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| 1 /* Input parser for Bison |
| 2 |
| 3 Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003, |
| 4 2005, 2006, 2007 Free Software 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 <quotearg.h> |
| 25 |
| 26 #include "complain.h" |
| 27 #include "conflicts.h" |
| 28 #include "files.h" |
| 29 #include "getargs.h" |
| 30 #include "gram.h" |
| 31 #include "muscle_tab.h" |
| 32 #include "reader.h" |
| 33 #include "symlist.h" |
| 34 #include "symtab.h" |
| 35 #include "scan-gram.h" |
| 36 #include "scan-code.h" |
| 37 |
| 38 static void check_and_convert_grammar (void); |
| 39 |
| 40 static symbol_list *grammar = NULL; |
| 41 static bool start_flag = false; |
| 42 merger_list *merge_functions; |
| 43 |
| 44 /* Was %union seen? */ |
| 45 bool union_seen = false; |
| 46 |
| 47 /* Was a tag seen? */ |
| 48 bool tag_seen = false; |
| 49 |
| 50 /* Should rules have a default precedence? */ |
| 51 bool default_prec = true; |
| 52 |
| 53 /*-----------------------. |
| 54 | Set the start symbol. | |
| 55 `-----------------------*/ |
| 56 |
| 57 void |
| 58 grammar_start_symbol_set (symbol *sym, location loc) |
| 59 { |
| 60 if (start_flag) |
| 61 complain_at (loc, _("multiple %s declarations"), "%start"); |
| 62 else |
| 63 { |
| 64 start_flag = true; |
| 65 startsymbol = sym; |
| 66 startsymbol_location = loc; |
| 67 } |
| 68 } |
| 69 |
| 70 |
| 71 |
| 72 /*------------------------------------------------------------------------. |
| 73 | Return the merger index for a merging function named NAME. Records the | |
| 74 | function, if new, in MERGER_LIST. | |
| 75 `------------------------------------------------------------------------*/ |
| 76 |
| 77 static int |
| 78 get_merge_function (uniqstr name) |
| 79 { |
| 80 merger_list *syms; |
| 81 merger_list head; |
| 82 int n; |
| 83 |
| 84 if (! glr_parser) |
| 85 return 0; |
| 86 |
| 87 head.next = merge_functions; |
| 88 for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1) |
| 89 if (UNIQSTR_EQ (name, syms->next->name)) |
| 90 break; |
| 91 if (syms->next == NULL) |
| 92 { |
| 93 syms->next = xmalloc (sizeof syms->next[0]); |
| 94 syms->next->name = uniqstr_new (name); |
| 95 /* After all symbol type declarations have been parsed, packgram invokes |
| 96 record_merge_function_type to set the type. */ |
| 97 syms->next->type = NULL; |
| 98 syms->next->next = NULL; |
| 99 merge_functions = head.next; |
| 100 } |
| 101 return n; |
| 102 } |
| 103 |
| 104 /*-------------------------------------------------------------------------. |
| 105 | For the existing merging function with index MERGER, record the result | |
| 106 | type as TYPE as required by the lhs of the rule whose %merge declaration | |
| 107 | is at DECLARATION_LOC. | |
| 108 `-------------------------------------------------------------------------*/ |
| 109 |
| 110 static void |
| 111 record_merge_function_type (int merger, uniqstr type, location declaration_loc) |
| 112 { |
| 113 int merger_find; |
| 114 merger_list *merge_function; |
| 115 |
| 116 if (merger <= 0) |
| 117 return; |
| 118 |
| 119 if (type == NULL) |
| 120 type = uniqstr_new (""); |
| 121 |
| 122 merger_find = 1; |
| 123 for (merge_function = merge_functions; |
| 124 merge_function != NULL && merger_find != merger; |
| 125 merge_function = merge_function->next) |
| 126 merger_find += 1; |
| 127 aver (merge_function != NULL && merger_find == merger); |
| 128 if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type)) |
| 129 { |
| 130 complain_at (declaration_loc, |
| 131 _("result type clash on merge function `%s': <%s> != <%s>"), |
| 132 merge_function->name, type, merge_function->type); |
| 133 complain_at (merge_function->type_declaration_location, |
| 134 _("previous declaration")); |
| 135 } |
| 136 merge_function->type = uniqstr_new (type); |
