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 "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.  This is deprecated since release 2.4.1.  */
 224     if (outer_brace && !yacc_flag && language_prio == default_prio
 225         && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
 226       {
 227         unsigned int indent = 0;
 228         warn_at_indent (*loc, &indent,
 229                        _("a ';' might be needed at the end of action code"));
 230         indent += SUB_INDENT;
 231         warn_at_indent (*loc, &indent,
 232                        _("future versions of Bison will not add the ';'"));
 233         obstack_1grow (&obstack_for_string, ';');
 234       }
 235
 236     STRING_GROW;
 237     need_semicolon = false;
 238   }
 239
 240   /* Preprocessing directives should only be recognized at the beginning
 241      of lines, allowing whitespace including comments, but in C/C++,
 242      '#' can only be the start of preprocessor directives or within
 243      '#define' directives anyway, so don't bother with begin of line.  */
 244   "#"       STRING_GROW; in_cpp = true;
 245
 246   {splice}  STRING_GROW;
 247   [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;
 248   [ \t\f]   STRING_GROW;
 249
 250   /* YYFAIL is undocumented and was formally deprecated in Bison
 251      2.4.2.  */
 252   YYFAIL {
 253     STRING_GROW; need_semicolon = true;
 254     warn_at (*loc, _("use of YYFAIL, which is deprecated and will be"
 255                      " removed"));
 256   }
 257
 258   /* The sole purpose of this is to make sure identifiers that merely
 259      contain YYFAIL don't produce the above warning.  */
 260   [A-Za-z_][0-9A-Za-z_]* STRING_GROW; need_semicolon = true;
 261
 262   . STRING_GROW; need_semicolon = true;
 263 }
 264
 265 <SC_SYMBOL_ACTION>
 266 {
 267   "$"("<"{tag}">")?"$" {
 268     const char *type_name = NULL;
 269     fetch_type_name (yytext + 1, &type_name, *loc)[-1] = 0;
 270     obstack_sgrow (&obstack_for_string, "]b4_dollar_dollar(");
 271     obstack_quote (&obstack_for_string, type_name);
 272     obstack_sgrow (&obstack_for_string, ")[");
 273     self->is_value_used = true;
 274   }
 275   "@$" {
 276     obstack_sgrow (&obstack_for_string, "]b4_at_dollar[");
 277     locations_flag = true;
 278   }
 279 }
 280
 281
 282 <*>
 283 {
 284   /* Escape M4 quoting characters in C code.  */
 285   [$@\[\]]    obstack_escape (&obstack_for_string, yytext);
 286
 287   /* By default, grow the string obstack with the input.  */
 288   .|\n        STRING_GROW;
 289
 290   /* End of processing. */
 291   <<EOF>>     STRING_FINISH; return last_string;
 292 }
 293
 294 %%
 295
 296 static inline bool
 297 is_dot_or_dash (char ch)
 298 {
 299   return ch == '.' || ch == '-';
 300 }
 301
 302 static inline bool
 303 contains_dot_or_dash (const char* p)
 304 {
 305   for (; *p; ++p)
 306     if (is_dot_or_dash (*p))
 307       return true;
 308   return false;
 309 }
 310
 311 /* Defines a variant of a symbolic name resolution. */
 312 typedef struct
 313 {
 314   /* Index in symbol list. */
 315   unsigned symbol_index;
 316
 317   /* Matched symbol id and loc. */
 318   uniqstr id;
 319   location loc;
 320
 321   /* Hiding named reference. */
 322   named_ref* hidden_by;
 323
 324   /* Error flags. May contain zero (no errors) or
 325      a combination of VARIANT_* values. */
 326   unsigned err;
 327 } variant;
 328
 329 /* Set when the variant refers to a symbol hidden
 330    by an explicit symbol reference. */
 331 #define VARIANT_HIDDEN (1 << 0)
 332
 333 /* Set when the variant refers to a symbol containing
 334    dots or dashes. Will require explicit bracketing. */
 335 #define VARIANT_BAD_BRACKETING (1 << 1)
 336
 337 /* Set when the variant refers to a symbol which is
 338    not visible from current midrule. */
 339 #define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
 340
 341 static variant *variant_table = NULL;
 342 static unsigned variant_table_size = 0;
 343 static unsigned variant_count = 0;
 344
 345 static variant *
 346 variant_table_grow (void)
 347 {
 348   ++variant_count;
