src/scan-code.l

   1 /* Bison Action Scanner                             -*- C -*-
   2
   3    Copyright (C) 2006-2012 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 %option debug nodefault noinput nounput noyywrap never-interactive
  21 %option prefix="code_" outfile="lex.yy.c"
  22
  23 %{
  24 /* Work around a bug in flex 2.5.31.  See Debian bug 333231
  25    <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>.  */
  26 #undef code_wrap
  27 #define code_wrap() 1
  28
  29 #define FLEX_PREFIX(Id) code_ ## Id
  30 #include "flex-scanner.h"
  31
  32 #include "complain.h"
  33 #include "reader.h"
  34 #include "getargs.h"
  35 #include "scan-code.h"
  36 #include "symlist.h"
  37
  38 #include <c-ctype.h>
  39 #include <get-errno.h>
  40 #include <quote.h>
  41
  42 /* The current calling start condition: SC_RULE_ACTION or
  43    SC_SYMBOL_ACTION. */
  44 # define YY_DECL static char *code_lex (code_props *self, int sc_context)
  45 YY_DECL;
  46
  47 #define YY_USER_ACTION  location_compute (loc, &loc->end, yytext, yyleng);
  48
  49 static char *fetch_type_name (char *cp, char const **type_name,
  50                               location dollar_loc);
  51
  52 static void handle_action_dollar (symbol_list *rule, char *cp,
  53                                   location dollar_loc);
  54 static void handle_action_at (symbol_list *rule, char *cp, location at_loc);
  55
  56 /* A string to be pushed to obstack after dollar/at has been handled. */
  57 static char *ref_tail_fields;
  58
  59 static location the_location;
  60 static location *loc = &the_location;
  61
  62 /* A string representing the most recent translation.  */
  63 static char *last_string;
  64
  65 /* True if an untyped $$ or $n was seen.  */
  66 static bool untyped_var_seen;
  67
  68 %}
  69  /* C and C++ comments in code. */
  70 %x SC_COMMENT SC_LINE_COMMENT
  71  /* Strings and characters in code. */
  72 %x SC_STRING SC_CHARACTER
  73  /* Whether in a rule or symbol action.  Specifies the translation
  74     of $ and @.  */
  75 %x SC_RULE_ACTION SC_SYMBOL_ACTION
  76
  77
  78 /* POSIX says that a tag must be both an id and a C union member, but
  79    historically almost any character is allowed in a tag.  We disallow
  80    NUL and newline, as this simplifies our implementation.  */
  81 tag      [^\0\n>]+
  82
  83 /* Zero or more instances of backslash-newline.  Following GCC, allow
  84    white space between the backslash and the newline.  */
  85 splice   (\\[ \f\t\v]*\n)*
  86
  87 /* C style identifier. Must start with letter. Will be used for
  88    named symbol references. Shall be kept synchronized with
  89    scan-gram.l "letter" and "id". */
  90 letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
  91 id        {letter}({letter}|[-0-9])*
  92 ref      -?[0-9]+|{id}|"["{id}"]"|"$"
  93
  94 %%
  95
  96 %{
  97   /* Nesting level of the current code in braces.  */
  98   int braces_level = 0;
  99
 100   /* Whether a semicolon is probably needed.
 101
 102      The heuristic is that a semicolon is not needed after '{', '}',
 103      ';', or a C preprocessor directive, and that whitespaces and
 104      comments do not affect this flag.  Note that '{' does not need a
 105      semicolon because of '{}'.  A semicolon may be needed before a
 106      cpp directive, but don't bother.
 107
 108      While it is maintained in several start-conditions (factoring
 109      opportunities), it is meaningful only for SC_RULE_ACTION. */
 110   bool need_semicolon = false;
 111
 112   /* Whether in a C preprocessor directive.  Don't use a start condition
 113      for this because, at the end of strings and comments, we still need
 114      to know whether we're in a directive.  */
 115   bool in_cpp = false;
 116
 117   /* This scanner is special: it is invoked only once, henceforth
 118      is expected to return only once.  This initialization is
 119      therefore done once per action to translate. */
 120   aver (sc_context == SC_SYMBOL_ACTION
 121         || sc_context == SC_RULE_ACTION
 122         || sc_context == INITIAL);
 123   BEGIN sc_context;
 124 %}
 125
 126   /*------------------------------------------------------------.
