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1 # Exercising Bison on conflicts. -*- Autotest -*-
2
3 # Copyright (C) 2002-2005, 2007, 2009-2012 Free Software Foundation,
4 # 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 m4_pushdef([AT_NONASSOC_AND_EOF_CHECK],
98 [AT_BISON_CHECK([$1[ -o input.c input.y]])
99 AT_COMPILE([input])
100
101 m4_pushdef([AT_EXPECTING], [m4_if($2, [correct], [[, expecting $end]])])
102
103 AT_PARSER_CHECK([./input '0<0'])
104 AT_PARSER_CHECK([./input '0<0<0'], [1], [],
105 [syntax error, unexpected '<'AT_EXPECTING
106 ])
107
108 AT_PARSER_CHECK([./input '0>0'])
109 AT_PARSER_CHECK([./input '0>0>0'], [1], [],
110 [syntax error, unexpected '>'AT_EXPECTING
111 ])
112
113 AT_PARSER_CHECK([./input '0<0>0'], [1], [],
114 [syntax error, unexpected '>'AT_EXPECTING
115 ])
116
117 m4_popdef([AT_EXPECTING])])
118
119 # Expected token list is missing.
120 AT_NONASSOC_AND_EOF_CHECK([], [[incorrect]])
121
122 # We must disable default reductions in inconsistent states in order to
123 # have an explicit list of all expected tokens.
124 AT_NONASSOC_AND_EOF_CHECK([[-Dlr.default-reductions=consistent]],
125 [[correct]])
126
127 # lr.default-reductions=consistent happens to work for this test case.
128 # However, for other grammars, lookahead sets can be merged for
129 # different left contexts, so it is still possible to have an incorrect
130 # expected list. Canonical LR is almost a general solution (that is, it
131 # can fail only when %nonassoc is used), so make sure it gives the same
132 # result as above.
133 AT_NONASSOC_AND_EOF_CHECK([[-Dlr.type=canonical-lr]], [[correct]])
134
135 # parse.lac=full is a completely general solution that does not require
136 # any of the above sacrifices. Of course, it does not extend the
137 # language-recognition power of LALR to (IE)LR, but it does ensure that
138 # the reported list of expected tokens matches what the given parser
139 # would have accepted in place of the unexpected token.
140 AT_NONASSOC_AND_EOF_CHECK([[-Dparse.lac=full]], [[correct]])
141
142 m4_popdef([AT_NONASSOC_AND_EOF_CHECK])
143
144 AT_CLEANUP
145
146
147
148 ## -------------------------------------- ##
149 ## %error-verbose and consistent errors. ##
150 ## -------------------------------------- ##
151
152 AT_SETUP([[%error-verbose and consistent errors]])
153
154 m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [
155
156 AT_BISON_OPTION_PUSHDEFS([$1])
157
158 m4_pushdef([AT_YYLEX_PROTOTYPE],
159 [AT_SKEL_CC_IF([[int yylex (yy::parser::semantic_type *lvalp)]],
160 [[int yylex (YYSTYPE *lvalp)]])])
161
162 AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y],
163 [AT_SKEL_JAVA_IF([[
164
165 %code imports {
166 import java.io.IOException;
167 }]], [[
168
169 %code {]AT_SKEL_CC_IF([[
170 #include <cassert>
171 #include <string>]], [[
172 #include <assert.h>
173 #include <stdio.h>
174 void yyerror (char const *msg);]])[
175 ]AT_YYLEX_PROTOTYPE[;
176 #define USE(Var)
177 }
178
179 ]AT_SKEL_CC_IF([[%defines]], [[%define api.pure]])])[
180
181 ]$1[
182
183 %error-verbose
184
185 %%
186
187 ]$2[
188
189 ]AT_SKEL_JAVA_IF([[%code lexer {]], [[%%]])[
190
191 /*--------.
192 | yylex. |
193 `--------*/]AT_SKEL_JAVA_IF([[
194
195 public String input = "]$3[";
196 public int index = 0;
197 public int yylex ()
198 {
199 if (index < input.length ())
200 return input.charAt (index++);
201 else
202 return 0;
203 }
204 public Object getLVal ()
205 {
206 return new Integer(1);
207 }]], [[
208
209 ]AT_YYLEX_PROTOTYPE[
210 {
211 static char const *input = "]$3[";
212 *lvalp = 1;
213 return *input++;
214 }]])[
215
216 /*----------.
217 | yyerror. |
218 `----------*/]AT_SKEL_JAVA_IF([[
219
220 public void yyerror (String msg)
221 {
222 System.err.println (msg);
223 }
224
225 };
226
227 %%]], [AT_SKEL_CC_IF([[
228
229 void
230 yy::parser::error (const yy::location &, std::string const &msg)
231 {
232 std::cerr << msg << std::endl;
233 }]], [[
234
235 void
236 yyerror (char const *msg)
237 {
238 fprintf (stderr, "%s\n", msg);
239 }]])])[
240
241 /*-------.
