diff --git a/ChangeLog b/ChangeLog
index 98cc2c1..b02a142 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sat May 23 22:31:06 2009  Minero Aoki  <aamine@loveruby.net>
+
+	* net/loveruby/cflat/parser/Parser.jj: now NULL is not a reserved
+	  word.
+
+	* import/stddef.hb: define const NULL.
+
 Sat May 23 22:22:11 2009  Minero Aoki  <aamine@loveruby.net>
 
 	* net/loveruby/cflat/compiler/IRGenerator.java: refactoring:
diff --git a/import/stddef.hb b/import/stddef.hb
index fa0bd0d..4ae9a71 100644
--- a/import/stddef.hb
+++ b/import/stddef.hb
@@ -1,2 +1,5 @@
 // stddef.h
+
+const void* NULL = 0;
 typedef unsigned long size_t;
+typedef long ptrdiff_t;
diff --git a/import/stdio.hb b/import/stdio.hb
index f4e3681..fd0246b 100644
--- a/import/stdio.hb
+++ b/import/stdio.hb
@@ -1,7 +1,7 @@
 // #@@range/head{
 // stdio.hb
 
-import stddef;  // for size_t
+import stddef;  // for NULL and size_t
 import stdarg;
 
 typedef unsigned long FILE;   // dummy
diff --git a/net/loveruby/cflat/parser/Parser.jj b/net/loveruby/cflat/parser/Parser.jj
index 9b5b1c2..5b27446 100644
--- a/net/loveruby/cflat/parser/Parser.jj
+++ b/net/loveruby/cflat/parser/Parser.jj
@@ -324,7 +324,6 @@ TOKEN: {
     | <TYPEDEF  : "typedef">
     | <IMPORT   : "import">
     | <SIZEOF   : "sizeof">
-    | <NULL     : "NULL">
 }
 // #@@}
 
@@ -1331,11 +1330,6 @@ ExprNode primary():
         {
             return new VariableNode(location(t), t.image);
         }
-    | t=<NULL>
-        {
-            TypeRef ref = new PointerTypeRef(new VoidTypeRef());
-            return new IntegerLiteralNode(location(t), ref, 0);
-        }
     | "(" n=expr() ")"
         {
             return n;