有方法文字吗？

Question

Is it possible to define a method literal? Something like the code below but working.

type Fn struct{
    sw Dialer
}
var x fn
fn := func (x Fn) Reboot() error {  }

Answer 1

No, but you can use a "function value", so that it can be assigned later on. A common one in network related packages is for a struct to have a Dial func(network, addr string) (net.Conn, error) field that can be replaced with a custom dialer (e.g. http.Transport)

type Fn struct {
    Reboot func() error
}

func main() {
    f := Fn{}
    f.Reboot = func() error {
        return nil
    }
    f.Reboot()
}