Re: [Skim-app-develop] Super in init

[Adam R. M. <ama...@ma...>]

 
On Thursday, June 14, 2007, at 08:28AM, "Christiaan Hofman" <cmh...@gm...> wrote:
>I am very much confused by the behavior of super. I thought it always  
>referred to the instance 'self' referring to the implementation of  
>its superclass to look up methods. So what happens if I re-assign  
>self, does it still refer to the current self with the superclass's  
>implementation of the current self? Or does it somehow stick with the  
>superclass of the original self?

That's an interesting problem.  My read of the docs for objc_msgSendSuper is that the objc_super structure is generated at compile time when a super keyword is found.  Since you're changing the immediate superclass at runtime, I think super would still point to the original superclass.  

>Let me give the concrete problem. In -[PDFAnnotation  
>initWithDictionary:], I did something like:
>
>...
>self = [[SKPDFAnnotationNote alloc] initWithBounds:bounds];
>...
>[(PDFAnnotationText *)super setIconType:iconType];
>...
>
>This gave me a run time error, saying that SKPDFAnnotationNote does  
>not implement -setIconType. Even though it inherits it from its  
>superclass (and moreover I call super, sot self, so why would it even  
>look in SKPDFAnnotation's implementation?)

As to why the error says SKPDFAnnotationNote doesn't implement setIconType:, I don't know.  It might be interesting to override -doesNotRecognizeSelector: in both classes and see what the call sequence is (or maybe just look at when the exception is raised).

-- 
adam