.net 在 F# 中处理 Option Some(null) 的好策略是什么

我是F#语言的新手，当使用带有字符串值的选项类型匹配一些和无时，我遇到了异常.这是使用FSCheck发现的.在给定(字符串选项)属性类型的情况下，如果分配的字符串的值为空，则会引发空引用异常，从而导致值=Some(空).我的预期(错误的)是，这将导致零.幼稚的方法是判断一些和不判断，如果是一些，添加一个后续的匹配来处理一些(空).我使用的不那么天真的方法是(Match Option.ofObj optValue与…).这似乎是违反直觉的，因为我必须在处理具有可以赋值为空的值的选项类型的任何地方重复这种模式.

使用的类型

type LoanApplication =
{ Name: string
  Age: int
  CreditScore: int option
  Website: string option
  Email: string option
  PhoneNumber: string option }

在匹配输入时抛出空引用的函数

    member this.processApplication(application: LoanApplication) =
    //we want to create a person
    //do we have a valid application
    let getValidRequest (input: string option) =
        match input with
        | None -> IsUrl false
        | Some optValue ->
                let isUrl = optValue.StartsWith("http://")
                let isEmail = optValue.ToString().Contains("@")
                let isPhone = optValue.ToString().StartsWith("+")

                match isUrl, isEmail, isPhone with
                | true, _, _ -> IsUrl true
                | _, true, _ -> IsEmail true
                | _, _, true -> IsPhone true
                | _ -> IsUrl false


    let validateTypeFields (application: LoanApplication) =
        match (getValidRequest application.Email), (getValidRequest application.PhoneNumber) with
        | IsEmail true, IsPhone true ->
            Valid
                { Name = application.Name
                  Age = application.Age
                  CreditScore = application.CreditScore
                  Website = application.Website
                  Email = application.Email.Value
                  PhoneNumber = application.PhoneNumber.Value }
        | _ -> Invalid application


    let validationResult = validateTypeFields application

    match validationResult with
    | Valid validApplication -> ProspectiveApplication validApplication
    | Invalid application -> InvalidApplication application

测试设置调用失败的函数(注意:FSCheck是将一些(空)分配给设置中的函数，以澄清问题.

    [<Fact>]
member this.IsTheTestThatIsFailing() =
    let application: LoanApplication =
        { Name = "Joe"
          Age = 30
          CreditScore = Some(700)
          Website = Some("http://www.google.com")
          Email = Some(null)
          PhoneNumber = Some("+123456789") }

    let processor = new ApplicantProcess()
    let result = processor.processApplication application

    match result with
    | ValidApplication validApplication
    | ProspectiveApplication validApplication -> Assert.True(false)
    | InvalidApplication application -> Assert.True(true)

处理选项(空)或从一开始就防止它们的一些正确方法是什么？ 在我的示例中，我想要一个字符串值不能赋值为空的属性.