*** 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
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
-** Changes in the format of error messages
+ 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:
- 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
-** Exception safety (lalr1.cc)
+*** New format for error reports: carets
- 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.
+ Caret errors have been added to Bison:
- This feature is somewhat experimental. User feedback would be
- appreciated.
+ input.y:2.7-12: error: %type redeclaration for exp
+ %type <sval> exp
+ ^^^^^^
+ input.y:1.7-12: previous declaration
+ %type <ival> 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)
position_type are deprecated in favor of api.location.type and
api.position.type.
-** Graphviz improvements
+** 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
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.
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