tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002, 2003, 2004, 2005, 2007, 2009, 2010 Free
   4 # Software Foundation, Inc.
   5
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 AT_BANNER([[Conflicts.]])
  20
  21
  22 ## ---------------- ##
  23 ## S/R in initial.  ##
  24 ## ---------------- ##
  25
  26 # I once hacked Bison in such a way that it lost its reductions on the
  27 # initial state (because it was confusing it with the last state).  It
  28 # took me a while to strip down my failures to this simple case.  So
  29 # make sure it finds the s/r conflict below.
  30
  31 AT_SETUP([S/R in initial])
  32
  33 AT_DATA([[input.y]],
  34 [[%expect 1
  35 %%
  36 exp: e 'e';
  37 e: 'e' | /* Nothing. */;
  38 ]])
  39
  40 AT_BISON_CHECK([-o input.c input.y], 0, [],
  41 [[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */
  42 ]])
  43
  44 AT_CLEANUP
  45
  46
  47 ## ------------------- ##
  48 ## %nonassoc and eof.  ##
  49 ## ------------------- ##
  50
  51 AT_SETUP([%nonassoc and eof])
  52
  53 AT_DATA_GRAMMAR([input.y],
  54 [[
  55 %{
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59
  60 #define YYERROR_VERBOSE 1
  61 static void
  62 yyerror (const char *msg)
  63 {
  64   fprintf (stderr, "%s\n", msg);
  65 }
  66
  67 /* The current argument. */
  68 static const char *input;
  69
  70 static int
  71 yylex (void)
  72 {
  73   static size_t toknum;
  74   if (! (toknum <= strlen (input)))
  75     abort ();
  76   return input[toknum++];
  77 }
  78
  79 %}
  80
  81 %nonassoc '<' '>'
  82
  83 %%
  84 expr: expr '<' expr
  85     | expr '>' expr
  86     | '0'
  87     ;
  88 %%
  89 int
  90 main (int argc, const char *argv[])
  91 {
  92   input = argc <= 1 ? "" : argv[1];
  93   return yyparse ();
  94 }
  95 ]])
  96
  97 # Specify the output files to avoid problems on different file systems.
  98 AT_BISON_CHECK([-o input.c input.y])
  99 AT_COMPILE([input])
 100
 101 AT_PARSER_CHECK([./input '0<0'])
 102 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 103          [syntax error, unexpected '<'
 104 ])
 105
 106 AT_PARSER_CHECK([./input '0>0'])
 107 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 108          [syntax error, unexpected '>'
 109 ])
 110
 111 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 112          [syntax error, unexpected '>'
 113 ])
 114
 115 # We must disable default reductions in inconsistent states in order to
 116 # have an explicit list of all expected tokens.  (However, unless we use
 117 # canonical LR, lookahead sets are merged for different left contexts,
 118 # so it is still possible to have extra incorrect tokens in the expected
 119 # list.  That just doesn't happen to be a problem for this test case.)
 120
 121 AT_BISON_CHECK([-Dlr.default-reductions=consistent -o input.c input.y])
 122 AT_COMPILE([input])
 123
 124 AT_PARSER_CHECK([./input '0<0'])
 125 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 126          [syntax error, unexpected '<', expecting $end
 127 ])
 128
 129 AT_PARSER_CHECK([./input '0>0'])
 130 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 131          [syntax error, unexpected '>', expecting $end
 132 ])
 133
 134 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 135          [syntax error, unexpected '>', expecting $end
 136 ])
 137
 138 AT_CLEANUP
 139
 140
 141
 142 ## -------------------------------------- ##
 143 ## %error-verbose and consistent errors.  ##
 144 ## -------------------------------------- ##
 145
 146 AT_SETUP([[%error-verbose and consistent errors]])
 147
 148 m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
 149
 150 AT_BISON_CHECK([$1[ -o input.c input.y]])
 151 AT_COMPILE([[input]])
 152
 153 m4_pushdef([AT_EXPECTING], [m4_if($3, [ab], [[, expecting 'a' or 'b']],
 154                                   $3, [a],  [[, expecting 'a']],
 155                                   $3, [b],  [[, expecting 'b']])])
 156
 157 AT_PARSER_CHECK([[./input]], [[1]], [],
 158 [[syntax error, unexpected ]$2[]AT_EXPECTING[
 159 ]])
 160
 161 m4_popdef([AT_EXPECTING])
 162
 163 ])
 164
 165 AT_DATA_GRAMMAR([input.y],
 166 [[%code {
 167   #include <assert.h>
 168   #include <stdio.h>
 169   int yylex (void);
 170   void yyerror (char const *);
 171   #define USE(Var)
 172 }
 173
 174 %error-verbose
 175
 176 // The point isn't to test IELR here, but state merging happens to
 177 // complicate the example.
