src/scan-code.l

   1 /* Bison Action Scanner                             -*- C -*-
   2
   3    Copyright (C) 2006-2013 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 <src/flex-scanner.h>
  31
  32 #include <src/complain.h>
  33 #include <src/reader.h>
  34 #include <src/getargs.h>
  35 #include <src/muscle-tab.h>
  36 #include <src/scan-code.h>
  37 #include <src/symlist.h>
  38
  39 #include <c-ctype.h>
  40 #include <get-errno.h>
  41 #include <quote.h>
  42
  43 /* The current calling start condition: SC_RULE_ACTION or
  44    SC_SYMBOL_ACTION. */
  45 # define YY_DECL static char *code_lex (code_props *self, int sc_context)
  46 YY_DECL;
  47
  48 #define YY_USER_ACTION  location_compute (loc, &loc->end, yytext, yyleng);
  49
  50 static char *fetch_type_name (char *cp, char const **type_name,
  51                               location dollar_loc);
  52
  53 static void handle_action_dollar (symbol_list *rule, char *cp,
  54                                   location dollar_loc);
  55 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
  56
  57 /* A string to be pushed to obstack after dollar/at has been handled. */
  58 static char *ref_tail_fields;
  59
  60 static location the_location;
  61 static location *loc = &the_location;
  62
  63 /* A string representing the most recent translation.  */
  64 static char *last_string;
  65
  66 /* True if an untyped $$ or $n was seen.  */
  67 static bool untyped_var_seen;
  68
  69 %}
  70  /* C and C++ comments in code. */
  71 %x SC_COMMENT SC_LINE_COMMENT
  72  /* Strings and characters in code. */
  73 %x SC_STRING SC_CHARACTER
  74  /* Whether in a rule or symbol action.  Specifies the translation
  75     of $ and @.  */
  76 %x SC_RULE_ACTION SC_SYMBOL_ACTION
  77
  78
  79 /* POSIX says that a tag must be both an id and a C union member, but
  80    historically almost any character is allowed in a tag.  We disallow
  81    NUL and newline, as this simplifies our implementation.  */
  82 tag      [^\0\n>]+
  83
  84 /* Zero or more instances of backslash-newline.  Following GCC, allow
  85    white space between the backslash and the newline.  */
  86 splice   (\\[ \f\t\v]*\n)*
  87
  88 /* C style identifier. Must start with letter. Will be used for
  89    named symbol references. Shall be kept synchronized with
  90    scan-gram.l "letter" and "id". */
  91 letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
  92 id        {letter}({letter}|[-0-9])*
  93 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
  94
  95 %%
  96
  97 %{
  98   /* This scanner is special: it is invoked only once, henceforth
  99      is expected to return only once.  This initialization is
 100      therefore done once per action to translate. */
 101   aver (sc_context == SC_SYMBOL_ACTION
 102         || sc_context == SC_RULE_ACTION
 103         || sc_context == INITIAL);
 104   BEGIN sc_context;
 105 %}
 106
 107   /*------------------------------------------------------------.
 108   | Scanning a C comment.  The initial '/ *' is already eaten.  |
 109   `------------------------------------------------------------*/
 110
 111 <SC_COMMENT>
 112 {
 113   "*"{splice}"/"  STRING_GROW; BEGIN sc_context;
 114 }
 115
 116
 117   /*--------------------------------------------------------------.
 118   | Scanning a line comment.  The initial '//' is already eaten.  |
 119   `--------------------------------------------------------------*/
 120
 121 <SC_LINE_COMMENT>
 122 {
 123   "\n"           STRING_GROW; BEGIN sc_context;
 124   {splice}       STRING_GROW;
 125 }
 126
 127
 128   /*--------------------------------------------.
