src/scan-gram.l

   1 /* Bison Grammar Scanner                             -*- C -*-
   2    Copyright (C) 2002 Free Software Foundation, Inc.
   3
   4    This file is part of Bison, the GNU Compiler Compiler.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307  USA
  20 */
  21
  22 %option debug nodefault noyywrap never-interactive
  23 %option prefix="gram_" outfile="lex.yy.c"
  24
  25 %{
  26 #include "system.h"
  27 #include "mbswidth.h"
  28 #include "complain.h"
  29 #include "quote.h"
  30 #include "struniq.h"
  31 #include "getargs.h"
  32 #include "gram.h"
  33 #include "reader.h"
  34
  35 /* Each time we match a string, move the end cursor to its end. */
  36 #define YY_USER_INIT                            \
  37 do {                                            \
  38   LOCATION_RESET (*yylloc);                     \
  39   yylloc->file = infile;                        \
  40    /* This is only to avoid GCC warnings. */    \
  41   if (yycontrol) {;};                           \
  42 } while (0)
  43
  44 #define YY_USER_ACTION  extend_location (yylloc, yytext, yyleng);
  45 #define YY_STEP         LOCATION_STEP (*yylloc)
  46
  47 #define YY_INPUT(buf, result, size) ((result) = no_cr_read (yyin, buf, size))
  48
  49
  50 /* Read bytes from FP into buffer BUF of size SIZE.  Return the
  51    number of bytes read.  Remove '\r' from input, treating \r\n
  52    and isolated \r as \n.  */
  53
  54 static size_t
  55 no_cr_read (FILE *fp, char *buf, size_t size)
  56 {
  57   size_t s = fread (buf, 1, size, fp);
  58   if (s)
  59     {
  60       char *w = memchr (buf, '\r', s);
  61       if (w)
  62         {
  63           char const *r = ++w;
  64           char const *lim = buf + s;
  65
  66           for (;;)
  67             {
  68               /* Found an '\r'.  Treat it like '\n', but ignore any
  69                  '\n' that immediately follows.  */
  70               w[-1] = '\n';
  71               if (r == lim)
  72                 {
  73                   int ch = getc (fp);
  74                   if (ch != '\n' && ungetc (ch, fp) != ch)
  75                     break;
  76                 }
  77               else if (*r == '\n')
  78                 r++;
  79
  80               /* Copy until the next '\r'.  */
  81               do
  82                 {
  83                   if (r == lim)
  84                     return w - buf;
  85                 }
  86               while ((*w++ = *r++) != '\r');
  87             }
  88
  89           return w - buf;
  90         }
  91     }
  92
  93   return s;
  94 }
  95
  96
  97 /* Extend *LOC to account for token TOKEN of size SIZE.  */
  98
  99 static void
 100 extend_location (location_t *loc, char const *token, int size)
 101 {
 102   int line = loc->last_line;
 103   int column = loc->last_column;
 104   char const *p0 = token;
 105   char const *p = token;
 106   char const *lim = token + size;
 107
 108   for (p = token; p < lim; p++)
 109     switch (*p)
 110       {
 111       case '\r':
 112         /* \r shouldn't survive no_cr_read.  */
 113         abort ();
 114
 115       case '\n':
 116         line++;
 117         column = 1;
 118         p0 = p + 1;
 119         break;
 120
 121       case '\t':
 122         column += mbsnwidth (p0, p - p0, 0);
 123         column += 8 - ((column - 1) & 7);
 124         p0 = p + 1;
 125         break;
 126       }
 127
 128   loc->last_line = line;
 129   loc->last_column = column + mbsnwidth (p0, p - p0, 0);
 130 }
 131
 132
 133
 134 /* STRING_OBSTACK -- Used to store all the characters that we need to
 135    keep (to construct ID, STRINGS etc.).  Use the following macros to
 136    use it.
 137
 138    Use YY_OBS_GROW to append what has just been matched, and
 139    YY_OBS_FINISH to end the string (it puts the ending 0).
 140    YY_OBS_FINISH also stores this string in LAST_STRING, which can be
 141    used, and which is used by YY_OBS_FREE to free the last string.  */
 142
 143 static struct obstack string_obstack;
 144
 145 #define YY_OBS_GROW   \
 146   obstack_grow (&string_obstack, yytext, yyleng)
 147
 148 #define YY_OBS_FINISH                                   \
 149   do {                                                  \
 150     obstack_1grow (&string_obstack, '\0');              \
 151     last_string = obstack_finish (&string_obstack);     \
 152   } while (0)
 153
 154 #define YY_OBS_FREE \
 155   obstack_free (&string_obstack, last_string)
 156
 157
 158 /* Within well-formed rules, RULE_LENGTH is the number of values in
 159    the current rule so far, which says where to find `$0' with respect
 160    to the top of the stack.  It is not the same as the rule->length in
 161    the case of mid rule actions.
 162
 163    Outside of well-formed rules, RULE_LENGTH has an undefined value.  */
 164 static int rule_length;
 165
 166 static void handle_dollar (braced_code_t code_kind,
 167                            char *cp, location_t location);
 168 static void handle_at (braced_code_t code_kind,
 169                        char *cp, location_t location);
 170 static void handle_syncline (char *args, location_t *location);
 171 static int convert_ucn_to_byte (char const *hex_text);
 172 static void unexpected_end_of_file (location_t *, char const *);
 173
 174 %}
 175 %x SC_COMMENT SC_LINE_COMMENT SC_YACC_COMMENT
 176 %x SC_STRING SC_CHARACTER
 177 %x SC_ESCAPED_STRING SC_ESCAPED_CHARACTER
 178 %x SC_BRACED_CODE SC_PROLOGUE SC_EPILOGUE
 179
 180 letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
 181 id        {letter}({letter}|[0-9])*
 182 directive %{letter}({letter}|[0-9]|-)*
 183 int       [0-9]+
 184
 185 /* POSIX says that a tag must be both an id and a C union member, but
 186    historically almost any character is allowed in a tag.  We disallow
 187    NUL and newline, as this simplifies our implementation.  */
 188 tag      [^\0\n>]+
 189
 190 /* Zero or more instances of backslash-newline.  Following GCC, allow
 191    white space between the backslash and the newline.  */
 192 splice   (\\[ \f\t\v]*\n)*
 193
 194 %%
 195 %{
 196   /* Nesting level of the current code in braces.  */
 197   int braces_level IF_LINT (= 0);
 198
 199   /* Scanner context when scanning C code.  */
 200   int c_context IF_LINT (= 0);
 201
 202   /* A string representing the most recently saved token.  */
 203   char *last_string;
 204
 205   /* At each yylex invocation, mark the current position as the
 206      start of the next token.  */
 207   YY_STEP;
 208 %}
 209
 210
 211   /*----------------------------.
