NEWS

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