 129   | Scanning user-code characters and strings.  |
 130   `--------------------------------------------*/
 131
 132 <SC_CHARACTER,SC_STRING>
 133 {
 134   {splice}|\\{splice}.  STRING_GROW;
 135 }
 136
 137 <SC_CHARACTER>
 138 {
 139   "'"           STRING_GROW; BEGIN sc_context;
 140 }
 141
 142 <SC_STRING>
 143 {
 144   "\""          STRING_GROW; BEGIN sc_context;
 145 }
 146
 147
 148 <SC_RULE_ACTION,SC_SYMBOL_ACTION>
 149 {
 150   "'"              STRING_GROW; BEGIN SC_CHARACTER;
 151   "\""             STRING_GROW; BEGIN SC_STRING;
 152   "/"{splice}"*"   STRING_GROW; BEGIN SC_COMMENT;
 153   "/"{splice}"/"   STRING_GROW; BEGIN SC_LINE_COMMENT;
 154
 155   [$@]  {
 156     complain (loc, Wother, _("stray '%s'"), yytext);
 157     obstack_escape (&obstack_for_string, yytext);
 158   }
 159 }
 160
 161 <SC_RULE_ACTION>
 162 {
 163   "$"("<"{tag}">")?{ref}  {
 164     ref_tail_fields = NULL;
 165     handle_action_dollar (self->rule, yytext, *loc);
 166     if (ref_tail_fields)
 167       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 168   }
 169   "@"{ref} {
 170     ref_tail_fields = NULL;
 171     handle_action_at (self->rule, yytext, *loc);
 172     if (ref_tail_fields)
 173       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 174   }
 175 }
 176
 177 <SC_SYMBOL_ACTION>
 178 {
 179   "$"("<"{tag}">")?"$" {
 180     const char *type_name = NULL;
 181     fetch_type_name (yytext + 1, &type_name, *loc)[-1] = 0;
 182     obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar(");
 183     obstack_quote (&obstack_for_string, type_name);
 184     obstack_sgrow (&obstack_for_string, ")[");
 185     self->is_value_used = true;
 186   }
 187   "@$" {
 188     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
 189     muscle_percent_define_ensure("locations", the_location, true);
 190   }
 191 }
 192
 193
 194 <*>
 195 {
 196   /* Escape M4 quoting characters in C code.  */
 197   [$@\[\]]    obstack_escape (&obstack_for_string, yytext);
 198
 199   /* By default, grow the string obstack with the input.  */
 200   .|\n        STRING_GROW;
 201
 202  /* End of processing. */
 203   <<EOF>>     STRING_FINISH; return last_string;
 204 }
 205
 206 %%
 207
 208 static inline bool
 209 is_dot_or_dash (char ch)
 210 {
 211   return ch == '.' || ch == '-';
 212 }
 213
 214 static inline bool
 215 contains_dot_or_dash (const char* p)
 216 {
 217   for (; *p; ++p)
 218     if (is_dot_or_dash (*p))
 219       return true;
 220   return false;
 221 }
 222
 223 /* Defines a variant of a symbolic name resolution. */
 224 typedef struct
 225 {
 226   /* Index in symbol list. */
 227   unsigned symbol_index;
 228
 229   /* Matched symbol id and loc. */
 230   uniqstr id;
 231   location loc;
 232
 233   /* Hiding named reference. */
 234   named_ref* hidden_by;
 235
 236   /* Error flags. May contain zero (no errors) or
 237      a combination of VARIANT_* values. */
 238   unsigned err;
 239 } variant;
 240
 241 /* Set when the variant refers to a symbol hidden
 242    by an explicit symbol reference. */
 243 #define VARIANT_HIDDEN (1 << 0)
 244
 245 /* Set when the variant refers to a symbol containing
 246    dots or dashes. Will require explicit bracketing. */
 247 #define VARIANT_BAD_BRACKETING (1 << 1)
 248
 249 /* Set when the variant refers to a symbol which is
 250    not visible from current midrule. */
 251 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 252
 253 static variant *variant_table = NULL;
 254 static unsigned variant_table_size = 0;
 255 static unsigned variant_count = 0;
 256
 257 static variant *
 258 variant_table_grow (void)
 259 {
 260   ++variant_count;
 261   if (variant_count > variant_table_size)
 262     {
 263       while (variant_count > variant_table_size)
 264         variant_table_size = 2 * variant_table_size + 3;
 265       variant_table = xnrealloc (variant_table, variant_table_size,
