Question

我目前正在尝试将项目从Swift 2迁移到Swift 3，我看到一些objc属性块的问题。

我有这个objc类：

@class Result;
typedef id (^mapResultFunction)(id value);
typedef Result * (^flatMapResultFunction)(id value);

typedef void(^resultSuccess)(id value);
typedef void(^resultFailure)(NSError *error);

@class AsyncResult;
typedef AsyncResult * (^flatMapAsyncResultFunction)(id value);
typedef Result * (^catchFailureResultFunction)(NSError *error);

@interface AsyncResult : NSObject
@property (nonatomic, strong, readonly) AsyncResult * (^success)(resultSuccess success);
@property (nonatomic, strong, readonly) AsyncResult * (^failure)(resultFailure failure);

在Swift 2中，这种用法编译得很好：

asyncResult
.success { result in
    // show result
}?
.failure { error in
    // show error
}

但是现在使用Swift 3，我得到了这个编译错误： Cannot call value of non-function type '((resultSuccess?) -> AsyncResult?)!'

我看到生成的Swift代码是：

public typealias mapResultFunction = (Any?) -> Any?
public typealias flatMapResultFunction = (Any?) -> Result?

public typealias resultSuccess = (Any?) -> Swift.Void
public typealias resultFailure = (Error?) -> Swift.Void

public typealias flatMapAsyncResultFunction = (Any?) -> AsyncResult?
public typealias catchFailureResultFunction = (Error?) -> Result?

open class AsyncResult : NSObject {

    open var success: ((__ObjC.resultSuccess?) -> AsyncResult?)! { get }

    open var failure: ((__ObjC.resultFailure?) -> AsyncResult?)! { get }
}

这些__ObjC看起来很可疑，所以我尝试编写自己的代码：

class AsyncResult {

   var success: (((Any) -> (Void)) -> AsyncResult?)!

   var failure: (((Error) -> Void) -> AsyncResult?)!
}

这样称呼它最终会起作用：

let r = AsyncResult()

r.success { result in
    print("Hi")
}?.failure { failure in
    print("Error")
}

有没有人知道Swift 3中有什么变化？我能做些什么来解决这个问题？

Answer 1

我找到了罪魁祸首。问题实际上是在关闭内部。

asyncResult
.success { result in
    showResult(result)
}?
.failure { error in
    // show error
}

当showResult期待AnyObject时

。在Swift 3中，它现在是Any ...

你会认为Xcode会显示该行中的错误......

迁移到Swift 3期间出现objc属性块问题

1 个答案: