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 ()
 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 char *
 354 find_prefix_end (const char *prefix, char *begin, char *end)
 355 {
 356   char *ptr = begin;
 357
 358   for (; *prefix && ptr != end; ++prefix, ++ptr)
 359     if (*prefix != *ptr)
 360       return 0;
 361
 362   if (*prefix)
 363     return 0;
 364
 365   return ptr;
 366 }
 367
 368 static variant *
 369 variant_add (uniqstr id, location loc, unsigned index,
 370              char *cp, char *cp_end, bool exact_mode)
 371 {
 372   char *prefix_end;
 373
 374   prefix_end = find_prefix_end (id, cp, cp_end);
 375   if (prefix_end &&
 376       (prefix_end == cp_end ||
 377        (!exact_mode && is_dot_or_dash (*prefix_end))))
 378     {
 379       variant *r = variant_table_grow ();
 380       r->index = index;
 381       r->id = id;
 382       r->loc = loc;
 383       r->hidden_by = NULL;
 384       r->err = 0;
 385       return r;
 386     }
 387   else
 388     return NULL;
 389 }
 390
 391 static const char *
 392 get_at_spec(unsigned index)
 393 {
 394   static char at_buf[20];
 395   if (index == 0)
 396     strcpy (at_buf, "$$");
 397   else
 398     snprintf (at_buf, sizeof at_buf, "$%u", index);
 399   return at_buf;
 400 }
 401
 402 /* Returned from "parse_ref" when the reference
 403    is inappropriate. */
 404 #define INVALID_REF (INT_MIN)
 405
 406 /* Returned from "parse_ref" when the reference
 407    points to LHS ($$) of the current rule. */
 408 #define LHS_REF (INT_MIN + 1)
 409
 410 /* Parse named or positional reference. In case of positional
 411    references, can return negative values for $-n "deep" stack
 412    accesses. */
 413 static long int
 414 parse_ref (char *cp, symbol_list *rule, int rule_length,
 415            int midrule_rhs_index, char *text, location loc,
 416            char dollar_or_at)
 417 {
 418   symbol_list *l;
 419   char *cp_end;
 420   bool exact_mode;
 421   bool has_error;
 422   bool has_valid;
 423   unsigned i;
 424
 425   if ('$' == *cp)
 426     return LHS_REF;
 427
 428   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 429     {
 430       long int num = strtol (cp, &cp, 10);
 431       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 432         return num;
 433       else
 434         {
 435           complain_at (loc, _("integer out of range: %s"), quote (text));
 436           return INVALID_REF;
 437         }
 438     }
 439
 440   if ('[' == *cp)
 441     {
 442       /* Ignore the brackets. */
 443       char *p;
 444       for (p = ++cp; *p != ']'; ++p)
 445         continue;
 446       cp_end = p;
 447
 448       exact_mode = true;
 449     }
 450   else
 451     {
 452       /* Take all characters of the name. */
 453       char* p;
 454       for (p = cp; *p; ++p)
 455         if (is_dot_or_dash (*p))
 456           {
 457             ref_tail_fields = p;
 458             break;
 459           }
 460       for (p = cp; *p; ++p)
 461         continue;
 462       cp_end = p;
 463
 464       exact_mode = false;
 465     }
 466
 467   /* Add all relevant variants. */
 468   {
 469     unsigned index;
 470     variant_count = 0;
 471     for (index = 0, l = rule; !symbol_list_null (l); ++index, l = l->next)
 472       {
 473         variant *variant;
 474         if (l->content_type != SYMLIST_SYMBOL)
 475           continue;
 476
 477         variant = variant_add (l->content.sym->tag, l->sym_loc, index,
 478                                cp, cp_end, exact_mode);
 479
 480         if (variant && l->named_ref)
 481           variant->hidden_by = l->named_ref;
 482
 483         if (l->named_ref)
 484           variant_add (l->named_ref->id, l->named_ref->loc, index,
 485                        cp, cp_end, exact_mode);
 486       }
 487   }
 488
 489   /* Check errors. */
 490   has_error = false;
 491   has_valid = false;
 492   for (i = 0; i < variant_count; ++i)
 493     {
 494       variant *variant = &variant_table[i];
 495       unsigned index = variant->index;
 496
 497       /* Check visibility from mid-rule actions. */
 498       if (midrule_rhs_index != 0
 499           && (index == 0 || midrule_rhs_index < index))
 500         {
 501           variant->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 502           has_error = true;
 503         }
 504
 505       /* Check correct bracketing. */
 506       if (!exact_mode && contains_dot_or_dash (variant->id))
 507         {
 508           variant->err |= VARIANT_BAD_BRACKETING;
 509           has_error = true;
 510         }
 511
 512       /* Check using of hidden symbols. */
 513       if (variant->hidden_by)
 514         {
 515           variant->err |= VARIANT_HIDDEN;
 516           has_error = true;
 517         }
 518
 519       if (!variant->err)
 520         has_valid = true;
 521     }
 522
 523   if (variant_count == 1 && has_valid)
 524     {
 525       /* The only "good" case is here. */
 526       unsigned index = variant_table[0].index;
 527       if (index == midrule_rhs_index)
 528         return LHS_REF;
 529       else
 530         return index;
 531     }
 532
 533   /* Start complaining. */
 534
 535   if (variant_count == 0)
 536     complain_at (loc, _("invalid reference: %s, symbol not found"),
 537                  quote (text));
 538   else if (variant_count > 1 && !has_error)
 539     complain_at (loc, _("ambiguous reference: %s"),
 540                  quote (text));
 541   else if (variant_count > 1 && has_valid && has_error)
 542     complain_at (loc, _("misleading reference: %s"),
 543                  quote (text));
 544   else
 545     complain_at (loc, _("invalid reference: %s"),
 546                  quote (text));
 547
 548   for (i = 0; i < variant_count; ++i)
 549     {
 550       const variant *variant = &variant_table[i];
 551       const char *at_spec = get_at_spec (variant->index);
 552
 553       if (variant->err == 0)
 554         complain_at (variant->loc, _("  refers to: %c%s at %s"),
 555                      dollar_or_at, variant->id, at_spec);
 556       else
 557         {
 558           static struct obstack msg_buf;
 559           const char *tail = exact_mode ? "" :
 560             cp + strlen (variant->id);
 561           const char *id = variant->hidden_by ? variant->hidden_by->id :
 562             variant->id;
 563           location loc = variant->hidden_by ? variant->hidden_by->loc :
 564             variant->loc;
 565
 566           /* Create the explanation message. */
 567           obstack_init (&msg_buf);
 568
 569           obstack_fgrow1 (&msg_buf, "  possibly meant: %c", dollar_or_at);
 570           if (contains_dot_or_dash (id))
 571             obstack_fgrow1 (&msg_buf, "[%s]", id);
 572           else
 573             obstack_sgrow (&msg_buf, id);
 574           obstack_sgrow (&msg_buf, tail);
 575
 576           if (variant->err & VARIANT_HIDDEN)
 577             {
 578               obstack_fgrow1 (&msg_buf, ", hiding %c", dollar_or_at);
 579               if (contains_dot_or_dash (variant->id))
 580                 obstack_fgrow1 (&msg_buf, "[%s]", variant->id);
 581               else
 582                 obstack_sgrow (&msg_buf, variant->id);
 583               obstack_sgrow (&msg_buf, tail);
 584             }
 585
 586           obstack_fgrow1 (&msg_buf, " at %s", at_spec);
 587
 588           if (variant->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 589             obstack_fgrow1 (&msg_buf, ", cannot be accessed from "
 590                             "mid-rule action at $%d", midrule_rhs_index);
 591
 592           obstack_1grow (&msg_buf, '\0');
 593           complain_at (loc, _("%s"), (char *) obstack_finish (&msg_buf));
 594           obstack_free (&msg_buf, 0);
 595         }
 596     }
 597
 598   return INVALID_REF;
 599 }
 600
 601 /* Keeps track of the maximum number of semantic values to the left of
 602    a handle (those referenced by $0, $-1, etc.) are required by the
 603    semantic actions of this grammar. */
 604 int max_left_semantic_context = 0;
 605
 606
 607 /*------------------------------------------------------------------.