| 137 merge_function->type_declaration_location = declaration_loc; |
| 138 } |
| 139 |
| 140 /*--------------------------------------. |
| 141 | Free all merge-function definitions. | |
| 142 `--------------------------------------*/ |
| 143 |
| 144 void |
| 145 free_merger_functions (void) |
| 146 { |
| 147 merger_list *L0 = merge_functions; |
| 148 while (L0) |
| 149 { |
| 150 merger_list *L1 = L0->next; |
| 151 free (L0); |
| 152 L0 = L1; |
| 153 } |
| 154 } |
| 155 |
| 156 |
| 157 /*-------------------------------------------------------------------. |
| 158 | Parse the input grammar into a one symbol_list structure. Each | |
| 159 | rule is represented by a sequence of symbols: the left hand side | |
| 160 | followed by the contents of the right hand side, followed by a | |
| 161 | null pointer instead of a symbol to terminate the rule. The next | |
| 162 | symbol is the lhs of the following rule. | |
| 163 | | |
| 164 | All actions are copied out, labelled by the rule number they apply | |
| 165 | to. | |
| 166 `-------------------------------------------------------------------*/ |
| 167 |
| 168 /* The (currently) last symbol of GRAMMAR. */ |
| 169 static symbol_list *grammar_end = NULL; |
| 170 |
| 171 /* Append SYM to the grammar. */ |
| 172 static void |
| 173 grammar_symbol_append (symbol *sym, location loc) |
| 174 { |
| 175 symbol_list *p = symbol_list_sym_new (sym, loc); |
| 176 |
| 177 if (grammar_end) |
| 178 grammar_end->next = p; |
| 179 else |
| 180 grammar = p; |
| 181 |
| 182 grammar_end = p; |
| 183 |
| 184 /* A null SYM stands for an end of rule; it is not an actual |
| 185 part of it. */ |
| 186 if (sym) |
| 187 ++nritems; |
| 188 } |
| 189 |
| 190 /* The rule currently being defined, and the previous rule. |
| 191 CURRENT_RULE points to the first LHS of the current rule, while |
| 192 PREVIOUS_RULE_END points to the *end* of the previous rule (NULL). */ |
| 193 static symbol_list *current_rule = NULL; |
| 194 static symbol_list *previous_rule_end = NULL; |
| 195 |
| 196 |
| 197 /*----------------------------------------------. |
| 198 | Create a new rule for LHS in to the GRAMMAR. | |
| 199 `----------------------------------------------*/ |
| 200 |
| 201 void |
| 202 grammar_current_rule_begin (symbol *lhs, location loc) |
| 203 { |
| 204 /* Start a new rule and record its lhs. */ |
| 205 ++nrules; |
| 206 previous_rule_end = grammar_end; |
| 207 grammar_symbol_append (lhs, loc); |
| 208 current_rule = grammar_end; |
| 209 |
| 210 /* Mark the rule's lhs as a nonterminal if not already so. */ |
| 211 if (lhs->class == unknown_sym) |
| 212 { |
| 213 lhs->class = nterm_sym; |
| 214 lhs->number = nvars; |
| 215 ++nvars; |
| 216 } |
| 217 else if (lhs->class == token_sym) |
| 218 complain_at (loc, _("rule given for %s, which is a token"), lhs->tag); |
| 219 } |
| 220 |
| 221 |
| 222 /*----------------------------------------------------------------------. |
| 223 | A symbol should be used if either: | |
| 224 | 1. It has a destructor. | |
| 225 | 2. --warnings=midrule-values and the symbol is a mid-rule symbol | |
| 226 | (i.e., the generated LHS replacing a mid-rule action) that was | |
| 227 | assigned to or used, as in "exp: { $$ = 1; } { $$ = $1; }". | |
| 228 `----------------------------------------------------------------------*/ |
| 229 |
| 230 static bool |
| 231 symbol_should_be_used (symbol_list const *s) |
| 232 { |
| 233 if (symbol_destructor_get (s->content.sym)->code) |
| 234 return true; |
| 235 if (warnings_flag & warnings_midrule_values) |
| 236 return ((s->midrule && s->midrule->action_props.is_value_used) |
| 237 || (s->midrule_parent_rule |
| 238 && symbol_list_n_get (s->midrule_parent_rule, |
| 239 s->midrule_parent_rhs_index) |
| 240 ->action_props.is_value_used)); |
| 241 return false; |
| 242 } |
