如何在F#中使用两个相互递归的结构类型？

Question

以下代码无法编译:

[<Struct>]
type Point(x:int, y:int) =
    member __.X = x
    member __.Y = y
    member __.Edges = ArrayList<Edge>()
[<Struct>]
and Edge(target:Point, cost:int) =
    member __.Target = target
    member __.Cost = cost

问题在于[<Struct>]属性,它们似乎与"和"构造冲突.

我应该怎么做呢？我知道我可以选择完成任务

type Point(x:int, y:int) =
    struct
        member __.X = x
        member __.Y = y
        member __.Edges = new ArrayList<Edge>()
    end
and Edge(target:Point, cost:int) =
    struct
        member __.Target = target
        member __.Cost = cost
    end

但我喜欢[<Struct>]简洁.

谢谢

Answer 1

在and令牌之后移动属性定义

and [<Struct>] Edge(target:Point, cost:int) =

Answer 2

详细说明Jared的答案:

每个F#规范(8.类型定义) 自定义属性可以紧接在类型定义组之前,在这种情况下,它们适用于第一个类型定义,或紧接在类型定义的名称之前

意思是你也可以使用这种风格:

type
    [<Struct>]
    A(x : int) = 
        member this.X = x
and
    [<Struct>]
    B(y : int) = 
        member this.Y = y