/// <summary>
/// 将表达式中的操作数和运算符分割出来
/// </summary>
/// <param name="expression">文本表达式</param>
/// <returns>操作数与运算符表</returns>
internal static List <IOperatorOrOperand> SplitExpression(string expression)
{
List <IOperatorOrOperand> output = new List <IOperatorOrOperand>();
StringBuilder operandbuf = new StringBuilder();
StringBuilder operatorbuf = new StringBuilder();
// 记录刚才最后输出的表达式项
IOperatorOrOperand lastItem = null;
// 在尾部添加一个空格，帮助分离最后一个操作数或运算符
expression = expression + " ";
double result = 0;
for (int i = 0; i < expression.Length; i++)
{
if (char.IsDigit(expression[i]) == true || expression[i] == '.')
{
// 如果是数字或小数点（操作数成份）
// 结束前一个运算符
if (operatorbuf.Length > 0)
{
// 尝试获取运算符
OperatorBase opr = TryGetOperator(operatorbuf.ToString(), lastItem);
if (opr != null)
{
output.Add(opr);
lastItem = opr;
operatorbuf.Length = 0;
}
else
{
throw new InvalidCastException(operatorbuf.ToString() + " 无法解析为合法的运算符。");
}
}
// 合并入当前操作数项
operandbuf.Append(expression[i]);
}
else
{
// 不是数字或小数点（运算符成份）
// 结束前一个操作数
if (operandbuf.Length > 0)
{
if (double.TryParse(operandbuf.ToString(), out result) == false)
{
throw new FormatException(operandbuf.ToString() + " 无法解析为合法的操作数。");
}
// 输出操作数
OperandInfo operand = new OperandInfo(double.Parse(operandbuf.ToString()));
output.Add(operand);
lastItem = operand;
operandbuf.Length = 0;
}
// 合并非空白字符到当前运算符项
if (char.IsWhiteSpace(expression[i]) == false)
{
operatorbuf.Append(expression[i]);
}
// 分析并输出运算符
if (operatorbuf.Length > 0)
{
// 尝试获取运算符
OperatorBase opr = TryGetOperator(operatorbuf.ToString(), lastItem);
if (opr != null)
{
output.Add(opr);
lastItem = opr;
operatorbuf.Length = 0;
}
}
}
}
return(output);
}
public Operand(string operandString)
{
m_OperandString = operandString;
Info = new OperandInfo(operandString);
State = OperandState.Init;
}
/// <summary>
/// �����ʽ�еIJ�������������ָ����
/// </summary>
/// <param name="expression">�ı����ʽ</param>
/// <returns>���������������</returns>
internal static List<IOperatorOrOperand> SplitExpression(string expression)
{
List<IOperatorOrOperand> output = new List<IOperatorOrOperand>();
StringBuilder operandbuf = new StringBuilder();
StringBuilder operatorbuf = new StringBuilder();
// ��¼�ղ��������ı��ʽ��
IOperatorOrOperand lastItem = null;
// ��β�����һ���ո����������һ���������������
expression = expression + " ";
double result = 0;
for (int i = 0; i < expression.Length; i++)
{
if (char.IsDigit(expression[i]) == true || expression[i] == '.')
{
// ��������ֻ�С���㣨�������ɷݣ�
// ����ǰһ�������
if (operatorbuf.Length > 0)
{
// ���Ի�ȡ�����
OperatorBase opr = TryGetOperator(operatorbuf.ToString(), lastItem);
if (opr != null)
{
output.Add(opr);
lastItem = opr;
operatorbuf.Length = 0;
}
else
{
throw new InvalidCastException(operatorbuf.ToString() + " ������Ϊ�Ϸ����������");
}
}
// �ϲ��뵱ǰ��������
operandbuf.Append(expression[i]);
}
else
{
// �������ֻ�С���㣨������ɷݣ�
// ����ǰһ��������
if (operandbuf.Length > 0)
{
if (double.TryParse(operandbuf.ToString(), out result) == false)
{
throw new FormatException(operandbuf.ToString() + " ������Ϊ�Ϸ��IJ�������");
}
// ���������
OperandInfo operand = new OperandInfo(double.Parse(operandbuf.ToString()));
output.Add(operand);
lastItem = operand;
operandbuf.Length = 0;
}
// �ϲ��ǿհ��ַ�����ǰ�������
if(char.IsWhiteSpace(expression[i]) == false)
{
operatorbuf.Append(expression[i]);
}
// ��������������
if (operatorbuf.Length > 0)
{
// ���Ի�ȡ�����
OperatorBase opr = TryGetOperator(operatorbuf.ToString(), lastItem);
if (opr != null)
{
output.Add(opr);
lastItem = opr;
operatorbuf.Length = 0;
}
}
}
}
return output;
}