| 243 |
| 244 /*----------------------------------------------------------------. |
| 245 | Check that the rule R is properly defined. For instance, there | |
| 246 | should be no type clash on the default action. | |
| 247 `----------------------------------------------------------------*/ |
| 248 |
| 249 static void |
| 250 grammar_rule_check (const symbol_list *r) |
| 251 { |
| 252 /* Type check. |
| 253 |
| 254 If there is an action, then there is nothing we can do: the user |
| 255 is allowed to shoot herself in the foot. |
| 256 |
| 257 Don't worry about the default action if $$ is untyped, since $$'s |
| 258 value can't be used. */ |
| 259 if (!r->action_props.code && r->content.sym->type_name) |
| 260 { |
| 261 symbol *first_rhs = r->next->content.sym; |
| 262 /* If $$ is being set in default way, report if any type mismatch. */ |
| 263 if (first_rhs) |
| 264 { |
| 265 char const *lhs_type = r->content.sym->type_name; |
| 266 const char *rhs_type = |
| 267 first_rhs->type_name ? first_rhs->type_name : ""; |
| 268 if (!UNIQSTR_EQ (lhs_type, rhs_type)) |
| 269 warn_at (r->location, |
| 270 _("type clash on default action: <%s> != <%s>"), |
| 271 lhs_type, rhs_type); |
| 272 } |
| 273 /* Warn if there is no default for $$ but we need one. */ |
| 274 else |
| 275 warn_at (r->location, |
| 276 _("empty rule for typed nonterminal, and no action")); |
| 277 } |
| 278 |
| 279 /* Check that symbol values that should be used are in fact used. */ |
| 280 { |
| 281 symbol_list const *l = r; |
| 282 int n = 0; |
| 283 for (; l && l->content.sym; l = l->next, ++n) |
| 284 if (! (l->action_props.is_value_used |
| 285 || !symbol_should_be_used (l) |
| 286 /* The default action, $$ = $1, `uses' both. */ |
| 287 || (!r->action_props.code && (n == 0 || n == 1)))) |
| 288 { |
| 289 if (n) |
| 290 warn_at (r->location, _("unused value: $%d"), n); |
| 291 else |
| 292 warn_at (r->location, _("unset value: $$")); |
| 293 } |
| 294 } |
| 295 } |
| 296 |
| 297 |
| 298 /*-------------------------------------. |
| 299 | End the currently being grown rule. | |
| 300 `-------------------------------------*/ |
| 301 |
| 302 void |
| 303 grammar_current_rule_end (location loc) |
| 304 { |
| 305 /* Put an empty link in the list to mark the end of this rule */ |
| 306 grammar_symbol_append (NULL, grammar_end->location); |
| 307 current_rule->location = loc; |
| 308 } |
| 309 |
| 310 |
| 311 /*-------------------------------------------------------------------. |
| 312 | The previous action turns out the be a mid-rule action. Attach it | |
| 313 | to the current rule, i.e., create a dummy symbol, attach it this | |
| 314 | mid-rule action, and append this dummy nonterminal to the current | |
| 315 | rule. | |
| 316 `-------------------------------------------------------------------*/ |
| 317 |
| 318 void |
| 319 grammar_midrule_action (void) |
| 320 { |
| 321 /* Since the action was written out with this rule's number, we must |
| 322 give the new rule this number by inserting the new rule before |
| 323 it. */ |
| 324 |
| 325 /* Make a DUMMY nonterminal, whose location is that of the midrule |
| 326 action. Create the MIDRULE. */ |
| 327 location dummy_location = current_rule->action_props.location; |
| 328 symbol *dummy = dummy_symbol_get (dummy_location); |
| 329 symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location); |
| 330 |
| 331 /* Make a new rule, whose body is empty, before the current one, so |
| 332 that the action just read can belong to it. */ |
| 333 ++nrules; |
| 334 ++nritems; |
| 335 /* Attach its location and actions to that of the DUMMY. */ |
| 336 midrule->location = dummy_location; |
| 337 code_props_rule_action_init (&midrule->action_props, |
| 338 current_rule->action_props.code, |
| 339 current_rule->action_props.location, |
| 340 midrule); |
