src/scan-code.l

   1 /* Bison Action Scanner                             -*- C -*-
   2
   3    Copyright (C) 2006, 2007, 2008 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 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 void handle_action_dollar (symbol_list *rule, char *cp,
  50                                   location dollar_loc);
  51 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
  52
  53 /* A string to be pushed to obstack after dollar/at has been handled. */
  54 static char *ref_tail_fields;
  55
  56 static location the_location;
  57 static location *loc = &the_location;
  58
  59 /* A string representing the most recent translation.  */
  60 static char *last_string;
  61
  62 /* True if an untyped $$ or $n was seen.  */
  63 static bool untyped_var_seen;
  64
  65 %}
  66  /* C and C++ comments in code. */
  67 %x SC_COMMENT SC_LINE_COMMENT
  68  /* Strings and characters in code. */
  69 %x SC_STRING SC_CHARACTER
  70  /* Whether in a rule or symbol action.  Specifies the translation
  71     of $ and @.  */
  72 %x SC_RULE_ACTION SC_SYMBOL_ACTION
  73
  74
  75 /* POSIX says that a tag must be both an id and a C union member, but
  76    historically almost any character is allowed in a tag.  We disallow
  77    NUL and newline, as this simplifies our implementation.  */
  78 tag      [^\0\n>]+
  79
  80 /* Zero or more instances of backslash-newline.  Following GCC, allow
  81    white space between the backslash and the newline.  */
  82 splice   (\\[ \f\t\v]*\n)*
  83
  84 /* C style identifier. Must start with letter. Will be used for
  85    named symbol references. Shall be kept synchronized with
  86    scan-gram.l "letter" and "id". */
  87 letter    [-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
  88 id        {letter}({letter}|[0-9])*
  89 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
  90
  91 %%
  92
  93 %{
  94   /* Nesting level of the current code in braces.  */
  95   int braces_level = 0;
  96
  97   /* Whether a semicolon is probably needed.
  98      The heuristic is that a semicolon is not needed after `{', `}', `;',
  99      or a C preprocessor directive, and that whitespaces and comments
 100      do not affect this flag.
 101      Note that `{' does not need a semicolon because of `{}'.
 102      A semicolon may be needed before a cpp direcive, but don't bother.  */
 103   bool need_semicolon = false;
 104
 105   /* Whether in a C preprocessor directive.  Don't use a start condition
 106      for this because, at the end of strings and comments, we still need
 107      to know whether we're in a directive.  */
 108   bool in_cpp = false;
 109
 110   /* This scanner is special: it is invoked only once, henceforth
 111      is expected to return only once.  This initialization is
 112      therefore done once per action to translate. */
 113   aver (sc_context == SC_SYMBOL_ACTION
 114         || sc_context == SC_RULE_ACTION
 115         || sc_context == INITIAL);
 116   BEGIN sc_context;
 117 %}
 118
 119   /*------------------------------------------------------------.
 120   | Scanning a C comment.  The initial `/ *' is already eaten.  |
 121   `------------------------------------------------------------*/
 122
 123 <SC_COMMENT>
 124 {
 125   "*"{splice}"/"  STRING_GROW; BEGIN sc_context;
 126 }
 127
 128
 129   /*--------------------------------------------------------------.
 130   | Scanning a line comment.  The initial `//' is already eaten.  |
 131   `--------------------------------------------------------------*/
 132
 133 <SC_LINE_COMMENT>
 134 {
 135   "\n"           STRING_GROW; BEGIN sc_context;
 136   {splice}       STRING_GROW;
 137 }
 138
 139
 140   /*--------------------------------------------.
 141   | Scanning user-code characters and strings.  |
 142   `--------------------------------------------*/
 143
 144 <SC_CHARACTER,SC_STRING>
 145 {
 146   {splice}|\\{splice}.  STRING_GROW;
 147 }
 148
 149 <SC_CHARACTER>
 150 {
 151   "'"           STRING_GROW; BEGIN sc_context;
 152 }
 153
 154 <SC_STRING>
 155 {
 156   "\""          STRING_GROW; BEGIN sc_context;
 157 }
 158
 159
 160 <SC_RULE_ACTION,SC_SYMBOL_ACTION>{
 161   "'" {
 162     STRING_GROW;
 163     BEGIN SC_CHARACTER;
 164     need_semicolon = true;
 165   }
 166   "\"" {
 167     STRING_GROW;
 168     BEGIN SC_STRING;
 169     need_semicolon = true;
 170   }
 171   "/"{splice}"*" {
 172     STRING_GROW;
 173     BEGIN SC_COMMENT;
 174   }
 175   "/"{splice}"/" {
 176     STRING_GROW;
 177     BEGIN SC_LINE_COMMENT;
 178   }
 179 }
 180
 181 <SC_RULE_ACTION>
 182 {
 183   "$"("<"{tag}">")?{ref}  {
 184     ref_tail_fields = 0;
 185     handle_action_dollar (self->rule, yytext, *loc);
 186     if (ref_tail_fields) {
 187       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 188     }
 189     need_semicolon = true;
 190   }
 191   "@"{ref} {
 192     ref_tail_fields = 0;
 193     handle_action_at (self->rule, yytext, *loc);
 194     if (ref_tail_fields) {
 195       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 196     }
 197     need_semicolon = true;
 198   }
 199   "$"  {
 200     warn_at (*loc, _("stray `$'"));
 201     obstack_sgrow (&obstack_for_string, "$][");
 202     need_semicolon = true;
 203   }
 204   "@"  {
 205     warn_at (*loc, _("stray `@'"));
 206     obstack_sgrow (&obstack_for_string, "@@");
 207     need_semicolon = true;
 208   }
 209   "["  {
 210     obstack_sgrow (&obstack_for_string, "@{");
 211     need_semicolon = true;
 212   }
 213   "]"  {
 214     obstack_sgrow (&obstack_for_string, "@}");
 215     need_semicolon = true;
 216   }
 217
 218   ";"  STRING_GROW;                 need_semicolon = false;
 219   "{"  STRING_GROW; ++braces_level; need_semicolon = false;
 220   "}"  {
 221     bool outer_brace = --braces_level == 0;
 222
 223     /* As an undocumented Bison extension, append `;' before the last
 224        brace in braced code, so that the user code can omit trailing
 225        `;'.  But do not append `;' if emulating Yacc, since Yacc does
 226        not append one.  */
 227     if (outer_brace && !yacc_flag && language_prio == default_prio
 228         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
 229       {
 230         warn_at (*loc, _("a `;' might be needed at the end of action code"));
 231         warn_at (*loc, _("future versions of Bison will not add the `;'"));
 232         obstack_1grow (&obstack_for_string, ';');
 233       }
 234
 235     STRING_GROW;
 236     need_semicolon = false;
 237   }
 238
 239   /* Preprocessing directives should only be recognized at the beginning
 240      of lines, allowing whitespace including comments, but in C/C++,
 241      `#' can only be the start of preprocessor directives or within
 242      `#define' directives anyway, so don't bother with begin of line.  */
 243   "#"       STRING_GROW; in_cpp = true;
 244
 245   {splice}  STRING_GROW;
 246   [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;
 247   [ \t\f]   STRING_GROW;
 248   .         STRING_GROW; need_semicolon = true;
 249 }
 250
 251 <SC_SYMBOL_ACTION>
 252 {
 253   "$$" {
 254     obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar[");
 255     self->is_value_used = true;
 256   }
 257   "@$" {
 258     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
 259     locations_flag = true;
 260   }
 261 }
 262
 263
 264   /*-----------------------------------------.
 265   | Escape M4 quoting characters in C code.  |
 266   `-----------------------------------------*/
 267
 268 <*>
 269 {
 270   \$    obstack_sgrow (&obstack_for_string, "$][");
 271   \@    obstack_sgrow (&obstack_for_string, "@@");
 272   \[    obstack_sgrow (&obstack_for_string, "@{");
 273   \]    obstack_sgrow (&obstack_for_string, "@}");
 274 }
 275
 276   /*-----------------------------------------------------.
