F#,在不使用临时变量

时间:2017-11-07 06:44:10

标签: f#

我想在不使用临时变量或lambda的情况下将变量传递给匹配大小写。想法:

let temp =
    x 
    |> Function1
    |> Function2
    // ........ Many functions later.
    |> FunctionN

let result =
    match temp with
    | Case1 -> "Output 1"
    | Case2 -> "Output 2"
    | _ -> "Other Output"

我希望写下类似于以下内容的内容:

// IDEAL CODE (with syntax error)
let result =
    x
    |> Function1
    |> Function2
    // ........ Many functions later.
    |> FunctionN
    |> match with   // Syntax error here! Should use "match something with"
        | Case1 -> "Output 1"
        | Case2 -> "Output 2"
        | _ -> "Other Output"

我最接近的是使用lambda。但我认为下面的代码也不是那么好,因为我仍在“命名”临时变量。

let result =
    x
    |> Function1
    |> Function2
    // ........ Many functions later.
    |> FunctionN
    |> fun temp -> 
        match temp with   
        | Case1 -> "Output 1"
        | Case2 -> "Output 2"
        | _ -> "Other Output"

另一方面,我可以用大块代码直接替换“temp”变量:

let result =
    match x 
          |> Function1
          |> Function2
          // ........ Many functions later.
          |> FunctionN with
    | Case1 -> "Output 1"
    | Case2 -> "Output 2"
    | _ -> "Other Output"

是否可以编写类似于Code#2的代码?或者我必须选择Code#3还是#4?谢谢。

1 个答案:

答案 0 :(得分:16)

let result =
    x
    |> Function1
    |> Function2
    // ........ Many functions later.
    |> FunctionN
    |> function  
        | Case1 -> "Output 1"
        | Case2 -> "Output 2"
        | _ -> "Other Output"