On Mon, Mar 30, 2009 at 1:06 AM, Luke the Hiesterman <luket...@apple.com> wrote: > Up to this point, I've thought of properties as "syntactic sugar" for method > calls. That is myObject.size should compile the same as [myObject size] > unless of course a custom getter is set in the property declaration, then it > would compile the same as if I had called that getter. What makes me > question this is that there's apparently a need for dealing with properties > at the runtime level, as discussed in > http://developer.apple.com/DOCUMENTATION/Cocoa/Conceptual/ObjCRuntimeGuide/Articles/ocrtPropertyIntrospection.html > > I can't think of anything about properties that needs to be dealt with at > runtime. My understanding has it that all information necessary for what > properties do is available at compile time. E.g. the method to call, return > types, how to compile synthesized properties using copy, retain, assign, > nonatomic, and also whether to throw an error if something is readonly. So, > then, my question is, what about using properties requires a runtime > component? To me it feels like everything could be handled by the compiler.
I think what you're missing is that the runtime has a lot of information available through APIs that aren't strictly necessary at runtime. For example, you can get a list of method names and argument/return types, or a list of ivar names and types, even though none of this stuff is needed to send a message or access an ivar. This sort of metadata is provided just for the benefit of other code. For example, the method/ivar information is used by Cocoa to implement things like key/value coding. You can use it yourself for your own purposes. As far as I know, Cocoa doesn't use the property info for anything at the moment, but it's there just so that you can use it if you have a use for it. And one last note: don't mix up the dot syntax with properties. The API whose documentation you've linked to is about @property stuff. The dot syntax is just a funny way to message getters and setters. Other than the fact that the dot syntax is commonly used with getters and setters declared with @property, they are completely unrelated. Mike _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
