src/scan-code.l

   1 /* Bison Action Scanner                             -*- C -*-
   2
   3    Copyright (C) 2006-2012 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 %option debug nodefault noinput nounput noyywrap never-interactive
  21 %option prefix="code_" outfile="lex.yy.c"
  22
  23 %{
  24 /* Work around a bug in flex 2.5.31.  See Debian bug 333231
  25    <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>.  */
  26 #undef code_wrap
  27 #define code_wrap() 1
  28
  29 #define FLEX_PREFIX(Id) code_ ## Id
  30 #include "flex-scanner.h"
  31
  32 #include "complain.h"
  33 #include "reader.h"
  34 #include "getargs.h"
  35 #include "scan-code.h"
  36 #include "symlist.h"
  37
  38 #include <c-ctype.h>
  39 #include <get-errno.h>
  40 #include <quote.h>
  41
  42 /* The current calling start condition: SC_RULE_ACTION or
  43    SC_SYMBOL_ACTION. */
  44 # define YY_DECL static char *code_lex (code_props *self, int sc_context)
  45 YY_DECL;
  46
  47 #define YY_USER_ACTION  location_compute (loc, &loc->end, yytext, yyleng);
  48
  49 static char *fetch_type_name (char *cp, char const **type_name,
  50                               location dollar_loc);
  51
  52 static void handle_action_dollar (symbol_list *rule, char *cp,
  53                                   location dollar_loc);
  54 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
  55
  56 /* A string to be pushed to obstack after dollar/at has been handled. */
  57 static char *ref_tail_fields;
  58
  59 static location the_location;
  60 static location *loc = &the_location;
  61
  62 /* A string representing the most recent translation.  */
  63 static char *last_string;
  64
  65 /* True if an untyped $$ or $n was seen.  */
  66 static bool untyped_var_seen;
  67
  68 %}
  69  /* C and C++ comments in code. */
  70 %x SC_COMMENT SC_LINE_COMMENT
  71  /* Strings and characters in code. */
  72 %x SC_STRING SC_CHARACTER
  73  /* Whether in a rule or symbol action.  Specifies the translation
  74     of $ and @.  */
  75 %x SC_RULE_ACTION SC_SYMBOL_ACTION
  76
  77
  78 /* POSIX says that a tag must be both an id and a C union member, but
  79    historically almost any character is allowed in a tag.  We disallow
  80    NUL and newline, as this simplifies our implementation.  */
  81 tag      [^\0\n>]+
  82
  83 /* Zero or more instances of backslash-newline.  Following GCC, allow
  84    white space between the backslash and the newline.  */
  85 splice   (\\[ \f\t\v]*\n)*
  86
  87 /* C style identifier. Must start with letter. Will be used for
  88    named symbol references. Shall be kept synchronized with
  89    scan-gram.l "letter" and "id". */
  90 letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
  91 id        {letter}({letter}|[-0-9])*
  92 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
  93
  94 %%
  95
  96 %{
  97   /* Nesting level of the current code in braces.  */
  98   int braces_level = 0;
  99
 100   /* Whether a semicolon is probably needed.
 101
 102      The heuristic is that a semicolon is not needed after '{', '}',
 103      ';', or a C preprocessor directive, and that whitespaces and
 104      comments do not affect this flag.  Note that '{' does not need a
 105      semicolon because of '{}'.  A semicolon may be needed before a
 106      cpp directive, but don't bother.  */
 107   bool need_semicolon = false;
 108
 109   /* Whether in a C preprocessor directive.  Don't use a start condition
 110      for this because, at the end of strings and comments, we still need
 111      to know whether we're in a directive.  */
 112   bool in_cpp = false;
 113
 114   /* This scanner is special: it is invoked only once, henceforth
 115      is expected to return only once.  This initialization is
 116      therefore done once per action to translate. */
 117   aver (sc_context == SC_SYMBOL_ACTION
 118         || sc_context == SC_RULE_ACTION
 119         || sc_context == INITIAL);
 120   BEGIN sc_context;
 121 %}
 122
 123   /*------------------------------------------------------------.
