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1 /* Bison Grammar Parser -*- C -*-
2 Copyright (C) 2002 Free Software Foundation, Inc.
3
4 This file is part of Bison, the GNU Compiler Compiler.
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 2 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, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA
20 */
21
22
23 %debug
24 %defines
25 %locations
26 %pure-parser
27 // %error-verbose
28 %defines
29 %name-prefix="gram_"
30
31 %{
32 #include "system.h"
33 #include "complain.h"
34 #include "muscle_tab.h"
35 #include "files.h"
36 #include "getargs.h"
37 #include "output.h"
38 #include "symlist.h"
39 #include "gram.h"
40 #include "reader.h"
41 #include "conflicts.h"
42
43 /* Produce verbose parse errors. */
44 #define YYERROR_VERBOSE 1
45 #define YYLLOC_DEFAULT(Current, Rhs, N) \
46 do { \
47 if (N) \
48 { \
49 Current.first_column = Rhs[1].first_column; \
50 Current.first_line = Rhs[1].first_line; \
51 Current.last_column = Rhs[N].last_column; \
52 Current.last_line = Rhs[N].last_line; \
53 } \
54 else \
55 { \
56 Current = Rhs[0]; \
57 } \
58 } while (0)
59
60 /* Pass the control structure to YYPARSE and YYLEX. */
61 #define YYPARSE_PARAM gram_control
62 #define YYLEX_PARAM gram_control
63 /* YYPARSE receives GRAM_CONTROL as a void *. Provide a
64 correctly typed access to it. */
65 #define yycontrol ((gram_control_t *) gram_control)
66
67 /* Request detailed parse error messages, and pass them to GRAM_ERROR.
68 FIXME: depends on the undocumented availability of YYLLOC.t */
69 #undef yyerror
70 #define yyerror(Msg) \
71 gram_error (&yylloc, Msg)
72
73 #define YYPRINT(File, Type, Value) \
74 yyprint (File, Type, &Value)
75 static void yyprint (FILE *file, int type, const yystype *value);
76
77 symbol_class current_class = unknown_sym;
78 char *current_type = 0;
79 symbol_t *current_lhs;
80 location_t current_lhs_location;
81 assoc_t current_assoc;
82 int current_prec = 0;
83 braced_code_t current_braced_code = action_braced_code;
84 %}
85
86
87 /* Only NUMBERS have a value. */
88 %union
89 {
90 symbol_t *symbol;
91 symbol_list_t *list;
92 int integer;
93 char *string;
94 assoc_t assoc;
95 };
96
97 /* Define the tokens together with their human representation. */
98 %token GRAM_EOF 0 "end of file"
99 %token STRING "string"
100 %token CHARACTER "character"
101 %token INT "integer"
102
103 %token PERCENT_TOKEN "%token"
104 %token PERCENT_NTERM "%nterm"
105
106 %token PERCENT_TYPE "%type"
107 %token PERCENT_DESTRUCTOR "%destructor"
108 %token PERCENT_PRINTER "%printer"
109
110 %token PERCENT_UNION "%union"
111
112 %token PERCENT_LEFT "%left"
113 %token PERCENT_RIGHT "%right"
114 %token PERCENT_NONASSOC "%nonassoc"
115
116 %token PERCENT_PREC "%prec"
117 %token PERCENT_DPREC "%dprec"
118 %token PERCENT_MERGE "%merge"
119
120
121 /*----------------------.
122 | Global Declarations. |
123 `----------------------*/
124
125 %token
126 PERCENT_DEBUG "%debug"
127 PERCENT_DEFINE "%define"
128 PERCENT_DEFINES "%defines"
129 PERCENT_ERROR_VERBOSE "%error-verbose"
130 PERCENT_EXPECT "%expect"
131 PERCENT_FILE_PREFIX "%file-prefix"
132 PERCENT_GLR_PARSER "%glr-parser"
133 PERCENT_LEX_PARAM "%lex-param"
134 PERCENT_LOCATIONS "%locations"
135 PERCENT_NAME_PREFIX "%name-prefix"
136 PERCENT_NO_LINES "%no-lines"
137 PERCENT_OUTPUT "%output"
138 PERCENT_PARSE_PARAM "%parse-param"
139 PERCENT_PURE_PARSER "%pure-parser"
140 PERCENT_SKELETON "%skeleton"
141 PERCENT_START "%start"
142 PERCENT_TOKEN_TABLE "%token-table"
143 PERCENT_VERBOSE "%verbose"
144 PERCENT_YACC "%yacc"
145 ;
146
147 %token TYPE "type"
148 %token EQUAL "="
149 %token SEMICOLON ";"
150 %token COLON ":"
151 %token COMMA ","
152 %token PIPE "|"
153 %token ID "identifier"
154 %token PERCENT_PERCENT "%%"
155 %token PROLOGUE "%{...%}"
156 %token EPILOGUE "epilogue"
157 %token BRACED_CODE "{...}"
158
159
160 %type <string> CHARACTER TYPE STRING string_content
161 BRACED_CODE PROLOGUE EPILOGUE epilogue.opt action
162 %type <integer> INT
163 %type <symbol> ID symbol string_as_id
164 %type <assoc> precedence_declarator
165 %type <list> symbols.1
166 %%
167
168 input:
169 declarations "%%" grammar epilogue.opt
170 {
171 yycontrol->errcode = 0;
172 epilogue_set ($4, @4);
173 }
174 ;
175
176
177 /*------------------------------------.
