NEWS

   1 Bison News
   2 ----------
   3
   4 Changes in version 2.1b:
   5
   6 * %name-prefix changes the namespace name in C++ outputs.
   7
   8 * The C++ parsers export their token_type.
   9
  10 Changes in version 2.1a, 2006-02-13:
  11
  12 * Bison now allows multiple %union declarations, and concatenates
  13   their contents together.
  14
  15 * New warning: unused values
  16   Right-hand side symbols whose values are not used are reported,
  17   if the symbols have destructors.  For instance:
  18
  19      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
  20         | exp "+" exp
  21         ;
  22
  23   will trigger a warning about $$ and $5 in the first rule, and $3 in
  24   the second ($1 is copied to $$ by the default rule).  This example
  25   most likely contains three errors, and could be rewritten as:
  26
  27      exp: exp "?" exp ":" exp
  28             { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
  29         | exp "+" exp
  30             { $$ = $1 ? $1 : $3; if ($1) free ($3); }
  31         ;
  32
  33   However, if the original actions were really intended, memory leaks
  34   and all, the warnings can be suppressed by letting Bison believe the
  35   values are used, e.g.:
  36
  37      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
  38         | exp "+" exp         { $$ = $1; (void) $3; }
  39         ;
  40
  41   If there are mid-rule actions, the warning is issued if no action
  42   uses it.  The following triggers no warning: $1 and $3 are used.
  43
  44      exp: exp { push ($1); } '+' exp { push ($3); sum (); };
  45
  46   The warning is intended to help catching lost values and memory leaks.
  47   If a value is ignored, its associated memory typically is not reclaimed.
  48
  49 * %destructor vs. YYABORT, YYACCEPT, and YYERROR.
  50   Destructors are now called when user code invokes YYABORT, YYACCEPT,
  51   and YYERROR, for all objects on the stack, other than objects
  52   corresponding to the right-hand side of the current rule.
  53
  54 * %expect, %expect-rr
  55   Incorrect numbers of expected conflicts are now actual errors,
  56   instead of warnings.
  57
  58 * GLR, YACC parsers.
  59   The %parse-params are available in the destructors (and the
  60   experimental printers) as per the documentation.
  61
  62 * Bison now warns if it finds a stray `$' or `@' in an action.
  63
  64 * %require "VERSION"
  65   This specifies that the grammar file depends on features implemented
  66   in Bison version VERSION or higher.
  67
  68 * lalr1.cc: The token and value types are now class members.
  69   The tokens were defined as free form enums and cpp macros.  YYSTYPE
  70   was defined as a free form union.  They are now class members:
  71   tokens are enumerations of the `yy::parser::token' struct, and the
  72   semantic values have the `yy::parser::semantic_type' type.
  73
  74   If you do not want or can update to this scheme, the directive
  75   `%define "global_tokens_and_yystype" "1"' triggers the global
  76   definition of tokens and YYSTYPE.  This change is suitable both
  77   for previous releases of Bison, and this one.
  78
  79   If you wish to update, then make sure older version of Bison will
  80   fail using `%require "2.1a"'.
  81
  82 * DJGPP support added.
  83
  84 Changes in version 2.1, 2005-09-16:
  85
  86 * The C++ lalr1.cc skeleton supports %lex-param.
  87
  88 * Bison-generated parsers now support the translation of diagnostics like
  89   "syntax error" into languages other than English.  The default
  90   language is still English.  For details, please see the new
  91   Internationalization section of the Bison manual.  Software
  92   distributors should also see the new PACKAGING file.  Thanks to
  93   Bruno Haible for this new feature.
  94
  95 * Wording in the Bison-generated parsers has been changed slightly to
  96   simplify translation.  In particular, the message "memory exhausted"
  97   has replaced "parser stack overflow", as the old message was not
  98   always accurate for modern Bison-generated parsers.
  99
 100 * Destructors are now called when the parser aborts, for all symbols left
 101   behind on the stack.  Also, the start symbol is now destroyed after a
 102   successful parse.  In both cases, the behavior was formerly inconsistent.
 103
 104 * When generating verbose diagnostics, Bison-generated parsers no longer
 105   quote the literal strings associated with tokens.  For example, for
 106   a syntax error associated with '%token NUM "number"' they might
 107   print 'syntax error, unexpected number' instead of 'syntax error,
 108   unexpected "number"'.
