GNU Bison NEWS
-* Noteworthy changes in release ?.? (????-??-??) [?]
+* Noteworthy changes in release 2.7 (2012-12-12) [stable]
** Bug fixes
Warnings about uninitialized yylloc in yyparse have been fixed.
-** %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.
-
-** New format for error reports: carets
+ Restored C90 compliance (yet no report was ever made).
- Caret errors have been added to Bison, for example (taken from the
- documentation):
+** Diagnostics are improved
- input.y:3.20-23: error: ambiguous reference: '$exp'
- exp: exp '+' exp { $exp = $1 + $2; };
- ^^^^
+*** Changes in the format of error messages
- The default behaviour for now is still not to display these unless explictly
- asked with -fall of -fcaret. However, in a later release, it will be made the
- default behavior (but may still be deactivated with -fno-caret).
+ This used to be the format of many error reports:
-** New value for %define variable: api.pure full
+ input.y:2.7-12: %type redeclaration for exp
+ input.y:1.7-12: previous declaration
- The %define variable api.pure requests a pure (reentrant) parser. However,
- for historical reasons, using it in a location-tracking Yacc parser resulted
- in an yyerror function that did not take a location as a parameter. With this
- new value, the user may request a better pure parser, where yyerror does take
- a location as a parameter (in location-tracking parsers).
+ It is now:
- The use of "%define api.pure true" is deprecated in favor of this new
- "%define api.pure full".
+ input.y:2.7-12: error: %type redeclaration for exp
+ input.y:1.7-12: previous declaration
-** Changes in the format of error messages
+*** New format for error reports: carets
- This used to be the format of many error reports:
+ Caret errors have been added to Bison:
- foo.y:5.10-24: result type clash on merge function 'merge': <t3> != <t2>
- foo.y:4.13-27: previous declaration
+ input.y:2.7-12: error: %type redeclaration for exp
+ %type <sval> exp
+ ^^^^^^
+ input.y:1.7-12: previous declaration
+ %type <ival> exp
+ ^^^^^^
- It is now:
+ or
- foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2>
- foo.y:4.13-27: previous declaration
+ input.y:3.20-23: error: ambiguous reference: '$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).
-** Exception safety (lalr1.cc)
+** New value for %define variable: api.pure full
- 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.
+ 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).
- This feature is somewhat experimental. User feedback would be
- appreciated.
+ 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.
+** 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
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.
+** %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.
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