src/parse-gram.y

   1 %{/* Bison Grammar Parser                             -*- C -*-
   2
   3    Copyright (C) 2002-2012 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <config.h>
  21 #include "system.h"
  22
  23 #include "complain.h"
  24 #include "conflicts.h"
  25 #include "files.h"
  26 #include "getargs.h"
  27 #include "gram.h"
  28 #include "muscle-tab.h"
  29 #include "named-ref.h"
  30 #include "quotearg.h"
  31 #include "reader.h"
  32 #include "symlist.h"
  33 #include "scan-gram.h"
  34 #include "scan-code.h"
  35 #include "xmemdup0.h"
  36
  37 #define YYLLOC_DEFAULT(Current, Rhs, N)  (Current) = lloc_default (Rhs, N)
  38 static YYLTYPE lloc_default (YYLTYPE const *, int);
  39
  40 #define YY_LOCATION_PRINT(File, Loc) \
  41           location_print (File, Loc)
  42
  43 static void version_check (location const *loc, char const *version);
  44
  45 /* Request detailed syntax error messages, and pass them to GRAM_ERROR.
  46    FIXME: depends on the undocumented availability of YYLLOC.  */
  47 #undef  yyerror
  48 #define yyerror(Msg) \
  49         gram_error (&yylloc, Msg)
  50 static void gram_error (location const *, char const *);
  51
  52 static char const *char_name (char);
  53 %}
  54
  55 %code
  56 {
  57   static int current_prec = 0;
  58   static location current_lhs_location;
  59   static named_ref *current_lhs_named_ref;
  60   static symbol *current_lhs_symbol;
  61   static symbol_class current_class = unknown_sym;
  62   static uniqstr current_type = NULL;
  63
  64   /** Set the new current left-hand side symbol, possibly common
  65    * to several right-hand side parts of rule.
  66    */
  67   static
  68   void
  69   current_lhs(symbol *sym, location loc, named_ref *ref)
  70   {
  71     current_lhs_symbol = sym;
  72     current_lhs_location = loc;
  73     /* In order to simplify memory management, named references for lhs
  74        are always assigned by deep copy into the current symbol_list
  75        node.  This is because a single named-ref in the grammar may
  76        result in several uses when the user factors lhs between several
  77        rules using "|".  Therefore free the parser's original copy.  */
  78     free (current_lhs_named_ref);
  79     current_lhs_named_ref = ref;
  80   }
  81
  82   #define YYTYPE_INT16 int_fast16_t
  83   #define YYTYPE_INT8 int_fast8_t
  84   #define YYTYPE_UINT16 uint_fast16_t
  85   #define YYTYPE_UINT8 uint_fast8_t
  86 }
  87
  88 %debug
  89 %verbose
  90 %defines
  91 %locations
  92 %pure-parser
  93 %define parse.error "verbose"
  94 %define parse.lac full
  95 %name-prefix="gram_"
  96 %expect 0
  97
  98 %initial-action
  99 {
 100   /* Bison's grammar can initial empty locations, hence a default
 101      location is needed. */
 102   boundary_set (&@$.start, current_file, 1, 1);
 103   boundary_set (&@$.end, current_file, 1, 1);
 104 }
 105
 106 %union
 107 {
 108   assoc assoc;
 109   char *code;
 110   char const *chars;
 111   int integer;
 112   named_ref *named_ref;
 113   symbol *symbol;
 114   symbol_list *list;
 115   uniqstr uniqstr;
 116   unsigned char character;
 117 };
 118
 119 /* Define the tokens together with their human representation.  */
 120 %token GRAM_EOF 0 "end of file"
 121 %token STRING     "string"
 122 %token INT        "integer"
 123
 124 %token PERCENT_TOKEN       "%token"
 125 %token PERCENT_NTERM       "%nterm"
 126
 127 %token PERCENT_TYPE        "%type"
 128 %token PERCENT_DESTRUCTOR  "%destructor"
 129 %token PERCENT_PRINTER     "%printer"
 130
 131 %token PERCENT_LEFT        "%left"
 132 %token PERCENT_RIGHT       "%right"
 133 %token PERCENT_NONASSOC    "%nonassoc"
 134 %token PERCENT_PRECEDENCE  "%precedence"
 135
 136 %token PERCENT_PREC          "%prec"
 137 %token PERCENT_DPREC         "%dprec"
 138 %token PERCENT_MERGE         "%merge"
 139
 140 /*----------------------.