 109
 110 Changes in version 2.0, 2004-12-25:
 111
 112 * Possibly-incompatible changes
 113
 114   - Bison-generated parsers no longer default to using the alloca function
 115     (when available) to extend the parser stack, due to widespread
 116     problems in unchecked stack-overflow detection.  You can "#define
 117     YYSTACK_USE_ALLOCA 1" to require the use of alloca, but please read
 118     the manual to determine safe values for YYMAXDEPTH in that case.
 119
 120   - Error token location.
 121     During error recovery, the location of the syntax error is updated
 122     to cover the whole sequence covered by the error token: it includes
 123     the shifted symbols thrown away during the first part of the error
 124     recovery, and the lookahead rejected during the second part.
 125
 126   - Semicolon changes:
 127     . Stray semicolons are no longer allowed at the start of a grammar.
 128     . Semicolons are now required after in-grammar declarations.
 129
 130   - Unescaped newlines are no longer allowed in character constants or
 131     string literals.  They were never portable, and GCC 3.4.0 has
 132     dropped support for them.  Better diagnostics are now generated if
 133     forget a closing quote.
 134
 135   - NUL bytes are no longer allowed in Bison string literals, unfortunately.
 136
 137 * New features
 138
 139   - GLR grammars now support locations.
 140
 141   - New directive: %initial-action.
 142     This directive allows the user to run arbitrary code (including
 143     initializing @$) from yyparse before parsing starts.
 144
 145   - A new directive "%expect-rr N" specifies the expected number of
 146     reduce/reduce conflicts in GLR parsers.
 147
 148   - %token numbers can now be hexadecimal integers, e.g., `%token FOO 0x12d'.
 149     This is a GNU extension.
 150
 151   - The option `--report=lookahead' was changed to `--report=look-ahead'.
 152     The old spelling still works, but is not documented and will be
 153     removed.
 154
 155   - Experimental %destructor support has been added to lalr1.cc.
 156
 157   - New configure option --disable-yacc, to disable installation of the
 158     yacc command and -ly library introduced in 1.875 for POSIX conformance.
 159
 160 * Bug fixes
 161
 162   - For now, %expect-count violations are now just warnings, not errors.
 163     This is for compatibility with Bison 1.75 and earlier (when there are
 164     reduce/reduce conflicts) and with Bison 1.30 and earlier (when there
 165     are too many or too few shift/reduce conflicts).  However, in future
 166     versions of Bison we plan to improve the %expect machinery so that
 167     these violations will become errors again.
 168
 169   - Within Bison itself, numbers (e.g., goto numbers) are no longer
 170     arbitrarily limited to 16-bit counts.
 171
 172   - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.
 173 \f
 174 Changes in version 1.875, 2003-01-01:
 175
 176 * The documentation license has been upgraded to version 1.2
 177   of the GNU Free Documentation License.
 178
 179 * syntax error processing
 180
 181   - In Yacc-style parsers YYLLOC_DEFAULT is now used to compute error
 182     locations too.  This fixes bugs in error-location computation.
 183
 184   - %destructor
 185     It is now possible to reclaim the memory associated to symbols
 186     discarded during error recovery.  This feature is still experimental.
 187
 188   - %error-verbose
 189     This new directive is preferred over YYERROR_VERBOSE.
 190
 191   - #defining yyerror to steal internal variables is discouraged.
 192     It is not guaranteed to work forever.
 193
 194 * POSIX conformance
 195
 196   - Semicolons are once again optional at the end of grammar rules.
 197     This reverts to the behavior of Bison 1.33 and earlier, and improves
 198     compatibility with Yacc.
 199
 200   - `parse error' -> `syntax error'
 201     Bison now uniformly uses the term `syntax error'; formerly, the code
 202     and manual sometimes used the term `parse error' instead.  POSIX
 203     requires `syntax error' in diagnostics, and it was thought better to
 204     be consistent.
 205
 206   - The documentation now emphasizes that yylex and yyerror must be
 207     declared before use.  C99 requires this.
 208
 209   - Bison now parses C99 lexical constructs like UCNs and
 210     backslash-newline within C escape sequences, as POSIX 1003.1-2001 requires.
 211
 212   - File names are properly escaped in C output.  E.g., foo\bar.y is
 213     output as "foo\\bar.y".
 214
 215   - Yacc command and library now available
 216     The Bison distribution now installs a `yacc' command, as POSIX requires.
 217     Also, Bison now installs a small library liby.a containing
 218     implementations of Yacc-compatible yyerror and main functions.
