public void TestDefine1()
        {
            TableTree tree = new TableTree();

            tree.Define("Foobar", "string_Const");
            Assert.IsTrue(tree.Lookup("Foobar").Unassigned);
        }
        public void TestLookup1()
        {
            TableTree tree = new TableTree();

            tree.Define("Foobar", "string_Const");
            tree.Bind("Foobar", "bar");
            Assert.IsFalse(tree.Lookup("Foobar").Unassigned);
            Assert.AreEqual(tree.Lookup("Foobar").GetValue(), "bar");
        }