 266                                  sizeof *variant_table);
 267     }
 268   return &variant_table[variant_count - 1];
 269 }
 270
 271 static void
 272 variant_table_free (void)
 273 {
 274   free (variant_table);
 275   variant_table = NULL;
 276   variant_table_size = variant_count = 0;
 277 }
 278
 279 static char *
 280 find_prefix_end (const char *prefix, char *begin, char *end)
 281 {
 282   char *ptr = begin;
 283
 284   for (; *prefix && ptr != end; ++prefix, ++ptr)
 285     if (*prefix != *ptr)
 286       return 0;
 287
 288   if (*prefix)
 289     return 0;
 290
 291   return ptr;
 292 }
 293
 294 static variant *
 295 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 296              char *cp, char *cp_end, bool explicit_bracketing)
 297 {
 298   char *prefix_end;
 299
 300   prefix_end = find_prefix_end (id, cp, cp_end);
 301   if (prefix_end &&
 302       (prefix_end == cp_end ||
 303        (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
 304     {
 305       variant *r = variant_table_grow ();
 306       r->symbol_index = symbol_index;
 307       r->id = id;
 308       r->loc = id_loc;
 309       r->hidden_by = NULL;
 310       r->err = 0;
 311       return r;
 312     }
 313   else
 314     return NULL;
 315 }
 316
 317 static const char *
 318 get_at_spec(unsigned symbol_index)
 319 {
 320   static char at_buf[20];
 321   if (symbol_index == 0)
 322     strcpy (at_buf, "$$");
 323   else
 324     snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
 325   return at_buf;
 326 }
 327
 328 static void
 329 show_sub_message (warnings warning,
 330                   const char* cp, bool explicit_bracketing,
 331                   int midrule_rhs_index, char dollar_or_at,
 332                   unsigned indent, const variant *var)
 333 {
 334   const char *at_spec = get_at_spec (var->symbol_index);
 335
 336   if (var->err == 0)
 337     complain_indent (&var->loc, warning, &indent,
 338                      _("refers to: %c%s at %s"), dollar_or_at,
 339                      var->id, at_spec);
 340   else
 341     {
 342       static struct obstack msg_buf;
 343       const char *tail = explicit_bracketing ? "" : cp + strlen (var->id);
 344       const char *id = var->hidden_by ? var->hidden_by->id : var->id;
 345       location id_loc = var->hidden_by ? var->hidden_by->loc : var->loc;
 346
 347       /* Create the explanation message. */
 348       obstack_init (&msg_buf);
 349
 350       obstack_printf (&msg_buf, _("possibly meant: %c"), dollar_or_at);
 351       if (contains_dot_or_dash (id))
 352         obstack_printf (&msg_buf, "[%s]", id);
 353       else
 354         obstack_sgrow (&msg_buf, id);
 355       obstack_sgrow (&msg_buf, tail);
 356
 357       if (var->err & VARIANT_HIDDEN)
 358         {
 359           obstack_printf (&msg_buf, _(", hiding %c"), dollar_or_at);
 360           if (contains_dot_or_dash (var->id))
 361             obstack_printf (&msg_buf, "[%s]", var->id);
 362           else
 363             obstack_sgrow (&msg_buf, var->id);
 364           obstack_sgrow (&msg_buf, tail);
 365         }
 366
 367       obstack_printf (&msg_buf, _(" at %s"), at_spec);
 368
 369       if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 370         obstack_printf (&msg_buf,
 371                         _(", cannot be accessed from mid-rule action at $%d"),
 372                         midrule_rhs_index);
 373
 374       complain_indent (&id_loc, warning, &indent, "%s",
 375                         obstack_finish0 (&msg_buf));
 376       obstack_free (&msg_buf, 0);
 377     }
 378 }
 379
 380 static void
 381 show_sub_messages (warnings warning,
 382                    const char* cp, bool explicit_bracketing,
 383                    int midrule_rhs_index, char dollar_or_at,
 384                    unsigned indent)
 385 {
 386   unsigned i;
 387
 388   for (i = 0; i < variant_count; ++i)