 212   | Scanning Bison directives.  |
 213   `----------------------------*/
 214 <INITIAL>
 215 {
 216   "%binary"               return PERCENT_NONASSOC;
 217   "%debug"                return PERCENT_DEBUG;
 218   "%define"               return PERCENT_DEFINE;
 219   "%defines"              return PERCENT_DEFINES;
 220   "%destructor"           return PERCENT_DESTRUCTOR;
 221   "%dprec"                return PERCENT_DPREC;
 222   "%error"[-_]"verbose"   return PERCENT_ERROR_VERBOSE;
 223   "%expect"               return PERCENT_EXPECT;
 224   "%file-prefix"          return PERCENT_FILE_PREFIX;
 225   "%fixed"[-_]"output"[-_]"files"   return PERCENT_YACC;
 226   "%glr-parser"           return PERCENT_GLR_PARSER;
 227   "%left"                 return PERCENT_LEFT;
 228   "%locations"            return PERCENT_LOCATIONS;
 229   "%merge"                return PERCENT_MERGE;
 230   "%name"[-_]"prefix"     return PERCENT_NAME_PREFIX;
 231   "%no"[-_]"lines"        return PERCENT_NO_LINES;
 232   "%nonassoc"             return PERCENT_NONASSOC;
 233   "%nterm"                return PERCENT_NTERM;
 234   "%output"               return PERCENT_OUTPUT;
 235   "%parse-param"          return PERCENT_PARSE_PARAM;
 236   "%prec"                 rule_length--; return PERCENT_PREC;
 237   "%printer"              return PERCENT_PRINTER;
 238   "%pure"[-_]"parser"     return PERCENT_PURE_PARSER;
 239   "%right"                return PERCENT_RIGHT;
 240   "%lex-param"            return PERCENT_LEX_PARAM;
 241   "%skeleton"             return PERCENT_SKELETON;
 242   "%start"                return PERCENT_START;
 243   "%term"                 return PERCENT_TOKEN;
 244   "%token"                return PERCENT_TOKEN;
 245   "%token"[-_]"table"     return PERCENT_TOKEN_TABLE;
 246   "%type"                 return PERCENT_TYPE;
 247   "%union"                return PERCENT_UNION;
 248   "%verbose"              return PERCENT_VERBOSE;
 249   "%yacc"                 return PERCENT_YACC;
 250
 251   {directive}             {
 252     complain_at (*yylloc, _("invalid directive: %s"), quote (yytext));
 253     YY_STEP;
 254   }
 255
 256   ^"#line "{int}" \""[^\"]*"\"\n"   handle_syncline (yytext + strlen ("#line "), yylloc); YY_STEP;
 257
 258   "="                     return EQUAL;
 259   ":"                     rule_length = 0; return COLON;
 260   "|"                     rule_length = 0; return PIPE;
 261   ","                     return COMMA;
 262   ";"                     return SEMICOLON;
 263
 264   [ \f\n\t\v]  YY_STEP;
 265
 266   {id}        {
 267     yylval->symbol = symbol_get (yytext, *yylloc);
 268     rule_length++;
 269     return ID;
 270   }
 271
 272   {int} {
 273     unsigned long num;
 274     errno = 0;
 275     num = strtoul (yytext, 0, 10);
 276     if (INT_MAX < num || errno)
 277       {
 278         complain_at (*yylloc, _("integer out of range: %s"), quote (yytext));
 279         num = INT_MAX;
 280       }
 281     yylval->integer = num;
 282     return INT;
 283   }
 284
 285   /* Characters.  We don't check there is only one.  */
 286   "'"         YY_OBS_GROW; BEGIN SC_ESCAPED_CHARACTER;
 287
 288   /* Strings. */
 289   "\""        YY_OBS_GROW; BEGIN SC_ESCAPED_STRING;
 290
 291   /* Comments. */
 292   "/*"        BEGIN SC_YACC_COMMENT;
 293   "//".*      YY_STEP;
 294
 295   /* Prologue. */
 296   "%{"        BEGIN SC_PROLOGUE;
 297
 298   /* Code in between braces.  */
 299   "{"         YY_OBS_GROW; braces_level = 0; BEGIN SC_BRACED_CODE;
 300
 301   /* A type. */
 302   "<"{tag}">" {
 303     obstack_grow (&string_obstack, yytext + 1, yyleng - 2);
 304     YY_OBS_FINISH;
 305     yylval->struniq = struniq_new (last_string);
 306     YY_OBS_FREE;
 307     return TYPE;
 308   }
 309
 310   "%%" {
 311     static int percent_percent_count;
 312     if (++percent_percent_count == 2)
 313       BEGIN SC_EPILOGUE;
 314     return PERCENT_PERCENT;
 315   }
 316
 317   . {
 318     complain_at (*yylloc, _("invalid character: %s"), quote (yytext));
 319     YY_STEP;
 320   }
 321 }
 322
 323
 324   /*---------------------------------------------------------------.