 127   | Scanning a C comment.  The initial '/ *' is already eaten.  |
 128   `------------------------------------------------------------*/
 129
 130 <SC_COMMENT>
 131 {
 132   "*"{splice}"/"  STRING_GROW; BEGIN sc_context;
 133 }
 134
 135
 136   /*--------------------------------------------------------------.
 137   | Scanning a line comment.  The initial '//' is already eaten.  |
 138   `--------------------------------------------------------------*/
 139
 140 <SC_LINE_COMMENT>
 141 {
 142   "\n"           STRING_GROW; BEGIN sc_context;
 143   {splice}       STRING_GROW;
 144 }
 145
 146
 147   /*--------------------------------------------.
 148   | Scanning user-code characters and strings.  |
 149   `--------------------------------------------*/
 150
 151 <SC_CHARACTER,SC_STRING>
 152 {
 153   {splice}|\\{splice}.  STRING_GROW;
 154 }
 155
 156 <SC_CHARACTER>
 157 {
 158   "'"           STRING_GROW; BEGIN sc_context;
 159 }
 160
 161 <SC_STRING>
 162 {
 163   "\""          STRING_GROW; BEGIN sc_context;
 164 }
 165
 166
 167 <SC_RULE_ACTION,SC_SYMBOL_ACTION>
 168 {
 169   "'" {
 170     STRING_GROW;
 171     BEGIN SC_CHARACTER;
 172     need_semicolon = true;
 173   }
 174   "\"" {
 175     STRING_GROW;
 176     BEGIN SC_STRING;
 177     need_semicolon = true;
 178   }
 179   "/"{splice}"*" {
 180     STRING_GROW;
 181     BEGIN SC_COMMENT;
 182   }
 183   "/"{splice}"/" {
 184     STRING_GROW;
 185     BEGIN SC_LINE_COMMENT;
 186   }
 187   [$@]  {
 188     warn_at (*loc, _("stray '%s'"), yytext);
 189     obstack_escape (&obstack_for_string, yytext);
 190     need_semicolon = true;
 191   }
 192   [\[\]]  {
 193     obstack_escape (&obstack_for_string, yytext);
 194     need_semicolon = true;
 195   }
 196 }
 197
 198 <SC_RULE_ACTION>
 199 {
 200   "$"("<"{tag}">")?{ref}  {
 201     ref_tail_fields = NULL;
 202     handle_action_dollar (self->rule, yytext, *loc);
 203     if (ref_tail_fields)
 204       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 205     need_semicolon = true;
 206   }
 207   "@"{ref} {
 208     ref_tail_fields = NULL;
 209     handle_action_at (self->rule, yytext, *loc);
 210     if (ref_tail_fields)
 211       obstack_sgrow (&obstack_for_string, ref_tail_fields);
 212     need_semicolon = true;
 213   }
 214
 215   ";"  STRING_GROW;                 need_semicolon = false;
 216   "{"  STRING_GROW; ++braces_level; need_semicolon = false;
 217   "}"  {
 218     bool outer_brace = --braces_level == 0;
 219
 220     /* As an undocumented Bison extension, append ';' before the last
 221        brace in braced code, so that the user code can omit trailing
 222        ';'.  But do not append ';' if emulating Yacc, since Yacc does
 223        not append one.  */
 224     if (outer_brace && !yacc_flag && language_prio == default_prio
 225         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
 226       {
 227         warn_at (*loc, _("a ';' might be needed at the end of action code"));
 228         warn_at (*loc, _("future versions of Bison will not add the ';'"));
 229         obstack_1grow (&obstack_for_string, ';');
 230       }
 231
 232     STRING_GROW;
 233     need_semicolon = false;
 234   }
 235
 236   /* Preprocessing directives should only be recognized at the beginning
 237      of lines, allowing whitespace including comments, but in C/C++,
 238      '#' can only be the start of preprocessor directives or within
 239      '#define' directives anyway, so don't bother with begin of line.  */
 240   "#"       STRING_GROW; in_cpp = true;
 241
 242   {splice}  STRING_GROW;
 243   [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;
 244   [ \t\f]   STRING_GROW;
 245
 246   /* YYFAIL is undocumented and was formally deprecated in Bison
 247      2.4.2.  */
 248   YYFAIL {
 249     STRING_GROW; need_semicolon = true;
 250     warn_at (*loc, _("use of YYFAIL, which is deprecated and will be"
 251                      " removed"));
 252   }
 253
 254   /* The sole purpose of this is to make sure identifiers that merely
 255      contain YYFAIL don't produce the above warning.  */
 256   [A-Za-z_][0-9A-Za-z_]* STRING_GROW; need_semicolon = true;
 257
 258   . STRING_GROW; need_semicolon = true;
 259 }
 260
 261 <SC_SYMBOL_ACTION>
 262 {
 263   "$"("<"{tag}">")?"$" {
 264     const char *type_name = NULL;
 265     fetch_type_name (yytext + 1, &type_name, *loc)[-1] = 0;
 266     obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar(");
 267     obstack_quote (&obstack_for_string, type_name);
 268     obstack_sgrow (&obstack_for_string, ")[");
 269     self->is_value_used = true;
 270   }
 271   "@$" {
