I've been trying to wrap my head around the concept of interfaces in Go. Reading this and this helped a lot.
The only thing that makes me uncomfortable is the syntax. Have a look at the example below:
package main
import "fmt"
type Interface interface {
String() string
}
type Implementation int
func (v Implementation) String() string {
return fmt.Sprintf("Hello %d", v)
}
func main() {
var i Interface
impl := Implementation(42)
i = impl
fmt.Println(i.String())
}
My issue is with i = impl
. Based on the fact that an interface instance actually holds a pointer reference to the actual data, it would feel more natural for me to do i = &impl
. Usually assignment of non-pointer when not using &
will make a full memory copy of the data, but when assigning to interfaces this seem to side-step this and instead simply (behind the scenes) assign the pointer to the interface value. Am I right? That is, the data for the int(42)
will not be copied in memory?