src/scan-gram.l

   1 /* Bison Grammar Scanner                             -*- C -*-
   2
   3    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
   4    Inc.
   5
   6    This file is part of Bison, the GNU Compiler Compiler.
   7
   8    This program is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 %option debug nodefault nounput noyywrap never-interactive
  22 %option prefix="gram_" outfile="lex.yy.c"
  23
  24 %{
  25 /* Work around a bug in flex 2.5.31.  See Debian bug 333231
  26    <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=333231>.  */
  27 #undef gram_wrap
  28 #define gram_wrap() 1
  29
  30 #define FLEX_PREFIX(Id) gram_ ## Id
  31 #include "flex-scanner.h"
  32
  33 #include "complain.h"
  34 #include "files.h"
  35 #include "gram.h"
  36 #include "quotearg.h"
  37 #include "reader.h"
  38 #include "uniqstr.h"
  39
  40 #include <mbswidth.h>
  41 #include <quote.h>
  42
  43 #include "scan-gram.h"
  44
  45 #define YY_DECL GRAM_LEX_DECL
  46
  47 #define YY_USER_INIT                                    \
  48    code_start = scanner_cursor = loc->start;            \
  49
  50 /* Location of scanner cursor.  */
  51 static boundary scanner_cursor;
  52
  53 #define YY_USER_ACTION  location_compute (loc, &scanner_cursor, yytext, yyleng);
  54
  55 static size_t no_cr_read (FILE *, char *, size_t);
  56 #define YY_INPUT(buf, result, size) ((result) = no_cr_read (yyin, buf, size))
  57
  58 /* A string representing the most recently saved token.  */
  59 static char *last_string;
  60
  61 void
  62 gram_scanner_last_string_free (void)
  63 {
  64   STRING_FREE;
  65 }
  66
  67 static void handle_syncline (char *, location);
  68 static unsigned long int scan_integer (char const *p, int base, location loc);
  69 static int convert_ucn_to_byte (char const *hex_text);
  70 static void unexpected_eof (boundary, char const *);
  71 static void unexpected_newline (boundary, char const *);
  72
  73 %}
  74  /* A C-like comment in directives/rules. */
  75 %x SC_YACC_COMMENT
  76  /* Strings and characters in directives/rules. */
  77 %x SC_ESCAPED_STRING SC_ESCAPED_CHARACTER
  78  /* A identifier was just read in directives/rules.  Special state
  79     to capture the sequence `identifier :'. */
  80 %x SC_AFTER_IDENTIFIER
  81
  82  /* Three types of user code:
  83     - prologue (code between `%{' `%}' in the first section, before %%);
  84     - actions, printers, union, etc, (between braced in the middle section);
  85     - epilogue (everything after the second %%). */
  86 %x SC_PROLOGUE SC_BRACED_CODE SC_EPILOGUE
  87  /* C and C++ comments in code. */
  88 %x SC_COMMENT SC_LINE_COMMENT
  89  /* Strings and characters in code. */
  90 %x SC_STRING SC_CHARACTER
  91
  92 letter    [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
  93 id        {letter}({letter}|[0-9])*
  94 directive %{letter}({letter}|[0-9]|-)*
  95 int       [0-9]+
  96
  97 /* POSIX says that a tag must be both an id and a C union member, but
  98    historically almost any character is allowed in a tag.  We disallow
  99    NUL and newline, as this simplifies our implementation.  */
 100 tag      [^\0\n>]+
 101
 102 /* Zero or more instances of backslash-newline.  Following GCC, allow
 103    white space between the backslash and the newline.  */
 104 splice   (\\[ \f\t\v]*\n)*
 105
 106 %%
 107 %{
 108   /* Nesting level of the current code in braces.  */
 109   int braces_level IF_LINT (= 0);
 110
 111   /* Parent context state, when applicable.  */
 112   int context_state IF_LINT (= 0);
 113
 114   /* Location of most recent identifier, when applicable.  */
 115   location id_loc IF_LINT (= empty_location);
 116
 117   /* Where containing code started, when applicable.  Its initial
 118      value is relevant only when yylex is invoked in the SC_EPILOGUE
 119      start condition.  */
 120   boundary code_start = scanner_cursor;
 121
 122   /* Where containing comment or string or character literal started,
 123      when applicable.  */
 124   boundary token_start IF_LINT (= scanner_cursor);
 125 %}
 126
 127
 128   /*-----------------------.
