public static GATNode _additiveExpression(this LL1Processor ll1)
        {
            var node = new GATNode();

            node.generator = AdditiveExpression;
            var term1 = ll1._term();

            node.AddChild(term1);
            var next = WordContainer.GetWordType();

            while (next == WordType.ADDOP)
            {
                var addop = WordContainer.Advance(WordType.ADDOP);
                node.AddChild(addop);
                var term2 = ll1._term();
                node.AddChild(term2);
                next = WordContainer.GetWordType();
            }
            return(node);
        }