Path: csiph.com!newsfeed.hal-mli.net!feeder3.hal-mli.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!news.misty.com!news.iecc.com!.POSTED!nerds-end From: Akim Demaille Newsgroups: comp.compilers Subject: Bison 2.7 is released Date: Wed, 12 Dec 2012 17:12:51 +0100 Organization: Compilers Central Lines: 512 Sender: johnl@iecc.com Approved: comp.compilers@iecc.com Message-ID: <12-12-006@comp.compilers> NNTP-Posting-Host: news.iecc.com Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\)) Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit X-Trace: leila.iecc.com 1355334266 39693 64.57.183.58 (12 Dec 2012 17:44:26 GMT) X-Complaints-To: abuse@iecc.com NNTP-Posting-Date: Wed, 12 Dec 2012 17:44:26 +0000 (UTC) Keywords: bison, available Posted-Date: 12 Dec 2012 12:44:26 EST X-submission-address: compilers@iecc.com X-moderator-address: compilers-request@iecc.com X-FAQ-and-archives: http://compilers.iecc.com Xref: csiph.com comp.compilers:790 The Bison team is happy to announce the release of Bison 2.7. There are many nice new features (especially in the way the diagnostics are produced, and in the graph representation of the parser), implemented by Thiophile Ranquet for most of them. See the list below. Cheers! Here are the compressed sources: ftp://ftp.gnu.org/gnu/bison/bison-2.7.tar.gz (3.0MB) ftp://ftp.gnu.org/gnu/bison/bison-2.7.tar.xz (1.7MB) Here are the GPG detached signatures[*]: ftp://ftp.gnu.org/gnu/bison/bison-2.7.tar.gz.sig ftp://ftp.gnu.org/gnu/bison/bison-2.7.tar.xz.sig Use a mirror for higher download bandwidth: http://www.gnu.org/order/ftp.html [*] Use a .sig file to verify that the corresponding file (without the .sig suffix) is intact. First, be sure to download both the .sig file and the corresponding tarball. Then, run a command like this: gpg --verify bison-2.7.tar.gz.sig If that command fails because you don't have the required public key, then run this command to import it: gpg --keyserver keys.gnupg.net --recv-keys 0DDCAA3278D5264E and rerun the 'gpg --verify' command. This release was bootstrapped with the following tools: Autoconf 2.69 Automake 1.12.5 Flex 2.5.37 Gettext 0.18.1 Gnulib v0.0-7741-g4a8c422 Since I believe the latest announcement here was about Bison 2.5, please find below the user visible changes since then. * Noteworthy changes in release 2.7 (2012-12-12) [stable] ** Bug fixes Warnings about uninitialized yylloc in yyparse have been fixed. Restored C90 compliance (yet no report was ever made). ** Diagnostics are improved *** Changes in the format of error messages This used to be the format of many error reports: input.y:2.7-12: %type redeclaration for exp input.y:1.7-12: previous declaration It is now: input.y:2.7-12: error: %type redeclaration for exp input.y:1.7-12: previous declaration *** New format for error reports: carets Caret errors have been added to Bison: input.y:2.7-12: error: %type redeclaration for exp %type exp ^^^^^^ input.y:1.7-12: previous declaration %type exp ^^^^^^ or input.y:3.20-23: error: ambiguous reference: '$exp' exp: exp '+' exp { $exp = $1 + $3; }; ^^^^ input.y:3.1-3: refers to: $exp at $$ exp: exp '+' exp { $exp = $1 + $3; }; ^^^ input.y:3.6-8: refers to: $exp at $1 exp: exp '+' exp { $exp = $1 + $3; }; ^^^ input.y:3.14-16: refers to: $exp at $3 exp: exp '+' exp { $exp = $1 + $3; }; ^^^ The default behaviour for now is still not to display these unless explictly asked with -fcaret (or -fall). However, in a later release, it will be made the default behavior (but may still be deactivated with -fno-caret). ** New value for %define variable: api.pure full The %define variable api.pure requests a pure (reentrant) parser. However, for historical reasons, using it in a location-tracking Yacc parser resulted in a yyerror function that did not take a location as a parameter. With this new value, the user may request a better pure parser, where yyerror does take a location as a parameter (in location-tracking parsers). The use of "%define api.pure true" is deprecated in favor of this new "%define api.pure full". ** 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. ** 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. ** 