函数可以作为参数传递吗? [英] Can functions be passed as parameters?

问题描述

在Java中，我可以做类似

In Java I can do something like

derp(new Runnable { public void run () { /* run this sometime later */ } })

并在以后的方法中运行"代码.处理(匿名内部类)很痛苦，但是可以做到.

and "run" the code in the method later. It's a pain to handle (anonymous inner class), but it can be done.

Go有什么可以促进函数/回调作为参数传递的东西吗?

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

推荐答案

是的，请考虑以下示例:

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

游览: https://tour.golang.org/moretypes/25 (函数闭包)

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