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 * Large grammars
  15   Are now supported (large token numbers, large grammar size (= sum of
  16   the LHS and RHS lengths).
  17
  18 * The initial rule is explicit.
  19   Bison used to play hacks with the initial rule, which the user does
  20   not write.  It is now explicit, and visible in the reports and
  21   graphs as rule 0.
  22
  23 * Useless rules are actually removed.
  24   Before, Bison reported the useless rules, but, although not used,
  25   included them in the parsers.
  26
  27 * False `Token not used' report fixed.
  28   On a grammar such as
  29
  30            %token useless useful
  31            %%
  32            exp: '0' %prec useful;
  33
  34   where a token was used to set the precedence of the last rule,
  35   bison reported both `useful' and `useless' as useless tokens.
  36
  37 * Revert the C++ namespace changes introduced in 1.31, as they caused too
  38   many portability hassles.
  39
  40 * Items overflow
  41   Bison no longer dumps core when there are too many items, it just
  42   dies.
  43
  44 * Token end-of-file
  45   The token end of file may be specified by the user, in which case,
  46   the user symbol is used in the reports, the graphs, and the verbose
  47   error messages instead of `$', which remains being the defaults.
  48   For instance
  49      %token YYEOF 0
  50   or
  51      %token YYEOF 0 "end of file"
  52 \f
  53 Changes in version 1.31, 2002-01-14:
  54
  55 * Many Bug Fixes
  56
  57 * GNU Gettext and %expect
  58   GNU Gettext asserts 10 s/r conflicts, but there are 7.  Now that
  59   Bison dies on incorrect %expectations, we fear there will be
  60   too many bug reports for Gettext, so _for the time being_, %expect
  61   does not trigger an error when the input file is named `plural.y'.
  62
  63 * Use of alloca in parsers
  64   If YYSTACK_USE_ALLOCA is defined to 0, then the parsers will use
  65   malloc exclusively.  Since 1.29, but was not NEWS'ed.
  66
  67   alloca is used only when compiled with GCC, to avoid portability
  68   problems as on AIX.
  69
  70 * When the generated parser lacks debugging code, YYDEBUG is now 0
  71   (as POSIX requires) instead of being undefined.
  72
  73 * User Actions
  74   Bison has always permitted actions such as { $$ = $1 }: it adds the
  75   ending semicolon.  Now if in Yacc compatibility mode, the semicolon
  76   is no longer output: one has to write { $$ = $1; }.
  77
  78 * Better C++ compliance
  79   The output parsers try to respect C++ namespaces.
  80
  81 * Reduced Grammars
  82   Fixed bugs when reporting useless nonterminals.
  83
  84 * 64 bit hosts
  85   The parsers work properly on 64 bit hosts.
  86
  87 * Error messages
  88   Some calls to strerror resulted in scrambled or missing error messages.
  89
  90 * %expect
  91   When the number of shift/reduce conflicts is correct, don't issue
  92   any warning.
  93
  94 * The verbose report includes the rule line numbers.
  95
  96 * Rule line numbers are fixed in traces.
  97
  98 * Swedish translation
  99
 100 * Parse errors
 101   Verbose parse error messages from the parsers are better looking.
 102   Before: parse error: unexpected `'/'', expecting `"number"' or `'-'' or `'(''
 103      Now: parse error: unexpected '/', expecting "number" or '-' or '('
 104
 105 * Fixed parser memory leaks.
 106   When the generated parser was using malloc to extend its stacks, the
 107   previous allocations were not freed.
 108
 109 * Fixed verbose output file.
 110   Some newlines were missing.
 111   Some conflicts in state descriptions were missing.
 112
 113 * Fixed conflict report.
 114   Option -v was needed to get the result.
 115
 116 * %expect
 117   Was not used.
 118   Mismatches are errors, not warnings.
 119
 120 * Fixed incorrect processing of some invalid input.
 121
 122 * Fixed CPP guards: 9foo.h uses BISON_9FOO_H instead of 9FOO_H.
 123
 124 * Fixed some typos in the documentation.
 125
 126 * %token MY_EOF 0 is supported.
 127   Before, MY_EOF was silently renumbered as 257.
 128
 129 * doc/refcard.tex is updated.
 130
 131 * %output, %file-prefix, %name-prefix.
