/// <summary>
/// Static version of the Expression Evaluator
/// </summary>
/// <param name="expression">expression to be evaluated</param>
/// <param name="handler">attach a custom function handler</param>
/// <returns></returns>
public static object Evaluate(string expression, AdditionalFunctionEventHandler handler)
{
ExpressionEval expr = new ExpressionEval(expression);
expr.AdditionalFunctionEventHandler += handler;
return(expr.Evaluate());
}
/// <summary>
/// Executes the function based upon the name of the function
/// </summary>
/// <param name="name">name of the function to execute</param>
/// <param name="p">parameter list</param>
/// <returns>returned value of executed function</returns>
//[SuppressMessage("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity")]
private object ExecuteFunction(string name, object[] p)
{
object[] parameters = null;
if (p != null)
{
parameters = (object[])p.Clone();
for (int x = 0; x < parameters.Length; x++)
{
if (parameters[x] is IExpression)
{
parameters[x] = ((IExpression)parameters[x]).Evaluate();
}
}
}
switch (name.ToLower(CultureInfo.CurrentCulture))
{
// Math functions
case "sin": return(Math.Sin(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "cos": return(Math.Cos(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "tan": return(Math.Tan(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "sec": return(1 / Math.Cos(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "csc": return(1 / Math.Sin(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "cot": return(1 / Math.Tan(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "asin": return(Math.Asin(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "acos": return(Math.Acos(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "atan": return(Math.Atan(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "sinh": return(Math.Sinh(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "cosh": return(Math.Cosh(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "tanh": return(Math.Tanh(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "abs": return(Math.Abs(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "sqrt": return(Math.Sqrt(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "ciel": return(Math.Ceiling(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "floor": return(Math.Floor(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "exp": return(Math.Exp(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "log10": return(Math.Log10(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "log": return((parameters.Length > 1) ?
Math.Log(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture), Convert.ToDouble(parameters[1], CultureInfo.CurrentCulture)) :
Math.Log(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
case "max": return(Math.Max(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture), Convert.ToDouble(parameters[1], CultureInfo.CurrentCulture)));
case "min": return(Math.Min(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture), Convert.ToDouble(parameters[1], CultureInfo.CurrentCulture)));
case "pow": return(Math.Pow(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture), Convert.ToDouble(parameters[1], CultureInfo.CurrentCulture)));
case "round": return((parameters.Length > 1) ?
Math.Round(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture), Convert.ToInt32(parameters[1], CultureInfo.CurrentCulture)) :
Math.Round(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture)));
//case "trunc": return Math.Truncate(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture));
case "e": return(Math.E);
case "pi": return(Math.PI);
//DateTime functions
case "now": return(DateTime.Now);
case "today": return(DateTime.Today);
case "mindate": return(DateTime.MinValue);
case "maxdate": return(DateTime.MaxValue);
case "monthname": return((new DateTime(2000, Convert.ToInt32(parameters[0]), 1)).ToString("MMMM"));
case "adddays": return(Convert.ToDateTime(parameters[0]).AddDays(Convert.ToInt32(parameters[1])));
case "addmonths": return(Convert.ToDateTime(parameters[0]).AddMonths(Convert.ToInt32(parameters[1])));
case "addyears": return(Convert.ToDateTime(parameters[0]).AddYears(Convert.ToInt32(parameters[1])));
case "addhours": return(Convert.ToDateTime(parameters[0]).AddHours(Convert.ToInt32(parameters[1])));
case "addminutes": return(Convert.ToDateTime(parameters[0]).AddMinutes(Convert.ToInt32(parameters[1])));
case "addseconds": return(Convert.ToDateTime(parameters[0]).AddSeconds(Convert.ToInt32(parameters[1])));
//Formatting Functions
case "fmtnum": return(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture).ToString("" + parameters[1], CultureInfo.CurrentCulture));
case "fmtdate": return(Convert.ToDateTime(parameters[0], CultureInfo.CurrentCulture).ToString("" + parameters[1], CultureInfo.CurrentCulture));
//Numerical Expression Evaluation
case "expr":
{
ExpressionEval eval = new ExpressionEval("" + parameters[0]);
eval.AdditionalFunctionEventHandler += this.AdditionalFunctionEventHandler;
eval._variables = this._variables;
return(eval.Evaluate());
}
//Casting Functions
case "cdbl": return(Convert.ToDouble(parameters[0], CultureInfo.CurrentCulture));
case "cint": return(Convert.ToInt32(parameters[0], CultureInfo.CurrentCulture));
case "clong": return(Convert.ToInt64(parameters[0], CultureInfo.CurrentCulture));
case "cuint": return(Convert.ToUInt32(parameters[0], CultureInfo.CurrentCulture));
case "culong": return(Convert.ToUInt64(parameters[0], CultureInfo.CurrentCulture));
case "cdatetime": return(Convert.ToDateTime(parameters[0], CultureInfo.CurrentCulture));
case "str": return(parameters[0].ToString());
//Logical Functions
case "iif": return(Iif(parameters));
case "case": return(Case(parameters));
//security fucntions
case "currentuserid": return(WindowsIdentity.GetCurrent().Name.ToLower());
default: return(AdditionalFunctionHelper(name, parameters));
}
}
/// <summary>
/// Static version of the Expression Evaluator
/// </summary>
/// <param name="expression">expression to be evaluated</param>
/// <returns></returns>
public static object Evaluate(string expressionString)
{
ExpressionEval expression = new ExpressionEval(expressionString);
return(expression.Evaluate());
}