X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/05e25f2384b96708ffaaf01e77f432736bd99d83..afc4457605a784879fa57435bf45521ad7513771:/NEWS diff --git a/NEWS b/NEWS index c92eae5c..5df8b81a 100644 --- a/NEWS +++ b/NEWS @@ -2,6 +2,37 @@ GNU Bison NEWS * Noteworthy changes in release ?.? (????-??-??) [?] +** Bug fixes + +*** Errors in caret diagnostics + + On some platforms, some errors could result in endless diagnostics. + +*** Fixes of the -Werror option + + Options such as "-Werror -Wno-error=foo" were still turning "foo" + diagnostics into errors instead of warnings. This is fixed. + + Actually, for consistency with GCC, "-Wno-error=foo -Werror" now also + leaves "foo" diagnostics as warnings. Similarly, with "-Werror=foo + -Wno-error", "foo" diagnostics are now errors. + +*** GLR Predicates + + As demonstrated in the documentation, one can now leave spaces between + "%?" and its "{". + +*** Installation + + The yacc.1 man page is no longer installed if --disable-yacc was + specified. + +*** Fixes in the test suite + + Bugs and portability issues. + +* Noteworthy changes in release 3.0 (2013-07-25) [stable] + ** WARNING: Future backward-incompatibilities! Like other GNU packages, Bison will start using some of the C99 features @@ -23,6 +54,26 @@ GNU Bison NEWS Missing semicolons at the end of actions are no longer added (as announced in the release 2.5). +*** Use of YACC='bison -y' + + TL;DR: With Autoconf <= 2.69, pass -Wno-yacc to (AM_)YFLAGS if you use + Bison extensions. + + Traditional Yacc generates 'y.tab.c' whatever the name of the input file. + Therefore Makefiles written for Yacc expect 'y.tab.c' (and possibly + 'y.tab.h' and 'y.outout') to be generated from 'foo.y'. + + To this end, for ages, AC_PROG_YACC, Autoconf's macro to look for an + implementation of Yacc, was using Bison as 'bison -y'. While it does + ensure compatible output file names, it also enables warnings for + incompatibilities with POSIX Yacc. In other words, 'bison -y' triggers + warnings for Bison extensions. + + Autoconf 2.70+ fixes this incompatibility by using YACC='bison -o y.tab.c' + (which also generates 'y.tab.h' and 'y.output' when needed). + Alternatively, disable Yacc warnings by passing '-Wno-yacc' to your Yacc + flags (YFLAGS, or AM_YFLAGS with Automake). + ** Bug fixes *** The epilogue is no longer affected by internal #defines (glr.c) @@ -42,6 +93,8 @@ GNU Bison NEWS Changes in Bison 2.7 introduced a dependency on FILE and fprintf when locations are enabled. This is fixed. +*** Warnings about useless %pure-parser/%define api.pure are restored + ** Diagnostics reported by Bison Most of these features were contributed by Théophile Ranquet and Victor @@ -216,6 +269,11 @@ GNU Bison NEWS bar.y: error: shift/reduce conflicts: 1 found, 0 expected bar.y: error: reduce/reduce conflicts: 2 found, 0 expected +** Incompatibilities with POSIX Yacc + + The 'yacc' category is no longer part of '-Wall', enable it explicitly + with '-Wyacc'. + ** Additional yylex/yyparse arguments The new directive %param declares additional arguments to both yylex and @@ -231,6 +289,23 @@ GNU Bison NEWS %param {arg1_type *arg1} {arg2_type *arg2} +** Types of values for %define variables + + Bison used to make no difference between '%define foo bar' and '%define + foo "bar"'. The former is now called a 'keyword value', and the latter a + 'string value'. A third kind was added: 'code values', such as '%define + foo {bar}'. + + Keyword variables are used for fixed value sets, e.g., + + %define lr.type lalr + + Code variables are used for value in the target language, e.g., + + %define api.value.type {struct semantic_type} + + String variables are used remaining cases, e.g. file names. + ** Variable api.token.prefix The variable api.token.prefix changes the way tokens are identified in @@ -238,7 +313,7 @@ GNU Bison NEWS with identifiers in the target language. For instance %token FILE for ERROR - %define api.token.prefix "TOK_" + %define api.token.prefix {TOK_} %% start: FILE for ERROR; @@ -247,6 +322,79 @@ GNU Bison NEWS use these prefixed token names, although the grammar itself still uses the short names (as in the sample rule given above). +** Variable api.value.type + + This new %define variable supersedes the #define macro YYSTYPE. The use + of YYSTYPE is discouraged. In particular, #defining YYSTYPE *and* either + using %union or %defining api.value.type results in undefined behavior. + + Either define api.value.type, or use "%union": + + %union + { + int ival; + char *sval; + } + %token INT "integer" + %token STRING "string" + %printer { fprintf (yyo, "%d", $$); } + %destructor { free ($$); } + + /* In yylex(). */ + yylval.ival = 42; return INT; + yylval.sval = "42"; return STRING; + + The %define variable api.value.type supports both keyword and code values. + + The keyword value 'union' means that the user provides genuine types, not + union member names such as "ival" and "sval" above (WARNING: will fail if + -y/--yacc/%yacc is enabled). + + %define api.value.type union + %token INT "integer" + %token STRING "string" + %printer { fprintf (yyo, "%d", $$); } + %destructor { free ($$); } + + /* In yylex(). */ + yylval.INT = 42; return INT; + yylval.STRING = "42"; return STRING; + + The keyword value variant is somewhat equivalent, but for C++ special + provision is made to allow classes to be used (more about this below). + + %define api.value.type variant + %token INT "integer" + %token STRING "string" + + Code values (in braces) denote user defined types. This is where YYSTYPE + used to be used. + + %code requires + { + struct my_value + { + enum + { + is_int, is_string + } kind; + union + { + int ival; + char *sval; + } u; + }; + } + %define api.value.type {struct my_value} + %token INT "integer" + %token STRING "string" + %printer { fprintf (yyo, "%d", $$); } + %destructor { free ($$); } + + /* In yylex(). */ + yylval.u.ival = 42; return INT; + yylval.u.sval = "42"; return STRING; + ** Variable parse.error This variable controls the verbosity of error messages. The use of the @@ -279,11 +427,27 @@ GNU Bison NEWS It used to be an error only if used in non GLR mode, _and_ if there are reduce/reduce conflicts. -** Token numbering has changed to preserve the user-defined order +** Tokens are numbered in their order of appearance + + Contributed by Valentin Tolmer. - When declaring %token A B, the numbering for A is inferior to B. Up to now, - when declaring associativity at the same time, with %left (or %right, - %precedence, %nonassoc), B was inferior to A. + With '%token A B', A had a number less than the one of B. However, + precedence declarations used to generate a reversed order. This is now + fixed, and introducing tokens with any of %token, %left, %right, + %precedence, or %nonassoc yields the same result. + + When mixing declarations of tokens with a litteral character (e.g., 'a') + or with an identifier (e.g., B) in a precedence declaration, Bison + numbered the litteral characters first. For example + + %right A B 'c' 'd' + + would lead to the tokens declared in this order: 'c' 'd' A B. Again, the + input order is now preserved. + + These changes were made so that one can remove useless precedence and + associativity declarations (i.e., map %nonassoc, %left or %right to + %precedence, or to %token) and get exactly the same output. ** Useless precedence and associativity @@ -383,11 +547,13 @@ GNU Bison NEWS ** Java skeleton improvements - Contributed by Paolo Bonzini. - The constants for token names were moved to the Lexer interface. Also, it is possible to add code to the parser's constructors using "%code init" and "%define init_throws". + Contributed by Paolo Bonzini. + + The Java skeleton now supports push parsing. + Contributed by Dennis Heimbigner. ** C++ skeletons improvements @@ -456,6 +622,21 @@ GNU Bison NEWS ... } +*** C++ locations + + There are operator- and operator-= for 'location'. Negative line/column + increments can no longer underflow the resulting value. + +* Noteworthy changes in release 2.7.1 (2013-04-15) [stable] + +** Bug fixes + +*** Fix compiler attribute portability (yacc.c) + + With locations enabled, __attribute__ was used unprotected. + +*** Fix some compiler warnings (lalr1.cc) + * Noteworthy changes in release 2.7 (2012-12-12) [stable] ** Bug fixes @@ -2515,7 +2696,7 @@ along with this program. If not, see . LocalWords: Wprecedence Rassoul Wempty Paolo Bonzini parser's Michiel loc LocalWords: redeclaration sval fcaret reentrant XSLT xsl Wmaybe yyvsp Tedi LocalWords: pragmas noreturn untyped Rozenman unexpanded Wojciech Polak - LocalWords: Alexandre MERCHANTABILITY + LocalWords: Alexandre MERCHANTABILITY yytype Local Variables: mode: outline