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Re: Another Gnarly Objective-C Question!
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Re: Another Gnarly Objective-C Question!


  • Subject: Re: Another Gnarly Objective-C Question!
  • From: Dave <email@hidden>
  • Date: Wed, 13 Mar 2013 11:54:52 +0000


On 13 Mar 2013, at 09:13, Jean-Daniel Dupas wrote:


Le 13 mars 2013 à 01:55, Wim Lewis <email@hidden> a écrit :


On 12 Mar 2013, at 2:08 AM, Graham Cox wrote:
in a + method, [self class] === self. Once you've got that, you've got it.



You're overthinking this.

A class method is just an instance method of the class object. No magic at all. So all this confusion you've caused yourself about [super class] and so on is wholly unnecessary to correctly use class methods.

To be very slightly pedantic, the only magic here is 'super' --- sending a message to super (which you can only do from a method implementation) is special syntax that searches for the method starting with the implementation's class's superclass, rather than at the receiver's actual class. Everything else is non-magic. (In general, that's been one of the strengths of ObjC: very little magic.)


To be ever more pedantic, there is other magic involved when sending a message to a class. If there is no class method that matches the selector, the runtime will then search for instance methods of the root class. So you can use NSObject instance (like performSelector:) method on all NSObject subclasses.

http://www.sealiesoftware.com/blog/archive/2009/04/14/ objc_explain_Classes_and_metaclasses.html

-- Jean-Daniel

Yes, I've noticed this, it also works if you put an app-wide (via .pch file) Category on NSObect, so you can define your own Catch All + methods, which is very cool IMO!

All the Best
Dave



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References: 
 >Another Gnarly Objective-C Question! (From: Dave <email@hidden>)
 >Re: Another Gnarly Objective-C Question! (From: Graham Cox <email@hidden>)
 >Re: Another Gnarly Objective-C Question! (From: Wim Lewis <email@hidden>)
 >Re: Another Gnarly Objective-C Question! (From: Jean-Daniel Dupas <email@hidden>)

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