 325   | Scanning a Yacc comment.  The initial `/ *' is already eaten.  |
 326   `---------------------------------------------------------------*/
 327
 328 <SC_YACC_COMMENT>
 329 {
 330   "*/" {
 331     YY_STEP;
 332     BEGIN INITIAL;
 333   }
 334
 335   .|\n     ;
 336   <<EOF>>  unexpected_end_of_file (yylloc, "*/");
 337 }
 338
 339
 340   /*------------------------------------------------------------.
 341   | Scanning a C comment.  The initial `/ *' is already eaten.  |
 342   `------------------------------------------------------------*/
 343
 344 <SC_COMMENT>
 345 {
 346   "*"{splice}"/"  YY_OBS_GROW; BEGIN c_context;
 347   <<EOF>>         unexpected_end_of_file (yylloc, "*/");
 348 }
 349
 350
 351   /*--------------------------------------------------------------.
 352   | Scanning a line comment.  The initial `//' is already eaten.  |
 353   `--------------------------------------------------------------*/
 354
 355 <SC_LINE_COMMENT>
 356 {
 357   "\n"           YY_OBS_GROW; BEGIN c_context;
 358   {splice}       YY_OBS_GROW;
 359   <<EOF>>        BEGIN c_context;
 360 }
 361
 362
 363   /*----------------------------------------------------------------.
 364   | Scanning a C string, including its escapes.  The initial `"' is |
 365   | already eaten.                                                  |
 366   `----------------------------------------------------------------*/
 367
 368 <SC_ESCAPED_STRING>
 369 {
 370   "\"" {
 371     YY_OBS_GROW;
 372     YY_OBS_FINISH;
 373     yylval->string = last_string;
 374     rule_length++;
 375     BEGIN INITIAL;
 376     return STRING;
 377   }
 378
 379   .|\n      YY_OBS_GROW;
 380   <<EOF>>   unexpected_end_of_file (yylloc, "\"");
 381 }
 382
 383   /*---------------------------------------------------------------.
 384   | Scanning a C character, decoding its escapes.  The initial "'" |
 385   | is already eaten.                                              |
 386   `---------------------------------------------------------------*/
 387
 388 <SC_ESCAPED_CHARACTER>
 389 {
 390   "'" {
 391     YY_OBS_GROW;
 392     YY_OBS_FINISH;
 393     yylval->symbol = symbol_get (last_string, *yylloc);
 394     symbol_class_set (yylval->symbol, token_sym, *yylloc);
 395     symbol_user_token_number_set (yylval->symbol,
 396                                   (unsigned char) last_string[1], *yylloc);
 397     YY_OBS_FREE;
 398     rule_length++;
 399     BEGIN INITIAL;
 400     return ID;
 401   }
 402
 403   .|\n      YY_OBS_GROW;
 404   <<EOF>>   unexpected_end_of_file (yylloc, "'");
 405 }
 406
 407
 408   /*----------------------------.
 409   | Decode escaped characters.  |
 410   `----------------------------*/
 411
 412 <SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>
 413 {
 414   \\[0-7]{1,3} {
 415     unsigned long c = strtoul (yytext + 1, 0, 8);
 416     if (UCHAR_MAX < c)
 417       {
 418         complain_at (*yylloc, _("invalid escape sequence: %s"),
 419                      quote (yytext));
 420         YY_STEP;
 421       }
 422     else
 423       obstack_1grow (&string_obstack, c);
 424   }
 425
 426   \\x[0-9a-fA-F]+ {
 427     unsigned long c;
 428     errno = 0;
 429     c = strtoul (yytext + 2, 0, 16);
 430     if (UCHAR_MAX < c || errno)
 431       {
 432         complain_at (*yylloc, _("invalid escape sequence: %s"),
 433                      quote (yytext));
 434         YY_STEP;
 435       }
 436     else
 437       obstack_1grow (&string_obstack, c);
 438   }
 439
 440   \\a   obstack_1grow (&string_obstack, '\a');
 441   \\b   obstack_1grow (&string_obstack, '\b');
 442   \\f   obstack_1grow (&string_obstack, '\f');
 443   \\n   obstack_1grow (&string_obstack, '\n');
 444   \\r   obstack_1grow (&string_obstack, '\r');
 445   \\t   obstack_1grow (&string_obstack, '\t');
 446   \\v   obstack_1grow (&string_obstack, '\v');
 447   \\[\"\'?\\]  obstack_1grow (&string_obstack, yytext[1]);
 448   \\(u|U[0-9a-fA-F]{4})[0-9a-fA-F]{4} {
 449     int c = convert_ucn_to_byte (yytext);
 450     if (c < 0)
 451       {
 452         complain_at (*yylloc, _("invalid escape sequence: %s"),
 453                      quote (yytext));
 454         YY_STEP;
 455       }
 456     else
 457       obstack_1grow (&string_obstack, c);
 458   }
 459   \\(.|\n)      {
 460     complain_at (*yylloc, _("unrecognized escape sequence: %s"),
 461                  quote (yytext));
 462     YY_OBS_GROW;
 463   }
 464 }
 465
 466
 467   /*----------------------------------------------------------.
 468   | Scanning a C character without decoding its escapes.  The |
 469   | initial "'" is already eaten.                             |
 470   `----------------------------------------------------------*/
 471
 472 <SC_CHARACTER>
 473 {
 474   "'"               YY_OBS_GROW; BEGIN c_context;
 475   \\{splice}[\'\\]  YY_OBS_GROW;
 476   <<EOF>>           unexpected_end_of_file (yylloc, "'");
 477 }
 478
 479
 480   /*----------------------------------------------------------------.
 481   | Scanning a C string, without decoding its escapes.  The initial |
 482   | `"' is already eaten.                                           |
 483   `----------------------------------------------------------------*/
 484
 485 <SC_STRING>
 486 {
 487   "\""              YY_OBS_GROW; BEGIN c_context;
 488   \\{splice}[\"\\]  YY_OBS_GROW;
 489   <<EOF>>           unexpected_end_of_file (yylloc, "\"");
 490 }
 491
 492
 493   /*---------------------------------------------------.
 494   | Strings, comments etc. can be found in user code.  |
 495   `---------------------------------------------------*/
 496
 497 <SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
 498 {
 499   "'"             YY_OBS_GROW; c_context = YY_START; BEGIN SC_CHARACTER;
 500   "\""            YY_OBS_GROW; c_context = YY_START; BEGIN SC_STRING;
 501   "/"{splice}"*"  YY_OBS_GROW; c_context = YY_START; BEGIN SC_COMMENT;
 502   "/"{splice}"/"  YY_OBS_GROW; c_context = YY_START; BEGIN SC_LINE_COMMENT;
 503 }
 504
 505
 506   /*---------------------------------------------------------------.
 507   | Scanning some code in braces (%union and actions). The initial |
 508   | "{" is already eaten.                                          |
 509   `---------------------------------------------------------------*/
 510
 511 <SC_BRACED_CODE>
 512 {
 513   "{"|"<"{splice}"%"  YY_OBS_GROW; braces_level++;
 514   "%"{splice}">"      YY_OBS_GROW; braces_level--;
 515   "}" {
 516     YY_OBS_GROW;
 517     braces_level--;
 518     if (braces_level < 0)
 519       {
 520         YY_OBS_FINISH;
 521         yylval->string = last_string;
 522         rule_length++;
 523         BEGIN INITIAL;
 524         return BRACED_CODE;
 525       }
 526   }
 527
 528   /* Tokenize `<<%' correctly (as `<<' `%') rather than incorrrectly
 529      (as `<' `<%').  */
 530   "<"{splice}"<"  YY_OBS_GROW;
 531
 532   "$"("<"{tag}">")?(-?[0-9]+|"$") { handle_dollar (current_braced_code,
 533                                                    yytext, *yylloc); }
 534   "@"(-?[0-9]+|"$")               { handle_at (current_braced_code,
 535                                                yytext, *yylloc); }
 536
 537   <<EOF>>  unexpected_end_of_file (yylloc, "}");
 538 }
 539
 540
 541   /*--------------------------------------------------------------.
