tests/conflicts.at

   1 # Exercising Bison on conflicts.                         -*- Autotest -*-
   2 # Copyright (C) 2002 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., 59 Temple Place - Suite 330, Boston, MA
  17 # 02111-1307, USA.
  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_CHECK([bison -o input.c input.y], 0, [],
  41 [[input.y:4.9: warning: rule never reduced because of 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
  58 #if STDC_HEADERS
  59 # include <stdlib.h>
  60 #endif
  61
  62 #define YYERROR_VERBOSE 1
  63 static void
  64 yyerror (const char *msg)
  65 {
  66   fprintf (stderr, "%s\n", msg);
  67   exit (1);
  68 }
  69
  70 /* The current argument. */
  71 static const char *input = NULL;
  72
  73 static int
  74 yylex (void)
  75 {
  76   /* No token stands for end of file. */
  77   if (input && *input)
  78     return *input++;
  79   else
  80     return 0;
  81 }
  82
  83 %}
  84
  85 %nonassoc '<' '>'
  86
  87 %%
  88 expr: expr '<' expr
  89     | expr '>' expr
  90     | '0'
  91     ;
  92 %%
  93 int
  94 main (int argc, const char *argv[])
  95 {
  96   if (argc > 1)
  97     input = argv[1];
  98   return yyparse ();
  99 }
 100 ]])
 101
 102 # Specify the output files to avoid problems on different file systems.
 103 AT_CHECK([bison -o input.c input.y])
 104 AT_COMPILE([input])
 105
 106 AT_PARSER_CHECK([./input '0<0'])
 107 # FIXME: This is an actual bug, but a new one, in the sense that
 108 # no one has ever spotted it!  The messages are *wrong*: there should
 109 # be nothing there, it should be expected eof.
 110 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
 111          [syntax error, unexpected '<', expecting '<' or '>'
 112 ])
 113
 114 AT_PARSER_CHECK([./input '0>0'])
 115 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
 116          [syntax error, unexpected '>', expecting '<' or '>'
 117 ])
 118
 119 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
 120          [syntax error, unexpected '>', expecting '<' or '>'
 121 ])
 122
 123 AT_CLEANUP
 124
 125
 126
 127 ## ------------------------- ##
 128 ## Unresolved SR Conflicts.  ##
 129 ## ------------------------- ##
 130
 131 AT_SETUP([Unresolved SR Conflicts])
 132
 133 AT_KEYWORDS([report])
 134
 135 AT_DATA([input.y],
 136 [[%token NUM OP
 137 %%
 138 exp: exp OP exp | NUM;
 139 ]])
 140
 141 AT_CHECK([bison -o input.c --report=all input.y], 0, [],
 142 [input.y: warning: 1 shift/reduce conflict
 143 ])
 144
 145 # Check the contents of the report.
 146 AT_CHECK([cat input.output], [],
 147 [[State 5 contains 1 shift/reduce conflict.
 148
 149
 150 Grammar
 151
 152     0 $accept: exp $end
 153
 154     1 exp: exp OP exp
 155     2    | NUM
 156
 157
 158 Terminals, with rules where they appear
 159
 160 $end (0) 0
 161 error (256)
 162 NUM (258) 2
 163 OP (259) 1
 164
 165
 166 Nonterminals, with rules where they appear
 167
 168 $accept (5)
 169     on left: 0
 170 exp (6)
 171     on left: 1 2, on right: 0 1
 172
 173
 174 state 0
 175
 176     0 $accept: . exp $end
 177     1 exp: . exp OP exp
 178     2    | . NUM
 179
 180     NUM  shift, and go to state 1
 181
 182     exp  go to state 2
 183
 184
 185 state 1
 186
 187     2 exp: NUM .
 188
 189     $default  reduce using rule 2 (exp)
 190
 191
 192 state 2
 193
 194     0 $accept: exp . $end
 195     1 exp: exp . OP exp
 196
 197     $end  shift, and go to state 3
 198     OP    shift, and go to state 4
 199
 200
 201 state 3
 202
 203     0 $accept: exp $end .
