I would like to add some functions to double type. I created new class "ExtraDouble" and I I want to class behave as double. 

For example: I have:

```
class ExtraDouble{
double myVar = 0.59;
}

```

And, wherever: 

```
Extradouble e = new Extradouble();
String.Format("Value of e is: {0}", e) // return: Value of e is: 0.59

```

Is it possible? 

Default using "e" must return value of variable "myVar" (without any accessors)