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