private Expression DoEvalPostfixExpr(List<Result> results)
        {
            var suffixes = new List<PostfixOperator>();

            for (int i = 1; i < results.Count; ++i)
            {
                suffixes.Add((PostfixOperator) results[i].Value);
            }

            var identifier = new Identifier(results[0].Text);
            return new PostfixExpression(identifier, suffixes.ToArray());
        }
 public PostfixExpression(Identifier identifier, PostfixOperator[] suffixes)
 {
     m_identifier = identifier;
     m_suffixes = suffixes;
 }