'P')
  89         return ch;
  90     }
  91 }
  92 ]])
  93
  94 AT_CHECK([[bison -o glr-regr1.c glr-regr1.y]], 0, [],
  95 [glr-regr1.y: conflicts: 1 shift/reduce
  96 ])
  97 AT_COMPILE([glr-regr1])
  98 AT_CHECK([[echo BPBPB | ./glr-regr1]], 0,
  99 [[E -> 'B'
 100 E -> 'B'
 101 E -> E 'P' E
 102 E -> 'B'
 103 E -> E 'P' E
 104 E -> 'B'
 105 E -> E 'P' E
 106 E -> E 'P' E
 107 <OR>
 108 ]], [])
 109
 110 AT_CLEANUP
 111
 112 ## ------------------------------------------------------------ ##
 113 ## Improper handling of embedded actions and $-N in GLR parsers ##
 114 ## ------------------------------------------------------------ ##
 115
 116 AT_SETUP([Improper handling of embedded actions and dollar(-N) in GLR parsers])
 117
 118 AT_DATA_GRAMMAR([glr-regr2a.y],
 119 [[/* Regression Test: Improper handling of embedded actions and $-N  */
 120 /* Reported by S. Eken */
 121
 122 %{
 123   #define YYSTYPE char *
 124
 125   #include <ctype.h>
 126   #include <stdio.h>
 127   #include <stdlib.h>
 128   #include <string.h>
 129   int yylex (void);
 130   void yyerror (char const *);
 131 %}
 132
 133 %glr-parser
 134
 135 %%
 136
 137 command:
 138     's' var 't'
 139        { printf ("Variable: '%s'\n", $2); }
 140     'v' 'x' 'q'
 141        { free ($2); }
 142   | 's' var_list 't' 'e'
 143        { printf ("Varlist: '%s'\n", $2); free ($2); }
 144   | 's' var 't' var_printer 'x'
 145        { free ($2); }
 146   ;
 147
 148 var:
 149   'V'
 150      { $$ = $1; }
 151   ;
 152
 153 var_list:
 154   var
 155     { $$ = $1; }
 156   | var ',' var_list
 157     {
 158       char *s = (char *) realloc ($1, strlen ($1) + 1 + strlen ($3) + 1);
 159       strcat (s, ",");
 160       strcat (s, $3);
 161       free ($3);
 162       $$ = s;
 163     }
 164   ;
 165
 166 var_printer: 'v'
 167    { printf ("Variable: '%s'\n", $-1); }
 168
 169 %%
 170
 171 FILE *input = NULL;
 172
 173 int
 174 yylex (void)
 175 {
 176   char buf[50];
 177   char *s;
 178   switch (fscanf (input, " %1[a-z,]", buf)) {
 179   case 1:
 180     return buf[0];
 181   case EOF:
 182     return 0;
 183   default:
 184     break;
 185   }
 186   if (fscanf (input, "%49s", buf) != 1)
 187     return 0;
 188   if (sizeof buf - 1 <= strlen (buf))
 189     abort ();
 190   s = (char *) malloc (strlen (buf) + 1);
 191   strcpy (s, buf);
 192   yylval = s;
 193   return 'V';
 194 }
 195
 196 void
 197 yyerror (char const *s)
 198 { printf ("%s\n", s);
 199 }
 200
 201 int
 202 main (int argc, char **argv)
 203 {
 204   input = stdin;
 205   if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
 206   return yyparse ();
 207 }
 208 ]])
 209
 210 AT_CHECK([[bison -o glr-regr2a.c glr-regr2a.y]], 0, [],
 211 [glr-regr2a.y: conflicts: 2 shift/reduce
 212 ])
 213 AT_COMPILE([glr-regr2a])
 214
 215 AT_CHECK([[echo s VARIABLE_1 t v x q | ./glr-regr2a]], 0,
 216 [[Variable: 'VARIABLE_1'
 217 ]], [])
 218 AT_CHECK([[echo s VARIABLE_1 , ANOTHER_VARIABLE_2 t e | ./glr-regr2a]], 0,
 219 [[Varlist: 'VARIABLE_1,ANOTHER_VARIABLE_2'
 220 ]])
 221 AT_CHECK([[echo s VARIABLE_3 t v x | ./glr-regr2a]], 0,
 222 [[Variable: 'VARIABLE_3'
 223 ]], [])
 224
 225
 226 AT_CLEANUP
 227
 228 ## ------------------------------------------------------------ ##
 229 ## Improper merging of GLR delayed action sets                  ##
 230 ## ------------------------------------------------------------ ##
 231
 232 AT_SETUP([Improper merging of GLR delayed action sets])
 233
 234 AT_DATA_GRAMMAR([glr-regr3.y],
 235 [[/* Regression Test: Improper merging of GLR delayed action sets.  */
 236 /* Reported by M. Rosien */
 237
 238 %{
 239 #include <stdio.h>
 240 #include <stdarg.h>
 241
 242 static int MergeRule (int x0, int x1);
 243 static void yyerror (char const * s);
 244 int yylex (void);
 245
 246 #define RULE(x) (1 << (x))
 247
 248 %}
 249
 250 %glr-parser
 251
 252 %token BAD_CHAR
 253 %token P1 P2 T1 T2 T3 T4 O1 O2
 254
 255 %%
 256
 257 S : P1 T4 O2 NT6 P2  { printf ("Result: %x\n", $4); }
 258 ;
 259
 260 NT1 : P1 T1 O1 T2 P2 { $$ = RULE(2); }  %merge<MergeRule>
 261 ;
 262
 263 NT2 : NT1             { $$ = RULE(3); } %merge<MergeRule>
 264     | P1 NT1 O1 T3 P2 { $$ = RULE(4); } %merge<MergeRule>
 265 ;
 266
 267 NT3 : T3              { $$ = RULE(5); } %merge<MergeRule>
 268     | P1 NT1 O1 T3 P2 { $$ = RULE(6); } %merge<MergeRule>
 269 ;
 270
 271 NT4 : NT3              { $$ = RULE(7); } %merge<MergeRule>
 272     | NT2              { $$ = RULE(8); } %merge<MergeRule>
 273     | P1 NT2 O1 NT3 P2 { $$ = RULE(9); } %merge<MergeRule>
 274 ;
 275
 276 NT5 : NT4              { $$ = RULE(10); } %merge<MergeRule>
 277 ;
 278
 279 NT6 : P1 NT1 O1 T3 P2  { $$ = RULE(11) | $2; } %merge<MergeRule>
 280     | NT5              { $$ = RULE(12) | $1; } %merge<MergeRule>
 281 ;
 282
 283 %%
 284
 285 static int MergeRule (int x0, int x1) {