 141 | Global Declarations.  |
 142 `----------------------*/
 143
 144 %token
 145   PERCENT_CODE            "%code"
 146   PERCENT_DEFAULT_PREC    "%default-prec"
 147   PERCENT_DEFINE          "%define"
 148   PERCENT_DEFINES         "%defines"
 149   PERCENT_ERROR_VERBOSE   "%error-verbose"
 150   PERCENT_EXPECT          "%expect"
 151   PERCENT_EXPECT_RR       "%expect-rr"
 152   PERCENT_FLAG            "%<flag>"
 153   PERCENT_FILE_PREFIX     "%file-prefix"
 154   PERCENT_GLR_PARSER      "%glr-parser"
 155   PERCENT_INITIAL_ACTION  "%initial-action"
 156   PERCENT_LANGUAGE        "%language"
 157   PERCENT_NAME_PREFIX     "%name-prefix"
 158   PERCENT_NO_DEFAULT_PREC "%no-default-prec"
 159   PERCENT_NO_LINES        "%no-lines"
 160   PERCENT_NONDETERMINISTIC_PARSER
 161                           "%nondeterministic-parser"
 162   PERCENT_OUTPUT          "%output"
 163   PERCENT_REQUIRE         "%require"
 164   PERCENT_SKELETON        "%skeleton"
 165   PERCENT_START           "%start"
 166   PERCENT_TOKEN_TABLE     "%token-table"
 167   PERCENT_VERBOSE         "%verbose"
 168   PERCENT_YACC            "%yacc"
 169 ;
 170
 171 %token BRACED_CODE     "{...}"
 172 %token BRACED_PREDICATE "%?{...}"
 173 %token BRACKETED_ID    "[identifier]"
 174 %token CHAR            "char"
 175 %token EPILOGUE        "epilogue"
 176 %token EQUAL           "="
 177 %token ID              "identifier"
 178 %token ID_COLON        "identifier:"
 179 %token PERCENT_PERCENT "%%"
 180 %token PIPE            "|"
 181 %token PROLOGUE        "%{...%}"
 182 %token SEMICOLON       ";"
 183 %token TAG             "<tag>"
 184 %token TAG_ANY         "<*>"
 185 %token TAG_NONE        "<>"
 186
 187 %type <character> CHAR
 188 %printer { fputs (char_name ($$), stderr); } CHAR
 189
 190 /* braceless is not to be used for rule or symbol actions, as it
 191    calls code_props_plain_init.  */
 192 %type <chars> STRING "%{...%}" EPILOGUE braceless content.opt
 193 %type <code> "{...}" "%?{...}"
 194 %printer { fputs (quotearg_style (c_quoting_style, $$), stderr); }
 195          STRING
 196 %printer { fprintf (stderr, "{\n%s\n}", $$); }
 197          braceless content.opt "{...}" "%{...%}" EPILOGUE
 198
 199 %type <uniqstr> BRACKETED_ID ID ID_COLON PERCENT_FLAG TAG variable
 200 %printer { fputs ($$, stderr); } <uniqstr>
 201 %printer { fprintf (stderr, "[%s]", $$); } BRACKETED_ID
 202 %printer { fprintf (stderr, "%s:", $$); } ID_COLON
 203 %printer { fprintf (stderr, "%%%s", $$); } PERCENT_FLAG
 204 %printer { fprintf (stderr, "<%s>", $$); } TAG
 205
 206 %type <integer> INT
 207 %printer { fprintf (stderr, "%d", $$); } <integer>
 208
 209 %type <symbol> id id_colon string_as_id symbol symbol.prec
 210 %printer { fprintf (stderr, "%s", $$->tag); } <symbol>
 211 %printer { fprintf (stderr, "%s:", $$->tag); } id_colon
 212
 213 %type <assoc> precedence_declarator
 214 %type <list>  symbols.1 symbols.prec generic_symlist generic_symlist_item
 215 %type <named_ref> named_ref.opt
 216
 217 /*---------.
