GolangInterfaceMagic.go

package example

import "fmt"

type Resource interface {
  Href() string
}

type Customer struct {
    Id      UUID.uuid 
    Name    string
}

func (c Customer) Href() {
  return fmt.Sprintf("https://%s/%s", "example.com", c.Id)
}

type Account struct {
    Id        UUID.uuid
    UserHref  Resource
}

func (a *Account) Build(c Customer) error{
  if c != nil {
    return errors.New("Cannot do this without a user")
  }
  a.UserHref = c
  return nil
}