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1 %{/* Bison Grammar Parser -*- C -*-
2
3 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software
4 Foundation, Inc.
5
6 This file is part of Bison, the GNU Compiler Compiler.
7
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include <config.h>
22 #include "system.h"
23
24 #include "complain.h"
25 #include "conflicts.h"
26 #include "files.h"
27 #include "getargs.h"
28 #include "gram.h"
29 #include "muscle-tab.h"
30 #include "quotearg.h"
31 #include "reader.h"
32 #include "symlist.h"
33 #include "scan-gram.h"
34 #include "scan-code.h"
35
36 #define YYLLOC_DEFAULT(Current, Rhs, N) (Current) = lloc_default (Rhs, N)
37 static YYLTYPE lloc_default (YYLTYPE const *, int);
38
39 #define YY_LOCATION_PRINT(File, Loc) \
40 location_print (File, Loc)
41
42 static void version_check (location const *loc, char const *version);
43
44 /* Request detailed syntax error messages, and pass them to GRAM_ERROR.
45 FIXME: depends on the undocumented availability of YYLLOC. */
46 #undef yyerror
47 #define yyerror(Msg) \
48 gram_error (&yylloc, Msg)
49 static void gram_error (location const *, char const *);
50
51 static char const *char_name (char);
52
53 /** Add a lex-param or a parse-param.
54 *
55 * \param type \a lex_param or \a parse_param
56 * \param decl the formal argument
57 * \param loc the location in the source.
58 */
59 static void add_param (char const *type, char *decl, location loc);
60
61
62 static symbol_class current_class = unknown_sym;
63 static uniqstr current_type = NULL;
64 static symbol *current_lhs;
65 static location current_lhs_location;
66 static int current_prec = 0;
67
68 #define YYTYPE_INT16 int_fast16_t
69 #define YYTYPE_INT8 int_fast8_t
70 #define YYTYPE_UINT16 uint_fast16_t
71 #define YYTYPE_UINT8 uint_fast8_t
72 %}
73
74 %debug
75 %verbose
76 %defines
77 %locations
78 %pure-parser
79 %error-verbose
80 %name-prefix="gram_"
81 %expect 0
82
83 %initial-action
84 {
85 /* Bison's grammar can initial empty locations, hence a default
86 location is needed. */
87 boundary_set (&@$.start, current_file, 1, 1);
88 boundary_set (&@$.end, current_file, 1, 1);
89 }
90
91 %union
92 {
93 symbol *symbol;
94 symbol_list *list;
95 int integer;
96 char const *chars;
97 char *code;
98 assoc assoc;
99 uniqstr uniqstr;
100 unsigned char character;
101 };
102
103 /* Define the tokens together with their human representation. */
104 %token GRAM_EOF 0 "end of file"
105 %token STRING "string"
106 %token INT "integer"
107
108 %token PERCENT_TOKEN "%token"
109 %token PERCENT_NTERM "%nterm"
110
111 %token PERCENT_TYPE "%type"
112 %token PERCENT_DESTRUCTOR "%destructor"
113 %token PERCENT_PRINTER "%printer"
114
115 %token PERCENT_LEFT "%left"
116 %token PERCENT_RIGHT "%right"
117 %token PERCENT_NONASSOC "%nonassoc"
118 %token PERCENT_PRECEDENCE "%precedence"
119
120 %token PERCENT_PREC "%prec"
121 %token PERCENT_DPREC "%dprec"
122 %token PERCENT_MERGE "%merge"
123
124
125 /*----------------------.