 124   | Scanning a C comment.  The initial '/ *' is already eaten.  |
 125   `------------------------------------------------------------*/
 126
 127 <SC_COMMENT>
 128 {
 129   "*"{splice}"/"  STRING_GROW; BEGIN sc_context;
 130 }
 131
 132
 133   /*--------------------------------------------------------------.
 134   | Scanning a line comment.  The initial '//' is already eaten.  |
 135   `--------------------------------------------------------------*/
 136
 137 <SC_LINE_COMMENT>
 138 {
 139   "\n"           STRING_GROW; BEGIN sc_context;
 140   {splice}       STRING_GROW;
 141 }
 142
 143
 144   /*--------------------------------------------.
 145   | Scanning user-code characters and strings.  |
 146   `--------------------------------------------*/
 147
 148 <SC_CHARACTER,SC_STRING>
 149 {
 150   {splice}|\\{splice}.  STRING_GROW;
 151 }
 152
 153 <SC_CHARACTER>
 154 {
 155   "'"           STRING_GROW; BEGIN sc_context;
 156 }
 157
 158 <SC_STRING>
 159 {
 160   "\""          STRING_GROW; BEGIN sc_context;
 161 }
 162
 163
 164 <SC_RULE_ACTION,SC_SYMBOL_ACTION>
 165 {
 166   "'" {
 167     STRING_GROW;
 168     BEGIN SC_CHARACTER;
 169     need_semicolon = true;
 170   }
 171   "\"" {
 172     STRING_GROW;
 173     BEGIN SC_STRING;
 174     need_semicolon = true;
 175   }
 176   "/"{splice}"*" {
 177     STRING_GROW;
 178     BEGIN SC_COMMENT;
 179   }
 180   "/"{splice}"/" {
 181     STRING_GROW;
 182     BEGIN SC_LINE_COMMENT;
 183   }
 184 }
 185
 186 <SC_RULE_ACTION>
 187 {
 188   "$"("<"{tag}">")?{ref}  {
 189     ref_tail_fields = NULL;
 190     handle_action_dollar (self->rule, yytext, *loc);
 191     if (ref_tail_fields)
 192       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 193     need_semicolon = true;
 194   }
 195   "@"{ref} {
 196     ref_tail_fields = NULL;
 197     handle_action_at (self->rule, yytext, *loc);
 198     if (ref_tail_fields)
 199       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 200     need_semicolon = true;
 201   }
 202   "$"  {
 203     warn_at (*loc, _("stray '$'"));
 204     obstack_sgrow (&obstack_for_string, "$][");
 205     need_semicolon = true;
 206   }
 207   "@"  {
 208     warn_at (*loc, _("stray '@'"));
 209     obstack_sgrow (&obstack_for_string, "@@");
 210     need_semicolon = true;
 211   }
 212   "["  {
 213     obstack_sgrow (&obstack_for_string, "@{");
 214     need_semicolon = true;
 215   }
 216   "]"  {
 217     obstack_sgrow (&obstack_for_string, "@}");
 218     need_semicolon = true;
 219   }
 220
 221   ";"  STRING_GROW;                 need_semicolon = false;
 222   "{"  STRING_GROW; ++braces_level; need_semicolon = false;
 223   "}"  {
 224     bool outer_brace = --braces_level == 0;
 225
 226     /* As an undocumented Bison extension, append ';' before the last
 227        brace in braced code, so that the user code can omit trailing
 228        ';'.  But do not append ';' if emulating Yacc, since Yacc does
 229        not append one.  */
 230     if (outer_brace && !yacc_flag && language_prio == default_prio
 231         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
 232       {
 233         warn_at (*loc, _("a ';' might be needed at the end of action code"));
 234         warn_at (*loc, _("future versions of Bison will not add the ';'"));
 235         obstack_1grow (&obstack_for_string, ';');
 236       }
 237
 238     STRING_GROW;
 239     need_semicolon = false;
 240   }
 241
 242   /* Preprocessing directives should only be recognized at the beginning
 243      of lines, allowing whitespace including comments, but in C/C++,
 244      '#' can only be the start of preprocessor directives or within
 245      '#define' directives anyway, so don't bother with begin of line.  */
 246   "#"       STRING_GROW; in_cpp = true;
 247
 248   {splice}  STRING_GROW;
 249   [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;
 250   [ \t\f]   STRING_GROW;
