NEWS

   1 Bison News
   2 ----------
   3
   4 Changes in version 1.49b:
   5
   6 * Undefined token
   7   The undefined token was systematically mapped to 2 which prevented
   8   the use of 2 from the user.  This is no longer the case.
   9
  10 * Undefined token
  11   If yylex returned a code out of range, yyparse could die.  This is
  12   no longer the case.
  13
  14 * Error token
  15   According to POSIX, the error token should be numbered as 256.
  16   Bison extends this requirement by making it a preference: *if* the
  17   user specified that one of her tokens is numbered 256, then error
  18   will be mapped onto another number.
  19
  20 * Large grammars
  21   Are now supported (large token numbers, large grammar size (= sum of
  22   the LHS and RHS lengths), large LALR tables).
  23
  24 * The initial rule is explicit.
  25   Bison used to play hacks with the initial rule, which the user does
  26   not write.  It is now explicit, and visible in the reports and
  27   graphs as rule 0.
  28
  29 * Useless rules are actually removed.
  30   Before, Bison reported the useless rules, but, although not used,
  31   included them in the parsers.
  32
  33 * False `Token not used' report fixed.
  34   On a grammar such as
  35
  36            %token useless useful
  37            %%
  38            exp: '0' %prec useful;
  39
  40   where a token was used to set the precedence of the last rule,
  41   bison reported both `useful' and `useless' as useless tokens.
  42
  43 * Revert the C++ namespace changes introduced in 1.31, as they caused too
  44   many portability hassles.
  45
  46 * Default locations
  47   By an accident of design, the default computation of @$ was
  48   performed after another default computation was performed: @$ = @1.
  49   The latter is now removed: YYLLOC_DEFAULT is fully responsible of
  50   the computation of @$.
  51
  52 * Token end-of-file
  53   The token end of file may be specified by the user, in which case,
  54   the user symbol is used in the reports, the graphs, and the verbose
  55   error messages instead of `$', which remains being the defaults.
  56   For instance
  57      %token YYEOF 0
  58   or
  59      %token YYEOF 0 "end of file"
  60
  61 * Semantic parser
  62   This old option, which has been broken for ages, is removed.
  63
  64 * New tranlations
  65   Croatian, thanks to Denis Lackovic.
  66
  67 * Token definitions
  68   When fed with `%token 'a' "A"', Bison used to output `#define 'a' 65'.
  69
  70 \f
  71 Changes in version 1.35, 2002-03-25:
  72
  73 * C Skeleton
  74   Some projects use Bison's C parser with C++ compilers, and define
  75   YYSTYPE as a class.  The recent adjustment of C parsers for data
  76   alignment and 64 bit architectures made this impossible.
  77
  78   Because for the time being no real solution for C++ parser
  79   generation exists, kludges were implemented in the parser to
  80   maintain this use.  In the future, when Bison has C++ parsers, this
  81   kludge will be disabled.
  82
  83   This kludge also addresses some C++ problems when the stack was
  84   extended.
  85
  86 \f
  87 Changes in version 1.34, 2002-03-12:
  88
  89 * File name clashes are detected
  90   $ bison foo.y -d -o foo.x
  91   fatal error: header and parser would both be named `foo.x'
  92
  93 * A missing `;' at the end of a rule triggers a warning
  94   In accordance with POSIX, and in agreement with other
  95   Yacc implementations, Bison will mandate this semicolon in the near
  96   future.  This eases the implementation of a Bison parser of Bison
  97   grammars by making this grammar LALR(1) instead of LR(2).  To
  98   facilitate the transition, this release introduces a warning.
  99
 100 * Revert the C++ namespace changes introduced in 1.31, as they caused too
 101   many portability hassles.
 102
 103 * DJGPP support added.
 104
 105 * Fix test suite portability problems.
 106 \f
 107 Changes in version 1.33, 2002-02-07:
 108
 109 * Fix C++ issues
 110   Groff could not be compiled for the definition of size_t was lacking
 111   under some conditions.
 112
 113 * Catch invalid @n
 114   As is done with $n.
 115 \f
 116 Changes in version 1.32, 2002-01-23:
 117
 118 * Fix Yacc output file names
 119
 120 * Portability fixes
 121
 122 * Italian, Dutch translations
 123 \f
 124 Changes in version 1.31, 2002-01-14:
 125
 126 * Many Bug Fixes
 127
 128 * GNU Gettext and %expect
 129   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
 130   Bison dies on incorrect %expectations, we fear there will be
 131   too many bug reports for Gettext, so _for the time being_, %expect
 132   does not trigger an error when the input file is named `plural.y'.
 133
 134 * Use of alloca in parsers
 135   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
 136   malloc exclusively.  Since 1.29, but was not NEWS'ed.
 137
 138   alloca is used only when compiled with GCC, to avoid portability
 139   problems as on AIX.
 140
 141 * When the generated parser lacks debugging code, YYDEBUG is now 0
 142   (as POSIX requires) instead of being undefined.
 143
 144 * User Actions
 145   Bison has always permitted actions such as { $$ = $1 }: it adds the
 146   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
 147   is no longer output: one has to write { $$ = $1; }.
 148
 149 * Better C++ compliance
 150   The output parsers try to respect C++ namespaces.
 151   [This turned out to be a failed experiment, and it was reverted later.]