178 | Declarations: before the first %%. |
179 `------------------------------------*/
180
181 declarations:
182 /* Nothing */
183 | declarations declaration semi_colon.opt
184 ;
185
186 declaration:
187 grammar_declaration
188 | PROLOGUE { prologue_augment ($1, @1); }
189 | "%debug" { debug_flag = 1; }
190 | "%define" string_content string_content { muscle_insert ($2, $3); }
191 | "%defines" { defines_flag = 1; }
192 | "%error-verbose" { error_verbose = 1; }
193 | "%expect" INT { expected_conflicts = $2; }
194 | "%file-prefix" "=" string_content { spec_file_prefix = $3; }
195 | "%glr-parser" { glr_parser = 1; }
196 | "%lex-param" string_content "," string_content
197 { muscle_pair_list_grow ("lex_param", $2, $4); }
198 | "%locations" { locations_flag = 1; }
199 | "%name-prefix" "=" string_content { spec_name_prefix = $3; }
200 | "%no-lines" { no_lines_flag = 1; }
201 | "%output" "=" string_content { spec_outfile = $3; }
202 | "%parse-param" string_content "," string_content
203 { muscle_pair_list_grow ("parse_param", $2, $4); }
204 | "%pure-parser" { pure_parser = 1; }
205 | "%skeleton" string_content { skeleton = $2; }
206 | "%token-table" { token_table_flag = 1; }
207 | "%verbose" { report_flag = 1; }
208 | "%yacc" { yacc_flag = 1; }
209 ;
210
211 grammar_declaration:
212 precedence_declaration
213 | symbol_declaration
214 | "%start" symbol
215 {
216 grammar_start_symbol_set ($2, @2);
217 }
218 | "%union" BRACED_CODE
219 {
220 typed = 1;
221 MUSCLE_INSERT_INT ("stype_line", @2.first_line);
222 muscle_insert ("stype", $2);
223 }
224 | "%destructor"
225 { current_braced_code = destructor_braced_code; }
226 BRACED_CODE symbols.1
227 {
228 symbol_list_t *list;
229 for (list = $4; list; list = list->next)
230 symbol_destructor_set (list->sym, $3, @3);
231 symbol_list_free ($4);
232 current_braced_code = action_braced_code;
233 }
234 | "%printer"
235 { current_braced_code = printer_braced_code; }
236 BRACED_CODE symbols.1
237 {
238 symbol_list_t *list;
239 for (list = $4; list; list = list->next)
240 symbol_printer_set (list->sym, $3, list->location);
241 symbol_list_free ($4);
242 current_braced_code = action_braced_code;
243 }
244 ;
245
246 symbol_declaration:
247 "%nterm" { current_class = nterm_sym; } symbol_defs.1
248 {
249 current_class = unknown_sym;
250 current_type = NULL;
251 }
252 | "%token" { current_class = token_sym; } symbol_defs.1
253 {
254 current_class = unknown_sym;
255 current_type = NULL;
256 }
257 | "%type" TYPE symbols.1
258 {
259 symbol_list_t *list;
260 for (list = $3; list; list = list->next)
261 symbol_type_set (list->sym, $2, @2);
262 symbol_list_free ($3);
263 }
264 ;
265
266 precedence_declaration:
267 precedence_declarator type.opt symbols.1
268 {
269 symbol_list_t *list;
270 ++current_prec;
271 for (list = $3; list; list = list->next)
272 {
273 symbol_type_set (list->sym, current_type, @2);
274 symbol_precedence_set (list->sym, current_prec, $1, @1);
275 }
276 symbol_list_free ($3);
277 current_type = NULL;
278 }
279 ;
280
281 precedence_declarator:
282 "%left" { $$ = left_assoc; }
283 | "%right" { $$ = right_assoc; }
284 | "%nonassoc" { $$ = non_assoc; }
285 ;
286
287 type.opt:
288 /* Nothing. */ { current_type = NULL;}
289 | TYPE { current_type = $1; }
290 ;
291
292 /* One or more nonterminals to be %typed. */
293
294 symbols.1:
295 symbol { $$ = symbol_list_new ($1, @1); }
296 | symbols.1 symbol { $$ = symbol_list_prepend ($1, $2, @2); }
297 ;
298
299 /* One token definition. */
300 symbol_def:
301 TYPE
302 {
303 current_type = $1;
304 }
305 | ID
306 {
307 symbol_class_set ($1, current_class, @1);
308 symbol_type_set ($1, current_type, @1);
309 }
310 | ID INT
311 {
312 symbol_class_set ($1, current_class, @1);
313 symbol_type_set ($1, current_type, @1);
314 symbol_user_token_number_set ($1, $2, @2);
315 }
316 | ID string_as_id
317 {
318 symbol_class_set ($1, current_class, @1);
319 symbol_type_set ($1, current_type, @1);
320 symbol_make_alias ($1, $2, @$);
321 }
322 | ID INT string_as_id
323 {
324 symbol_class_set ($1, current_class, @1);
325 symbol_type_set ($1, current_type, @1);
326 symbol_user_token_number_set ($1, $2, @2);
327 symbol_make_alias ($1, $3, @$);
328 }
329 ;
330
331 /* One or more symbol definitions. */
332 symbol_defs.1:
333 symbol_def
334 {;}
335 | symbol_defs.1 symbol_def
336 {;}
337 ;
338
339
340 /*------------------------------------------.
