英文:
How to avoid interface method implementations that needs a pointer receiver?
问题
考虑以下示例：http://play.golang.org/p/eAot_sVwND
package main
import "fmt"
type Incrementor interface {
Increment()
}
type Counter struct {
i int
Incrementor
}
func (c *Counter) Increment(){
c.i++
}
func main() {
var c Incrementor
c = &Counter{}
c.Increment()
fmt.Println(c)
}
不幸的是，我需要使用c = &Counter{}，因为Counter.Increment()的实现具有指针接收器，否则c.Increment()调用将无法修改c.x属性：
func (c Counter) Increment(){
c.i++ // 没有错误，但现在我们在具有c副本的上下文中递增c.x
}
如何使原始实现在c = &Counter{}上不需要&？换句话说，如何完全避免在C.Increment实现中需要指针接收器？
这只是一个小问题，但我认为在Go中可能不需要使用指针来实现这个。
英文:
Consider the following example: http://play.golang.org/p/eAot_sVwND
package main
import "fmt"
type Incrementor interface {
Increment()
}
type Counter struct {
i int
Incrementor
}
func (c *Counter) Increment(){
c.i++
}
func main() {
var c Incrementor
c = &Counter{}
c.Increment()
fmt.Println(c)
}
Unfortunatelly I need to c = &Counter{} because Counter.Increment() implementation has a pointer receiver otherwise c.Increment() calls won't be able to modify c.x property:
func (c Counter) Increment(){
c.i++ // no errors, but now we increment c.x having a copy of c as context
}
How to make original implementation works without & on c = &Counter{}? In other words, how to avoid the need for the pointer receiver on C.Increment implementation at all?
This is just a nit, but I think that maybe a pointer is not necessary to do that in Go.
答案1
得分: 4
这只是一个小问题，但我认为在Go中可能不需要使用指针来实现这个。
考虑到Go通常通过值传递一切，使用指针接收器是实现你想要的自然方式。
这在Go FAQ中得到了支持：
首先，也是最重要的，方法是否需要修改接收器？如果需要修改，接收器必须是指针。
你可以在"Things I Wish Someone Had Told Me About Golang: pointers"中找到类似的结论。
英文:
> This is just a nit, but I think that maybe a pointer is not necessary to do that in Go.
Considering that Go uses to pass everything by value, a pointer receiver is the natural way to achieve what you want.
This is supported by the Go FAQ:
> First, and most important, does the method need to modify the receiver? If it does, the receiver must be a pointer.
You would find a similar conclusion in "Things I Wish Someone Had Told Me About Golang: pointers"
答案2
得分: 2
你可以考虑定义一个NewCounter函数，该函数封装了你的类型（或第三方类型）的初始化，并返回一个*Counter。使用方法可能如下所示：
func main() {
c := NewCounter()
c.Increment()
fmt.Println(c)
}
英文:
You could consider defining an NewCounter function that encapsulates the initialization of your type (or some 3rd party) and returns a *Counter. Usage could look something like this:
func main() {
c := NewCounter()
c.Increment()
fmt.Println(c)
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论