 219     This library is normally not useful, but POSIX requires it.
 220
 221   - Type clashes now generate warnings, not errors.
 222
 223   - If the user does not define YYSTYPE as a macro, Bison now declares it
 224     using typedef instead of defining it as a macro.
 225     For consistency, YYLTYPE is also declared instead of defined.
 226
 227 * Other compatibility issues
 228
 229   - %union directives can now have a tag before the `{', e.g., the
 230     directive `%union foo {...}' now generates the C code
 231     `typedef union foo { ... } YYSTYPE;'; this is for Yacc compatibility.
 232     The default union tag is `YYSTYPE', for compatibility with Solaris 9 Yacc.
 233     For consistency, YYLTYPE's struct tag is now `YYLTYPE' not `yyltype'.
 234     This is for compatibility with both Yacc and Bison 1.35.
 235
 236   - `;' is output before the terminating `}' of an action, for
 237     compatibility with Bison 1.35.
 238
 239   - Bison now uses a Yacc-style format for conflict reports, e.g.,
 240     `conflicts: 2 shift/reduce, 1 reduce/reduce'.
 241
 242   - `yystype' and `yyltype' are now obsolescent macros instead of being
 243     typedefs or tags; they are no longer documented and are planned to be
 244     withdrawn in a future release.
 245
 246 * GLR parser notes
 247
 248   - GLR and inline
 249     Users of Bison have to decide how they handle the portability of the
 250     C keyword `inline'.
 251
 252   - `parsing stack overflow...' -> `parser stack overflow'
 253     GLR parsers now report `parser stack overflow' as per the Bison manual.
 254
 255 * Bison now warns if it detects conflicting outputs to the same file,
 256   e.g., it generates a warning for `bison -d -o foo.h foo.y' since
 257   that command outputs both code and header to foo.h.
 258
 259 * #line in output files
 260   - --no-line works properly.
 261
 262 * Bison can no longer be built by a K&R C compiler; it requires C89 or
 263   later to be built.  This change originally took place a few versions
 264   ago, but nobody noticed until we recently asked someone to try
 265   building Bison with a K&R C compiler.
 266 \f
 267 Changes in version 1.75, 2002-10-14:
 268
 269 * Bison should now work on 64-bit hosts.
 270
 271 * Indonesian translation thanks to Tedi Heriyanto.
 272
 273 * GLR parsers
 274   Fix spurious parse errors.
 275
 276 * Pure parsers
 277   Some people redefine yyerror to steal yyparse' private variables.
 278   Reenable this trick until an official feature replaces it.
 279
 280 * Type Clashes
 281   In agreement with POSIX and with other Yaccs, leaving a default
 282   action is valid when $$ is untyped, and $1 typed:
 283
 284         untyped: ... typed;
 285
 286   but the converse remains an error:
 287
 288         typed: ... untyped;
 289
 290 * Values of mid-rule actions
 291   The following code:
 292
 293         foo: { ... } { $$ = $1; } ...
 294
 295   was incorrectly rejected: $1 is defined in the second mid-rule
 296   action, and is equal to the $$ of the first mid-rule action.
 297 \f
 298 Changes in version 1.50, 2002-10-04:
 299
 300 * GLR parsing
 301   The declaration
 302      %glr-parser
 303   causes Bison to produce a Generalized LR (GLR) parser, capable of handling
 304   almost any context-free grammar, ambiguous or not.  The new declarations
 305   %dprec and %merge on grammar rules allow parse-time resolution of
 306   ambiguities.  Contributed by Paul Hilfinger.
 307
 308   Unfortunately Bison 1.50 does not work properly on 64-bit hosts
 309   like the Alpha, so please stick to 32-bit hosts for now.
 310
 311 * Output Directory
 312   When not in Yacc compatibility mode, when the output file was not
 313   specified, running `bison foo/bar.y' created `foo/bar.c'.  It
 314   now creates `bar.c'.
 315
 316 * Undefined token
 317   The undefined token was systematically mapped to 2 which prevented
 318   the use of 2 by the user.  This is no longer the case.
 319
 320 * Unknown token numbers
 321   If yylex returned an out of range value, yyparse could die.  This is
 322   no longer the case.
 323
 324 * Error token
 325   According to POSIX, the error token must be 256.
 326   Bison extends this requirement by making it a preference: *if* the
 327   user specified that one of her tokens is numbered 256, then error
 328   will be mapped onto another number.
