/// <summary>
/// Calculates the specified expression.
/// 计算器，计算数学表达式的值
/// </summary>
/// <param name="expression"> 1+2+（1*3)</param>
/// <returns></returns>
public static string Calculate(string expression)
{
Token token = new Kooboo.Common.Dynamic.Calculator.Parser.Token(expression);
Evaluator evaluator = new Evaluator(token);
string value;
string errorMsg;
if (!evaluator.Evaluate(out value, out errorMsg))
{
throw new CalculateExpression(errorMsg);
}
return value;
}
private bool Eval(Parser.TokenItems Parameters, out Parser.TokenItem Result, out string ErrorMsg)
{
// initialize the outgoing variables
ErrorMsg = "";
Result = null;
// make sure we have at least 1 parameter
if (Parameters.Count != 1)
{
ErrorMsg = "Eval[] Operand Function requires 1 parameter.";
return false;
}
// get the expression to be evaluated
string expression = Support.DataTypeCheck.RemoveTextQuotes(Parameters[0].TokenName);
// create the tokens
Parser.Token tokens = new Parser.Token(expression);
if (tokens.AnyErrors == true)
{
ErrorMsg = tokens.LastErrorMessage;
return false;
}
// create the evaluator object
Evaluator e = new Evaluator(tokens);
string value = "";
if (e.Evaluate(out value, out ErrorMsg) == false) return false;
if (Support.DataTypeCheck.IsInteger(value) == true)
Result = new Parser.TokenItem(value, Parser.TokenType.Token_Operand, Parser.TokenDataType.Token_DataType_Int, false);
else if (Support.DataTypeCheck.IsDouble(value) == true)
Result = new Parser.TokenItem(value, Parser.TokenType.Token_Operand, Parser.TokenDataType.Token_DataType_Double, false);
else if (Support.DataTypeCheck.IsDate(value) == true)
Result = new Parser.TokenItem(value, Parser.TokenType.Token_Operand, Parser.TokenDataType.Token_DataType_Date, false);
else
Result = new Parser.TokenItem(value, Parser.TokenType.Token_Operand, Parser.TokenDataType.Token_DataType_String, false);
return true;
}