创建或者添加Cocoa Auto Layout约束的可替代系统

源码AutoLayoutShorthand，Auto Layout Shorthand (ALS)是创建或者添加Cocoa Auto Layout约束的可替代系统，感觉有点像CSS，功能比较强大，且没有HTML令人沮丧的默认布局模式。 ALS介绍示例: [iconView als_addConstraints:@{ @"left ==": als_superview, @"width ==": @(kIconWidth), @"top ==": als_superview, @"height ==": @(kIconHeight), }]; alternative system for creating and adding Cocoa Auto Layout constraints