函数可以在Go中作为参数传递吗？ [英] Can Functions be passed as parameters in Go?

问题描述

在Java中，我可以做一些类似于 derp（new Runnable {public void run（）{/ *稍后运行它* /}}）和run代码在稍后的方法中。处理（匿名内部类）是一件痛苦的事情，但它可以完成。

In Java I can do something like derp(new Runnable { public void run () { /* run this sometime later */ } }) and "run" the code in the method later. It's a pain to handle (anonymous inner class), but it can be done.

Go有一些可以促进函数/回调作为参数传入的东西吗？

Does Go have something that can facilitate a function/callback being passed in as a parameter?

推荐答案

是的，考虑一下这些例子：

Yes, consider some of these examples:

package main

import "fmt"

// convert types take an int and return a string value.
type convert func(int) string

// value implements convert, returning x as string.
func value(x int) string {
    return fmt.Sprintf("%v", x)
}

// quote123 passes 123 to convert func and returns quoted string.
func quote123(fn convert) string {
    return fmt.Sprintf("%q", fn(123))
}

func main() {
    var result string

    result = value(123)
    fmt.Println(result)
    // Output: 123

    result = quote123(value)
    fmt.Println(result)
    // Output: "123"

    result = quote123(func(x int) string { return fmt.Sprintf("%b", x) })
    fmt.Println(result)
    // Output: "1111011"

    foo := func(x int) string { return "foo" }
    result = quote123(foo)
    fmt.Println(result)
    // Output: "foo"

    _ = convert(foo) // confirm foo satisfies convert at runtime

    // fails due to argument type
    // _ = convert(func(x float64) string { return "" })
}

播放： http：/ /play.golang.org/p/XNMtrDUDS0

旅程： https://tour.golang.org/moretypes/25 （功能闭包）

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