在Swift中枚举具有相同值的多个个案 [英] Enum multiple cases with the same value in Swift

问题描述

在C语言中，您可以让您的枚举具有以下含义：

In C you could make your enums have this:

typedef enum _Bar {
    A = 0,
    B = 0,
    C = 1
} Bar;

在Swift中，我想做等价的。但是，编译器抱怨它不是唯一的。如何告诉我我希望两个个案的值相同？

In Swift I want to make the equivalent. However, the compiler complains that it isn't unique. How do I tell it that I want two cases to have the same value?

enum Bar : Int {
    case A = 0
    case B = 0 // Does not work
    case C = 1
}

我已经尝试过

case A | B = 0

和

case A, B = 0

但是它似乎并没有按照我的意愿工作。

But it doesn't seem to work as I want it to.

推荐答案

Swift不支持重复值（或语义上的别名）。如果您不介意，则可以使用类似以下的方式模仿它：

Swift doesn't support duplicated values (or "aliases" semantically). If you don't mind, you can mimic it by using something like this:

enum Foo: Int {
    case Bar = 0

    static var Baz:Foo {
        get {
            return    Bar
        }
    }
    static var Jar:Foo {
        get {
            return    Foo(rawValue: 0)!
        }
    }
}

使用Swift的最新版本，可以将其缩短像这样：

With recent version of Swift, this can be shortened like this:

enum Foo: Int {
    case bar = 0

    static var baz:Foo { .bar }
    static var jar:Foo { Foo(rawValue: 0)! }
}

请注意，Swift已将其枚举变量的命名约定从 PascalCase 到 camelCase 。

Note that Swift has changed their naming convention of enum variants from PascalCase to camelCase.

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