tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008, 2009 Free Software
   4 # 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 # FIXME: This is an actual bug, but a new one, in the sense that
 103 # no one has ever spotted it!  The messages are *wrong*: there should
 104 # be nothing there, it should be expected eof.
 105 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 106          [syntax error, unexpected '<', expecting '<' or '>'
 107 ])
 108
 109 AT_PARSER_CHECK([./input '0>0'])
 110 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 111          [syntax error, unexpected '>', expecting '<' or '>'
 112 ])
 113
 114 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 115          [syntax error, unexpected '>', expecting '<' or '>'
 116 ])
 117
 118 AT_CLEANUP
 119
 120
 121
 122 ## ------------------------- ##
 123 ## Unresolved SR Conflicts.  ##
 124 ## ------------------------- ##
 125
 126 AT_SETUP([Unresolved SR Conflicts])
 127
 128 AT_KEYWORDS([report])
 129
 130 AT_DATA([input.y],
 131 [[%token NUM OP
 132 %%
 133 exp: exp OP exp | NUM;
 134 ]])
 135
 136 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 137 [input.y: conflicts: 1 shift/reduce
 138 ])
 139
 140 # Check the contents of the report.
 141 AT_CHECK([cat input.output], [],
 142 [[State 5 conflicts: 1 shift/reduce
 143
 144
 145 Grammar
 146
 147     0 $accept: exp $end
 148
 149     1 exp: exp OP exp
 150     2    | NUM
 151
 152
 153 Terminals, with rules where they appear
 154
 155 $end (0) 0
 156 error (256)
 157 NUM (258) 2
 158 OP (259) 1
 159
 160
 161 Nonterminals, with rules where they appear
 162
 163 $accept (5)
 164     on left: 0
 165 exp (6)
 166     on left: 1 2, on right: 0 1
 167
 168
 169 state 0
 170
 171     0 $accept: . exp $end
 172     1 exp: . exp OP exp
 173     2    | . NUM
 174
 175     NUM  shift, and go to state 1
 176
 177     exp  go to state 2
 178
 179
 180 state 1
 181
 182     2 exp: NUM .
 183
 184     $default  reduce using rule 2 (exp)
 185
 186
 187 state 2
 188
 189     0 $accept: exp . $end
 190     1 exp: exp . OP exp
 191
 192     $end  shift, and go to state 3
 193     OP    shift, and go to state 4
 194
 195
 196 state 3
 197
 198     0 $accept: exp $end .
 199
 200     $default  accept
 201
 202
 203 state 4
 204
 205     1 exp: . exp OP exp
 206     1    | exp OP . exp
 207     2    | . NUM
 208
 209     NUM  shift, and go to state 1
 210
 211     exp  go to state 5
 212
 213
 214 state 5
 215
 216     1 exp: exp . OP exp
 217     1    | exp OP exp .  [$end, OP]
 218
 219     OP  shift, and go to state 4
 220
 221     OP        [reduce using rule 1 (exp)]
 222     $default  reduce using rule 1 (exp)
 223 ]])
 224
 225 AT_CLEANUP
 226
 227
 228
 229 ## ----------------------- ##
 230 ## Resolved SR Conflicts.  ##
 231 ## ----------------------- ##
 232
 233 AT_SETUP([Resolved SR Conflicts])
 234
 235 AT_KEYWORDS([report])
 236
 237 AT_DATA([input.y],
 238 [[%token NUM OP
 239 %left OP
 240 %%
 241 exp: exp OP exp | NUM;
 242 ]])
 243
 244 AT_BISON_CHECK([-o input.c --report=all input.y])
 245
 246 # Check the contents of the report.
 247 AT_CHECK([cat input.output], [],
 248 [[Grammar
 249
 250     0 $accept: exp $end
 251
 252     1 exp: exp OP exp
 253     2    | NUM
 254
 255
 256 Terminals, with rules where they appear
 257
 258 $end (0) 0
 259 error (256)
 260 NUM (258) 2
 261 OP (259) 1
 262
 263
 264 Nonterminals, with rules where they appear
 265
 266 $accept (5)
 267     on left: 0
 268 exp (6)
 269     on left: 1 2, on right: 0 1
 270
 271
 272 state 0
 273
 274     0 $accept: . exp $end
 275     1 exp: . exp OP exp
 276     2    | . NUM
 277
 278     NUM  shift, and go to state 1
 279
 280     exp  go to state 2
 281
 282
 283 state 1
 284
 285     2 exp: NUM .