 218 | %param.  |
 219 `---------*/
 220 %code requires
 221 {
 222 # ifndef PARAM_TYPE
 223 #  define PARAM_TYPE
 224   typedef enum
 225   {
 226     param_none   = 0,
 227     param_lex    = 1 << 0,
 228     param_parse  = 1 << 1,
 229     param_both   = param_lex | param_parse
 230   } param_type;
 231 # endif
 232 };
 233 %code
 234 {
 235   /** Add a lex-param and/or a parse-param.
 236    *
 237    * \param type  where to push this formal argument.
 238    * \param decl  the formal argument.  Destroyed.
 239    * \param loc   the location in the source.
 240    */
 241   static void add_param (param_type type, char *decl, location loc);
 242   static param_type current_param = param_none;
 243 };
 244 %union
 245 {
 246   param_type param;
 247 }
 248 %token <param> PERCENT_PARAM "%param";
 249 %printer
 250 {
 251   switch ($$)
 252     {
 253 #define CASE(In, Out)                                           \
 254       case param_ ## In: fputs ("%" #Out, stderr); break
 255       CASE(lex,   lex-param);
 256       CASE(parse, parse-param);
 257       CASE(both,  param);
 258 #undef CASE
 259       case param_none: aver (false); break;
 260     }
 261 } <param>;
 262
 263
 264                      /*==========\
 265                      | Grammar.  |
 266                      \==========*/
 267 %%
 268
 269 input:
 270   prologue_declarations "%%" grammar epilogue.opt
 271 ;
 272
 273
 274         /*------------------------------------.
 275         | Declarations: before the first %%.  |
 276         `------------------------------------*/
 277
 278 prologue_declarations:
 279   /* Nothing */
 280 | prologue_declarations prologue_declaration
 281 ;
 282
 283 prologue_declaration:
 284   grammar_declaration
 285 | "%{...%}"
 286     {
 287       code_props plain_code;
 288       code_props_plain_init (&plain_code, $1, @1);
 289       code_props_translate_code (&plain_code);
 290       gram_scanner_last_string_free ();
 291       muscle_code_grow (union_seen ? "post_prologue" : "pre_prologue",
 292                         plain_code.code, @1);
 293       code_scanner_last_string_free ();
 294     }
 295 | "%<flag>"
 296     {
 297       muscle_percent_define_ensure ($1, @1, true);
 298     }
 299 | "%define" variable content.opt
 300     {
 301       muscle_percent_define_insert ($2, @2, $3,
 302                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
 303     }
 304 | "%defines"                       { defines_flag = true; }
 305 | "%defines" STRING
 306     {
 307       defines_flag = true;
 308       spec_defines_file = xstrdup ($2);
 309     }
 310 | "%error-verbose"
 311     {
 312       muscle_percent_define_insert ("parse.error", @1, "verbose",
 313                                     MUSCLE_PERCENT_DEFINE_GRAMMAR_FILE);
 314     }
 315 | "%expect" INT                    { expected_sr_conflicts = $2; }
 316 | "%expect-rr" INT                 { expected_rr_conflicts = $2; }
 317 | "%file-prefix" STRING            { spec_file_prefix = $2; }
 318 | "%file-prefix" "=" STRING        { spec_file_prefix = $3; } /* deprecated */
 319 | "%glr-parser"
 320     {
 321       nondeterministic_parser = true;
 322       glr_parser = true;
 323     }
 324 | "%initial-action" "{...}"
 325     {
 326       code_props action;
 327       code_props_symbol_action_init (&action, $2, @2);
 328       code_props_translate_code (&action);
 329       gram_scanner_last_string_free ();
 330       muscle_code_grow ("initial_action", action.code, @2);
