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Re: Comparing the Class



> …because you can't force an existing class to conform to a protocol
without subclassing.
A category can add a protocol adoption, actually.

-Ken

On Wed, Oct 15, 2008 at 6:37 PM, Graham Cox <email@hidden> wrote:

>
> On 16 Oct 2008, at 12:20 am, Ruotger Skupin wrote:
>
>  Hi,
>>
>> when comparing the class of two objects I usually do [obj1
>> isKindOfClass:[obj2 class]]. But if I say have the Class as an input value
>> to a method:
>>
>> - (void) bla:(Class) inClass
>> {
>>        if (/* inClass is an NSString */)
>>        {
>>                // do stuff
>>        }
>>        else if (/* inClass is an NSNumber */)
>>        {
>>                // do other stuff
>>        }
>> }
>>
>> Is it save to compare like this:
>>
>>        inClass == [NSString class]
>>
>> or do I have to e.g.:
>>
>>        [[NSNumber numberWithInt:0] isKindOfClass:inClass]
>>
>> Roddi
>>
>
>
> As well as what others have said, consider not testing the class at all but
> instead testing for a response to a particular message of interest
> (so-called "duck typing" - see http://en.wikipedia.org/wiki/Duck_typing).
> That can be a lot more flexible. Another option is to declare a formal
> protocol that is common to the possible classes of interest, though in the
> example that wouldn't work because you can't force an existing class to
> conform to a protocol without subclassing.
>
> --Graham
>
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References: 
 >Comparing the Class (From: Ruotger Skupin <email@hidden>)
 >Re: Comparing the Class (From: Graham Cox <email@hidden>)



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