X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/ea9a35c605c075c79da41bfeaaaa07b076bafc01..47db7ed1a855e7cc3022201085970c994b568513:/NEWS diff --git a/NEWS b/NEWS index 28654769..fa339aea 100644 --- a/NEWS +++ b/NEWS @@ -2,7 +2,21 @@ GNU Bison NEWS * Noteworthy changes in release ?.? (????-??-??) [?] -** Warnings about useless semantic types +** Incompatible changes + +*** Obsolete features + + Support for YYFAIL is removed, as announced since Bison 2.4.2. + +** Warnings + +*** Warning categories are now displayed in warnings + + For instance: + + foo.y:4.6: warning: type clash on default action: != [-Wother] + +*** Useless semantic types Bison now warns about useless (uninhabited) semantic types. Since semantic types are not declared to Bison (they are defined in the opaque @@ -19,7 +33,7 @@ GNU Bison NEWS 3.28-34: warning: type is used, but is not associated to any symbol 4.28-34: warning: type is used, but is not associated to any symbol -** Warnings about undeclared symbols +*** Undeclared symbols Bison used to raise an error for %printer and %destructor directives for undefined symbols. @@ -31,7 +45,7 @@ GNU Bison NEWS This is now only a warning. -** Warnings about useless destructors or printers +*** Useless destructors or printers Bison now warns about useless destructors or printers. In the following example, the printer for , and the destructor for are @@ -109,37 +123,56 @@ GNU Bison NEWS YYERROR) if the expression evaluates to 0, and are evaluated immediately in GLR parsers, rather than being deferred. The result is that they allow the programmer to prune possible parses based on the values of - runtime expressions. + run-time expressions. * Noteworthy changes in release ?.? (????-??-??) [?] + +* Noteworthy changes in release 2.6 (2012-07-19) [stable] + ** Future changes: - 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. + The next major release of Bison will drop support for the following + deprecated features. Please report disagreements to bug-bison@gnu.org. -** The generated header is included (yacc.c) +*** K&C parsers + + 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. + +*** 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 @@ -154,6 +187,80 @@ 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: @@ -191,10 +298,10 @@ GNU Bison NEWS The header files such as "parser.hh", "location.hh", etc. used a constant name for preprocessor guards, for instance: - #ifndef BISON_LOCATION_HH - # define BISON_LOCATION_HH - ... - #endif // !BISON_LOCATION_HH + #ifndef BISON_LOCATION_HH + # define BISON_LOCATION_HH + ... + #endif // !BISON_LOCATION_HH The inclusion guard is now computed from "PREFIX/FILE-NAME", where lower case characters are converted to upper case, and series of @@ -202,10 +309,10 @@ GNU Bison NEWS With "bison -o lang++/parser.cc", "location.hh" would now include: - #ifndef YY_LANG_LOCATION_HH - # define YY_LANG_LOCATION_HH - ... - #endif // !YY_LANG_LOCATION_HH + #ifndef YY_LANG_LOCATION_HH + # define YY_LANG_LOCATION_HH + ... + #endif // !YY_LANG_LOCATION_HH *** C++ locations: @@ -436,33 +543,33 @@ GNU Bison NEWS to use it. If, for instance, your location structure has "first" and "last" members, instead of - # define YYLLOC_DEFAULT(Current, Rhs, N) \ - do \ - if (N) \ - { \ - (Current).first = (Rhs)[1].location.first; \ - (Current).last = (Rhs)[N].location.last; \ - } \ - else \ - { \ - (Current).first = (Current).last = (Rhs)[0].location.last; \ - } \ - while (false) + # define YYLLOC_DEFAULT(Current, Rhs, N) \ + do \ + if (N) \ + { \ + (Current).first = (Rhs)[1].location.first; \ + (Current).last = (Rhs)[N].location.last; \ + } \ + else \ + { \ + (Current).first = (Current).last = (Rhs)[0].location.last; \ + } \ + while (false) use: - # define YYLLOC_DEFAULT(Current, Rhs, N) \ - do \ - if (N) \ - { \ - (Current).first = YYRHSLOC (Rhs, 1).first; \ - (Current).last = YYRHSLOC (Rhs, N).last; \ - } \ - else \ - { \ - (Current).first = (Current).last = YYRHSLOC (Rhs, 0).last; \ - } \ - while (false) + # define YYLLOC_DEFAULT(Current, Rhs, N) \ + do \ + if (N) \ + { \ + (Current).first = YYRHSLOC (Rhs, 1).first; \ + (Current).last = YYRHSLOC (Rhs, N).last; \ + } \ + else \ + { \ + (Current).first = (Current).last = YYRHSLOC (Rhs, 0).last; \ + } \ + while (false) ** YYLLOC_DEFAULT in C++: @@ -1322,7 +1429,7 @@ 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. @@ -1462,9 +1569,9 @@ GNU Bison NEWS ** Incorrect "Token not used" On a grammar such as - %token useless useful - %% - exp: '0' %prec useful; + %token useless useful + %% + exp: '0' %prec useful; where a token was used to set the precedence of the last rule, bison reported both "useful" and "useless" as useless tokens. @@ -1483,9 +1590,9 @@ GNU Bison NEWS the user symbol is used in the reports, the graphs, and the verbose error messages instead of "$end", which remains being the default. For instance - %token MYEOF 0 + %token MYEOF 0 or - %token MYEOF 0 "end of file" + %token MYEOF 0 "end of file" ** Semantic parser This old option, which has been broken for ages, is removed. @@ -1521,9 +1628,9 @@ GNU Bison NEWS Previous versions don't complain when there is a type clash on the default action if the rule has a mid-rule action, such as in: - %type bar - %% - bar: '0' {} '0'; + %type bar + %% + bar: '0' {} '0'; This is fixed. @@ -1820,9 +1927,12 @@ 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 Wother nterm arg init + LocalWords: TOK Local Variables: mode: outline