Split the default %destructor/%printer into two kinds: <*> and <!>.

[bison.git] / NEWS

diff --git a/NEWS b/NEWS
index 75e0284ffaae4a4095637ee216f8147ef9a0d667..c3fe6d03773edee3183bba7eaab49a02c4c9f3ba 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,25 @@ Changes in version 2.3a+ (????-??-??):
 * The -g and --graph options now output graphs in Graphviz DOT format,
   not VCG format.
 
+* Bison now recognizes two separate kinds of default %destructor's and
+  %printer's:
+
+    1. Place `<*>' in a %destructor/%printer symbol list to define a default
+       %destructor/%printer for all grammar symbols for which you have formally
+       declared semantic type tags.
+
+    2. Place `<!>' in a %destructor/%printer symbol list to define a default
+       %destructor/%printer for all grammar symbols without declared semantic
+       type tags.
+
+  Bison no longer supports the `%symbol-default' notation from Bison 2.3a.
+  `<*>' and `<!>' combined achieve the same effect with one exception: Bison no
+  longer applies any %destructor to a mid-rule value if that mid-rule value is
+  not actually ever referenced using either $$ or $n in a semantic action.
+
+  See the section `Freeing Discarded Symbols' in the Bison manual for further
+  details.
+
 * The Yacc prologue alternatives from Bison 2.3a have been rewritten as the
   following directives: