skeletons: simplify the protections against "unused" warnings.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 144aae850c583423d5bc718e0f46891f531e72dd..a9922c0994f471eba079e6f0c496ca8f14bfe146 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -60,7 +60,15 @@ Bison News
   allow the programmer to prune possible parses based on the values of
   runtime expressions.
 
   allow the programmer to prune possible parses based on the values of
   runtime expressions.
 

-* Changes in version 2.5 (????-??-??):
+* Changes in version 2.5.1 (????-??-??):
+
+** Some portability problems in the test suite have been fixed.
+
+** Minor improvements have been made to the manual.
+
+** YYBACKUP works as expected.
+
+* Changes in version 2.5 (2011-05-14):

 
 ** Grammar symbol names can now contain non-initial dashes:
 
 
 ** Grammar symbol names can now contain non-initial dashes:
 


@@ -80,12 +88,12 @@ Bison News
   When no ambiguity is possible, original symbol names may be used
   as named references:
 
   When no ambiguity is possible, original symbol names may be used
   as named references:
 

-    if_stmt : 'if' cond_expr 'then' then_stmt ';'
+    if_stmt : "if" cond_expr "then" then_stmt ';'

     { $if_stmt = mk_if_stmt($cond_expr, $then_stmt); }
 
   In the more common case, explicit names may be declared:
 
     { $if_stmt = mk_if_stmt($cond_expr, $then_stmt); }
 
   In the more common case, explicit names may be declared:
 

-    stmt[res] : 'if' expr[cond] 'then' stmt[then] 'else' stmt[else] ';'
+    stmt[res] : "if" expr[cond] "then" stmt[then] "else" stmt[else] ';'

     { $res = mk_if_stmt($cond, $then, $else); }
 
   Location information is also accessible using @name syntax.  When
     { $res = mk_if_stmt($cond, $then, $else); }
 
   Location information is also accessible using @name syntax.  When


@@ -99,7 +107,7 @@ Bison News
 
   IELR(1) is a minimal LR(1) parser table generation algorithm.  That
   is, given any context-free grammar, IELR(1) generates parser tables
 
   IELR(1) is a minimal LR(1) parser table generation algorithm.  That
   is, given any context-free grammar, IELR(1) generates parser tables

-  with the full language recognition power of canonical LR(1) but with
+  with the full language-recognition power of canonical LR(1) but with

   nearly the same number of parser states as LALR(1).  This reduction
   in parser states is often an order of magnitude.  More importantly,
   because canonical LR(1)'s extra parser states may contain duplicate
   nearly the same number of parser states as LALR(1).  This reduction
   in parser states is often an order of magnitude.  More importantly,
   because canonical LR(1)'s extra parser states may contain duplicate


@@ -184,7 +192,7 @@ Bison News
   except that the manner in which Bison processes multiple definitions
   for the same NAME differs.  Most importantly, -F and --force-define
   quietly override %define, but -D and --define do not.  For further
   except that the manner in which Bison processes multiple definitions
   for the same NAME differs.  Most importantly, -F and --force-define
   quietly override %define, but -D and --define do not.  For further

-  details, see the section "Bison Options" in the Bison manual.
+  details, see the section `Bison Options' in the Bison manual.

 
 *** Variables renamed:
 
 
 *** Variables renamed:
 


@@ -201,7 +209,7 @@ Bison News
   The old names are now deprecated but will be maintained indefinitely
   for backward compatibility.
 
   The old names are now deprecated but will be maintained indefinitely
   for backward compatibility.
 

-*** Values no longer need to be quoted in grammar file:
+*** Values no longer need to be quoted in the grammar file:

 
   If a %define value is an identifier, it no longer needs to be placed
   within quotations marks.  For example,
 
   If a %define value is an identifier, it no longer needs to be placed
   within quotations marks.  For example,


@@ -242,8 +250,8 @@ Bison News
 
   Similarly to the C parsers, the C++ parsers now define the YYRHSLOC
   macro and use it in the default YYLLOC_DEFAULT.  You are encouraged
 
   Similarly to the C parsers, the C++ parsers now define the YYRHSLOC
   macro and use it in the default YYLLOC_DEFAULT.  You are encouraged

-  to use it.  If, for instance, your location structure has "first"
-  and "last" members, instead of
+  to use it.  If, for instance, your location structure has `first'
+  and `last' members, instead of

 
       # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
         do                                                                 \
 
       # define YYLLOC_DEFAULT(Current, Rhs, N)                             \
         do                                                                 \


@@ -325,7 +333,7 @@ Bison News
     in order to detect a syntax error.  Because no unexpected token or
     expected tokens can then be reported, the verbose syntax error
     message described above is suppressed, and the parser instead
     in order to detect a syntax error.  Because no unexpected token or
     expected tokens can then be reported, the verbose syntax error
     message described above is suppressed, and the parser instead

-    reports the simpler message, "syntax error".  Previously, this
+    reports the simpler message, `syntax error'.  Previously, this

     suppression was sometimes erroneously triggered by %nonassoc when a
     lookahead was actually required.  Now verbose messages are
     suppressed only when all previous lookaheads have already been
     suppression was sometimes erroneously triggered by %nonassoc when a
     lookahead was actually required.  Now verbose messages are
     suppressed only when all previous lookaheads have already been


@@ -357,6 +365,61 @@ Bison News
 *** The top element of each of the value stack and location stack is now
     cleared when popped so that it can be garbage collected.
 