 251
 252   /* YYFAIL is undocumented and was formally deprecated in Bison
 253      2.4.2.  */
 254   YYFAIL {
 255     STRING_GROW; need_semicolon = true;
 256     warn_at (*loc, _("use of YYFAIL, which is deprecated and will be"
 257                      " removed"));
 258   }
 259
 260   /* The sole purpose of this is to make sure identifiers that merely
 261      contain YYFAIL don't produce the above warning.  */
 262   [A-Za-z_][0-9A-Za-z_]* STRING_GROW; need_semicolon = true;
 263
 264   . STRING_GROW; need_semicolon = true;
 265 }
 266
 267 <SC_SYMBOL_ACTION>
 268 {
 269   "$"("<"{tag}">")?"$" {
 270     const char *type_name = NULL;
 271     fetch_type_name (yytext + 1, &type_name, *loc)[-1] = 0;
 272     obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar(");
 273     obstack_quote (&obstack_for_string, type_name);
 274     obstack_sgrow (&obstack_for_string, ")[");
 275     self->is_value_used = true;
 276   }
 277   "@$" {
 278     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
 279     locations_flag = true;
 280   }
 281 }
 282
 283
 284   /*-----------------------------------------.
 285   | Escape M4 quoting characters in C code.  |
 286   `-----------------------------------------*/
 287
 288 <*>
 289 {
 290   \$    obstack_sgrow (&obstack_for_string, "$][");
 291   \@    obstack_sgrow (&obstack_for_string, "@@");
 292   \[    obstack_sgrow (&obstack_for_string, "@{");
 293   \]    obstack_sgrow (&obstack_for_string, "@}");
 294 }
 295
 296   /*-----------------------------------------------------.
 297   | By default, grow the string obstack with the input.  |
 298   `-----------------------------------------------------*/
 299
 300 <*>.|\n STRING_GROW;
 301
 302  /* End of processing. */
 303 <*><<EOF>>       {
 304                    STRING_FINISH;
 305                    return last_string;
 306                  }
 307
 308 %%
 309
 310 static inline bool
 311 is_dot_or_dash (char ch)
 312 {
 313   return ch == '.' || ch == '-';
 314 }
 315
 316 static inline bool
 317 contains_dot_or_dash (const char* p)
 318 {
 319   for (; *p; ++p)
 320     if (is_dot_or_dash (*p))
 321       return true;
 322   return false;
 323 }
 324
 325 /* Defines a variant of a symbolic name resolution. */
 326 typedef struct
 327 {
 328   /* Index in symbol list. */
 329   unsigned symbol_index;
 330
 331   /* Matched symbol id and loc. */
 332   uniqstr id;
 333   location loc;
 334
 335   /* Hiding named reference. */
 336   named_ref* hidden_by;
 337
 338   /* Error flags. May contain zero (no errors) or
 339      a combination of VARIANT_* values. */
 340   unsigned err;
 341 } variant;
 342
 343 /* Set when the variant refers to a symbol hidden
 344    by an explicit symbol reference. */
 345 #define VARIANT_HIDDEN (1 << 0)
 346
 347 /* Set when the variant refers to a symbol containing
 348    dots or dashes. Will require explicit bracketing. */
 349 #define VARIANT_BAD_BRACKETING (1 << 1)
 350
 351 /* Set when the variant refers to a symbol which is
 352    not visible from current midrule. */
 353 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 354
 355 static variant *variant_table = NULL;
 356 static unsigned variant_table_size = 0;
 357 static unsigned variant_count = 0;
 358
 359 static variant *
 360 variant_table_grow (void)
 361 {
 362   ++variant_count;
 363   if (variant_count > variant_table_size)
 364     {
 365       while (variant_count > variant_table_size)
 366         variant_table_size = 2 * variant_table_size + 3;
 367       variant_table = xnrealloc (variant_table, variant_table_size,
 368                                  sizeof *variant_table);
 369     }
 370   return &variant_table[variant_count - 1];
 371 }
 372
 373 static void
 374 variant_table_free (void)
 375 {
 376   free (variant_table);
 377   variant_table = NULL;
 378   variant_table_size = variant_count = 0;
 379 }
 380