| 341 code_props_none_init (¤t_rule->action_props); |
| 342 |
| 343 if (previous_rule_end) |
| 344 previous_rule_end->next = midrule; |
| 345 else |
| 346 grammar = midrule; |
| 347 |
| 348 /* End the dummy's rule. */ |
| 349 midrule->next = symbol_list_sym_new (NULL, dummy_location); |
| 350 midrule->next->next = current_rule; |
| 351 |
| 352 previous_rule_end = midrule->next; |
| 353 |
| 354 /* Insert the dummy nonterminal replacing the midrule action into |
| 355 the current rule. Bind it to its dedicated rule. */ |
| 356 grammar_current_rule_symbol_append (dummy, dummy_location); |
| 357 grammar_end->midrule = midrule; |
| 358 midrule->midrule_parent_rule = current_rule; |
| 359 midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next); |
| 360 } |
| 361 |
| 362 /* Set the precedence symbol of the current rule to PRECSYM. */ |
| 363 |
| 364 void |
| 365 grammar_current_rule_prec_set (symbol *precsym, location loc) |
| 366 { |
| 367 symbol_class_set (precsym, token_sym, loc, false); |
| 368 if (current_rule->ruleprec) |
| 369 complain_at (loc, _("only one %s allowed per rule"), "%prec"); |
| 370 current_rule->ruleprec = precsym; |
| 371 } |
| 372 |
| 373 /* Attach dynamic precedence DPREC to the current rule. */ |
| 374 |
| 375 void |
| 376 grammar_current_rule_dprec_set (int dprec, location loc) |
| 377 { |
| 378 if (! glr_parser) |
| 379 warn_at (loc, _("%s affects only GLR parsers"), "%dprec"); |
| 380 if (dprec <= 0) |
| 381 complain_at (loc, _("%s must be followed by positive number"), "%dprec"); |
| 382 else if (current_rule->dprec != 0) |
| 383 complain_at (loc, _("only one %s allowed per rule"), "%dprec"); |
| 384 current_rule->dprec = dprec; |
| 385 } |
| 386 |
| 387 /* Attach a merge function NAME with argument type TYPE to current |
| 388 rule. */ |
| 389 |
| 390 void |
| 391 grammar_current_rule_merge_set (uniqstr name, location loc) |
| 392 { |
| 393 if (! glr_parser) |
| 394 warn_at (loc, _("%s affects only GLR parsers"), "%merge"); |
| 395 if (current_rule->merger != 0) |
| 396 complain_at (loc, _("only one %s allowed per rule"), "%merge"); |
| 397 current_rule->merger = get_merge_function (name); |
| 398 current_rule->merger_declaration_location = loc; |
| 399 } |
| 400 |
| 401 /* Attach SYM to the current rule. If needed, move the previous |
| 402 action as a mid-rule action. */ |
| 403 |
| 404 void |
| 405 grammar_current_rule_symbol_append (symbol *sym, location loc) |
| 406 { |
| 407 if (current_rule->action_props.code) |
| 408 grammar_midrule_action (); |
| 409 grammar_symbol_append (sym, loc); |
| 410 } |
| 411 |
| 412 /* Attach an ACTION to the current rule. */ |
| 413 |
| 414 void |
| 415 grammar_current_rule_action_append (const char *action, location loc) |
| 416 { |
| 417 if (current_rule->action_props.code) |
| 418 grammar_midrule_action (); |
| 419 /* After all symbol declarations have been parsed, packgram invokes |
| 420 code_props_translate_code. */ |
| 421 code_props_rule_action_init (¤t_rule->action_props, action, loc, |
| 422 current_rule); |
| 423 } |
| 424 |
| 425 |
| 426 /*---------------------------------------------------------------. |
| 427 | Convert the rules into the representation using RRHS, RLHS and | |
| 428 | RITEM. | |
| 429 `---------------------------------------------------------------*/ |
| 430 |
| 431 static void |
| 432 packgram (void) |
| 433 { |
| 434 unsigned int itemno = 0; |
| 435 rule_number ruleno = 0; |
| 436 symbol_list *p = grammar; |
| 437 |
| 438 ritem = xnmalloc (nritems + 1, sizeof *ritem); |
| 439 |
| 440 /* This sentinel is used by build_relations in gram.c. */ |
| 441 *ritem++ = 0; |
| 442 |
| 443 rules = xnmalloc (nrules, sizeof *rules); |
| 444 |
| 445 while (p) |
| 446 { |
| 447 int rule_length = 0; |
| 448 symbol *ruleprec = p->ruleprec; |
| 449 record_merge_function_type (p->merger, p->content.sym->type_name, |
