/// <summary>
/// 根据函数名获取函数
/// </summary>
/// <param name="fName"></param>
/// <returns></returns>
public static DelExpressFunctionHandle GetHandle(string fName)
{
DelExpressFunctionHandle ret = null;
dicHandle.TryGetValue(fName, out ret);
return(ret);
}
/// <summary>
/// 计算表达式的值
/// </summary>
/// <returns></returns>
private double Eval()
{
LinkedList <double> stkNumber = new LinkedList <double>(); //数字
LinkedList <char> stkSymbol = new LinkedList <char>(); //运算符
StringBuilder tmpNumber = new StringBuilder();
while (strEnum.MoveNext())
{
char cur = strEnum.Current;
if (cur == '(') //如果是左括号就开始算表达式
{
stkChr.Push(')');
double num = 0;
if (tmpNumber.Length > 0)
{
DelExpressFunctionHandle handle = ExpressFunctions.GetHandle(tmpNumber.ToString().ToLower());
if (handle == null)
{
throw new Exception("找不到函数" + tmpNumber.ToString());
}
List <double> lstParams = new List <double>();
while (stkChr.Count > 0 && stkChr.Peek() == ')')
{
lstParams.Add(Eval());
}
num = handle(lstParams.ToArray());
tmpNumber.Remove(0, tmpNumber.Length);
}
else
{
num = Eval();
}
stkNumber.AddLast(num);
}
else if (cur == ',')
{
if (stkChr.Count < 0)
{
throw new Exception("表达式错误");
}
break;
}
else if (cur == ')')//表达式结束，跳出循环
{
if (stkChr.Count < 0)
{
throw new Exception("表达式错误");
}
stkChr.Pop();
break;
}
else
{
//if (IsNumber(cur))//如果是数组就加到临时数字字符串
//{
// tmpNumber.Append(cur);
// continue;
//}
//else
if (IsOperators(cur)) //如果是符号
{
stkSymbol.AddLast(cur); //加到符号列表
if (tmpNumber.Length > 0)
{
stkNumber.AddLast(GetNumber(tmpNumber)); //加到数字列表
tmpNumber.Remove(0, tmpNumber.Length); //清空临时数字字符串
}
}
else
{
tmpNumber.Append(cur);
continue;
}
}
}
if (tmpNumber.Length > 0)
{
stkNumber.AddLast(GetNumber(tmpNumber));//加到数字列表
}
return(Calculation(stkNumber, stkSymbol));
}
