NEWS

   1 Bison News
   2 ----------
   3
   4 Changes in version 2.3+:
   5
   6 * The option `--report=look-ahead' has been changed to `--report=lookahead'.
   7   The old spelling still works, but is not documented and may be removed
   8   in a future release.
   9
  10 Changes in version 2.3, 2006-06-05:
  11
  12 * GLR grammars should now use `YYRECOVERING ()' instead of `YYRECOVERING',
  13   for compatibility with LALR(1) grammars.
  14
  15 * It is now documented that any definition of YYSTYPE or YYLTYPE should
  16   be to a type name that does not contain parentheses or brackets.
  17
  18 Changes in version 2.2, 2006-05-19:
  19
  20 * The distribution terms for all Bison-generated parsers now permit
  21   using the parsers in nonfree programs.  Previously, this permission
  22   was granted only for Bison-generated LALR(1) parsers in C.
  23
  24 * %name-prefix changes the namespace name in C++ outputs.
  25
  26 * The C++ parsers export their token_type.
  27
  28 * Bison now allows multiple %union declarations, and concatenates
  29   their contents together.
  30
  31 * New warning: unused values
  32   Right-hand side symbols whose values are not used are reported,
  33   if the symbols have destructors.  For instance:
  34
  35      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
  36         | exp "+" exp
  37         ;
  38
  39   will trigger a warning about $$ and $5 in the first rule, and $3 in
  40   the second ($1 is copied to $$ by the default rule).  This example
  41   most likely contains three errors, and could be rewritten as:
  42
  43      exp: exp "?" exp ":" exp
  44             { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
  45         | exp "+" exp
  46             { $$ = $1 ? $1 : $3; if ($1) free ($3); }
  47         ;
  48
  49   However, if the original actions were really intended, memory leaks
  50   and all, the warnings can be suppressed by letting Bison believe the
  51   values are used, e.g.:
  52
  53      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
  54         | exp "+" exp         { $$ = $1; (void) $3; }
  55         ;
  56
  57   If there are mid-rule actions, the warning is issued if no action
  58   uses it.  The following triggers no warning: $1 and $3 are used.
  59
  60      exp: exp { push ($1); } '+' exp { push ($3); sum (); };
  61
  62   The warning is intended to help catching lost values and memory leaks.
  63   If a value is ignored, its associated memory typically is not reclaimed.
  64
  65 * %destructor vs. YYABORT, YYACCEPT, and YYERROR.
  66   Destructors are now called when user code invokes YYABORT, YYACCEPT,
  67   and YYERROR, for all objects on the stack, other than objects
  68   corresponding to the right-hand side of the current rule.
  69
  70 * %expect, %expect-rr
  71   Incorrect numbers of expected conflicts are now actual errors,
  72   instead of warnings.
  73
  74 * GLR, YACC parsers.
  75   The %parse-params are available in the destructors (and the
  76   experimental printers) as per the documentation.
  77
  78 * Bison now warns if it finds a stray `$' or `@' in an action.
  79
  80 * %require "VERSION"
  81   This specifies that the grammar file depends on features implemented
  82   in Bison version VERSION or higher.
  83
  84 * lalr1.cc: The token and value types are now class members.
  85   The tokens were defined as free form enums and cpp macros.  YYSTYPE
  86   was defined as a free form union.  They are now class members:
  87   tokens are enumerations of the `yy::parser::token' struct, and the
  88   semantic values have the `yy::parser::semantic_type' type.
  89
  90   If you do not want or can update to this scheme, the directive
  91   `%define "global_tokens_and_yystype" "1"' triggers the global
  92   definition of tokens and YYSTYPE.  This change is suitable both
  93   for previous releases of Bison, and this one.
  94
  95   If you wish to update, then make sure older version of Bison will
  96   fail using `%require "2.2"'.
  97
  98 * DJGPP support added.