 129   | Scanning white space.  |
 130   `-----------------------*/
 131
 132 <INITIAL,SC_AFTER_IDENTIFIER>
 133 {
 134   /* Comments and white space.  */
 135   ","          warn_at (*loc, _("stray `,' treated as white space"));
 136   [ \f\n\t\v]  |
 137   "//".*       ;
 138   "/*" {
 139     token_start = loc->start;
 140     context_state = YY_START;
 141     BEGIN SC_YACC_COMMENT;
 142   }
 143
 144   /* #line directives are not documented, and may be withdrawn or
 145      modified in future versions of Bison.  */
 146   ^"#line "{int}" \"".*"\"\n" {
 147     handle_syncline (yytext + sizeof "#line " - 1, *loc);
 148   }
 149 }
 150
 151
 152   /*----------------------------.
 153   | Scanning Bison directives.  |
 154   `----------------------------*/
 155 <INITIAL>
 156 {
 157   "%binary"                         return PERCENT_NONASSOC;
 158   "%code"                           return PERCENT_CODE;
 159   "%debug"                          return PERCENT_DEBUG;
 160   "%default"[-_]"prec"              return PERCENT_DEFAULT_PREC;
 161   "%define"                         return PERCENT_DEFINE;
 162   "%defines"                        return PERCENT_DEFINES;
 163   "%destructor"                     return PERCENT_DESTRUCTOR;
 164   "%dprec"                          return PERCENT_DPREC;
 165   "%error"[-_]"verbose"             return PERCENT_ERROR_VERBOSE;
 166   "%expect"                         return PERCENT_EXPECT;
 167   "%expect"[-_]"rr"                 return PERCENT_EXPECT_RR;
 168   "%file-prefix"                    return PERCENT_FILE_PREFIX;
 169   "%fixed"[-_]"output"[-_]"files"   return PERCENT_YACC;
 170   "%initial-action"                 return PERCENT_INITIAL_ACTION;
 171   "%glr-parser"                     return PERCENT_GLR_PARSER;
 172   "%language"                       return PERCENT_LANGUAGE;
 173   "%left"                           return PERCENT_LEFT;
 174   "%lex-param"                      return PERCENT_LEX_PARAM;
 175   "%locations"                      return PERCENT_LOCATIONS;
 176   "%merge"                          return PERCENT_MERGE;
 177   "%name"[-_]"prefix"               return PERCENT_NAME_PREFIX;
 178   "%no"[-_]"default"[-_]"prec"      return PERCENT_NO_DEFAULT_PREC;
 179   "%no"[-_]"lines"                  return PERCENT_NO_LINES;
 180   "%nonassoc"                       return PERCENT_NONASSOC;
 181   "%nondeterministic-parser"        return PERCENT_NONDETERMINISTIC_PARSER;
 182   "%nterm"                          return PERCENT_NTERM;
 183   "%output"                         return PERCENT_OUTPUT;
 184   "%parse-param"                    return PERCENT_PARSE_PARAM;
 185   "%prec"                           return PERCENT_PREC;
 186   "%printer"                        return PERCENT_PRINTER;
 187   "%pure"[-_]"parser"               return PERCENT_PURE_PARSER;
 188   "%require"                        return PERCENT_REQUIRE;
 189   "%right"                          return PERCENT_RIGHT;
 190   "%skeleton"                       return PERCENT_SKELETON;
 191   "%start"                          return PERCENT_START;
 192   "%term"                           return PERCENT_TOKEN;
 193   "%token"                          return PERCENT_TOKEN;
 194   "%token"[-_]"table"               return PERCENT_TOKEN_TABLE;
 195   "%type"                           return PERCENT_TYPE;
 196   "%union"                          return PERCENT_UNION;
 197   "%verbose"                        return PERCENT_VERBOSE;
 198   "%yacc"                           return PERCENT_YACC;
 199
 200   {directive} {
 201     complain_at (*loc, _("invalid directive: %s"), quote (yytext));
 202   }
 203
