[英]F# forward type declarations
I stumbled across this problem in F#. 我偶然发现了F#中的这个问题。 Suppose, I want to declare two types that reference each other:
假设,我想声明两种相互引用的类型:
type firstType =
| T1 of secondType
//................
type secondType =
| T1 of firstType
//................
How do I do that, so the compiler does not generate an error? 我该怎么做,所以编译器不会生成错误?
You use 'and': 你使用'和':
type firstType =
| T1 of secondType
and secondType =
| T1 of firstType
I figured it. 我想通了。 It's:
它的:
type firstType =
| T1 of secondType
//................
and secondType =
| T1 of firstType
//................
限制是必须在同一文件中声明类型。
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