  99 \f
 100 Changes in version 2.1, 2005-09-16:
 101
 102 * The C++ lalr1.cc skeleton supports %lex-param.
 103
 104 * Bison-generated parsers now support the translation of diagnostics like
 105   "syntax error" into languages other than English.  The default
 106   language is still English.  For details, please see the new
 107   Internationalization section of the Bison manual.  Software
 108   distributors should also see the new PACKAGING file.  Thanks to
 109   Bruno Haible for this new feature.
 110
 111 * Wording in the Bison-generated parsers has been changed slightly to
 112   simplify translation.  In particular, the message "memory exhausted"
 113   has replaced "parser stack overflow", as the old message was not
 114   always accurate for modern Bison-generated parsers.
 115
 116 * Destructors are now called when the parser aborts, for all symbols left
 117   behind on the stack.  Also, the start symbol is now destroyed after a
 118   successful parse.  In both cases, the behavior was formerly inconsistent.
 119
 120 * When generating verbose diagnostics, Bison-generated parsers no longer
 121   quote the literal strings associated with tokens.  For example, for
 122   a syntax error associated with '%token NUM "number"' they might
 123   print 'syntax error, unexpected number' instead of 'syntax error,
 124   unexpected "number"'.
 125 \f
 126 Changes in version 2.0, 2004-12-25:
 127
 128 * Possibly-incompatible changes
 129
 130   - Bison-generated parsers no longer default to using the alloca function
 131     (when available) to extend the parser stack, due to widespread
 132     problems in unchecked stack-overflow detection.  You can "#define
 133     YYSTACK_USE_ALLOCA 1" to require the use of alloca, but please read
 134     the manual to determine safe values for YYMAXDEPTH in that case.
 135
 136   - Error token location.
 137     During error recovery, the location of the syntax error is updated
 138     to cover the whole sequence covered by the error token: it includes
 139     the shifted symbols thrown away during the first part of the error
 140     recovery, and the lookahead rejected during the second part.
 141
 142   - Semicolon changes:
 143     . Stray semicolons are no longer allowed at the start of a grammar.
 144     . Semicolons are now required after in-grammar declarations.
 145
 146   - Unescaped newlines are no longer allowed in character constants or
 147     string literals.  They were never portable, and GCC 3.4.0 has
 148     dropped support for them.  Better diagnostics are now generated if
 149     forget a closing quote.
 150
 151   - NUL bytes are no longer allowed in Bison string literals, unfortunately.
 152
 153 * New features
 154
 155   - GLR grammars now support locations.
 156
 157   - New directive: %initial-action.
 158     This directive allows the user to run arbitrary code (including
 159     initializing @$) from yyparse before parsing starts.
 160
 161   - A new directive "%expect-rr N" specifies the expected number of
 162     reduce/reduce conflicts in GLR parsers.
 163
 164   - %token numbers can now be hexadecimal integers, e.g., `%token FOO 0x12d'.
 165     This is a GNU extension.
 166
 167   - The option `--report=lookahead' was changed to `--report=look-ahead'.
 168     [However, this was changed back after 2.3.]
 169
 170   - Experimental %destructor support has been added to lalr1.cc.
 171
 172   - New configure option --disable-yacc, to disable installation of the
 173     yacc command and -ly library introduced in 1.875 for POSIX conformance.
 174
 175 * Bug fixes
 176
 177   - For now, %expect-count violations are now just warnings, not errors.
 178     This is for compatibility with Bison 1.75 and earlier (when there are
 179     reduce/reduce conflicts) and with Bison 1.30 and earlier (when there
 180     are too many or too few shift/reduce conflicts).  However, in future
 181     versions of Bison we plan to improve the %expect machinery so that
 182     these violations will become errors again.
 183
 184   - Within Bison itself, numbers (e.g., goto numbers) are no longer
 185     arbitrarily limited to 16-bit counts.
 186
 187   - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.
 188 \f
 189 Changes in version 1.875, 2003-01-01:
 190
 191 * The documentation license has been upgraded to version 1.2
 192   of the GNU Free Documentation License.