 204
 205     $default  accept
 206
 207
 208 state 4
 209
 210     1 exp: . exp OP exp
 211     1    | exp OP . exp
 212     2    | . NUM
 213
 214     NUM  shift, and go to state 1
 215
 216     exp  go to state 5
 217
 218
 219 state 5
 220
 221     1 exp: exp . OP exp  [$end, OP]
 222     1    | exp OP exp .  [$end, OP]
 223
 224     OP  shift, and go to state 4
 225
 226     OP        [reduce using rule 1 (exp)]
 227     $default  reduce using rule 1 (exp)
 228 ]])
 229
 230 AT_CLEANUP
 231
 232
 233
 234 ## ----------------------- ##
 235 ## Resolved SR Conflicts.  ##
 236 ## ----------------------- ##
 237
 238 AT_SETUP([Resolved SR Conflicts])
 239
 240 AT_KEYWORDS([report])
 241
 242 AT_DATA([input.y],
 243 [[%token NUM OP
 244 %left OP
 245 %%
 246 exp: exp OP exp | NUM;
 247 ]])
 248
 249 AT_CHECK([bison -o input.c --report=all input.y])
 250
 251 # Check the contents of the report.
 252 AT_CHECK([cat input.output], [],
 253 [[Grammar
 254
 255     0 $accept: exp $end
 256
 257     1 exp: exp OP exp
 258     2    | NUM
 259
 260
 261 Terminals, with rules where they appear
 262
 263 $end (0) 0
 264 error (256)
 265 NUM (258) 2
 266 OP (259) 1
 267
 268
 269 Nonterminals, with rules where they appear
 270
 271 $accept (5)
 272     on left: 0
 273 exp (6)
 274     on left: 1 2, on right: 0 1
 275
 276
 277 state 0
 278
 279     0 $accept: . exp $end
 280     1 exp: . exp OP exp
 281     2    | . NUM
 282
 283     NUM  shift, and go to state 1
 284
 285     exp  go to state 2
 286
 287
 288 state 1
 289
 290     2 exp: NUM .
 291
 292     $default  reduce using rule 2 (exp)
 293
 294
 295 state 2
 296
 297     0 $accept: exp . $end
 298     1 exp: exp . OP exp
 299
 300     $end  shift, and go to state 3
 301     OP    shift, and go to state 4
 302
 303
 304 state 3
 305
 306     0 $accept: exp $end .
 307
 308     $default  accept
 309
 310
 311 state 4
 312
 313     1 exp: . exp OP exp
 314     1    | exp OP . exp
 315     2    | . NUM
 316
 317     NUM  shift, and go to state 1
 318
 319     exp  go to state 5
 320
 321
 322 state 5
 323
 324     1 exp: exp . OP exp  [$end, OP]
 325     1    | exp OP exp .  [$end, OP]
 326
 327     $default  reduce using rule 1 (exp)
 328
 329     Conflict between rule 1 and token OP resolved as reduce (%left OP).
 330 ]])
 331
 332 AT_CLEANUP
 333
 334
 335 ## -------------------------------- ##
 336 ## Defaulted Conflicted Reduction.  ##
 337 ## -------------------------------- ##
 338
 339 # When there are RR conflicts, some rules are disabled.  Usually it is
 340 # simply displayed as:
 341 #
 342 #    $end           reduce using rule 3 (num)
 343 #    $end           [reduce using rule 4 (id)]
 344 #
 345 # But when `reduce 3' is the default action, we'd produce:
 346 #
 347 #    $end           [reduce using rule 4 (id)]
 348 #    $default    reduce using rule 3 (num)
 349 #
 350 # In this precise case (a reduction is masked by the default
 351 # reduction), we make the `reduce 3' explicit:
 352 #
 353 #    $end           reduce using rule 3 (num)
 354 #    $end           [reduce using rule 4 (id)]
 355 #    $default    reduce using rule 3 (num)
 356 #
 357 # Maybe that's not the best display, but then, please propose something
 358 # else.
