如何在 F# 中枚举受歧视的联合? [英] How to enumerate a discriminated union in F#?

问题描述

如何枚举 F# 中可区分联合的可能值"?

How can I enumerate through the possible "values" of a discriminated union in F#?

我想知道是否有类似 Enum.GetValues(Type) 之类的用于区分联合的东西，我不确定我会枚举什么样的数据.我想为每个选项生成一个可区分联合的列表或数组.

I want to know if is there something like Enum.GetValues(Type) for discriminated unions, tough I am not sure over what kind of data I would enumerate. I would like to generate a list or array of a discriminated union with one item for each option.

推荐答案

是的，F# 有它自己的反射层构建在 .NET 的反射之上，以帮助您理解特定于 F# 的类型，例如区分联合.这是让您枚举联合案例的代码:

Yes, F# has it's own reflection layer build on top of .NET's reflection to help you make sense of types that are specific to F#, like discriminating unions. Here's the code that will let you enumerate a union's cases:

open Microsoft.FSharp.Reflection

type MyDU =
    | One
    | Two
    | Three

let cases = FSharpType.GetUnionCases typeof<MyDU>

for case in cases do printfn "%s" case.Name

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