 331       code_scanner_last_string_free ();
 332     }
 333 | "%language" STRING            { language_argmatch ($2, grammar_prio, @1); }
 334 | "%name-prefix" STRING         { spec_name_prefix = $2; }
 335 | "%name-prefix" "=" STRING     { spec_name_prefix = $3; } /* deprecated */
 336 | "%no-lines"                   { no_lines_flag = true; }
 337 | "%nondeterministic-parser"    { nondeterministic_parser = true; }
 338 | "%output" STRING              { spec_outfile = $2; }
 339 | "%output" "=" STRING          { spec_outfile = $3; }  /* deprecated */
 340 | "%param" { current_param = $1; } params { current_param = param_none; }
 341 | "%require" STRING             { version_check (&@2, $2); }
 342 | "%skeleton" STRING
 343     {
 344       char const *skeleton_user = $2;
 345       if (strchr (skeleton_user, '/'))
 346         {
 347           size_t dir_length = strlen (current_file);
 348           char *skeleton_build;
 349           while (dir_length && current_file[dir_length - 1] != '/')
 350             --dir_length;
 351           while (dir_length && current_file[dir_length - 1] == '/')
 352             --dir_length;
 353           skeleton_build =
 354             xmalloc (dir_length + 1 + strlen (skeleton_user) + 1);
 355           if (dir_length > 0)
 356             {
 357               memcpy (skeleton_build, current_file, dir_length);
 358               skeleton_build[dir_length++] = '/';
 359             }
 360           strcpy (skeleton_build + dir_length, skeleton_user);
 361           skeleton_user = uniqstr_new (skeleton_build);
 362           free (skeleton_build);
 363         }
 364       skeleton_arg (skeleton_user, grammar_prio, @1);
 365     }
 366 | "%token-table"                { token_table_flag = true; }
 367 | "%verbose"                    { report_flag |= report_states; }
 368 | "%yacc"                       { yacc_flag = true; }
 369 | /*FIXME: Err?  What is this horror doing here? */ ";"
 370 ;
 371
 372 params:
 373    params "{...}"  { add_param (current_param, $2, @2); }
 374 | "{...}"          { add_param (current_param, $1, @1); }
 375 ;
 376
 377
 378 /*----------------------.
 379 | grammar_declaration.  |
 380 `----------------------*/
 381
 382 grammar_declaration:
 383   precedence_declaration
 384 | symbol_declaration
 385 | "%start" symbol
 386     {
 387       grammar_start_symbol_set ($2, @2);
 388     }
 389 | "%destructor" "{...}" generic_symlist
 390     {
 391       symbol_list *list;
 392       for (list = $3; list; list = list->next)
 393         symbol_list_destructor_set (list, $2, @2);
 394       symbol_list_free ($3);
 395     }
 396 | "%printer" "{...}" generic_symlist
 397     {
 398       symbol_list *list;
 399       for (list = $3; list; list = list->next)
 400         symbol_list_printer_set (list, $2, @2);
 401       symbol_list_free ($3);
 402     }
 403 | "%default-prec"
 404     {
 405       default_prec = true;
 406     }
 407 | "%no-default-prec"
 408     {
 409       default_prec = false;
 410     }
 411 | "%code" braceless
 412     {
 413       /* Do not invoke muscle_percent_code_grow here since it invokes
 414          muscle_user_name_list_grow.  */
 415       muscle_code_grow ("percent_code()", $2, @2);
 416       code_scanner_last_string_free ();
 417     }
 418 | "%code" ID braceless
 419     {
 420       muscle_percent_code_grow ($2, @2, $3, @3);
 421       code_scanner_last_string_free ();
 422     }
 423 ;
 424
 425
 426 /*---------.
