小编slo*_*oik的帖子

根据 Apple Swift 文档defer

无论执行如何离开当前代码块，无论它是因为抛出错误还是因为诸如 return 或 break 之类的语句而离开，此语句都允许您执行任何应该执行的必要清理。

文件

但是这段代码：

enum SomeError: ErrorType {
    case BadLuck
}

func unluckey() throws {
    print("\n\tunluckey() -> someone will have a bad day ;)\n")
    throw SomeError.BadLuck
}

func callsUnluckey() throws {

    print("callsUnluckey() -> OPENING something")
    defer {
        print("callsUnluckey() -> CLOSEING something")
    }

    print("callsUnluckey() -> WORKING with something")

    try unluckey()
    print("callsUnluckey() -> will never get here so chill...")

    defer {
        print("callsUnluckey() -> why this is not getting called?")
    }
}

do {
    try …