 286   return x0 | x1;
 287 }
 288
 289 static void yyerror(char const * s) {
 290   fprintf(stderr,"error: %s\n",s);
 291 }
 292
 293 FILE *input = NULL;
 294
 295 int P[] = { P1, P2 };
 296 int O[] = { O1, O2 };
 297 int T[] = { T1, T2, T3, T4 };
 298
 299 int yylex (void)
 300 {
 301   char inp[3];
 302   if (fscanf (input, "%2s", inp) == EOF)
 303     return 0;
 304   switch (inp[0])
 305     {
 306     case 'p': return P[inp[1] - '1'];
 307     case 't': return T[inp[1] - '1'];
 308     case 'o': return O[inp[1] - '1'];
 309     }
 310   return BAD_CHAR;
 311 }
 312
 313 int main(int argc, char* argv[]) {
 314   input = stdin;
 315   if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
 316   return yyparse ();
 317 }
 318 ]])
 319
 320 AT_CHECK([[bison -o glr-regr3.c glr-regr3.y]], 0, [],
 321 [glr-regr3.y: conflicts: 1 shift/reduce, 1 reduce/reduce
 322 ])
 323 AT_COMPILE([glr-regr3])
 324
 325 AT_CHECK([[echo p1 t4 o2 p1 p1 t1 o1 t2 p2 o1 t3 p2 p2 | ./glr-regr3]], 0,
 326 [[Result: 1c04
 327 ]], [])
 328
 329 AT_CLEANUP
 330
 331
 332 ## ------------------------------------------------------------------------- ##
 333 ## Duplicate representation of merged trees.  See                            ##
 334 ## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00013.html>.     ##
 335 ## ------------------------------------------------------------------------- ##
 336
 337 AT_SETUP([Duplicate representation of merged trees])
 338
 339 AT_DATA_GRAMMAR([glr-regr4.y],
 340 [[
 341 %union { char *ptr; }
 342 %type <ptr> S A A1 A2 B
 343 %glr-parser
 344
 345 %{
 346   #include <stdio.h>
 347   #include <stdlib.h>
 348   #include <string.h>
 349   static char *merge (YYSTYPE, YYSTYPE);
 350   static char *make_value (char const *, char const *);
 351   static void yyerror (char const *);
 352   static int yylex (void);
 353 %}
 354
 355 %%
 356
 357 tree: S { printf ("%s\n", $1); } ;
 358
 359 S:
 360   A   %merge<merge> { $$ = make_value ("S", $1); }
 361   | B %merge<merge> { $$ = make_value ("S", $1); }
 362   ;
 363
 364 A:
 365   A1   %merge<merge> { $$ = make_value ("A", $1); }
 366   | A2 %merge<merge> { $$ = make_value ("A", $1); }
 367   ;
 368
 369 A1: 'a' { $$ = make_value ("A1", "'a'"); } ;
 370 A2: 'a' { $$ = make_value ("A2", "'a'"); } ;
 371 B:  'a' { $$ = make_value ("B", "'a'");  } ;
 372
 373 %%
 374
 375 static int
 376 yylex (void)
 377 {
 378   static char const *input = "a";
 379   return *input++;
 380 }
 381
 382 int
 383 main (void)
 384 {
 385   return yyparse ();
 386 }
 387
 388 static char *
 389 make_value (char const *parent, char const *child)
 390 {
 391   char const format[] = "%s <- %s";
 392   char *value =
 393     (char *) malloc (strlen (parent) + strlen (child) + sizeof format);
 394   sprintf (value, format, parent, child);
 395   return value;
 396 }
 397
 398 static char *
 399 merge (YYSTYPE s1, YYSTYPE s2)
 400 {
 401   char const format[] = "merge{ %s and %s }";
 402   char *value =
 403     (char *) malloc (strlen (s1.ptr) + strlen (s2.ptr) + sizeof format);
 404   sprintf (value, format, s1.ptr, s2.ptr);
 405   return value;
 406 }
 407
 408 static void
 409 yyerror (char const *msg)
 410 {
 411   fprintf (stderr, "%s\n", msg);
 412 }
 413 ]])
 414
 415 AT_CHECK([[bison -o glr-regr4.c glr-regr4.y]], 0, [],
 416 [glr-regr4.y: conflicts: 1 reduce/reduce
 417 ])
 418 AT_COMPILE([glr-regr4])
 419
 420 AT_CHECK([[./glr-regr4]], 0,
 421 [[merge{ S <- merge{ A <- A1 <- 'a' and A <- A2 <- 'a' } and S <- B <- 'a' }
 422 ]], [])
 423
 424 AT_CLEANUP
 425
 426
 427 ## -------------------------------------------------------------------------- ##
 428 ## User destructor for unresolved GLR semantic value.  See                    ##
 429 ## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00016.html>.   ##
 430 ## -------------------------------------------------------------------------- ##
 431
 432 AT_SETUP([User destructor for unresolved GLR semantic value])
 433
 434 AT_DATA_GRAMMAR([glr-regr5.y],
 435 [[
 436 %{
 437   #include <stdio.h>
 438   #include <stdlib.h>
 439   static void yyerror (char const *);
 440   static int yylex (void);
 441   enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */
 442 %}
 443
 444 %glr-parser
 445 %union { int value; }
 446 %type <value> start
 447
 448 %destructor {
 449   if ($$ != MAGIC_VALUE)
 450     {
 451       fprintf (stderr, "Bad destructor call.\n");
 452       exit (EXIT_FAILURE);
 453     }
 454 } start
 455
 456 %%
 457
 458 start:
 459    'a' { $$ = MAGIC_VALUE; }
 460    | 'a' { $$ = MAGIC_VALUE; }
 461    ;
 462
 463 %%
 464
 465 static int
 466 yylex (void)
 467 {
 468   static char const *input = "a";
 469   return *input++;
 470 }
 471
 472 static void
 473 yyerror (char const *msg)
 474 {
 475   fprintf (stderr, "%s\n", msg);
 476 }
 477
 478 int
 479 main (void)