242 | main. |
243 `-------*/]AT_SKEL_JAVA_IF([[
244
245 class input
246 {
247 public static void main (String args[]) throws IOException
248 {
249 YYParser p = new YYParser ();
250 p.parse ();
251 }
252 }]], [AT_SKEL_CC_IF([[
253
254 int
255 main (void)
256 {
257 yy::parser parser;
258 return parser.parse ();
259 }]], [[
260
261 int
262 main (void)
263 {
264 return yyparse ();
265 }]])])[
266 ]])
267
268 AT_FULL_COMPILE([[input]])
269
270 m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']],
271 $5, [a], [[, expecting 'a']],
272 $5, [b], [[, expecting 'b']])])
273
274 AT_SKEL_JAVA_IF([AT_JAVA_PARSER_CHECK([[input]], [[0]]],
275 [AT_PARSER_CHECK([[./input]], [[1]]]),
276 [[]],
277 [[syntax error, unexpected ]$4[]AT_EXPECTING[
278 ]])
279
280 m4_popdef([AT_EXPECTING])
281 m4_popdef([AT_YYLEX_PROTOTYPE])
282 AT_BISON_OPTION_POPDEFS
283
284 ])
285
286 m4_pushdef([AT_PREVIOUS_STATE_GRAMMAR],
287 [[%nonassoc 'a';
288
289 start: consistent-error-on-a-a 'a' ;
290
291 consistent-error-on-a-a:
292 'a' default-reduction
293 | 'a' default-reduction 'a'
294 | 'a' shift
295 ;
296
297 default-reduction: /*empty*/ ;
298 shift: 'b' ;
299
300 // Provide another context in which all rules are useful so that this
301 // test case looks a little more realistic.
302 start: 'b' consistent-error-on-a-a 'c' ;
303 ]])
304
305 m4_pushdef([AT_PREVIOUS_STATE_INPUT], [[a]])
306
307 # Unfortunately, no expected tokens are reported even though 'b' can be
308 # accepted. Nevertheless, the main point of this test is to make sure
309 # that at least the unexpected token is reported. In a previous version
310 # of Bison, it wasn't reported because the error is detected in a
311 # consistent state with an error action, and that case always triggered
312 # the simple "syntax error" message.
313 #
314 # The point isn't to test IELR here, but state merging happens to
315 # complicate this example.
316 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr]],
317 [AT_PREVIOUS_STATE_GRAMMAR],
318 [AT_PREVIOUS_STATE_INPUT],
319 [[$end]], [[none]])
320 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
321 %glr-parser]],
322 [AT_PREVIOUS_STATE_GRAMMAR],
323 [AT_PREVIOUS_STATE_INPUT],
324 [[$end]], [[none]])
325 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
326 %language "c++"]],
327 [AT_PREVIOUS_STATE_GRAMMAR],
328 [AT_PREVIOUS_STATE_INPUT],
329 [[$end]], [[none]])
330 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
331 %language "java"]],
332 [AT_PREVIOUS_STATE_GRAMMAR],
333 [AT_PREVIOUS_STATE_INPUT],
334 [[end of input]], [[none]])
335
336 # Even canonical LR doesn't foresee the error for 'a'!
337 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
338 %define lr.default-reductions consistent]],
339 [AT_PREVIOUS_STATE_GRAMMAR],
340 [AT_PREVIOUS_STATE_INPUT],
341 [[$end]], [[ab]])
342 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
343 %define lr.default-reductions accepting]],
344 [AT_PREVIOUS_STATE_GRAMMAR],
345 [AT_PREVIOUS_STATE_INPUT],
346 [[$end]], [[ab]])
347 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
348 [AT_PREVIOUS_STATE_GRAMMAR],
349 [AT_PREVIOUS_STATE_INPUT],
350 [[$end]], [[ab]])
351
352 # Only LAC gets it right.
353 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr
354 %define parse.lac full]],
355 [AT_PREVIOUS_STATE_GRAMMAR],
356 [AT_PREVIOUS_STATE_INPUT],
357 [[$end]], [[b]])
358 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr
359 %define parse.lac full]],
360 [AT_PREVIOUS_STATE_GRAMMAR],
361 [AT_PREVIOUS_STATE_INPUT],
362 [[$end]], [[b]])
363
364 m4_popdef([AT_PREVIOUS_STATE_GRAMMAR])
365 m4_popdef([AT_PREVIOUS_STATE_INPUT])
366
367 m4_pushdef([AT_USER_ACTION_GRAMMAR],
368 [[%nonassoc 'a';
369
370 // If $$ = 0 here, then we know that the 'a' destructor is being invoked
371 // incorrectly for the 'b' set in the semantic action below. All 'a'
372 // tokens are returned by yylex, which sets $$ = 1.
373 %destructor {
374 if (!$$)
375 fprintf (stderr, "Wrong destructor.\n");
376 } 'a';
377
378 // Rather than depend on an inconsistent state to induce reading a
379 // lookahead as in the previous grammar, just assign the lookahead in a
380 // semantic action. That lookahead isn't needed before either error
381 // action is encountered. In a previous version of Bison, this was a
382 // problem as it meant yychar was not translated into yytoken before
383 // either error action. The second error action thus invoked a
384 // destructor that it selected according to the incorrect yytoken. The
385 // first error action would have reported an incorrect unexpected token
386 // except that, due to the bug described in the previous grammar, the
387 // unexpected token was not reported at all.