 272     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
 273     locations_flag = true;
 274   }
 275 }
 276
 277
 278 <*>
 279 {
 280   /* Escape M4 quoting characters in C code.  */
 281   [$@\[\]]    obstack_escape (&obstack_for_string, yytext);
 282
 283   /* By default, grow the string obstack with the input.  */
 284   .|\n        STRING_GROW;
 285
 286   /* End of processing. */
 287   <<EOF>>     STRING_FINISH; return last_string;
 288 }
 289
 290 %%
 291
 292 static inline bool
 293 is_dot_or_dash (char ch)
 294 {
 295   return ch == '.' || ch == '-';
 296 }
 297
 298 static inline bool
 299 contains_dot_or_dash (const char* p)
 300 {
 301   for (; *p; ++p)
 302     if (is_dot_or_dash (*p))
 303       return true;
 304   return false;
 305 }
 306
 307 /* Defines a variant of a symbolic name resolution. */
 308 typedef struct
 309 {
 310   /* Index in symbol list. */
 311   unsigned symbol_index;
 312
 313   /* Matched symbol id and loc. */
 314   uniqstr id;
 315   location loc;
 316
 317   /* Hiding named reference. */
 318   named_ref* hidden_by;
 319
 320   /* Error flags. May contain zero (no errors) or
 321      a combination of VARIANT_* values. */
 322   unsigned err;
 323 } variant;
 324
 325 /* Set when the variant refers to a symbol hidden
 326    by an explicit symbol reference. */
 327 #define VARIANT_HIDDEN (1 << 0)
 328
 329 /* Set when the variant refers to a symbol containing
 330    dots or dashes. Will require explicit bracketing. */
 331 #define VARIANT_BAD_BRACKETING (1 << 1)
 332
 333 /* Set when the variant refers to a symbol which is
 334    not visible from current midrule. */
 335 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 336
 337 static variant *variant_table = NULL;
 338 static unsigned variant_table_size = 0;
 339 static unsigned variant_count = 0;
 340
 341 static variant *
 342 variant_table_grow (void)
 343 {
 344   ++variant_count;
 345   if (variant_count > variant_table_size)
 346     {
 347       while (variant_count > variant_table_size)
 348         variant_table_size = 2 * variant_table_size + 3;
 349       variant_table = xnrealloc (variant_table, variant_table_size,
 350                                  sizeof *variant_table);
 351     }
 352   return &variant_table[variant_count - 1];
 353 }
 354
 355 static void
 356 variant_table_free (void)
 357 {
 358   free (variant_table);
 359   variant_table = NULL;
 360   variant_table_size = variant_count = 0;
 361 }
 362
 363 static char *
 364 find_prefix_end (const char *prefix, char *begin, char *end)
 365 {
 366   char *ptr = begin;
 367
 368   for (; *prefix && ptr != end; ++prefix, ++ptr)
 369     if (*prefix != *ptr)
 370       return 0;
 371
 372   if (*prefix)
 373     return 0;
 374
 375   return ptr;
 376 }
 377
 378 static variant *
 379 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 380              char *cp, char *cp_end, bool explicit_bracketing)
 381 {
 382   char *prefix_end;
 383
 384   prefix_end = find_prefix_end (id, cp, cp_end);
 385   if (prefix_end &&
 386       (prefix_end == cp_end ||
 387        (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
 388     {
 389       variant *r = variant_table_grow ();
 390       r->symbol_index = symbol_index;
 391       r->id = id;
 392       r->loc = id_loc;
 393       r->hidden_by = NULL;
 394       r->err = 0;
 395       return r;
 396     }
 397   else
 398     return NULL;
 399 }
 400
 401 static const char *
 402 get_at_spec (unsigned symbol_index)
 403 {
 404   static char at_buf[20];
 405   if (symbol_index == 0)
 406     strcpy (at_buf, "$$");
 407   else
 408     snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
 409   return at_buf;
 410 }
 411
 412 static void
 413 show_sub_messages (const char* cp, bool explicit_bracketing,
 414                    int midrule_rhs_index, char dollar_or_at,
 415                    bool is_warning, unsigned indent)
 416 {
 417   unsigned i;
 418
 419   for (i = 0; i < variant_count; ++i)
 420     {
 421       const variant *var = &variant_table[i];
 422       const char *at_spec = get_at_spec (var->symbol_index);
 423
 424       if (var->err == 0)
 425         {
 426           if (is_warning)
 427             warn_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 428                             dollar_or_at, var->id, at_spec);
 429           else
 430             complain_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 431                                 dollar_or_at, var->id, at_spec);
 432         }
 433       else
 434         {
 435           static struct obstack msg_buf;
 436           const char *tail = explicit_bracketing ? "" :
