* Noteworthy changes in release ?.? (????-??-??) [?]
+** Incompatible changes
+
+*** 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).
+
** Warnings
-*** Warning categories are now diplayed in warnings
+*** 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:
3.28-34: warning: type <type3> is used, but is not associated to any symbol
4.28-34: warning: type <type4> is used, but is not associated to any symbol
-*** Undeclared symbols
+*** Undefined but unused symbols
- Bison used to raise an error for %printer and %destructor directives for
- undefined symbols.
+ Bison used to raise an error for undefined symbols that are not used in
+ the grammar. This is now only a warning.
%printer {} symbol1
%destructor {} symbol2
+ %type <type> symbol3
%%
exp: "a";
- This is now only a warning.
-
*** Useless destructors or printers
Bison now warns about useless destructors or printers. In the following
** Java skeleton improvements
- The constants for token names were moved to the Lexer interface.
- Also, it is possible to add code to the parser's constructors using
- "%code init" and "%define init_throws".
+ The constants for token names were moved to the Lexer interface. Also, it
+ is possible to add code to the parser's constructors using "%code init"
+ and "%define init_throws".
+
+** C++ skeletons improvements
+
+*** The parser header is no longer mandatory (lalr1.cc, glr.cc)
+
+ Using %defines is now optional. Without it, the needed support classes
+ are defined in the generated parser, instead of additional files (such as
+ location.hh, position.hh and stack.hh).
+
+*** Locations are no longer mandatory (lalr1.cc, glr.cc)
+
+ Both lalr1.cc and glr.cc no longer require %location.
-** C++ skeleton improvements
+*** syntax_error exception (lalr1.cc)
The C++ parser features a syntax_error exception, which can be
thrown from the scanner or from user rules to raise syntax errors.
** Variable api.namespace
- The "namespace" variable is renamed "api.namespace". Backward
+ The 'namespace' variable is renamed 'api.namespace'. Backward
compatibility is ensured, but upgrading is recommended.
** Variable parse.error
- The variable error controls the verbosity of error messages. The
- use of the %error-verbose directive is deprecated in favor of
- %define parse.error "verbose".
+ This variable controls the verbosity of error messages. The use of the
+ %error-verbose directive is deprecated in favor of "%define parse.error
+ verbose".
** Semantic predicates
- The new, experimental, semantic-predicate feature allows actions of
- the form %?{ BOOLEAN-EXPRESSION }, which cause syntax errors (as for
+ The new, experimental, semantic-predicate feature allows actions of the
+ form "%?{ BOOLEAN-EXPRESSION }", which cause syntax errors (as for
YYERROR) if the expression evaluates to 0, and are evaluated immediately
- in GLR parsers, rather than being deferred. The result is that they
- allow the programmer to prune possible parses based on the values of
- runtime expressions.
+ in GLR parsers, rather than being deferred. The result is that they allow
+ the programmer to prune possible parses based on the values of run-time
+ expressions.
* Noteworthy changes in release ?.? (????-??-??) [?]
-** Future changes
+
+* 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)", $<ival>$, $<fval>$); } <*> <>;
+
+ 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&C parsers
+*** K&R C parsers
Support for generating parsers in K&R C will be removed. Parsers
- generated for C supprt ISO C90, and are tested with ISO C99 and ISO C11
+ generated for C support ISO C90, and are tested with ISO C99 and ISO C11
compilers.
*** Features deprecated since Bison 1.875
because existing versions of ylwrap (e.g., Automake 1.12.1) do not support
it.
-** Headers
+** 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 intance, with --defines=foo.h:
+ parsers (lalr1.cc). For instance, with --defines=foo.h:
#ifndef YY_FOO_H
# define YY_FOO_H
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 <ival> FOO %token <ival> 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:
- a single argument only can be added,
- their types are weak (void *),
- - this context is not passed to anciliary functions such as yyerror,
+ - this context is not passed to ancillary functions such as yyerror,
- only yacc.c parsers support them.
The new %parse-param/%lex-param directives provide a more precise control.
LocalWords: struct yystype DJGPP lex param Haible NUM alloca YYSTACK NUL goto
LocalWords: YYMAXDEPTH Unescaped UCNs YYLTYPE's yyltype typedefs inline Yaccs
LocalWords: Heriyanto Reenable dprec Hilfinger Eggert MYEOF Folle Menezes EOF
- LocalWords: Lackovic define's itemset Groff Gettext malloc NEWS'ed YYDEBUG
+ LocalWords: Lackovic define's itemset Groff Gettext malloc NEWS'ed YYDEBUG YY
LocalWords: namespaces strerror const autoconfiguration Dconst Autoconf's FDL
- LocalWords: Automake TMPDIR LESSEQ
+ 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
Local Variables:
mode: outline
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