X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/18ad57b384e164c337e735df2f0ed0fe3c51fbf5..d35d6dd2cd153a88dd903d85882a9c190c5e607e:/NEWS diff --git a/NEWS b/NEWS index 72e4b6b3..b99290c9 100644 --- a/NEWS +++ b/NEWS @@ -2,33 +2,87 @@ GNU Bison NEWS * Noteworthy changes in release ?.? (????-??-??) [?] -** Future changes: + Bison no longer executes user-specified M4 code when processing a grammar. + +** Future Changes + + In addition to the removal of the features announced in Bison 2.6, the + next major release will remove the "Temporary hack for adding a semicolon + to the user action", as announced in the release 2.5. Instead of: + + exp: exp "+" exp { $$ = $1 + $3 }; + + write: + + exp: exp "+" exp { $$ = $1 + $3; }; + +** Bug fixes + +*** Type names are now properly escaped. + +*** glr.cc: set_debug_level and debug_level work as expected. + +*** Stray @ or $ in actions + + While Bison used to warn about stray $ or @ in action rules, it did not + for other actions such as printers, destructors, or initial actions. It + now does. + +** Type names in actions + + For consistency with rule actions, it is now possible to qualify $$ by a + type-name in destructors, printers, and initial actions. For instance: + + %printer { fprintf (yyo, "(%d, %f)", $$, $$); } <*> <>; + + will display two values for each typed and untyped symbol (provided + that YYSTYPE has both "ival" and "fval" fields). + +* Noteworthy changes in release 2.6 (2012-07-19) [stable] + +** Future Changes + + The next major release of Bison will drop support for the following + deprecated features. Please report disagreements to bug-bison@gnu.org. + +*** K&R C parsers - The next major release will drop support for generating parsers in K&R C, - and remove the definitions of yystype and yyltype (removal announced since - Bison 1.875). YYPARSE_PARAM and YYLEX_PARAM, which were deprecated in - favor of %parse-param and %lex-param (introduced in Bison 1.875 too), will - no longer be supported. + Support for generating parsers in K&R C will be removed. Parsers + generated for C support ISO C90, and are tested with ISO C99 and ISO C11 + compilers. -** The generated header is included (yacc.c) +*** Features deprecated since Bison 1.875 + + The definitions of yystype and yyltype will be removed; use YYSTYPE and + YYLTYPE. + + YYPARSE_PARAM and YYLEX_PARAM, deprecated in favor of %parse-param and + %lex-param, will no longer be supported. + + Support for the preprocessor symbol YYERROR_VERBOSE will be removed, use + %error-verbose. + +*** The generated header will be included (yacc.c) Instead of duplicating the content of the generated header (definition of - YYSTYPE, yyltype etc.), the generated parser now includes it, as was - already the case for GLR or C++ parsers. + YYSTYPE, yyparse declaration etc.), the generated parser will include it, + as is already the case for GLR or C++ parsers. This change is deferred + because existing versions of ylwrap (e.g., Automake 1.12.1) do not support + it. -** Headers (yacc.c, glr.c, glr.cc) +** Generated Parser Headers -*** Guards +*** Guards (yacc.c, glr.c, glr.cc) The generated headers are now guarded, as is already the case for C++ - parsers (lalr1.cc). For intance, with --defines=foo.h: + parsers (lalr1.cc). For instance, with --defines=foo.h: #ifndef YY_FOO_H # define YY_FOO_H ... #endif /* !YY_FOO_H */ -*** New declarations +*** New declarations (yacc.c, glr.c) The generated header now declares yydebug and yyparse. Both honor --name-prefix=bar_, and yield @@ -43,6 +97,80 @@ GNU Bison NEWS in order to facilitate the inclusion