 437             cp + strlen (var->id);
 438           const char *id = var->hidden_by ? var->hidden_by->id :
 439             var->id;
 440           location id_loc = var->hidden_by ? var->hidden_by->loc :
 441             var->loc;
 442
 443           /* Create the explanation message. */
 444           obstack_init (&msg_buf);
 445
 446           obstack_fgrow1 (&msg_buf, _("possibly meant: %c"), dollar_or_at);
 447           if (contains_dot_or_dash (id))
 448             obstack_fgrow1 (&msg_buf, "[%s]", id);
 449           else
 450             obstack_sgrow (&msg_buf, id);
 451           obstack_sgrow (&msg_buf, tail);
 452
 453           if (var->err & VARIANT_HIDDEN)
 454             {
 455               obstack_fgrow1 (&msg_buf, _(", hiding %c"), dollar_or_at);
 456               if (contains_dot_or_dash (var->id))
 457                 obstack_fgrow1 (&msg_buf, "[%s]", var->id);
 458               else
 459                 obstack_sgrow (&msg_buf, var->id);
 460               obstack_sgrow (&msg_buf, tail);
 461             }
 462
 463           obstack_fgrow1 (&msg_buf, _(" at %s"), at_spec);
 464
 465           if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 466             {
 467               const char *format =
 468                 _(", cannot be accessed from mid-rule action at $%d");
 469               obstack_fgrow1 (&msg_buf, format, midrule_rhs_index);
 470             }
 471
 472           obstack_1grow (&msg_buf, '\0');
 473           if (is_warning)
 474             warn_at_indent (id_loc, &indent, "%s",
 475                             (char *) obstack_finish (&msg_buf));
 476           else
 477             complain_at_indent (id_loc, &indent, "%s",
 478                                 (char *) obstack_finish (&msg_buf));
 479           obstack_free (&msg_buf, 0);
 480         }
 481     }
 482 }
 483
 484 /* Returned from "parse_ref" when the reference
 485    is inappropriate. */
 486 #define INVALID_REF (INT_MIN)
 487
 488 /* Returned from "parse_ref" when the reference
 489    points to LHS ($$) of the current rule or midrule. */
 490 #define LHS_REF (INT_MIN + 1)
 491
 492 /* Sub-messages indent. */
 493 #define SUB_INDENT (4)
 494
 495 /* Parse named or positional reference. In case of positional
 496    references, can return negative values for $-n "deep" stack
 497    accesses. */
 498 static long int
 499 parse_ref (char *cp, symbol_list *rule, int rule_length,
 500            int midrule_rhs_index, char *text, location text_loc,
 501            char dollar_or_at)
 502 {
 503   symbol_list *l;
 504   char *cp_end;
 505   bool explicit_bracketing;
 506   unsigned i;
 507   unsigned valid_variants = 0;
 508   unsigned valid_variant_index = 0;
 509
 510   if ('$' == *cp)
 511     return LHS_REF;
 512
 513   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 514     {
 515       long int num = strtol (cp, &cp, 10);
 516       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 517         return num;
 518       else
 519         {
 520           complain_at (text_loc, _("integer out of range: %s"),
 521                        quote (text));
 522           return INVALID_REF;
 523         }
 524     }
 525
 526   if ('[' == *cp)
 527     {
 528       /* Ignore the brackets. */
 529       char *p;
 530       for (p = ++cp; *p != ']'; ++p)
 531         continue;
 532       cp_end = p;
 533
 534       explicit_bracketing = true;
 535     }
 536   else
 537     {
 538       /* Take all characters of the name. */
 539       char* p;
 540       for (p = cp; *p; ++p)
 541         if (is_dot_or_dash (*p))
 542           {
 543             ref_tail_fields = p;
 544             break;
 545           }
 546       for (p = cp; *p; ++p)
 547         continue;
 548       cp_end = p;
 549
 550       explicit_bracketing = false;
 551     }
 552
 553   /* Add all relevant variants. */
 554   {
 555     unsigned symbol_index;
 556     variant_count = 0;
 557     for (symbol_index = 0, l = rule; !symbol_list_null (l);
 558          ++symbol_index, l = l->next)
 559       {
 560         variant *var;
 561         if (l->content_type != SYMLIST_SYMBOL)
 562           continue;
 563
 564         var = variant_add (l->content.sym->tag, l->sym_loc,
 565                            symbol_index, cp, cp_end, explicit_bracketing);
 566         if (var && l->named_ref)
 567           var->hidden_by = l->named_ref;
 568
 569         if (l->named_ref)
 570           variant_add (l->named_ref->id, l->named_ref->loc,
 571                        symbol_index, cp, cp_end, explicit_bracketing);
 572       }
 573   }
 574
 575   /* Check errors. */
 576   for (i = 0; i < variant_count; ++i)
