misc: document TESTSUITEFLAGS in README-hacking

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 74afbfacab1c1ceabea40264a079fda97fe9aa54..346c4da4be17a4481251f5c37c068ed350235235 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -13,17 +13,57 @@ GNU Bison NEWS
 
 ** Warnings
 
 
 ** Warnings
 

-*** Deprecated constructs
+*** Enhancements of the -Werror option

 
 

-  A new warning category, 'deprecated', is used to flag obsolete constructs
-  whose support will be discontinued.  It is enabled by default.  These
-  warnings used to be reported as 'other' warnings.
+  The -Werror=CATEGORY option is now recognized, and will treat specified
+  warnings as errors. The warnings need not have been explicitly activated
+  using the -W option, this is similar to what GCC 4.7 does.

 
 

-*** Warning categories are now displayed
+  For example, given the following command line, Bison will treat both
+  warnings related to POSIX Yacc incompatibilities and S/R conflicts as
+  errors (and only those):

 
 

-  For instance:
+    $ 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):
+
+    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

 
 

-  foo.y:4.6: warning: type clash on default action: <foo> != <bar> [-Wother]
+  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
 


@@ -67,6 +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


@@ -84,9 +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
 


@@ -109,14 +195,14 @@ GNU Bison NEWS
   used by the scanner, or rejecting invalid combinations from a
   factory invoked by the user actions).
 
   used by the scanner, or rejecting invalid combinations from a
   factory invoked by the user actions).
 

-** Variable api.tokens.prefix
+** Variable api.token.prefix

 
 

-  The variable api.tokens.prefix changes the way tokens are identified in
+  The variable api.token.prefix changes the way tokens are identified in

   the generated files.  This is especially useful to avoid collisions
   with identifiers in the target language.  For instance
 
     %token FILE for ERROR
   the generated files.  This is especially useful to avoid collisions
   with identifiers in the target language.  For instance
 
     %token FILE for ERROR

-    %define api.tokens.prefix "TOK_"
+    %define api.token.prefix "TOK_"

     %%
     start: FILE for ERROR;
 
     %%
     start: FILE for ERROR;
 


@@ -125,28 +211,118 @@ GNU Bison NEWS
   use these prefixed token names, although the grammar itself still
   uses the short names (as in the sample rule given above).
 
   use these prefixed token names, although the grammar itself still
   uses the short names (as in the sample rule given above).
 

-** Variable api.namespace
+** Renamed %define variables

 
 

-  The "namespace" variable is renamed "api.namespace".  Backward
+  The following variables have been renamed for consistency.  Backward

   compatibility is ensured, but upgrading is recommended.
 
   compatibility is ensured, but upgrading is recommended.
 

+    lr.default-reductions      -> lr.default-reduction
+    lr.keep-unreachable-states -> lr.keep-unreachable-state
+    namespace                  -> api.namespace
+

 ** Variable parse.error
 
 ** 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 and portability issues 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.
+
+  All the generated headers are self-contained.
+
+** 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.
+
+** 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.
+
+** Fix compiler warnings in the generated parser (yacc.c, glr.c)
+
+  The compilation of pure parsers (%define api.pure) can trigger GCC
+  warnings such as:
+
+    input.c: In function 'yyparse':
+    input.c:1503:12: warning: 'yylval' may be used uninitialized in this
+                              function [-Wmaybe-uninitialized]
+       *++yyvsp = yylval;
+                ^
+
+  This is now fixed; pragmas to avoid these warnings are no longer needed.
+
+  Warnings from clang ("equality comparison with extraneous parentheses" and
+  "function declared 'noreturn' should not return") have also been
+  addressed.
+
+** New %define variable: api.location.type (glr.cc, lalr1.cc, lalr1.java)
+
+  The %define variable api.location.type defines the name of the type to use
+  for locations.  When defined, Bison no longer generates the position.hh
+  and location.hh files, nor does the parser will include them: the user is
+  then responsible to define her type.
+
+  This can be used in programs with several parsers to factor their location
+  and position files: let one of them generate them, and the others just use
+  them.
+
+  This feature was actually introduced, but not documented, in Bison 2.5,
+  under the name "location_type" (which is maintained for backward
+  compatibility).
+
+  For consistency, lalr1.java's %define variables location_type and
+  position_type are deprecated in favor of api.location.type and
+  api.position.type.

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


@@ -2006,7 +2182,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
  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:  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
+ LocalWords:  TOK calc yyo fval Wconflicts

 
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