Swift 执行异步代码框架 BrightFutures

Swift 执行异步代码框架 BrightFutures。

我们经常会遇到写异步代码的情况，比如在等待网络响应后更新UI，或者在要执行耗时很长的运算后更新UI，通常我们会写类似下面的代码：

User.logIn(username, password) { user, error in
    if !error {
        Posts.fetchPosts(user, success: { posts in
            // do something with the user's posts
        }, failure: handleError)
    } else {
        handleError(error) // handeError is a custom function to handle errors
    }
}

使用BrightFutures后，代码将是这样的：

User.logIn(username,password).flatMap { user in
    Posts.fetchPosts(user)
}.onSuccess { posts in
    // do something with the user's posts
}.onFailure { error in
    // either logging in or fetching posts failed
}