自定义打印协议CustomStringConvertible和CustomDebugStringConvertible

class Person {
    var age: Int = 10
}

extension Person: CustomStringConvertible {
    var description: String {
        "person age: \\(age)"
    }
}

extension Person: CustomDebugStringConvertible {
    var debugDescription: String {
        "debugPerson age: \\(age)"
    }
}

调用

let p = Person()
print(p)
debugPrint(p)

打印结果

person age: 10
debugPerson age: 10

当处于Release模式的时候，debugPrint也仍然会输出。目前看不出区别

当在控制台po的时候，调用的是CustomDebugStringConvertible的debugDescription方法