约束构造器 (Yuēshù Gòuzàoqì)

便捷的自动布局方法以及通过函数构建器应用约束的能力

someView.extendToSuperview()
someOtherView.extendToSuperviewLayoutMargins()
centeredView.center(in: mySpecialLayoutGuide)

someView.applyConstraints {
	$0.leadingAnchor.constraint(equalTo: contentView.layoutMarginsGuide.leadingAnchor)
	$0.centerYAnchor.constraint(equalTo: contentView.layoutMarginsGuide.centerYAnchor)
}