 480 {
 481   return yyparse () != 1;
 482 }
 483 ]])
 484
 485 AT_CHECK([[bison -o glr-regr5.c glr-regr5.y]], 0, [],
 486 [glr-regr5.y: conflicts: 1 reduce/reduce
 487 ])
 488 AT_COMPILE([glr-regr5])
 489
 490 AT_CHECK([[./glr-regr5]], 0, [],
 491 [syntax is ambiguous
 492 ])
 493
 494 AT_CLEANUP
 495
 496
 497 ## -------------------------------------------------------------------------- ##
 498 ## User destructor after an error during a split parse.  See                  ##
 499 ## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00029.html>.   ##
 500 ## -------------------------------------------------------------------------- ##
 501
 502 AT_SETUP([User destructor after an error during a split parse])
 503
 504 AT_DATA_GRAMMAR([glr-regr6.y],
 505 [[
 506 %{
 507   #include <stdio.h>
 508   #include <stdlib.h>
 509   static void yyerror (char const *);
 510   static int yylex (void);
 511 %}
 512
 513 %glr-parser
 514 %union { int value; }
 515 %type <value> 'a'
 516
 517 %destructor {
 518   printf ("Destructor called.\n");
 519 } 'a'
 520
 521 %%
 522
 523 start: 'a' | 'a' ;
 524
 525 %%
 526
 527 static int
 528 yylex (void)
 529 {
 530   static char const *input = "a";
 531   return *input++;
 532 }
 533
 534 static void
 535 yyerror (char const *msg)
 536 {
 537   fprintf (stderr, "%s\n", msg);
 538 }
 539
 540 int
 541 main (void)
 542 {
 543   return yyparse () != 1;
 544 }
 545 ]])
 546
 547 AT_CHECK([[bison -o glr-regr6.c glr-regr6.y]], 0, [],
 548 [glr-regr6.y: conflicts: 1 reduce/reduce
 549 ])
 550 AT_COMPILE([glr-regr6])
 551
 552 AT_CHECK([[./glr-regr6]], 0,
 553 [Destructor called.
 554 ],
 555 [syntax is ambiguous
 556 ])
 557
 558 AT_CLEANUP
 559
 560
 561 ## ------------------------------------------------------------------------- ##
 562 ## Duplicated user destructor for lookahead.  See                            ##
 563 ## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00035.html>.  ##
 564 ## ------------------------------------------------------------------------- ##
 565
 566 AT_SETUP([Duplicated user destructor for lookahead])
 567
 568 AT_DATA_GRAMMAR([glr-regr7.y],
 569 [[
 570 %{
 571   #include <stdio.h>
 572   #include <stdlib.h>
 573   static void yyerror (char const *);
 574   static int yylex (void);
 575   #define YYSTACKEXPANDABLE 0
 576 %}
 577
 578 %glr-parser
 579 %union { int *count; }
 580 %type <count> 'a'
 581
 582 %destructor {
 583   if ((*$$)++)
 584     fprintf (stderr, "Destructor called on same value twice.\n");
 585 } 'a'
 586
 587 %%
 588
 589 start:
 590     stack1 start
 591   | stack2 start
 592   | /* empty */
 593   ;
 594 stack1: 'a' ;
 595 stack2: 'a' ;
 596
 597 %%
 598
 599 static int
 600 yylex (void)
 601 {
 602   yylval.count = (int *) malloc (sizeof (int));
 603   if (!yylval.count)
 604     {
 605       fprintf (stderr, "Test inconclusive.\n");
 606       exit (EXIT_FAILURE);
 607     }
 608   *yylval.count = 0;
 609   return 'a';
 610 }
 611
 612 static void
 613 yyerror (char const *msg)
 614 {
 615   fprintf (stderr, "%s\n", msg);
 616 }
 617
 618 int
 619 main (void)
 620 {
 621   return yyparse ();
 622 }
 623 ]])
 624
 625 AT_CHECK([[bison -o glr-regr7.c glr-regr7.y]], 0, [],
 626 [glr-regr7.y: conflicts: 2 reduce/reduce
 627 ])
 628 AT_COMPILE([glr-regr7])
 629
 630 AT_CHECK([[./glr-regr7]], 2, [],
 631 [memory exhausted
 632 ])
 633
 634 AT_CLEANUP
 635
 636
 637 ## ------------------------------------------------------------------------- ##
 638 ## Incorrect default location for empty right-hand sides.  Adapted from bug  ##
 639 ## report by Claudia Hermann.                                                ##
 640 ## See http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00069.html and ##
 641 ## http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00072.html         ##
 642 ## ------------------------------------------------------------------------- ##
 643
 644 AT_SETUP([Incorrectly initialized location for empty right-hand side in GLR])
 645
 646 AT_DATA_GRAMMAR([glr-regr8.y],
 647 [[
 648 %{
 649   #include <stdio.h>
 650   #include <stdlib.h>
 651   static void yyerror (char const *);
 652   static int yylex (void);
 653   static void yyerror (char const *msg);
 654 %}
 655
 656 %token T_CONSTANT
 657 %token T_PORT
 658 %token T_SIGNAL
 659
 660 %glr-parser
 661
 662 %%
 663
 664
 665 PortClause      : T_PORT InterfaceDeclaration T_PORT
 666                 { printf("%d/%d - %d/%d - %d/%d\n",
 667                          @1.first_column, @1.last_column,
 668                          @2.first_column, @2.last_column,
 669                          @3.first_column, @3.last_column); }
 670         ;
 671
 672 InterfaceDeclaration    : OptConstantWord       %dprec 1
 673         | OptSignalWord %dprec 2
 674         ;
 675
 676 OptConstantWord : /* empty */
