ios - 抛出异常的 Swift2 闭包

Question

我正在尝试创建一个可以抛出异常的闭包，并将其作为参数传递给另一个函数。例如:

extension NSManagedObjectContext {

  /// The same as performBlockAndWait, except it can handle closures that throw.
  func performBlockAndWaitOrThrow(block: (() -> throws Void)) throws {
    // ...
    try block()
  }
}

请注意| block | argument 是一个可以抛出异常的闭包。

但是，这无法编译。有什么办法可以做到这一点吗？

Answer 1

throws 关键字应位于箭头之前。编译如下:

extension NSManagedObjectContext {

    /// The same as performBlockAndWait, except it can handle closures that throw.
    func performBlockAndWaitOrThrow(block: (() throws -> Void)) throws {
        // ...
        try block()
    }
}