obsolete method and behavior adding

[Markus Hitter]

Hello all,


here's a issue, I'm not too sure about.

In NSArray.m I see:

@implementation NSArray
...
+ (id) allocWithZone: (NSZone*)z {
  if (self == NSArrayClass) {
...
    } else {  // != NSArrayClass, e.g. GSArrayClass
      return NSAllocateObject(self, 0, z);
    }
}


In GSArray.m, something similar:

@interface GSArray : NSArray
...

@implementation GSArray
...
+ (id) allocWithZone: (NSZone*)zone
{
  GSArray       *array = NSAllocateObject(self, 0, zone);

  return array;
}


To all of my knowledge, the first implementation makes the 
second obsolete?



The reason I came across such an issue is, on NeXT runtime 
behavior_class_add_class() makes major trouble. A possible 
conclusion might be, we have to get rid of behavior adding on 
NeXT runtime, at least in +initialize methods.

In all occurences of behavior_class_add_class(), some GS* class 
is involved. I'm trying to find out why all these GS* classes 
exist.

Is it OK to consider behavior adding as some sort of multiple 
inheritance trough the backdoor?


Cheers,
Markus

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Dipl. Ing. Markus Hitter
http://www.jump-ing.de/