 677         | T_CONSTANT
 678         ;
 679
 680 OptSignalWord   : /* empty */
 681                 { printf("empty: %d/%d\n", @$.first_column, @$.last_column); }
 682         | T_SIGNAL
 683         ;
 684
 685 %%
 686
 687 void
 688 yyerror (char const *msg)
 689 {
 690   fprintf (stderr, "%s\n", msg);
 691 }
 692
 693 static int lexIndex;
 694
 695 int yylex (void)
 696 {
 697   lexIndex += 1;
 698   switch (lexIndex)
 699     {
 700     case 1:
 701       yylloc.first_column = 1;
 702       yylloc.last_column = 9;
 703       return T_PORT;
 704     case 2:
 705       yylloc.first_column = 13;
 706       yylloc.last_column = 17;
 707       return T_PORT;
 708     default:
 709       return 0;
 710     }
 711 }
 712
 713 int
 714 main (void)
 715 {
 716   yyparse();
 717   return 0;
 718 }
 719 ]])
 720
 721 AT_CHECK([[bison -o glr-regr8.c glr-regr8.y]], 0, [],
 722 [glr-regr8.y: conflicts: 1 reduce/reduce
 723 ])
 724 AT_COMPILE([glr-regr8])
 725
 726 AT_CHECK([[./glr-regr8]], 0,
 727 [empty: 9/9
 728 1/9 - 9/9 - 13/17
 729 ],
 730 [])
 731
 732 AT_CLEANUP
 733
 734
 735 ## ------------------------------------------------------------------------- ##
 736 ## No users destructors if stack 0 deleted.  See                             ##
 737 ## <http://lists.gnu.org/archive/html/bison-patches/2005-09/msg00109.html>.  ##
 738 ## ------------------------------------------------------------------------- ##
 739
 740 AT_SETUP([No users destructors if stack 0 deleted])
 741
 742 AT_DATA_GRAMMAR([glr-regr9.y],
 743 [[
 744 %{
 745 # include <stdio.h>
 746 # include <stdlib.h>
 747   static void yyerror (char const *);
 748   static int yylex (void);
 749 # define YYSTACKEXPANDABLE 0
 750   static int tokens = 0;
 751   static int destructors = 0;
 752 # define USE(Var)
 753 %}
 754
 755 %glr-parser
 756 %union { int dummy; }
 757 %type <dummy> 'a'
 758
 759 %destructor {
 760   destructors += 1;
 761 } 'a'
 762
 763 %%
 764
 765 start:
 766     ambig0 'a'   { destructors += 2; USE ($2); }
 767   | ambig1 start { destructors += 1; }
 768   | ambig2 start { destructors += 1; }
 769   ;
 770
 771 ambig0: 'a' ;
 772 ambig1: 'a' ;
 773 ambig2: 'a' ;
 774
 775 %%
 776
 777 static int
 778 yylex (void)
 779 {
 780   tokens += 1;
 781   return 'a';
 782 }
 783
 784 static void
 785 yyerror (char const *msg)
 786 {
 787   fprintf (stderr, "%s\n", msg);
 788 }
 789
 790 int
 791 main (void)
 792 {
 793   int exit_status;
 794   exit_status = yyparse ();
 795   if (tokens != destructors)
 796     {
 797       fprintf (stderr, "Tokens = %d, Destructors = %d\n", tokens, destructors);
 798       return 1;
 799     }
 800   return !exit_status;
 801 }
 802 ]])
 803
 804 AT_CHECK([[bison -o glr-regr9.c glr-regr9.y]], 0, [],
 805 [glr-regr9.y: conflicts: 1 reduce/reduce
 806 ])
 807 AT_COMPILE([glr-regr9])
 808
 809 AT_CHECK([[./glr-regr9]], 0, [],
 810 [memory exhausted
 811 ])
 812
 813 AT_CLEANUP
 814
 815
 816 ## ------------------------------------------------------------------------- ##
 817 ## Corrupted semantic options if user action cuts parse.                     ##
 818 ## ------------------------------------------------------------------------- ##
 819
 820 AT_SETUP([Corrupted semantic options if user action cuts parse])
 821
 822 AT_DATA_GRAMMAR([glr-regr10.y],
 823 [[
 824 %{
 825 # include <stdio.h>
 826   static void yyerror (char const *);
 827   static int yylex (void);
 828   #define GARBAGE_SIZE 50
 829   static char garbage[GARBAGE_SIZE];
 830 %}
 831
 832 %glr-parser
 833 %union { char *ptr; }
 834 %type <ptr> start
 835
 836 %%
 837
 838 start:
 839     %dprec 2 { $$ = garbage; YYACCEPT; }
 840   | %dprec 1 { $$ = garbage; YYACCEPT; }
 841   ;
 842
 843 %%
 844
 845 static void
 846 yyerror (char const *msg)
 847 {
 848   fprintf (stderr, "%s\n", msg);
 849 }
 850
 851 static int
 852 yylex (void)
 853 {
 854   return 0;
 855 }
 856
 857 int
 858 main (void)
 859 {
 860   int i;
 861   for (i = 0; i < GARBAGE_SIZE; i+=1)
 862     garbage[i] = 108;
 863   return yyparse ();
 864 }
 865 ]])
 866
 867 AT_CHECK([[bison -o glr-regr10.c glr-regr10.y]], 0, [],
 868 [glr-regr10.y: conflicts: 1 reduce/reduce
 869 ])
 870 AT_COMPILE([glr-regr10])
 871
 872 AT_CHECK([[./glr-regr10]], 0, [], [])
 873
 874 AT_CLEANUP
 875
 876
 877 ## ------------------------------------------------------------------------- ##
 878 ## Undesirable destructors if user action cuts parse.                        ##
 879 ## ------------------------------------------------------------------------- ##
 880
 881 AT_SETUP([Undesirable destructors if user action cuts parse])
 882
 883 AT_DATA_GRAMMAR([glr-regr11.y],
 884 [[
 885 %{
 886 # include <stdlib.h>
 887   static void yyerror (char const *);
 888   static int yylex (void);
 889   static int destructors = 0;
 890 # define USE(val)
 891 %}
 892
