tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2
   3 # Copyright (C) 2002, 2003 Free Software Foundation, Inc.
   4
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2, or (at your option)
   8 # any later version.
   9
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  18 # 02111-1307, USA.
  19
  20 AT_BANNER([[Conflicts.]])
  21
  22
  23 ## ---------------- ##
  24 ## S/R in initial.  ##
  25 ## ---------------- ##
  26
  27 # I once hacked Bison in such a way that it lost its reductions on the
  28 # initial state (because it was confusing it with the last state).  It
  29 # took me a while to strip down my failures to this simple case.  So
  30 # make sure it finds the s/r conflict below.
  31
  32 AT_SETUP([S/R in initial])
  33
  34 AT_DATA([[input.y]],
  35 [[%expect 1
  36 %%
  37 exp: e 'e';
  38 e: 'e' | /* Nothing. */;
  39 ]])
  40
  41 AT_CHECK([bison -o input.c input.y], 0, [],
  42 [[input.y:4.9: warning: rule never reduced because of conflicts: e: /* empty */
  43 ]])
  44
  45 AT_CLEANUP
  46
  47
  48 ## ------------------- ##
  49 ## %nonassoc and eof.  ##
  50 ## ------------------- ##
  51
  52 AT_SETUP([%nonassoc and eof])
  53
  54 AT_DATA_GRAMMAR([input.y],
  55 [[
  56 %{
  57 #include <stdio.h>
  58
  59 #if STDC_HEADERS
  60 # include <stdlib.h>
  61 #endif
  62
  63 #define YYERROR_VERBOSE 1
  64 static void
  65 yyerror (const char *msg)
  66 {
  67   fprintf (stderr, "%s\n", msg);
  68   exit (1);
  69 }
  70
  71 /* The current argument. */
  72 static const char *input = NULL;
  73
  74 static int
  75 yylex (void)
  76 {
  77   /* No token stands for end of file. */
  78   if (input && *input)
  79     return *input++;
  80   else
  81     return 0;
  82 }
  83
  84 %}
  85
  86 %nonassoc '<' '>'
  87
  88 %%
  89 expr: expr '<' expr
  90     | expr '>' expr
  91     | '0'
  92     ;
  93 %%
  94 int
  95 main (int argc, const char *argv[])
  96 {
  97   if (argc > 1)
  98     input = argv[1];
  99   return yyparse ();
 100 }
 101 ]])
 102
 103 # Specify the output files to avoid problems on different file systems.
 104 AT_CHECK([bison -o input.c input.y])
 105 AT_COMPILE([input])
 106
 107 AT_PARSER_CHECK([./input '0<0'])
 108 # FIXME: This is an actual bug, but a new one, in the sense that
 109 # no one has ever spotted it!  The messages are *wrong*: there should
 110 # be nothing there, it should be expected eof.
 111 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 112          [syntax error, unexpected '<', expecting '<' or '>'
 113 ])
 114
 115 AT_PARSER_CHECK([./input '0>0'])
 116 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 117          [syntax error, unexpected '>', expecting '<' or '>'
 118 ])
 119
 120 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 121          [syntax error, unexpected '>', expecting '<' or '>'
 122 ])
 123
 124 AT_CLEANUP
 125
 126
 127
 128 ## ------------------------- ##
 129 ## Unresolved SR Conflicts.  ##
 130 ## ------------------------- ##
 131
 132 AT_SETUP([Unresolved SR Conflicts])
 133
 134 AT_KEYWORDS([report])
 135
 136 AT_DATA([input.y],
 137 [[%token NUM OP
 138 %%
 139 exp: exp OP exp | NUM;
 140 ]])
 141
 142 AT_CHECK([bison -o input.c --report=all input.y], 0, [],
 143 [input.y: conflicts: 1 shift/reduce
 144 ])
 145
 146 # Check the contents of the report.
 147 AT_CHECK([cat input.output], [],
 148 [[State 5 conflicts: 1 shift/reduce
 149
 150
 151 Grammar
 152
 153     0 $accept: exp $end
 154
 155     1 exp: exp OP exp
 156     2    | NUM
 157
 158
 159 Terminals, with rules where they appear
 160
 161 $end (0) 0
 162 error (256)
 163 NUM (258) 2
 164 OP (259) 1
 165
 166
 167 Nonterminals, with rules where they appear
 168
 169 $accept (5)
 170     on left: 0
 171 exp (6)
 172     on left: 1 2, on right: 0 1
 173
 174
 175 state 0
 176
 177     0 $accept: . exp $end
 178     1 exp: . exp OP exp
 179     2    | . NUM
 180
 181     NUM  shift, and go to state 1
 182
 183     exp  go to state 2
 184
 185
 186 state 1
 187
 188     2 exp: NUM .