 178 %define lr.type ielr
 179
 180 %nonassoc 'a'
 181
 182 // If yylval=0 here, then we know that the 'a' destructor is being
 183 // invoked incorrectly for the 'b' set in the semantic action below.
 184 // All 'a' tokens are returned by yylex, which sets yylval=1.
 185 %destructor {
 186   if (!$$)
 187     fprintf (stderr, "Wrong destructor.\n");
 188 } 'a'
 189
 190 %%
 191
 192 // The lookahead assigned by the semantic action isn't needed before
 193 // either error action is encountered.  In a previous version of Bison,
 194 // this was a problem as it meant yychar was not translated into yytoken
 195 // before either error action.  The second error action thus invoked a
 196 // destructor that it selected according to the incorrect yytoken.  The
 197 // first error action would have reported an incorrect unexpected token
 198 // except that, due to another bug, the unexpected token is not reported
 199 // at all because the error action is the default action in a consistent
 200 // state.  That bug still needs to be fixed.
 201 start: error-reduce consistent-error 'a' { USE ($3); } ;
 202
 203 error-reduce:
 204   'a' 'a' consistent-reduction consistent-error 'a'
 205   { USE (($1, $2, $5)); }
 206 | 'a' error
 207   { USE ($1); }
 208 ;
 209
 210 consistent-reduction: /*empty*/ {
 211   assert (yychar == YYEMPTY);
 212   yylval = 0;
 213   yychar = 'b';
 214 } ;
 215
 216 consistent-error:
 217   'a' { USE ($1); }
 218 | /*empty*/ %prec 'a'
 219 ;
 220
 221 // Provide another context in which all rules are useful so that this
 222 // test case looks a little more realistic.
 223 start: 'b' consistent-error 'b' ;
 224
 225 %%
 226
 227 int
 228 yylex (void)
 229 {
 230   static char const *input = "aa";
 231   yylval = 1;
 232   return *input++;
 233 }
 234
 235 void
 236 yyerror (char const *msg)
 237 {
 238   fprintf (stderr, "%s\n", msg);
 239 }
 240
 241 int
 242 main (void)
 243 {
 244   return yyparse ();
 245 }
 246 ]])
 247
 248 # See comments in grammar for why this test doesn't succeed.
 249 AT_XFAIL_IF([[:]])
 250
 251 AT_CONSISTENT_ERRORS_CHECK([], [['b']], [[none]])
 252 AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=consistent]],
 253                            [['b']], [[none]])
 254
 255 # Canonical LR doesn't foresee the error for 'a'!
 256 AT_CONSISTENT_ERRORS_CHECK([[-Dlr.default-reductions=accepting]],
 257                            [[$end]], [[a]])
 258 AT_CONSISTENT_ERRORS_CHECK([[-Flr.type=canonical-lr]], [[$end]], [[a]])
 259
 260 m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
 261
 262 AT_CLEANUP
 263
 264
 265
 266 ## ------------------------- ##
 267 ## Unresolved SR Conflicts.  ##
 268 ## ------------------------- ##
 269
 270 AT_SETUP([Unresolved SR Conflicts])
 271
 272 AT_KEYWORDS([report])
 273
 274 AT_DATA([input.y],
 275 [[%token NUM OP
 276 %%
 277 exp: exp OP exp | NUM;
 278 ]])
 279
 280 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 281 [input.y: conflicts: 1 shift/reduce
 282 ])
 283
 284 # Check the contents of the report.