 132   New.
 133
 134 * --output
 135   New, aliasing `--output-file'.
 136 \f
 137 Changes in version 1.30:
 138
 139 * `--defines' and `--graph' have now an optionnal argument which is the
 140   output file name. `-d' and `-g' do not change, they do not take any
 141   argument.
 142
 143 * `%source_extension' and `%header_extension' are removed, failed
 144   experiment.
 145
 146 * Portability fixes.
 147 \f
 148 Changes in version 1.29, 2001-09-07:
 149
 150 * The output file does not define const, as this caused problems when used
 151   with common autoconfiguration schemes.  If you still use ancient compilers
 152   that lack const, compile with the equivalent of the C compiler option
 153   `-Dconst='.  autoconf's AC_C_CONST macro provides one way to do this.
 154
 155 * Added `-g' and `--graph'.
 156
 157 * The Bison manual is now distributed under the terms of the GNU FDL.
 158
 159 * The input and the output files has automatically a similar extension.
 160
 161 * Russian translation added.
 162
 163 * NLS support updated; should hopefully be less troublesome.
 164
 165 * Added the old Bison reference card.
 166
 167 * Added `--locations' and `%locations'.
 168
 169 * Added `-S' and `--skeleton'.
 170
 171 * `%raw', `-r', `--raw' is disabled.
 172
 173 * Special characters are escaped when output.  This solves the problems
 174   of the #line lines with path names including backslashes.
 175
 176 * New directives.
 177   `%yacc', `%fixed_output_files', `%defines', `%no_parser', `%verbose',
 178   `%debug', `%source_extension' and `%header_extension'.
 179
 180 * @$
 181   Automatic location tracking.
 182 \f
 183 Changes in version 1.28, 1999-07-06:
 184
 185 * Should compile better now with K&R compilers.
 186
 187 * Added NLS.
 188
 189 * Fixed a problem with escaping the double quote character.
 190
 191 * There is now a FAQ.
 192 \f
 193 Changes in version 1.27:
 194
 195 * The make rule which prevented bison.simple from being created on
 196   some systems has been fixed.
 197 \f
 198 Changes in version 1.26:
 199
 200 * Bison now uses automake.
 201
 202 * New mailing lists: <bug-bison@gnu.org> and <help-bison@gnu.org>.
 203
 204 * Token numbers now start at 257 as previously documented, not 258.
 205
 206 * Bison honors the TMPDIR environment variable.
 207
 208 * A couple of buffer overruns have been fixed.
 209
 210 * Problems when closing files should now be reported.
 211
 212 * Generated parsers should now work even on operating systems which do
 213   not provide alloca().
 214 \f
 215 Changes in version 1.25, 1995-10-16:
 216
 217 * Errors in the input grammar are not fatal; Bison keeps reading
 218 the grammar file, and reports all the errors found in it.
 219
 220 * Tokens can now be specified as multiple-character strings: for
 221 example, you could use "<=" for a token which looks like <=, instead
 222 of chosing a name like LESSEQ.
 223
 224 * The %token_table declaration says to write a table of tokens (names
 225 and numbers) into the parser file.  The yylex function can use this
 226 table to recognize multiple-character string tokens, or for other
 227 purposes.
 228
 229 * The %no_lines declaration says not to generate any #line preprocessor
 230 directives in the parser file.
 231
 232 * The %raw declaration says to use internal Bison token numbers, not
 233 Yacc-compatible token numbers, when token names are defined as macros.
 234
 235 * The --no-parser option produces the parser tables without including
 236 the parser engine; a project can now use its own parser engine.
 237 The actions go into a separate file called NAME.act, in the form of
 238 a switch statement body.
 239 \f
 240 Changes in version 1.23:
 241
 242 The user can define YYPARSE_PARAM as the name of an argument to be
 243 passed into yyparse.  The argument should have type void *.  It should
 244 actually point to an object.  Grammar actions can access the variable
 245 by casting it to the proper pointer type.
 246
 247 Line numbers in output file corrected.
 248 \f
 249 Changes in version 1.22:
 250
 251 --help option added.
 252 \f
 253 Changes in version 1.20:
 254
 255 Output file does not redefine const for C++.
 256
 257 Local Variables:
 258 mode: outline
 259 End: