X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d87ea54cf6cc98d52356c138bd142d1b450bbc9a..c6b1772473d0a26faa22464df98718d0d0ae2e2e:/NEWS diff --git a/NEWS b/NEWS index bc66a4cb..c8cab5e0 100644 --- a/NEWS +++ b/NEWS @@ -13,18 +13,58 @@ GNU Bison NEWS ** Warnings +*** Enhancements of the -Werror option + + The -Werror=CATEGORY option is now recognized, and will treat specified + warnings as errors. The warnings need not have been explicitly activated + using the -W option, this is similar to what GCC 4.7 does. + + For example, given the following command line, Bison will treat both + warnings related to POSIX Yacc incompatibilities and S/R conflicts as + errors (and only those): + + $ bison -Werror=yacc,error=conflicts-sr input.y + + If no categories are specified, -Werror will make all active warnings into + errors. For example, the following line does the same the previous example: + + $ bison -Werror -Wnone -Wyacc -Wconflicts-sr input.y + + (By default -Wconflicts-sr,conflicts-rr,deprecated,other is enabled.) + + Note that the categories in this -Werror option may not be prefixed with + "no-". However, -Wno-error[=CATEGORY] is valid. + + Note that -y enables -Werror=yacc. Therefore it is now possible to require + Yacc-like behavior (e.g., always generate y.tab.c), but to report + incompatibilities as warnings: "-y -Wno-error=yacc". + +*** The display of warnings is now richer + + The option that controls a given warning is now displayed: + + foo.y:4.6: warning: type clash on default action: != [-Wother] + + In the case of warnings treated as errors, the prefix is changed from + "warning: " to "error: ", and the suffix is displayed, in a manner similar + to GCC, as [-Werror=CATEGORY]. + + For instance, where the previous version of Bison would report (and exit + with failure): + + bison: warnings being treated as errors + input.y:1.1: warning: stray ',' treated as white space + + it now reports: + + input.y:1.1: error: stray ',' treated as white space [-Werror=other] + *** Deprecated constructs The new 'deprecated' warning category flags obsolete constructs whose support will be discontinued. It is enabled by default. These warnings used to be reported as 'other' warnings. -*** Warning categories are now displayed - - 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 @@ -90,9 +130,8 @@ GNU Bison NEWS foo.y: warning: 1 shift/reduce conflict [-Wconflicts-sr] foo.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr] $ bison -Werror foo.y - bison: warnings being treated as errors - foo.y: warning: 1 shift/reduce conflict [-Wconflicts-sr] - foo.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr] + foo.y: error: 1 shift/reduce conflict [-Werror=conflicts-sr] + foo.y: error: 2 reduce/reduce conflicts [-Werror=conflicts-rr] When %expect or %expect-rr is used, such as with bar.y: @@ -111,8 +150,8 @@ GNU Bison NEWS New one: $ bison bar.y - bar.y: shift/reduce conflicts: 1 found, 0 expected - bar.y: reduce/reduce conflicts: 2 found, 0 expected + bar.y: error: shift/reduce conflicts: 1 found, 0 expected + bar.y: error: reduce/reduce conflicts: 2 found, 0 expected ** Additional yylex/yyparse arguments @@ -156,14 +195,14 @@ GNU Bison NEWS used by the scanner, or rejecting invalid combinations from a factory invoked by the user actions). -** Variable api.tokens.prefix +** Variable api.token.prefix - The variable api.tokens.prefix changes the way tokens are identified in + The variable api.token.prefix changes the way tokens are identified in the generated files. This is especially useful to avoid collisions with identifiers in the target language. For instance %token FILE for ERROR - %define api.tokens.prefix "TOK_" + %define api.token.prefix "TOK_" %% start: FILE for ERROR; @@ -172,11 +211,15 @@ 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.namespace +** Renamed %define variables - The 'namespace' variable is renamed 'api.namespace'. Backward + The following variables have been renamed for consistency. Backward compatibility is ensured, but upgrading is recommended. + lr.default-reductions -> lr.default-reduction + lr.keep-unreachable-states -> lr.keep-unreachable-state + namespace -> api.namespace + ** Variable parse.error This variable controls the verbosity of error messages. The use of the @@ -199,6 +242,137 @@ GNU Bison NEWS * Noteworthy changes in release ?.? (????-??