Access modifier for extensions

[Gary Willoughby]

On Thursday, 16 January 2014 at 17:45:40 UTC, Boyd wrote:
> On Thursday, 16 January 2014 at 11:18:07 UTC, Gary Willoughby 
> wrote:
>> This can be achieved with traditional OOP design patterns and 
>> i have to agree with the above poster this is too much like 
>> C++ hacking and looks horrible.
>
> I think I misrepresented my case by mucking up the example. I 
> don't care about any individual use case. Ignore it. What I'm 
> looking for is a way to represent this:
>
> class AThing
> {
>     public void DoSomethingAnyoneCanDo();
>     public_ish void DoSomethingThatRequiresExpertise();
> }
>
> The first method in the class, is something you want to expose 
> to any user. The second is meant for the guy who wants access 
> to the more advanced stuff, where you have to know what you are 
> doing. Inheriting from the class is not an option, or at least 
> unwanted.
>
> Basically I need the 'package' attribute, but for modules 
> outside the package, even modules I have no control over, or 
> know anything about.
>
> Am I really the only who ever found the need for such a thing? 
> Because I see situations where this could be pretty damn handy, 
> all the time.

By your example i'm getting the impression you want a standard 
interface for users of your class but want advanced behaviour of 
the same interface for other users while avoiding inheritance? If 
this is the case, your answer is delegation[1].

class A
{
     private Delegate delegateObject;

     public void setDelegate(Delegate delegateObject)
     {
         this.delegateObject = delegateObject;
     }

     public value doSomethingAnyoneCanDo()
     {
         if (this.delegateObject)
         {
             return 
this.delegateObject.doSomethingThatRequiresExpertise();
         }

         // Do something anyone can do.
     }
}

[1]: http://en.wikipedia.org/wiki/Delegation_pattern

P.S. Don't confuse this with the D 'delegate' type.