 329
 330 * Verbose error messages
 331   They no longer report `..., expecting error or...' for states where
 332   error recovery is possible.
 333
 334 * End token
 335   Defaults to `$end' instead of `$'.
 336
 337 * Error recovery now conforms to documentation and to POSIX
 338   When a Bison-generated parser encounters a syntax error, it now pops
 339   the stack until it finds a state that allows shifting the error
 340   token.  Formerly, it popped the stack until it found a state that
 341   allowed some non-error action other than a default reduction on the
 342   error token.  The new behavior has long been the documented behavior,
 343   and has long been required by POSIX.  For more details, please see
 344   Paul Eggert, "Reductions during Bison error handling" (2002-05-20)
 345   <http://lists.gnu.org/archive/html/bug-bison/2002-05/msg00038.html>.
 346
 347 * Traces
 348   Popped tokens and nonterminals are now reported.
 349
 350 * Larger grammars
 351   Larger grammars are now supported (larger token numbers, larger grammar
 352   size (= sum of the LHS and RHS lengths), larger LALR tables).
 353   Formerly, many of these numbers ran afoul of 16-bit limits;
 354   now these limits are 32 bits on most hosts.
 355
 356 * Explicit initial rule
 357   Bison used to play hacks with the initial rule, which the user does
 358   not write.  It is now explicit, and visible in the reports and
 359   graphs as rule 0.
 360
 361 * Useless rules
 362   Before, Bison reported the useless rules, but, although not used,
 363   included them in the parsers.  They are now actually removed.
 364
 365 * Useless rules, useless nonterminals
 366   They are now reported, as a warning, with their locations.
 367
 368 * Rules never reduced
 369   Rules that can never be reduced because of conflicts are now
 370   reported.
 371
 372 * Incorrect `Token not used'
 373   On a grammar such as
 374
 375            %token useless useful
 376            %%
 377            exp: '0' %prec useful;
 378
 379   where a token was used to set the precedence of the last rule,
 380   bison reported both `useful' and `useless' as useless tokens.
 381
 382 * Revert the C++ namespace changes introduced in 1.31
 383   as they caused too many portability hassles.
 384
 385 * Default locations
 386   By an accident of design, the default computation of @$ was
 387   performed after another default computation was performed: @$ = @1.
 388   The latter is now removed: YYLLOC_DEFAULT is fully responsible of
 389   the computation of @$.
 390
 391 * Token end-of-file
 392   The token end of file may be specified by the user, in which case,
 393   the user symbol is used in the reports, the graphs, and the verbose
 394   error messages instead of `$end', which remains being the default.
 395   For instance
 396      %token MYEOF 0
 397   or
 398      %token MYEOF 0 "end of file"
 399
 400 * Semantic parser
 401   This old option, which has been broken for ages, is removed.
 402
 403 * New translations
 404   Brazilian Portuguese, thanks to Alexandre Folle de Menezes.
 405   Croatian, thanks to Denis Lackovic.
 406
 407 * Incorrect token definitions
 408   When given `%token 'a' "A"', Bison used to output `#define 'a' 65'.
 409
 410 * Token definitions as enums
 411   Tokens are output both as the traditional #define's, and, provided
 412   the compiler supports ANSI C or is a C++ compiler, as enums.
 413   This lets debuggers display names instead of integers.
 414
 415 * Reports
 416   In addition to --verbose, bison supports --report=THINGS, which
 417   produces additional information:
 418   - itemset
 419     complete the core item sets with their closure
 420   - lookahead [changed to `look-ahead' in 1.875e and later]
 421     explicitly associate look-ahead tokens to items
 422   - solved
 423     describe shift/reduce conflicts solving.
 424     Bison used to systematically output this information on top of
 425     the report.  Solved conflicts are now attached to their states.
 426
 427 * Type clashes
 428   Previous versions don't complain when there is a type clash on
 429   the default action if the rule has a mid-rule action, such as in:
 430
 431       %type <foo> bar
 432       %%
 433       bar: '0' {} '0';
 434
 435   This is fixed.
 436
 437 * GNU M4 is now required when using Bison.
 438 \f
 439 Changes in version 1.35, 2002-03-25:
 440
 441 * C Skeleton
 442   Some projects use Bison's C parser with C++ compilers, and define
 443   YYSTYPE as a class.  The recent adjustment of C parsers for data
 444   alignment and 64 bit architectures made this impossible.