126 | Global Declarations. |
127 `----------------------*/
128
129 %token
130 PERCENT_CODE "%code"
131 PERCENT_DEFAULT_PREC "%default-prec"
132 PERCENT_DEFINE "%define"
133 PERCENT_DEFINES "%defines"
134 PERCENT_EXPECT "%expect"
135 PERCENT_EXPECT_RR "%expect-rr"
136 PERCENT_FLAG "%<flag>"
137 PERCENT_FILE_PREFIX "%file-prefix"
138 PERCENT_GLR_PARSER "%glr-parser"
139 PERCENT_INITIAL_ACTION "%initial-action"
140 PERCENT_LANGUAGE "%language"
141 PERCENT_LEX_PARAM "%lex-param"
142 PERCENT_NAME_PREFIX "%name-prefix"
143 PERCENT_NO_DEFAULT_PREC "%no-default-prec"
144 PERCENT_NO_LINES "%no-lines"
145 PERCENT_NONDETERMINISTIC_PARSER
146 "%nondeterministic-parser"
147 PERCENT_OUTPUT "%output"
148 PERCENT_PARSE_PARAM "%parse-param"
149 PERCENT_REQUIRE "%require"
150 PERCENT_SKELETON "%skeleton"
151 PERCENT_START "%start"
152 PERCENT_TOKEN_TABLE "%token-table"
153 PERCENT_VERBOSE "%verbose"
154 PERCENT_YACC "%yacc"
155 ;
156
157 %token BRACED_CODE "{...}"
158 %token CHAR "char"
159 %token EPILOGUE "epilogue"
160 %token EQUAL "="
161 %token ID "identifier"
162 %token ID_COLON "identifier:"
163 %token PERCENT_PERCENT "%%"
164 %token PIPE "|"
165 %token PROLOGUE "%{...%}"
166 %token SEMICOLON ";"
167 %token TAG "<tag>"
168 %token TAG_ANY "<*>"
169 %token TAG_NONE "<>"
170
171 %type <character> CHAR
172 %printer { fputs (char_name ($$), stderr); } CHAR
173
174 /* braceless is not to be used for rule or symbol actions, as it
175 calls code_props_plain_init. */
176 %type <chars> STRING "%{...%}" EPILOGUE braceless content.opt
177 %type <code> "{...}"
178 %printer { fputs (quotearg_style (c_quoting_style, $$), stderr); }
179 STRING
180 %printer { fprintf (stderr, "{\n%s\n}", $$); }
181 braceless content.opt "{...}" "%{...%}" EPILOGUE
182
183 %type <uniqstr> TAG ID ID_COLON PERCENT_FLAG variable
184 %printer { fputs ($$, stderr); } ID variable
185 %printer { fprintf (stderr, "%s:", $$); } ID_COLON
186 %printer { fprintf (stderr, "%%%s", $$); } PERCENT_FLAG
187 %printer { fprintf (stderr, "<%s>", $$); } TAG
188
189 %type <integer> INT
190 %printer { fprintf (stderr, "%d", $$); } INT
191
192 %type <symbol> id id_colon symbol symbol.prec string_as_id
193 %printer { fprintf (stderr, "%s", $$->tag); } id symbol string_as_id
194 %printer { fprintf (stderr, "%s:", $$->tag); } id_colon
195
196 %type <assoc> precedence_declarator
197 %type <list> symbols.1 symbols.prec generic_symlist generic_symlist_item
198 %%
199
200 input:
201 prologue_declarations "%%" grammar epilogue.opt
202 ;
203
204
205 /*------------------------------------.
