* Comment fixes.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 2b7c1013ba90e9607a28c85f0162bce884e5ac73..e982759c2a2724a709ec6d64b4866a6a32d40857 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,9 @@ Bison News
 
 Changes in version 2.1a:
 
+* Bison now allows multiple %union declarations, and concatenates
+  their contents together.
+
 * New warning: unused values
   Typed right-hand side symbols whose value are not used are reported.
   For instance:
@@ -26,6 +29,17 @@ Changes in version 2.1a:
        | 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.
+
+     exp: exp { push ($1); } '+' exp { push ($3); sum (); };
+
+  Mid-rule actions that use $$ cause the corresponding value to be
+  set, therefore the following action must use it.  The following rule
+  triggers a warning about $2.
+
+     exp: '1' { $$ = 1; } '+' exp { $$ = $1 + $4; };
+
   The warning is intended to help catching lost values and memory leaks.
   If a value is ignored, its associated memory typically is not reclaimed.
 
@@ -684,8 +698,8 @@ End:
 
 -----
 
-Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
-Free Software Foundation, Inc.
+Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
+2004, 2005, 2006 Free Software Foundation, Inc.
 
 This file is part of Bison, the GNU Compiler Compiler.