*** Obsolete features
- Support for YYFAIL is removed (deprecated in Bison 2.4.2).
- Support for yystype and yyltype (instead of YYSTYPE and YYLTYPE)
- is removed (deprecated in Bison 1.875).
- Support for YYPARSE_PARAM is removed (deprecated in Bison 1.875).
+ Support for YYFAIL is removed (deprecated in Bison 2.4.2): use YYERROR.
+
+ Support for yystype and yyltype is removed (deprecated in Bison 1.875):
+ use YYSTYPE and YYLTYPE.
+
+ Support for YYLEX_PARAM and YYPARSE_PARAM is removed (deprecated in Bison
+ 1.875): use %lex-param, %parse-param, or %param.
** Warnings
+*** Carets
+
+ Version 2.7 introduced caret errors, for a prettier output. These are now
+ activated by default. The old format can still be used by invoking Bison
+ with -fno-caret (or -fnone).
+
*** Enhancements of the -Werror option
The -Werror=CATEGORY option is now recognized, and will treat specified
used by the scanner, or rejecting invalid combinations from a
factory invoked by the user actions).
+*** The epilogue is no longer affected by internal #defines
+
+ The glr.c skeleton uses defines such as #define yylval (yystackp->yyval) in
+ generated code. These weren't properly undefined before the inclusion of
+ the user epilogue, so functions such as the following were butchered by the
+ preprocessor expansion:
+
+ int yylex (yy::parser::semantic_type *yylval);
+
+ This is has been fixed: yylval, ynerrs, yychar, and yylloc are now valid
+ identifiers for user-provided variables.
+
+** Renamed %define variables
+
+ 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
+ stype -> api.value.type
+
** Variable api.token.prefix
The variable api.token.prefix changes the way tokens are identified in
use these prefixed token names, although the grammar itself still
uses the short names (as in the sample rule given above).
-** Renamed %define variables
-
- 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
It used to be an error only if used in non GLR mode, _and_ if there are
reduce/reduce conflicts.
-* Noteworthy changes in release ?.? (????-??-??) [?]
+* Noteworthy changes in release 2.7 (2012-12-12) [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.
+ Warnings about uninitialized yylloc in yyparse have been fixed.
- Incorrect definitions of YY_, issued by yacc.c when no parser header is
- generated, are removed.
+ Restored C90 compliance (yet no report was ever made).
- All the generated headers are self-contained.
+** Diagnostics are improved
-** Changes in the format of error messages
+*** 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': <t3> != <t2>
- foo.y:4.13-27: previous declaration
+ input.y:2.7-12: %type redeclaration for exp
+ input.y:1.7-12: previous declaration
It is now:
- foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2>
- foo.y:4.13-27: previous declaration
+ input.y:2.7-12: error: %type redeclaration for exp
+ input.y:1.7-12: previous declaration
-** Header guards (yacc.c, glr.c, glr.cc)
+*** New format for error reports: carets
- In order to avoid collisions, the header guards are now
- YY_<PREFIX>_<FILE>_INCLUDED, instead of merely <PREFIX>_<FILE>.
- For instance the header generated from
+ Caret errors have been added to Bison:
- %define api.prefix "calc"
- %defines "lib/parse.h"
+ input.y:2.7-12: error: %type redeclaration for exp
+ %type <sval> exp
+ ^^^^^^
+ input.y:1.7-12: previous declaration
+ %type <ival> exp
+ ^^^^^^
- will use YY_CALC_LIB_PARSE_H_INCLUDED as guard.
+ 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)
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_<PREFIX>_<FILE>_INCLUDED, instead of merely <PREFIX>_<FILE>.
+ 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
"function declared 'noreturn' should not return") have also been
addressed.
-** 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.
-
* Noteworthy changes in release 2.6.2 (2012-08-03) [stable]
** Bug fixes
* 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.
These features are experimental in this version. More user feedback
will help to stabilize them.
+ Contributed by Alex Rozenman.
** IELR(1) and canonical LR(1):
The current Java interface is experimental and may evolve. More user
feedback will help to stabilize it.
+ Contributed by Paolo Bonzini.
** %language
Bison can now generate an XML report of the LALR(1) automaton using the new
"--xml" option. The current XML schema is experimental and may evolve. More
user feedback will help to stabilize it.
+ Contributed by Wojciech Polak.
** The grammar file may now specify the name of the parser header file using
%defines. For example:
projects / bison.git / blobdiff