private Stack <IExpression> opStack = new Stack <IExpression>(); //堆栈
//解析表达式，返回后缀表达式
private bool Parse(string text)
{
string expression = text.Trim();
string literal = string.Empty; //变量/常数/函数名等
IExpression op = null; //操作符
bool isStringToken = false;
int pos = 0;
while (pos < expression.Length)
{
isStringToken = false;
string token = GetToken(expression, ref pos, ref isStringToken);
if (RegsitryManager.ISOperator(token))
{
InsertPostfixExpression(new OperatorExprssion(token));
}
else if (RegsitryManager.IsFunction(token))
{
//函数其实是一种特殊的运算符
InsertPostfixExpression(new FuncExpression(token));
}
else
{
//值
postExpression.Add(new VariableExpression(token, isStringToken));
}
}
//AddPostExpressionLiteral();
//最后stack中的所有数据弹出加入到对应中
while (opStack.Count > 0)
{
op = opStack.Pop();
if (op.Identity == RegsitryManager.TOKEN_LEFT)
{
//括号不匹配
throw new AddinException(text + "Expression invalid!");
}
else
{
postExpression.Add(op);
}
}
//去掉逗号运算符
postExpression.RemoveAll(item => item.Identity == RegsitryManager.TOKEN_COMMA);
return(true);
}
public static OperatorType OpType(string text)
{
if (text == RegsitryManager.TOKEN_LEFT)
{
return(OperatorType.LEFT);
}
if (text == RegsitryManager.TOKEN_RIGHT)
{
return(OperatorType.RIGHT);
}
if (text == RegsitryManager.TOKEN_ADD)
{
return(OperatorType.ADD);
}
if (text == RegsitryManager.TOKEN_SUB)
{
return(OperatorType.SUB);
}
if (text == RegsitryManager.TOKEN_MUL)
{
return(OperatorType.MUL);
}
if (text == RegsitryManager.TOKEN_DIV)
{
return(OperatorType.DIV);
}
if (text == RegsitryManager.TOKEN_AND)
{
return(OperatorType.AND);
}
if (text == RegsitryManager.TOKEN_OR)
{
return(OperatorType.OR);
}
if (text == RegsitryManager.TOKEN_LT)
{
return(OperatorType.LT);
}
if (text == RegsitryManager.TOKEN_GT)
{
return(OperatorType.GT);
}
if (text == RegsitryManager.TOKEN_LE)
{
return(OperatorType.LE);
}
if (text == RegsitryManager.TOKEN_GE)
{
return(OperatorType.GE);
}
if (text == RegsitryManager.TOKEN_ET)
{
return(OperatorType.ET);
}
if (text == RegsitryManager.TOKEN_UT)
{
return(OperatorType.UT);
}
//返回函数
if (RegsitryManager.IsFunction(text))
{
return(OperatorType.FUNC);
}
return(OperatorType.ERR);
}