 204   "="                     return EQUAL;
 205   "|"                     return PIPE;
 206   ";"                     return SEMICOLON;
 207   "<*>"                   return TYPE_TAG_ANY;
 208   "<>"                    return TYPE_TAG_NONE;
 209
 210   {id} {
 211     val->uniqstr = uniqstr_new (yytext);
 212     id_loc = *loc;
 213     BEGIN SC_AFTER_IDENTIFIER;
 214   }
 215
 216   {int} {
 217     val->integer = scan_integer (yytext, 10, *loc);
 218     return INT;
 219   }
 220   0[xX][0-9abcdefABCDEF]+ {
 221     val->integer = scan_integer (yytext, 16, *loc);
 222     return INT;
 223   }
 224
 225   /* Characters.  We don't check there is only one.  */
 226   "'"         STRING_GROW; token_start = loc->start; BEGIN SC_ESCAPED_CHARACTER;
 227
 228   /* Strings. */
 229   "\""        token_start = loc->start; BEGIN SC_ESCAPED_STRING;
 230
 231   /* Prologue. */
 232   "%{"        code_start = loc->start; BEGIN SC_PROLOGUE;
 233
 234   /* Code in between braces.  */
 235   "{" {
 236     STRING_GROW;
 237     braces_level = 0;
 238     code_start = loc->start;
 239     BEGIN SC_BRACED_CODE;
 240   }
 241
 242   /* A type. */
 243   "<"{tag}">" {
 244     obstack_grow (&obstack_for_string, yytext + 1, yyleng - 2);
 245     STRING_FINISH;
 246     val->uniqstr = uniqstr_new (last_string);
 247     STRING_FREE;
 248     return TYPE;
 249   }
 250
 251   "%%" {
 252     static int percent_percent_count;
 253     if (++percent_percent_count == 2)
 254       BEGIN SC_EPILOGUE;
 255     return PERCENT_PERCENT;
 256   }
 257
 258   . {
 259     complain_at (*loc, _("invalid character: %s"), quote (yytext));
 260   }
 261
 262   <<EOF>> {
 263     loc->start = loc->end = scanner_cursor;
 264     yyterminate ();
 265   }
 266 }
 267
 268
 269   /*-----------------------------------------------------------------.
 270   | Scanning after an identifier, checking whether a colon is next.  |
 271   `-----------------------------------------------------------------*/
 272
 273 <SC_AFTER_IDENTIFIER>
 274 {
 275   ":" {
 276     *loc = id_loc;
 277     BEGIN INITIAL;
 278     return ID_COLON;
 279   }
 280   . {
 281     scanner_cursor.column -= mbsnwidth (yytext, yyleng, 0);
 282     yyless (0);
 283     *loc = id_loc;
 284     BEGIN INITIAL;
 285     return ID;
 286   }
 287   <<EOF>> {
 288     *loc = id_loc;
 289     BEGIN INITIAL;
 290     return ID;
 291   }
 292 }
 293
 294
 295   /*---------------------------------------------------------------.
 296   | Scanning a Yacc comment.  The initial `/ *' is already eaten.  |
 297   `---------------------------------------------------------------*/
 298
 299 <SC_YACC_COMMENT>
 300 {
 301   "*/"     BEGIN context_state;
 302   .|\n     ;
 303   <<EOF>>  unexpected_eof (token_start, "*/"); BEGIN context_state;
 304 }
 305
 306
 307   /*------------------------------------------------------------.
 308   | Scanning a C comment.  The initial `/ *' is already eaten.  |
 309   `------------------------------------------------------------*/
 310
 311 <SC_COMMENT>
 312 {
 313   "*"{splice}"/"  STRING_GROW; BEGIN context_state;
 314   <<EOF>>         unexpected_eof (token_start, "*/"); BEGIN context_state;
 315 }
 316
 317
 318   /*--------------------------------------------------------------.
 319   | Scanning a line comment.  The initial `//' is already eaten.  |
 320   `--------------------------------------------------------------*/
 321
 322 <SC_LINE_COMMENT>
 323 {
 324   "\n"           STRING_GROW; BEGIN context_state;
 325   {splice}       STRING_GROW;
 326   <<EOF>>        BEGIN context_state;
 327 }
 328
 329
 330   /*------------------------------------------------.
 331   | Scanning a Bison string, including its escapes. |
 332   | The initial quote is already eaten.             |
 333   `------------------------------------------------*/
 334
 335 <SC_ESCAPED_STRING>
 336 {
 337   "\""|"\n" {
 338     if (yytext[0] == '\n')
 339       unexpected_newline (token_start, "\"");
 340     STRING_FINISH;
 341     loc->start = token_start;
 342     val->chars = last_string;
 343     BEGIN INITIAL;
 344     return STRING;
 345   }
 346   <<EOF>> {
 347     unexpected_eof (token_start, "\"");
 348     STRING_FINISH;
 349     loc->start = token_start;
 350     val->chars = last_string;
 351     BEGIN INITIAL;
 352     return STRING;
 353   }
 354 }
 355
 356   /*----------------------------------------------------------.
 357   | Scanning a Bison character literal, decoding its escapes. |
 358   | The initial quote is already eaten.                       |
 359   `----------------------------------------------------------*/
 360
 361 <SC_ESCAPED_CHARACTER>
 362 {
 363   "'"|"\n" {
 364     if (yytext[0] == '\n')
 365       unexpected_newline (token_start, "'");
 366     STRING_GROW;
 367     STRING_FINISH;
 368     loc->start = token_start;
 369     val->character = last_string[1];
 370     STRING_FREE;
 371     BEGIN INITIAL;
 372     return CHAR;
 373   }
 374   <<EOF>> {
 375     unexpected_eof (token_start, "'");
 376     STRING_FINISH;
 377     loc->start = token_start;
 378     if (strlen(last_string) > 1)
 379       val->character = last_string[1];
 380     else
 381       val->character = last_string[0];
 382     STRING_FREE;
 383     BEGIN INITIAL;
 384     return CHAR;
 385   }
 386 }
 387
 388 <SC_ESCAPED_CHARACTER,SC_ESCAPED_STRING>
 389 {
 390   \0        complain_at (*loc, _("invalid null character"));
 391 }
 392
 393
 394   /*----------------------------.
 395   | Decode escaped characters.  |
 396   `----------------------------*/
 397
 398 <SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>
 399 {
 400   \\[0-7]{1,3} {
 401     unsigned long int c = strtoul (yytext + 1, NULL, 8);
 402     if (UCHAR_MAX < c)
 403       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
 404     else if (! c)
 405       complain_at (*loc, _("invalid null character: %s"), quote (yytext));
 406     else
 407       obstack_1grow (&obstack_for_string, c);
 408   }
 409
 410   \\x[0-9abcdefABCDEF]+ {
 411     verify (UCHAR_MAX < ULONG_MAX);
 412     unsigned long int c = strtoul (yytext + 2, NULL, 16);
 413     if (UCHAR_MAX < c)
 414       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
 415     else if (! c)
 416       complain_at (*loc, _("invalid null character: %s"), quote (yytext));
 417     else
 418       obstack_1grow (&obstack_for_string, c);
 419   }
 420
 421   \\a   obstack_1grow (&obstack_for_string, '\a');
 422   \\b   obstack_1grow (&obstack_for_string, '\b');
 423   \\f   obstack_1grow (&obstack_for_string, '\f');
 424   \\n   obstack_1grow (&obstack_for_string, '\n');
 425   \\r   obstack_1grow (&obstack_for_string, '\r');
 426   \\t   obstack_1grow (&obstack_for_string, '\t');
 427   \\v   obstack_1grow (&obstack_for_string, '\v');
 428
 429   /* \\[\"\'?\\] would be shorter, but it confuses xgettext.  */
 430   \\("\""|"'"|"?"|"\\")  obstack_1grow (&obstack_for_string, yytext[1]);
 431
 432   \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
 433     int c = convert_ucn_to_byte (yytext);
 434     if (c < 0)
 435       complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
 436     else if (! c)
 437       complain_at (*loc, _("invalid null character: %s"), quote (yytext));
 438     else
 439       obstack_1grow (&obstack_for_string, c);
 440   }
 441   \\(.|\n)      {
 442     complain_at (*loc, _("unrecognized escape sequence: %s"), quote (yytext));
 443     STRING_GROW;
 444   }
 445 }
 446
 447   /*--------------------------------------------.
