public static SimpleOperatorType GetExpressionOperator(string str)
{
SimpleOperatorType Operator = SimpleOperatorType.Equal;
switch (str)
{
case "=":
Operator = SimpleOperatorType.Equal;
break;
case "<":
Operator = SimpleOperatorType.Lesser;
break;
case ">":
Operator = SimpleOperatorType.Greater;
break;
case "<=":
Operator = SimpleOperatorType.LesserEqual;
break;
case ">=":
Operator = SimpleOperatorType.GreaterEqual;
break;
default:
throw new Exception("Invalid Operator: " + str);
}
return(Operator);
}
/// <summary>
/// Create a SimpleExpression or a BooleanExpression based on the string that this method receive
/// </summary>
/// <param name="SimpleExpression"></param>
/// <returns></returns>
public static BooleanOperand Create(string ExpressionToEvaluate)
{
Regex re;
Match m;
re = new Regex(@"(?<exp1>.*)\s*(?<op>[&][&]|[|][|])\s*(?<exp2>.*)\s*");
m = re.Match(ExpressionToEvaluate);
if (m.Success) // complex expression ==> a=1 && b>4
{
// exp2 is a simple expression for sure
BooleanOperand exp2 = BooleanOperand.Create(m.Groups["exp2"].Value);
BooleanOperatorType Operator = BooleanExpression.GetBooleanOperator(m.Groups["op"].Value);
BooleanOperand exp1 = BooleanOperand.Create(m.Groups["exp1"].Value);
BooleanExpression be = new BooleanExpression(exp1, Operator, exp2);
return(be);
}
// At this point it's a simple expression
re = new Regex(@"(?:(?<left>\w+)\s*(?<op>[=]|[>]|[<]|[<][=]|[>][=])\s*(?<right>[\x22]?\w+[\x22]?))");
m = re.Match(ExpressionToEvaluate);
if (!m.Success)
{
throw new Exception("Invalid SimpleExpression: " + ExpressionToEvaluate);
}
string Property = m.Groups["left"].Value;
string Value = m.Groups["right"].Value;
SimpleOperatorType ExpressionOperator = SimpleExpression.GetExpressionOperator(m.Groups["op"].Value);
SimpleExpression simple = new SimpleExpression(Property, ExpressionOperator, Value);
return(simple);
}
public SimpleExpression(string Property, SimpleOperatorType Operator, object Value)
{
_Property = Property;
_Operator = Operator;
_Value = Value;
}
