NEWS

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