Hi all,

i just played around a little with the c# operator overloading features
and an idea came to my mind. You all possibly know the Nullable<T>
Datatype. Now i thought it would be a nice idea to write my own
Revertable<T> type that maintains the values of multiple assignments and
can revert to a previous value. An Example to make it clear :

Revertable<int> ir0 = 123;
ir0 = 500;
ir0 = 700;
ir0.Revert(2)
int x = ir0;

now x should be equal to 123

This stuff could be used in some kind of simplified in-memory
transactions to help maintain state consitency.

I started up and wrote something like this :

  public class Revertable<T>
        {
            private List<T> valueList = new List<T>();

            private Revertable(T value)
            {
                valueList.Add(value);
            }

            private T Current
            {
                get
                {
                    return valueList[valueList.Count - 1];
                }
            }

       public void Revert(int times)
        {
            ...
        }

            public static implicit operator Revertable<T>(T value)
            {
                return new Revertable<T>(value);
            }

            public static implicit operator T(Revertable<T> value)
            {
                return value.Current;
            }
        }

Now the problem is, that the implicit conversion operator creates a
new instance of Revertable<T> when an assignment happens. So the
previously assigned value is lost :

Revertable<int> i = 10;
i = 11; // now i is a new instance of Revertable<int> and the previously
      assigned value is lost

Is there a way to convert to a given instance, instead of creating a new
one ?  I saw that it is impossible to overload the assignment operator
in c# . I know that i could easily add an Assign(T value) method to my
revertable class but that would make the code much less readable.

Perhaps i have to take another path and take a language that supports
custom assignment operator if one exists ?!

Thanks in advance for your ideas and suggestions

Philipp