 349   if (variant_count > variant_table_size)
 350     {
 351       while (variant_count > variant_table_size)
 352         variant_table_size = 2 * variant_table_size + 3;
 353       variant_table = xnrealloc (variant_table, variant_table_size,
 354                                  sizeof *variant_table);
 355     }
 356   return &variant_table[variant_count - 1];
 357 }
 358
 359 static void
 360 variant_table_free (void)
 361 {
 362   free (variant_table);
 363   variant_table = NULL;
 364   variant_table_size = variant_count = 0;
 365 }
 366
 367 static char *
 368 find_prefix_end (const char *prefix, char *begin, char *end)
 369 {
 370   char *ptr = begin;
 371
 372   for (; *prefix && ptr != end; ++prefix, ++ptr)
 373     if (*prefix != *ptr)
 374       return 0;
 375
 376   if (*prefix)
 377     return 0;
 378
 379   return ptr;
 380 }
 381
 382 static variant *
 383 variant_add (uniqstr id, location id_loc, unsigned symbol_index,
 384              char *cp, char *cp_end, bool explicit_bracketing)
 385 {
 386   char *prefix_end;
 387
 388   prefix_end = find_prefix_end (id, cp, cp_end);
 389   if (prefix_end &&
 390       (prefix_end == cp_end ||
 391        (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
 392     {
 393       variant *r = variant_table_grow ();
 394       r->symbol_index = symbol_index;
 395       r->id = id;
 396       r->loc = id_loc;
 397       r->hidden_by = NULL;
 398       r->err = 0;
 399       return r;
 400     }
 401   else
 402     return NULL;
 403 }
 404
 405 static const char *
 406 get_at_spec (unsigned symbol_index)
 407 {
 408   static char at_buf[20];
 409   if (symbol_index == 0)
 410     strcpy (at_buf, "$$");
 411   else
 412     snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
 413   return at_buf;
 414 }
 415
 416 static void
 417 show_sub_messages (const char* cp, bool explicit_bracketing,
 418                    int midrule_rhs_index, char dollar_or_at,
 419                    bool is_warning, unsigned indent)
 420 {
 421   unsigned i;
 422
 423   for (i = 0; i < variant_count; ++i)
 424     {
 425       const variant *var = &variant_table[i];
 426       const char *at_spec = get_at_spec (var->symbol_index);
 427
 428       if (var->err == 0)
 429         {
 430           if (is_warning)
 431             warn_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 432                             dollar_or_at, var->id, at_spec);
 433           else
 434             complain_at_indent (var->loc, &indent, _("refers to: %c%s at %s"),
 435                                 dollar_or_at, var->id, at_spec);
 436         }
 437       else
 438         {
 439           static struct obstack msg_buf;
 440           const char *tail = explicit_bracketing ? "" :
 441             cp + strlen (var->id);
 442           const char *id = var->hidden_by ? var->hidden_by->id :
 443             var->id;
 444           location id_loc = var->hidden_by ? var->hidden_by->loc :
 445             var->loc;
 446
 447           /* Create the explanation message. */
 448           obstack_init (&msg_buf);
 449
 450           obstack_printf (&msg_buf, _("possibly meant: %c"), dollar_or_at);
 451           if (contains_dot_or_dash (id))
 452             obstack_printf (&msg_buf, "[%s]", id);
 453           else
 454             obstack_sgrow (&msg_buf, id);
 455           obstack_sgrow (&msg_buf, tail);
 456
 457           if (var->err & VARIANT_HIDDEN)
 458             {
 459               obstack_printf (&msg_buf, _(", hiding %c"), dollar_or_at);
 460               if (contains_dot_or_dash (var->id))
 461                 obstack_printf (&msg_buf, "[%s]", var->id);
 462               else
 463                 obstack_sgrow (&msg_buf, var->id);
 464               obstack_sgrow (&msg_buf, tail);
 465             }
 466
 467           obstack_printf (&msg_buf, _(" at %s"), at_spec);
 468
 469           if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
 470             {
 471               const char *format =
 472                 _(", cannot be accessed from mid-rule action at $%d");
 473               obstack_printf (&msg_buf, format, midrule_rhs_index);
 474             }
