Re: fyi - Mac OS native GDL2 / GSWeb Installer package

[Tim McIntosh]

Hi David,

On Mar 6, 2008, at 7:54 AM, David Ayers wrote:

> Tim McIntosh schrieb:
>
> > I have made a number of minor changes that I eventually intend to  
> > either
> > undo or get accepted into the mainline.  One difference in this  
> > version
> > that may never make it into the mainline is the use of Cocoa-style
> > (native) KVC (as opposed to WO-4.5 style), which I wanted for use  
> > with
> > the WO5 app that I'm porting.
>
> It depends on how well we can emulate compatibility.  Currently
> GSWeb/GDL2 is used for Projects that are currently still deployed as
> GNUstep based and WO45 based applications.
>
> So it's very important not to break WO45 compatibility.  Yet if we can
> emulate it in a similar way as -base is currently trying, then I'd  
> take
> the patches as long as they don't show issues.

Sounds good.

> Do you really need to change the internal KVC?  Maybe we just need to
> implement a few more legacy methods in EOKeyValueCoding.m to get it  
> work
> on OS X.  (And avoid some warnings from -base while we are at it.)

I think I was being too vague with regard to KVC.  I wasn't referring  
to the deprecated KVC methods issue that has been discussed on the  
list recently, but something much more trivial.  All I was talking  
about was the difference in behavior of -[NSDictionary valueForKey:]  
and -[NSDictionary storedValueForKey:] with respect to "special  
keys" (GDL2's @"allKeys" vs. Cocoa's @"@allKeys"),  and the different  
handling of NSArray aggregate functions when there is a key path  
following the aggregating operator instead of a simple key.

For example:   address@hidden@count

With Cocoa's -[NSArray valueForKeyPath:] behavior, this would invoke  
[object valueForKeyPath: @"address@hidden"] on each object in the  
display group, then return the sum of the counts.

With GDL2's behavior, this would attempt to invoke [[object  
valueForKey: @"itemsArray"] decimalValue] on each object in the  
display group, sum the results, and then invoke [result valueForKey:  
@"@count"] on the sum--none of which would actually work as intended  
in this case.

My KVC changes are really pretty simple/naive (see attached patch).  I  
was assuming this was an EOF vs. Cocoa behavior difference, but I'm  
not really sure about that.  The old EOF documentation that I looked  
at didn't seem to be clear on what the behavior should be in this  
case, and I didn't have a setup where I could test EOF to see what it  
does, compared to GDL2.  I don't have a high degree of confidence that  
I'm doing "the right thing" here, but I was trying to get a specific  
application working without changing any of its logic, and this seemed  
to do the trick.

Thanks for your help,
Tim

EOKeyValueCoding.m.diff
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