 193
 194 * syntax error processing
 195
 196   - In Yacc-style parsers YYLLOC_DEFAULT is now used to compute error
 197     locations too.  This fixes bugs in error-location computation.
 198
 199   - %destructor
 200     It is now possible to reclaim the memory associated to symbols
 201     discarded during error recovery.  This feature is still experimental.
 202
 203   - %error-verbose
 204     This new directive is preferred over YYERROR_VERBOSE.
 205
 206   - #defining yyerror to steal internal variables is discouraged.
 207     It is not guaranteed to work forever.
 208
 209 * POSIX conformance
 210
 211   - Semicolons are once again optional at the end of grammar rules.
 212     This reverts to the behavior of Bison 1.33 and earlier, and improves
 213     compatibility with Yacc.
 214
 215   - `parse error' -> `syntax error'
 216     Bison now uniformly uses the term `syntax error'; formerly, the code
 217     and manual sometimes used the term `parse error' instead.  POSIX
 218     requires `syntax error' in diagnostics, and it was thought better to
 219     be consistent.
 220
 221   - The documentation now emphasizes that yylex and yyerror must be
 222     declared before use.  C99 requires this.
 223
 224   - Bison now parses C99 lexical constructs like UCNs and
 225     backslash-newline within C escape sequences, as POSIX 1003.1-2001 requires.
 226
 227   - File names are properly escaped in C output.  E.g., foo\bar.y is
 228     output as "foo\\bar.y".
 229
 230   - Yacc command and library now available
 231     The Bison distribution now installs a `yacc' command, as POSIX requires.
 232     Also, Bison now installs a small library liby.a containing
 233     implementations of Yacc-compatible yyerror and main functions.
 234     This library is normally not useful, but POSIX requires it.
 235
 236   - Type clashes now generate warnings, not errors.
 237
 238   - If the user does not define YYSTYPE as a macro, Bison now declares it
 239     using typedef instead of defining it as a macro.
 240     For consistency, YYLTYPE is also declared instead of defined.
 241
 242 * Other compatibility issues
 243
 244   - %union directives can now have a tag before the `{', e.g., the
 245     directive `%union foo {...}' now generates the C code
 246     `typedef union foo { ... } YYSTYPE;'; this is for Yacc compatibility.
 247     The default union tag is `YYSTYPE', for compatibility with Solaris 9 Yacc.
 248     For consistency, YYLTYPE's struct tag is now `YYLTYPE' not `yyltype'.
 249     This is for compatibility with both Yacc and Bison 1.35.
 250
 251   - `;' is output before the terminating `}' of an action, for
 252     compatibility with Bison 1.35.
 253
 254   - Bison now uses a Yacc-style format for conflict reports, e.g.,
 255     `conflicts: 2 shift/reduce, 1 reduce/reduce'.
 256
 257   - `yystype' and `yyltype' are now obsolescent macros instead of being
 258     typedefs or tags; they are no longer documented and are planned to be
 259     withdrawn in a future release.
 260
 261 * GLR parser notes
 262
 263   - GLR and inline
 264     Users of Bison have to decide how they handle the portability of the
 265     C keyword `inline'.
 266
 267   - `parsing stack overflow...' -> `parser stack overflow'
 268     GLR parsers now report `parser stack overflow' as per the Bison manual.
 269
 270 * Bison now warns if it detects conflicting outputs to the same file,
 271   e.g., it generates a warning for `bison -d -o foo.h foo.y' since
 272   that command outputs both code and header to foo.h.
 273
 274 * #line in output files
 275   - --no-line works properly.
 276
 277 * Bison can no longer be built by a K&R C compiler; it requires C89 or
 278   later to be built.  This change originally took place a few versions
 279   ago, but nobody noticed until we recently asked someone to try
 280   building Bison with a K&R C compiler.