 475
 476           obstack_1grow (&msg_buf, '\0');
 477           if (is_warning)
 478             warn_at_indent (id_loc, &indent, "%s",
 479                             (char *) obstack_finish (&msg_buf));
 480           else
 481             complain_at_indent (id_loc, &indent, "%s",
 482                                 (char *) obstack_finish (&msg_buf));
 483           obstack_free (&msg_buf, 0);
 484         }
 485     }
 486 }
 487
 488 /* Returned from "parse_ref" when the reference
 489    is inappropriate. */
 490 #define INVALID_REF (INT_MIN)
 491
 492 /* Returned from "parse_ref" when the reference
 493    points to LHS ($$) of the current rule or midrule. */
 494 #define LHS_REF (INT_MIN + 1)
 495
 496 /* Parse named or positional reference. In case of positional
 497    references, can return negative values for $-n "deep" stack
 498    accesses. */
 499 static long int
 500 parse_ref (char *cp, symbol_list *rule, int rule_length,
 501            int midrule_rhs_index, char *text, location text_loc,
 502            char dollar_or_at)
 503 {
 504   symbol_list *l;
 505   char *cp_end;
 506   bool explicit_bracketing;
 507   unsigned i;
 508   unsigned valid_variants = 0;
 509   unsigned valid_variant_index = 0;
 510
 511   if ('$' == *cp)
 512     return LHS_REF;
 513
 514   if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
 515     {
 516       long int num = strtol (cp, &cp, 10);
 517       if (1 - INT_MAX + rule_length <= num && num <= rule_length)
 518         return num;
 519       else
 520         {
 521           complain_at (text_loc, _("integer out of range: %s"),
 522                        quote (text));
 523           return INVALID_REF;
 524         }
 525     }
 526
 527   if ('[' == *cp)
 528     {
 529       /* Ignore the brackets. */
 530       char *p;
 531       for (p = ++cp; *p != ']'; ++p)
 532         continue;
 533       cp_end = p;
 534
 535       explicit_bracketing = true;
 536     }
 537   else
 538     {
 539       /* Take all characters of the name. */
 540       char* p;
 541       for (p = cp; *p; ++p)
 542         if (is_dot_or_dash (*p))
 543           {
 544             ref_tail_fields = p;
 545             break;
 546           }
 547       for (p = cp; *p; ++p)
 548         continue;
 549       cp_end = p;
 550
 551       explicit_bracketing = false;
 552     }
 553
 554   /* Add all relevant variants. */
 555   {
 556     unsigned symbol_index;
 557     variant_count = 0;
 558     for (symbol_index = 0, l = rule; !symbol_list_null (l);
 559          ++symbol_index, l = l->next)
 560       {
 561         variant *var;
 562         if (l->content_type != SYMLIST_SYMBOL)
 563           continue;
 564
 565         var = variant_add (l->content.sym->tag, l->sym_loc,
 566                            symbol_index, cp, cp_end, explicit_bracketing);
 567         if (var && l->named_ref)
 568           var->hidden_by = l->named_ref;
 569
 570         if (l->named_ref)
 571           variant_add (l->named_ref->id, l->named_ref->loc,
 572                        symbol_index, cp, cp_end, explicit_bracketing);
 573       }
 574   }
 575
 576   /* Check errors. */
 577   for (i = 0; i < variant_count; ++i)
 578     {
 579       variant *var = &variant_table[i];
 580       unsigned symbol_index = var->symbol_index;
 581
 582       /* Check visibility from mid-rule actions. */
 583       if (midrule_rhs_index != 0
 584           && (symbol_index == 0 || midrule_rhs_index < symbol_index))
 585         var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
 586
 587       /* Check correct bracketing. */
 588       if (!explicit_bracketing && contains_dot_or_dash (var->id))
 589         var->err |= VARIANT_BAD_BRACKETING;
 590
 591       /* Check using of hidden symbols. */
 592       if (var->hidden_by)
 593         var->err |= VARIANT_HIDDEN;
 594
 595       if (!var->err)
 596         {
 597           valid_variant_index = i;
 598           ++valid_variants;
 599         }
 600     }
 601
 602   switch (valid_variants)
 603     {
 604     case 0:
 605       {
 606         unsigned len = (explicit_bracketing || !ref_tail_fields) ?