 389     show_sub_message (warning | silent,
 390                       cp, explicit_bracketing,
 391                       midrule_rhs_index, dollar_or_at,
 392                       indent, &variant_table[i]);
 393 }
 394
 395 /* Returned from "parse_ref" when the reference
 396    is inappropriate. */
 397 #define INVALID_REF (INT_MIN)
 398
 399 /* Returned from "parse_ref" when the reference
 400    points to LHS ($$) of the current rule or midrule. */
 401 #define LHS_REF (INT_MIN + 1)
 402
 403 /* Parse named or positional reference. In case of positional
 404    references, can return negative values for $-n "deep" stack
 405    accesses. */
 406 static long int
 407 parse_ref (char *cp, symbol_list *rule, int rule_length,
 408            int midrule_rhs_index, char *text, location text_loc,
 409            char dollar_or_at)
 410 {
 411   symbol_list *l;
 412   char *cp_end;
 413   bool explicit_bracketing;
 414   unsigned i;
 415   unsigned valid_variants = 0;
 416   unsigned valid_variant_index = 0;
 417
 418   if ('$' == *cp)
 419     return LHS_REF;
 420
 421   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 422     {
 423       long int num = strtol (cp, &cp, 10);
 424       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 425         return num;
 426       else
 427         {
 428           complain (&text_loc, complaint, _("integer out of range: %s"),
 429                     quote (text));
 430           return INVALID_REF;
 431         }
 432     }
 433
 434   if ('[' == *cp)
 435     {
 436       /* Ignore the brackets. */
 437       char *p;
 438       for (p = ++cp; *p != ']'; ++p)
 439         continue;
 440       cp_end = p;
 441
 442       explicit_bracketing = true;
 443     }
 444   else
 445     {
 446       /* Take all characters of the name. */
 447       char* p;
 448       for (p = cp; *p; ++p)
 449         if (is_dot_or_dash (*p))
 450           {
 451             ref_tail_fields = p;
 452             break;
 453           }
 454       for (p = cp; *p; ++p)
 455         continue;
 456       cp_end = p;
 457
 458       explicit_bracketing = false;
 459     }
 460
 461   /* Add all relevant variants. */
 462   {
 463     unsigned symbol_index;
 464     variant_count = 0;
 465     for (symbol_index = 0, l = rule; !symbol_list_null (l);
 466          ++symbol_index, l = l->next)
 467       {
 468         variant *var;
 469         if (l->content_type != SYMLIST_SYMBOL)
 470           continue;
 471
 472         var = variant_add (l->content.sym->tag, l->sym_loc,
 473                            symbol_index, cp, cp_end, explicit_bracketing);
 474         if (var && l->named_ref)
 475           var->hidden_by = l->named_ref;
 476
 477         if (l->named_ref)
 478           variant_add (l->named_ref->id, l->named_ref->loc,
 479                        symbol_index, cp, cp_end, explicit_bracketing);
 480       }
 481   }
 482
 483   /* Check errors. */
 484   for (i = 0; i < variant_count; ++i)
 485     {
 486       variant *var = &variant_table[i];
 487       unsigned symbol_index = var->symbol_index;
 488
 489       /* Check visibility from mid-rule actions. */
 490       if (midrule_rhs_index != 0
 491           && (symbol_index == 0 || midrule_rhs_index < symbol_index))
 492         var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 493
 494       /* Check correct bracketing. */
 495       if (!explicit_bracketing && contains_dot_or_dash (var->id))
 496         var->err |= VARIANT_BAD_BRACKETING;
 497
 498       /* Check using of hidden symbols. */
 499       if (var->hidden_by)
 500         var->err |= VARIANT_HIDDEN;
 501
 502       if (!var->err)
 503         {
 504           valid_variant_index = i;
 505           ++valid_variants;
 506         }
 507     }
 508
 509   switch (valid_variants)
 510     {
 511     case 0:
 512       {
 513         unsigned len = (explicit_bracketing || !ref_tail_fields) ?