 281 \f
 282 Changes in version 1.75, 2002-10-14:
 283
 284 * Bison should now work on 64-bit hosts.
 285
 286 * Indonesian translation thanks to Tedi Heriyanto.
 287
 288 * GLR parsers
 289   Fix spurious parse errors.
 290
 291 * Pure parsers
 292   Some people redefine yyerror to steal yyparse' private variables.
 293   Reenable this trick until an official feature replaces it.
 294
 295 * Type Clashes
 296   In agreement with POSIX and with other Yaccs, leaving a default
 297   action is valid when $$ is untyped, and $1 typed:
 298
 299         untyped: ... typed;
 300
 301   but the converse remains an error:
 302
 303         typed: ... untyped;
 304
 305 * Values of mid-rule actions
 306   The following code:
 307
 308         foo: { ... } { $$ = $1; } ...
 309
 310   was incorrectly rejected: $1 is defined in the second mid-rule
 311   action, and is equal to the $$ of the first mid-rule action.
 312 \f
 313 Changes in version 1.50, 2002-10-04:
 314
 315 * GLR parsing
 316   The declaration
 317      %glr-parser
 318   causes Bison to produce a Generalized LR (GLR) parser, capable of handling
 319   almost any context-free grammar, ambiguous or not.  The new declarations
 320   %dprec and %merge on grammar rules allow parse-time resolution of
 321   ambiguities.  Contributed by Paul Hilfinger.
 322
 323   Unfortunately Bison 1.50 does not work properly on 64-bit hosts
 324   like the Alpha, so please stick to 32-bit hosts for now.
 325
 326 * Output Directory
 327   When not in Yacc compatibility mode, when the output file was not
 328   specified, running `bison foo/bar.y' created `foo/bar.c'.  It
 329   now creates `bar.c'.
 330
 331 * Undefined token
 332   The undefined token was systematically mapped to 2 which prevented
 333   the use of 2 by the user.  This is no longer the case.
 334
 335 * Unknown token numbers
 336   If yylex returned an out of range value, yyparse could die.  This is
 337   no longer the case.
 338
 339 * Error token
 340   According to POSIX, the error token must be 256.
 341   Bison extends this requirement by making it a preference: *if* the
 342   user specified that one of her tokens is numbered 256, then error
 343   will be mapped onto another number.
 344
 345 * Verbose error messages
 346   They no longer report `..., expecting error or...' for states where
 347   error recovery is possible.
 348
 349 * End token
 350   Defaults to `$end' instead of `$'.
 351
 352 * Error recovery now conforms to documentation and to POSIX
 353   When a Bison-generated parser encounters a syntax error, it now pops
 354   the stack until it finds a state that allows shifting the error
 355   token.  Formerly, it popped the stack until it found a state that
 356   allowed some non-error action other than a default reduction on the
 357   error token.  The new behavior has long been the documented behavior,
 358   and has long been required by POSIX.  For more details, please see
 359   Paul Eggert, "Reductions during Bison error handling" (2002-05-20)
 360   <http://lists.gnu.org/archive/html/bug-bison/2002-05/msg00038.html>.
 361
 362 * Traces
 363   Popped tokens and nonterminals are now reported.
 364
 365 * Larger grammars
 366   Larger grammars are now supported (larger token numbers, larger grammar
 367   size (= sum of the LHS and RHS lengths), larger LALR tables).
 368   Formerly, many of these numbers ran afoul of 16-bit limits;
 369   now these limits are 32 bits on most hosts.
 370
 371 * Explicit initial rule
 372   Bison used to play hacks with the initial rule, which the user does
 373   not write.  It is now explicit, and visible in the reports and
 374   graphs as rule 0.
 375
 376 * Useless rules
 377   Before, Bison reported the useless rules, but, although not used,
 378   included them in the parsers.  They are now actually removed.
 379
 380 * Useless rules, useless nonterminals
 381   They are now reported, as a warning, with their locations.
 382
 383 * Rules never reduced
 384   Rules that can never be reduced because of conflicts are now
 385   reported.