 277   | By default, grow the string obstack with the input.  |
 278   `-----------------------------------------------------*/
 279
 280 <*>.|\n STRING_GROW;
 281
 282  /* End of processing. */
 283 <*><<EOF>>       {
 284                    STRING_FINISH;
 285                    return last_string;
 286                  }
 287
 288 %%
 289
 290 static inline bool
 291 is_dot_or_dash (char ch)
 292 {
 293   return ch == '.' || ch == '-';
 294 }
 295
 296 static inline bool
 297 contains_dot_or_dash (const char* p)
 298 {
 299   for (; *p; ++p)
 300     if (is_dot_or_dash (*p))
 301       return true;
 302   return false;
 303 }
 304
 305 /* Defines a variant of a symbolic name resolution. */
 306 typedef struct
 307 {
 308   /* Index in symbol list. */
 309   unsigned index;
 310
 311   /* Matched symbol id and loc. */
 312   uniqstr id;
 313   location loc;
 314
 315   /* Hiding named reference. */
 316   named_ref* hidden_by;
 317
 318   /* Error flags. May contain zero (no errors) or
 319      a combination of VARIANT_* values. */
 320   unsigned err;
 321 } variant;
 322
 323 /* Set when the variant refers to a symbol hidden
 324    by an explicit symbol reference. */
 325 #define VARIANT_HIDDEN (1 << 0)
 326
 327 /* Set when the variant refers to a symbol containing
 328    dots or dashes. Will require explicit bracketing. */
 329 #define VARIANT_BAD_BRACKETING (1 << 1)
 330
 331 /* Set when the variant refers to a symbol which is
 332    not visible from current midrule. */
 333 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 334
 335 static variant *variant_table = 0;
 336 static unsigned variant_table_size = 0;
 337 static unsigned variant_count = 0;
 338
 339 static variant *
 340 variant_table_grow (void)
 341 {
 342   ++variant_count;
 343   if (variant_count > variant_table_size)
 344     {
 345       while (variant_count > variant_table_size)
 346         variant_table_size = 2 * variant_table_size + 3;
 347       variant_table = xnrealloc (variant_table, variant_table_size,
 348                                  sizeof *variant_table);
 349     }
 350   return &variant_table[variant_count - 1];
 351 }
 352
 353 static void
 354 variant_table_free (void)
 355 {
 356   free (variant_table);
 357   variant_table = 0;
 358   variant_table_size = variant_count = 0;
 359 }
 360
 361 static char *
 362 find_prefix_end (const char *prefix, char *begin, char *end)
 363 {
 364   char *ptr = begin;
 365
 366   for (; *prefix && ptr != end; ++prefix, ++ptr)
 367     if (*prefix != *ptr)
 368       return 0;
 369
 370   if (*prefix)
 371     return 0;
 372
 373   return ptr;
 374 }
 375
 376 static variant *
 377 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 378              char *cp, char *cp_end, bool exact_mode)
 379 {
 380   char *prefix_end;
 381
 382   prefix_end = find_prefix_end (id, cp, cp_end);
 383   if (prefix_end &&
 384       (prefix_end == cp_end ||
 385        (!exact_mode && is_dot_or_dash (*prefix_end))))
 386     {
 387       variant *r = variant_table_grow ();
 388       r->index = symbol_index;
 389       r->id = id;
 390       r->loc = id_loc;
 391       r->hidden_by = NULL;
 392       r->err = 0;
 393       return r;
 394     }
 395   else
 396     return NULL;
 397 }
 398
 399 static const char *
 400 get_at_spec(unsigned symbol_index)
 401 {
 402   static char at_buf[20];
 403   if (symbol_index == 0)
 404     strcpy (at_buf, "$$");
 405   else
 406     snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
 407   return at_buf;
 408 }
 409
 410 /* Returned from "parse_ref" when the reference
 411    is inappropriate. */
 412 #define INVALID_REF (INT_MIN)
 413
 414 /* Returned from "parse_ref" when the reference
 415    points to LHS ($$) of the current rule. */
 416 #define LHS_REF (INT_MIN + 1)
 417
 418 /* Parse named or positional reference. In case of positional
 419    references, can return negative values for $-n "deep" stack
 420    accesses. */
 421 static long int
 422 parse_ref (char *cp, symbol_list *rule, int rule_length,
 423            int midrule_rhs_index, char *text, location text_loc,
 424            char dollar_or_at)
 425 {
 426   symbol_list *l;
 427   char *cp_end;
 428   bool exact_mode;
 429   bool has_error;
 430   bool has_valid;
 431   unsigned i;
 432
 433   if ('$' == *cp)
 434     return LHS_REF;
 435
 436   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 437     {
 438       long int num = strtol (cp, &cp, 10);
 439       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 440         return num;
 441       else
 442         {
 443           complain_at (text_loc, _("integer out of range: %s"),
 444                        quote (text));
 445           return INVALID_REF;
 446         }