 577     {
 578       variant *var = &variant_table[i];
 579       unsigned symbol_index = var->symbol_index;
 580
 581       /* Check visibility from mid-rule actions. */
 582       if (midrule_rhs_index != 0
 583           && (symbol_index == 0 || midrule_rhs_index < symbol_index))
 584         var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 585
 586       /* Check correct bracketing. */
 587       if (!explicit_bracketing && contains_dot_or_dash (var->id))
 588         var->err |= VARIANT_BAD_BRACKETING;
 589
 590       /* Check using of hidden symbols. */
 591       if (var->hidden_by)
 592         var->err |= VARIANT_HIDDEN;
 593
 594       if (!var->err)
 595         {
 596           valid_variant_index = i;
 597           ++valid_variants;
 598         }
 599     }
 600
 601   switch (valid_variants)
 602     {
 603     case 0:
 604       {
 605         unsigned len = (explicit_bracketing || !ref_tail_fields) ?
 606           cp_end - cp : ref_tail_fields - cp;
 607         unsigned indent = 0;
 608
 609         complain_at_indent (text_loc, &indent, _("invalid reference: %s"),
 610                             quote (text));
 611         indent += SUB_INDENT;
 612         if (len == 0)
 613           {
 614             location sym_loc = text_loc;
 615             sym_loc.start.column += 1;
 616             sym_loc.end = sym_loc.start;
 617             const char *format =
 618               _("syntax error after '%c', expecting integer, letter,"
 619                 " '_', '[', or '$'");
 620             complain_at_indent (sym_loc, &indent, format, dollar_or_at);
 621           }
 622         else if (midrule_rhs_index)
 623           {
 624             const char *format =
 625               _("symbol not found in production before $%d: %.*s");
 626             complain_at_indent (rule->location, &indent, format,
 627                                 midrule_rhs_index, len, cp);
 628           }
 629         else
 630           {
 631             const char *format =
 632               _("symbol not found in production: %.*s");
 633             complain_at_indent (rule->location, &indent, format,
 634                                 len, cp);
 635           }
 636
 637         if (variant_count > 0)
 638           show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 639                              dollar_or_at, false, indent);
 640         return INVALID_REF;
 641       }
 642     case 1:
 643       {
 644         unsigned indent = 0;
 645         if (variant_count > 1)
 646           {
 647             warn_at_indent (text_loc, &indent, _("misleading reference: %s"),
 648                             quote (text));
 649             show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 650                                dollar_or_at, true, indent + SUB_INDENT);
 651           }
 652         {
 653           unsigned symbol_index =
 654             variant_table[valid_variant_index].symbol_index;
 655           return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
 656         }
 657       }
 658     case 2:
 659     default:
 660       {
 661         unsigned indent = 0;
 662         complain_at_indent (text_loc, &indent, _("ambiguous reference: %s"),
 663                             quote (text));
 664         show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 665                            dollar_or_at, false, indent + SUB_INDENT);
 666         return INVALID_REF;
 667       }
 668     }
 669
 670   /* Not reachable. */
 671   return INVALID_REF;
 672 }
 673
 674 /* Keeps track of the maximum number of semantic values to the left of
 675    a handle (those referenced by $0, $-1, etc.) are required by the
 676    semantic actions of this grammar. */
 677 int max_left_semantic_context = 0;
 678
 679
 680 /* If CP points to a typename (i.e., <.*?>), set TYPE_NAME to its
 681    beginning (i.e., after the opening "<", and return the pointer
 682    immediately after it.  */
 683
 684 static
 685 char *
 686 fetch_type_name (char *cp, char const **type_name,
 687                  location dollar_loc)
 688 {
 689   if (*cp == '<')
 690     {
 691       *type_name = ++cp;
 692       while (*cp != '>')
 693         ++cp;
 694
 695       /* The '>' symbol will be later replaced by '\0'. Original
 696          'text' is needed for error messages. */
 697       ++cp;
 698       if (untyped_var_seen)
 699         complain_at (dollar_loc, _("explicit type given in untyped grammar"));
 700       tag_seen = true;
 701     }
 702   return cp;
 703 }
 704
 705 /*------------------------------------------------------------------.
 706 | TEXT is pointing to a wannabee semantic value (i.e., a '$').      |
 707 |                                                                   |
 708 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 709 |                                                                   |
 710 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 711 `------------------------------------------------------------------*/
 712
 713 static void
 714 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 715 {
 716   char const *type_name = NULL;
 717   char *cp = text + 1;
 718   symbol_list *effective_rule;
 719   int effective_rule_length;
 720   int n;
 721
 722   if (rule->midrule_parent_rule)
 723     {
 724       effective_rule = rule->midrule_parent_rule;
 725       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 726     }
 727   else
 728     {
 729       effective_rule = rule;
 730       effective_rule_length = symbol_list_length (rule->next);
 731     }
 732
 733   /* Get the type name if explicit. */
 734   cp = fetch_type_name (cp, &type_name, dollar_loc);
 735
 736   n = parse_ref (cp, effective_rule, effective_rule_length,
 737                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 738
 739   /* End type_name. */
 740   if (type_name)
 741     cp[-1] = '\0';
 742
 743   switch (n)
 744     {
 745     case INVALID_REF:
 746       break;
 747
 748     case LHS_REF:
 749       if (!type_name)
 750         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 751
 752       if (!type_name)
 753         {
 754           if (union_seen | tag_seen)
 755             {
 756               if (rule->midrule_parent_rule)
 757                 complain_at (dollar_loc,
 758                              _("$$ for the midrule at $%d of %s"
 759                                " has no declared type"),
 760                              rule->midrule_parent_rhs_index,
 761                              quote (effective_rule->content.sym->tag));
 762               else
 763                 complain_at (dollar_loc, _("$$ of %s has no declared type"),
 764                              quote (rule->content.sym->tag));
 765             }
 766           else
 767             untyped_var_seen = true;
 768         }
 769
 770       obstack_sgrow (&obstack_for_string, "]b4_lhs_value(");
 771       obstack_quote (&obstack_for_string, type_name);
 772       obstack_sgrow (&obstack_for_string, ")[");
 773       rule->action_props.is_value_used = true;
 774       break;
 775
 776     default:
 777       if (max_left_semantic_context < 1 - n)
 778         max_left_semantic_context = 1 - n;
 779       if (!type_name && 0 < n)
 780         type_name =
 781           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 782       if (!type_name)
 783         {
 784           if (union_seen | tag_seen)
 785             complain_at (dollar_loc, _("$%s of %s has no declared type"),
 786                          cp, quote (effective_rule->content.sym->tag));
 787           else
 788             untyped_var_seen = true;
 789         }
 790
 791       obstack_fgrow2 (&obstack_for_string,
 792                       "]b4_rhs_value(%d, %d, ", effective_rule_length, n);
 793       obstack_quote (&obstack_for_string, type_name);
 794       obstack_sgrow (&obstack_for_string, ")[");
 795       if (n > 0)
 796         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 797           true;
 798       break;
 799     }
 800 }
 801
 802
 803 /*------------------------------------------------------.
