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Key-value observing


From: Stefan Urbanek
Subject: Key-value observing
Date: Wed, 2 Mar 2005 13:50:39 +0100
User-agent: Internet Messaging Program (IMP) 3.2.2

Hi,

Is anyone working on the Key-value observing?

http://developer.apple.com/documentation/Cocoa/Conceptual/KeyValueObserving/index.html

In the documentation one can read:

"Automatic key-value observing is implemented using a technique called
isa-swizzling. 

The isa pointer, as the name suggests, points to the object's class which
maintains a dispatch table. This dispatch table essentially contains pointers
to the methods the class implements, among other data. 

When an observer is registered for an attribute of an object the isa pointer of
the observed object is modified, pointing to an intermediate class rather than
at the true class. As a result the value of the isa pointer does not
necessarily reflect the actual class of the instance. 
"

Is it difficult to implement it in GNUstep? If not, what is needed?

If noone is working on it and if someone skilled knows how to implement it or
has some hints, please write notes for others here:

http://mediawiki.gnustep.org/index.php?title=Key_Value_Observing&action=edit

Thanks,

Stefan Urbanek
--
http://stefan.agentfarms.net

First they ignore you, then they laugh at you, then they fight you, then
you win.
- Mahatma Gandhi




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