Classer is an interface to enhance go's embed struct with virtual member function in C++|Java It's used like this:import "github.com/searKing/golang/go/util/class"type Pet struct { class.Class} func (pet *Pet) Name() string { return "pet"} func (pet *Pet) VirtualUpperName() string { p := pet.GetDerivedElse(pet).(Peter) return strings.ToUpper(p.Name())} func (pet *Pet) UpperName() string { return strings.ToUpper(pet.Name())} Dog derived from Pettype Dog struct { Pet} func NewDogEmbedded() *Dog { return &Dog{}} func NewDogDerived() *Dog { dog := &Dog{} dog.SetDerived(dog) return dog} func (dog *Dog) Name() string { return "dog"}.