 381 static char *
 382 find_prefix_end (const char *prefix, char *begin, char *end)
 383 {
 384   char *ptr = begin;
 385
 386   for (; *prefix && ptr != end; ++prefix, ++ptr)
 387     if (*prefix != *ptr)
 388       return 0;
 389
 390   if (*prefix)
 391     return 0;
 392
 393   return ptr;
 394 }
 395
 396 static variant *
 397 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 398              char *cp, char *cp_end, bool explicit_bracketing)
 399 {
 400   char *prefix_end;
 401
 402   prefix_end = find_prefix_end (id, cp, cp_end);
 403   if (prefix_end &&
 404       (prefix_end == cp_end ||
 405        (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
 406     {
 407       variant *r = variant_table_grow ();
 408       r->symbol_index = symbol_index;
 409       r->id = id;
 410       r->loc = id_loc;
 411       r->hidden_by = NULL;
 412       r->err = 0;
 413       return r;
 414     }
 415   else
 416     return NULL;
 417 }
 418
 419 static const char *
 420 get_at_spec (unsigned symbol_index)
 421 {
 422   static char at_buf[20];
 423   if (symbol_index == 0)
 424     strcpy (at_buf, "$$");
 425   else
 426     snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
 427   return at_buf;
 428 }
 429
 430 static void
 431 show_sub_messages (const char* cp, bool explicit_bracketing,
 432                    int midrule_rhs_index, char dollar_or_at,
 433                    bool is_warning, unsigned indent)
 434 {
 435   unsigned i;
 436
 437   for (i = 0; i < variant_count; ++i)
 438     {
 439       const variant *var = &variant_table[i];
 440       const char *at_spec = get_at_spec (var->symbol_index);
 441
 442       if (var->err == 0)
 443         {
 444           if (is_warning)
 445             warn_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 446                             dollar_or_at, var->id, at_spec);
 447           else
 448             complain_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 449                                 dollar_or_at, var->id, at_spec);
 450         }
 451       else
 452         {
 453           static struct obstack msg_buf;
 454           const char *tail = explicit_bracketing ? "" :
 455             cp + strlen (var->id);
 456           const char *id = var->hidden_by ? var->hidden_by->id :
 457             var->id;
 458           location id_loc = var->hidden_by ? var->hidden_by->loc :
 459             var->loc;
 460
 461           /* Create the explanation message. */
 462           obstack_init (&msg_buf);
 463
 464           obstack_fgrow1 (&msg_buf, _("possibly meant: %c"), dollar_or_at);
 465           if (contains_dot_or_dash (id))
 466             obstack_fgrow1 (&msg_buf, "[%s]", id);
 467           else
 468             obstack_sgrow (&msg_buf, id);
 469           obstack_sgrow (&msg_buf, tail);
 470
 471           if (var->err & VARIANT_HIDDEN)
 472             {
 473               obstack_fgrow1 (&msg_buf, _(", hiding %c"), dollar_or_at);
 474               if (contains_dot_or_dash (var->id))
 475                 obstack_fgrow1 (&msg_buf, "[%s]", var->id);
 476               else
 477                 obstack_sgrow (&msg_buf, var->id);
 478               obstack_sgrow (&msg_buf, tail);
 479             }
 480
 481           obstack_fgrow1 (&msg_buf, _(" at %s"), at_spec);
 482
 483           if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 484             {
 485               const char *format =
 486                 _(", cannot be accessed from mid-rule action at $%d");
 487               obstack_fgrow1 (&msg_buf, format, midrule_rhs_index);
 488             }
 489
 490           obstack_1grow (&msg_buf, '\0');
 491           if (is_warning)
 492             warn_at_indent (id_loc, &indent, "%s",
 493                             (char *) obstack_finish (&msg_buf));
 494           else
 495             complain_at_indent (id_loc, &indent, "%s",