 893 %glr-parser
 894 %union { int dummy; }
 895 %type <int> 'a'
 896 %destructor { destructors += 1; } 'a'
 897
 898 %%
 899
 900 start:
 901     'a' %dprec 2 { USE ($1); destructors += 1; YYACCEPT; }
 902   | 'a' %dprec 1 { USE ($1); destructors += 1; YYACCEPT; }
 903   ;
 904
 905 %%
 906
 907 static void
 908 yyerror (char const *msg)
 909 {
 910   fprintf (stderr, "%s\n", msg);
 911 }
 912
 913 static int
 914 yylex (void)
 915 {
 916   static char const *input = "a";
 917   return *input++;
 918 }
 919
 920 int
 921 main (void)
 922 {
 923   int exit_status = yyparse ();
 924   if (destructors != 1)
 925     {
 926       fprintf (stderr, "Destructor calls: %d\n", destructors);
 927       return 1;
 928     }
 929   return exit_status;
 930 }
 931 ]])
 932
 933 AT_CHECK([[bison -o glr-regr11.c glr-regr11.y]], 0, [],
 934 [glr-regr11.y: conflicts: 1 reduce/reduce
 935 ])
 936 AT_COMPILE([glr-regr11])
 937
 938 AT_CHECK([[./glr-regr11]], 0, [], [])
 939
 940 AT_CLEANUP
 941
 942
 943 ## ------------------------------------------------------------------------- ##
 944 ## Leaked semantic values if user action cuts parse.                         ##
 945 ## ------------------------------------------------------------------------- ##
 946
 947 AT_SETUP([Leaked semantic values if user action cuts parse])
 948
 949 AT_DATA_GRAMMAR([glr-regr12.y],
 950 [[
 951 %glr-parser
 952 %union { int dummy; }
 953 %token PARENT_RHS_AFTER
 954 %type <dummy> parent_rhs_before merged PARENT_RHS_AFTER
 955 %destructor { parent_rhs_before_value = 0; } parent_rhs_before
 956 %destructor { merged_value = 0; } merged
 957 %destructor { parent_rhs_after_value = 0; } PARENT_RHS_AFTER
 958
 959 %{
 960 # include <stdlib.h>
 961   static int merge (YYSTYPE, YYSTYPE);
 962   static void yyerror (char const *);
 963   static int yylex (void);
 964   static int parent_rhs_before_value = 0;
 965   static int merged_value = 0;
 966   static int parent_rhs_after_value = 0;
 967 # define USE(val)
 968 %}
 969
 970 %%
 971
 972 start:
 973   alt1 %dprec 1
 974   | alt2 %dprec 2
 975   ;
 976
 977 alt1:
 978   PARENT_RHS_AFTER {
 979     USE ($1);
 980     parent_rhs_after_value = 0;
 981   }
 982   ;
 983
 984 alt2:
 985   parent_rhs_before merged PARENT_RHS_AFTER {
 986     USE (($1, $2, $3));
 987     parent_rhs_before_value = 0;
 988     merged_value = 0;
 989     parent_rhs_after_value = 0;
 990   }
 991   ;
 992
 993 parent_rhs_before:
 994   {
 995     USE ($$);
 996     parent_rhs_before_value = 1;
 997   }
 998   ;
 999
1000 merged:
1001   %merge<merge> {
1002     USE ($$);
1003     merged_value = 1;
1004   }
1005   | cut %merge<merge> {
1006     USE ($$);
1007     merged_value = 1;
1008   }
1009   ;
1010
1011 cut: { YYACCEPT; } ;
1012
1013 %%
1014
1015 static int
1016 merge (YYSTYPE s1, YYSTYPE s2)
1017 {
1018   /* Not invoked. */
1019   char dummy = s1.dummy + s2.dummy;
1020   return dummy;
1021 }
1022
1023 static void
1024 yyerror (char const *msg)
1025 {
1026   fprintf (stderr, "%s\n", msg);
1027 }
1028
1029 static int
1030 yylex (void)
1031 {
1032   static int const input[] = { PARENT_RHS_AFTER, 0 };
1033   static const int *inputp = input;
1034   if (*inputp == PARENT_RHS_AFTER)
1035     parent_rhs_after_value = 1;
1036   return *inputp++;
1037 }
1038
1039 int
1040 main (void)
1041 {
1042   int exit_status = yyparse ();
1043   if (parent_rhs_before_value)
1044     {
1045       fprintf (stderr, "`parent_rhs_before' destructor not called.\n");
1046       exit_status = 1;
1047     }
1048   if (merged_value)
1049     {
1050       fprintf (stderr, "`merged' destructor not called.\n");
1051       exit_status = 1;
1052     }
1053   if (parent_rhs_after_value)
1054     {
1055       fprintf (stderr, "`PARENT_RHS_AFTER' destructor not called.\n");
1056       exit_status = 1;
1057     }
1058   return exit_status;
1059 }
1060 ]])
1061
1062 AT_CHECK([[bison -o glr-regr12.c glr-regr12.y]], 0, [],
1063 [glr-regr12.y: conflicts: 1 shift/reduce, 1 reduce/reduce
1064 ])
1065 AT_COMPILE([glr-regr12])
1066
1067 AT_CHECK([[./glr-regr12]], 0, [], [])
1068
1069 AT_CLEANUP
1070
1071
1072 ## ------------------------------------------------------------------------- ##
1073 ## Incorrect lookahead during deterministic GLR.  See                        ##
1074 ## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00017.html> and  ##
1075 ## <http://lists.gnu.org/archive/html/bison-patches/2006-01/msg00060.html>.  ##
1076 ## ------------------------------------------------------------------------- ##
1077
1078 AT_SETUP([Incorrect lookahead during deterministic GLR])
1079
1080 AT_DATA_GRAMMAR([glr-regr13.y],
1081 [[
1082 /* Tests:
1083      - Defaulted state with initial yychar: yychar == YYEMPTY.
1084      - Nondefaulted state: yychar != YYEMPTY.
1085      - Defaulted state after lookahead: yychar != YYEMPTY.
