在最后一个链接的option.bind中得到中间值了吗?

let getHtml location = 
    let request (url:string) = 
        let response = httpRequest (getFullUri url)
        response.Headers.TryFind "Location"

    request location  
    |> Option.bind (fun x -> request x) 
    |> Option.bind (fun x -> request x) // need the return of httpRequest inside request

我要代码返回的最后一个调用 httpRequest . 不是归还 request 。

更新:尝试了以下代码。最后一个错误 snd . 我想我可以使用可变变量来实现它。但这是习惯用法吗?

let getHtml location = 
    let request (url:string) = 
        let response = httpRequest (getFullUri url)
        match response.Headers.TryFind "Location" with 
        | Some location -> Some location, response
        | None -> None, response

    request location |> fst
    |> Option.bind (fun x -> request x |> fst) 
    |> Option.bind (fun x -> request x |> snd) // Error on snd

使用可变变量?

let getHtml location = 
    let mutable resp : FSharp.Data.HttpResponse = ???
    let request (url:string) = 
        let response = httpRequest (getFullUri url)
        resp <- response
        response.Headers.TryFind "Location"

    request location 
    |> Option.bind (fun x -> request x) 
    |> Option.bind (fun x -> request x)

    if not (resp = null) then Some resp else None