 608 | TEXT is pointing to a wannabee semantic value (i.e., a `$').      |
 609 |                                                                   |
 610 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 611 |                                                                   |
 612 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 613 `------------------------------------------------------------------*/
 614
 615 static void
 616 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 617 {
 618   char const *type_name = NULL;
 619   char *cp = text + 1;
 620   char *gt_ptr = 0;
 621   symbol_list *effective_rule;
 622   int effective_rule_length;
 623   int n;
 624
 625   if (rule->midrule_parent_rule)
 626     {
 627       effective_rule = rule->midrule_parent_rule;
 628       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 629     }
 630   else
 631     {
 632       effective_rule = rule;
 633       effective_rule_length = symbol_list_length (rule->next);
 634     }
 635
 636   /* Get the type name if explicit. */
 637   if (*cp == '<')
 638     {
 639       type_name = ++cp;
 640       while (*cp != '>')
 641         ++cp;
 642
 643       /* The '>' symbol will be later replaced by '\0'. Original
 644          'text' is needed for error messages. */
 645       gt_ptr = cp;
 646       ++cp;
 647       if (untyped_var_seen)
 648         complain_at (dollar_loc, _("explicit type given in untyped grammar"));
 649       tag_seen = true;
 650     }
 651
 652   n = parse_ref (cp, effective_rule, effective_rule_length,
 653                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 654
 655   if (gt_ptr)
 656     *gt_ptr = '\0';
 657
 658   switch (n)
 659     {
 660     case INVALID_REF:
 661       break;
 662
 663     case LHS_REF:
 664       if (!type_name)
 665         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 666
 667       if (!type_name)
 668         {
 669           if (union_seen | tag_seen)
 670             {
 671               if (rule->midrule_parent_rule)
 672                 complain_at (dollar_loc,
 673                              _("$$ for the midrule at $%d of `%s'"
 674                                " has no declared type"),
 675                              rule->midrule_parent_rhs_index,
 676                              effective_rule->content.sym->tag);
 677               else
 678                 complain_at (dollar_loc, _("$$ of `%s' has no declared type"),
 679                              rule->content.sym->tag);
 680             }
 681           else
 682             untyped_var_seen = true;
 683           type_name = "";
 684         }
 685
 686       obstack_fgrow1 (&obstack_for_string,
 687                       "]b4_lhs_value([%s])[", type_name);
 688       rule->action_props.is_value_used = true;
 689       break;
 690
 691     default:
 692       if (max_left_semantic_context < 1 - n)
 693         max_left_semantic_context = 1 - n;
 694       if (!type_name && 0 < n)
 695         type_name =
 696           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 697       if (!type_name)
 698         {
 699           if (union_seen | tag_seen)
 700             complain_at (dollar_loc, _("$%s of `%s' has no declared type"),
 701                          cp, effective_rule->content.sym->tag);
 702           else
 703             untyped_var_seen = true;
 704           type_name = "";
 705         }
 706
 707       obstack_fgrow3 (&obstack_for_string,
 708                       "]b4_rhs_value(%d, %d, [%s])[",
 709                       effective_rule_length, n, type_name);
 710       if (n > 0)
 711         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 712           true;
 713       break;
 714     }
 715 }
 716
 717
 718 /*------------------------------------------------------.
