AjErl.Language.List.FirstVariable C# (CSharp) Method

        public Variable FirstVariable()
        {
            Variable result = null;

            if (this.head is IElement)
            {
                result = ((IElement)this.head).FirstVariable();
                if (result != null)
                    return result;
            }

            if (this.tail is IElement)
                result = ((IElement)this.tail).FirstVariable();

            return result;
        }

        public void FirstVariable()
        {
            List list = new List(new Variable("H"), new Variable("T"));
            var result = list.FirstVariable();

            Assert.IsNotNull(result);
            Assert.AreEqual("H", result.Name);
        }