在 F# 中以无点样式匹配？

Question

考虑这段代码：

type Fruit = Apple | Banana

let totalCost fruits = 
  fruits
  |> Seq.map (fun fruit -> 
    match fruit with
    | Apple -> 0.50
    | Banana -> 0.70
  )
  |> Seq.sum

我可以重写 totalCost 以使其更简洁，从而删除 fruit 标识符吗？

像这样：

// Not real code
let totalCost fruits = 
  fruits
  |> Seq.map (
    match
    | Apple -> 0.50
    | Banana -> 0.70
  )
  |> Seq.sum

Answer 1

您要找的关键词是function:

|> Seq.map ( 
    function
    | Apple -> 0.50 
    | Banana -> 0.70
)

function 脱糖为 fun x -> match x with

在 F# 中以无点样式匹配？

Matching in a point-free style in F#?

syntax

f#

pattern-matching

pointfree