-??) [?] +** Changes in the format of error messages + + This used to be the format of many error reports: + + foo.y:5.10-24: result type clash on merge function 'merge': != + foo.y:4.13-27: previous declaration + + It is now: + + foo.y:5.10-25: result type clash on merge function 'merge': != + foo.y:4.13-27: previous declaration + +** Exception safety (lalr1.cc) + + The parse function now catches exceptions, uses the %destructors to + release memory (the lookahead symbol and the symbols pushed on the stack) + before re-throwing the exception. + + This feature is somewhat experimental. User feedback would be + appreciated. + +** New %define variable: api.location.type (glr.cc, lalr1.cc, lalr1.java) + + The %define variable api.location.type defines the name of the type to use + for locations. When defined, Bison no longer generates the position.hh + and location.hh files, nor does the parser will include them: the user is + then responsible to define her type. + + This can be used in programs with several parsers to factor their location + and position files: let one of them generate them, and the others just use + them. + + This feature was actually introduced, but not documented, in Bison 2.5, + under the name "location_type" (which is maintained for backward + compatibility). + + For consistency, lalr1.java's %define variables location_type and + position_type are deprecated in favor of api.location.type and + api.position.type. + +** Graph improvements in DOT and XSLT + + The graphical presentation of the states is more readable: their shape is + now rectangular, the state number is clearly displayed, and the items are + numbered and left-justified. + + The reductions are now explicitly represented as transitions to other + diamond shaped nodes. + + These changes are present in both --graph output and xml2dot.xsl XSLT + processing, with minor (documented) differences. + + Two nodes were added to the documentation: Xml and Graphviz. + +* Noteworthy changes in release ?.? (????-??-??) [?] + +** Bug fixes + + Warnings about uninitialized yylloc in yyparse have been fixed. + +** Documentation + + The sections about shift/reduce and reduce/reduce conflicts resolution + have been fixed and extended. + +* Noteworthy changes in release 2.6.5 (2012-11-07) [stable] + + We consider compiler warnings about Bison generated parsers to be bugs. + Rather than working around them in your own project, please consider + reporting them to us. + +** Bug fixes + + Warnings about uninitialized yylval and/or yylloc for push parsers with a + pure interface have been fixed for GCC 4.0 up to 4.8, and Clang 2.9 to + 3.2. + + Other issues in the test suite have been addressed. + + Nul characters are correctly displayed in error messages. + + When possible, yylloc is correctly initialized before calling yylex. It + is no longer necessary to initialize it in the %initial-action. + +* Noteworthy changes in release 2.6.4 (2012-10-23) [stable] + + Bison 2.6.3's --version was incorrect. This release fixes this issue. + +* Noteworthy changes in release 2.6.3 (2012-10-22) [stable] + +** Bug fixes + + Bugs and portability issues in the test suite have been fixed. + + Some errors in translations have been addressed, and --help now directs + users to the appropriate place to report them. + + Stray Info files shipped by accident are removed. + + Incorrect definitions of YY_, issued by yacc.c when no parser header is + generated, are removed. + + All the generated headers are self-contained. + +** Header guards (yacc.c, glr.c, glr.cc) + + In order to avoid collisions, the header guards are now + YY___INCLUDED, instead of merely _. + For instance the header generated from + + %define api.prefix "calc" + %defines "lib/parse.h" + + will use YY_CALC_LIB_PARSE_H_INCLUDED as guard. + +** Fix compiler warnings in the generated parser (yacc.c, glr.c) + + The compilation of pure parsers (%define api.pure) can trigger GCC + warnings such as: + + input.c: In function 'yyparse': + input.c:1503:12: warning: 'yylval' may be used uninitialized in this + function [-Wmaybe-uninitialized] + *++yyvsp = yylval; + ^ + + This is now fixed; pragmas to avoid these warnings are no longer needed. + + Warnings from clang ("equality comparison with extraneous parentheses" and + "function declared 'noreturn' should not return") have also been + addressed. * Noteworthy changes in release 2.6.2 (2012-08-03) [stable] @@ -256,7 +430,7 @@ GNU Bison NEWS * Noteworthy changes in release 2.6 (2012-07-19) [stable] -** Future changes: +** Future changes The next major release of Bison will drop support for the following deprecated features. Please report disagreements to bug-bison@gnu.org. @@ -2058,7 +2232,7 @@ along with this program. If not, see . 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 + LocalWords: TOK calc yyo fval Wconflicts Local Variables: mode: outline