 719 | TEXT is a location token (i.e., a `@...').  Output to |
 720 | OBSTACK_FOR_STRING a reference to this location.      |
 721 `------------------------------------------------------*/
 722
 723 static void
 724 handle_action_at (symbol_list *rule, char *text, location at_loc)
 725 {
 726   char *cp = text + 1;
 727   symbol_list *effective_rule;
 728   int effective_rule_length;
 729   int n;
 730
 731   if (rule->midrule_parent_rule)
 732     {
 733       effective_rule = rule->midrule_parent_rule;
 734       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 735     }
 736   else
 737     {
 738       effective_rule = rule;
 739       effective_rule_length = symbol_list_length (rule->next);
 740     }
 741
 742   locations_flag = true;
 743
 744   n = parse_ref (cp, effective_rule, effective_rule_length,
 745                        rule->midrule_parent_rhs_index, text, at_loc, '@');
 746   switch (n)
 747     {
 748     case INVALID_REF:
 749       break;
 750
 751     case LHS_REF:
 752       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 753       break;
 754
 755     default:
 756       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 757                       effective_rule_length, n);
 758       break;
 759     }
 760 }
 761
 762
 763 /*-------------------------.
 764 | Initialize the scanner.  |
 765 `-------------------------*/
 766
 767 /* Translate the dollars and ats in \a self, in the context \a sc_context
 768    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 769
 770 static char const *
 771 translate_action (code_props *self, int sc_context)
 772 {
 773   char *res;
 774   static bool initialized = false;
 775   if (!initialized)
 776     {
 777       obstack_init (&obstack_for_string);
 778       yy_flex_debug = 0;
 779       initialized = true;
 780     }
 781
 782   loc->start = loc->end = self->location.start;
 783   yy_switch_to_buffer (yy_scan_string (self->code));
 784   res = code_lex (self, sc_context);
 785   yy_delete_buffer (YY_CURRENT_BUFFER);
 786
 787   return res;
 788 }
 789
 790 /*------------------------------------------------------------------------.
 791 | Implementation of the public interface as documented in "scan-code.h".  |
 792 `------------------------------------------------------------------------*/
 793
 794 void
 795 code_props_none_init (code_props *self)
 796 {
 797   *self = code_props_none;
 798 }
 799
 800 code_props const code_props_none = CODE_PROPS_NONE_INIT;
 801
 802 void
 803 code_props_plain_init (code_props *self, char const *code,
 804                        location code_loc)
 805 {
 806   self->kind = CODE_PROPS_PLAIN;
 807   self->code = code;
 808   self->location = code_loc;
 809   self->is_value_used = false;
 810   self->rule = NULL;
 811   self->named_ref = NULL;
 812 }
 813
 814 void
 815 code_props_symbol_action_init (code_props *self, char const *code,
 816                                location code_loc)
 817 {
 818   self->kind = CODE_PROPS_SYMBOL_ACTION;
 819   self->code = code;
 820   self->location = code_loc;
 821   self->is_value_used = false;
 822   self->rule = NULL;
 823   self->named_ref = NULL;
 824 }
 825
 826 void
 827 code_props_rule_action_init (code_props *self, char const *code,
 828                              location code_loc, symbol_list *rule,
 829                              named_ref *named_ref)
 830 {
 831   self->kind = CODE_PROPS_RULE_ACTION;
 832   self->code = code;
 833   self->location = code_loc;
 834   self->is_value_used = false;
 835   self->rule = rule;
 836   self->named_ref = named_ref;
 837 }
 838
 839 void
 840 code_props_translate_code (code_props *self)
 841 {
 842   switch (self->kind)
 843     {
 844       case CODE_PROPS_NONE:
 845         break;
 846       case CODE_PROPS_PLAIN:
 847         self->code = translate_action (self, INITIAL);
 848         break;
 849       case CODE_PROPS_SYMBOL_ACTION:
 850         self->code = translate_action (self, SC_SYMBOL_ACTION);
 851         break;
 852       case CODE_PROPS_RULE_ACTION:
 853         self->code = translate_action (self, SC_RULE_ACTION);
 854         break;
 855     }
 856 }
 857
 858 void
 859 code_scanner_last_string_free (void)
 860 {
 861   STRING_FREE;
 862 }
 863
 864 void
 865 code_scanner_free (void)
 866 {
 867   obstack_free (&obstack_for_string, 0);
 868   /* Reclaim Flex's buffers.  */
 869   yylex_destroy ();
 870 }