 514           cp_end - cp : ref_tail_fields - cp;
 515         unsigned indent = 0;
 516
 517         complain_indent (&text_loc, complaint, &indent,
 518                          _("invalid reference: %s"), quote (text));
 519         indent += SUB_INDENT;
 520         if (len == 0)
 521           {
 522             location sym_loc = text_loc;
 523             sym_loc.start.column += 1;
 524             sym_loc.end = sym_loc.start;
 525             complain_indent (&sym_loc, complaint, &indent,
 526                              _("syntax error after '%c', expecting integer, "
 527                                "letter, '_', '[', or '$'"),
 528                              dollar_or_at);
 529           }
 530         else if (midrule_rhs_index)
 531           complain_indent (&rule->location, complaint, &indent,
 532                            _("symbol not found in production before $%d: "
 533                              "%.*s"),
 534                            midrule_rhs_index, len, cp);
 535         else
 536           complain_indent (&rule->location, complaint, &indent,
 537                            _("symbol not found in production: %.*s"),
 538                            len, cp);
 539
 540         if (variant_count > 0)
 541           show_sub_messages (complaint,
 542                              cp, explicit_bracketing, midrule_rhs_index,
 543                              dollar_or_at, indent);
 544         return INVALID_REF;
 545       }
 546     case 1:
 547       {
 548         unsigned indent = 0;
 549         if (variant_count > 1)
 550           {
 551             complain_indent (&text_loc, Wother, &indent,
 552                              _("misleading reference: %s"), quote (text));
 553             show_sub_messages (Wother,
 554                                cp, explicit_bracketing, midrule_rhs_index,
 555                                dollar_or_at, indent + SUB_INDENT);
 556           }
 557         {
 558           unsigned symbol_index =
 559             variant_table[valid_variant_index].symbol_index;
 560           return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
 561         }
 562       }
 563     case 2:
 564     default:
 565       {
 566         unsigned indent = 0;
 567         complain_indent (&text_loc, complaint, &indent,
 568                          _("ambiguous reference: %s"), quote (text));
 569         show_sub_messages (complaint,
 570                            cp, explicit_bracketing, midrule_rhs_index,
 571                            dollar_or_at, indent + SUB_INDENT);
 572         return INVALID_REF;
 573       }
 574     }
 575
 576   /* Not reachable. */
 577   return INVALID_REF;
 578 }
 579
 580 /* Keeps track of the maximum number of semantic values to the left of
 581    a handle (those referenced by $0, $-1, etc.) are required by the
 582    semantic actions of this grammar. */
 583 int max_left_semantic_context = 0;
 584
 585
 586 /* If CP points to a typename (i.e., <.*?>), set TYPE_NAME to its
 587    beginning (i.e., after the opening "<", and return the pointer
 588    immediately after it.  */
 589
 590 static
 591 char *
 592 fetch_type_name (char *cp, char const **type_name,
 593                  location dollar_loc)
 594 {
 595   if (*cp == '<')
 596     {
 597       *type_name = ++cp;
 598       while (*cp != '>')
 599         ++cp;
 600
 601       /* The '>' symbol will be later replaced by '\0'. Original
 602          'text' is needed for error messages. */
 603       ++cp;
 604       if (untyped_var_seen)
 605         complain (&dollar_loc, complaint,
 606                   _("explicit type given in untyped grammar"));
 607       tag_seen = true;
 608     }
 609   return cp;
 610 }
 611
 612 /*------------------------------------------------------------------.