 359
 360 AT_SETUP([Defaulted Conflicted Reduction])
 361 AT_KEYWORDS([report])
 362
 363 AT_DATA([input.y],
 364 [[%%
 365 exp: num | id;
 366 num: '0';
 367 id : '0';
 368 %%
 369 ]])
 370
 371 AT_CHECK([bison -o input.c --report=all input.y], 0, [],
 372 [[input.y: warning: 1 reduce/reduce conflict
 373 input.y:4.6-8: warning: rule never reduced because of conflicts: id: '0'
 374 ]])
 375
 376 # Check the contents of the report.
 377 AT_CHECK([cat input.output], [],
 378 [[Rules never reduced
 379
 380     4 id: '0'
 381
 382
 383 State 1 contains 1 reduce/reduce conflict.
 384
 385
 386 Grammar
 387
 388     0 $accept: exp $end
 389
 390     1 exp: num
 391     2    | id
 392
 393     3 num: '0'
 394
 395     4 id: '0'
 396
 397
 398 Terminals, with rules where they appear
 399
 400 $end (0) 0
 401 '0' (48) 3 4
 402 error (256)
 403
 404
 405 Nonterminals, with rules where they appear
 406
 407 $accept (4)
 408     on left: 0
 409 exp (5)
 410     on left: 1 2, on right: 0
 411 num (6)
 412     on left: 3, on right: 1
 413 id (7)
 414     on left: 4, on right: 2
 415
 416
 417 state 0
 418
 419     0 $accept: . exp $end
 420     1 exp: . num
 421     2    | . id
 422     3 num: . '0'
 423     4 id: . '0'
 424
 425     '0'  shift, and go to state 1
 426
 427     exp  go to state 2
 428     num  go to state 3
 429     id   go to state 4
 430
 431
 432 state 1
 433
 434     3 num: '0' .  [$end]
 435     4 id: '0' .  [$end]
 436
 437     $end      reduce using rule 3 (num)
 438     $end      [reduce using rule 4 (id)]
 439     $default  reduce using rule 3 (num)
 440
 441
 442 state 2
 443
 444     0 $accept: exp . $end
 445
 446     $end  shift, and go to state 5
 447
 448
 449 state 3
 450
 451     1 exp: num .
 452
 453     $default  reduce using rule 1 (exp)
 454
 455
 456 state 4
 457
 458     2 exp: id .
 459
 460     $default  reduce using rule 2 (exp)
 461
 462
 463 state 5
 464
 465     0 $accept: exp $end .
 466
 467     $default  accept
 468 ]])
 469
 470 AT_CLEANUP
 471
 472
 473
 474
 475 ## -------------------- ##
 476 ## %expect not enough.  ##
 477 ## -------------------- ##
 478
 479 AT_SETUP([%expect not enough])
 480
 481 AT_DATA([input.y],
 482 [[%token NUM OP
 483 %expect 0
 484 %%
 485 exp: exp OP exp | NUM;
 486 ]])
 487
 488 AT_CHECK([bison -o input.c input.y], 1, [],
 489 [input.y: warning: 1 shift/reduce conflict
 490 input.y: expected 0 shift/reduce conflicts
 491 ])
 492 AT_CLEANUP
 493
 494
 495 ## --------------- ##
 496 ## %expect right.  ##
 497 ## --------------- ##
 498
 499 AT_SETUP([%expect right])
 500
 501 AT_DATA([input.y],
 502 [[%token NUM OP
 503 %expect 1
 504 %%
 505 exp: exp OP exp | NUM;
 506 ]])
 507
 508 AT_CHECK([bison -o input.c input.y])
 509 AT_CLEANUP
 510
 511
 512 ## ------------------ ##
 513 ## %expect too much.  ##
 514 ## ------------------ ##
 515
 516 AT_SETUP([%expect too much])
 517
 518 AT_DATA([input.y],
 519 [[%token NUM OP
 520 %expect 2
 521 %%
 522 exp: exp OP exp | NUM;
 523 ]])
 524
 525 AT_CHECK([bison -o input.c input.y], 1, [],
 526 [input.y: warning: 1 shift/reduce conflict
 527 input.y: expected 2 shift/reduce conflicts
 528 ])
 529 AT_CLEANUP