Re: Use of Mac OS X 10.5 / Leopards Garbage Collection Considered Harmful

FROM : glenn andreas
DATE : Wed Feb 06 16:45:43 2008

On Feb 6, 2008, at 3:39 AM, John Engelhart wrote:

>
> On Feb 5, 2008, at 7:40 AM, Alastair Houghton wrote:
>

>> On 5 Feb 2008, at 00:14, John Engelhart wrote:
>>

>>> I had such high hopes for Cocoa's GC system because once you're 
>>> spoiled by GC, it's hard to go back.
>>>
>>> Unfortunately, the 4-5 months of time I've put in on Leopard's GC 
>>> system has not been nearly as pleasant.  It has been outright 
>>> frustrating, and it's reached the point where I consider the 
>>> system untenable.

>>
>> Honestly, this point has now been answered over and over.
>>
>> I think it comes down to the fact that you have failed to 
>> appreciate that Cocoa GC is designed for easy use with *OBJECTS*. 
>> If you're using it with objects, it "just works".

>
> You misunderstand what Objective C is, and how it works.  "Objects" 
> is synonymous for "Structs".




If that were true, you'd be able to declare objects as local variables 
(as opposed to as pointers to structures):

   NSPoint aPoint; // <-- NSPoint = struct, legal
   NSString aString; // <-- NSString = object, Illegal

(yes, at one time there was an attempt to add support for that, but it 
didn't survive).

Structures don't have "magic invisible members":

@interface Foo {
}
@end

Foo *aFoo;
NSLog(@"Foo is a %@", aFoo->isa);

Notice how there is an "isa" member that is automatically put there, 
not unlike the way that a C++ object might have a vtable (or other 
internal plumbing for multiple inheritance).




Glenn Andreas                      <email_removed>
  <http://www.gandreas.com/> wicked fun!
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