Can I generically specifiy a Method for a Go-Lang Struct? - go

Question

I have been reading over the go-lang interface doc ; however it is still not clear to me if it is possible to achieve what I'd like
type A struct {
ID SomeSpecialType
}
type B struct {
ID SomeSpecialType
}
func (a A) IDHexString() string {
return a.ID.Hex()
}
func (b B) IDHexString() string {
return b.ID.Hex()
}
This will work fine; however I'd prefer some idiomatic way to apply the common method to both types and only define it once. Something Like:
type A struct {
ID SomeSpecialType
}
type B struct {
ID SomeSpecialType
}
func (SPECIFY_TYPE_A_AND_B_HERE) IDHexString() string {
return A_or_B.ID.Hex()
}

Answer 1

Essentialy you can't like you're used to, but what you can do is anonymously inherit a super-struct (sorry it's not the legal word :P):
type A struct {
}
type B struct {
A // Anonymous
}
func (A a) IDHexString() string {
}
B will now be able to implement the IDHexString method.
This is like in many other languages kind of the same as:
class B extends A { ... }

Answer 2

For example, using composition,
package main
import "fmt"
type ID struct{}
func (id ID) Hex() string { return "ID.Hex" }
func (id ID) IDHexString() string {
return id.Hex()
}
type A struct {
ID
}
type B struct {
ID
}
func main() {
var (
a A
b B
)
fmt.Println(a.IDHexString())
fmt.Println(b.IDHexString())
}
Output:
ID.Hex
ID.Hex