 613 | TEXT is pointing to a wannabee semantic value (i.e., a '$').      |
 614 |                                                                   |
 615 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 616 |                                                                   |
 617 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 618 `------------------------------------------------------------------*/
 619
 620 static void
 621 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 622 {
 623   char const *type_name = NULL;
 624   char *cp = text + 1;
 625   symbol_list *effective_rule;
 626   int effective_rule_length;
 627   int n;
 628
 629   if (rule->midrule_parent_rule)
 630     {
 631       effective_rule = rule->midrule_parent_rule;
 632       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 633     }
 634   else
 635     {
 636       effective_rule = rule;
 637       effective_rule_length = symbol_list_length (rule->next);
 638     }
 639
 640   /* Get the type name if explicit. */
 641   cp = fetch_type_name (cp, &type_name, dollar_loc);
 642
 643   n = parse_ref (cp, effective_rule, effective_rule_length,
 644                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 645
 646   /* End type_name. */
 647   if (type_name)
 648     cp[-1] = '\0';
 649
 650   switch (n)
 651     {
 652     case INVALID_REF:
 653       break;
 654
 655     case LHS_REF:
 656       if (!type_name)
 657         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 658
 659       if (!type_name)
 660         {
 661           if (union_seen | tag_seen)
 662             {
 663               if (rule->midrule_parent_rule)
 664                 complain (&dollar_loc, complaint,
 665                              _("$$ for the midrule at $%d of %s"
 666                                " has no declared type"),
 667                              rule->midrule_parent_rhs_index,
 668                              quote (effective_rule->content.sym->tag));
 669               else
 670                 complain (&dollar_loc, complaint,
 671                           _("$$ of %s has no declared type"),
 672                           quote (rule->content.sym->tag));
 673             }
 674           else
 675             untyped_var_seen = true;
 676         }
 677
 678       obstack_sgrow (&obstack_for_string, "]b4_lhs_value(");
 679       obstack_quote (&obstack_for_string, type_name);
 680       obstack_sgrow (&obstack_for_string, ")[");
 681       rule->action_props.is_value_used = true;
 682       break;
 683
 684     default:
 685       if (max_left_semantic_context < 1 - n)
 686         max_left_semantic_context = 1 - n;
 687       if (!type_name && 0 < n)
 688         type_name =
 689           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 690       if (!type_name)
 691         {
 692           if (union_seen | tag_seen)
 693             complain (&dollar_loc, complaint,
 694                       _("$%s of %s has no declared type"), cp,
 695                       quote (effective_rule->content.sym->tag));
 696           else
 697             untyped_var_seen = true;
 698         }
 699
 700       obstack_printf (&obstack_for_string,
 701                       "]b4_rhs_value(%d, %d, ", effective_rule_length, n);
 702       obstack_quote (&obstack_for_string, type_name);
 703       obstack_sgrow (&obstack_for_string, ")[");
 704       if (n > 0)
 705         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 706           true;
 707       break;
 708     }
 709 }
 710
 711
 712 /*------------------------------------------------------.
