Locating child View Controllers based on restoration identifier

gistfile1.m

- (void)viewDidLoad {
  [super viewDidLoad];
  
  for (NSViewController *aController in self.childViewControllers) {
    NSString *identifier = [aController identifier];
    if ([identifier isEqualToString:@"master"]) {
      self.masterViewController = aController;
    }
    else if ([identifier isEqualToString:@"detail"]) {
      self.detailViewController = aController;
    }
  }
}