341 | The grammar section: between the two %%. |
342 `------------------------------------------*/
343
344 grammar:
345 rules_or_grammar_declaration
346 | grammar rules_or_grammar_declaration
347 ;
348
349 /* As a Bison extension, one can use the grammar declarations in the
350 body of the grammar. But to remain LALR(1), they must be ended
351 with a semi-colon. */
352 rules_or_grammar_declaration:
353 rules
354 | grammar_declaration ";"
355 {
356 if (yacc_flag)
357 complain_at (@$, _("POSIX forbids declarations in the grammar"));
358 }
359 | error ";"
360 {
361 yyerrok;
362 }
363 ;
364
365 rules:
366 ID ":" { current_lhs = $1; current_lhs_location = @1; } rhses.1 ";"
367 {;}
368 ;
369
370 rhses.1:
371 rhs { grammar_rule_end (@1); }
372 | rhses.1 "|" rhs { grammar_rule_end (@3); }
373 ;
374
375 rhs:
376 /* Nothing. */
377 { grammar_rule_begin (current_lhs, current_lhs_location); }
378 | rhs symbol
379 { grammar_current_rule_symbol_append ($2, @2); }
380 | rhs action
381 { grammar_current_rule_action_append ($2, @2); }
382 | rhs "%prec" symbol
383 { grammar_current_rule_prec_set ($3, @3); }
384 | rhs "%dprec" INT
385 { grammar_current_rule_dprec_set ($3, @3); }
386 | rhs "%merge" TYPE
387 { grammar_current_rule_merge_set ($3, @3); }
388 ;
389
390 symbol:
391 ID { $$ = $1; }
392 | string_as_id { $$ = $1; }
393 | CHARACTER { $$ = symbol_get ($1, @1); }
394 ;
395
396 action:
397 BRACED_CODE
398 { $$ = $1; }
399 ;
400
401 /* A string used as an ID: we have to keep the quotes. */
402 string_as_id:
403 STRING
404 {
405 $$ = symbol_get ($1, @1);
406 symbol_class_set ($$, token_sym, @1);
407 }
408 ;
409
410 /* A string used for its contents. Strip the quotes. */
411 string_content:
412 STRING
413 {
414 $$ = $1 + 1;
415 $$[strlen ($$) - 1] = '\0';
416 };
417
418
419 epilogue.opt:
420 /* Nothing. */
421 {
422 $$ = xstrdup ("");
423 }
424 | "%%" EPILOGUE
425 {
426 $$ = $2;
427 }
428 ;
429
430 semi_colon.opt:
431 /* Nothing. */
432 | ";"
433 ;
434 %%
435 /*------------------------------------------------------------------.
436 | When debugging the parser, display tokens' locations and values. |
437 `------------------------------------------------------------------*/
438
439 static void
440 yyprint (FILE *file,
441 int type, const yystype *value)
442 {
443 fputc (' ', file);
444 switch (type)
445 {
446 case CHARACTER:
447 fprintf (file, " = '%s'", value->string);
448 break;
449
450 case ID:
451 fprintf (file, " = %s", value->symbol->tag);
452 break;
453
454 case INT:
455 fprintf (file, " = %d", value->integer);
456 break;
457
458 case STRING:
459 fprintf (file, " = \"%s\"", value->string);
460 break;
461
462 case TYPE:
463 fprintf (file, " = <%s>", value->string);
464 break;
465
466 case BRACED_CODE:
467 case PROLOGUE:
468 case EPILOGUE:
469 fprintf (file, " = {{ %s }}", value->string);
470 break;
471 }
472 }
473
474 void
475 gram_error (location_t *yylloc, const char *msg)
476 {
477 complain_at (*yylloc, "%s", msg);
478 }