Re: Implementing delegate categories for subclasses

On Sep 10, 2009, at 9:05, Christiaan Hofman wrote:

>
> On Sep 10, 2009, at 4:45, Kyle Sluder wrote:
>
>> On Wed, Sep 9, 2009 at 7:35 PM, David Dunham <[email protected]> wrote:
>>> BTW, Apple still supports 10.4 with iTunes. (Which obviously isn't  
>>> Intel-64,
>>> but it's apparently still a market too big for them to ignore.)
>>
>> So?  That doesn't mean they need to compile the same code on 10.4 and
>> 10.6.  They can link against the 10.6 SDK with a deployment target of
>> 10.4, which is the recommended way of doing cross-target development.
>>
>> --Kyle Sluder
>
> Again, at this point this is not an option for me, for various  
> reasons.
>
> Christiaan
>

Anyway, I found a solution that allows me to use any SDK and not to  
complicate complicate too much. It is based on a set of macros that  
are set (e.g. in the .pch) conditionally on the SDK:


#if defined (MAC_OS_X_VERSION_10_5) && MAC_OS_X_VERSION_MAX_ALLOWED >  
MAC_OS_X_VERSION_10_5
#define OPTIONAL(name) @optional
#define CONFORM(name) <name>
#elif defined(MAC_OS_X_VERSION_10_4) && MAC_OS_X_VERSION_MAX_ALLOWED >  
MAC_OS_X_VERSION_10_4
#define OPTIONAL(name) @optional
#define CONFORM(name)
#else
#define OPTIONAL(name) @end @interface NSObject (name)
#define CONFORM(name)
#endif


I can then declare delegates as follows (if the superclass has a  
delegate I don't need the delegate ivar):


@protocol FooDelegate <NSObject>
// declare required delegate methods
OPTIONAL(FooDelegate)
// declare optional delegate methods
@end

@interface Foo : NSObject {
	// declare ivars
	id CONFORM(FooDelegate) delegate;
}
// declare methods
- (id CONFORM(FooDelegate))delegate;
- (void)setDelegate:(id CONFORM(FooDelegate))aDelegate;
@end


If I don't want to support the 10.4 SDK (or earlier) I can forget  
about the OPTIONAL macro and just directly use @optional.

Christiaan