 804 | TEXT is a location token (i.e., a '@...').  Output to |
 805 | OBSTACK_FOR_STRING a reference to this location.      |
 806 `------------------------------------------------------*/
 807
 808 static void
 809 handle_action_at (symbol_list *rule, char *text, location at_loc)
 810 {
 811   char *cp = text + 1;
 812   symbol_list *effective_rule;
 813   int effective_rule_length;
 814   int n;
 815
 816   if (rule->midrule_parent_rule)
 817     {
 818       effective_rule = rule->midrule_parent_rule;
 819       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 820     }
 821   else
 822     {
 823       effective_rule = rule;
 824       effective_rule_length = symbol_list_length (rule->next);
 825     }
 826
 827   locations_flag = true;
 828
 829   n = parse_ref (cp, effective_rule, effective_rule_length,
 830                  rule->midrule_parent_rhs_index, text, at_loc, '@');
 831   switch (n)
 832     {
 833     case INVALID_REF:
 834       break;
 835
 836     case LHS_REF:
 837       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 838       break;
 839
 840     default:
 841       obstack_fgrow2 (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 842                       effective_rule_length, n);
 843       break;
 844     }
 845 }
 846
 847
 848 /*-------------------------.
 849 | Initialize the scanner.  |
 850 `-------------------------*/
 851
 852 /* Translate the dollars and ats in \a self, in the context \a sc_context
 853    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 854
 855 static char const *
 856 translate_action (code_props *self, int sc_context)
 857 {
 858   char *res;
 859   static bool initialized = false;
 860   if (!initialized)
 861     {
 862       obstack_init (&obstack_for_string);
 863       yy_flex_debug = 0;
 864       initialized = true;
 865     }
 866
 867   loc->start = loc->end = self->location.start;
 868   yy_switch_to_buffer (yy_scan_string (self->code));
 869   res = code_lex (self, sc_context);
 870   yy_delete_buffer (YY_CURRENT_BUFFER);
 871
 872   return res;
 873 }
 874
 875 /*------------------------------------------------------------------------.
 876 | Implementation of the public interface as documented in "scan-code.h".  |
 877 `------------------------------------------------------------------------*/
 878
 879 void
 880 code_props_none_init (code_props *self)
 881 {
 882   *self = code_props_none;
 883 }
 884
 885 code_props const code_props_none = CODE_PROPS_NONE_INIT;
 886
 887 void
 888 code_props_plain_init (code_props *self, char const *code,
 889                        location code_loc)
 890 {
 891   self->kind = CODE_PROPS_PLAIN;
 892   self->code = code;
 893   self->location = code_loc;
 894   self->is_value_used = false;
 895   self->rule = NULL;
 896   self->named_ref = NULL;
 897 }
 898
 899 void
 900 code_props_symbol_action_init (code_props *self, char const *code,
 901                                location code_loc)
 902 {
 903   self->kind = CODE_PROPS_SYMBOL_ACTION;
 904   self->code = code;
 905   self->location = code_loc;
 906   self->is_value_used = false;
 907   self->rule = NULL;
 908   self->named_ref = NULL;
 909 }
 910
 911 void
 912 code_props_rule_action_init (code_props *self, char const *code,
 913                              location code_loc, symbol_list *rule,
 914                              named_ref *name)
 915 {
 916   self->kind = CODE_PROPS_RULE_ACTION;
 917   self->code = code;
 918   self->location = code_loc;
 919   self->is_value_used = false;
 920   self->rule = rule;
 921   self->named_ref = name;
 922 }
 923
 924 void
 925 code_props_translate_code (code_props *self)
 926 {
 927   switch (self->kind)
 928     {
 929       case CODE_PROPS_NONE:
 930         break;
 931       case CODE_PROPS_PLAIN:
 932         self->code = translate_action (self, INITIAL);
 933         break;
 934       case CODE_PROPS_SYMBOL_ACTION:
 935         self->code = translate_action (self, SC_SYMBOL_ACTION);
 936         break;
 937       case CODE_PROPS_RULE_ACTION:
 938         self->code = translate_action (self, SC_RULE_ACTION);
 939         break;
 940     }
 941 }
 942
 943 void
 944 code_scanner_last_string_free (void)
 945 {
 946   STRING_FREE;
 947 }
 948
 949 void
 950 code_scanner_free (void)
 951 {
 952   obstack_free (&obstack_for_string, 0);
 953   variant_table_free ();
 954
 955   /* Reclaim Flex's buffers.  */
 956   yylex_destroy ();
 957 }