NEWS

   1 Bison News
   2 ----------
   3
   4 Changes in version 1.49a:
   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 \f
  59 Changes in version 1.31, 2002-01-14:
  60
  61 * Many Bug Fixes
  62
  63 * GNU Gettext and %expect
  64   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
  65   Bison dies on incorrect %expectations, we fear there will be
  66   too many bug reports for Gettext, so _for the time being_, %expect
  67   does not trigger an error when the input file is named `plural.y'.
  68
  69 * Use of alloca in parsers
  70   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
  71   malloc exclusively.  Since 1.29, but was not NEWS'ed.
  72
  73   alloca is used only when compiled with GCC, to avoid portability
  74   problems as on AIX.
  75
  76 * When the generated parser lacks debugging code, YYDEBUG is now 0
  77   (as POSIX requires) instead of being undefined.
  78
  79 * User Actions
  80   Bison has always permitted actions such as { $$ = $1 }: it adds the
  81   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
  82   is no longer output: one has to write { $$ = $1; }.
  83
  84 * Better C++ compliance
  85   The output parsers try to respect C++ namespaces.
  86
  87 * Reduced Grammars
  88   Fixed bugs when reporting useless nonterminals.
  89
  90 * 64 bit hosts
  91   The parsers work properly on 64 bit hosts.
  92
  93 * Error messages
  94   Some calls to strerror resulted in scrambled or missing error messages.
  95
  96 * %expect
  97   When the number of shift/reduce conflicts is correct, don't issue
  98   any warning.
  99
 100 * The verbose report includes the rule line numbers.
 101
 102 * Rule line numbers are fixed in traces.
 103
 104 * Swedish translation
 105
 106 * Parse errors
 107   Verbose parse error messages from the parsers are better looking.
 108   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 109      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 110
 111 * Fixed parser memory leaks.
 112   When the generated parser was using malloc to extend its stacks, the
 113   previous allocations were not freed.
 114
 115 * Fixed verbose output file.
 116   Some newlines were missing.
 117   Some conflicts in state descriptions were missing.
 118
 119 * Fixed conflict report.
 120   Option -v was needed to get the result.
 121
 122 * %expect
 123   Was not used.
 124   Mismatches are errors, not warnings.
 125
 126 * Fixed incorrect processing of some invalid input.
 127
 128 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 129
 130 * Fixed some typos in the documentation.
 131
 132 * %token MY_EOF 0 is supported.
 133   Before, MY_EOF was silently renumbered as 257.
 134
 135 * doc/refcard.tex is updated.
 136
 137 * %output, %file-prefix, %name-prefix.
 138   New.
 139
 140 * --output
 141   New, aliasing `--output-file'.
 142 \f
 143 Changes in version 1.30:
 144
 145 * `--defines' and `--graph' have now an optionnal argument which is the
 146   output file name. `-d' and `-g' do not change, they do not take any
 147   argument.
 148
 149 * `%source_extension' and `%header_extension' are removed, failed
 150   experiment.
 151
 152 * Portability fixes.
 153 \f
 154 Changes in version 1.29, 2001-09-07:
 155
 156 * The output file does not define const, as this caused problems when used
 157   with common autoconfiguration schemes.  If you still use ancient compilers
 158   that lack const, compile with the equivalent of the C compiler option
 159   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 160
 161 * Added `-g' and `--graph'.
 162
 163 * The Bison manual is now distributed under the terms of the GNU FDL.
 164
 165 * The input and the output files has automatically a similar extension.
 166
 167 * Russian translation added.
 168
 169 * NLS support updated; should hopefully be less troublesome.
 170
 171 * Added the old Bison reference card.
 172
 173 * Added `--locations' and `%locations'.
 174
 175 * Added `-S' and `--skeleton'.
 176
 177 * `%raw', `-r', `--raw' is disabled.
 178
 179 * Special characters are escaped when output.  This solves the problems
 180   of the #line lines with path names including backslashes.
 181
 182 * New directives.
 183   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 184   `%debug', `%source_extension' and `%header_extension'.
 185
 186 * @$
 187   Automatic location tracking.
 188 \f
 189 Changes in version 1.28, 1999-07-06:
 190
 191 * Should compile better now with K&R compilers.
 192
 193 * Added NLS.
 194
 195 * Fixed a problem with escaping the double quote character.
 196
 197 * There is now a FAQ.
 198 \f
 199 Changes in version 1.27:
 200
 201 * The make rule which prevented bison.simple from being created on
 202   some systems has been fixed.
 203 \f
 204 Changes in version 1.26:
 205
 206 * Bison now uses automake.
 207
 208 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 209
 210 * Token numbers now start at 257 as previously documented, not 258.
 211
 212 * Bison honors the TMPDIR environment variable.
 213
 214 * A couple of buffer overruns have been fixed.
 215
 216 * Problems when closing files should now be reported.
 217
 218 * Generated parsers should now work even on operating systems which do
 219   not provide alloca().
 220 \f
 221 Changes in version 1.25, 1995-10-16:
 222
 223 * Errors in the input grammar are not fatal; Bison keeps reading
 224 the grammar file, and reports all the errors found in it.
 225
 226 * Tokens can now be specified as multiple-character strings: for
 227 example, you could use "<=" for a token which looks like <=, instead
 228 of chosing a name like LESSEQ.
 229
 230 * The %token_table declaration says to write a table of tokens (names
 231 and numbers) into the parser file.  The yylex function can use this
 232 table to recognize multiple-character string tokens, or for other
 233 purposes.
 234
 235 * The %no_lines declaration says not to generate any #line preprocessor
 236 directives in the parser file.
 237
 238 * The %raw declaration says to use internal Bison token numbers, not
 239 Yacc-compatible token numbers, when token names are defined as macros.
 240
 241 * The --no-parser option produces the parser tables without including
 242 the parser engine; a project can now use its own parser engine.
 243 The actions go into a separate file called NAME.act, in the form of
 244 a switch statement body.
 245 \f
 246 Changes in version 1.23:
 247
 248 The user can define YYPARSE_PARAM as the name of an argument to be
 249 passed into yyparse.  The argument should have type void *.  It should
 250 actually point to an object.  Grammar actions can access the variable
 251 by casting it to the proper pointer type.
 252
 253 Line numbers in output file corrected.
 254 \f
 255 Changes in version 1.22:
 256
 257 --help option added.
 258 \f
 259 Changes in version 1.20:
 260
 261 Output file does not redefine const for C++.
 262
 263 Local Variables:
 264 mode: outline
 265 End: