@@ -51,12 +51,12 @@
 	mixin SimpleToHash;
 }
 
 ///
-class UndefinedValue : Value
+class BottomValue : Value
 {
 	mixin SimpleConstructor;
-	override string toString() const { return "<undefined>"; }
+	override string toString() const { return "_|_"; }
 	override int opCmp(Object rhs) {
 		if(auto r = cast(StrValue)rhs) return 0;
 		if(auto r = cast(Value)rhs)    return typeid(this).opCmp(typeid(r));
 		throw genex!RuntimeException("comparison with value and somithing other");