 285 AT_CHECK([cat input.output], [],
 286 [[State 5 conflicts: 1 shift/reduce
 287
 288
 289 Grammar
 290
 291     0 $accept: exp $end
 292
 293     1 exp: exp OP exp
 294     2    | NUM
 295
 296
 297 Terminals, with rules where they appear
 298
 299 $end (0) 0
 300 error (256)
 301 NUM (258) 2
 302 OP (259) 1
 303
 304
 305 Nonterminals, with rules where they appear
 306
 307 $accept (5)
 308     on left: 0
 309 exp (6)
 310     on left: 1 2, on right: 0 1
 311
 312
 313 state 0
 314
 315     0 $accept: . exp $end
 316     1 exp: . exp OP exp
 317     2    | . NUM
 318
 319     NUM  shift, and go to state 1
 320
 321     exp  go to state 2
 322
 323
 324 state 1
 325
 326     2 exp: NUM .
 327
 328     $default  reduce using rule 2 (exp)
 329
 330
 331 state 2
 332
 333     0 $accept: exp . $end
 334     1 exp: exp . OP exp
 335
 336     $end  shift, and go to state 3
 337     OP    shift, and go to state 4
 338
 339
 340 state 3
 341
 342     0 $accept: exp $end .
 343
 344     $default  accept
 345
 346
 347 state 4
 348
 349     1 exp: . exp OP exp
 350     1    | exp OP . exp
 351     2    | . NUM
 352
 353     NUM  shift, and go to state 1
 354
 355     exp  go to state 5
 356
 357
 358 state 5
 359
 360     1 exp: exp . OP exp
 361     1    | exp OP exp .  [$end, OP]
 362
 363     OP  shift, and go to state 4
 364
 365     OP        [reduce using rule 1 (exp)]
 366     $default  reduce using rule 1 (exp)
 367 ]])
 368
 369 AT_CLEANUP
 370
 371
 372
 373 ## ----------------------- ##
 374 ## Resolved SR Conflicts.  ##
 375 ## ----------------------- ##
 376
 377 AT_SETUP([Resolved SR Conflicts])
 378
 379 AT_KEYWORDS([report])
 380
 381 AT_DATA([input.y],
 382 [[%token NUM OP
 383 %left OP
 384 %%
 385 exp: exp OP exp | NUM;
 386 ]])
 387
 388 AT_BISON_CHECK([-o input.c --report=all input.y])
 389
 390 # Check the contents of the report.
 391 AT_CHECK([cat input.output], [],
 392 [[Grammar
 393
 394     0 $accept: exp $end
 395
 396     1 exp: exp OP exp
 397     2    | NUM
 398
 399
 400 Terminals, with rules where they appear
 401
 402 $end (0) 0
 403 error (256)
 404 NUM (258) 2
 405 OP (259) 1
 406
 407
 408 Nonterminals, with rules where they appear
 409
 410 $accept (5)
 411     on left: 0
 412 exp (6)
 413     on left: 1 2, on right: 0 1
 414
 415
 416 state 0
 417
 418     0 $accept: . exp $end
 419     1 exp: . exp OP exp
 420     2    | . NUM
 421
 422     NUM  shift, and go to state 1
 423
 424     exp  go to state 2
 425
 426
 427 state 1
 428
 429     2 exp: NUM .
 430
 431     $default  reduce using rule 2 (exp)
 432
 433
 434 state 2
 435
 436     0 $accept: exp . $end
 437     1 exp: exp . OP exp
 438
 439     $end  shift, and go to state 3
 440     OP    shift, and go to state 4
 441
 442
 443 state 3
 444
 445     0 $accept: exp $end .
 446
 447     $default  accept
 448
 449
 450 state 4
 451
 452     1 exp: . exp OP exp
 453     1    | exp OP . exp
 454     2    | . NUM
 455
 456     NUM  shift, and go to state 1
 457
 458     exp  go to state 5
 459
 460
 461 state 5
 462
 463     1 exp: exp . OP exp
 464     1    | exp OP exp .  [$end, OP]
 465
 466     $default  reduce using rule 1 (exp)
 467
 468     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 469 ]])
 470
 471 AT_CLEANUP
 472
 473
 474 ## -------------------------------- ##
 475 ## Defaulted Conflicted Reduction.  ##
 476 ## -------------------------------- ##
 477
 478 # When there are RR conflicts, some rules are disabled.  Usually it is
 479 # simply displayed as:
 480 #
 481 #    $end           reduce using rule 3 (num)
 482 #    $end           [reduce using rule 4 (id)]
 483 #
 484 # But when `reduce 3' is the default action, we'd produce:
 485 #
 486 #    $end           [reduce using rule 4 (id)]
 487 #    $default    reduce using rule 3 (num)
 488 #
 489 # In this precise case (a reduction is masked by the default
 490 # reduction), we make the `reduce 3' explicit:
 491 #
 492 #    $end           reduce using rule 3 (num)
 493 #    $end           [reduce using rule 4 (id)]
 494 #    $default    reduce using rule 3 (num)
 495 #
 496 # Maybe that's not the best display, but then, please propose something
 497 # else.
