Re: valueForKey and NSArray

• Subject: Re: valueForKey and NSArray
• From: "Michael Ash" <email@hidden>
• Date: Sun, 25 Jun 2006 13:40:46 -0400
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But I don't know how to state "do it as usual" in code:-(

@implementation NSArray (keyPath)
- (id) valueForKey:(NSString *)aKey;
{
    if([aKey isEqual:[NSString stringWithFormat:@"%d",[aKey intValue]]]) {
        if([self count] > [aKey intVaue])
            return [self objectAtIndex:[aKey intValue]];
        return   RETURNVALUE_AS_USUAL;
}
@end

"Do it as usual" is generally done by invoking super's implementation.
However, in a category on NSArray, super's implementation is NSObject,
which is not what you want. This is a problem with categories, in that
it's impossible to call the original implementation of a method you
replace.

To get around this, either investigate using poseAsClass: or method
swizzling (http://www.cocoadev.com/index.pl?MethodSwizzling). Both of
these techniques allow you to call the old implementation in your
override.

Mike
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