 *** The top element of each of the value stack and location stack is now
     cleared when popped so that it can be garbage collected.
 

+*** Parser traces now print the top element of the stack.
+
+** -W/--warnings fixes:
+
+*** Bison now properly recognizes the `no-' versions of categories:
+
+  For example, given the following command line, Bison now enables all
+  warnings except warnings for incompatibilities with POSIX Yacc:
+
+    bison -Wall,no-yacc gram.y
+
+*** Bison now treats S/R and R/R conflicts like other warnings:
+
+  Previously, conflict reports were independent of Bison's normal
+  warning system.  Now, Bison recognizes the warning categories
+  `conflicts-sr' and `conflicts-rr'.  This change has important
+  consequences for the -W and --warnings command-line options.  For
+  example:
+
+    bison -Wno-conflicts-sr gram.y  # S/R conflicts not reported
+    bison -Wno-conflicts-rr gram.y  # R/R conflicts not reported
+    bison -Wnone            gram.y  # no conflicts are reported
+    bison -Werror           gram.y  # any conflict is an error
+
+  However, as before, if the %expect or %expect-rr directive is
+  specified, an unexpected number of conflicts is an error, and an
+  expected number of conflicts is not reported, so -W and --warning
+  then have no effect on the conflict report.
+
+*** The `none' category no longer disables a preceding `error':
+
+  For example, for the following command line, Bison now reports
+  errors instead of warnings for incompatibilities with POSIX Yacc:
+
+    bison -Werror,none,yacc gram.y
+
+*** The `none' category now disables all Bison warnings:
+
+  Previously, the `none' category disabled only Bison warnings for
+  which there existed a specific -W/--warning category.  However,
+  given the following command line, Bison is now guaranteed to
+  suppress all warnings:
+
+    bison -Wnone gram.y
+
+** Precedence directives can now assign token number 0:
+
+  Since Bison 2.3b, which restored the ability of precedence
+  directives to assign token numbers, doing so for token number 0 has
+  produced an assertion failure.  For example:
+
+    %left END 0
+
+  This bug has been fixed.
+

 * Changes in version 2.4.3 (2010-08-05):
 
 ** Bison now obeys -Werror and --warnings=error for warnings about
 * Changes in version 2.4.3 (2010-08-05):
 
 ** Bison now obeys -Werror and --warnings=error for warnings about


@@ -835,26 +898,26 @@ Bison News
   if the symbols have destructors.  For instance:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }
   if the symbols have destructors.  For instance:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; }

-       | exp "+" exp
-       ;
+        | exp "+" exp
+        ;

 
   will trigger a warning about $$ and $5 in the first rule, and $3 in
   the second ($1 is copied to $$ by the default rule).  This example
   most likely contains three errors, and could be rewritten as:
 
      exp: exp "?" exp ":" exp
 
   will trigger a warning about $$ and $5 in the first rule, and $3 in
   the second ($1 is copied to $$ by the default rule).  This example
   most likely contains three errors, and could be rewritten as:
 
      exp: exp "?" exp ":" exp

-           { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
-       | exp "+" exp
-           { $$ = $1 ? $1 : $3; if ($1) free ($3); }
-       ;
+            { $$ = $1 ? $3 : $5; free ($1 ? $5 : $3); free ($1); }
+        | exp "+" exp
+            { $$ = $1 ? $1 : $3; if ($1) free ($3); }
+        ;

 
   However, if the original actions were really intended, memory leaks
   and all, the warnings can be suppressed by letting Bison believe the
   values are used, e.g.:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }
 
   However, if the original actions were really intended, memory leaks
   and all, the warnings can be suppressed by letting Bison believe the
   values are used, e.g.:
 
      exp: exp "?" exp ":" exp { $1 ? $1 : $3; (void) ($$, $5); }

-       | exp "+" exp         { $$ = $1; (void) $3; }
-       ;
+        | exp "+" exp         { $$ = $1; (void) $3; }
+        ;

 
   If there are mid-rule actions, the warning is issued if no action
   uses it.  The following triggers no warning: $1 and $3 are used.
 
   If there are mid-rule actions, the warning is issued if no action
   uses it.  The following triggers no warning: $1 and $3 are used.


@@ -1098,16 +1161,16 @@ Bison News
   In agreement with POSIX and with other Yaccs, leaving a default
   action is valid when $$ is untyped, and $1 typed:
 
   In agreement with POSIX and with other Yaccs, leaving a default
   action is valid when $$ is untyped, and $1 typed:
 

-       untyped: ... typed;
+        untyped: ... typed;

 
   but the converse remains an error:
 
 
   but the converse remains an error:
 

-       typed: ... untyped;
+        typed: ... untyped;

 
 ** Values of mid-rule actions
   The following code:
 
 
 ** Values of mid-rule actions
   The following code:
 

-       foo: { ... } { $$ = $1; } ...
+        foo: { ... } { $$ = $1; } ...

 
   was incorrectly rejected: $1 is defined in the second mid-rule
   action, and is equal to the $$ of the first mid-rule action.
 
   was incorrectly rejected: $1 is defined in the second mid-rule
   action, and is equal to the $$ of the first mid-rule action.


@@ -1518,7 +1581,7 @@ End:
 
 -----
 
 
 -----
 

-Copyright (C) 1995-2011 Free Software Foundation, Inc.
+Copyright (C) 1995-2012 Free Software Foundation, Inc.

 
 This file is part of Bison, the GNU Parser Generator.
 
 
 This file is part of Bison, the GNU Parser Generator.