On Aug 12, 2011, at 06:57 PM, Quincey Morris wrote:

> On Aug 12, 2011, at 04:08 , Martin Hewitson wrote:
> 
>> In an app I have a core data model which has a File entity which has a 
>> boolean attribute isText. This attribute is declared in the corresponding 
>> NSManagedObject subclass interface as
>> 
>> @property (assign) BOOL isText;
>> 
>> and in the implementation I do
>> 
>> @dynamic isText;
>> 
>> In Lion, accessing this with 
>> 
>> [file isText] 
>> 
>> works fine. But it doesn't work on Snow Leopard. There I have to do
>> 
>> [[file valueForKey:@"isText"] boolValue]
>> 
>> Is this expected behaviour? Was/is something broken on SL that was fixed on 
>> Lion? Or is it now broken on Lion? 
> 
> Yes. No. No.
> 
> It's new on Lion that the internal property accessors referenced by @dynamic 
> support scalar types directly. In the past, if you wanted the type of 
> property "isText" to BOOL rather than NSNumber, you had to write a custom 
> getter and setter to make it so.

OK, that explains the observations. I didn't know about this new behaviour on 
Lion.

> 
> For as long as you need to support 10.6 and earlier, I think you'll have to 
> supply the old-style custom implementations.
> 
> I don't think I watched the 2011 WWDC video on Core Data, but it's possible 
> this issue is discussed in there, and there may be a more elegant workaround.

I've watched that one and I don't recall this being mentioned, but I'll look 
back through it because perhaps it just didn't register the first time through.

Thanks for the information!

Martin

> 
> 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Martin Hewitson
Albert-Einstein-Institut
Max-Planck-Institut fuer 
    Gravitationsphysik und Universitaet Hannover
Callinstr. 38, 30167 Hannover, Germany
Tel: +49-511-762-17121, Fax: +49-511-762-5861
E-Mail: martin.hewit...@aei.mpg.de
WWW: http://www.aei.mpg.de/~hewitson
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~





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