[GDL2/base] RFC: NSControl classes

[David Ayers]

Hello,

OK, now let's get back to using the undocumented "NSControl" classes:
NSFault
NSFaultHandler
NSClassDescription
to be the superclasses of the coresponding EOClasses, i.e. ...

http://mail.gnu.org/archive/html/bug-gnustep/2003-04/msg00034.html

As NSClassDescription is the only documented class, it happens to be 
only class currently available from gnustep-base.

- I'm very unsure, whether we should support these classes in GDL2 at 
all, but I'm willing to try.  Manuel?
- If we support it, should we add the NSClasses to gnustep-base? Richard?
- Independent of where they would be added, should GDL2 always use the 
superclasses or should we try to configure GDL2 to use them explicitly 
and not use them by default?

My personal opinion is:
- GDL2 is trying to be WO45 compatible and these NSClasses do not exist 
in that scope.
- adding support for them will complicate the code.
- the NSClasses implementation can't use any of the 
GDL2Classes/features.  This can make the implementation rather awkward.
- GDL2 looses access to some of the cached information in the NSClasses 
(EO/NSClassDescription)

And most of all, I don't see any real merit in using NSClasses.  I 
acknowledge the fact that some might believe that running GDL2 on OS X 
makes them feel better when using as many Foundation classes as 
available.  But because we don't know what these classes really do and 
how the would fit into a GDL2 mechanics, I believe the opposite is true, 
because we loose control of what is going on.

So I would vote against adding these classes, but if overruled, I would 
volunteer to try to integrate them so they are as little invasive as 
possible.

In the (as I fear almost likely) case that in June Apple will present 
EOF 4 which makes use of these classes (and adds documentation in 
Foundation for these and possibly other classes), we may have to 
consider this again.  My vote would be leave GDL2 WO4.5 compatible and 
possibly start a new GDL3 library to be EOF current compatible.  
Personally I would probably focus on GDL2 rather than GDL3.  But I must 
admit that if gnustep-base tracked Cocoa once these classes are 
documented and used them internally, keeping GDL2 stable (once we get 
that far :-) ) with gnustep-base might be a daunting task.  Also 
explaining to users why gnustep-base uses 
NSClasses/Exceptions/Notification/OtherKeys and GDL2 uses the EOVersions 
and figureing out how to write code that supports both simultaniously, 
won't make it any eaiser.  But WO 4.5 compatibility is very important to 
me.  (And others porting WO4.5 projects.)

I think we should postpone any changes in that direction until the end 
of June and then rediscuss this.

Cheers,
Dave