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| -rw-r--r-- | objective-c.html.markdown | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/objective-c.html.markdown b/objective-c.html.markdown index f130ea0c..05bb5c6a 100644 --- a/objective-c.html.markdown +++ b/objective-c.html.markdown @@ -599,6 +599,52 @@ int main (int argc, const char * argv[]) { @end +// Starting in Xcode 7.0, you can create Generic classes, +// allowing you to provide greater type safety and clarity +// without writing excessive boilerplate. +@interface Result<__covariant A> : NSObject + +- (void)handleSuccess:(void(^)(A))success + failure:(void(^)(NSError *))failure; + +@property (nonatomic) A object; + +@end + +// we can now declare instances of this class like +Result<NSNumber *> *result; +Result<NSArray *> *result; + +// Each of these cases would be equivalent to rewriting Result's interface +// and substituting the appropriate type for A +@interface Result : NSObject +- (void)handleSuccess:(void(^)(NSArray *))success + failure:(void(^)(NSError *))failure; +@property (nonatomic) NSArray * object; +@end + +@interface Result : NSObject +- (void)handleSuccess:(void(^)(NSNumber *))success + failure:(void(^)(NSError *))failure; +@property (nonatomic) NSNumber * object; +@end + +// It should be obvious, however, that writing one +// Class to solve a problem is always preferable to writing two + +// Note that Clang will not accept generic types in @implementations, +// so your @implemnation of Result would have to look like this: + +@implementation Result + +- (void)handleSuccess:(void (^)(id))success + failure:(void (^)(NSError *))failure { + // Do something +} + +@end + + /////////////////////////////////////// // Protocols /////////////////////////////////////// |