 427 | %union.  |
 428 `---------*/
 429
 430 %token PERCENT_UNION "%union";
 431
 432 union_name:
 433   /* Nothing. */ {}
 434 | ID             { muscle_code_grow ("union_name", $1, @1); }
 435 ;
 436
 437 grammar_declaration:
 438   "%union" union_name braceless
 439     {
 440       union_seen = true;
 441       muscle_code_grow ("stype", $3, @3);
 442       code_scanner_last_string_free ();
 443     }
 444 ;
 445
 446
 447
 448
 449 symbol_declaration:
 450   "%nterm" { current_class = nterm_sym; } symbol_defs.1
 451     {
 452       current_class = unknown_sym;
 453       current_type = NULL;
 454     }
 455 | "%token" { current_class = token_sym; } symbol_defs.1
 456     {
 457       current_class = unknown_sym;
 458       current_type = NULL;
 459     }
 460 | "%type" TAG symbols.1
 461     {
 462       symbol_list *list;
 463       tag_seen = true;
 464       for (list = $3; list; list = list->next)
 465         symbol_type_set (list->content.sym, $2, @2);
 466       symbol_list_free ($3);
 467     }
 468 ;
 469
 470 precedence_declaration:
 471   precedence_declarator tag.opt symbols.prec
 472     {
 473       symbol_list *list;
 474       ++current_prec;
 475       for (list = $3; list; list = list->next)
 476         {
 477           symbol_type_set (list->content.sym, current_type, @2);
 478           symbol_precedence_set (list->content.sym, current_prec, $1, @1);
 479         }
 480       symbol_list_free ($3);
 481       current_type = NULL;
 482     }
 483 ;
 484
 485 precedence_declarator:
 486   "%left"       { $$ = left_assoc; }
 487 | "%right"      { $$ = right_assoc; }
 488 | "%nonassoc"   { $$ = non_assoc; }
 489 | "%precedence" { $$ = precedence_assoc; }
 490 ;
 491
 492 tag.opt:
 493   /* Nothing. */ { current_type = NULL; }
 494 | TAG            { current_type = $1; tag_seen = true; }
 495 ;
 496
 497 /* Just like symbols.1 but accept INT for the sake of POSIX.  */
 498 symbols.prec:
 499   symbol.prec
 500     { $$ = symbol_list_sym_new ($1, @1); }
 501 | symbols.prec symbol.prec
 502     { $$ = symbol_list_prepend ($1, symbol_list_sym_new ($2, @2)); }
 503 ;
 504
 505 symbol.prec:
 506     symbol { $$ = $1; }
 507   | symbol INT { $$ = $1; symbol_user_token_number_set ($1, $2, @2); }
 508   ;
 509
 510 /* One or more symbols to be %typed. */
 511 symbols.1:
 512   symbol
 513     { $$ = symbol_list_sym_new ($1, @1); }
 514 | symbols.1 symbol
 515     { $$ = symbol_list_prepend ($1, symbol_list_sym_new ($2, @2)); }
 516 ;
 517
 518 generic_symlist:
 519   generic_symlist_item { $$ = $1; }
 520 | generic_symlist generic_symlist_item { $$ = symbol_list_prepend ($1, $2); }
 521 ;
 522
 523 generic_symlist_item:
 524   symbol    { $$ = symbol_list_sym_new ($1, @1); }
 525 | TAG       { $$ = symbol_list_type_new ($1, @1); }
 526 | "<*>"     { $$ = symbol_list_default_tagged_new (@1); }
 527 | "<>"      { $$ = symbol_list_default_tagless_new (@1); }
 528 ;
 529
 530 /* One token definition.  */
 531 symbol_def:
 532   TAG
 533      {
 534        current_type = $1;
 535        tag_seen = true;
 536      }
 537 | id
 538      {
 539        symbol_class_set ($1, current_class, @1, true);
 540        symbol_type_set ($1, current_type, @1);
 541      }
 542 | id INT
 543     {
 544       symbol_class_set ($1, current_class, @1, true);
 545       symbol_type_set ($1, current_type, @1);
 546       symbol_user_token_number_set ($1, $2, @2);
 547     }
 548 | id string_as_id
 549     {
 550       symbol_class_set ($1, current_class, @1, true);
 551       symbol_type_set ($1, current_type, @1);
 552       symbol_make_alias ($1, $2, @$);
 553     }
 554 | id INT string_as_id
 555     {
 556       symbol_class_set ($1, current_class, @1, true);
 557       symbol_type_set ($1, current_type, @1);
 558       symbol_user_token_number_set ($1, $2, @2);
 559       symbol_make_alias ($1, $3, @$);
 560     }
 561 ;
 562
 563 /* One or more symbol definitions. */
 564 symbol_defs.1:
 565   symbol_def
 566 | symbol_defs.1 symbol_def
 567 ;
 568
 569
 570         /*------------------------------------------.
