Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

update chapter Protocols to swift 3.0 #655

Merged
merged 1 commit into from
Sep 21, 2016
Merged

update chapter Protocols to swift 3.0 #655

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 10 additions & 7 deletions source/chapter2/22_Protocols.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,10 +10,13 @@

> 2.1
> 翻译：[小铁匠Linus](https://github.com/kevin833752)
> 校对：[shanks](http://codebuild.me)，2015-11-01
> 校对：[shanks](http://codebuild.me)
>
> 2.2
> 翻译+校对：[SketchK](https://github.com/SketchK) 2016-05-16
> 翻译+校对：[SketchK](https://github.com/SketchK)
>
> 3.0
> 校对：[CMB](https://github.com/chenmingbiao)

本页包含内容：

Expand Down Expand Up @@ -614,7 +617,7 @@ protocol SomeClassOnlyProtocol: class, SomeInheritedProtocol {
<a name="protocol_composition"></a>
## 协议合成

有时候需要同时采纳多个协议，你可以将多个协议采用 `protocol<SomeProtocol, AnotherProtocol>` 这样的格式进行组合，称为 *协议合成（protocol composition）*。你可以在 `<>` 中罗列任意多个你想要采纳的协议，以逗号分隔。
有时候需要同时采纳多个协议，你可以将多个协议采用 `SomeProtocol & AnotherProtocol` 这样的格式进行组合，称为 *协议合成（protocol composition）*。你可以罗列任意多个你想要采纳的协议，以与符号(`&`)分隔。

下面的例子中，将 `Named` 和 `Aged` 两个协议按照上述语法组合成一个协议，作为函数参数的类型：

Expand All @@ -629,17 +632,17 @@ struct Person: Named, Aged {
var name: String
var age: Int
}
func wishHappyBirthday(celebrator: protocol<Named, Aged>) {
print("Happy birthday \(celebrator.name) - you're \(celebrator.age)!")
func wishHappyBirthday(to celebrator: Named & Aged) {
print("Happy birthday, \(celebrator.name), you're \(celebrator.age)!")
}
let birthdayPerson = Person(name: "Malcolm", age: 21)
wishHappyBirthday(birthdayPerson)
wishHappyBirthday(to: birthdayPerson)
// 打印 “Happy birthday Malcolm - you're 21!”
```

`Named` 协议包含 `String` 类型的 `name` 属性。`Aged` 协议包含 `Int` 类型的 `age` 属性。`Person` 结构体采纳了这两个协议。

`wishHappyBirthday(_:)` 函数的参数 `celebrator` 的类型为 `protocol<Named，Aged>`。这意味着它不关心参数的具体类型，只要参数符合这两个协议即可。
`wishHappyBirthday(_:)` 函数的参数 `celebrator` 的类型为 `Named & Aged`。这意味着它不关心参数的具体类型，只要参数符合这两个协议即可。

上面的例子创建了一个名为 `birthdayPerson` 的 `Person` 的实例，作为参数传递给了 `wishHappyBirthday(_:)` 函数。因为 `Person` 同时符合这两个协议，所以这个参数合法，函数将打印生日问候语。

Expand Down