 286
 287     $default  reduce using rule 2 (exp)
 288
 289
 290 state 2
 291
 292     0 $accept: exp . $end
 293     1 exp: exp . OP exp
 294
 295     $end  shift, and go to state 3
 296     OP    shift, and go to state 4
 297
 298
 299 state 3
 300
 301     0 $accept: exp $end .
 302
 303     $default  accept
 304
 305
 306 state 4
 307
 308     1 exp: . exp OP exp
 309     1    | exp OP . exp
 310     2    | . NUM
 311
 312     NUM  shift, and go to state 1
 313
 314     exp  go to state 5
 315
 316
 317 state 5
 318
 319     1 exp: exp . OP exp
 320     1    | exp OP exp .  [$end, OP]
 321
 322     $default  reduce using rule 1 (exp)
 323
 324     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 325 ]])
 326
 327 AT_CLEANUP
 328
 329
 330 ## ---------------------- ##
 331 ## %precedence suffices.  ##
 332 ## ---------------------- ##
 333
 334 AT_SETUP([%precedence suffices])
 335
 336 AT_DATA([input.y],
 337 [[%precedence "then"
 338 %precedence "else"
 339 %%
 340 stmt:
 341   "if" cond "then" stmt
 342 | "if" cond "then" stmt "else" stmt
 343 | "stmt"
 344 ;
 345
 346 cond:
 347   "exp"
 348 ;
 349 ]])
 350
 351 AT_BISON_CHECK([-o input.c input.y])
 352
 353 AT_CLEANUP
 354
 355
 356 ## ------------------------------ ##
 357 ## %precedence does not suffice.  ##
 358 ## ------------------------------ ##
 359
 360 AT_SETUP([%precedence does not suffice])
 361
 362 AT_DATA([input.y],
 363 [[%precedence "then"
 364 %precedence "else"
 365 %%
 366 stmt:
 367   "if" cond "then" stmt
 368 | "if" cond "then" stmt "else" stmt
 369 | "stmt"
 370 ;
 371
 372 cond:
 373   "exp"
 374 | cond "then" cond
 375 ;
 376 ]])
 377
 378 AT_BISON_CHECK([-o input.c input.y], 0, [],
 379 [[input.y: conflicts: 1 shift/reduce
 380 input.y:12.3-18: warning: rule useless in parser due to conflicts: cond: cond "then" cond
 381 ]])
 382
 383 AT_CLEANUP
 384
 385
 386 ## -------------------------------- ##
 387 ## Defaulted Conflicted Reduction.  ##
 388 ## -------------------------------- ##
 389
 390 # When there are RR conflicts, some rules are disabled.  Usually it is
 391 # simply displayed as:
 392 #
 393 #    $end           reduce using rule 3 (num)
 394 #    $end           [reduce using rule 4 (id)]
 395 #
 396 # But when `reduce 3' is the default action, we'd produce:
 397 #
 398 #    $end           [reduce using rule 4 (id)]
 399 #    $default    reduce using rule 3 (num)
 400 #
 401 # In this precise case (a reduction is masked by the default
 402 # reduction), we make the `reduce 3' explicit:
 403 #
 404 #    $end           reduce using rule 3 (num)
 405 #    $end           [reduce using rule 4 (id)]
 406 #    $default    reduce using rule 3 (num)
 407 #
 408 # Maybe that's not the best display, but then, please propose something
 409 # else.
 410
 411 AT_SETUP([Defaulted Conflicted Reduction])
 412 AT_KEYWORDS([report])
 413
 414 AT_DATA([input.y],
 415 [[%%
 416 exp: num | id;
 417 num: '0';
 418 id : '0';
 419 %%
 420 ]])
 421
 422 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
 423 [[input.y: conflicts: 1 reduce/reduce
 424 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
 425 ]])
 426
 427 # Check the contents of the report.
