MAX(), MIN()マクロのSwift版

Swiftではmax()およびmin()という関数があるようです。

/// Return the greatest argument passed

func max<T : Comparable>(x: T, y: T, z: T, rest: T...) -> T

/// Return the greater of `x` and `y`

func max<T : Comparable>(x: T, y: T) -> T

/// Return the lesser of `x` and `y`

func min<T : Comparable>(x: T, y: T) -> T

/// Return the least argument passed

func min<T : Comparable>(x: T, y: T, z: T, rest: T...) -> T

参考: generics - Swift equivalent for MIN and MAX macros - Stack Overflow