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. ** %language is no longer an experimental feature. The introduction of this feature, in 2.4, was four years ago. The --language option and the %language directive are no longer experimental. ** Documentation The sections about shift/reduce and reduce/reduce conflicts resolution have been fixed and extended. Although introduced more than four years ago, XML and Graphviz reports were not properly documented. The translation of mid-rule actions is now described. * 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] ** Bug fixes Buffer overruns, complaints from Flex, and portability issues in the test suite have been fixed. ** Spaces in %lex- and %parse-param (lalr1.cc, glr.cc) Trailing end-of-lines in %parse-param or %lex-param would result in invalid C++. This is fixed. ** Spurious spaces and end-of-lines The generated files no longer end (nor start) with empty lines. * Noteworthy changes in release 2.6.1 (2012-07-30) [stable] 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 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, 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. ** Generated Parser Headers *** Guards (yacc.c, glr.c, glr.cc) The generated headers are now guarded, as is already the case for C++ parsers (lalr1.cc). For instance, with --defines=foo.h: #ifndef YY_FOO_H # define YY_FOO_H ... #endif /* !YY_FOO_H */ *** New declarations (yacc.c, glr.c) The generated header now declares yydebug and yyparse. Both honor --name-prefix=bar_, and yield int bar_parse (void); rather than #define yyparse bar_parse int yyparse (void); 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: The next major release will drop support for generating parsers in K&R C. ** yacc.c: YYBACKUP works as expected. ** glr.c improvements: *** Location support is eliminated when not requested: GLR parsers used to include location-related code even when locations were not requested, and therefore not even usable. *** __attribute__ is preserved: __attribute__ is no longer disabled when __STRICT_ANSI__ is defined (i.e., when -std is passed to GCC). ** lalr1.java: several fixes: The Java parser no longer throws ArrayIndexOutOfBoundsException if the first token leads to a syntax error. Some minor clean ups. ** Changes for C++: *** C++11 compatibility: C and C++ parsers use "nullptr" instead of "0" when __cplusplus is 201103L or higher. *** Header guards 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 The inclusion guard is now computed from "PREFIX/FILE-NAME", where lower case characters are converted to upper case, and series of non-alphanumerical characters are converted to an underscore. 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 *** C++ locations: The position and location constructors (and their initialize methods) accept new arguments for line and column. Several issues in the documentation were fixed. ** liby is no longer asking for "rpl_fprintf" on some platforms. ** Changes in the manual: *** %printer is documented The "%printer" directive, supported since at least Bison 1.50, is finally documented. The "mfcalc" example is extended to demonstrate it. For consistency with the C skeletons, the C++ parsers now also support "yyoutput" (as an alias to "debug_stream ()"). *** Several improvements have been made: The layout for grammar excerpts was changed to a more compact scheme. Named references are motivated. The description of the automaton description file (*.output) is updated to the current format. Incorrect index entries were fixed. Some other errors were fixed. ** Building bison: *** Conflicting prototypes with recent/modified Flex. Fixed build problems with the current, unreleased, version of Flex, and some modified versions of 2.5.35, which have modified function prototypes. *** Warnings during the build procedure have been eliminated. *** Several portability problems in the test suite have been fixed: This includes warnings with some compilers, unexpected behavior of tools such as diff, warning messages from the test suite itself, etc. *** The install-pdf target works properly: Running "make install-pdf" (or -dvi, -html, -info, and -ps) no longer halts in the middle of its course.