 607           cp_end - cp : ref_tail_fields - cp;
 608         unsigned indent = 0;
 609
 610         complain_at_indent (text_loc, &indent, _("invalid reference: %s"),
 611                             quote (text));
 612         indent += SUB_INDENT;
 613         if (len == 0)
 614           {
 615             location sym_loc = text_loc;
 616             sym_loc.start.column += 1;
 617             sym_loc.end = sym_loc.start;
 618             const char *format =
 619               _("syntax error after '%c', expecting integer, letter,"
 620                 " '_', '[', or '$'");
 621             complain_at_indent (sym_loc, &indent, format, dollar_or_at);
 622           }
 623         else if (midrule_rhs_index)
 624           {
 625             const char *format =
 626               _("symbol not found in production before $%d: %.*s");
 627             complain_at_indent (rule->location, &indent, format,
 628                                 midrule_rhs_index, len, cp);
 629           }
 630         else
 631           {
 632             const char *format =
 633               _("symbol not found in production: %.*s");
 634             complain_at_indent (rule->location, &indent, format,
 635                                 len, cp);
 636           }
 637
 638         if (variant_count > 0)
 639           show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 640                              dollar_or_at, false, indent);
 641         return INVALID_REF;
 642       }
 643     case 1:
 644       {
 645         unsigned indent = 0;
 646         if (variant_count > 1)
 647           {
 648             warn_at_indent (text_loc, &indent, _("misleading reference: %s"),
 649                             quote (text));
 650             show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 651                                dollar_or_at, true, indent + SUB_INDENT);
 652           }
 653         {
 654           unsigned symbol_index =
 655             variant_table[valid_variant_index].symbol_index;
 656           return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
 657         }
 658       }
 659     case 2:
 660     default:
 661       {
 662         unsigned indent = 0;
 663         complain_at_indent (text_loc, &indent, _("ambiguous reference: %s"),
 664                             quote (text));
 665         show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
 666                            dollar_or_at, false, indent + SUB_INDENT);
 667         return INVALID_REF;
 668       }
 669     }
 670
 671   /* Not reachable. */
 672   return INVALID_REF;
 673 }
 674
 675 /* Keeps track of the maximum number of semantic values to the left of
 676    a handle (those referenced by $0, $-1, etc.) are required by the
 677    semantic actions of this grammar. */
 678 int max_left_semantic_context = 0;
 679
 680
 681 /* If CP points to a typename (i.e., <.*?>), set TYPE_NAME to its
 682    beginning (i.e., after the opening "<", and return the pointer
 683    immediately after it.  */
 684
 685 static
 686 char *
 687 fetch_type_name (char *cp, char const **type_name,
 688                  location dollar_loc)
 689 {
 690   if (*cp == '<')
 691     {
 692       *type_name = ++cp;
 693       while (*cp != '>')
 694         ++cp;
 695
 696       /* The '>' symbol will be later replaced by '\0'. Original
 697          'text' is needed for error messages. */
 698       ++cp;
 699       if (untyped_var_seen)
 700         complain_at (dollar_loc, _("explicit type given in untyped grammar"));
 701       tag_seen = true;
 702     }
 703   return cp;
 704 }
 705
 706 /*------------------------------------------------------------------.
