Swift中不再有`private init`吗? [英] No more `private init` in Swift?

问题描述

我看到了许多在Swift中使用private init来限制对象构造的引用(例如此)，但是当我尝试(在Xcode 7.2.1 Playground中)时似乎无法实现:

I saw a number of references to using private init in Swift to restrict object construction (e.g. this), yet it does not seem to be possible when I try (in Xcode 7.2.1 Playground):

class C {
    private init() {}
}

var c = C() // No errors.

我错过了什么吗，或者这实际上是一个错误吗?

Am I missing something or is this actually a bug?

推荐答案

您可能希望private将使用限制在类定义之内，但这不是它的作用.

You're probably expecting private to restrict the use to within the class definition, but that's not what it does.

private的定义是将实体的使用限制为自己定义的源文件".

The definition of private is to "restrict the use of an entity to its own defining source file".

从Swift书中，访问控制" 章.

From the Swift book, "Access Control" chapter.

在Swift 3中，fileprivate的用途与private相同，现在private的限制更为严格，因为它将实体的使用限制为封闭的声明"

As of Swift 3 fileprivate does what private used to and private is now more restrictive in that it "restricts the use of an entity to the enclosing declaration"

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