public void AddUnaryOperation(IUnaryOperation operation)
{
if (!UnaryOperations.Contains(operation))
{
UnaryOperations.Add(operation);
}
}
/// <summary>
/// Generate the operation expression
/// </summary>
/// <typeparam name="T">Type of the values to apply operation on</typeparam>
/// <param name="member">Member to apply operation on</param>
/// <param name="targetValues">Values to apply operation on</param>
/// <returns>Operation expression</returns>
public Expression GetExpression <T>(Expression member, List <T> targetValues)
{
var type = member.Type;
// check if the member is a method call
if (IsMethodCall)
{
// get method by name
var method = type.GetMethod(MethodName);
if (method == null)
{
throw new Exception($"There is no method named {this} in the type {type.Name}");
}
// get parameters list
var parameters = method.GetParameters().ToList();
// check if values match parameters count
if (parameters.Count != targetValues.Count)
{
throw new Exception($"There is no method named {this} in the type {type.Name} taking the same count of input");
}
// convert values to a list of ConstantExpressions
var constants = parameters.Select(p => Expression.Constant(Convert.ChangeType(targetValues[parameters.IndexOf(p)], p.ParameterType))).ToList();
// generate a MethodCallExpression
return(Expression.Call(member, method, constants));
}
// if not a method call
// then validate that the member type is one of the predefined operations
if (Enum.TryParse(Type.ToString(), out ExpressionType expressionType))
{
// check if it is in the binary operations
if (BinaryOperations.Contains(Type))
{
// convert value to ConstantExpression
var constant = Expression.Constant(Convert.ChangeType(targetValues[0], type));
// generate a BinaryExpression
return(Expression.MakeBinary(expressionType, member, constant));
}
else if (UnaryOperations.Contains(Type))
{
// generate a UnaryExpression
return(Expression.MakeUnary(expressionType, member, typeof(bool)));
}
}
// throw an exception if operation not found
throw new Exception("Unknown Operation");
}