of several parser headers inside a single compilation unit. +*** Exported symbols in C++ + + The symbols YYTOKEN_TABLE and YYERROR_VERBOSE, which were defined in the + header, are removed, as they prevent the possibility of including several + generated headers from a single compilation unit. + +*** YYLSP_NEEDED + + For the same reasons, the undocumented and unused macro YYLSP_NEEDED is no + longer defined. + +** New %define variable: api.prefix + + Now that the generated headers are more complete and properly protected + against multiple inclusions, constant names, such as YYSTYPE are a + problem. While yyparse and others are properly renamed by %name-prefix, + YYSTYPE, YYDEBUG and others have never been affected by it. Because it + would introduce backward compatibility issues in projects not expecting + YYSTYPE to be renamed, instead of changing the behavior of %name-prefix, + it is deprecated in favor of a new %define variable: api.prefix. + + The following examples compares both: + + %name-prefix "bar_" | %define api.prefix "bar_" + %token FOO %token FOO + %union { int ival; } %union { int ival; } + %% %% + exp: 'a'; exp: 'a'; + + bison generates: + + #ifndef BAR_FOO_H #ifndef BAR_FOO_H + # define BAR_FOO_H # define BAR_FOO_H + + /* Enabling traces. */ /* Enabling traces. */ + # ifndef YYDEBUG | # ifndef BAR_DEBUG + > # if defined YYDEBUG + > # if YYDEBUG + > # define BAR_DEBUG 1 + > # else + > # define BAR_DEBUG 0 + > # endif + > # else + # define YYDEBUG 0 | # define BAR_DEBUG 0 + > # endif + # endif | # endif + + # if YYDEBUG | # if BAR_DEBUG + extern int bar_debug; extern int bar_debug; + # endif # endif + + /* Tokens. */ /* Tokens. */ + # ifndef YYTOKENTYPE | # ifndef BAR_TOKENTYPE + # define YYTOKENTYPE | # define BAR_TOKENTYPE + enum yytokentype { | enum bar_tokentype { + FOO = 258 FOO = 258 + }; }; + # endif # endif + + #if ! defined YYSTYPE \ | #if ! defined BAR_STYPE \ + && ! defined YYSTYPE_IS_DECLARED | && ! defined BAR_STYPE_IS_DECLARED + typedef union YYSTYPE | typedef union BAR_STYPE + { { + int ival; int ival; + } YYSTYPE; | } BAR_STYPE; + # define YYSTYPE_IS_DECLARED 1 | # define BAR_STYPE_IS_DECLARED 1 + #endif #endif + + extern YYSTYPE bar_lval; | extern BAR_STYPE bar_lval; + + int bar_parse (void); int bar_parse (void); + + #endif /* !BAR_FOO_H */ #endif /* !BAR_FOO_H */ + * Noteworthy changes in release 2.5.1 (2012-06-05) [stable] ** Future changes: @@ -1211,7 +1339,7 @@ GNU Bison NEWS - a single argument only can be added, - their types are weak (void *), - - this context is not passed to anciliary functions such as yyerror, + - this context is not passed to ancillary functions such as yyerror, - only yacc.c parsers support them. The new %parse-param/%lex-param directives provide a more precise control. @@ -1709,9 +1837,11 @@ along with this program. If not, see . LocalWords: struct yystype DJGPP lex param Haible NUM alloca YYSTACK NUL goto LocalWords: YYMAXDEPTH Unescaped UCNs YYLTYPE's yyltype typedefs inline Yaccs LocalWords: Heriyanto Reenable dprec Hilfinger Eggert MYEOF Folle Menezes EOF - LocalWords: Lackovic define's itemset Groff Gettext malloc NEWS'ed YYDEBUG + LocalWords: Lackovic define's itemset Groff Gettext malloc NEWS'ed YYDEBUG YY LocalWords: namespaces strerror const autoconfiguration Dconst Autoconf's FDL - LocalWords: Automake TMPDIR LESSEQ + LocalWords: Automake TMPDIR LESSEQ ylwrap endif yydebug YYTOKEN YYLSP ival hh + LocalWords: extern YYTOKENTYPE TOKENTYPE yytokentype tokentype STYPE lval pdf + LocalWords: lang yyoutput dvi html ps POSIX lvalp llocp Local Variables: mode: outline