388 start: error-reduce consistent-error 'a' { USE ($][3); } ;
389
390 error-reduce:
391 'a' 'a' consistent-reduction consistent-error 'a'
392 { USE (($][1, $][2, $][5)); }
393 | 'a' error
394 { USE ($][1); }
395 ;
396
397 consistent-reduction: /*empty*/ {
398 assert (yychar == ]AT_SKEL_CC_IF([[yyempty_]], [[YYEMPTY]])[);
399 yylval = 0;
400 yychar = 'b';
401 } ;
402
403 consistent-error:
404 'a' { USE ($][1); }
405 | /*empty*/ %prec 'a'
406 ;
407
408 // Provide another context in which all rules are useful so that this
409 // test case looks a little more realistic.
410 start: 'b' consistent-error 'b' ;
411 ]])
412 m4_pushdef([AT_USER_ACTION_INPUT], [[aa]])
413
414 AT_CONSISTENT_ERRORS_CHECK([[]],
415 [AT_USER_ACTION_GRAMMAR],
416 [AT_USER_ACTION_INPUT],
417 [['b']], [[none]])
418 AT_CONSISTENT_ERRORS_CHECK([[%glr-parser]],
419 [AT_USER_ACTION_GRAMMAR],
420 [AT_USER_ACTION_INPUT],
421 [['b']], [[none]])
422 AT_CONSISTENT_ERRORS_CHECK([[%language "c++"]],
423 [AT_USER_ACTION_GRAMMAR],
424 [AT_USER_ACTION_INPUT],
425 [['b']], [[none]])
426 # No Java test because yychar cannot be manipulated by users.
427
428 AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions consistent]],
429 [AT_USER_ACTION_GRAMMAR],
430 [AT_USER_ACTION_INPUT],
431 [['b']], [[none]])
432
433 # Canonical LR doesn't foresee the error for 'a'!
434 AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions accepting]],
435 [AT_USER_ACTION_GRAMMAR],
436 [AT_USER_ACTION_INPUT],
437 [[$end]], [[a]])
438 AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]],
439 [AT_USER_ACTION_GRAMMAR],
440 [AT_USER_ACTION_INPUT],
441 [[$end]], [[a]])
442
443 AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full]],
444 [AT_USER_ACTION_GRAMMAR],
445 [AT_USER_ACTION_INPUT],
446 [['b']], [[none]])
447 AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full
448 %define lr.default-reductions accepting]],
449 [AT_USER_ACTION_GRAMMAR],
450 [AT_USER_ACTION_INPUT],
451 [[$end]], [[none]])
452
453 m4_popdef([AT_USER_ACTION_GRAMMAR])
454 m4_popdef([AT_USER_ACTION_INPUT])
455
456 m4_popdef([AT_CONSISTENT_ERRORS_CHECK])
457
458 AT_CLEANUP
459
460
461
462 ## ------------------------------------------------------- ##
463 ## LAC: %nonassoc requires splitting canonical LR states. ##
464 ## ------------------------------------------------------- ##
465
466 # This test case demonstrates that, when %nonassoc is used, canonical
467 # LR(1) parser table construction followed by conflict resolution
468 # without further state splitting is not always sufficient to produce a
469 # parser that can detect all syntax errors as soon as possible on one
470 # token of lookahead. However, LAC solves the problem completely even
471 # with minimal LR parser tables.
472
473 AT_SETUP([[LAC: %nonassoc requires splitting canonical LR states]])
474
475 AT_DATA_GRAMMAR([[input.y]],
476 [[%code {
477 #include <stdio.h>
478 void yyerror (char const *);
479 int yylex (void);
480 }
481
482 %error-verbose
483 %nonassoc 'a'
484
485 %%
486
487 start:
488 'a' problem 'a' // First context.
489 | 'b' problem 'b' // Second context.
490 | 'c' reduce-nonassoc // Just makes reduce-nonassoc useful.
491 ;
492
493 problem:
494 look reduce-nonassoc
495 | look 'a'
496 | look 'b'
497 ;
498
499 // For the state reached after shifting the 'a' in these productions,
500 // lookahead sets are the same in both the first and second contexts.
501 // Thus, canonical LR reuses the same state for both contexts. However,
502 // the lookahead 'a' for the reduction "look: 'a'" later becomes an
503 // error action only in the first context. In order to immediately
504 // detect the syntax error on 'a' here for only the first context, this
505 // canonical LR state would have to be split into two states, and the
506 // 'a' lookahead would have to be removed from only one of the states.
507 look:
508 'a' // Reduction lookahead set is always ['a', 'b'].
509 | 'a' 'b'
510 | 'a' 'c' // 'c' is forgotten as an expected token.
511 ;
512
513 reduce-nonassoc: %prec 'a';
514
515 %%
516
517 void
518 yyerror (char const *msg)
519 {
520 fprintf (stderr, "%s\n", msg);
521 }
522
523 int
524 yylex (void)
525 {
526 char const *input = "aaa";
527 return *input++;
528 }
529
530 int
531 main (void)
532 {
533 return yyparse ();
534 }
535 ]])
536
537 # Show canonical LR's failure.
538 AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]],
539 [[0]], [[]],
540 [[input.y: conflicts: 2 shift/reduce
541 ]])
542 AT_COMPILE([[input]])
543 AT_PARSER_CHECK([[./input]], [[1]], [[]],
544 [[syntax error, unexpected 'a', expecting 'b'
545 ]])
546
547 # It's corrected by LAC.
