Alternative for String(describing:) or String(reflecting:)

String+Unwrap.swift

// MARK: - Optional Unwrap 并转化为字符串

extension String {
    
    enum UnwrapType {
        case describing
        case reflecting
    }
    
    /// 将任意的Optional类型转化为String，并不会用Optional(abc)这样的包裹形式
    ///
    /// - Parameter unwrap: 需要被unwrap的类型
    /// - Parameter type: unwrap的两种方式，其中reflecting方式会更详细
    /// - Returns: 转为String后的结果
    init<Subject>(unwrap instance: Subject?, type: UnwrapType = .describing) {
        guard let i = instance else {
            self.init("nil")
            return
        }
        switch type {
        case .describing:
            self.init(describing: i)
        case .reflecting:
            self.init(reflecting: i)
        }
    }
    
    var length: Int {
        get { return self.characters.count }
    }
}

// example
//struct Point {
//    let x: Int, y: Int
//}

//let s: Point? = Point(x: 3, y: 4)
//print(String(unwrap: s))
//print(String(unwrap: s, type: .reflecting))
//print(String(describing: s))
//print(String(reflecting: s))

// 输出（test是module名字）：
// Point(x: 3, y: 4)
// test.Point(x: 3, y: 4)
// Optional(test.Point(x: 3, y: 4))
// Optional(test.Point(x: 3, y: 4))

// Is this what you want? 这个结果是你想要的吗？
let a: String? = ""
print(String(describing: a)); 
// Optional("") 
// 也许你并不想要这个 Optional()