 445
 446   Because for the time being no real solution for C++ parser
 447   generation exists, kludges were implemented in the parser to
 448   maintain this use.  In the future, when Bison has C++ parsers, this
 449   kludge will be disabled.
 450
 451   This kludge also addresses some C++ problems when the stack was
 452   extended.
 453 \f
 454 Changes in version 1.34, 2002-03-12:
 455
 456 * File name clashes are detected
 457   $ bison foo.y -d -o foo.x
 458   fatal error: header and parser would both be named `foo.x'
 459
 460 * A missing `;' at the end of a rule triggers a warning
 461   In accordance with POSIX, and in agreement with other
 462   Yacc implementations, Bison will mandate this semicolon in the near
 463   future.  This eases the implementation of a Bison parser of Bison
 464   grammars by making this grammar LALR(1) instead of LR(2).  To
 465   facilitate the transition, this release introduces a warning.
 466
 467 * Revert the C++ namespace changes introduced in 1.31, as they caused too
 468   many portability hassles.
 469
 470 * DJGPP support added.
 471
 472 * Fix test suite portability problems.
 473 \f
 474 Changes in version 1.33, 2002-02-07:
 475
 476 * Fix C++ issues
 477   Groff could not be compiled for the definition of size_t was lacking
 478   under some conditions.
 479
 480 * Catch invalid @n
 481   As is done with $n.
 482 \f
 483 Changes in version 1.32, 2002-01-23:
 484
 485 * Fix Yacc output file names
 486
 487 * Portability fixes
 488
 489 * Italian, Dutch translations
 490 \f
 491 Changes in version 1.31, 2002-01-14:
 492
 493 * Many Bug Fixes
 494
 495 * GNU Gettext and %expect
 496   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
 497   Bison dies on incorrect %expectations, we fear there will be
 498   too many bug reports for Gettext, so _for the time being_, %expect
 499   does not trigger an error when the input file is named `plural.y'.
 500
 501 * Use of alloca in parsers
 502   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
 503   malloc exclusively.  Since 1.29, but was not NEWS'ed.
 504
 505   alloca is used only when compiled with GCC, to avoid portability
 506   problems as on AIX.
 507
 508 * yyparse now returns 2 if memory is exhausted; formerly it dumped core.
 509
 510 * When the generated parser lacks debugging code, YYDEBUG is now 0
 511   (as POSIX requires) instead of being undefined.
 512
 513 * User Actions
 514   Bison has always permitted actions such as { $$ = $1 }: it adds the
 515   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
 516   is no longer output: one has to write { $$ = $1; }.
 517
 518 * Better C++ compliance
 519   The output parsers try to respect C++ namespaces.
 520   [This turned out to be a failed experiment, and it was reverted later.]
 521
 522 * Reduced Grammars
 523   Fixed bugs when reporting useless nonterminals.
 524
 525 * 64 bit hosts
 526   The parsers work properly on 64 bit hosts.
 527
 528 * Error messages
 529   Some calls to strerror resulted in scrambled or missing error messages.
 530
 531 * %expect
 532   When the number of shift/reduce conflicts is correct, don't issue
 533   any warning.
 534
 535 * The verbose report includes the rule line numbers.
 536
 537 * Rule line numbers are fixed in traces.
 538
 539 * Swedish translation
 540
 541 * Parse errors
 542   Verbose parse error messages from the parsers are better looking.
 543   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 544      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 545
 546 * Fixed parser memory leaks.
 547   When the generated parser was using malloc to extend its stacks, the
 548   previous allocations were not freed.
 549
 550 * Fixed verbose output file.
 551   Some newlines were missing.
 552   Some conflicts in state descriptions were missing.
 553
 554 * Fixed conflict report.
 555   Option -v was needed to get the result.
 556
 557 * %expect
 558   Was not used.
 559   Mismatches are errors, not warnings.
 560
 561 * Fixed incorrect processing of some invalid input.
 562
 563 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 564
 565 * Fixed some typos in the documentation.
 566
 567 * %token MY_EOF 0 is supported.
 568   Before, MY_EOF was silently renumbered as 257.
 569
 570 * doc/refcard.tex is updated.
 571
 572 * %output, %file-prefix, %name-prefix.
 573   New.
 574
 575 * --output
 576   New, aliasing `--output-file'.
 577 \f
 578 Changes in version 1.30, 2001-10-26:
 579
 580 * `--defines' and `--graph' have now an optional argument which is the
 581   output file name. `-d' and `-g' do not change; they do not take any
 582   argument.