1086      - Defaulted state after shift: yychar == YYEMPTY.
1087      - User action changing the lookahead.  */
1088
1089 %{
1090   #include <stdio.h>
1091   static void yyerror (char const *);
1092   static int yylex (void);
1093   static void print_look_ahead (char const *);
1094   #define USE(value)
1095 %}
1096
1097 %union { char value; }
1098 %type <value> 'a' 'b'
1099 %glr-parser
1100 %locations
1101
1102 %%
1103
1104 start:
1105   defstate_init defstate_shift 'b' change_lookahead 'a' {
1106     USE ($3);
1107     print_look_ahead ("start <- defstate_init defstate_shift 'b'");
1108   }
1109   ;
1110 defstate_init:
1111   {
1112     print_look_ahead ("defstate_init <- empty string");
1113   }
1114   ;
1115 defstate_shift:
1116   nondefstate defstate_look 'a' {
1117     USE ($3);
1118     print_look_ahead ("defstate_shift <- nondefstate defstate_look 'a'");
1119   }
1120   ;
1121 defstate_look:
1122   {
1123     print_look_ahead ("defstate_look <- empty string");
1124   }
1125   ;
1126 nondefstate:
1127   {
1128     print_look_ahead ("nondefstate <- empty string");
1129   }
1130   | 'b' {
1131     USE ($1);
1132     print_look_ahead ("nondefstate <- 'b'");
1133   }
1134   ;
1135 change_lookahead:
1136   {
1137     yychar = 'a';
1138   }
1139   ;
1140
1141 %%
1142
1143 static void
1144 yyerror (char const *msg)
1145 {
1146   fprintf (stderr, "%s\n", msg);
1147 }
1148
1149 static int
1150 yylex (void)
1151 {
1152   static char const *input = "ab";
1153   static int i = 0;
1154   yylloc.first_line = yylloc.last_line = 1;
1155   yylloc.first_column = yylloc.last_column = i + 1;
1156   yylval.value = input[i] + 'A' - 'a';
1157   return input[i++];
1158 }
1159
1160 static void
1161 print_look_ahead (char const *reduction)
1162 {
1163   printf ("%s:\n  yychar=", reduction);
1164   if (yychar == YYEMPTY)
1165     printf ("YYEMPTY");
1166   else if (yychar == YYEOF)
1167     printf ("YYEOF");
1168   else
1169     {
1170       printf ("'%c', yylval='", yychar);
1171       if (yylval.value > ' ')
1172         printf ("%c", yylval.value);
1173       printf ("', yylloc=(%d,%d),(%d,%d)",
1174               yylloc.first_line, yylloc.first_column,
1175               yylloc.last_line, yylloc.last_column);
1176     }
1177   printf ("\n");
1178 }
1179
1180 int
1181 main (void)
1182 {
1183   yychar = '#'; /* Not a token in the grammar.  */
1184   yylval.value = '!';
1185   return yyparse ();
1186 }
1187 ]])
1188
1189 AT_CHECK([[bison -o glr-regr13.c glr-regr13.y]], 0, [], [])
1190 AT_COMPILE([glr-regr13])
1191
1192 AT_CHECK([[./glr-regr13]], 0,
1193 [defstate_init <- empty string:
1194   yychar=YYEMPTY
1195 nondefstate <- empty string:
1196   yychar='a', yylval='A', yylloc=(1,1),(1,1)
1197 defstate_look <- empty string:
1198   yychar='a', yylval='A', yylloc=(1,1),(1,1)
1199 defstate_shift <- nondefstate defstate_look 'a':
1200   yychar=YYEMPTY
1201 start <- defstate_init defstate_shift 'b':
1202   yychar=YYEMPTY
1203 ], [])
1204
1205 AT_CLEANUP
1206
1207
1208 ## ------------------------------------------------------------------------- ##
1209 ## Incorrect lookahead during nondeterministic GLR.                          ##
1210 ## ------------------------------------------------------------------------- ##
1211
1212 AT_SETUP([Incorrect lookahead during nondeterministic GLR])
1213
1214 AT_DATA_GRAMMAR([glr-regr14.y],
1215 [[
1216 /* Tests:
1217      - Conflicting actions (split-off parse, which copies lookahead need,
1218        which is necessarily yytrue) and nonconflicting actions (non-split-off
1219        parse) for nondefaulted state: yychar != YYEMPTY.
1220      - Merged deferred actions (lookahead need and RHS from different stack
1221        than the target state) and nonmerged deferred actions (same stack).
1222      - Defaulted state after lookahead: yychar != YYEMPTY.
1223      - Defaulted state after shift: yychar == YYEMPTY.
1224      - yychar != YYEMPTY but lookahead need is yyfalse (a previous stack has
1225        seen the lookahead but current stack has not).
1226      - Exceeding stack capacity (stack explosion), and thus reallocating
1227        lookahead need array.
1228    Note that it does not seem possible to see the initial yychar value during
1229    nondeterministic operation since:
1230      - In order to preserve the initial yychar, only defaulted states may be
1231        entered.
