带有 `(反引号)的 Swift 变量名 [英] Swift variable name with ` (backtick)
问题描述
我在浏览 Alamofire 源代码时发现在 这个源文件
I was browsing Alamofire sources and found a variable name that is backtick escaped in this source file
open static let `default`: SessionManager = {
let configuration = URLSessionConfiguration.default
configuration.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
return SessionManager(configuration: configuration)
}()
但是在使用变量的地方没有反引号.反引号的目的是什么?
However in places where variable is used there are no backticks. What's the purpose of backticks?
删除反引号导致错误:
关键字default"不能在这里用作标识符
Keyword 'default' cannot be used as an identifier here
推荐答案
根据 Swift 文档:
要使用保留字作为标识符,请在其前后加上反引号 (`
).例如,class
不是有效的标识符,但 `class`
是有效的.反引号不被视为标识符的一部分;`x`
和 x
意义相同.
To use a reserved word as an identifier, put a backtick (
`
)before and after it. For example,class
is not a valid identifier, but`class`
is valid. The backticks are not considered part of the identifier;`x`
andx
have the same meaning.
在您的示例中,default
是 Swift 保留关键字,这就是需要反引号的原因.
In your example, default
is a Swift reserved keyword, that's why backticks are needed.
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