 428 AT_CHECK([cat input.output], [],
 429 [[Rules useless in parser due to conflicts
 430
 431     4 id: '0'
 432
 433
 434 State 1 conflicts: 1 reduce/reduce
 435
 436
 437 Grammar
 438
 439     0 $accept: exp $end
 440
 441     1 exp: num
 442     2    | id
 443
 444     3 num: '0'
 445
 446     4 id: '0'
 447
 448
 449 Terminals, with rules where they appear
 450
 451 $end (0) 0
 452 '0' (48) 3 4
 453 error (256)
 454
 455
 456 Nonterminals, with rules where they appear
 457
 458 $accept (4)
 459     on left: 0
 460 exp (5)
 461     on left: 1 2, on right: 0
 462 num (6)
 463     on left: 3, on right: 1
 464 id (7)
 465     on left: 4, on right: 2
 466
 467
 468 state 0
 469
 470     0 $accept: . exp $end
 471     1 exp: . num
 472     2    | . id
 473     3 num: . '0'
 474     4 id: . '0'
 475
 476     '0'  shift, and go to state 1
 477
 478     exp  go to state 2
 479     num  go to state 3
 480     id   go to state 4
 481
 482
 483 state 1
 484
 485     3 num: '0' .  [$end]
 486     4 id: '0' .  [$end]
 487
 488     $end      reduce using rule 3 (num)
 489     $end      [reduce using rule 4 (id)]
 490     $default  reduce using rule 3 (num)
 491
 492
 493 state 2
 494
 495     0 $accept: exp . $end
 496
 497     $end  shift, and go to state 5
 498
 499
 500 state 3
 501
 502     1 exp: num .
 503
 504     $default  reduce using rule 1 (exp)
 505
 506
 507 state 4
 508
 509     2 exp: id .
 510
 511     $default  reduce using rule 2 (exp)
 512
 513
 514 state 5
 515
 516     0 $accept: exp $end .
 517
 518     $default  accept
 519 ]])
 520
 521 AT_CLEANUP
 522
 523
 524
 525
 526 ## -------------------- ##
 527 ## %expect not enough.  ##
 528 ## -------------------- ##
 529
 530 AT_SETUP([%expect not enough])
 531
 532 AT_DATA([input.y],
 533 [[%token NUM OP
 534 %expect 0
 535 %%
 536 exp: exp OP exp | NUM;
 537 ]])
 538
 539 AT_BISON_CHECK([-o input.c input.y], 1, [],
 540 [input.y: conflicts: 1 shift/reduce
 541 input.y: expected 0 shift/reduce conflicts
 542 ])
 543 AT_CLEANUP
 544
 545
 546 ## --------------- ##
 547 ## %expect right.  ##
 548 ## --------------- ##
 549
 550 AT_SETUP([%expect right])
 551
 552 AT_DATA([input.y],
 553 [[%token NUM OP
 554 %expect 1
 555 %%
 556 exp: exp OP exp | NUM;
 557 ]])
 558
 559 AT_BISON_CHECK([-o input.c input.y])
 560 AT_CLEANUP
 561
 562
 563 ## ------------------ ##
 564 ## %expect too much.  ##
 565 ## ------------------ ##
 566
 567 AT_SETUP([%expect too much])
 568
 569 AT_DATA([input.y],
 570 [[%token NUM OP
 571 %expect 2
 572 %%
 573 exp: exp OP exp | NUM;
 574 ]])
 575
 576 AT_BISON_CHECK([-o input.c input.y], 1, [],
 577 [input.y: conflicts: 1 shift/reduce
 578 input.y: expected 2 shift/reduce conflicts
 579 ])
 580 AT_CLEANUP
 581
 582
 583 ## ------------------------------ ##
 584 ## %expect with reduce conflicts  ##
 585 ## ------------------------------ ##
 586
 587 AT_SETUP([%expect with reduce conflicts])
 588
 589 AT_DATA([input.y],
 590 [[%expect 0
 591 %%
 592 program: a 'a' | a a;
 593 a: 'a';
 594 ]])
 595
 596 AT_BISON_CHECK([-o input.c input.y], 1, [],
 597 [input.y: conflicts: 1 reduce/reduce
 598 input.y: expected 0 reduce/reduce conflicts
 599 ])
 600 AT_CLEANUP
 601
 602
 603 ## ------------------------------- ##
 604 ## %no-default-prec without %prec  ##
 605 ## ------------------------------- ##
 606
 607 AT_SETUP([%no-default-prec without %prec])
 608
 609 AT_DATA([[input.y]],
 610 [[%left '+'
 611 %left '*'
 612
 613 %%
 614
 615 %no-default-prec;
 616
 617 e:   e '+' e
 618    | e '*' e
 619    | '0'
 620    ;
 621 ]])
