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Re: Subclass

On Saturday, June 14, 2003, at 03:52 AM, email@hidden wrote:

Sorry, that doesn't do what I need.

You don't really need this (a syntax and compile time check) in Objective C. There was a discussion about this very recently on cocoa-dev.

I have an object (call it F) of class foo and an object of class foo-bar (call it FB).

class foo-bar is a sub-class of foo.
class foo does implement some methods but would like to leave others to the sub-classes.

Another object (call it test) would like to call methods on objects of super-class type foo. However, foo is never instantiated, only subclasses are. Also, I'd like to have foo declare some methods that it doesn't implement but I would like to guarantee sub-classes implement. Protocols aren't that strict.

Please correct me if I'm wrong here.`

Is there another way to do this in Obj-C.

At runtime. You can implement these methods to send a doesNotRecognizeSelector: message. Or, there used to be a subclassResponsibility: method in NSObject, but it's not there anymore. You could create one that raises a meaningful exception and use it.

Marco Scheurer
Sen:te, Lausanne, Switzerland http://www.sente.ch
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 >Re: Subclass (From: email@hidden)



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