scan-skel: split @directive functions

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 8f52f80c6fabc3b263de2bfe6532c2b89d3b1ff6..a5c7a99dff06984aef67a8a624702428a6547729 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -13,11 +13,57 @@ GNU Bison NEWS
 
 ** Warnings
 
 
 ** Warnings
 

-*** Warning categories are now displayed
+*** Enhancements of the -Werror option

 
 

-  For instance:
+  The -Werror=CATEGORY option is now recognized, and will treat specified
+  warnings as errors. The warnings need not have been explictly activated
+  using the -W option, this is similar to what gcc 4.7 does.
+
+  For example, given the following command line, Bison will treat both
+  warnings related to POSIX Yacc incompatiblities and S/R conflicts as
+  errors (and only those):
+
+    $ bison -Werror=yacc,error=conflicts-sr input.y
+
+  If no categories are specified, -Werror will make all active warnings into
+  errors. For example, the following line does the same the previous example:
+
+    $ bison -Werror -Wnone -Wyacc -Wconflicts-sr input.y
+
+  (By default -Wconflicts-sr,conflicts-rr,deprecated,other is enabled.)
+
+  Note that the categories in this -Werror option may not be prefixed with
+  "no-". However, -Wno-error[=CATEGORY] is valid.
+
+  Note that -y enables -Werror=yacc. Therefore it is now possible to require
+  Yacc-like behavior (e.g., always generate y.tab.c), but to report
+  incompatibilities as warnings: "-y -Wno-error=yacc".
+
+*** The display of warnings is now richer
+
+  The option that controls a given warning is now displayed:
+
+    foo.y:4.6: warning: type clash on default action: <foo> != <bar> [-Wother]
+
+  In the case of warnings treated as errors, the prefix is changed from
+  "warning: " to "error: ", and the suffix is displayed, in a manner similar
+  to gcc, as [-Werror=CATEGORY].
+
+  For instance, where the previous version of Bison would report (and exit
+  with failure):

 
 

-  foo.y:4.6: warning: type clash on default action: <foo> != <bar> [-Wother]
+    bison: warnings being treated as errors
+    input.y:1.1: warning: stray ',' treated as white space
+
+  it now reports:
+
+    input.y:1.1: error: stray ',' treated as white space [-Werror=other]
+
+*** 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.

 
 *** Useless semantic types
 
 
 *** Useless semantic types
 


@@ -36,18 +82,17 @@ 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


@@ -62,6 +107,52 @@ 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


@@ -79,9 +170,9 @@ 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
 


@@ -122,26 +213,65 @@ 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 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
+
+  It is now:
+
+    foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2>
+    foo.y:4.13-27:     previous declaration
+
+** 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.

 
 * Noteworthy changes in release 2.6.2 (2012-08-03) [stable]
 
 
 * Noteworthy changes in release 2.6.2 (2012-08-03) [stable]