 189
 190     $default  reduce using rule 2 (exp)
 191
 192
 193 state 2
 194
 195     0 $accept: exp . $end
 196     1 exp: exp . OP exp
 197
 198     $end  shift, and go to state 3
 199     OP    shift, and go to state 4
 200
 201
 202 state 3
 203
 204     0 $accept: exp $end .
 205
 206     $default  accept
 207
 208
 209 state 4
 210
 211     1 exp: . exp OP exp
 212     1    | exp OP . exp
 213     2    | . NUM
 214
 215     NUM  shift, and go to state 1
 216
 217     exp  go to state 5
 218
 219
 220 state 5
 221
 222     1 exp: exp . OP exp  [$end, OP]
 223     1    | exp OP exp .  [$end, OP]
 224
 225     OP  shift, and go to state 4
 226
 227     OP        [reduce using rule 1 (exp)]
 228     $default  reduce using rule 1 (exp)
 229 ]])
 230
 231 AT_CLEANUP
 232
 233
 234
 235 ## ----------------------- ##
 236 ## Resolved SR Conflicts.  ##
 237 ## ----------------------- ##
 238
 239 AT_SETUP([Resolved SR Conflicts])
 240
 241 AT_KEYWORDS([report])
 242
 243 AT_DATA([input.y],
 244 [[%token NUM OP
 245 %left OP
 246 %%
 247 exp: exp OP exp | NUM;
 248 ]])
 249
 250 AT_CHECK([bison -o input.c --report=all input.y])
 251
 252 # Check the contents of the report.
 253 AT_CHECK([cat input.output], [],
 254 [[Grammar
 255
 256     0 $accept: exp $end
 257
 258     1 exp: exp OP exp
 259     2    | NUM
 260
 261
 262 Terminals, with rules where they appear
 263
 264 $end (0) 0
 265 error (256)
 266 NUM (258) 2
 267 OP (259) 1
 268
 269
 270 Nonterminals, with rules where they appear
 271
 272 $accept (5)
 273     on left: 0
 274 exp (6)
 275     on left: 1 2, on right: 0 1
 276
 277
 278 state 0
 279
 280     0 $accept: . exp $end
 281     1 exp: . exp OP exp
 282     2    | . NUM
 283
 284     NUM  shift, and go to state 1
 285
 286     exp  go to state 2
 287
 288
 289 state 1
 290
 291     2 exp: NUM .
 292
 293     $default  reduce using rule 2 (exp)
 294
 295
 296 state 2
 297
 298     0 $accept: exp . $end
 299     1 exp: exp . OP exp
 300
 301     $end  shift, and go to state 3
 302     OP    shift, and go to state 4
 303
 304
 305 state 3
 306
 307     0 $accept: exp $end .
 308
 309     $default  accept
 310
 311
 312 state 4
 313
 314     1 exp: . exp OP exp
 315     1    | exp OP . exp
 316     2    | . NUM
 317
 318     NUM  shift, and go to state 1
 319
 320     exp  go to state 5
 321
 322
 323 state 5
 324
 325     1 exp: exp . OP exp  [$end, OP]
 326     1    | exp OP exp .  [$end, OP]
 327
 328     $default  reduce using rule 1 (exp)
 329
 330     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 331 ]])
 332
 333 AT_CLEANUP
 334
 335
 336 ## -------------------------------- ##
 337 ## Defaulted Conflicted Reduction.  ##
 338 ## -------------------------------- ##
 339
 340 # When there are RR conflicts, some rules are disabled.  Usually it is
 341 # simply displayed as:
 342 #
 343 #    $end           reduce using rule 3 (num)
 344 #    $end           [reduce using rule 4 (id)]
 345 #
 346 # But when `reduce 3' is the default action, we'd produce:
 347 #
 348 #    $end           [reduce using rule 4 (id)]
 349 #    $default    reduce using rule 3 (num)
 350 #
 351 # In this precise case (a reduction is masked by the default
 352 # reduction), we make the `reduce 3' explicit:
 353 #
 354 #    $end           reduce using rule 3 (num)
 355 #    $end           [reduce using rule 4 (id)]
 356 #    $default    reduce using rule 3 (num)
 357 #
 358 # Maybe that's not the best display, but then, please propose something
 359 # else.