| 450 p->merger_declaration_location); |
| 451 rules[ruleno].user_number = ruleno; |
| 452 rules[ruleno].number = ruleno; |
| 453 rules[ruleno].lhs = p->content.sym; |
| 454 rules[ruleno].rhs = ritem + itemno; |
| 455 rules[ruleno].prec = NULL; |
| 456 rules[ruleno].dprec = p->dprec; |
| 457 rules[ruleno].merger = p->merger; |
| 458 rules[ruleno].precsym = NULL; |
| 459 rules[ruleno].location = p->location; |
| 460 rules[ruleno].useful = true; |
| 461 rules[ruleno].action = p->action_props.code; |
| 462 rules[ruleno].action_location = p->action_props.location; |
| 463 |
| 464 /* If the midrule's $$ is set or its $n is used, remove the `$' from the |
| 465 symbol name so that it's a user-defined symbol so that the default |
| 466 %destructor and %printer apply. */ |
| 467 if (p->midrule_parent_rule |
| 468 && (p->action_props.is_value_used |
| 469 || symbol_list_n_get (p->midrule_parent_rule, |
| 470 p->midrule_parent_rhs_index) |
| 471 ->action_props.is_value_used)) |
| 472 p->content.sym->tag += 1; |
| 473 |
| 474 /* Don't check the generated rule 0. It has no action, so some rhs |
| 475 symbols may appear unused, but the parsing algorithm ensures that |
| 476 %destructor's are invoked appropriately. */ |
| 477 if (p != grammar) |
| 478 grammar_rule_check (p); |
| 479 |
| 480 for (p = p->next; p && p->content.sym; p = p->next) |
| 481 { |
| 482 ++rule_length; |
| 483 |
| 484 /* Don't allow rule_length == INT_MAX, since that might |
| 485 cause confusion with strtol if INT_MAX == LONG_MAX. */ |
| 486 if (rule_length == INT_MAX) |
| 487 fatal_at (rules[ruleno].location, _("rule is too long")); |
| 488 |
| 489 /* item_number = symbol_number. |
| 490 But the former needs to contain more: negative rule numbers. */ |
| 491 ritem[itemno++] = |
| 492 symbol_number_as_item_number (p->content.sym->number); |
| 493 /* A rule gets by default the precedence and associativity |
| 494 of its last token. */ |
| 495 if (p->content.sym->class == token_sym && default_prec) |
| 496 rules[ruleno].prec = p->content.sym; |
| 497 } |
| 498 |
| 499 /* If this rule has a %prec, |
| 500 the specified symbol's precedence replaces the default. */ |
| 501 if (ruleprec) |
| 502 { |
| 503 rules[ruleno].precsym = ruleprec; |
| 504 rules[ruleno].prec = ruleprec; |
| 505 } |
| 506 /* An item ends by the rule number (negated). */ |
| 507 ritem[itemno++] = rule_number_as_item_number (ruleno); |
| 508 aver (itemno < ITEM_NUMBER_MAX); |
| 509 ++ruleno; |
| 510 aver (ruleno < RULE_NUMBER_MAX); |
| 511 |
| 512 if (p) |
| 513 p = p->next; |
| 514 } |
| 515 |
| 516 aver (itemno == nritems); |
| 517 |
| 518 if (trace_flag & trace_sets) |
| 519 ritem_print (stderr); |
| 520 } |
| 521 |
| 522 /*------------------------------------------------------------------. |
| 523 | Read in the grammar specification and record it in the format | |
| 524 | described in gram.h. All actions are copied into ACTION_OBSTACK, | |
| 525 | in each case forming the body of a C function (YYACTION) which | |
| 526 | contains a switch statement to decide which action to execute. | |
| 527 `------------------------------------------------------------------*/ |
| 528 |
| 529 void |
| 530 reader (void) |
| 531 { |
| 532 /* Initialize the symbol table. */ |
| 533 symbols_new (); |
| 534 |
| 535 /* Construct the accept symbol. */ |
| 536 accept = symbol_get ("$accept", empty_location); |
| 537 accept->class = nterm_sym; |
| 538 accept->number = nvars++; |
| 539 |
| 540 /* Construct the error token */ |
| 541 errtoken = symbol_get ("error", empty_location); |
| 542 errtoken->class = token_sym; |
| 543 errtoken->number = ntokens++; |
| 544 |
| 545 /* Construct a token that represents all undefined literal tokens. |
| 546 It is always token number 2. */ |
| 547 undeftoken = symbol_get ("$undefined", empty_location); |