206 | Declarations: before the first %%. |
207 `------------------------------------*/
208
209 prologue_declarations:
210 /* Nothing */
211 | prologue_declarations prologue_declaration
212 ;
213
214 prologue_declaration:
215 grammar_declaration
216 | "%{...%}"
217 {
218 code_props plain_code;
219 code_props_plain_init (&plain_code, $1, @1);
220 code_props_translate_code (&plain_code);
221 gram_scanner_last_string_free ();
222 muscle_code_grow (union_seen ? "post_prologue" : "pre_prologue",
223 plain_code.code, @1);
224 code_scanner_last_string_free ();
225 }
226 | "%<flag>"
227 {
228 muscle_percent_define_ensure ($1, @1, true);
229 }
230 | "%define" variable content.opt
231 {
232 muscle_percent_define_insert ($2, @2, $3,
233 MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
234 }
235 | "%defines" { defines_flag = true; }
236 | "%defines" STRING
237 {
238 defines_flag = true;
239 spec_defines_file = xstrdup ($2);
240 }
241 | "%expect" INT { expected_sr_conflicts = $2; }
242 | "%expect-rr" INT { expected_rr_conflicts = $2; }
243 | "%file-prefix" STRING { spec_file_prefix = $2; }
244 | "%file-prefix" "=" STRING { spec_file_prefix = $3; } /* deprecated */
245 | "%glr-parser"
246 {
247 nondeterministic_parser = true;
248 glr_parser = true;
249 }
250 | "%initial-action" "{...}"
251 {
252 code_props action;
253 code_props_symbol_action_init (&action, $2, @2);
254 code_props_translate_code (&action);
255 gram_scanner_last_string_free ();
256 muscle_code_grow ("initial_action", action.code, @2);
257 code_scanner_last_string_free ();
258 }
259 | "%language" STRING { language_argmatch ($2, grammar_prio, @1); }
260 | "%lex-param" "{...}" { add_param ("lex_param", $2, @2); }
261 | "%name-prefix" STRING { spec_name_prefix = $2; }
262 | "%name-prefix" "=" STRING { spec_name_prefix = $3; } /* deprecated */
263 | "%no-lines" { no_lines_flag = true; }
264 | "%nondeterministic-parser" { nondeterministic_parser = true; }
265 | "%output" STRING { spec_outfile = $2; }
266 | "%output" "=" STRING { spec_outfile = $3; } /* deprecated */
267 | "%parse-param" "{...}" { add_param ("parse_param", $2, @2); }
268 | "%require" STRING { version_check (&@2, $2); }
269 | "%skeleton" STRING
270 {
271 char const *skeleton_user = $2;
272 if (strchr (skeleton_user, '/'))
273 {
274 size_t dir_length = strlen (current_file);
275 char *skeleton_build;
276 while (dir_length && current_file[dir_length - 1] != '/')
277 --dir_length;
278 while (dir_length && current_file[dir_length - 1] == '/')
279 --dir_length;
280 skeleton_build =
281 xmalloc (dir_length + 1 + strlen (skeleton_user) + 1);
282 if (dir_length > 0)
283 {
284 strncpy (skeleton_build, current_file, dir_length);
285 skeleton_build[dir_length++] = '/';
286 }
287 strcpy (skeleton_build + dir_length, skeleton_user);
288 skeleton_user = uniqstr_new (skeleton_build);
289 free (skeleton_build);
290 }
291 skeleton_arg (skeleton_user, grammar_prio, @1);
292 }
293 | "%token-table" { token_table_flag = true; }
294 | "%verbose" { report_flag |= report_states; }
295 | "%yacc" { yacc_flag = true; }
296 | /*FIXME: Err? What is this horror doing here? */ ";"
297 ;
298
299 grammar_declaration:
300 precedence_declaration
301 | symbol_declaration
302 | "%start" symbol
303 {
304 grammar_start_symbol_set ($2, @2);
305 }
306 | "%destructor" "{...}" generic_symlist
307 {
308 symbol_list *list;
309 for (list = $3; list; list = list->next)
310 symbol_list_destructor_set (list, $2, @2);
311 symbol_list_free ($3);
312 }
313 | "%printer" "{...}" generic_symlist
314 {
315 symbol_list *list;
316 for (list = $3; list; list = list->next)
317 symbol_list_printer_set (list, $2, @2);
318 symbol_list_free ($3);
319 }
320 | "%default-prec"
321 {
322 default_prec = true;
323 }
324 | "%no-default-prec"
325 {
326 default_prec = false;
327 }
328 | "%code" braceless
329 {
330 /* Do not invoke muscle_percent_code_grow here since it invokes
331 muscle_user_name_list_grow. */
332 muscle_code_grow ("percent_code()", $2, @2);
333 code_scanner_last_string_free ();
334 }
335 | "%code" ID braceless
336 {
337 muscle_percent_code_grow ($2, @2, $3, @3);
338 code_scanner_last_string_free ();
339 }
340 ;
341
342
343 /*---------.
