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f# - 如何在给定条件下执行操作？

问题描述

我正在尝试将doIf函数从 C# 移植到 F#。

这是 C# 代码：

static void DoIf(bool c, Action f)
{
    if (c) {
        f();
    }
}

这是我的猜测：

let doIf (c: bool) (f: unit -> unit) :unit = 
    if c
    then f ()
    else ???

如果我写doIf true (fun _ -> printfn "hello")，它会打印hello。

但我不确定我应该怎么做else才能满足表达。

标签： f#

解决方案

While the answer provided by @aloisdg is as such correct, you don't actually need to explicitly return unit if c = false. Also, the type annotations aren't needed. I would go with

let doIf c f = if c then f()

Now the question I would ask myself is whether I actually need the function. In your example, for instance, the number of characters without the doIf function is actually less than with and I personally think it reads more easily as well

doIf true (fun _ -> printfn "hello")
if true then printfn "hello"

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