1232      - If only defaulted states are entered, there are no conflicts, so
1233        nondeterministic operation does not start.  */
1234
1235 %union { char value; }
1236
1237 %{
1238   #include <stdio.h>
1239   static void yyerror (char const *);
1240   static int yylex (void);
1241   static void print_look_ahead (char const *);
1242   static char merge (union YYSTYPE, union YYSTYPE);
1243   #define USE(value)
1244 %}
1245
1246 %type <value> 'a' 'b' 'c' 'd' stack_explosion
1247 %glr-parser
1248 %locations
1249
1250 %%
1251
1252 start:
1253   merge 'c' stack_explosion {
1254     USE ($2); USE ($3);
1255     print_look_ahead ("start <- merge 'c' stack_explosion");
1256   }
1257   ;
1258
1259 /* When merging the 2 deferred actions, the lookahead needs are different.  */
1260 merge:
1261   nonconflict1 'a' 'b' nonconflict2 %dprec 1 {
1262     USE ($2); USE ($3);
1263     print_look_ahead ("merge <- nonconflict1 'a' 'b' nonconflict2");
1264   }
1265   | conflict defstate_look 'a' nonconflict2 'b' defstate_shift %dprec 2 {
1266     USE ($3); USE ($5);
1267     print_look_ahead ("merge <- conflict defstate_look 'a' nonconflict2 'b'"
1268                       " defstate_shift");
1269   }
1270   ;
1271
1272 nonconflict1:
1273   {
1274     print_look_ahead ("nonconflict1 <- empty string");
1275   }
1276   ;
1277 nonconflict2:
1278   {
1279     print_look_ahead ("nonconflict2 <- empty string");
1280   }
1281   | 'a' {
1282     USE ($1);
1283     print_look_ahead ("nonconflict2 <- 'a'");
1284   }
1285   ;
1286 conflict:
1287   {
1288     print_look_ahead ("conflict <- empty string");
1289   }
1290   ;
1291 defstate_look:
1292   {
1293     print_look_ahead ("defstate_look <- empty string");
1294   }
1295   ;
1296
1297 /* yychar != YYEMPTY but lookahead need is yyfalse.  */
1298 defstate_shift:
1299   {
1300     print_look_ahead ("defstate_shift <- empty string");
1301   }
1302   ;
1303
1304 stack_explosion:
1305   { $$ = '\0'; }
1306   | alt1 stack_explosion %merge<merge> { $$ = $2; }
1307   | alt2 stack_explosion %merge<merge> { $$ = $2; }
1308   | alt3 stack_explosion %merge<merge> { $$ = $2; }
1309   ;
1310 alt1:
1311   'd' no_look {
1312     USE ($1);
1313     if (yychar != 'd' && yychar != YYEOF)
1314       {
1315         fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
1316       }
1317   }
1318   ;
1319 alt2:
1320   'd' no_look {
1321     USE ($1);
1322     if (yychar != 'd' && yychar != YYEOF)
1323       {
1324         fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
1325       }
1326   }
1327   ;
1328 alt3:
1329   'd' no_look {
1330     USE ($1);
1331     if (yychar != 'd' && yychar != YYEOF)
1332       {
1333         fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
1334       }
1335   }
1336   ;
1337 no_look:
1338   {
1339     if (yychar != YYEMPTY)
1340       {
1341         fprintf (stderr,
1342                  "Found lookahead where shouldn't during stack explosion.\n");
1343       }
1344   }
1345   ;
1346
1347 %%
1348
1349 static void
1350 yyerror (char const *msg)
1351 {
1352   fprintf (stderr, "%s\n", msg);
1353 }
1354
1355 static int
1356 yylex (void)
1357 {
1358   static char const *input = "abcdddd";
1359   static int i = 0;
1360   yylloc.first_line = yylloc.last_line = 1;
1361   yylloc.first_column = yylloc.last_column = i + 1;
1362   yylval.value = input[i] + 'A' - 'a';
1363   return input[i++];
1364 }
1365
1366 static void
1367 print_look_ahead (char const *reduction)
1368 {
1369   printf ("%s:\n  yychar=", reduction);
1370   if (yychar == YYEMPTY)
1371     printf ("YYEMPTY");
1372   else if (yychar == YYEOF)
1373     printf ("YYEOF");
1374   else
1375     {
1376       printf ("'%c', yylval='", yychar);
1377       if (yylval.value > ' ')
1378         printf ("%c", yylval.value);
1379       printf ("', yylloc=(%d,%d),(%d,%d)",
1380               yylloc.first_line, yylloc.first_column,
1381               yylloc.last_line, yylloc.last_column);
1382     }
1383   printf ("\n");
1384 }
1385
1386 static char
1387 merge (union YYSTYPE s1, union YYSTYPE s2)
1388 {
1389   char dummy = s1.value + s2.value;
1390   return dummy;
1391 }
1392
1393 int
1394 main (void)
1395 {
1396   yychar = '#'; /* Not a token in the grammar.  */
1397   yylval.value = '!';
1398   return yyparse ();
1399 }
1400 ]])
1401
1402 AT_CHECK([[bison -o glr-regr14.c glr-regr14.y]], 0, [],
1403 [glr-regr14.y: conflicts: 3 reduce/reduce
1404 ])
1405 AT_COMPILE([glr-regr14])
1406
1407 AT_CHECK([[./glr-regr14]], 0,
1408 [conflict <- empty string:
1409   yychar='a', yylval='A', yylloc=(1,1),(1,1)
1410 defstate_look <- empty string:
1411   yychar='a', yylval='A', yylloc=(1,1),(1,1)
1412 nonconflict2 <- empty string:
1413   yychar='b', yylval='B', yylloc=(1,2),(1,2)
1414 defstate_shift <- empty string:
1415   yychar=YYEMPTY
1416 merge <- conflict defstate_look 'a' nonconflict2 'b' defstate_shift:
1417   yychar=YYEMPTY
1418 start <- merge 'c' stack_explosion:
1419   yychar=YYEOF
1420 ], [])
1421
1422 AT_CLEANUP
1423
1424
1425 ## ------------------------------------------------------------------------- ##
1426 ## Leaked semantic values when reporting ambiguity.                          ##
1427 ## ------------------------------------------------------------------------- ##
1428
1429 AT_SETUP([Leaked semantic values when reporting ambiguity])
1430
1431 AT_DATA_GRAMMAR([glr-regr15.y],
1432 [[
1433 %glr-parser
1434 %destructor { parent_rhs_before_value = 0; } parent_rhs_before
