private void _read()
            {
                _code = m_io.ReadU1();
                switch (Code)
                {
                case 73: {
                    _body = new Intval(m_io, this, m_root);
                    break;
                }

                case 83: {
                    _body = new Strval(m_io, this, m_root);
                    break;
                }

                default: {
                    _body = new Noneval(m_io, this, m_root);
                    break;
                }
                }
            }
            private void _read()
            {
                _code = System.Text.Encoding.GetEncoding("ASCII").GetString(m_io.ReadBytes(1));
                switch (Code)
                {
                case "I": {
                    _body = new Intval(m_io, this, m_root);
                    break;
                }

                case "S": {
                    _body = new Strval(m_io, this, m_root);
                    break;
                }

                default: {
                    _body = new Noneval(m_io, this, m_root);
                    break;
                }
                }
            }