 498
 499 AT_SETUP([Defaulted Conflicted Reduction])
 500 AT_KEYWORDS([report])
 501
 502 AT_DATA([input.y],
 503 [[%%
 504 exp: num | id;
 505 num: '0';
 506 id : '0';
 507 %%
 508 ]])
 509
 510 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 511 [[input.y: conflicts: 1 reduce/reduce
 512 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
 513 ]])
 514
 515 # Check the contents of the report.
 516 AT_CHECK([cat input.output], [],
 517 [[Rules useless in parser due to conflicts
 518
 519     4 id: '0'
 520
 521
 522 State 1 conflicts: 1 reduce/reduce
 523
 524
 525 Grammar
 526
 527     0 $accept: exp $end
 528
 529     1 exp: num
 530     2    | id
 531
 532     3 num: '0'
 533
 534     4 id: '0'
 535
 536
 537 Terminals, with rules where they appear
 538
 539 $end (0) 0
 540 '0' (48) 3 4
 541 error (256)
 542
 543
 544 Nonterminals, with rules where they appear
 545
 546 $accept (4)
 547     on left: 0
 548 exp (5)
 549     on left: 1 2, on right: 0
 550 num (6)
 551     on left: 3, on right: 1
 552 id (7)
 553     on left: 4, on right: 2
 554
 555
 556 state 0
 557
 558     0 $accept: . exp $end
 559     1 exp: . num
 560     2    | . id
 561     3 num: . '0'
 562     4 id: . '0'
 563
 564     '0'  shift, and go to state 1
 565
 566     exp  go to state 2
 567     num  go to state 3
 568     id   go to state 4
 569
 570
 571 state 1
 572
 573     3 num: '0' .  [$end]
 574     4 id: '0' .  [$end]
 575
 576     $end      reduce using rule 3 (num)
 577     $end      [reduce using rule 4 (id)]
 578     $default  reduce using rule 3 (num)
 579
 580
 581 state 2
 582
 583     0 $accept: exp . $end
 584
 585     $end  shift, and go to state 5
 586
 587
 588 state 3
 589
 590     1 exp: num .
 591
 592     $default  reduce using rule 1 (exp)
 593
 594
 595 state 4
 596
 597     2 exp: id .
 598
 599     $default  reduce using rule 2 (exp)
 600
 601
 602 state 5
 603
 604     0 $accept: exp $end .
 605
 606     $default  accept
 607 ]])
 608
 609 AT_CLEANUP
 610
 611
 612
 613
 614 ## -------------------- ##
 615 ## %expect not enough.  ##
 616 ## -------------------- ##
 617
 618 AT_SETUP([%expect not enough])
 619
 620 AT_DATA([input.y],
 621 [[%token NUM OP
 622 %expect 0
 623 %%
 624 exp: exp OP exp | NUM;
 625 ]])
 626
 627 AT_BISON_CHECK([-o input.c input.y], 1, [],
 628 [input.y: conflicts: 1 shift/reduce
 629 input.y: expected 0 shift/reduce conflicts
 630 ])
 631 AT_CLEANUP
 632
 633
 634 ## --------------- ##
 635 ## %expect right.  ##
 636 ## --------------- ##
 637
 638 AT_SETUP([%expect right])
 639
 640 AT_DATA([input.y],
 641 [[%token NUM OP
 642 %expect 1
 643 %%
 644 exp: exp OP exp | NUM;
 645 ]])
 646
 647 AT_BISON_CHECK([-o input.c input.y])
 648 AT_CLEANUP
 649
 650
 651 ## ------------------ ##
 652 ## %expect too much.  ##
 653 ## ------------------ ##
 654
 655 AT_SETUP([%expect too much])
 656
 657 AT_DATA([input.y],