 571         | The grammar section: between the two %%.  |
 572         `------------------------------------------*/
 573
 574 grammar:
 575   rules_or_grammar_declaration
 576 | grammar rules_or_grammar_declaration
 577 ;
 578
 579 /* As a Bison extension, one can use the grammar declarations in the
 580    body of the grammar.  */
 581 rules_or_grammar_declaration:
 582   rules
 583 | grammar_declaration ";"
 584 | error ";"
 585     {
 586       yyerrok;
 587     }
 588 ;
 589
 590 rules:
 591   id_colon named_ref.opt { current_lhs ($1, @1, $2); } rhses.1
 592   {
 593     /* Free the current lhs. */
 594     current_lhs (0, @1, 0);
 595   }
 596 ;
 597
 598 rhses.1:
 599   rhs                { grammar_current_rule_end (@1); }
 600 | rhses.1 "|" rhs    { grammar_current_rule_end (@3); }
 601 | rhses.1 ";"
 602 ;
 603
 604 rhs:
 605   /* Nothing.  */
 606     { grammar_current_rule_begin (current_lhs_symbol, current_lhs_location,
 607                                   current_lhs_named_ref); }
 608 | rhs symbol named_ref.opt
 609     { grammar_current_rule_symbol_append ($2, @2, $3); }
 610 | rhs "{...}" named_ref.opt
 611     { grammar_current_rule_action_append ($2, @2, $3, false); }
 612 | rhs "%?{...}"
 613     { grammar_current_rule_action_append ($2, @2, NULL, true); }
 614 | rhs "%prec" symbol
 615     { grammar_current_rule_prec_set ($3, @3); }
 616 | rhs "%dprec" INT
 617     { grammar_current_rule_dprec_set ($3, @3); }
 618 | rhs "%merge" TAG
 619     { grammar_current_rule_merge_set ($3, @3); }
 620 ;
 621
 622 named_ref.opt:
 623   /* Nothing. */ { $$ = 0; }
 624 |
 625   BRACKETED_ID   { $$ = named_ref_new($1, @1); }
 626 ;
 627
 628 /*---------------------------.
 629 | variable and content.opt.  |
 630 `---------------------------*/
 631
 632 /* The STRING form of variable is deprecated and is not M4-friendly.
 633    For example, M4 fails for `%define "[" "value"'.  */
 634 variable:
 635   ID
 636 | STRING { $$ = uniqstr_new ($1); }
 637 ;
 638
 639 /* Some content or empty by default. */
 640 content.opt:
 641   /* Nothing. */   { $$ = ""; }
 642 | ID { $$ = $1; }
 643 | STRING
 644 ;
 645
 646
 647 /*------------.
 648 | braceless.  |
 649 `------------*/
 650
 651 braceless:
 652   "{...}"
 653     {
 654       code_props plain_code;
 655       $1[strlen ($1) - 1] = '\n';
 656       code_props_plain_init (&plain_code, $1+1, @1);
 657       code_props_translate_code (&plain_code);
 658       gram_scanner_last_string_free ();
 659       $$ = plain_code.code;
 660     }
 661 ;
 662
 663
 664 /*--------------.
 665 | Identifiers.  |
 666 `--------------*/
 667
 668 /* Identifiers are returned as uniqstr values by the scanner.