 622
 623 AT_BISON_CHECK([-o input.c input.y], 0, [],
 624 [[input.y: conflicts: 4 shift/reduce
 625 ]])
 626 AT_CLEANUP
 627
 628
 629 ## ---------------------------- ##
 630 ## %no-default-prec with %prec  ##
 631 ## ---------------------------- ##
 632
 633 AT_SETUP([%no-default-prec with %prec])
 634
 635 AT_DATA([[input.y]],
 636 [[%left '+'
 637 %left '*'
 638
 639 %%
 640
 641 %no-default-prec;
 642
 643 e:   e '+' e %prec '+'
 644    | e '*' e %prec '*'
 645    | '0'
 646    ;
 647 ]])
 648
 649 AT_BISON_CHECK([-o input.c input.y])
 650 AT_CLEANUP
 651
 652
 653 ## ---------------- ##
 654 ## %default-prec    ##
 655 ## ---------------- ##
 656
 657 AT_SETUP([%default-prec])
 658
 659 AT_DATA([[input.y]],
 660 [[%left '+'
 661 %left '*'
 662
 663 %%
 664
 665 %default-prec;
 666
 667 e:   e '+' e
 668    | e '*' e
 669    | '0'
 670    ;
 671 ]])
 672
 673 AT_BISON_CHECK([-o input.c input.y])
 674 AT_CLEANUP
 675
 676
 677 ## ---------------------------------------------- ##
 678 ## Unreachable States After Conflict Resolution.  ##
 679 ## ---------------------------------------------- ##
 680
 681 AT_SETUP([[Unreachable States After Conflict Resolution]])
 682
 683 # If conflict resolution makes states unreachable, remove those states, report
 684 # rules that are then unused, and don't report conflicts in those states.  Test
 685 # what happens when a nonterminal becomes useless as a result of state removal
 686 # since that causes lalr.o's goto map to be rewritten.
 687
 688 AT_DATA([[input.y]],
 689 [[%output "input.c"
 690 %left 'a'
 691
 692 %%
 693
 694 start: resolved_conflict 'a' reported_conflicts 'a' ;
 695
 696 /* S/R conflict resolved as reduce, so the state with item
 697  * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
 698  * unreachable, and the associated production is useless.  */
 699 resolved_conflict:
 700     'a' unreachable1
 701   | %prec 'a'
 702   ;
 703
 704 /* S/R conflict that need not be reported since it is unreachable because of
 705  * the previous conflict resolution.  Nonterminal unreachable1 and all its
 706  * productions are useless.  */
 707 unreachable1:
 708     'a' unreachable2
 709   |
 710   ;
 711
 712 /* Likewise for a R/R conflict and nonterminal unreachable2.  */
 713 unreachable2: | ;
 714
 715 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
 716  * when their states are renumbered due to state removal.  */
 717 reported_conflicts:
 718     'a'
 719   | 'a'
 720   |
 721   ;
 722
 723 ]])
 724
 725 AT_BISON_CHECK([[--report=all input.y]], 0, [],
 726 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
 727 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
 728 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
 729 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 730 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 731 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 732 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 733 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 734 ]])
 735
 736 AT_CHECK([[cat input.output]], 0,
 737 [[Rules useless in parser due to conflicts
 738
 739     2 resolved_conflict: 'a' unreachable1
 740
 741     4 unreachable1: 'a' unreachable2
 742     5             | /* empty */
 743
 744     6 unreachable2: /* empty */
 745     7             | /* empty */
 746
 747     9 reported_conflicts: 'a'
 748    10                   | /* empty */
 749
 750
 751 State 4 conflicts: 1 shift/reduce
 752 State 5 conflicts: 1 reduce/reduce
 753
 754
 755 Grammar
 756
 757     0 $accept: start $end