 447     }
 448
 449   if ('[' == *cp)
 450     {
 451       /* Ignore the brackets. */
 452       char *p;
 453       for (p = ++cp; *p != ']'; ++p)
 454         continue;
 455       cp_end = p;
 456
 457       exact_mode = true;
 458     }
 459   else
 460     {
 461       /* Take all characters of the name. */
 462       char* p;
 463       for (p = cp; *p; ++p)
 464         if (is_dot_or_dash (*p))
 465           {
 466             ref_tail_fields = p;
 467             break;
 468           }
 469       for (p = cp; *p; ++p)
 470         continue;
 471       cp_end = p;
 472
 473       exact_mode = false;
 474     }
 475
 476   /* Add all relevant variants. */
 477   {
 478     unsigned symbol_index;
 479     variant_count = 0;
 480     for (symbol_index = 0, l = rule; !symbol_list_null (l);
 481          ++symbol_index, l = l->next)
 482       {
 483         variant *var;
 484         if (l->content_type != SYMLIST_SYMBOL)
 485           continue;
 486
 487         var = variant_add (l->content.sym->tag, l->sym_loc,
 488                            symbol_index, cp, cp_end, exact_mode);
 489         if (var && l->named_ref)
 490           var->hidden_by = l->named_ref;
 491
 492         if (l->named_ref)
 493           variant_add (l->named_ref->id, l->named_ref->loc,
 494                        symbol_index, cp, cp_end, exact_mode);
 495       }
 496   }
 497
 498   /* Check errors. */
 499   has_error = false;
 500   has_valid = false;
 501   for (i = 0; i < variant_count; ++i)
 502     {
 503       variant *var = &variant_table[i];
 504       unsigned symbol_index = var->index;
 505
 506       /* Check visibility from mid-rule actions. */
 507       if (midrule_rhs_index != 0
 508           && (symbol_index == 0 || midrule_rhs_index < symbol_index))
 509         {
 510           var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 511           has_error = true;
 512         }
 513
 514       /* Check correct bracketing. */
 515       if (!exact_mode && contains_dot_or_dash (var->id))
 516         {
 517           var->err |= VARIANT_BAD_BRACKETING;
 518           has_error = true;
 519         }
 520
 521       /* Check using of hidden symbols. */
 522       if (var->hidden_by)
 523         {
 524           var->err |= VARIANT_HIDDEN;
 525           has_error = true;
 526         }
 527
 528       if (!var->err)
 529         has_valid = true;
 530     }
 531
 532   if (variant_count == 1 && has_valid)
 533     {
 534       /* The only "good" case is here. */
 535       unsigned symbol_index = variant_table[0].index;
 536       if (symbol_index == midrule_rhs_index)
 537         return LHS_REF;
 538       else
 539         return symbol_index;
 540     }
 541
 542   /* Start complaining. */
 543
 544   if (variant_count == 0)
 545     complain_at (text_loc, _("invalid reference: %s, symbol not found"),
 546                  quote (text));
 547   else if (variant_count > 1 && !has_error)
 548     complain_at (text_loc, _("ambiguous reference: %s"),
 549                  quote (text));
 550   else if (variant_count > 1 && has_valid && has_error)
 551     complain_at (text_loc, _("misleading reference: %s"),
 552                  quote (text));
 553   else
 554     complain_at (text_loc, _("invalid reference: %s"),
 555                  quote (text));
 556
 557   for (i = 0; i < variant_count; ++i)
 558     {
 559       const variant *var = &variant_table[i];
 560       const char *at_spec = get_at_spec (var->index);
 561
 562       if (var->err == 0)
 563         complain_at (var->loc, _("  refers to: %c%s at %s"),
 564                      dollar_or_at, var->id, at_spec);
 565       else
 566         {
 567           static struct obstack msg_buf;
 568           const char *tail = exact_mode ? "" :
 569             cp + strlen (var->id);
 570           const char *id = var->hidden_by ? var->hidden_by->id :
 571             var->id;
 572           location id_loc = var->hidden_by ? var->hidden_by->loc :
 573             var->loc;
 574
 575           /* Create the explanation message. */
 576           obstack_init (&msg_buf);
 577
 578           obstack_fgrow1 (&msg_buf, "  possibly meant: %c", dollar_or_at);
 579           if (contains_dot_or_dash (id))
 580             obstack_fgrow1 (&msg_buf, "[%s]", id);
 581           else
 582             obstack_sgrow (&msg_buf, id);
 583           obstack_sgrow (&msg_buf, tail);
 584
 585           if (var->err & VARIANT_HIDDEN)
 586             {
 587               obstack_fgrow1 (&msg_buf, ", hiding %c", dollar_or_at);
 588               if (contains_dot_or_dash (var->id))
 589                 obstack_fgrow1 (&msg_buf, "[%s]", var->id);
 590               else
 591                 obstack_sgrow (&msg_buf, var->id);