 669    Depending on their use, we may need to make them genuine symbols.  */
 670
 671 id:
 672   ID
 673     { $$ = symbol_from_uniqstr ($1, @1); }
 674 | CHAR
 675     {
 676       $$ = symbol_get (char_name ($1), @1);
 677       symbol_class_set ($$, token_sym, @1, false);
 678       symbol_user_token_number_set ($$, $1, @1);
 679     }
 680 ;
 681
 682 id_colon:
 683   ID_COLON { $$ = symbol_from_uniqstr ($1, @1); }
 684 ;
 685
 686
 687 symbol:
 688   id
 689 | string_as_id
 690 ;
 691
 692 /* A string used as an ID: quote it.  */
 693 string_as_id:
 694   STRING
 695     {
 696       $$ = symbol_get (quotearg_style (c_quoting_style, $1), @1);
 697       symbol_class_set ($$, token_sym, @1, false);
 698     }
 699 ;
 700
 701 epilogue.opt:
 702   /* Nothing.  */
 703 | "%%" EPILOGUE
 704     {
 705       code_props plain_code;
 706       code_props_plain_init (&plain_code, $2, @2);
 707       code_props_translate_code (&plain_code);
 708       gram_scanner_last_string_free ();
 709       muscle_code_grow ("epilogue", plain_code.code, @2);
 710       code_scanner_last_string_free ();
 711     }
 712 ;
 713
 714 %%
 715
 716
 717 /* Return the location of the left-hand side of a rule whose
 718    right-hand side is RHS[1] ... RHS[N].  Ignore empty nonterminals in
 719    the right-hand side, and return an empty location equal to the end
 720    boundary of RHS[0] if the right-hand side is empty.  */
 721
 722 static YYLTYPE
 723 lloc_default (YYLTYPE const *rhs, int n)
 724 {
 725   int i;
 726   YYLTYPE loc;
 727
 728   /* SGI MIPSpro 7.4.1m miscompiles "loc.start = loc.end = rhs[n].end;".
 729      The bug is fixed in 7.4.2m, but play it safe for now.  */
 730   loc.start = rhs[n].end;
 731   loc.end = rhs[n].end;
 732
 733   /* Ignore empty nonterminals the start of the right-hand side.
 734      Do not bother to ignore them at the end of the right-hand side,
 735      since empty nonterminals have the same end as their predecessors.  */
 736   for (i = 1; i <= n; i++)
 737     if (! equal_boundaries (rhs[i].start, rhs[i].end))
 738       {
 739         loc.start = rhs[i].start;
 740         break;
 741       }
 742
 743   return loc;
 744 }
 745
 746
 747 static void
 748 add_param (param_type type, char *decl, location loc)
 749 {
 750   static char const alphanum[26 + 26 + 1 + 10] =
 751     "abcdefghijklmnopqrstuvwxyz"
 752     "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 753     "_"
 754     "0123456789";
 755
 756   char const *name_start = NULL;
 757   {
 758     char *p;
 759     /* Stop on last actual character.  */
 760     for (p = decl; p[1]; p++)
 761       if ((p == decl
 762            || ! memchr (alphanum, p[-1], sizeof alphanum))
 763           && memchr (alphanum, p[0], sizeof alphanum - 10))
 764         name_start = p;
 765
 766     /* Strip the surrounding '{' and '}', and any blanks just inside
 767        the braces.  */
 768     while (*--p == ' ' || *p == '\t')
 769       continue;
 770     p[1] = '\0';
 771     while (*++decl == ' ' || *decl == '\t')
 772       continue;
 773   }
 774
 775   if (! name_start)
 776     complain_at (loc, _("missing identifier in parameter declaration"));
 777   else
 778     {
 779       char *name = xmemdup0 (name_start, strspn (name_start, alphanum));
 780       if (type & param_lex)
 781         muscle_pair_list_grow ("lex_param", decl, name);
 782       if (type & param_parse)
 783         muscle_pair_list_grow ("parse_param", decl, name);
 784       free (name);
 785     }
 786
 787   gram_scanner_last_string_free ();
 788 }
 789
 790
 791 static void
 792 version_check (location const *loc, char const *version)
 793 {
 794   if (strverscmp (version, PACKAGE_VERSION) > 0)
 795     {
 796       complain_at (*loc, "require bison %s, but have %s",
 797                    version, PACKAGE_VERSION);
 798       exit (EX_MISMATCH);
 799     }
 800 }
 801
 802 static void
 803 gram_error (location const *loc, char const *msg)
 804 {
 805   complain_at (*loc, "%s", msg);
 806 }
 807
 808 char const *
 809 token_name (int type)
 810 {
 811   return yytname[YYTRANSLATE (type)];
 812 }
 813
 814 static char const *
 815 char_name (char c)
 816 {
 817   if (c == '\'')
 818     return "'\\''";
 819   else
 820     {
 821       char buf[4];
 822       buf[0] = '\''; buf[1] = c; buf[2] = '\''; buf[3] = '\0';
 823       return quotearg_style (escape_quoting_style, buf);
 824     }
 825 }