548 AT_BISON_CHECK([[-Dlr.type=canonical-lr -Dparse.lac=full \
549 -o input.c input.y]], [[0]], [[]],
550 [[input.y: conflicts: 2 shift/reduce
551 ]])
552 AT_COMPILE([[input]])
553 AT_PARSER_CHECK([[./input]], [[1]], [[]],
554 [[syntax error, unexpected 'a', expecting 'b' or 'c'
555 ]])
556
557 # IELR is sufficient when LAC is used.
558 AT_BISON_CHECK([[-Dlr.type=ielr -Dparse.lac=full -o input.c input.y]],
559 [[0]], [[]],
560 [[input.y: conflicts: 2 shift/reduce
561 ]])
562 AT_COMPILE([[input]])
563 AT_PARSER_CHECK([[./input]], [[1]], [[]],
564 [[syntax error, unexpected 'a', expecting 'b' or 'c'
565 ]])
566
567 AT_CLEANUP
568
569 ## ------------------------- ##
570 ## Unresolved SR Conflicts. ##
571 ## ------------------------- ##
572
573 AT_SETUP([Unresolved SR Conflicts])
574
575 AT_KEYWORDS([report])
576
577 AT_DATA([input.y],
578 [[%token NUM OP
579 %%
580 exp: exp OP exp | NUM;
581 ]])
582
583 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
584 [input.y: conflicts: 1 shift/reduce
585 ])
586
587 # Check the contents of the report.
588 AT_CHECK([cat input.output], [],
589 [[State 5 conflicts: 1 shift/reduce
590
591
592 Grammar
593
594 0 $accept: exp $end
595
596 1 exp: exp OP exp
597 2 | NUM
598
599
600 Terminals, with rules where they appear
601
602 $end (0) 0
603 error (256)
604 NUM (258) 2
605 OP (259) 1
606
607
608 Nonterminals, with rules where they appear
609
610 $accept (5)
611 on left: 0
612 exp (6)
613 on left: 1 2, on right: 0 1
614
615
616 state 0
617
618 0 $accept: . exp $end
619 1 exp: . exp OP exp
620 2 | . NUM
621
622 NUM shift, and go to state 1
623
624 exp go to state 2
625
626
627 state 1
628
629 2 exp: NUM .
630
631 $default reduce using rule 2 (exp)
632
633
634 state 2
635
636 0 $accept: exp . $end
637 1 exp: exp . OP exp
638
639 $end shift, and go to state 3
640 OP shift, and go to state 4
641
642
643 state 3
644
645 0 $accept: exp $end .
646
647 $default accept
648
649
650 state 4
651
652 1 exp: . exp OP exp
653 1 | exp OP . exp
654 2 | . NUM
655
656 NUM shift, and go to state 1
657
658 exp go to state 5
659
660
661 state 5
662
663 1 exp: exp . OP exp
664 1 | exp OP exp . [$end, OP]
665
666 OP shift, and go to state 4
667
668 OP [reduce using rule 1 (exp)]
669 $default reduce using rule 1 (exp)
670 ]])
671
672 AT_CLEANUP
673
674
675
676 ## ----------------------- ##
677 ## Resolved SR Conflicts. ##
678 ## ----------------------- ##
679
680 AT_SETUP([Resolved SR Conflicts])
681
682 AT_KEYWORDS([report])
683
684 AT_DATA([input.y],
685 [[%token NUM OP
686 %left OP
687 %%
688 exp: exp OP exp | NUM;
689 ]])
690
691 AT_BISON_CHECK([-o input.c --report=all input.y])
692
693 # Check the contents of the report.
694 AT_CHECK([cat input.output], [],
695 [[Grammar
696
697 0 $accept: exp $end
698
699 1 exp: exp OP exp
700 2 | NUM
701
702
703 Terminals, with rules where they appear
704
705 $end (0) 0
706 error (256)
707 NUM (258) 2
708 OP (259) 1
709
710
711 Nonterminals, with rules where they appear
712
713 $accept (5)
714 on left: 0
715 exp (6)
716 on left: 1 2, on right: 0 1
717
718
719 state 0
720
721 0 $accept: . exp $end
722 1 exp: . exp OP exp
723 2 | . NUM
724
725 NUM shift, and go to state 1
726
727 exp go to state 2
728
729
730 state 1
731
732 2 exp: NUM .
733
734 $default reduce using rule 2 (exp)
735
736
737 state 2
738
739 0 $accept: exp . $end
740 1 exp: exp . OP exp
741
742 $end shift, and go to state 3
743 OP shift, and go to state 4
744
745
746 state 3
747
748 0 $accept: exp $end .
749
750 $default accept
751
752
753 state 4
754
755 1 exp: . exp OP exp
756 1 | exp OP . exp
757 2 | . NUM
758
759 NUM shift, and go to state 1
760
761 exp go to state 5
762
763
764 state 5
765
766 1 exp: exp . OP exp
767 1 | exp OP exp . [$end, OP]
768
769 $default reduce using rule 1 (exp)
770
771 Conflict between rule 1 and token OP resolved as reduce (%left OP).
772 ]])
773
774 AT_CLEANUP
775
776
777 ## -------------------------------- ##
778 ## Defaulted Conflicted Reduction. ##
779 ## -------------------------------- ##
780
781 # When there are RR conflicts, some rules are disabled. Usually it is
782 # simply displayed as:
783 #
784 # $end reduce using rule 3 (num)
785 # $end [reduce using rule 4 (id)]
786 #
787 # But when `reduce 3' is the default action, we'd produce:
788 #
789 # $end [reduce using rule 4 (id)]
790 # $default reduce using rule 3 (num)
791 #
792 # In this precise case (a reduction is masked by the default
793 # reduction), we make the `reduce 3' explicit:
794 #
795 # $end reduce using rule 3 (num)
796 # $end [reduce using rule 4 (id)]
797 # $default reduce using rule 3 (num)
798 #
799 # Maybe that's not the best display, but then, please propose something
800 # else.