 360
 361 AT_SETUP([Defaulted Conflicted Reduction])
 362 AT_KEYWORDS([report])
 363
 364 AT_DATA([input.y],
 365 [[%%
 366 exp: num | id;
 367 num: '0';
 368 id : '0';
 369 %%
 370 ]])
 371
 372 AT_CHECK([bison -o input.c --report=all input.y], 0, [],
 373 [[input.y: conflicts: 1 reduce/reduce
 374 input.y:4.6-8: warning: rule never reduced because of conflicts: id: '0'
 375 ]])
 376
 377 # Check the contents of the report.
 378 AT_CHECK([cat input.output], [],
 379 [[Rules never reduced
 380
 381     4 id: '0'
 382
 383
 384 State 1 conflicts: 1 reduce/reduce
 385
 386
 387 Grammar
 388
 389     0 $accept: exp $end
 390
 391     1 exp: num
 392     2    | id
 393
 394     3 num: '0'
 395
 396     4 id: '0'
 397
 398
 399 Terminals, with rules where they appear
 400
 401 $end (0) 0
 402 '0' (48) 3 4
 403 error (256)
 404
 405
 406 Nonterminals, with rules where they appear
 407
 408 $accept (4)
 409     on left: 0
 410 exp (5)
 411     on left: 1 2, on right: 0
 412 num (6)
 413     on left: 3, on right: 1
 414 id (7)
 415     on left: 4, on right: 2
 416
 417
 418 state 0
 419
 420     0 $accept: . exp $end
 421     1 exp: . num
 422     2    | . id
 423     3 num: . '0'
 424     4 id: . '0'
 425
 426     '0'  shift, and go to state 1
 427
 428     exp  go to state 2
 429     num  go to state 3
 430     id   go to state 4
 431
 432
 433 state 1
 434
 435     3 num: '0' .  [$end]
 436     4 id: '0' .  [$end]
 437
 438     $end      reduce using rule 3 (num)
 439     $end      [reduce using rule 4 (id)]
 440     $default  reduce using rule 3 (num)
 441
 442
 443 state 2
 444
 445     0 $accept: exp . $end
 446
 447     $end  shift, and go to state 5
 448
 449
 450 state 3
 451
 452     1 exp: num .
 453
 454     $default  reduce using rule 1 (exp)
 455
 456
 457 state 4
 458
 459     2 exp: id .
 460
 461     $default  reduce using rule 2 (exp)
 462
 463
 464 state 5
 465
 466     0 $accept: exp $end .
 467
 468     $default  accept
 469 ]])
 470
 471 AT_CLEANUP
 472
 473
 474
 475
 476 ## -------------------- ##
 477 ## %expect not enough.  ##
 478 ## -------------------- ##
 479
 480 AT_SETUP([%expect not enough])
 481
 482 AT_DATA([input.y],
 483 [[%token NUM OP
 484 %expect 0
 485 %%
 486 exp: exp OP exp | NUM;
 487 ]])
 488
 489 AT_CHECK([bison -o input.c input.y], 0, [],
 490 [input.y: conflicts: 1 shift/reduce
 491 input.y: warning: expected 0 shift/reduce conflicts
 492 ])
 493 AT_CLEANUP
 494
 495
 496 ## --------------- ##
 497 ## %expect right.  ##
 498 ## --------------- ##
 499
 500 AT_SETUP([%expect right])
 501
 502 AT_DATA([input.y],
 503 [[%token NUM OP
 504 %expect 1
 505 %%
 506 exp: exp OP exp | NUM;
 507 ]])
 508
 509 AT_CHECK([bison -o input.c input.y])
 510 AT_CLEANUP
 511
 512
 513 ## ------------------ ##
 514 ## %expect too much.  ##
 515 ## ------------------ ##
 516
 517 AT_SETUP([%expect too much])
 518
 519 AT_DATA([input.y],
 520 [[%token NUM OP
 521 %expect 2
 522 %%
 523 exp: exp OP exp | NUM;
 524 ]])
 525
 526 AT_CHECK([bison -o input.c input.y], 0, [],
 527 [input.y: conflicts: 1 shift/reduce
 528 input.y: warning: expected 2 shift/reduce conflicts
 529 ])
 530 AT_CLEANUP
 531
 532
 533 ## ------------------------------ ##
 534 ## %expect with reduce conflicts  ##
 535 ## ------------------------------ ##
 536
 537 AT_SETUP([%expect with reduce conflicts])
 538
 539 AT_DATA([input.y],
 540 [[%expect 0
 541 %%
 542 program: a 'a' | a a;
 543 a: 'a';
 544 ]])
 545
 546 AT_CHECK([bison -o input.c input.y], 0, [],
 547 [input.y: conflicts: 1 reduce/reduce
 548 input.y: warning: expected 0 reduce/reduce conflicts
 549 ])
 550 AT_CLEANUP