 496                                 (char *) obstack_finish (&msg_buf));
 497           obstack_free (&msg_buf, 0);
 498         }
 499     }
 500 }
 501
 502 /* Returned from "parse_ref" when the reference
 503    is inappropriate. */
 504 #define INVALID_REF (INT_MIN)
 505
 506 /* Returned from "parse_ref" when the reference
 507    points to LHS ($$) of the current rule or midrule. */
 508 #define LHS_REF (INT_MIN + 1)
 509
 510 /* Sub-messages indent. */
 511 #define SUB_INDENT (4)
 512
 513 /* Parse named or positional reference. In case of positional
 514    references, can return negative values for $-n "deep" stack
 515    accesses. */
 516 static long int
 517 parse_ref (char *cp, symbol_list *rule, int rule_length,
 518            int midrule_rhs_index, char *text, location text_loc,
 519            char dollar_or_at)
 520 {
 521   symbol_list *l;
 522   char *cp_end;
 523   bool explicit_bracketing;
 524   unsigned i;
 525   unsigned valid_variants = 0;
 526   unsigned valid_variant_index = 0;
 527
 528   if ('$' == *cp)
 529     return LHS_REF;
 530
 531   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 532     {
 533       long int num = strtol (cp, &cp, 10);
 534       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 535         return num;
 536       else
 537         {
 538           complain_at (text_loc, _("integer out of range: %s"),
 539                        quote (text));
 540           return INVALID_REF;
 541         }
 542     }
 543
 544   if ('[' == *cp)
 545     {
 546       /* Ignore the brackets. */
 547       char *p;
 548       for (p = ++cp; *p != ']'; ++p)
 549         continue;
 550       cp_end = p;
 551
 552       explicit_bracketing = true;
 553     }
 554   else
 555     {
 556       /* Take all characters of the name. */
 557       char* p;
 558       for (p = cp; *p; ++p)
 559         if (is_dot_or_dash (*p))
 560           {
 561             ref_tail_fields = p;
 562             break;
 563           }
 564       for (p = cp; *p; ++p)
 565         continue;
 566       cp_end = p;
 567
 568       explicit_bracketing = false;
 569     }
 570
 571   /* Add all relevant variants. */
 572   {
 573     unsigned symbol_index;
 574     variant_count = 0;
 575     for (symbol_index = 0, l = rule; !symbol_list_null (l);
 576          ++symbol_index, l = l->next)
 577       {
 578         variant *var;
 579         if (l->content_type != SYMLIST_SYMBOL)
 580           continue;
 581
 582         var = variant_add (l->content.sym->tag, l->sym_loc,
 583                            symbol_index, cp, cp_end, explicit_bracketing);
 584         if (var && l->named_ref)
 585           var->hidden_by = l->named_ref;
 586
 587         if (l->named_ref)
 588           variant_add (l->named_ref->id, l->named_ref->loc,
 589                        symbol_index, cp, cp_end, explicit_bracketing);
 590       }
 591   }
 592
 593   /* Check errors. */
 594   for (i = 0; i < variant_count; ++i)
 595     {
 596       variant *var = &variant_table[i];
 597       unsigned symbol_index = var->symbol_index;
 598
 599       /* Check visibility from mid-rule actions. */
 600       if (midrule_rhs_index != 0
 601           && (symbol_index == 0 || midrule_rhs_index < symbol_index))
 602         var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 603
 604       /* Check correct bracketing. */
 605       if (!explicit_bracketing && contains_dot_or_dash (var->id))
 606         var->err |= VARIANT_BAD_BRACKETING;
 607
 608       /* Check using of hidden symbols. */
 609       if (var->hidden_by)
 610         var->err |= VARIANT_HIDDEN;
 611
 612       if (!var->err)
 613         {
 614           valid_variant_index = i;
 615           ++valid_variants;
 616         }
 617     }
 618
 619   switch (valid_variants)
 620     {
 621     case 0:
 622       {
 623         unsigned len = (explicit_bracketing || !ref_tail_fields) ?