 152
 153 * Reduced Grammars
 154   Fixed bugs when reporting useless nonterminals.
 155
 156 * 64 bit hosts
 157   The parsers work properly on 64 bit hosts.
 158
 159 * Error messages
 160   Some calls to strerror resulted in scrambled or missing error messages.
 161
 162 * %expect
 163   When the number of shift/reduce conflicts is correct, don't issue
 164   any warning.
 165
 166 * The verbose report includes the rule line numbers.
 167
 168 * Rule line numbers are fixed in traces.
 169
 170 * Swedish translation
 171
 172 * Parse errors
 173   Verbose parse error messages from the parsers are better looking.
 174   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 175      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 176
 177 * Fixed parser memory leaks.
 178   When the generated parser was using malloc to extend its stacks, the
 179   previous allocations were not freed.
 180
 181 * Fixed verbose output file.
 182   Some newlines were missing.
 183   Some conflicts in state descriptions were missing.
 184
 185 * Fixed conflict report.
 186   Option -v was needed to get the result.
 187
 188 * %expect
 189   Was not used.
 190   Mismatches are errors, not warnings.
 191
 192 * Fixed incorrect processing of some invalid input.
 193
 194 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 195
 196 * Fixed some typos in the documentation.
 197
 198 * %token MY_EOF 0 is supported.
 199   Before, MY_EOF was silently renumbered as 257.
 200
 201 * doc/refcard.tex is updated.
 202
 203 * %output, %file-prefix, %name-prefix.
 204   New.
 205
 206 * --output
 207   New, aliasing `--output-file'.
 208 \f
 209 Changes in version 1.30, 2001-10-26:
 210
 211 * `--defines' and `--graph' have now an optionnal argument which is the
 212   output file name. `-d' and `-g' do not change, they do not take any
 213   argument.
 214
 215 * `%source_extension' and `%header_extension' are removed, failed
 216   experiment.
 217
 218 * Portability fixes.
 219 \f
 220 Changes in version 1.29, 2001-09-07:
 221
 222 * The output file does not define const, as this caused problems when used
 223   with common autoconfiguration schemes.  If you still use ancient compilers
 224   that lack const, compile with the equivalent of the C compiler option
 225   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 226
 227 * Added `-g' and `--graph'.
 228
 229 * The Bison manual is now distributed under the terms of the GNU FDL.
 230
 231 * The input and the output files has automatically a similar extension.
 232
 233 * Russian translation added.
 234
 235 * NLS support updated; should hopefully be less troublesome.
 236
 237 * Added the old Bison reference card.
 238
 239 * Added `--locations' and `%locations'.
 240
 241 * Added `-S' and `--skeleton'.
 242
 243 * `%raw', `-r', `--raw' is disabled.
 244
 245 * Special characters are escaped when output.  This solves the problems
 246   of the #line lines with path names including backslashes.
 247
 248 * New directives.
 249   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 250   `%debug', `%source_extension' and `%header_extension'.
 251
 252 * @$
 253   Automatic location tracking.
 254 \f
 255 Changes in version 1.28, 1999-07-06:
 256
 257 * Should compile better now with K&R compilers.
 258
 259 * Added NLS.
 260
 261 * Fixed a problem with escaping the double quote character.
 262
 263 * There is now a FAQ.
 264 \f
 265 Changes in version 1.27:
 266
 267 * The make rule which prevented bison.simple from being created on
 268   some systems has been fixed.
 269 \f
 270 Changes in version 1.26:
 271
 272 * Bison now uses automake.
 273
 274 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 275
 276 * Token numbers now start at 257 as previously documented, not 258.
 277
 278 * Bison honors the TMPDIR environment variable.
 279
 280 * A couple of buffer overruns have been fixed.
 281
 282 * Problems when closing files should now be reported.
 283
 284 * Generated parsers should now work even on operating systems which do
 285   not provide alloca().
 286 \f
 287 Changes in version 1.25, 1995-10-16:
 288
 289 * Errors in the input grammar are not fatal; Bison keeps reading
 290 the grammar file, and reports all the errors found in it.
 291
 292 * Tokens can now be specified as multiple-character strings: for
 293 example, you could use "<=" for a token which looks like <=, instead
 294 of chosing a name like LESSEQ.
 295
 296 * The %token_table declaration says to write a table of tokens (names
 297 and numbers) into the parser file.  The yylex function can use this
 298 table to recognize multiple-character string tokens, or for other
 299 purposes.
 300
 301 * The %no_lines declaration says not to generate any #line preprocessor
 302 directives in the parser file.
 303
 304 * The %raw declaration says to use internal Bison token numbers, not
 305 Yacc-compatible token numbers, when token names are defined as macros.
 306
 307 * The --no-parser option produces the parser tables without including
 308 the parser engine; a project can now use its own parser engine.
 309 The actions go into a separate file called NAME.act, in the form of
 310 a switch statement body.
 311 \f
 312 Changes in version 1.23:
 313
 314 The user can define YYPARSE_PARAM as the name of an argument to be
 315 passed into yyparse.  The argument should have type void *.  It should
 316 actually point to an object.  Grammar actions can access the variable
 317 by casting it to the proper pointer type.
 318
 319 Line numbers in output file corrected.
 320 \f
 321 Changes in version 1.22:
 322
 323 --help option added.
 324 \f
 325 Changes in version 1.20:
 326
 327 Output file does not redefine const for C++.
 328
 329 Local Variables:
 330 mode: outline
 331 End:
 332
 333 -----
 334
 335 Copyright (C) 2001, 2002 Free Software Foundation, Inc.
 336
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