1435
1436 %{
1437 # include <stdlib.h>
1438   static void yyerror (char const *);
1439   static int yylex (void);
1440   static int parent_rhs_before_value = 0;
1441 # define USE(val)
1442 %}
1443
1444 %%
1445
1446 start:
1447   alt1 %dprec 1
1448   | alt2 %dprec 2
1449   ;
1450
1451 /* This stack must be merged into the other stacks *last* (added at the
1452    beginning of the semantic options list) so that yyparse will choose to clean
1453    it up rather than the tree for which some semantic actions have been
1454    performed.  Thus, if yyreportAmbiguity longjmp's to yyparse, the values from
1455    those other trees are not cleaned up.  */
1456 alt1: ;
1457
1458 alt2:
1459   parent_rhs_before ambiguity {
1460     USE ($1);
1461     parent_rhs_before_value = 0;
1462   }
1463   ;
1464
1465 parent_rhs_before:
1466   {
1467     USE ($$);
1468     parent_rhs_before_value = 1;
1469   }
1470   ;
1471
1472 ambiguity: ambiguity1 | ambiguity2 ;
1473 ambiguity1: ;
1474 ambiguity2: ;
1475
1476 %%
1477
1478 static void
1479 yyerror (char const *msg)
1480 {
1481   fprintf (stderr, "%s\n", msg);
1482 }
1483
1484 static int
1485 yylex (void)
1486 {
1487   return 0;
1488 }
1489
1490 int
1491 main (void)
1492 {
1493   int exit_status = yyparse () != 1;
1494   if (parent_rhs_before_value)
1495     {
1496       fprintf (stderr, "`parent_rhs_before' destructor not called.\n");
1497       exit_status = 1;
1498     }
1499   return exit_status;
1500 }
1501 ]])
1502
1503 AT_CHECK([[bison -o glr-regr15.c glr-regr15.y]], 0, [],
1504 [glr-regr15.y: conflicts: 2 reduce/reduce
1505 ])
1506 AT_COMPILE([glr-regr15])
1507
1508 AT_CHECK([[./glr-regr15]], 0, [],
1509 [syntax is ambiguous
1510 ])
1511
1512 AT_CLEANUP
1513
1514
1515 ## ------------------------------------------------------------------------- ##
1516 ## Leaked lookahead after nondeterministic parse syntax error.               ##
1517 ## ------------------------------------------------------------------------- ##
1518
1519 AT_SETUP([Leaked lookahead after nondeterministic parse syntax error])
1520 AT_DATA_GRAMMAR([glr-regr16.y],
1521 [[
1522 %glr-parser
1523 %destructor { lookahead_value = 0; } 'b'
1524
1525 %{
1526 # include <stdlib.h>
1527   static void yyerror (char const *);
1528   static int yylex (void);
1529   static int lookahead_value = 0;
1530 # define USE(val)
1531 %}
1532
1533 %%
1534
1535 start: alt1 'a' | alt2 'a' ;
1536 alt1: ;
1537 alt2: ;
1538
1539 %%
1540
1541 static void
1542 yyerror (char const *msg)
1543 {
1544   fprintf (stderr, "%s\n", msg);
1545 }
1546
1547 static int
1548 yylex (void)
1549 {
1550   static const char *input = "ab";
1551   if (*input == 'b')
1552     lookahead_value = 1;
1553   return *input++;
1554 }
1555
1556 int
1557 main (void)
1558 {
1559   int exit_status = yyparse () != 1;
1560   if (lookahead_value)
1561     {
1562       fprintf (stderr, "Lookahead destructor not called.\n");
1563       exit_status = 1;
1564     }
1565   return exit_status;
1566 }
1567 ]])
1568
1569 AT_CHECK([[bison -o glr-regr16.c glr-regr16.y]], 0, [],
1570 [glr-regr16.y: conflicts: 1 reduce/reduce
1571 ])
1572 AT_COMPILE([glr-regr16])
1573
1574 AT_CHECK([[./glr-regr16]], 0, [],
1575 [syntax error
1576 ])
1577
1578 AT_CLEANUP
1579
1580
1581 ## ------------------------------------------------------------------------- ##
1582 ## Uninitialized location when reporting ambiguity.                          ##
1583 ## ------------------------------------------------------------------------- ##
1584
1585 AT_SETUP([Uninitialized location when reporting ambiguity])
1586 AT_DATA_GRAMMAR([glr-regr17.y],
1587 [[
1588 %glr-parser
1589 %locations
1590 %pure-parser
1591 %error-verbose
1592
1593 %union { int dummy; }
1594
1595 %{
1596   static void yyerror (YYLTYPE *, char const *);
1597   static int yylex (YYSTYPE *, YYLTYPE *);
1598 %}
1599
1600 %initial-action {
1601   @$.first_line = 1;
1602   @$.first_column = 1;
1603   @$.last_line = 1;
1604   @$.last_column = 1;
1605 }
1606
1607 %%
1608
1609 /* Tests multiple levels of yyresolveLocations recursion.  */
1610 start: ambig1 | ambig2 ;
1611 ambig1: sub_ambig1 | sub_ambig2 ;
1612 ambig2: sub_ambig1 | sub_ambig2 ;
1613
1614 /* Tests non-empty RHS as well as empty RHS with either initial location or
1615    location of previous token.  Both empty RHS locations are printed in the
1616    error message.  */
1617 sub_ambig1: empty 'a' 'b' empty ;
1618 sub_ambig2: empty 'a' 'b' empty ;
1619 empty: ;
1620
1621 %%
1622
1623 static void
1624 yyerror (YYLTYPE *locp, char const *msg)
1625 {
1626   fprintf (stderr, "Error at %d.%d-%d.%d: %s.\n", locp->first_line,
1627            locp->first_column, locp->last_line, locp->last_column, msg);
1628 }
1629
1630 /*ARGSUSED*/ static int
1631 yylex (YYSTYPE *lvalp, YYLTYPE *llocp)
1632 {
1633   static const char input[] = "ab";
1634   static const char *inputp = input;
1635   llocp->first_line = llocp->last_line = 2;
1636   llocp->first_column = inputp - input + 1;
1637   llocp->last_column = llocp->first_column + 1;
1638   return *inputp++;
1639 }
1640
1641 int
1642 main (void)
1643 {
1644   return yyparse () != 1;
1645 }
1646 ]])
1647
1648 AT_CHECK([[bison -o glr-regr17.c glr-regr17.y]], 0, [],
1649 [glr-regr17.y: conflicts: 3 reduce/reduce
1650 ])
1651 AT_COMPILE([glr-regr17])
1652
1653 AT_CHECK([[./glr-regr17]], 0, [],
1654 [Error at 1.1-2.3: syntax is ambiguous.
1655 ])
1656
1657 AT_CLEANUP