 386
 387 * Incorrect `Token not used'
 388   On a grammar such as
 389
 390            %token useless useful
 391            %%
 392            exp: '0' %prec useful;
 393
 394   where a token was used to set the precedence of the last rule,
 395   bison reported both `useful' and `useless' as useless tokens.
 396
 397 * Revert the C++ namespace changes introduced in 1.31
 398   as they caused too many portability hassles.
 399
 400 * Default locations
 401   By an accident of design, the default computation of @$ was
 402   performed after another default computation was performed: @$ = @1.
 403   The latter is now removed: YYLLOC_DEFAULT is fully responsible of
 404   the computation of @$.
 405
 406 * Token end-of-file
 407   The token end of file may be specified by the user, in which case,
 408   the user symbol is used in the reports, the graphs, and the verbose
 409   error messages instead of `$end', which remains being the default.
 410   For instance
 411      %token MYEOF 0
 412   or
 413      %token MYEOF 0 "end of file"
 414
 415 * Semantic parser
 416   This old option, which has been broken for ages, is removed.
 417
 418 * New translations
 419   Brazilian Portuguese, thanks to Alexandre Folle de Menezes.
 420   Croatian, thanks to Denis Lackovic.
 421
 422 * Incorrect token definitions
 423   When given `%token 'a' "A"', Bison used to output `#define 'a' 65'.
 424
 425 * Token definitions as enums
 426   Tokens are output both as the traditional #define's, and, provided
 427   the compiler supports ANSI C or is a C++ compiler, as enums.
 428   This lets debuggers display names instead of integers.
 429
 430 * Reports
 431   In addition to --verbose, bison supports --report=THINGS, which
 432   produces additional information:
 433   - itemset
 434     complete the core item sets with their closure
 435   - lookahead [changed to `look-ahead' in 1.875e through 2.3, but changed back]
 436     explicitly associate lookahead tokens to items
 437   - solved
 438     describe shift/reduce conflicts solving.
 439     Bison used to systematically output this information on top of
 440     the report.  Solved conflicts are now attached to their states.
 441
 442 * Type clashes
 443   Previous versions don't complain when there is a type clash on
 444   the default action if the rule has a mid-rule action, such as in:
 445
 446       %type <foo> bar
 447       %%
 448       bar: '0' {} '0';
 449
 450   This is fixed.
 451
 452 * GNU M4 is now required when using Bison.
 453 \f
 454 Changes in version 1.35, 2002-03-25:
 455
 456 * C Skeleton
 457   Some projects use Bison's C parser with C++ compilers, and define
 458   YYSTYPE as a class.  The recent adjustment of C parsers for data
 459   alignment and 64 bit architectures made this impossible.
 460
 461   Because for the time being no real solution for C++ parser
 462   generation exists, kludges were implemented in the parser to
 463   maintain this use.  In the future, when Bison has C++ parsers, this
 464   kludge will be disabled.
 465
 466   This kludge also addresses some C++ problems when the stack was
 467   extended.
 468 \f
 469 Changes in version 1.34, 2002-03-12:
 470
 471 * File name clashes are detected
 472   $ bison foo.y -d -o foo.x
 473   fatal error: header and parser would both be named `foo.x'
 474
 475 * A missing `;' at the end of a rule triggers a warning
 476   In accordance with POSIX, and in agreement with other
 477   Yacc implementations, Bison will mandate this semicolon in the near
 478   future.  This eases the implementation of a Bison parser of Bison
 479   grammars by making this grammar LALR(1) instead of LR(2).  To
 480   facilitate the transition, this release introduces a warning.
 481
 482 * Revert the C++ namespace changes introduced in 1.31, as they caused too
 483   many portability hassles.
 484
 485 * DJGPP support added.
 486
 487 * Fix test suite portability problems.
 488 \f
 489 Changes in version 1.33, 2002-02-07:
 490
 491 * Fix C++ issues
 492   Groff could not be compiled for the definition of size_t was lacking
 493   under some conditions.
 494
 495 * Catch invalid @n
 496   As is done with $n.
 497 \f
 498 Changes in version 1.32, 2002-01-23:
 499
 500 * Fix Yacc output file names
 501
 502 * Portability fixes
 503
 504 * Italian, Dutch translations
 505 \f
 506 Changes in version 1.31, 2002-01-14:
 507
 508 * Many Bug Fixes
 509
 510 * GNU Gettext and %expect
 511   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
 512   Bison dies on incorrect %expectations, we fear there will be
 513   too many bug reports for Gettext, so _for the time being_, %expect
 514   does not trigger an error when the input file is named `plural.y'.
 515
 516 * Use of alloca in parsers
 517   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
 518   malloc exclusively.  Since 1.29, but was not NEWS'ed.
 519
 520   alloca is used only when compiled with GCC, to avoid portability
 521   problems as on AIX.
 522
 523 * yyparse now returns 2 if memory is exhausted; formerly it dumped core.
 524
 525 * When the generated parser lacks debugging code, YYDEBUG is now 0
 526   (as POSIX requires) instead of being undefined.
 527
 528 * User Actions
 529   Bison has always permitted actions such as { $$ = $1 }: it adds the
 530   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
 531   is no longer output: one has to write { $$ = $1; }.
 532
 533 * Better C++ compliance
 534   The output parsers try to respect C++ namespaces.
 535   [This turned out to be a failed experiment, and it was reverted later.]
 536
 537 * Reduced Grammars
 538   Fixed bugs when reporting useless nonterminals.
 539
 540 * 64 bit hosts
 541   The parsers work properly on 64 bit hosts.
 542
 543 * Error messages
 544   Some calls to strerror resulted in scrambled or missing error messages.
 545
 546 * %expect
 547   When the number of shift/reduce conflicts is correct, don't issue
 548   any warning.
 549
 550 * The verbose report includes the rule line numbers.
 551
 552 * Rule line numbers are fixed in traces.
 553
 554 * Swedish translation
 555
 556 * Parse errors
 557   Verbose parse error messages from the parsers are better looking.
 558   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 559      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 560
 561 * Fixed parser memory leaks.
 562   When the generated parser was using malloc to extend its stacks, the
 563   previous allocations were not freed.
 564
 565 * Fixed verbose output file.
 566   Some newlines were missing.
 567   Some conflicts in state descriptions were missing.
 568
 569 * Fixed conflict report.
 570   Option -v was needed to get the result.
 571
 572 * %expect
 573   Was not used.
 574   Mismatches are errors, not warnings.
 575
 576 * Fixed incorrect processing of some invalid input.
 577
 578 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 579
 580 * Fixed some typos in the documentation.
 581
 582 * %token MY_EOF 0 is supported.
 583   Before, MY_EOF was silently renumbered as 257.
 584
 585 * doc/refcard.tex is updated.
 586
 587 * %output, %file-prefix, %name-prefix.
 588   New.
 589
 590 * --output
 591   New, aliasing `--output-file'.
 592 \f
 593 Changes in version 1.30, 2001-10-26:
 594
 595 * `--defines' and `--graph' have now an optional argument which is the
 596   output file name. `-d' and `-g' do not change; they do not take any
 597   argument.
 598
 599 * `%source_extension' and `%header_extension' are removed, failed
 600   experiment.
 601
 602 * Portability fixes.
 603 \f
 604 Changes in version 1.29, 2001-09-07:
 605
 606 * The output file does not define const, as this caused problems when used
 607   with common autoconfiguration schemes.  If you still use ancient compilers
 608   that lack const, compile with the equivalent of the C compiler option
 609   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 610
 611 * Added `-g' and `--graph'.
 612
 613 * The Bison manual is now distributed under the terms of the GNU FDL.