 624           cp_end - cp : ref_tail_fields - cp;
 625         unsigned indent = 0;
 626
 627         complain_at_indent (text_loc, &indent, _("invalid reference: %s"),
 628                             quote (text));
 629         indent += SUB_INDENT;
 630         if (len == 0)
 631           {
 632             location sym_loc = text_loc;
 633             sym_loc.start.column += 1;
 634             sym_loc.end = sym_loc.start;
 635             const char *format =
 636               _("syntax error after '%c', expecting integer, letter,"
 637                 " '_', '[', or '$'");
 638             complain_at_indent (sym_loc, &indent, format, dollar_or_at);
 639           }
 640         else if (midrule_rhs_index)
 641           {
 642             const char *format =
 643               _("symbol not found in production before $%d: %.*s");
 644             complain_at_indent (rule->location, &indent, format,
 645                                 midrule_rhs_index, len, cp);
 646           }
 647         else
 648           {
 649             const char *format =
 650               _("symbol not found in production: %.*s");
 651             complain_at_indent (rule->location, &indent, format,
 652                                 len, cp);
 653           }
 654
 655         if (variant_count > 0)
 656           show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 657                              dollar_or_at, false, indent);
 658         return INVALID_REF;
 659       }
 660     case 1:
 661       {
 662         unsigned indent = 0;
 663         if (variant_count > 1)
 664           {
 665             warn_at_indent (text_loc, &indent, _("misleading reference: %s"),
 666                             quote (text));
 667             show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 668                                dollar_or_at, true, indent + SUB_INDENT);
 669           }
 670         {
 671           unsigned symbol_index =
 672             variant_table[valid_variant_index].symbol_index;
 673           return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
 674         }
 675       }
 676     case 2:
 677     default:
 678       {
 679         unsigned indent = 0;
 680         complain_at_indent (text_loc, &indent, _("ambiguous reference: %s"),
 681                             quote (text));
 682         show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 683                            dollar_or_at, false, indent + SUB_INDENT);
 684         return INVALID_REF;
 685       }
 686     }
 687
 688   /* Not reachable. */
 689   return INVALID_REF;
 690 }
 691
 692 /* Keeps track of the maximum number of semantic values to the left of
 693    a handle (those referenced by $0, $-1, etc.) are required by the
 694    semantic actions of this grammar. */
 695 int max_left_semantic_context = 0;
 696
 697
 698 /* If CP points to a typename (i.e., <.*?>), set TYPE_NAME to its
 699    beginning (i.e., after the opening "<", and return the pointer
 700    immediately after it.  */
 701
 702 static
 703 char *
 704 fetch_type_name (char *cp, char const **type_name,
 705                  location dollar_loc)
 706 {
 707   if (*cp == '<')
 708     {
 709       *type_name = ++cp;
 710       while (*cp != '>')
 711         ++cp;
 712
 713       /* The '>' symbol will be later replaced by '\0'. Original
 714          'text' is needed for error messages. */
 715       ++cp;
 716       if (untyped_var_seen)
 717         complain_at (dollar_loc, _("explicit type given in untyped grammar"));
 718       tag_seen = true;
 719     }
 720   return cp;
 721 }
 722
 723 /*------------------------------------------------------------------.
