声明一个强类型的F#列表

Question

我在F#中有一个界面

type IStongList =
    abstract member ToStringList: float * float list

而且我在制作一个float,float元组列表时遇到了麻烦.

type MyTypw = struct 
    val L1: float
    val L2: float
    val M1: float
    val M2: float
    // . . .
    interface  IStrongList with
        member this.ToStrongList = 
            let one: float * float  = (this.L1,this.M1) 
            let two: float * float  = (this.L2,this.M2) 
            [
                one
                two
            ]
end

我得到的错误是:

This expression was expected to have type
    float * float list    
but here has type
    'a list 

我究竟做错了什么？

Answer 1

A float * float list是由a float和a 组成的元组float list,而不是由两个floats 组成的元组列表.为此你应该使用(float * float) list:

type IStrongList =
    abstract member ToStrongList: (float * float) list

如果您更改这样的界面,其余代码将正常工作.

您的代码中也存在一些拼写错误(IStongList→ IStrongList和ToStringList→ ToStrongList)但我会将这些错误归结为转录错误.