 592               obstack_sgrow (&msg_buf, tail);
 593             }
 594
 595           obstack_fgrow1 (&msg_buf, " at %s", at_spec);
 596
 597           if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 598             obstack_fgrow1 (&msg_buf, ", cannot be accessed from "
 599                             "mid-rule action at $%d", midrule_rhs_index);
 600
 601           obstack_1grow (&msg_buf, '\0');
 602           complain_at (id_loc, _("%s"), (char *) obstack_finish (&msg_buf));
 603           obstack_free (&msg_buf, 0);
 604         }
 605     }
 606
 607   return INVALID_REF;
 608 }
 609
 610 /* Keeps track of the maximum number of semantic values to the left of
 611    a handle (those referenced by $0, $-1, etc.) are required by the
 612    semantic actions of this grammar. */
 613 int max_left_semantic_context = 0;
 614
 615
 616 /*------------------------------------------------------------------.
 617 | TEXT is pointing to a wannabee semantic value (i.e., a `$').      |
 618 |                                                                   |
 619 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 620 |                                                                   |
 621 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 622 `------------------------------------------------------------------*/
 623
 624 static void
 625 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 626 {
 627   char const *type_name = NULL;
 628   char *cp = text + 1;
 629   char *gt_ptr = 0;
 630   symbol_list *effective_rule;
 631   int effective_rule_length;
 632   int n;
 633
 634   if (rule->midrule_parent_rule)
 635     {
 636       effective_rule = rule->midrule_parent_rule;
 637       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 638     }
 639   else
 640     {
 641       effective_rule = rule;
 642       effective_rule_length = symbol_list_length (rule->next);
 643     }
 644
 645   /* Get the type name if explicit. */
 646   if (*cp == '<')
 647     {
 648       type_name = ++cp;
 649       while (*cp != '>')
 650         ++cp;
 651
 652       /* The '>' symbol will be later replaced by '\0'. Original
 653          'text' is needed for error messages. */
 654       gt_ptr = cp;
 655       ++cp;
 656       if (untyped_var_seen)
 657         complain_at (dollar_loc, _("explicit type given in untyped grammar"));
 658       tag_seen = true;
 659     }
 660
 661   n = parse_ref (cp, effective_rule, effective_rule_length,
 662                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 663
 664   if (gt_ptr)
 665     *gt_ptr = '\0';
 666
 667   switch (n)
 668     {
 669     case INVALID_REF:
 670       break;
 671
 672     case LHS_REF:
 673       if (!type_name)
 674         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 675
 676       if (!type_name)
 677         {
 678           if (union_seen | tag_seen)
 679             {
 680               if (rule->midrule_parent_rule)
 681                 complain_at (dollar_loc,
 682                              _("$$ for the midrule at $%d of `%s'"
 683                                " has no declared type"),
 684                              rule->midrule_parent_rhs_index,
 685                              effective_rule->content.sym->tag);
 686               else
 687                 complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
 688                              rule->content.sym->tag);
 689             }
 690           else
 691             untyped_var_seen = true;
 692           type_name = "";
 693         }
 694
 695       obstack_fgrow1 (&obstack_for_string,
 696                       "]b4_lhs_value([%s])[", type_name);
 697       rule->action_props.is_value_used = true;
 698       break;
 699
 700     default:
 701       if (max_left_semantic_context < 1 - n)
 702         max_left_semantic_context = 1 - n;
 703       if (!type_name && 0 < n)
 704         type_name =
 705           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 706       if (!type_name)
 707         {
 708           if (union_seen | tag_seen)
 709             complain_at (dollar_loc, _("$%s of `%s' has no declared type"),
 710                          cp, effective_rule->content.sym->tag);
 711           else
 712             untyped_var_seen = true;
 713           type_name = "";
 714         }
 715
 716       obstack_fgrow3 (&obstack_for_string,
 717                       "]b4_rhs_value(%d, %d, [%s])[",
 718                       effective_rule_length, n, type_name);
 719       if (n > 0)
 720         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 721           true;
 722       break;
 723     }
 724 }
 725
 726
 727 /*------------------------------------------------------.
