public bool PrepareArithmeticExpression(ArithmeticExpression expr)
        {
            bool res = (expr != null) && !string.IsNullOrWhiteSpace(mExpression);

            if (res)
            {
                expr.Variables  = mVariables;
                expr.Expression = mExpression;
            }
            return(res);
        }
 private void Parse()
 {
     mVariables.Clear();
     mExpression = "";
     if (!string.IsNullOrWhiteSpace(mInputString))
     {
         string[] a = mInputString.Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
         foreach (string s in a)
         {
             if (s.Contains("="))
             {
                 string[] ve = s.Split(new char[] { '=' }, StringSplitOptions.RemoveEmptyEntries);
                 if (ve.Length >= 2)
                 {
                     mVariables.Add(ve[0].Trim(), ArithmeticExpression.GetValue(ve[1].Trim()));
                 }
             }
             else
             {
                 mExpression = s.Trim();
             }
         }
     }
 }