 448   | Scanning user-code characters and strings.  |
 449   `--------------------------------------------*/
 450
 451 <SC_CHARACTER,SC_STRING>
 452 {
 453   {splice}|\\{splice}[^\n\[\]]  STRING_GROW;
 454 }
 455
 456 <SC_CHARACTER>
 457 {
 458   "'"           STRING_GROW; BEGIN context_state;
 459   \n            unexpected_newline (token_start, "'"); BEGIN context_state;
 460   <<EOF>>       unexpected_eof (token_start, "'"); BEGIN context_state;
 461 }
 462
 463 <SC_STRING>
 464 {
 465   "\""          STRING_GROW; BEGIN context_state;
 466   \n            unexpected_newline (token_start, "\""); BEGIN context_state;
 467   <<EOF>>       unexpected_eof (token_start, "\""); BEGIN context_state;
 468 }
 469
 470
 471   /*---------------------------------------------------.
 472   | Strings, comments etc. can be found in user code.  |
 473   `---------------------------------------------------*/
 474
 475 <SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>
 476 {
 477   "'" {
 478     STRING_GROW;
 479     context_state = YY_START;
 480     token_start = loc->start;
 481     BEGIN SC_CHARACTER;
 482   }
 483   "\"" {
 484     STRING_GROW;
 485     context_state = YY_START;
 486     token_start = loc->start;
 487     BEGIN SC_STRING;
 488   }
 489   "/"{splice}"*" {
 490     STRING_GROW;
 491     context_state = YY_START;
 492     token_start = loc->start;
 493     BEGIN SC_COMMENT;
 494   }
 495   "/"{splice}"/" {
 496     STRING_GROW;
 497     context_state = YY_START;
 498     BEGIN SC_LINE_COMMENT;
 499   }
 500 }
 501
 502
 503
 504   /*-----------------------------------------------------------.
 505   | Scanning some code in braces (actions). The initial "{" is |
 506   | already eaten.                                             |
 507   `-----------------------------------------------------------*/
 508
 509 <SC_BRACED_CODE>
 510 {
 511   "{"|"<"{splice}"%"  STRING_GROW; braces_level++;
 512   "%"{splice}">"      STRING_GROW; braces_level--;
 513   "}" {
 514     obstack_1grow (&obstack_for_string, '}');
 515
 516     --braces_level;
 517     if (braces_level < 0)
 518       {
 519         STRING_FINISH;
 520         loc->start = code_start;
 521         val->code = last_string;
 522         BEGIN INITIAL;
 523         return BRACED_CODE;
 524       }
 525   }
 526
 527   /* Tokenize `<<%' correctly (as `<<' `%') rather than incorrrectly
 528      (as `<' `<%').  */
 529   "<"{splice}"<"  STRING_GROW;
 530
 531   <<EOF>> {
 532     unexpected_eof (code_start, "}");
 533     STRING_FINISH;
 534     loc->start = code_start;
 535     val->code = last_string;
 536     BEGIN INITIAL;
 537     return BRACED_CODE;
 538   }
 539 }
 540
 541
 542   /*--------------------------------------------------------------.
 543   | Scanning some prologue: from "%{" (already scanned) to "%}".  |
 544   `--------------------------------------------------------------*/
 545
 546 <SC_PROLOGUE>
 547 {
 548   "%}" {
 549     STRING_FINISH;
 550     loc->start = code_start;
 551     val->chars = last_string;
 552     BEGIN INITIAL;
 553     return PROLOGUE;
 554   }
 555
 556   <<EOF>> {
 557     unexpected_eof (code_start, "%}");
 558     STRING_FINISH;
 559     loc->start = code_start;
 560     val->chars = last_string;
 561     BEGIN INITIAL;
 562     return PROLOGUE;
 563   }
 564 }
 565
 566
 567   /*---------------------------------------------------------------.