 728 | TEXT is a location token (i.e., a `@...').  Output to |
 729 | OBSTACK_FOR_STRING a reference to this location.      |
 730 `------------------------------------------------------*/
 731
 732 static void
 733 handle_action_at (symbol_list *rule, char *text, location at_loc)
 734 {
 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   locations_flag = true;
 752
 753   n = parse_ref (cp, effective_rule, effective_rule_length,
 754                        rule->midrule_parent_rhs_index, text, at_loc, '@');
 755   switch (n)
 756     {
 757     case INVALID_REF:
 758       break;
 759
 760     case LHS_REF:
 761       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 762       break;
 763
 764     default:
 765       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 766                       effective_rule_length, n);
 767       break;
 768     }
 769 }
 770
 771
 772 /*-------------------------.
 773 | Initialize the scanner.  |
 774 `-------------------------*/
 775
 776 /* Translate the dollars and ats in \a self, in the context \a sc_context
 777    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 778
 779 static char const *
 780 translate_action (code_props *self, int sc_context)
 781 {
 782   char *res;
 783   static bool initialized = false;
 784   if (!initialized)
 785     {
 786       obstack_init (&obstack_for_string);
 787       yy_flex_debug = 0;
 788       initialized = true;
 789     }
 790
 791   loc->start = loc->end = self->location.start;
 792   yy_switch_to_buffer (yy_scan_string (self->code));
 793   res = code_lex (self, sc_context);
 794   yy_delete_buffer (YY_CURRENT_BUFFER);
 795
 796   return res;
 797 }
 798
 799 /*------------------------------------------------------------------------.
 800 | Implementation of the public interface as documented in "scan-code.h".  |
 801 `------------------------------------------------------------------------*/
 802
 803 void
 804 code_props_none_init (code_props *self)
 805 {
 806   *self = code_props_none;
 807 }
 808
 809 code_props const code_props_none = CODE_PROPS_NONE_INIT;
 810
 811 void
 812 code_props_plain_init (code_props *self, char const *code,
 813                        location code_loc)
 814 {
 815   self->kind = CODE_PROPS_PLAIN;
 816   self->code = code;
 817   self->location = code_loc;
 818   self->is_value_used = false;
 819   self->rule = NULL;
 820   self->named_ref = NULL;
 821 }
 822
 823 void
 824 code_props_symbol_action_init (code_props *self, char const *code,
 825                                location code_loc)
 826 {
 827   self->kind = CODE_PROPS_SYMBOL_ACTION;
 828   self->code = code;
 829   self->location = code_loc;
 830   self->is_value_used = false;
 831   self->rule = NULL;
 832   self->named_ref = NULL;
 833 }
 834
 835 void
 836 code_props_rule_action_init (code_props *self, char const *code,
 837                              location code_loc, symbol_list *rule,
 838                              named_ref *name)
 839 {
 840   self->kind = CODE_PROPS_RULE_ACTION;
 841   self->code = code;
 842   self->location = code_loc;
 843   self->is_value_used = false;
 844   self->rule = rule;
 845   self->named_ref = name;
 846 }
 847
 848 void
 849 code_props_translate_code (code_props *self)
 850 {
 851   switch (self->kind)
 852     {
 853       case CODE_PROPS_NONE:
 854         break;
 855       case CODE_PROPS_PLAIN:
 856         self->code = translate_action (self, INITIAL);
 857         break;
 858       case CODE_PROPS_SYMBOL_ACTION:
 859         self->code = translate_action (self, SC_SYMBOL_ACTION);
 860         break;
 861       case CODE_PROPS_RULE_ACTION:
 862         self->code = translate_action (self, SC_RULE_ACTION);
 863         break;
 864     }
 865 }
 866
 867 void
 868 code_scanner_last_string_free (void)
 869 {
 870   STRING_FREE;
 871 }
 872
 873 void
 874 code_scanner_free (void)
 875 {
 876   obstack_free (&obstack_for_string, 0);
 877   variant_table_free ();
 878
 879   /* Reclaim Flex's buffers.  */
 880   yylex_destroy ();
 881 }