 658 [[%token NUM OP
 659 %expect 2
 660 %%
 661 exp: exp OP exp | NUM;
 662 ]])
 663
 664 AT_BISON_CHECK([-o input.c input.y], 1, [],
 665 [input.y: conflicts: 1 shift/reduce
 666 input.y: expected 2 shift/reduce conflicts
 667 ])
 668 AT_CLEANUP
 669
 670
 671 ## ------------------------------- ##
 672 ## %expect with reduce conflicts.  ##
 673 ## ------------------------------- ##
 674
 675 AT_SETUP([%expect with reduce conflicts])
 676
 677 AT_DATA([input.y],
 678 [[%expect 0
 679 %%
 680 program: a 'a' | a a;
 681 a: 'a';
 682 ]])
 683
 684 AT_BISON_CHECK([-o input.c input.y], 1, [],
 685 [input.y: conflicts: 1 reduce/reduce
 686 input.y: expected 0 reduce/reduce conflicts
 687 ])
 688 AT_CLEANUP
 689
 690
 691 ## ------------------------- ##
 692 ## %prec with user strings.  ##
 693 ## ------------------------- ##
 694
 695 AT_SETUP([%prec with user string])
 696
 697 AT_DATA([[input.y]],
 698 [[%%
 699 exp:
 700   "foo" %prec "foo"
 701 ;
 702 ]])
 703
 704 AT_BISON_CHECK([-o input.c input.y])
 705 AT_CLEANUP
 706
 707
 708 ## -------------------------------- ##
 709 ## %no-default-prec without %prec.  ##
 710 ## -------------------------------- ##
 711
 712 AT_SETUP([%no-default-prec without %prec])
 713
 714 AT_DATA([[input.y]],
 715 [[%left '+'
 716 %left '*'
 717
 718 %%
 719
 720 %no-default-prec;
 721
 722 e:   e '+' e
 723    | e '*' e
 724    | '0'
 725    ;
 726 ]])
 727
 728 AT_BISON_CHECK([-o input.c input.y], 0, [],
 729 [[input.y: conflicts: 4 shift/reduce
 730 ]])
 731 AT_CLEANUP
 732
 733
 734 ## ----------------------------- ##
 735 ## %no-default-prec with %prec.  ##
 736 ## ----------------------------- ##
 737
 738 AT_SETUP([%no-default-prec with %prec])
 739
 740 AT_DATA([[input.y]],
 741 [[%left '+'
 742 %left '*'
 743
 744 %%
 745
 746 %no-default-prec;
 747
 748 e:   e '+' e %prec '+'
 749    | e '*' e %prec '*'
 750    | '0'
 751    ;
 752 ]])
 753
 754 AT_BISON_CHECK([-o input.c input.y])
 755 AT_CLEANUP
 756
 757
 758 ## --------------- ##
 759 ## %default-prec.  ##
 760 ## --------------- ##
 761
 762 AT_SETUP([%default-prec])
 763
 764 AT_DATA([[input.y]],
 765 [[%left '+'
 766 %left '*'
 767
 768 %%
 769
 770 %default-prec;
 771
 772 e:   e '+' e
 773    | e '*' e
 774    | '0'
 775    ;
 776 ]])
 777
 778 AT_BISON_CHECK([-o input.c input.y])
 779 AT_CLEANUP
 780
 781
 782 ## ---------------------------------------------- ##
 783 ## Unreachable States After Conflict Resolution.  ##
 784 ## ---------------------------------------------- ##
 785
 786 AT_SETUP([[Unreachable States After Conflict Resolution]])
 787
 788 # If conflict resolution makes states unreachable, remove those states, report
 789 # rules that are then unused, and don't report conflicts in those states.  Test
 790 # what happens when a nonterminal becomes useless as a result of state removal
 791 # since that causes lalr.o's goto map to be rewritten.