 583
 584 * `%source_extension' and `%header_extension' are removed, failed
 585   experiment.
 586
 587 * Portability fixes.
 588 \f
 589 Changes in version 1.29, 2001-09-07:
 590
 591 * The output file does not define const, as this caused problems when used
 592   with common autoconfiguration schemes.  If you still use ancient compilers
 593   that lack const, compile with the equivalent of the C compiler option
 594   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 595
 596 * Added `-g' and `--graph'.
 597
 598 * The Bison manual is now distributed under the terms of the GNU FDL.
 599
 600 * The input and the output files has automatically a similar extension.
 601
 602 * Russian translation added.
 603
 604 * NLS support updated; should hopefully be less troublesome.
 605
 606 * Added the old Bison reference card.
 607
 608 * Added `--locations' and `%locations'.
 609
 610 * Added `-S' and `--skeleton'.
 611
 612 * `%raw', `-r', `--raw' is disabled.
 613
 614 * Special characters are escaped when output.  This solves the problems
 615   of the #line lines with path names including backslashes.
 616
 617 * New directives.
 618   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 619   `%debug', `%source_extension' and `%header_extension'.
 620
 621 * @$
 622   Automatic location tracking.
 623 \f
 624 Changes in version 1.28, 1999-07-06:
 625
 626 * Should compile better now with K&R compilers.
 627
 628 * Added NLS.
 629
 630 * Fixed a problem with escaping the double quote character.
 631
 632 * There is now a FAQ.
 633 \f
 634 Changes in version 1.27:
 635
 636 * The make rule which prevented bison.simple from being created on
 637   some systems has been fixed.
 638 \f
 639 Changes in version 1.26:
 640
 641 * Bison now uses automake.
 642
 643 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 644
 645 * Token numbers now start at 257 as previously documented, not 258.
 646
 647 * Bison honors the TMPDIR environment variable.
 648
 649 * A couple of buffer overruns have been fixed.
 650
 651 * Problems when closing files should now be reported.
 652
 653 * Generated parsers should now work even on operating systems which do
 654   not provide alloca().
 655 \f
 656 Changes in version 1.25, 1995-10-16:
 657
 658 * Errors in the input grammar are not fatal; Bison keeps reading
 659 the grammar file, and reports all the errors found in it.
 660
 661 * Tokens can now be specified as multiple-character strings: for
 662 example, you could use "<=" for a token which looks like <=, instead
 663 of chosing a name like LESSEQ.
 664
 665 * The %token_table declaration says to write a table of tokens (names
 666 and numbers) into the parser file.  The yylex function can use this
 667 table to recognize multiple-character string tokens, or for other
 668 purposes.
 669
 670 * The %no_lines declaration says not to generate any #line preprocessor
 671 directives in the parser file.
 672
 673 * The %raw declaration says to use internal Bison token numbers, not
 674 Yacc-compatible token numbers, when token names are defined as macros.
 675
 676 * The --no-parser option produces the parser tables without including
 677 the parser engine; a project can now use its own parser engine.
 678 The actions go into a separate file called NAME.act, in the form of
 679 a switch statement body.
 680 \f
 681 Changes in version 1.23:
 682
 683 The user can define YYPARSE_PARAM as the name of an argument to be
 684 passed into yyparse.  The argument should have type void *.  It should
 685 actually point to an object.  Grammar actions can access the variable
 686 by casting it to the proper pointer type.
 687
 688 Line numbers in output file corrected.
 689 \f
 690 Changes in version 1.22:
 691
 692 --help option added.
 693 \f
 694 Changes in version 1.20:
 695
 696 Output file does not redefine const for C++.
 697
 698 Local Variables:
 699 mode: outline
 700 End:
 701
 702 -----
 703
 704 Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
 705 2004, 2005, 2006 Free Software Foundation, Inc.
 706
 707 This file is part of Bison, the GNU Compiler Compiler.
 708
 709 Bison is free software; you can redistribute it and/or modify
 710 it under the terms of the GNU General Public License as published by
 711 the Free Software Foundation; either version 2, or (at your option)
 712 any later version.
 713
 714 Bison is distributed in the hope that it will be useful,
 715 but WITHOUT ANY WARRANTY; without even the implied warranty of
 716 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 717 GNU General Public License for more details.
 718
 719 You should have received a copy of the GNU General Public License
 720 along with autoconf; see the file COPYING.  If not, write to
 721 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 722 Boston, MA 02110-1301, USA.