public abstract void Visit(BinaryExpresssion expression);
public override void Visit(BinaryExpresssion expression)
{
// Evaluates the left expression and saves the value
expression.LeftExpression.Accept(this);
object left = result;
// Evaluates the right expression and saves the value
expression.RightExpression.Accept(this);
object right = result;
switch (expression.Type)
{
case BinaryExpressionType.And:
result = Convert.ToBoolean(left) && Convert.ToBoolean(right);
break;
case BinaryExpressionType.Or:
result = Convert.ToBoolean(left) || Convert.ToBoolean(right);
break;
case BinaryExpressionType.Div:
result = Convert.ToDecimal(left) / Convert.ToDecimal(right);
break;
case BinaryExpressionType.Equal:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) == 0;
break;
case BinaryExpressionType.Greater:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) > 0;
break;
case BinaryExpressionType.GreaterOrEqual:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) >= 0;
break;
case BinaryExpressionType.Lesser:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) < 0;
break;
case BinaryExpressionType.LesserOrEqual:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) <= 0;
break;
case BinaryExpressionType.Minus:
result = Convert.ToDecimal(left) - Convert.ToDecimal(right);
break;
case BinaryExpressionType.Modulo:
result = Convert.ToDecimal(left) % Convert.ToDecimal(right);
break;
case BinaryExpressionType.NotEqual:
// Use the type of the left operand to make the comparison
result = Comparer.Default.Compare(left,
Convert.ChangeType(right, left.GetType())) != 0;
break;
case BinaryExpressionType.Plus:
result = Convert.ToDecimal(left) + Convert.ToDecimal(right);
break;
case BinaryExpressionType.Times:
result = Convert.ToDecimal(left) * Convert.ToDecimal(right);
break;
case BinaryExpressionType.Pow:
result = Math.Pow(Convert.ToDouble(left), Convert.ToDouble(right));
break;
}
}