 758
 759     1 start: resolved_conflict 'a' reported_conflicts 'a'
 760
 761     2 resolved_conflict: 'a' unreachable1
 762     3                  | /* empty */
 763
 764     4 unreachable1: 'a' unreachable2
 765     5             | /* empty */
 766
 767     6 unreachable2: /* empty */
 768     7             | /* empty */
 769
 770     8 reported_conflicts: 'a'
 771     9                   | 'a'
 772    10                   | /* empty */
 773
 774
 775 Terminals, with rules where they appear
 776
 777 $end (0) 0
 778 'a' (97) 1 2 4 8 9
 779 error (256)
 780
 781
 782 Nonterminals, with rules where they appear
 783
 784 $accept (4)
 785     on left: 0
 786 start (5)
 787     on left: 1, on right: 0
 788 resolved_conflict (6)
 789     on left: 2 3, on right: 1
 790 unreachable1 (7)
 791     on left: 4 5, on right: 2
 792 unreachable2 (8)
 793     on left: 6 7, on right: 4
 794 reported_conflicts (9)
 795     on left: 8 9 10, on right: 1
 796
 797
 798 state 0
 799
 800     0 $accept: . start $end
 801     1 start: . resolved_conflict 'a' reported_conflicts 'a'
 802     2 resolved_conflict: . 'a' unreachable1
 803     3                  | .  ['a']
 804
 805     $default  reduce using rule 3 (resolved_conflict)
 806
 807     start              go to state 1
 808     resolved_conflict  go to state 2
 809
 810     Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
 811
 812
 813 state 1
 814
 815     0 $accept: start . $end
 816
 817     $end  shift, and go to state 3
 818
 819
 820 state 2
 821
 822     1 start: resolved_conflict . 'a' reported_conflicts 'a'
 823
 824     'a'  shift, and go to state 4
 825
 826
 827 state 3
 828
 829     0 $accept: start $end .
 830
 831     $default  accept
 832
 833
 834 state 4
 835
 836     1 start: resolved_conflict 'a' . reported_conflicts 'a'
 837     8 reported_conflicts: . 'a'
 838     9                   | . 'a'
 839    10                   | .  ['a']
 840
 841     'a'  shift, and go to state 5
 842
 843     'a'  [reduce using rule 10 (reported_conflicts)]
 844
 845     reported_conflicts  go to state 6
 846
 847
 848 state 5
 849
 850     8 reported_conflicts: 'a' .  ['a']
 851     9                   | 'a' .  ['a']
 852
 853     'a'       reduce using rule 8 (reported_conflicts)
 854     'a'       [reduce using rule 9 (reported_conflicts)]
 855     $default  reduce using rule 8 (reported_conflicts)
 856
 857
 858 state 6
 859
 860     1 start: resolved_conflict 'a' reported_conflicts . 'a'
 861
 862     'a'  shift, and go to state 7
 863
 864
 865 state 7
 866
 867     1 start: resolved_conflict 'a' reported_conflicts 'a' .
 868
 869     $default  reduce using rule 1 (start)
 870 ]])
 871
 872 AT_DATA([[input-keep.y]],
 873 [[%define lr.keep-unreachable-states
 874 ]])
 875 AT_CHECK([[cat input.y >> input-keep.y]])
 876
 877 AT_BISON_CHECK([[input-keep.y]], 0, [],
 878 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
 879 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
 880 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
 881 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
 882 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
 883 ]])
 884
 885 AT_CLEANUP
 886
 887
 888 ## ------------------------------------------------------------ ##
 889 ## Solved conflicts report for multiple reductions in a state.  ##
 890 ## ------------------------------------------------------------ ##
 891
 892 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
 893
 894 # Used to lose earlier solved conflict messages even within a single S/R/R.
