--- a/Jint.Runtime/VM/Box.cs	Sun Oct 27 17:23:25 2013 +0400
+++ b/Jint.Runtime/VM/Box.cs	Sun Oct 27 21:20:59 2013 +0400
@@ -5,13 +5,13 @@
 using Jint.Runtime.VM.OpCodes;
 
 namespace Jint.Runtime.VM {
-    class Box<T>: IBox, IGettter<T>, ISetter<T> {
+    class Box<T>: AbstractBox, IGettter<T>, ISetter<T> {
 
         public T holdingValue;
         object[] m_impl;
         RuntimeContext m_runtime;
 
-        public Box(T value, RuntimeContext runtime) {
+        public Box(T value, RuntimeContext runtime): base(typeof(T)) {
             if (runtime == null)
                 throw new ArgumentNullException("runtime");
 
@@ -19,7 +19,7 @@
             m_runtime = runtime;
         }
 
-        public object[] Impl {
+        object[] Impl {
             get {
                 if (m_impl == null)
                     m_impl = m_runtime.GetImpl(typeof(T));
@@ -27,15 +27,6 @@
             }
         }
 
-        public Type HoldingType {
-            get { return typeof(T); }
-        }
-
-        public void InvokeBinaryOperation(Codes code, int arg2, int dest, Frame frame) {
-            var op = (BinaryOperation<T>)Impl[(int)code];
-            frame.SetValue(dest, op(holdingValue, frame.GetValue<T>(arg2)));
-        }
-
         public T Get() {
             return holdingValue;
         }
@@ -43,5 +34,25 @@
         public void Set(T value) {
             holdingValue = value;
         }
+
+        public override void InvokeBinaryOperation(Codes code, int arg2, int dest, Frame frame) {
+            var op = (BinaryOperation<T>)Impl[(int)code];
+            frame.SetValue(dest, op(holdingValue, frame.GetValue<T>(arg2)));
+        }
+
+        public override void InvokeUnaryOperation(Codes code, int dest, Frame frame) {
+            var op = (UnaryOperation<T>)Impl[(int)code];
+            frame.SetValue(dest, op(holdingValue));
+        }
+
+        public override void InvokeCompareOperation(int arg2, int dest, Frame frame) {
+            var op = (CompareOperation<T>)Impl[(int)Codes.Cmp];
+            frame.SetValue(dest, op(holdingValue, frame.GetValue<T>(arg2)));
+        }
+
+        public override void InvokeEqualityOperation(int arg2, int dest, Frame frame) {
+            var op = (EqualityOperation<T>)Impl[(int)Codes.Cmp];
+            frame.SetValue(dest, op(holdingValue, frame.GetValue<T>(arg2)));
+        }
     }
 }