 542   | Scanning some prologue: from "%{" (already scanned) to "%}".  |
 543   `--------------------------------------------------------------*/
 544
 545 <SC_PROLOGUE>
 546 {
 547   "%}" {
 548     YY_OBS_FINISH;
 549     yylval->string = last_string;
 550     BEGIN INITIAL;
 551     return PROLOGUE;
 552   }
 553
 554   <<EOF>>  unexpected_end_of_file (yylloc, "%}");
 555 }
 556
 557
 558   /*---------------------------------------------------------------.
 559   | Scanning the epilogue (everything after the second "%%", which |
 560   | has already been eaten).                                       |
 561   `---------------------------------------------------------------*/
 562
 563 <SC_EPILOGUE>
 564 {
 565   <<EOF>> {
 566     YY_OBS_FINISH;
 567     yylval->string = last_string;
 568     BEGIN INITIAL;
 569     return EPILOGUE;
 570   }
 571 }
 572
 573
 574   /*----------------------------------------------------------------.
 575   | By default, grow the string obstack with the input, escaping M4 |
 576   | quoting characters.                                             |
 577   `----------------------------------------------------------------*/
 578
 579 <SC_COMMENT,SC_LINE_COMMENT,SC_STRING,SC_CHARACTER,SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
 580 {
 581   \$    obstack_sgrow (&string_obstack, "$][");
 582   \@    obstack_sgrow (&string_obstack, "@@");
 583   \[    obstack_sgrow (&string_obstack, "@{");
 584   \]    obstack_sgrow (&string_obstack, "@}");
 585   .|\n  YY_OBS_GROW;
 586 }
 587
 588
 589 %%
 590
 591 /*------------------------------------------------------------------.
 592 | TEXT is pointing to a wannabee semantic value (i.e., a `$').      |
 593 |                                                                   |
 594 | Possible inputs: $[<TYPENAME>]($|integer)                         |
 595 |                                                                   |
 596 | Output to the STRING_OBSTACK a reference to this semantic value.  |
 597 `------------------------------------------------------------------*/
 598
 599 static inline void
 600 handle_action_dollar (char *text, location_t location)
 601 {
 602   const char *type_name = NULL;
 603   char *cp = text + 1;
 604
 605   /* Get the type name if explicit. */
 606   if (*cp == '<')
 607     {
 608       type_name = ++cp;
 609       while (*cp != '>')
 610         ++cp;
 611       *cp = '\0';
 612       ++cp;
 613     }
 614
 615   if (*cp == '$')
 616     {
 617       if (!type_name)
 618         type_name = symbol_list_n_type_name_get (current_rule, location, 0);
 619       if (!type_name && typed)
 620         complain_at (location, _("$$ of `%s' has no declared type"),
 621                      current_rule->sym->tag);
 622       if (!type_name)
 623         type_name = "";
 624       obstack_fgrow1 (&string_obstack,
 625                       "]b4_lhs_value([%s])[", type_name);
 626     }
 627   else
 628     {
 629       long num;
 630       errno = 0;
 631       num = strtol (cp, 0, 10);
 632
 633       if (INT_MIN <= num && num <= rule_length && ! errno)
 634         {
 635           int n = num;
 636           if (!type_name && n > 0)
 637             type_name = symbol_list_n_type_name_get (current_rule, location,
 638                                                      n);
 639           if (!type_name && typed)
 640             complain_at (location, _("$%d of `%s' has no declared type"),
 641                       n, current_rule->sym->tag);
 642           if (!type_name)
 643             type_name = "";
 644           obstack_fgrow3 (&string_obstack,
 645                           "]b4_rhs_value([%d], [%d], [%s])[",
 646                           rule_length, n, type_name);
 647         }
 648       else
 649         complain_at (location, _("integer out of range: %s"), quote (text));
 650     }
 651 }
 652
 653
 654 /*---------------------------------------------------------------.