801
802 AT_SETUP([Defaulted Conflicted Reduction])
803 AT_KEYWORDS([report])
804
805 AT_DATA([input.y],
806 [[%%
807 exp: num | id;
808 num: '0';
809 id : '0';
810 %%
811 ]])
812
813 AT_BISON_CHECK([-o input.c --report=all input.y], 0, [],
814 [[input.y: conflicts: 1 reduce/reduce
815 input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0'
816 ]])
817
818 # Check the contents of the report.
819 AT_CHECK([cat input.output], [],
820 [[Rules useless in parser due to conflicts
821
822 4 id: '0'
823
824
825 State 1 conflicts: 1 reduce/reduce
826
827
828 Grammar
829
830 0 $accept: exp $end
831
832 1 exp: num
833 2 | id
834
835 3 num: '0'
836
837 4 id: '0'
838
839
840 Terminals, with rules where they appear
841
842 $end (0) 0
843 '0' (48) 3 4
844 error (256)
845
846
847 Nonterminals, with rules where they appear
848
849 $accept (4)
850 on left: 0
851 exp (5)
852 on left: 1 2, on right: 0
853 num (6)
854 on left: 3, on right: 1
855 id (7)
856 on left: 4, on right: 2
857
858
859 state 0
860
861 0 $accept: . exp $end
862 1 exp: . num
863 2 | . id
864 3 num: . '0'
865 4 id: . '0'
866
867 '0' shift, and go to state 1
868
869 exp go to state 2
870 num go to state 3
871 id go to state 4
872
873
874 state 1
875
876 3 num: '0' . [$end]
877 4 id: '0' . [$end]
878
879 $end reduce using rule 3 (num)
880 $end [reduce using rule 4 (id)]
881 $default reduce using rule 3 (num)
882
883
884 state 2
885
886 0 $accept: exp . $end
887
888 $end shift, and go to state 5
889
890
891 state 3
892
893 1 exp: num .
894
895 $default reduce using rule 1 (exp)
896
897
898 state 4
899
900 2 exp: id .
901
902 $default reduce using rule 2 (exp)
903
904
905 state 5
906
907 0 $accept: exp $end .
908
909 $default accept
910 ]])
911
912 AT_CLEANUP
913
914
915
916
917 ## -------------------- ##
918 ## %expect not enough. ##
919 ## -------------------- ##
920
921 AT_SETUP([%expect not enough])
922
923 AT_DATA([input.y],
924 [[%token NUM OP
925 %expect 0
926 %%
927 exp: exp OP exp | NUM;
928 ]])
929
930 AT_BISON_CHECK([-o input.c input.y], 1, [],
931 [input.y: conflicts: 1 shift/reduce
932 input.y: expected 0 shift/reduce conflicts
933 ])
934 AT_CLEANUP
935
936
937 ## --------------- ##
938 ## %expect right. ##
939 ## --------------- ##
940
941 AT_SETUP([%expect right])
942
943 AT_DATA([input.y],
944 [[%token NUM OP
945 %expect 1
946 %%
947 exp: exp OP exp | NUM;
948 ]])
949
950 AT_BISON_CHECK([-o input.c input.y])
951 AT_CLEANUP
952
953
954 ## ------------------ ##
955 ## %expect too much. ##
956 ## ------------------ ##
957
958 AT_SETUP([%expect too much])
959
960 AT_DATA([input.y],
961 [[%token NUM OP
962 %expect 2
963 %%
964 exp: exp OP exp | NUM;
965 ]])
966
967 AT_BISON_CHECK([-o input.c input.y], 1, [],
968 [input.y: conflicts: 1 shift/reduce
969 input.y: expected 2 shift/reduce conflicts
970 ])
971 AT_CLEANUP
972
973
974 ## ------------------------------- ##
975 ## %expect with reduce conflicts. ##
976 ## ------------------------------- ##
977
978 AT_SETUP([%expect with reduce conflicts])
979
980 AT_DATA([input.y],
981 [[%expect 0
982 %%
983 program: a 'a' | a a;
984 a: 'a';
985 ]])
986
987 AT_BISON_CHECK([-o input.c input.y], 1, [],
988 [input.y: conflicts: 1 reduce/reduce
989 input.y: expected 0 reduce/reduce conflicts
990 ])
991 AT_CLEANUP
992
993
994 ## ------------------------- ##
995 ## %prec with user strings. ##
996 ## ------------------------- ##
997
998 AT_SETUP([%prec with user string])
999
1000 AT_DATA([[input.y]],
1001 [[%%
1002 exp:
1003 "foo" %prec "foo"
1004 ;
1005 ]])
1006
1007 AT_BISON_CHECK([-o input.c input.y])
1008 AT_CLEANUP
1009
1010
1011 ## -------------------------------- ##
1012 ## %no-default-prec without %prec. ##
1013 ## -------------------------------- ##
1014
1015 AT_SETUP([%no-default-prec without %prec])
1016
1017 AT_DATA([[input.y]],
1018 [[%left '+'
1019 %left '*'
1020
1021 %%
1022
1023 %no-default-prec;
1024
1025 e: e '+' e
1026 | e '*' e
1027 | '0'
1028 ;
1029 ]])
1030
1031 AT_BISON_CHECK([-o input.c input.y], 0, [],
1032 [[input.y: conflicts: 4 shift/reduce
1033 ]])
1034 AT_CLEANUP
1035
1036
1037 ## ----------------------------- ##
1038 ## %no-default-prec with %prec. ##
1039 ## ----------------------------- ##
1040
1041 AT_SETUP([%no-default-prec with %prec])
1042
1043 AT_DATA([[input.y]],
1044 [[%left '+'
1045 %left '*'
1046
1047 %%
1048
1049 %no-default-prec;
1050
1051 e: e '+' e %prec '+'
1052 | e '*' e %prec '*'
1053 | '0'
1054 ;
1055 ]])
1056
1057 AT_BISON_CHECK([-o input.c input.y])
