errors: introduce the -Werror=CATEGORY option

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 1e660a2faf2d02b51d3d211545e8859e38291e61..7e5bda2d42a127866022083b5c56ac0a31ed7ee9 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -6,12 +6,19 @@ GNU Bison NEWS
 
 *** Obsolete features
 
 
 *** Obsolete features
 

-  Support for YYFAIL is removed, as announced since Bison 2.4.2.
+  Support for YYFAIL is removed (deprecated in Bison 2.4.2).

   Support for yystype and yyltype (instead of YYSTYPE and YYLTYPE)
   Support for yystype and yyltype (instead of YYSTYPE and YYLTYPE)

-  is removed, as announced in Bison 1.875.
+  is removed (deprecated in Bison 1.875).
+  Support for YYPARSE_PARAM is removed (deprecated in Bison 1.875).

 
 ** Warnings
 
 
 ** 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:
 *** Warning categories are now displayed
 
   For instance:


@@ -35,18 +42,17 @@ GNU Bison NEWS
     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
 
     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
 
     %printer    {} symbol1
     %destructor {} symbol2

+    %type <type>   symbol3

     %%
     exp: "a";
 
     %%
     exp: "a";
 

-  This is now only a warning.
-

 *** Useless destructors or printers
 
   Bison now warns about useless destructors or printers.  In the following
 *** Useless destructors or printers
 
   Bison now warns about useless destructors or printers.  In the following


@@ -61,6 +67,52 @@ GNU Bison NEWS
     %printer    {} token1 <type1> <type3>
     %destructor {} token2 <type2> <type4>
 
     %printer    {} token1 <type1> <type3>
     %destructor {} token2 <type2> <type4>
 

+*** Conflicts
+
+  The warnings and error messages about shift/reduce and reduce/reduce
+  conflicts have been normalized.  For instance on the following foo.y file:
+
+    %glr-parser
+    %%
+    exp: exp '+' exp | '0' | '0';
+
+  compare the previous version of bison:
+
+    $ bison foo.y
+    foo.y: conflicts: 1 shift/reduce, 2 reduce/reduce
+    $ bison -Werror foo.y
+    bison: warnings being treated as errors
+    foo.y: conflicts: 1 shift/reduce, 2 reduce/reduce
+
+  with the new behavior:
+
+    $ bison foo.y
+    foo.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
+    foo.y: warning: 2 reduce/reduce conflicts [-Wconflicts-rr]
+    $ bison -Werror foo.y
+    foo.y: error: 1 shift/reduce conflict [-Werror=conflicts-sr]
+    foo.y: error: 2 reduce/reduce conflicts [-Werror=conflicts-rr]
+
+  When %expect or %expect-rr is used, such as with bar.y:
+
+    %expect 0
+    %glr-parser
+    %%
+    exp: exp '+' exp | '0' | '0';
+
+  Former behavior:
+
+    $ bison bar.y
+    bar.y: conflicts: 1 shift/reduce, 2 reduce/reduce
+    bar.y: expected 0 shift/reduce conflicts
+    bar.y: expected 0 reduce/reduce conflicts
+
+  New one:
+
+    $ bison bar.y
+    bar.y: error: shift/reduce conflicts: 1 found, 0 expected
+    bar.y: error: reduce/reduce conflicts: 2 found, 0 expected
+

 ** Additional yylex/yyparse arguments
 
   The new directive %param declares additional arguments to both yylex and
 ** Additional yylex/yyparse arguments
 
   The new directive %param declares additional arguments to both yylex and


@@ -78,13 +130,19 @@ GNU Bison NEWS
 
 ** Java skeleton improvements
 
 
 ** 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
 
 
 ** C++ skeletons improvements
 

-*** locations are no longer mandatory (lalr1.cc, glr.cc)
+*** 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.
 
 
   Both lalr1.cc and glr.cc no longer require %location.
 


@@ -115,26 +173,73 @@ GNU Bison NEWS
 
 ** Variable api.namespace
 
 
 ** 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
 
   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
 
 
 ** 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
   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
-  run-time 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.
+
+** The directive %expect-rr is now an error in non GLR mode
+
+  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 ?.? (????-??-??) [?]
 

+** Bug fixes
+
+  Bugs 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.
+
+** Changes in the format of errors and exceptions output
+
+  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
+
+  It is now:
+
+    foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2>
+    foo.y:4.13-27:     previous declaration
+
+* 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
  Bison no longer executes user-specified M4 code when processing a grammar.
 
 ** Future Changes