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