344 | %union. |
345 `---------*/
346
347 %token PERCENT_UNION "%union";
348
349 union_name:
350 /* Nothing. */ {}
351 | ID { muscle_code_grow ("union_name", $1, @1); }
352 ;
353
354 grammar_declaration:
355 "%union" union_name braceless
356 {
357 union_seen = true;
358 muscle_code_grow ("stype", $3, @3);
359 code_scanner_last_string_free ();
360 }
361 ;
362
363
364
365
366 symbol_declaration:
367 "%nterm" { current_class = nterm_sym; } symbol_defs.1
368 {
369 current_class = unknown_sym;
370 current_type = NULL;
371 }
372 | "%token" { current_class = token_sym; } symbol_defs.1
373 {
374 current_class = unknown_sym;
375 current_type = NULL;
376 }
377 | "%type" TAG symbols.1
378 {
379 symbol_list *list;
380 tag_seen = true;
381 for (list = $3; list; list = list->next)
382 symbol_type_set (list->content.sym, $2, @2);
383 symbol_list_free ($3);
384 }
385 ;
386
387 precedence_declaration:
388 precedence_declarator tag.opt symbols.prec
389 {
390 symbol_list *list;
391 ++current_prec;
392 for (list = $3; list; list = list->next)
393 {
394 symbol_type_set (list->content.sym, current_type, @2);
395 symbol_precedence_set (list->content.sym, current_prec, $1, @1);
396 }
397 symbol_list_free ($3);
398 current_type = NULL;
399 }
400 ;
401
402 precedence_declarator:
403 "%left" { $$ = left_assoc; }
404 | "%right" { $$ = right_assoc; }
405 | "%nonassoc" { $$ = non_assoc; }
406 | "%precedence" { $$ = precedence_assoc; }
407 ;
408
409 tag.opt:
410 /* Nothing. */ { current_type = NULL; }
411 | TAG { current_type = $1; tag_seen = true; }
412 ;
413
414 /* Just like symbols.1 but accept INT for the sake of POSIX. */
415 symbols.prec:
416 symbol.prec
417 { $$ = symbol_list_sym_new ($1, @1); }
418 | symbols.prec symbol.prec
419 { $$ = symbol_list_prepend ($1, symbol_list_sym_new ($2, @2)); }
420 ;
421
422 symbol.prec:
423 symbol { $$ = $1; }
424 | symbol INT { $$ = $1; symbol_user_token_number_set ($1, $2, @2); }
425 ;
426
427 /* One or more symbols to be %typed. */
428 symbols.1:
429 symbol
430 { $$ = symbol_list_sym_new ($1, @1); }
431 | symbols.1 symbol
432 { $$ = symbol_list_prepend ($1, symbol_list_sym_new ($2, @2)); }
433 ;
434
435 generic_symlist:
436 generic_symlist_item { $$ = $1; }
437 | generic_symlist generic_symlist_item { $$ = symbol_list_prepend ($1, $2); }
438 ;
439
440 generic_symlist_item:
441 symbol { $$ = symbol_list_sym_new ($1, @1); }
442 | TAG { $$ = symbol_list_type_new ($1, @1); }
443 | "<*>" { $$ = symbol_list_default_tagged_new (@1); }
444 | "<>" { $$ = symbol_list_default_tagless_new (@1); }
445 ;
446
447 /* One token definition. */
448 symbol_def:
449 TAG
450 {
451 current_type = $1;
452 tag_seen = true;
453 }
454 | id
455 {
456 symbol_class_set ($1, current_class, @1, true);
457 symbol_type_set ($1, current_type, @1);
458 }
459 | id INT
460 {
461 symbol_class_set ($1, current_class, @1, true);
462 symbol_type_set ($1, current_type, @1);
463 symbol_user_token_number_set ($1, $2, @2);
464 }
465 | id string_as_id
466 {
467 symbol_class_set ($1, current_class, @1, true);
468 symbol_type_set ($1, current_type, @1);
469 symbol_make_alias ($1, $2, @$);
470 }
471 | id INT string_as_id
472 {
473 symbol_class_set ($1, current_class, @1, true);
474 symbol_type_set ($1, current_type, @1);
475 symbol_user_token_number_set ($1, $2, @2);
476 symbol_make_alias ($1, $3, @$);
477 }
478 ;
479
480 /* One or more symbol definitions. */
481 symbol_defs.1:
482 symbol_def
483 | symbol_defs.1 symbol_def
484 ;
485
486
487 /*------------------------------------------.