 792
 793 AT_DATA([[input.y]],
 794 [[%output "input.c"
 795 %left 'a'
 796
 797 %%
 798
 799 start: resolved_conflict 'a' reported_conflicts 'a' ;
 800
 801 /* S/R conflict resolved as reduce, so the state with item
 802  * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
 803  * unreachable, and the associated production is useless.  */
 804 resolved_conflict:
 805     'a' unreachable1
 806   | %prec 'a'
 807   ;
 808
 809 /* S/R conflict that need not be reported since it is unreachable because of
 810  * the previous conflict resolution.  Nonterminal unreachable1 and all its
 811  * productions are useless.  */
 812 unreachable1:
 813     'a' unreachable2
 814   |
 815   ;
 816
 817 /* Likewise for a R/R conflict and nonterminal unreachable2.  */
 818 unreachable2: | ;
 819
 820 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
 821  * when their states are renumbered due to state removal.  */
 822 reported_conflicts:
 823     'a'
 824   | 'a'
 825   |
 826   ;
 827
 828 ]])
 829
 830 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 831 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
 832 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
 833 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
 834 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 835 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 836 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 837 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 838 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 839 ]])
 840
 841 AT_CHECK([[cat input.output]], 0,
 842 [[Rules useless in parser due to conflicts
 843
 844     2 resolved_conflict: 'a' unreachable1
 845
 846     4 unreachable1: 'a' unreachable2
 847     5             | /* empty */
 848
 849     6 unreachable2: /* empty */
 850     7             | /* empty */
 851
 852     9 reported_conflicts: 'a'
 853    10                   | /* empty */
 854
 855
 856 State 4 conflicts: 1 shift/reduce
 857 State 5 conflicts: 1 reduce/reduce
 858
 859
 860 Grammar
 861
 862     0 $accept: start $end
 863
 864     1 start: resolved_conflict 'a' reported_conflicts 'a'
 865
 866     2 resolved_conflict: 'a' unreachable1
 867     3                  | /* empty */
 868
 869     4 unreachable1: 'a' unreachable2
 870     5             | /* empty */
 871
 872     6 unreachable2: /* empty */
 873     7             | /* empty */
 874
 875     8 reported_conflicts: 'a'
 876     9                   | 'a'
 877    10                   | /* empty */
 878
 879
 880 Terminals, with rules where they appear
 881
 882 $end (0) 0
 883 'a' (97) 1 2 4 8 9
 884 error (256)
 885
 886
 887 Nonterminals, with rules where they appear
 888
 889 $accept (4)
 890     on left: 0
 891 start (5)
 892     on left: 1, on right: 0
 893 resolved_conflict (6)
 894     on left: 2 3, on right: 1
 895 unreachable1 (7)
 896     on left: 4 5, on right: 2
 897 unreachable2 (8)
 898     on left: 6 7, on right: 4
 899 reported_conflicts (9)
 900     on left: 8 9 10, on right: 1
 901
 902
 903 state 0
 904
 905     0 $accept: . start $end
 906     1 start: . resolved_conflict 'a' reported_conflicts 'a'
 907     2 resolved_conflict: . 'a' unreachable1
 908     3                  | .  ['a']
 909
 910     $default  reduce using rule 3 (resolved_conflict)
 911
 912     start              go to state 1
 913     resolved_conflict  go to state 2
 914
 915     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 916
 917
 918 state 1
 919
 920     0 $accept: start . $end
 921
 922     $end  shift, and go to state 3
 923
 924
 925 state 2
 926
 927     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 928
 929     'a'  shift, and go to state 4
 930
 931
 932 state 3
 933
 934     0 $accept: start $end .
 935
 936     $default  accept
 937
 938
 939 state 4
 940
 941     1 start: resolved_conflict 'a' . reported_conflicts 'a'
 942     8 reported_conflicts: . 'a'
 943     9                   | . 'a'
 944    10                   | .  ['a']
 945
 946     'a'  shift, and go to state 5
 947
 948     'a'  [reduce using rule 10 (reported_conflicts)]
 949
 950     reported_conflicts  go to state 6
 951
 952
 953 state 5
 954
 955     8 reported_conflicts: 'a' .  ['a']
 956     9                   | 'a' .  ['a']
 957
 958     'a'       reduce using rule 8 (reported_conflicts)
 959     'a'       [reduce using rule 9 (reported_conflicts)]
 960     $default  reduce using rule 8 (reported_conflicts)
 961
 962
 963 state 6
 964
 965     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 966
 967     'a'  shift, and go to state 7
 968
 969
 970 state 7
 971
 972     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 973
 974     $default  reduce using rule 1 (start)
 975 ]])
 976
 977 AT_DATA([[input-keep.y]],
 978 [[%define lr.keep-unreachable-states
 979 ]])
 980 AT_CHECK([[cat input.y >> input-keep.y]])
 981
 982 AT_BISON_CHECK([[input-keep.y]], 0, [],
 983 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
 984 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 985 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 986 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 987 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 988 ]])
 989
 990 AT_CLEANUP
 991
 992
 993 ## ------------------------------------------------------------ ##
 994 ## Solved conflicts report for multiple reductions in a state.  ##
 995 ## ------------------------------------------------------------ ##
 996
 997 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
 998
 999 # Used to lose earlier solved conflict messages even within a single S/R/R.