 707 | TEXT is pointing to a wannabee semantic value (i.e., a '$').      |
 708 |                                                                   |
 709 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 710 |                                                                   |
 711 | Output to OBSTACK_FOR_STRING a reference to this semantic value.  |
 712 `------------------------------------------------------------------*/
 713
 714 static void
 715 handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
 716 {
 717   char const *type_name = NULL;
 718   char *cp = text + 1;
 719   symbol_list *effective_rule;
 720   int effective_rule_length;
 721   int n;
 722
 723   if (rule->midrule_parent_rule)
 724     {
 725       effective_rule = rule->midrule_parent_rule;
 726       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 727     }
 728   else
 729     {
 730       effective_rule = rule;
 731       effective_rule_length = symbol_list_length (rule->next);
 732     }
 733
 734   /* Get the type name if explicit. */
 735   cp = fetch_type_name (cp, &type_name, dollar_loc);
 736
 737   n = parse_ref (cp, effective_rule, effective_rule_length,
 738                  rule->midrule_parent_rhs_index, text, dollar_loc, '$');
 739
 740   /* End type_name. */
 741   if (type_name)
 742     cp[-1] = '\0';
 743
 744   switch (n)
 745     {
 746     case INVALID_REF:
 747       break;
 748
 749     case LHS_REF:
 750       if (!type_name)
 751         type_name = symbol_list_n_type_name_get (rule, dollar_loc, 0);
 752
 753       if (!type_name)
 754         {
 755           if (union_seen | tag_seen)
 756             {
 757               if (rule->midrule_parent_rule)
 758                 complain_at (dollar_loc,
 759                              _("$$ for the midrule at $%d of %s"
 760                                " has no declared type"),
 761                              rule->midrule_parent_rhs_index,
 762                              quote (effective_rule->content.sym->tag));
 763               else
 764                 complain_at (dollar_loc, _("$$ of %s has no declared type"),
 765                              quote (rule->content.sym->tag));
 766             }
 767           else
 768             untyped_var_seen = true;
 769         }
 770
 771       obstack_sgrow (&obstack_for_string, "]b4_lhs_value(");
 772       obstack_quote (&obstack_for_string, type_name);
 773       obstack_sgrow (&obstack_for_string, ")[");
 774       rule->action_props.is_value_used = true;
 775       break;
 776
 777     default:
 778       if (max_left_semantic_context < 1 - n)
 779         max_left_semantic_context = 1 - n;
 780       if (!type_name && 0 < n)
 781         type_name =
 782           symbol_list_n_type_name_get (effective_rule, dollar_loc, n);
 783       if (!type_name)
 784         {
 785           if (union_seen | tag_seen)
 786             complain_at (dollar_loc, _("$%s of %s has no declared type"),
 787                          cp, quote (effective_rule->content.sym->tag));
 788           else
 789             untyped_var_seen = true;
 790         }
 791
 792       obstack_printf (&obstack_for_string,
 793                       "]b4_rhs_value(%d, %d, ", effective_rule_length, n);
 794       obstack_quote (&obstack_for_string, type_name);
 795       obstack_sgrow (&obstack_for_string, ")[");
 796       if (n > 0)
 797         symbol_list_n_get (effective_rule, n)->action_props.is_value_used =
 798           true;
 799       break;
 800     }
 801 }
 802
 803
 804 /*------------------------------------------------------.
 805 | TEXT is a location token (i.e., a '@...').  Output to |
 806 | OBSTACK_FOR_STRING a reference to this location.      |
 807 `------------------------------------------------------*/
 808
 809 static void
 810 handle_action_at (symbol_list *rule, char *text, location at_loc)
 811 {
 812   char *cp = text + 1;
 813   symbol_list *effective_rule;
 814   int effective_rule_length;
 815   int n;
 816
 817   if (rule->midrule_parent_rule)
 818     {
 819       effective_rule = rule->midrule_parent_rule;
 820       effective_rule_length = rule->midrule_parent_rhs_index - 1;
 821     }
 822   else
 823     {
 824       effective_rule = rule;
 825       effective_rule_length = symbol_list_length (rule->next);
 826     }
 827
 828   locations_flag = true;
 829
 830   n = parse_ref (cp, effective_rule, effective_rule_length,
 831                  rule->midrule_parent_rhs_index, text, at_loc, '@');
 832   switch (n)
 833     {
 834     case INVALID_REF:
 835       break;
 836
 837     case LHS_REF:
 838       obstack_sgrow (&obstack_for_string, "]b4_lhs_location[");
 839       break;
 840
 841     default:
 842       obstack_printf (&obstack_for_string, "]b4_rhs_location(%d, %d)[",
 843                       effective_rule_length, n);
 844       break;
 845     }
 846 }
 847
 848
 849 /*-------------------------.
 850 | Initialize the scanner.  |
 851 `-------------------------*/
 852
 853 /* Translate the dollars and ats in \a self, in the context \a sc_context
 854    (SC_RULE_ACTION, SC_SYMBOL_ACTION, INITIAL).  */
 855
 856 static char const *
 857 translate_action (code_props *self, int sc_context)
 858 {
 859   char *res;
 860   static bool initialized = false;
 861   if (!initialized)
 862     {
 863       obstack_init (&obstack_for_string);
 864       yy_flex_debug = 0;
 865       initialized = true;
 866     }
 867
 868   loc->start = loc->end = self->location.start;
 869   yy_switch_to_buffer (yy_scan_string (self->code));
 870   res = code_lex (self, sc_context);
 871   yy_delete_buffer (YY_CURRENT_BUFFER);
 872
 873   return res;
 874 }
 875
 876 /*------------------------------------------------------------------------.
 877 | Implementation of the public interface as documented in "scan-code.h".  |
 878 `------------------------------------------------------------------------*/
 879
 880 void
 881 code_props_none_init (code_props *self)
 882 {
 883   *self = code_props_none;
 884 }
 885
 886 code_props const code_props_none = CODE_PROPS_NONE_INIT;
 887
 888 void
 889 code_props_plain_init (code_props *self, char const *code,
 890                        location code_loc)
 891 {
 892   self->kind = CODE_PROPS_PLAIN;
 893   self->code = code;
 894   self->location = code_loc;
 895   self->is_value_used = false;
 896   self->rule = NULL;
 897   self->named_ref = NULL;
 898 }
 899
 900 void
 901 code_props_symbol_action_init (code_props *self, char const *code,
 902                                location code_loc)
 903 {
 904   self->kind = CODE_PROPS_SYMBOL_ACTION;
 905   self->code = code;
 906   self->location = code_loc;
 907   self->is_value_used = false;
 908   self->rule = NULL;
 909   self->named_ref = NULL;
 910 }
 911
 912 void
 913 code_props_rule_action_init (code_props *self, char const *code,
 914                              location code_loc, symbol_list *rule,
 915                              named_ref *name)
 916 {
 917   self->kind = CODE_PROPS_RULE_ACTION;
 918   self->code = code;
 919   self->location = code_loc;
 920   self->is_value_used = false;
 921   self->rule = rule;
 922   self->named_ref = name;
 923 }
 924
 925 void
 926 code_props_translate_code (code_props *self)
 927 {
 928   switch (self->kind)
 929     {
 930       case CODE_PROPS_NONE:
 931         break;
 932       case CODE_PROPS_PLAIN:
 933         self->code = translate_action (self, INITIAL);
 934         break;
 935       case CODE_PROPS_SYMBOL_ACTION:
 936         self->code = translate_action (self, SC_SYMBOL_ACTION);
 937         break;
 938       case CODE_PROPS_RULE_ACTION:
 939         self->code = translate_action (self, SC_RULE_ACTION);
 940         break;
 941     }
 942 }
 943
 944 void
 945 code_scanner_last_string_free (void)
 946 {
 947   STRING_FREE;
 948 }
 949
 950 void
 951 code_scanner_free (void)
 952 {
 953   obstack_free (&obstack_for_string, 0);
 954   variant_table_free ();
 955
 956   /* Reclaim Flex's buffers.  */
 957   yylex_destroy ();
 958 }