1058 AT_CLEANUP
1059
1060
1061 ## --------------- ##
1062 ## %default-prec. ##
1063 ## --------------- ##
1064
1065 AT_SETUP([%default-prec])
1066
1067 AT_DATA([[input.y]],
1068 [[%left '+'
1069 %left '*'
1070
1071 %%
1072
1073 %default-prec;
1074
1075 e: e '+' e
1076 | e '*' e
1077 | '0'
1078 ;
1079 ]])
1080
1081 AT_BISON_CHECK([-o input.c input.y])
1082 AT_CLEANUP
1083
1084
1085 ## ---------------------------------------------- ##
1086 ## Unreachable States After Conflict Resolution. ##
1087 ## ---------------------------------------------- ##
1088
1089 AT_SETUP([[Unreachable States After Conflict Resolution]])
1090
1091 # If conflict resolution makes states unreachable, remove those states, report
1092 # rules that are then unused, and don't report conflicts in those states. Test
1093 # what happens when a nonterminal becomes useless as a result of state removal
1094 # since that causes lalr.o's goto map to be rewritten.
1095
1096 AT_DATA([[input.y]],
1097 [[%output "input.c"
1098 %left 'a'
1099
1100 %%
1101
1102 start: resolved_conflict 'a' reported_conflicts 'a' ;
1103
1104 /* S/R conflict resolved as reduce, so the state with item
1105 * (resolved_conflict: 'a' . unreachable1) and all it transition successors are
1106 * unreachable, and the associated production is useless. */
1107 resolved_conflict:
1108 'a' unreachable1
1109 | %prec 'a'
1110 ;
1111
1112 /* S/R conflict that need not be reported since it is unreachable because of
1113 * the previous conflict resolution. Nonterminal unreachable1 and all its
1114 * productions are useless. */
1115 unreachable1:
1116 'a' unreachable2
1117 |
1118 ;
1119
1120 /* Likewise for a R/R conflict and nonterminal unreachable2. */
1121 unreachable2: | ;
1122
1123 /* Make sure remaining S/R and R/R conflicts are still reported correctly even
1124 * when their states are renumbered due to state removal. */
1125 reported_conflicts:
1126 'a'
1127 | 'a'
1128 |
1129 ;
1130
1131 ]])
1132
1133 AT_BISON_CHECK([[--report=all input.y]], 0, [],
1134 [[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce
1135 input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1
1136 input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2
1137 input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
1138 input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1139 input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1140 input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
1141 input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
1142 ]])
1143
1144 AT_CHECK([[cat input.output]], 0,
1145 [[Rules useless in parser due to conflicts
1146
1147 2 resolved_conflict: 'a' unreachable1
1148
1149 4 unreachable1: 'a' unreachable2
1150 5 | /* empty */
1151
1152 6 unreachable2: /* empty */
1153 7 | /* empty */
1154
1155 9 reported_conflicts: 'a'
1156 10 | /* empty */
1157
1158
1159 State 4 conflicts: 1 shift/reduce
1160 State 5 conflicts: 1 reduce/reduce
1161
1162
1163 Grammar
1164
1165 0 $accept: start $end
1166
1167 1 start: resolved_conflict 'a' reported_conflicts 'a'
1168
1169 2 resolved_conflict: 'a' unreachable1
1170 3 | /* empty */
1171
1172 4 unreachable1: 'a' unreachable2
1173 5 | /* empty */
1174
1175 6 unreachable2: /* empty */
1176 7 | /* empty */
1177
1178 8 reported_conflicts: 'a'
1179 9 | 'a'
1180 10 | /* empty */
1181
1182
1183 Terminals, with rules where they appear
1184
1185 $end (0) 0
1186 'a' (97) 1 2 4 8 9
1187 error (256)
1188
1189
1190 Nonterminals, with rules where they appear
1191
1192 $accept (4)
1193 on left: 0
1194 start (5)
1195 on left: 1, on right: 0
1196 resolved_conflict (6)
1197 on left: 2 3, on right: 1
1198 unreachable1 (7)
1199 on left: 4 5, on right: 2
1200 unreachable2 (8)
1201 on left: 6 7, on right: 4
1202 reported_conflicts (9)
1203 on left: 8 9 10, on right: 1
1204
1205
1206 state 0
1207
1208 0 $accept: . start $end
1209 1 start: . resolved_conflict 'a' reported_conflicts 'a'
1210 2 resolved_conflict: . 'a' unreachable1
1211 3 | . ['a']
1212
1213 $default reduce using rule 3 (resolved_conflict)
1214
1215 start go to state 1
1216 resolved_conflict go to state 2
1217
1218 Conflict between rule 3 and token 'a' resolved as reduce (%left 'a').
1219
1220
1221 state 1
1222
1223 0 $accept: start . $end
1224
1225 $end shift, and go to state 3
1226
1227
1228 state 2
1229
1230 1 start: resolved_conflict . 'a' reported_conflicts 'a'
1231
1232 'a' shift, and go to state 4
1233
1234
1235 state 3
1236
1237 0 $accept: start $end .
