On 23 Sep 2016, at 00:45, Gabriel Zachmann <z...@tu-clausthal.de> wrote: >> Because the observer is an object. Your observation and a superclass >> observation come from the same object. Whether these are to be treated as >> different observations** cannot be determined automatically, hence the need >> for a “context”. > > Sure, but an observation method is what would be called a "callback" in plain > C. > In C, I can have many different callbacks. > I don't see why that should not be possible in Obj-C - I just would need a > mechanism to add tell the system the names / function pointers to be > registered as observers. > > Anyways, the concept of a block gets closer to what I mean, except it is > still not a named function/method.
The problem is that KVO was designed (probably because it avoids the overhead of an NSInvocation, as the observeValueForKeyPath method can't be called using performSelector) to funnel all its callbacks through a single method on your object. If it allowed specifying a SEL to call, on the observer, you wouldn't need a context parameter. Cheers, -- Uli Kusterer "The Witnesses of TeachText are everywhere..." http://www.zathras.de _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