 568   | Scanning the epilogue (everything after the second "%%", which |
 569   | has already been eaten).                                       |
 570   `---------------------------------------------------------------*/
 571
 572 <SC_EPILOGUE>
 573 {
 574   <<EOF>> {
 575     STRING_FINISH;
 576     loc->start = code_start;
 577     val->chars = last_string;
 578     BEGIN INITIAL;
 579     return EPILOGUE;
 580   }
 581 }
 582
 583
 584   /*-----------------------------------------------------.
 585   | By default, grow the string obstack with the input.  |
 586   `-----------------------------------------------------*/
 587
 588 <SC_COMMENT,SC_LINE_COMMENT,SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE,SC_STRING,SC_CHARACTER,SC_ESCAPED_STRING,SC_ESCAPED_CHARACTER>.      |
 589 <SC_COMMENT,SC_LINE_COMMENT,SC_BRACED_CODE,SC_PROLOGUE,SC_EPILOGUE>\n   STRING_GROW;
 590
 591 %%
 592
 593 /* Read bytes from FP into buffer BUF of size SIZE.  Return the
 594    number of bytes read.  Remove '\r' from input, treating \r\n
 595    and isolated \r as \n.  */
 596
 597 static size_t
 598 no_cr_read (FILE *fp, char *buf, size_t size)
 599 {
 600   size_t bytes_read = fread (buf, 1, size, fp);
 601   if (bytes_read)
 602     {
 603       char *w = memchr (buf, '\r', bytes_read);
 604       if (w)
 605         {
 606           char const *r = ++w;
 607           char const *lim = buf + bytes_read;
 608
 609           for (;;)
 610             {
 611               /* Found an '\r'.  Treat it like '\n', but ignore any
 612                  '\n' that immediately follows.  */
 613               w[-1] = '\n';
 614               if (r == lim)
 615                 {
 616                   int ch = getc (fp);
 617                   if (ch != '\n' && ungetc (ch, fp) != ch)
 618                     break;
 619                 }
 620               else if (*r == '\n')
 621                 r++;
 622
 623               /* Copy until the next '\r'.  */
 624               do
 625                 {
 626                   if (r == lim)
 627                     return w - buf;
 628                 }
 629               while ((*w++ = *r++) != '\r');
 630             }
 631
 632           return w - buf;
 633         }
 634     }
 635
 636   return bytes_read;
 637 }
 638
 639
 640
 641 /*------------------------------------------------------.
 642 | Scan NUMBER for a base-BASE integer at location LOC.  |
 643 `------------------------------------------------------*/
 644
 645 static unsigned long int
 646 scan_integer (char const *number, int base, location loc)
 647 {
 648   verify (INT_MAX < ULONG_MAX);
 649   unsigned long int num = strtoul (number, NULL, base);
 650
 651   if (INT_MAX < num)
 652     {
 653       complain_at (loc, _("integer out of range: %s"), quote (number));
 654       num = INT_MAX;
 655     }
 656
 657   return num;
 658 }
 659
 660
 661 /*------------------------------------------------------------------.
 662 | Convert universal character name UCN to a single-byte character,  |
 663 | and return that character.  Return -1 if UCN does not correspond  |
 664 | to a single-byte character.                                       |
 665 `------------------------------------------------------------------*/
 666
 667 static int
 668 convert_ucn_to_byte (char const *ucn)
 669 {
 670   verify (UCHAR_MAX <= INT_MAX);
 671   unsigned long int code = strtoul (ucn + 2, NULL, 16);
 672
 673   /* FIXME: Currently we assume Unicode-compatible unibyte characters
 674      on ASCII hosts (i.e., Latin-1 on hosts with 8-bit bytes).  On
 675      non-ASCII hosts we support only the portable C character set.