 614
 615 * The input and the output files has automatically a similar extension.
 616
 617 * Russian translation added.
 618
 619 * NLS support updated; should hopefully be less troublesome.
 620
 621 * Added the old Bison reference card.
 622
 623 * Added `--locations' and `%locations'.
 624
 625 * Added `-S' and `--skeleton'.
 626
 627 * `%raw', `-r', `--raw' is disabled.
 628
 629 * Special characters are escaped when output.  This solves the problems
 630   of the #line lines with path names including backslashes.
 631
 632 * New directives.
 633   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 634   `%debug', `%source_extension' and `%header_extension'.
 635
 636 * @$
 637   Automatic location tracking.
 638 \f
 639 Changes in version 1.28, 1999-07-06:
 640
 641 * Should compile better now with K&R compilers.
 642
 643 * Added NLS.
 644
 645 * Fixed a problem with escaping the double quote character.
 646
 647 * There is now a FAQ.
 648 \f
 649 Changes in version 1.27:
 650
 651 * The make rule which prevented bison.simple from being created on
 652   some systems has been fixed.
 653 \f
 654 Changes in version 1.26:
 655
 656 * Bison now uses automake.
 657
 658 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 659
 660 * Token numbers now start at 257 as previously documented, not 258.
 661
 662 * Bison honors the TMPDIR environment variable.
 663
 664 * A couple of buffer overruns have been fixed.
 665
 666 * Problems when closing files should now be reported.
 667
 668 * Generated parsers should now work even on operating systems which do
 669   not provide alloca().
 670 \f
 671 Changes in version 1.25, 1995-10-16:
 672
 673 * Errors in the input grammar are not fatal; Bison keeps reading
 674 the grammar file, and reports all the errors found in it.
 675
 676 * Tokens can now be specified as multiple-character strings: for
 677 example, you could use "<=" for a token which looks like <=, instead
 678 of chosing a name like LESSEQ.
 679
 680 * The %token_table declaration says to write a table of tokens (names
 681 and numbers) into the parser file.  The yylex function can use this
 682 table to recognize multiple-character string tokens, or for other
 683 purposes.
 684
 685 * The %no_lines declaration says not to generate any #line preprocessor
 686 directives in the parser file.
 687
 688 * The %raw declaration says to use internal Bison token numbers, not
 689 Yacc-compatible token numbers, when token names are defined as macros.
 690
 691 * The --no-parser option produces the parser tables without including
 692 the parser engine; a project can now use its own parser engine.
 693 The actions go into a separate file called NAME.act, in the form of
 694 a switch statement body.
 695 \f
 696 Changes in version 1.23:
 697
 698 The user can define YYPARSE_PARAM as the name of an argument to be
 699 passed into yyparse.  The argument should have type void *.  It should
 700 actually point to an object.  Grammar actions can access the variable
 701 by casting it to the proper pointer type.
 702
 703 Line numbers in output file corrected.
 704 \f
 705 Changes in version 1.22:
 706
 707 --help option added.
 708 \f
 709 Changes in version 1.20:
 710
 711 Output file does not redefine const for C++.
 712
 713 Local Variables:
 714 mode: outline
 715 End:
 716
 717 -----
 718
 719 Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
 720 2004, 2005, 2006 Free Software Foundation, Inc.
 721
 722 This file is part of Bison, the GNU Compiler Compiler.
 723
 724 Bison is free software; you can redistribute it and/or modify
 725 it under the terms of the GNU General Public License as published by
 726 the Free Software Foundation; either version 2, or (at your option)
 727 any later version.
 728
 729 Bison is distributed in the hope that it will be useful,
 730 but WITHOUT ANY WARRANTY; without even the implied warranty of
 731 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 732 GNU General Public License for more details.
 733
 734 You should have received a copy of the GNU General Public License
 735 along with autoconf; see the file COPYING.  If not, write to
 736 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 737 Boston, MA 02110-1301, USA.