1000
1001 AT_DATA([[input.y]],
1002 [[%left 'a'
1003 %right 'b'
1004 %right 'c'
1005 %right 'd'
1006 %%
1007 start:
1008     'a'
1009   | empty_a 'a'
1010   | 'b'
1011   | empty_b 'b'
1012   | 'c'
1013   | empty_c1 'c'
1014   | empty_c2 'c'
1015   | empty_c3 'c'
1016   ;
1017 empty_a: %prec 'a' ;
1018 empty_b: %prec 'b' ;
1019 empty_c1: %prec 'c' ;
1020 empty_c2: %prec 'c' ;
1021 empty_c3: %prec 'd' ;
1022 ]])
1023 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1024 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
1025 [[state 0
1026
1027     0 $accept: . start $end
1028     1 start: . 'a'
1029     2      | . empty_a 'a'
1030     3      | . 'b'
1031     4      | . empty_b 'b'
1032     5      | . 'c'
1033     6      | . empty_c1 'c'
1034     7      | . empty_c2 'c'
1035     8      | . empty_c3 'c'
1036     9 empty_a: .  ['a']
1037    10 empty_b: .  []
1038    11 empty_c1: .  []
1039    12 empty_c2: .  []
1040    13 empty_c3: .  ['c']
1041
1042     'b'  shift, and go to state 1
1043
1044     'c'       reduce using rule 13 (empty_c3)
1045     $default  reduce using rule 9 (empty_a)
1046
1047     start     go to state 2
1048     empty_a   go to state 3
1049     empty_b   go to state 4
1050     empty_c1  go to state 5
1051     empty_c2  go to state 6
1052     empty_c3  go to state 7
1053
1054     Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
1055     Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
1056     Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
1057     Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
1058     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
1059
1060
1061 state 1
1062 ]])
1063
1064 AT_CLEANUP
1065
1066
1067 ## ------------------------------------------------------------ ##
1068 ## %nonassoc error actions for multiple reductions in a state.  ##
1069 ## ------------------------------------------------------------ ##
1070
1071 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
1072 # multiple reductions in a state.
1073
1074 # For a %nonassoc error action token, used to print the first remaining
1075 # reduction on that token without brackets.
1076
1077 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
1078
1079 AT_DATA([[input.y]],
1080 [[%nonassoc 'a' 'b' 'c'
1081 %%
1082 start:
1083     'a'
1084   | empty_a 'a'
1085   | 'b'
1086   | empty_b 'b'
1087   | 'c'
1088   | empty_c1 'c'
1089   | empty_c2 'c'
1090   | empty_c3 'c'
1091   ;
1092 empty_a: %prec 'a' ;
1093 empty_b: %prec 'b' ;
1094 empty_c1: %prec 'c' ;
1095 empty_c2: %prec 'c' ;
1096 empty_c3: %prec 'c' ;
1097 ]])
1098
1099 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1100 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
1101 [[state 0
1102
1103     0 $accept: . start $end
1104     1 start: . 'a'
1105     2      | . empty_a 'a'
1106     3      | . 'b'
1107     4      | . empty_b 'b'
1108     5      | . 'c'
1109     6      | . empty_c1 'c'
1110     7      | . empty_c2 'c'
1111     8      | . empty_c3 'c'
1112     9 empty_a: .  []
1113    10 empty_b: .  []
1114    11 empty_c1: .  []
1115    12 empty_c2: .  ['c']
1116    13 empty_c3: .  ['c']
1117
1118     'a'  error (nonassociative)
1119     'b'  error (nonassociative)
1120     'c'  error (nonassociative)
1121
1122     'c'  [reduce using rule 12 (empty_c2)]
1123     'c'  [reduce using rule 13 (empty_c3)]
1124
1125     start     go to state 1
1126     empty_a   go to state 2
1127     empty_b   go to state 3
1128     empty_c1  go to state 4
1129     empty_c2  go to state 5
1130     empty_c3  go to state 6
1131
1132     Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1133     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1134     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1135
1136
1137 state 1
1138 ]])
1139 AT_CLEANUP