1238
1239 $default accept
1240
1241
1242 state 4
1243
1244 1 start: resolved_conflict 'a' . reported_conflicts 'a'
1245 8 reported_conflicts: . 'a'
1246 9 | . 'a'
1247 10 | . ['a']
1248
1249 'a' shift, and go to state 5
1250
1251 'a' [reduce using rule 10 (reported_conflicts)]
1252
1253 reported_conflicts go to state 6
1254
1255
1256 state 5
1257
1258 8 reported_conflicts: 'a' . ['a']
1259 9 | 'a' . ['a']
1260
1261 'a' reduce using rule 8 (reported_conflicts)
1262 'a' [reduce using rule 9 (reported_conflicts)]
1263 $default reduce using rule 8 (reported_conflicts)
1264
1265
1266 state 6
1267
1268 1 start: resolved_conflict 'a' reported_conflicts . 'a'
1269
1270 'a' shift, and go to state 7
1271
1272
1273 state 7
1274
1275 1 start: resolved_conflict 'a' reported_conflicts 'a' .
1276
1277 $default reduce using rule 1 (start)
1278 ]])
1279
1280 AT_DATA([[input-keep.y]],
1281 [[%define lr.keep-unreachable-states
1282 ]])
1283 AT_CHECK([[cat input.y >> input-keep.y]])
1284
1285 AT_BISON_CHECK([[input-keep.y]], 0, [],
1286 [[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce
1287 input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */
1288 input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */
1289 input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a'
1290 input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */
1291 ]])
1292
1293 AT_CLEANUP
1294
1295
1296 ## ------------------------------------------------------------ ##
1297 ## Solved conflicts report for multiple reductions in a state. ##
1298 ## ------------------------------------------------------------ ##
1299
1300 AT_SETUP([[Solved conflicts report for multiple reductions in a state]])
1301
1302 # Used to lose earlier solved conflict messages even within a single S/R/R.
1303
1304 AT_DATA([[input.y]],
1305 [[%left 'a'
1306 %right 'b'
1307 %right 'c'
1308 %right 'd'
1309 %%
1310 start:
1311 'a'
1312 | empty_a 'a'
1313 | 'b'
1314 | empty_b 'b'
1315 | 'c'
1316 | empty_c1 'c'
1317 | empty_c2 'c'
1318 | empty_c3 'c'
1319 ;
1320 empty_a: %prec 'a' ;
1321 empty_b: %prec 'b' ;
1322 empty_c1: %prec 'c' ;
1323 empty_c2: %prec 'c' ;
1324 empty_c3: %prec 'd' ;
1325 ]])
1326 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1327 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
1328 [[state 0
1329
1330 0 $accept: . start $end
1331 1 start: . 'a'
1332 2 | . empty_a 'a'
1333 3 | . 'b'
1334 4 | . empty_b 'b'
1335 5 | . 'c'
1336 6 | . empty_c1 'c'
1337 7 | . empty_c2 'c'
1338 8 | . empty_c3 'c'
1339 9 empty_a: . ['a']
1340 10 empty_b: . []
1341 11 empty_c1: . []
1342 12 empty_c2: . []
1343 13 empty_c3: . ['c']
1344
1345 'b' shift, and go to state 1
1346
1347 'c' reduce using rule 13 (empty_c3)
1348 $default reduce using rule 9 (empty_a)
1349
1350 start go to state 2
1351 empty_a go to state 3
1352 empty_b go to state 4
1353 empty_c1 go to state 5
1354 empty_c2 go to state 6
1355 empty_c3 go to state 7
1356
1357 Conflict between rule 9 and token 'a' resolved as reduce (%left 'a').
1358 Conflict between rule 10 and token 'b' resolved as shift (%right 'b').
1359 Conflict between rule 11 and token 'c' resolved as shift (%right 'c').
1360 Conflict between rule 12 and token 'c' resolved as shift (%right 'c').
1361 Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd').
1362
1363
1364 state 1
1365 ]])
1366
1367 AT_CLEANUP
1368
1369
1370 ## ------------------------------------------------------------ ##
1371 ## %nonassoc error actions for multiple reductions in a state. ##
1372 ## ------------------------------------------------------------ ##
1373
1374 # Used to abort when trying to resolve conflicts as %nonassoc error actions for
1375 # multiple reductions in a state.
1376
1377 # For a %nonassoc error action token, used to print the first remaining
1378 # reduction on that token without brackets.