 713 | TEXT is a location token (i.e., a '@...').  Output to |
 714 | OBSTACK_FOR_STRING a reference to this location.      |
 715 `------------------------------------------------------*/
 716
 717 static void
 718 handle_action_at (symbol_list *rule, char *text, location at_loc)
 719 {
 720   char *cp = text + 1;
 721   symbol_list *effective_rule;
 722   int effective_rule_length;
 723   int n;
 724
 725   if (rule->midrule_parent_rule)
 726     {
 727       effective_rule = rule->midrule_parent_rule;
 728       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 729     }
 730   else
 731     {
 732       effective_rule = rule;
 733       effective_rule_length = symbol_list_length (rule->next);
 734     }
 735
 736   muscle_percent_define_ensure("locations", at_loc, true);
 737
 738   n = parse_ref (cp, effective_rule, effective_rule_length,
 739                        rule->midrule_parent_rhs_index, text, at_loc, '@');
 740   switch (n)
 741     {
 742     case INVALID_REF:
 743       break;
 744
 745     case LHS_REF:
 746       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 747       break;
 748
 749     default:
 750       obstack_printf (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 751                       effective_rule_length, n);
 752       break;
 753     }
 754 }
 755
 756
 757 /*-------------------------.
 758 | Initialize the scanner.  |
 759 `-------------------------*/
 760
 761 /* Translate the dollars and ats in \a self, in the context \a sc_context
 762    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 763
 764 static char const *
 765 translate_action (code_props *self, int sc_context)
 766 {
 767   char *res;
 768   static bool initialized = false;
 769   if (!initialized)
 770     {
 771       obstack_init (&obstack_for_string);
 772       yy_flex_debug = 0;
 773       initialized = true;
 774     }
 775
 776   loc->start = loc->end = self->location.start;
 777   yy_switch_to_buffer (yy_scan_string (self->code));
 778   res = code_lex (self, sc_context);
 779   yy_delete_buffer (YY_CURRENT_BUFFER);
 780
 781   return res;
 782 }
 783
 784 /*------------------------------------------------------------------------.
 785 | Implementation of the public interface as documented in "scan-code.h".  |
 786 `------------------------------------------------------------------------*/
 787
 788 void
 789 code_props_none_init (code_props *self)
 790 {
 791   *self = code_props_none;
 792 }
 793
 794 code_props code_props_none = CODE_PROPS_NONE_INIT;
 795
 796 void
 797 code_props_plain_init (code_props *self, char const *code,
 798                        location code_loc)
 799 {
 800   code_props_none_init (self);
 801   self->kind = CODE_PROPS_PLAIN;
 802   self->code = code;
 803   self->location = code_loc;
 804 }
 805
 806 void
 807 code_props_symbol_action_init (code_props *self, char const *code,
 808                                location code_loc)
 809 {
 810   code_props_none_init (self);
 811   self->kind = CODE_PROPS_SYMBOL_ACTION;
 812   self->code = code;
 813   self->location = code_loc;
 814 }
 815
 816 void
 817 code_props_rule_action_init (code_props *self, char const *code,
 818                              location code_loc, symbol_list *rule,
 819                              named_ref *name, bool is_predicate)
 820 {
 821   code_props_none_init (self);
 822   self->kind = CODE_PROPS_RULE_ACTION;
 823   self->code = code;
 824   self->location = code_loc;
 825   self->rule = rule;
 826   self->named_ref = name;
 827   self->is_predicate = is_predicate;
 828 }
 829
 830 void
 831 code_props_translate_code (code_props *self)
 832 {
 833   switch (self->kind)
 834     {
 835       case CODE_PROPS_NONE:
 836         break;
 837       case CODE_PROPS_PLAIN:
 838         self->code = translate_action (self, INITIAL);
 839         break;
 840       case CODE_PROPS_SYMBOL_ACTION:
 841         self->code = translate_action (self, SC_SYMBOL_ACTION);
 842         break;
 843       case CODE_PROPS_RULE_ACTION:
 844         self->code = translate_action (self, SC_RULE_ACTION);
 845         break;
 846     }
 847 }
 848
 849 void
 850 code_scanner_last_string_free (void)
 851 {
 852   STRING_FREE;
 853 }
 854
 855 void
 856 code_scanner_free (void)
 857 {
 858   obstack_free (&obstack_for_string, 0);
 859   variant_table_free ();
 860
 861   /* Reclaim Flex's buffers.  */
 862   yylex_destroy ();
 863 }