 895
 896 AT_DATA([[input.y]],
 897 [[%left 'a'
 898 %right 'b'
 899 %right 'c'
 900 %right 'd'
 901 %%
 902 start:
 903     'a'
 904   | empty_a 'a'
 905   | 'b'
 906   | empty_b 'b'
 907   | 'c'
 908   | empty_c1 'c'
 909   | empty_c2 'c'
 910   | empty_c3 'c'
 911   ;
 912 empty_a: %prec 'a' ;
 913 empty_b: %prec 'b' ;
 914 empty_c1: %prec 'c' ;
 915 empty_c2: %prec 'c' ;
 916 empty_c3: %prec 'd' ;
 917 ]])
 918 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 919 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
 920 [[state 0
 921
 922     0 $accept: . start $end
 923     1 start: . 'a'
 924     2      | . empty_a 'a'
 925     3      | . 'b'
 926     4      | . empty_b 'b'
 927     5      | . 'c'
 928     6      | . empty_c1 'c'
 929     7      | . empty_c2 'c'
 930     8      | . empty_c3 'c'
 931     9 empty_a: .  ['a']
 932    10 empty_b: .  []
 933    11 empty_c1: .  []
 934    12 empty_c2: .  []
 935    13 empty_c3: .  ['c']
 936
 937     'b'  shift, and go to state 1
 938
 939     'c'       reduce using rule 13 (empty_c3)
 940     $default  reduce using rule 9 (empty_a)
 941
 942     start     go to state 2
 943     empty_a   go to state 3
 944     empty_b   go to state 4
 945     empty_c1  go to state 5
 946     empty_c2  go to state 6
 947     empty_c3  go to state 7
 948
 949     Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
 950     Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
 951     Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
 952     Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
 953     Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
 954
 955
 956 state 1
 957 ]])
 958
 959 AT_CLEANUP
 960
 961
 962 ## ------------------------------------------------------------ ##
 963 ## %nonassoc error actions for multiple reductions in a state.  ##
 964 ## ------------------------------------------------------------ ##
 965
 966 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
 967 # multiple reductions in a state.
 968
 969 # For a %nonassoc error action token, used to print the first remaining
 970 # reduction on that token without brackets.
 971
 972 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
 973
 974 AT_DATA([[input.y]],
 975 [[%nonassoc 'a' 'b' 'c'
 976 %%
 977 start:
 978     'a'
 979   | empty_a 'a'
 980   | 'b'
 981   | empty_b 'b'
 982   | 'c'
 983   | empty_c1 'c'
 984   | empty_c2 'c'
 985   | empty_c3 'c'
 986   ;
 987 empty_a: %prec 'a' ;
 988 empty_b: %prec 'b' ;
 989 empty_c1: %prec 'c' ;
 990 empty_c2: %prec 'c' ;
 991 empty_c3: %prec 'c' ;
 992 ]])
 993
 994 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
 995 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
 996 [[state 0
 997
 998     0 $accept: . start $end
 999     1 start: . 'a'
1000     2      | . empty_a 'a'
1001     3      | . 'b'
1002     4      | . empty_b 'b'
1003     5      | . 'c'
1004     6      | . empty_c1 'c'
1005     7      | . empty_c2 'c'
1006     8      | . empty_c3 'c'
1007     9 empty_a: .  []
1008    10 empty_b: .  []
1009    11 empty_c1: .  []
1010    12 empty_c2: .  ['c']
1011    13 empty_c3: .  ['c']
1012
1013     'a'  error (nonassociative)
1014     'b'  error (nonassociative)
1015     'c'  error (nonassociative)
1016
1017     'c'  [reduce using rule 12 (empty_c2)]
1018     'c'  [reduce using rule 13 (empty_c3)]
1019
1020     start     go to state 1
1021     empty_a   go to state 2
1022     empty_b   go to state 3
1023     empty_c1  go to state 4
1024     empty_c2  go to state 5
1025     empty_c3  go to state 6
1026
1027     Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1028     Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1029     Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1030
1031
1032 state 1
1033 ]])
1034 AT_CLEANUP