Angry citizen stikes once again. forward references problems

[Derek Parnell]

On Sun, 30 Jul 2006 18:57:14 -0400, Jarrett Billingsley wrote:

> "Derek" <derek at psyc.ward> wrote in message 
> news:zbzgquaqpewl$.brpiyqr0sclz.dlg at 40tude.net...
>> I don't understand this Dawid. It seems you are trying to use a nested
>> class inside another class, and I'm sure you can't and shouldn't do that.
> 
> Why not?  What about a parent "factory" class, which needs to create 
> instances of a nested class, which the user can use?  The nested class can 
> still access its outer class, and the user can use the nested class 
> instances just fine.
> 
>> I thought the purpose of nested classes was to restrict the scope of the
>> nested class to its parent and thus trying to use it outside of the parent
>> doesn't seem right to me.
> 
> Sometimes that's true.  Sometimes you just want the nested class to have 
> access to the outer class.  Granted, you can do this with friend classes, 
> but.. as mentioned above, if you want an "owner/owned" relationship between 
> the classes, using a nested class seems somewhat more elegant.

Okay ... but why would you want a nested class to be used as a type inside
another class? Seems like a silly thing to do. What's the advantage of
doing that?

>> D won't let you do even the more simple case ...
>>
>> //------- test3.d -----
>> class X
>> {
>>  static class NX
>>  {
>>  }
>> }
>>
>> class Y
>> {
>>     NX q; // test3.d(10): identifier 'NX' is not defined
>> }
>> // -------------------- //
>>
>> I think dmd is working correctly, though the error messages are not 
>> exactly
>> helpful.
> 
> Namespaces, namespaces.
> 
> Class Y
> {
>     X.NX q;
> }
> 
> And you could even "alias X.NX NX;" if you wanted to.

Seems wrong to me. I can't see why one would bother making obscure,
hard-to-maintain, hard-to-read classes definitions using this technique.
Seems counter-productive.
 

-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
"Down with mediocrity!"
31/07/2006 9:46:30 AM