 676      These limitations should be removed once we add support for
 677      multibyte characters.  */
 678
 679   if (UCHAR_MAX < code)
 680     return -1;
 681
 682 #if ! ('$' == 0x24 && '@' == 0x40 && '`' == 0x60 && '~' == 0x7e)
 683   {
 684     /* A non-ASCII host.  Use CODE to index into a table of the C
 685        basic execution character set, which is guaranteed to exist on
 686        all Standard C platforms.  This table also includes '$', '@',
 687        and '`', which are not in the basic execution character set but
 688        which are unibyte characters on all the platforms that we know
 689        about.  */
 690     static signed char const table[] =
 691       {
 692         '\0',   -1,   -1,   -1,   -1,   -1,   -1, '\a',
 693         '\b', '\t', '\n', '\v', '\f', '\r',   -1,   -1,
 694           -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
 695           -1,   -1,   -1,   -1,   -1,   -1,   -1,   -1,
 696          ' ',  '!',  '"',  '#',  '$',  '%',  '&', '\'',
 697          '(',  ')',  '*',  '+',  ',',  '-',  '.',  '/',
 698          '0',  '1',  '2',  '3',  '4',  '5',  '6',  '7',
 699          '8',  '9',  ':',  ';',  '<',  '=',  '>',  '?',
 700          '@',  'A',  'B',  'C',  'D',  'E',  'F',  'G',
 701          'H',  'I',  'J',  'K',  'L',  'M',  'N',  'O',
 702          'P',  'Q',  'R',  'S',  'T',  'U',  'V',  'W',
 703          'X',  'Y',  'Z',  '[', '\\',  ']',  '^',  '_',
 704          '`',  'a',  'b',  'c',  'd',  'e',  'f',  'g',
 705          'h',  'i',  'j',  'k',  'l',  'm',  'n',  'o',
 706          'p',  'q',  'r',  's',  't',  'u',  'v',  'w',
 707          'x',  'y',  'z',  '{',  '|',  '}',  '~'
 708       };
 709
 710     code = code < sizeof table ? table[code] : -1;
 711   }
 712 #endif
 713
 714   return code;
 715 }
 716
 717
 718 /*----------------------------------------------------------------.
 719 | Handle `#line INT "FILE"'.  ARGS has already skipped `#line '.  |
 720 `----------------------------------------------------------------*/
 721
 722 static void
 723 handle_syncline (char *args, location loc)
 724 {
 725   char *after_num;
 726   unsigned long int lineno = strtoul (args, &after_num, 10);
 727   char *file = strchr (after_num, '"') + 1;
 728   *strchr (file, '"') = '\0';
 729   if (INT_MAX <= lineno)
 730     {
 731       warn_at (loc, _("line number overflow"));
 732       lineno = INT_MAX;
 733     }
 734   current_file = uniqstr_new (file);
 735   boundary_set (&scanner_cursor, current_file, lineno, 1);
 736 }
 737
 738
 739 /*----------------------------------------------------------------.
 740 | For a token or comment starting at START, report message MSGID, |
 741 | which should say that an end marker was found before            |
 742 | the expected TOKEN_END.                                         |
 743 `----------------------------------------------------------------*/
 744
 745 static void
 746 unexpected_end (boundary start, char const *msgid, char const *token_end)
 747 {
 748   location loc;
 749   loc.start = start;
 750   loc.end = scanner_cursor;
 751   complain_at (loc, _(msgid), token_end);
 752 }
 753
 754
 755 /*------------------------------------------------------------------------.
 756 | Report an unexpected EOF in a token or comment starting at START.       |
 757 | An end of file was encountered and the expected TOKEN_END was missing.  |
 758 `------------------------------------------------------------------------*/
 759
 760 static void
 761 unexpected_eof (boundary start, char const *token_end)
 762 {
 763   unexpected_end (start, N_("missing `%s' at end of file"), token_end);
 764 }
 765
 766
 767 /*----------------------------------------.
 768 | Likewise, but for unexpected newlines.  |
 769 `----------------------------------------*/
 770
 771 static void
 772 unexpected_newline (boundary start, char const *token_end)
 773 {
 774   unexpected_end (start, N_("missing `%s' at end of line"), token_end);
 775 }
 776
 777
 778 /*-------------------------.
 779 | Initialize the scanner.  |
 780 `-------------------------*/
 781
 782 void
 783 gram_scanner_initialize (void)
 784 {
 785   obstack_init (&obstack_for_string);
 786 }
 787
 788
 789 /*-----------------------------------------------.
 790 | Free all the memory allocated to the scanner.  |
 791 `-----------------------------------------------*/
 792
 793 void
 794 gram_scanner_free (void)
 795 {
 796   obstack_free (&obstack_for_string, 0);
 797   /* Reclaim Flex's buffers.  */
 798   yylex_destroy ();
 799 }