How to define opCast from native types

[Cheery]

> The line above is an explicit object construction. That's why D 
> allows that syntax. Unlike C++, there is no implicit conversion 
> when passing to a function:
>
> void func(Integer i)
> {}
>
>   func(1L);  // Does not call the constructor
>

Ali

Sorry for not being clear in my first port. I was not referring 
to implicit vs explicit conversion. I would also like to avoid 
explicit call to constructors.

For example I would like to avoid.

long ll;
Integer foo = ll;

But I want something like this to be enabled.

long ll;
Integer foo = cast(foo) ll;

Unfortunately for casting of native types, D seems to rely only 
on constructor functions.

Regards
- Cherry