如何在父方法中调用子方法？ [重复]

Question

This question already has an answer here:

• Go embedded struct call child method instead parent method 1 answer

package main

import "fmt"

type Super struct{}

func (super *Super) name() string {
    return "Super"
}

func (super *Super) WhoAmI() {
    fmt.Printf("I'm %s.
", super.name())
}

type Sub struct {
    Super
}

func (sub *Sub) name() string {
    return "Sub"
}

func main() {
    sub := &Sub{Super{}}
    sub.WhoAmI()
}

I want to get "I'm Sub", but I get "I'm Super" instead.

I already know sub.WhoAmI will call sub.Super.WhoAmI, but I still want to know if there is a way to get "I'm Sub". In Python when I write following code:

class Super(object):

    def name(self):
        return "Super"

    def WhoAmI(self):
        print("I'm {name}".format(name=self.name()))

class Sub(Super):

    def name(self):
        return "Sub"


if __name__ == "__main__":
    sub  = Sub()
    sub.WhoAmI()

I can get "I'm Sub".

</div>

Answer 1

Embedding is not subclassing. There are no superclasses or subclasses in Go. Sub here is not a "child" of Super. It contains a Super. You can't do you're trying to do. You need to organize your code in a different way so that it's not needed.

For example, here (playground) is a more natural way to do this in Go:

package main

import "fmt"

type Namer interface {
    Name() string
}

type Super struct{}

func (sub *Super) Name() string {
    return "Super"
}

type Sub struct{}

func (sub *Sub) Name() string {
    return "Sub"
}

func WhoAmI(namer Namer) {
    fmt.Printf("I'm %s.
", namer.Name())
}

func main() {
    sub := &Sub{}
    WhoAmI(sub)
}

Rather than focus on classes (which Go doesn't have), this focuses on interfaces. It's not a question of what things are, it's a question of what they can do. This is a very powerful approach to programming, and in practice is often much more flexible and less error-prone than inheritance abstractions.