488 | The grammar section: between the two %%. |
489 `------------------------------------------*/
490
491 grammar:
492 rules_or_grammar_declaration
493 | grammar rules_or_grammar_declaration
494 ;
495
496 /* As a Bison extension, one can use the grammar declarations in the
497 body of the grammar. */
498 rules_or_grammar_declaration:
499 rules
500 | grammar_declaration ";"
501 | error ";"
502 {
503 yyerrok;
504 }
505 ;
506
507 rules:
508 id_colon { current_lhs = $1; current_lhs_location = @1; } rhses.1
509 ;
510
511 rhses.1:
512 rhs { grammar_current_rule_end (@1); }
513 | rhses.1 "|" rhs { grammar_current_rule_end (@3); }
514 | rhses.1 ";"
515 ;
516
517 rhs:
518 /* Nothing. */
519 { grammar_current_rule_begin (current_lhs, current_lhs_location); }
520 | rhs symbol
521 { grammar_current_rule_symbol_append ($2, @2); }
522 | rhs "{...}"
523 { grammar_current_rule_action_append ($2, @2); }
524 | rhs "%prec" symbol
525 { grammar_current_rule_prec_set ($3, @3); }
526 | rhs "%dprec" INT
527 { grammar_current_rule_dprec_set ($3, @3); }
528 | rhs "%merge" TAG
529 { grammar_current_rule_merge_set ($3, @3); }
530 ;
531
532
533 /*---------------------------.
534 | variable and content.opt. |
535 `---------------------------*/
536
537 /* The STRING form of variable is deprecated and is not M4-friendly.
538 For example, M4 fails for `%define "[" "value"'. */
539 variable:
540 ID
541 | STRING { $$ = uniqstr_new ($1); }
542 ;
543
544 /* Some content or empty by default. */
545 content.opt:
546 /* Nothing. */ { $$ = ""; }
547 | STRING
548 ;
549
550
551 /*------------.
552 | braceless. |
553 `------------*/
554
555 braceless:
556 "{...}"
557 {
558 code_props plain_code;
559 $1[strlen ($1) - 1] = '\n';
560 code_props_plain_init (&plain_code, $1+1, @1);
561 code_props_translate_code (&plain_code);
562 gram_scanner_last_string_free ();
563 $$ = plain_code.code;
564 }
565 ;
566
567
568 /*--------------.
569 | Identifiers. |
570 `--------------*/
571
572 /* Identifiers are returned as uniqstr values by the scanner.
