枚举构造函数（创建成员的成员） [英] enum constructors (creating members of members)

问题描述

在D中，我试图创建一个枚举，其成员有成员。我可以更好地解释一下我想用一个例子，其中 s 和 i - 我想创建：

In D, I'm trying to create an enum whose members have members. I can better explain what I'm trying to do with an example, where s and i stand in for the sub-members I'm trying to create:

在Python中，我可以这样做：

In Python, I can do this:

class Foo(enum.Enum):
    A = "A string", 0
    B = "B string", 1
    C = "C string", 2

    def __init__(self, s, i):
        self.s = s
        self.i = i

print(Foo.A.s)

---

Java可以这样做：

---

Java can do something like this:

public enum Foo {
    A("A string", 0),
    B("B string", 1),
    C("C string", 2);

    private final String s;
    private final int i;

    Foo(String s, int i) {
        this.s = s;
        this.i =i;
    }
}

---

我如何在D中这样做？我在官方教程中没有看到任何东西。

---

How do I do this in D? I don't see anything in the official tutorial. If for whatever reason I can't do this in D, what's a good alternative?

推荐答案

你可以用任何方法构建一个枚举类型，这里我们使用一个元组（很像python）和一个别名，它更容易输入。

You can build an enum with any type, here we use a tuple (much like python) with a little alias for it to be easier to type.

import std.stdio;
import std.typecons;

alias FooT = Tuple!(string, "s", int, "i");
enum Foo : FooT {
    A = FooT("A string", 0),
    B = FooT("B string", 1),
    C = FooT("C string", 2),
}


void main(string[] args) {
    writeln(Foo.A.s);
}

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