 724 | TEXT is pointing to a wannabee semantic value (i.e., a '$').      |
 725 |                                                                   |
 726 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 727 |                                                                   |
 728 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 729 `------------------------------------------------------------------*/
 730
 731 static void
 732 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 733 {
 734   char const *type_name = NULL;
 735   char *cp = text + 1;
 736   symbol_list *effective_rule;
 737   int effective_rule_length;
 738   int n;
 739
 740   if (rule->midrule_parent_rule)
 741     {
 742       effective_rule = rule->midrule_parent_rule;
 743       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 744     }
 745   else
 746     {
 747       effective_rule = rule;
 748       effective_rule_length = symbol_list_length (rule->next);
 749     }
 750
 751   /* Get the type name if explicit. */
 752   cp = fetch_type_name (cp, &type_name, dollar_loc);
 753
 754   n = parse_ref (cp, effective_rule, effective_rule_length,
 755                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 756
 757   /* End type_name. */
 758   if (type_name)
 759     cp[-1] = '\0';
 760
 761   switch (n)
 762     {
 763     case INVALID_REF:
 764       break;
 765
 766     case LHS_REF:
 767       if (!type_name)
 768         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 769
 770       if (!type_name)
 771         {
 772           if (union_seen | tag_seen)
 773             {
 774               if (rule->midrule_parent_rule)
 775                 complain_at (dollar_loc,
 776                              _("$$ for the midrule at $%d of %s"
 777                                " has no declared type"),
 778                              rule->midrule_parent_rhs_index,
 779                              quote (effective_rule->content.sym->tag));
 780               else
 781                 complain_at (dollar_loc, _("$$ of %s has no declared type"),
 782                              quote (rule->content.sym->tag));
 783             }
 784           else
 785             untyped_var_seen = true;
 786         }
 787
 788       obstack_sgrow (&obstack_for_string, "]b4_lhs_value(");
 789       obstack_quote (&obstack_for_string, type_name);
 790       obstack_sgrow (&obstack_for_string, ")[");
 791       rule->action_props.is_value_used = true;
 792       break;
 793
 794     default:
 795       if (max_left_semantic_context < 1 - n)
 796         max_left_semantic_context = 1 - n;
 797       if (!type_name && 0 < n)
 798         type_name =
 799           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 800       if (!type_name)
 801         {
 802           if (union_seen | tag_seen)
 803             complain_at (dollar_loc, _("$%s of %s has no declared type"),
 804                          cp, quote (effective_rule->content.sym->tag));
 805           else
 806             untyped_var_seen = true;
 807         }
 808
 809       obstack_fgrow2 (&obstack_for_string,
 810                       "]b4_rhs_value(%d, %d, ", effective_rule_length, n);
 811       obstack_quote (&obstack_for_string, type_name);
 812       obstack_sgrow (&obstack_for_string, ")[");
 813       if (n > 0)
 814         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 815           true;
 816       break;
 817     }
 818 }
 819
 820
 821 /*------------------------------------------------------.
 822 | TEXT is a location token (i.e., a '@...').  Output to |
 823 | OBSTACK_FOR_STRING a reference to this location.      |
 824 `------------------------------------------------------*/
 825
 826 static void
 827 handle_action_at (symbol_list *rule, char *text, location at_loc)
 828 {
 829   char *cp = text + 1;
 830   symbol_list *effective_rule;
 831   int effective_rule_length;
 832   int n;
 833
 834   if (rule->midrule_parent_rule)
 835     {
 836       effective_rule = rule->midrule_parent_rule;
 837       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 838     }
 839   else
 840     {
 841       effective_rule = rule;
 842       effective_rule_length = symbol_list_length (rule->next);
 843     }
 844
 845   locations_flag = true;
 846
 847   n = parse_ref (cp, effective_rule, effective_rule_length,
 848                  rule->midrule_parent_rhs_index, text, at_loc, '@');
 849   switch (n)
 850     {
 851     case INVALID_REF:
 852       break;
 853
 854     case LHS_REF:
 855       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 856       break;
 857
 858     default:
 859       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 860                       effective_rule_length, n);
 861       break;
 862     }
 863 }
 864
 865
 866 /*-------------------------.
 867 | Initialize the scanner.  |
 868 `-------------------------*/
 869
 870 /* Translate the dollars and ats in \a self, in the context \a sc_context
 871    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 872
 873 static char const *
 874 translate_action (code_props *self, int sc_context)
 875 {
 876   char *res;
 877   static bool initialized = false;
 878   if (!initialized)
 879     {
 880       obstack_init (&obstack_for_string);
 881       yy_flex_debug = 0;
 882       initialized = true;
 883     }
 884
 885   loc->start = loc->end = self->location.start;
 886   yy_switch_to_buffer (yy_scan_string (self->code));
 887   res = code_lex (self, sc_context);
 888   yy_delete_buffer (YY_CURRENT_BUFFER);
 889
 890   return res;
 891 }
 892
 893 /*------------------------------------------------------------------------.
 894 | Implementation of the public interface as documented in "scan-code.h".  |
 895 `------------------------------------------------------------------------*/
 896
 897 void
 898 code_props_none_init (code_props *self)
 899 {
 900   *self = code_props_none;
 901 }
 902
 903 code_props const code_props_none = CODE_PROPS_NONE_INIT;
 904
 905 void
 906 code_props_plain_init (code_props *self, char const *code,
 907                        location code_loc)
 908 {
 909   self->kind = CODE_PROPS_PLAIN;
 910   self->code = code;
 911   self->location = code_loc;
 912   self->is_value_used = false;
 913   self->rule = NULL;
 914   self->named_ref = NULL;
 915 }
 916
 917 void
 918 code_props_symbol_action_init (code_props *self, char const *code,
 919                                location code_loc)
 920 {
 921   self->kind = CODE_PROPS_SYMBOL_ACTION;
 922   self->code = code;
 923   self->location = code_loc;
 924   self->is_value_used = false;
 925   self->rule = NULL;
 926   self->named_ref = NULL;
 927 }
 928
 929 void
 930 code_props_rule_action_init (code_props *self, char const *code,
 931                              location code_loc, symbol_list *rule,
 932                              named_ref *name)
 933 {
 934   self->kind = CODE_PROPS_RULE_ACTION;
 935   self->code = code;
 936   self->location = code_loc;
 937   self->is_value_used = false;
 938   self->rule = rule;
 939   self->named_ref = name;
 940 }
 941
 942 void
 943 code_props_translate_code (code_props *self)
 944 {
 945   switch (self->kind)
 946     {
 947       case CODE_PROPS_NONE:
 948         break;
 949       case CODE_PROPS_PLAIN:
 950         self->code = translate_action (self, INITIAL);
 951         break;
 952       case CODE_PROPS_SYMBOL_ACTION:
 953         self->code = translate_action (self, SC_SYMBOL_ACTION);
 954         break;
 955       case CODE_PROPS_RULE_ACTION:
 956         self->code = translate_action (self, SC_RULE_ACTION);
 957         break;
 958     }
 959 }
 960
 961 void
 962 code_scanner_last_string_free (void)
 963 {
 964   STRING_FREE;
 965 }
 966
 967 void
 968 code_scanner_free (void)
 969 {
 970   obstack_free (&obstack_for_string, 0);
 971   variant_table_free ();
 972
 973   /* Reclaim Flex's buffers.  */
 974   yylex_destroy ();
 975 }