Re: How to initialise an array class inheriting from NSArray?

[David Ayers]

>   - (id) init
>  {
>    self = [super initWithObjects: ...];
>    return self;
>  }

I also would advise you to learn about categories...

http://developer.apple.com/techpubs/macosx/Cocoa/ObjectiveC/3objc_language_overview/index.html
http://developer.apple.com/techpubs/macosx/Cocoa/ObjectiveC/3objc_language_overview/chapter_3_section_8.html

... before learning how to sublcass the abstract classes from class 
clusters such as NSArray.

All previously cited code examples (as above) would not return an 
instance of your class, but of a private subclass of the class cluster, 
which doesn't implement your additional methods.  Yet if you think a 
subclass is "The Right Thing" then please read:

http://developer.apple.com/techpubs/macosx/Cocoa/TasksAndConcepts/ProgrammingTopics/Foundation/Concepts/ClassClusters.html

Cheers,
David