Now we have blocks in Objective-C, we no longer need to define standalone methods to implement a custom array sort. However, I’m always forgetting the exact syntax, so, mostly as a reminder to myself:
[alerts sortUsingComparator:(NSComparator)^(Alert *a1, Alert *a2) { if ([a1.severity compare:a2.severity] == NSOrderedSame) { return [a1.timeRaised compare:a2.timeRaised]; } else { return [a1.severity compare:a2.severity]; } }];