| 548 undeftoken->class = token_sym; |
| 549 undeftoken->number = ntokens++; |
| 550 |
| 551 gram_in = xfopen (grammar_file, "r"); |
| 552 |
| 553 gram__flex_debug = trace_flag & trace_scan; |
| 554 gram_debug = trace_flag & trace_parse; |
| 555 gram_scanner_initialize (); |
| 556 gram_parse (); |
| 557 |
| 558 if (! complaint_issued) |
| 559 check_and_convert_grammar (); |
| 560 |
| 561 xfclose (gram_in); |
| 562 } |
| 563 |
| 564 |
| 565 /*-------------------------------------------------------------. |
| 566 | Check the grammar that has just been read, and convert it to | |
| 567 | internal form. | |
| 568 `-------------------------------------------------------------*/ |
| 569 |
| 570 static void |
| 571 check_and_convert_grammar (void) |
| 572 { |
| 573 /* Grammar has been read. Do some checking. */ |
| 574 if (nrules == 0) |
| 575 fatal (_("no rules in the input grammar")); |
| 576 |
| 577 /* Report any undefined symbols and consider them nonterminals. */ |
| 578 symbols_check_defined (); |
| 579 |
| 580 /* If the user did not define her ENDTOKEN, do it now. */ |
| 581 if (!endtoken) |
| 582 { |
| 583 endtoken = symbol_get ("$end", empty_location); |
| 584 endtoken->class = token_sym; |
| 585 endtoken->number = 0; |
| 586 /* Value specified by POSIX. */ |
| 587 endtoken->user_token_number = 0; |
| 588 } |
| 589 |
| 590 /* Find the start symbol if no %start. */ |
| 591 if (!start_flag) |
| 592 { |
| 593 symbol_list *node; |
| 594 for (node = grammar; |
| 595 node != NULL && symbol_is_dummy (node->content.sym); |
| 596 node = node->next) |
| 597 { |
| 598 for (node = node->next; |
| 599 node != NULL && node->content.sym != NULL; |
| 600 node = node->next) |
| 601 ; |
| 602 } |
| 603 aver (node != NULL); |
| 604 grammar_start_symbol_set (node->content.sym, |
| 605 node->content.sym->location); |
| 606 } |
| 607 |
| 608 /* Insert the initial rule, whose line is that of the first rule |
| 609 (not that of the start symbol): |
| 610 |
| 611 accept: %start EOF. */ |
| 612 { |
| 613 symbol_list *p = symbol_list_sym_new (accept, empty_location); |
| 614 p->location = grammar->location; |
| 615 p->next = symbol_list_sym_new (startsymbol, empty_location); |
| 616 p->next->next = symbol_list_sym_new (endtoken, empty_location); |
| 617 p->next->next->next = symbol_list_sym_new (NULL, empty_location); |
| 618 p->next->next->next->next = grammar; |
| 619 nrules += 1; |
| 620 nritems += 3; |
| 621 grammar = p; |
| 622 } |
| 623 |
| 624 aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars); |
| 625 |
| 626 /* Assign the symbols their symbol numbers. Write #defines for the |
| 627 token symbols into FDEFINES if requested. */ |
| 628 symbols_pack (); |
| 629 |
| 630 /* Scan rule actions after invoking symbol_check_alias_consistency (in |
| 631 symbols_pack above) so that token types are set correctly before the rule |
| 632 action type checking. |
| 633 |
| 634 Before invoking grammar_rule_check (in packgram below) on any rule, make |
| 635 sure all actions have already been scanned in order to set `used' flags. |
| 636 Otherwise, checking that a midrule's $$ should be set will not always work |
| 637 properly because the check must forward-reference the midrule's parent |
| 638 rule. For the same reason, all the `used' flags must be set before |
| 639 checking whether to remove `$' from any midrule symbol name (also in |
| 640 packgram). */ |
| 641 { |
| 642 symbol_list *sym; |
| 643 for (sym = grammar; sym; sym = sym->next) |
| 644 code_props_translate_code (&sym->action_props); |
| 645 } |
| 646 |
| 647 /* Convert the grammar into the format described in gram.h. */ |
| 648 packgram (); |
| 649 |
| 650 /* The grammar as a symbol_list is no longer needed. */ |
| 651 symbol_list_free (grammar); |
| 652 } |
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