573 Depending on their use, we may need to make them genuine symbols. */
574
575 id:
576 ID
577 { $$ = symbol_from_uniqstr ($1, @1); }
578 | CHAR
579 {
580 $$ = symbol_get (char_name ($1), @1);
581 symbol_class_set ($$, token_sym, @1, false);
582 symbol_user_token_number_set ($$, $1, @1);
583 }
584 ;
585
586 id_colon:
587 ID_COLON { $$ = symbol_from_uniqstr ($1, @1); }
588 ;
589
590
591 symbol:
592 id
593 | string_as_id
594 ;
595
596 /* A string used as an ID: quote it. */
597 string_as_id:
598 STRING
599 {
600 $$ = symbol_get (quotearg_style (c_quoting_style, $1), @1);
601 symbol_class_set ($$, token_sym, @1, false);
602 }
603 ;
604
605 epilogue.opt:
606 /* Nothing. */
607 | "%%" EPILOGUE
608 {
609 code_props plain_code;
610 code_props_plain_init (&plain_code, $2, @2);
611 code_props_translate_code (&plain_code);
612 gram_scanner_last_string_free ();
613 muscle_code_grow ("epilogue", plain_code.code, @2);
614 code_scanner_last_string_free ();
615 }
616 ;
617
618 %%
619
620
621 /* Return the location of the left-hand side of a rule whose
622 right-hand side is RHS[1] ... RHS[N]. Ignore empty nonterminals in
623 the right-hand side, and return an empty location equal to the end
624 boundary of RHS[0] if the right-hand side is empty. */
625
626 static YYLTYPE
627 lloc_default (YYLTYPE const *rhs, int n)
628 {
629 int i;
630 YYLTYPE loc;
631
632 /* SGI MIPSpro 7.4.1m miscompiles "loc.start = loc.end = rhs[n].end;".
633 The bug is fixed in 7.4.2m, but play it safe for now. */
634 loc.start = rhs[n].end;
635 loc.end = rhs[n].end;
636
637 /* Ignore empty nonterminals the start of the the right-hand side.
638 Do not bother to ignore them at the end of the right-hand side,
639 since empty nonterminals have the same end as their predecessors. */
640 for (i = 1; i <= n; i++)
641 if (! equal_boundaries (rhs[i].start, rhs[i].end))
642 {
643 loc.start = rhs[i].start;
644 break;
645 }
646
647 return loc;
648 }
649
650
651 /* Add a lex-param or a parse-param (depending on TYPE) with
652 declaration DECL and location LOC. */
653
654 static void
655 add_param (char const *type, char *decl, location loc)
656 {
657 static char const alphanum[26 + 26 + 1 + 10] =
658 "abcdefghijklmnopqrstuvwxyz"
659 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
660 "_"
661 "0123456789";
662 char const *name_start = NULL;
663 char *p;
664
665 /* Stop on last actual character. */
666 for (p = decl; p[1]; p++)
667 if ((p == decl
668 || ! memchr (alphanum, p[-1], sizeof alphanum))
669 && memchr (alphanum, p[0], sizeof alphanum - 10))
670 name_start = p;
671
672 /* Strip the surrounding '{' and '}', and any blanks just inside
673 the braces. */
674 while (*--p == ' ' || *p == '\t')
675 continue;
676 p[1] = '\0';
677 while (*++decl == ' ' || *decl == '\t')
678 continue;
679
680 if (! name_start)
681 complain_at (loc, _("missing identifier in parameter declaration"));
682 else
683 {
684 char *name;
685 size_t name_len;
686
687 for (name_len = 1;
688 memchr (alphanum, name_start[name_len], sizeof alphanum);
689 name_len++)
690 continue;
691
692 name = xmalloc (name_len + 1);
693 memcpy (name, name_start, name_len);
694 name[name_len] = '\0';
695 muscle_pair_list_grow (type, decl, name);
696 free (name);
697 }
698
699 gram_scanner_last_string_free ();
700 }
701
702
703 static void
704 version_check (location const *loc, char const *version)
705 {
706 if (strverscmp (version, PACKAGE_VERSION) > 0)
707 {
708 complain_at (*loc, "require bison %s, but have %s",
709 version, PACKAGE_VERSION);
710 exit (63);
711 }
712 }
713
714 static void
715 gram_error (location const *loc, char const *msg)
716 {
717 complain_at (*loc, "%s", msg);
718 }
719
720 char const *
721 token_name (int type)
722 {
723 return yytname[YYTRANSLATE (type)];
724 }
725
726 static char const *
727 char_name (char c)
728 {
729 if (c == '\'')
730 return "'\\''";
731 else
732 {
733 char buf[4];
734 buf[0] = '\''; buf[1] = c; buf[2] = '\''; buf[3] = '\0';
735 return quotearg_style (escape_quoting_style, buf);
736 }
737 }