iOS高聚合写法

今天偶然在视频看到这样的的一段写法，看起来比较有趣，故保存下来。借此在网上一查，说是一种高聚合的写法，这样可以增加代码的拓展性、可读性

UICollectionViewFlowLayout *layout = ({ 
       UICollectionViewFlowLayout *layout =  [[UICollectionViewFlowLayout alloc] init];
        layout.itemSize = CGSizeMake(cellWH, cellWH);
        layout.minimumInteritemSpacing = margin;
        layout.minimumLineSpacing = margin;
        layout;
    });

    UICollectionView *collectionView = ({
        UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, BSScreenW, 0) collectionViewLayout:layout];
        collectionView.dataSource = self;
        collectionView.delegate = self;
        [collectionView registerNib:[UINib nibWithNibName:NSStringFromClass([BSSquareCell class]) bundle:nil] forCellWithReuseIdentifier:ID];
        collectionView.scrollEnabled = NO;
        collectionView;  
    });