将结构实例上的方法作为参数传递

Question

I have a function that accepts a function as a parameter:

func send(n int, c func(x int) int) int {
    return c(n)
}

and I have a structure with a method defined on it

type data struct {
    value int
}

func (t *data) set(x int) {
    t.value = x
}

I would like to create an instance of the structure and pass method set bound to this instance to the send function as the second parameter, to set the value field from send.

Is this possible?

https://play.golang.org/p/bv1JevQBcq

Answer 1

You can use a method value. Here's something similar to your example:

package main

import "fmt"

func send(n int, c func(x int)) {
    c(n)
}

type data struct {
    value int
}

func (t *data) set(x int) {
    t.value = x
}

func main() {
    d := data{1}
    fmt.Println(d)
    send(2, d.set)
    fmt.Println(d)
}

playground example

I could not use the types in the question because the function argument to send returns a value and the method does not. If you do need to use the types in the question, then use an anonymous function to adapt the method to the function argument type:

 send(2, func(v int) int { d.set(v); return 0 })