X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/1eb0b146594c8b4a8e7aa06e4fcf275739d0900f..c76f5dfb03f6d2dbffe80e2d9438dfda74d84ebf:/NEWS diff --git a/NEWS b/NEWS index 72d73e13..f11844de 100644 --- a/NEWS +++ b/NEWS @@ -1,7 +1,99 @@ Bison News ---------- -* Changes in version ?.? (????-??-??): +* Changes in version 2.4.2 (????-??-??): + +** Some portability problems that resulted in failures and livelocks + in the test suite on some versions of at least Solaris, AIX, HP-UX, + RHEL4, and Tru64 have been fixed. As part of those fixes, fatal + Bison errors no longer cause M4 to report a broken pipe on the + affected platforms. + +** `%prec IDENTIFIER' requires IDENTIFIER to be defined separately. + + POSIX specifies that an error be reported for any identifier that does + not appear on the LHS of a grammar rule and that is not defined by + %token, %left, %right, or %nonassoc. Bison 2.3b and later lost this + error report for the case when an identifier appears only after a + %prec directive. It is now restored. However, for backward + compatibility with recent Bison releases, it is only a warning for + now. In Bison 2.5 and later, it will return to being an error. + +** Detection of GNU M4 1.4.6 or newer during configure is improved. + +** Warnings from gcc's -Wundef option about undefined YYENABLE_NLS, + YYLTYPE_IS_TRIVIAL, and __STRICT_ANSI__ in C/C++ parsers are now + avoided. + +** %code is now a permanent feature. + + A traditional Yacc prologue directive is written in the form: + + %{CODE%} + + To provide a more flexible alternative, Bison 2.3b introduced the + %code directive with the following forms for C/C++: + + %code {CODE} + %code requires {CODE} + %code provides {CODE} + %code top {CODE} + + These forms are now considered permanent features of Bison. See the + %code entries in the section "Bison Declaration Summary" in the Bison + manual for a summary of their functionality. See the section + "Prologue Alternatives" for a detailed discussion including the + advantages of %code over the traditional Yacc prologue directive. + + Bison's Java feature as a whole including its current usage of %code + is still considered experimental. + +** YYFAIL is deprecated and will eventually be removed. + + YYFAIL has existed for many years as an undocumented feature of + deterministic parsers in C generated by Bison. Previously, it was + documented for Bison's experimental Java parsers. YYFAIL is no longer + documented for Java parsers and is formally deprecated in both cases. + Users are strongly encouraged to migrate to YYERROR, which is + specified by POSIX. + + Like YYERROR, you can invoke YYFAIL from a semantic action in order to + induce a syntax error. The most obvious difference from YYERROR is + that YYFAIL will automatically invoke yyerror to report the syntax + error so that you don't have to. However, there are several other + subtle differences between YYERROR and YYFAIL, and YYFAIL suffers from + inherent flaws when %error-verbose or `#define YYERROR_VERBOSE' is + used. For a more detailed discussion, see: + + http://lists.gnu.org/archive/html/bison-patches/2009-12/msg00024.html + + The upcoming Bison 2.5 will remove YYFAIL from Java parsers, but + deterministic parsers in C will continue to implement it. However, + because YYFAIL is already flawed, it seems futile to try to make new + Bison features compatible with it. Thus, during parser generation, + Bison 2.5 will produce a warning whenever it discovers YYFAIL in a + rule action. In a later release, YYFAIL will be disabled for + %error-verbose and `#define YYERROR_VERBOSE'. Eventually, YYFAIL will + be removed altogether. + + There exists at least one case where Bison 2.5's YYFAIL warning will + be a false positive. Some projects add phony uses of YYFAIL and other + Bison-defined macros for the sole purpose of suppressing C + preprocessor warnings (from GCC cpp's -Wunused-macros, for example). + To avoid Bison's future warning, such YYFAIL uses can be moved to the + epilogue (that is, after the second `%%') in the Bison input file. In + this release (2.4.2), Bison already generates its own code to suppress + C preprocessor warnings for YYFAIL, so projects can remove their own + phony uses of YYFAIL if compatibility with Bison releases prior to + 2.4.2 is not necessary. + +** Internationalization. + + Fix a regression introduced in Bison 2.4: Under some circumstances, + message translations were not installed although supported by the + host system. + +* Changes in version 2.4.1 (2008-12-11): ** In the GLR defines file, unexpanded M4 macros in the yylval and yylloc declarations have been fixed. @@ -17,13 +109,12 @@ Bison News exp: exp "+" exp { $$ = $1 + $3; }; - This prevents the future support for languages that do not use `;' - as C/C++/Java do. Yet some grammars still depend on this `feature'. - Bison 2.4.1 restores the previous behavior in the case of C output - (specifically, when neither %language or %skeleton or equivalent - command-line options are used) to leave more time for grammars - depending on the old behavior to be adjusted. Future releases of - Bison will disable this feature. + Some grammars still depend on this `feature'. Bison 2.4.1 restores + the previous behavior in the case of C output (specifically, when + neither %language or %skeleton or equivalent command-line options + are used) to leave more time for grammars depending on the old + behavior to be adjusted. Future releases of Bison will disable this + feature. ** A few minor improvements to the Bison manual. @@ -1049,10 +1140,9 @@ End: ----- -Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, -2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. +Copyright (C) 1995-2010 Free Software Foundation, Inc. -This file is part of Bison, the GNU Compiler Compiler. +This file is part of Bison, the GNU Parser Generator. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by