 655 | TEXT is expected to be $$ in some code associated to a symbol: |
 656 | destructor or printer.                                         |
 657 `---------------------------------------------------------------*/
 658
 659 static inline void
 660 handle_symbol_code_dollar (char *text, location_t location)
 661 {
 662   char *cp = text + 1;
 663   if (*cp == '$')
 664     obstack_sgrow (&string_obstack, "]b4_dollar_dollar[");
 665   else
 666     complain_at (location, _("invalid value: %s"), quote (text));
 667 }
 668
 669
 670 /*-----------------------------------------------------------------.
 671 | Dispatch onto handle_action_dollar, or handle_destructor_dollar, |
 672 | depending upon CODE_KIND.                                        |
 673 `-----------------------------------------------------------------*/
 674
 675 static void
 676 handle_dollar (braced_code_t braced_code_kind,
 677                char *text, location_t location)
 678 {
 679   switch (braced_code_kind)
 680     {
 681     case action_braced_code:
 682       handle_action_dollar (text, location);
 683       break;
 684
 685     case destructor_braced_code:
 686     case printer_braced_code:
 687       handle_symbol_code_dollar (text, location);
 688       break;
 689     }
 690 }
 691
 692
 693 /*------------------------------------------------------.
 694 | TEXT is a location token (i.e., a `@...').  Output to |
 695 | STRING_OBSTACK a reference to this location.          |
 696 `------------------------------------------------------*/
 697
 698 static inline void
 699 handle_action_at (char *text, location_t location)
 700 {
 701   char *cp = text + 1;
 702   locations_flag = 1;
 703
 704   if (*cp == '$')
 705     {
 706       obstack_sgrow (&string_obstack, "]b4_lhs_location[");
 707     }
 708   else
 709     {
 710       long num;
 711       errno = 0;
 712       num = strtol (cp, 0, 10);
 713
 714       if (INT_MIN <= num && num <= rule_length && ! errno)
 715         {
 716           int n = num;
 717           obstack_fgrow2 (&string_obstack, "]b4_rhs_location([%d], [%d])[",
 718                           rule_length, n);
 719         }
 720       else
 721         complain_at (location, _("integer out of range: %s"), quote (text));
 722     }
 723 }
 724
 725
 726 /*---------------------------------------------------------------.
 727 | TEXT is expected to be @$ in some code associated to a symbol: |
 728 | destructor or printer.                                         |
 729 `---------------------------------------------------------------*/
 730
 731 static inline void
 732 handle_symbol_code_at (char *text, location_t location)
 733 {
 734   char *cp = text + 1;
 735   if (*cp == '$')
 736     obstack_sgrow (&string_obstack, "]b4_at_dollar[");
 737   else
 738     complain_at (location, _("invalid value: %s"), quote (text));
 739 }
 740
 741
 742 /*-------------------------------------------------------------------.
 743 | Dispatch onto handle_action_at, or handle_destructor_at, depending |
 744 | upon CODE_KIND.                                                    |
 745 `-------------------------------------------------------------------*/
 746
 747 static void
 748 handle_at (braced_code_t braced_code_kind,
 749            char *text, location_t location)
 750 {
 751   switch (braced_code_kind)
 752     {
 753     case action_braced_code:
 754       handle_action_at (text, location);
 755       break;
 756
 757     case destructor_braced_code:
 758     case printer_braced_code:
 759       handle_symbol_code_at (text, location);
 760       break;
 761     }
 762 }
 763
 764
 765 /*------------------------------------------------------------------.
 766 | Convert universal character name UCN to a single-byte character,  |
 767 | and return that character.  Return -1 if UCN does not correspond  |
 768 | to a single-byte character.                                       |
 769 `------------------------------------------------------------------*/
 770
 771 static int
 772 convert_ucn_to_byte (char const *ucn)
 773 {
 774   unsigned long code = strtoul (ucn + 2, 0, 16);
 775
 776   /* FIXME: Currently we assume Unicode-compatible unibyte characters
 777      on ASCII hosts (i.e., Latin-1 on hosts with 8-bit bytes).  On
 778      non-ASCII hosts we support only the portable C character set.
 779      These limitations should be removed once we add support for
 780      multibyte characters.  */
 781
 782   if (UCHAR_MAX < code)
 783     return -1;
 784
 785 #if ! ('$' == 0x24 && '@' == 0x40 && '`' == 0x60 && '~' == 0x7e)
 786   {
 787     /* A non-ASCII host.  Use CODE to index into a table of the C
 788        basic execution character set, which is guaranteed to exist on
 789        all Standard C platforms.  This table also includes '$', '@',
 790        and '`', which are not in the basic execution character set but
 791        which are unibyte characters on all the platforms that we know
 792        about.  */
 793     static signed char const table[] =
 794       {
 795         '\0',   -1,   -1,   -1,   -1,   -1,   -1, '\a',
 796         '\b', '\t', '\n', '\v', '\f', '\r',   -1,   -1,
 797           -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
 798           -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
 799          ' ',  '!',  '"',  '#',  '$',  '%',  '&', '\'',
 800          '(',  ')',  '*',  '+',  ',',  '-',  '.',  '/',
 801          '0',  '1',  '2',  '3',  '4',  '5',  '6',  '7',
 802          '8',  '9',  ':',  ';',  '<',  '=',  '>',  '?',
 803          '@',  'A',  'B',  'C',  'D',  'E',  'F',  'G',
 804          'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',
 805          'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',
 806          'X',  'Y',  'Z',  '[', '\\',  ']',  '^',  '_',
 807          '`',  'a',  'b',  'c',  'd',  'e',  'f',  'g',
 808          'h',  'i',  'j',  'k',  'l',  'm',  'n',  'o',
 809          'p',  'q',  'r',  's',  't',  'u',  'v',  'w',
 810          'x',  'y',  'z',  '{',  '|',  '}',  '~'
 811       };
 812
 813     code = code < sizeof table ? table[code] : -1;
 814   }
 815 #endif
 816
 817   return code;
 818 }
 819
 820
 821 /*----------------------------------------------------------------.
 822 | Handle `#line INT "FILE"'.  ARGS has already skipped `#line '.  |
 823 `----------------------------------------------------------------*/
 824
 825 static void
 826 handle_syncline (char *args, location_t *location)
 827 {
 828   int lineno = strtol (args, &args, 10);
 829   const char *file = NULL;
 830   file = strchr (args, '"') + 1;
 831   *strchr (file, '"') = 0;
 832   /* FIXME: Leaking...  Can't free, as some locations are still
 833      pointing to the old file name.  */
 834   infile = xstrdup (file);
 835   location->file = infile;
 836   location->last_line = lineno;
 837 }
 838
 839
 840 /*-------------------------------------------------------------.
 841 | Report an unexpected end of file at LOC.  An end of file was |
 842 | encountered and the expected TOKEN_END was missing.  After   |
 843 | reporting the problem, pretend that TOKEN_END was found.     |
 844 `-------------------------------------------------------------*/
 845
 846 static void
 847 unexpected_end_of_file (location_t *loc, char const *token_end)
 848 {
 849   size_t i = strlen (token_end);
 850
 851   complain_at (*loc, _("missing `%s' at end of file"), token_end);
 852
 853   /* Adjust location's last column so that any later message does not
 854      mention the characters just inserted.  */
 855   loc->last_column -= i;
 856
 857   while (i != 0)
 858     unput (token_end[--i]);
 859 }
 860
 861
 862 /*-------------------------.
 863 | Initialize the scanner.  |
 864 `-------------------------*/
 865
 866 void
 867 scanner_initialize (void)
 868 {
 869   obstack_init (&string_obstack);
 870 }
 871
 872
 873 /*-----------------------------------------------.
 874 | Free all the memory allocated to the scanner.  |
 875 `-----------------------------------------------*/
 876
 877 void
 878 scanner_free (void)
 879 {
 880   obstack_free (&string_obstack, 0);
 881   /* Reclaim Flex's buffers.  */
 882   yy_delete_buffer (YY_CURRENT_BUFFER);
 883 }