1379
1380 AT_SETUP([[%nonassoc error actions for multiple reductions in a state]])
1381
1382 AT_DATA([[input.y]],
1383 [[%nonassoc 'a' 'b' 'c'
1384 %%
1385 start:
1386 'a'
1387 | empty_a 'a'
1388 | 'b'
1389 | empty_b 'b'
1390 | 'c'
1391 | empty_c1 'c'
1392 | empty_c2 'c'
1393 | empty_c3 'c'
1394 ;
1395 empty_a: %prec 'a' ;
1396 empty_b: %prec 'b' ;
1397 empty_c1: %prec 'c' ;
1398 empty_c2: %prec 'c' ;
1399 empty_c3: %prec 'c' ;
1400 ]])
1401
1402 AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
1403 AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0,
1404 [[state 0
1405
1406 0 $accept: . start $end
1407 1 start: . 'a'
1408 2 | . empty_a 'a'
1409 3 | . 'b'
1410 4 | . empty_b 'b'
1411 5 | . 'c'
1412 6 | . empty_c1 'c'
1413 7 | . empty_c2 'c'
1414 8 | . empty_c3 'c'
1415 9 empty_a: . []
1416 10 empty_b: . []
1417 11 empty_c1: . []
1418 12 empty_c2: . ['c']
1419 13 empty_c3: . ['c']
1420
1421 'a' error (nonassociative)
1422 'b' error (nonassociative)
1423 'c' error (nonassociative)
1424
1425 'c' [reduce using rule 12 (empty_c2)]
1426 'c' [reduce using rule 13 (empty_c3)]
1427
1428 start go to state 1
1429 empty_a go to state 2
1430 empty_b go to state 3
1431 empty_c1 go to state 4
1432 empty_c2 go to state 5
1433 empty_c3 go to state 6
1434
1435 Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a').
1436 Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b').
1437 Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c').
1438
1439
1440 state 1
1441 ]])
1442 AT_CLEANUP
1443
1444
1445 ## --------------------------------- ##
1446 ## -W versus %expect and %expect-rr ##
1447 ## --------------------------------- ##
1448
1449 AT_SETUP([[-W versus %expect and %expect-rr]])
1450
1451 AT_DATA([[sr-rr.y]],
1452 [[%glr-parser
1453 %%
1454 start: 'a' | A 'a' | B 'a' ;
1455 A: ;
1456 B: ;
1457 ]])
1458 AT_DATA([[sr.y]],
1459 [[%glr-parser
1460 %%
1461 start: 'a' | A 'a' ;
1462 A: ;
1463 ]])
1464 AT_DATA([[rr.y]],
1465 [[%glr-parser
1466 %%
1467 start: A | B ;
1468 A: ;
1469 B: ;
1470 ]])
1471
1472 AT_BISON_CHECK([[sr-rr.y]], [[0]], [[]],
1473 [[sr-rr.y: conflicts: 1 shift/reduce, 1 reduce/reduce
1474 ]])
1475 AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]],
1476 [[sr-rr.y: conflicts: 1 reduce/reduce
1477 ]])
1478 AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]],
1479 [[sr-rr.y: conflicts: 1 shift/reduce
1480 ]])
1481
1482 [for gram in sr-rr sr rr; do
1483 for sr_exp_i in '' 0 1 2; do
1484 for rr_exp_i in '' 0 1 2; do
1485 test -z "$sr_exp_i" && test -z "$rr_exp_i" && continue
1486
1487 # Build grammar file.
1488 sr_exp=0
1489 rr_exp=0
1490 file=$gram
1491 directives=
1492 if test -n "$sr_exp_i"; then
1493 sr_exp=$sr_exp_i
1494 file=$file-expect-$sr_exp
1495 directives="%expect $sr_exp"
1496 fi
1497 if test -n "$rr_exp_i"; then
1498 rr_exp=$rr_exp_i
1499 file=$file-expect-rr-$rr_exp
1500 directives="$directives %expect-rr $rr_exp"
1501 fi
1502 file=$file.y
1503 echo "$directives" > $file
1504 cat $gram.y >> $file
1505
1506 # Count actual conflicts.
1507 conflicts=
1508 sr_count=0
1509 rr_count=0
1510 if test $gram = sr || test $gram = sr-rr; then
1511 conflicts="1 shift/reduce"
1512 sr_count=1
1513 fi
1514 if test $gram = rr || test $gram = sr-rr; then
1515 if test -n "$conflicts"; then
1516 conflicts="$conflicts, "
1517 fi
1518 conflicts="${conflicts}1 reduce/reduce"
1519 rr_count=1
1520 fi
1521
1522 # Run tests.
1523 if test $sr_count -eq $sr_exp && test $rr_count -eq $rr_exp; then
1524 ]AT_BISON_CHECK([[-Wnone $file]])[
1525 ]AT_BISON_CHECK([[-Werror $file]])[
1526 else
1527 echo "$file: conflicts: $conflicts" > experr
1528 if test $sr_count -ne $sr_exp; then
1529 if test $sr_exp -ne 1; then s=s; else s= ; fi
1530 echo "$file: expected $sr_exp shift/reduce conflict$s" >> experr
1531 fi
1532 if test $rr_count -ne $rr_exp; then
1533 if test $rr_exp -ne 1; then s=s; else s= ; fi
1534 echo "$file: expected $rr_exp reduce/reduce conflict$s" >> experr
1535 fi
1536 ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[
1537 ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[
1538 fi
1539 done
1540 done
1541 done]
1542
1543 AT_CLEANUP