interfaces_code_snippet_20.go

type movie string

func (m movie) Movie() string { return string(m) }

type movieStar string

func (m movieStar) Star() string { return string(m) }

func movieOrStar(m interface{}) string {
	switch v := m.(type) {
	case interface{ Star() string }:
		return v.Star()
	case interface{ Movie() string }:
		return v.Movie()
	default:
		return ""
	}
}

func main() {
	var value interface{}
	value = movieStar("Sylvester Stallone")
	fmt.Println(movieOrStar(value)) // Prints "Sylvester Stallone
	value = movie("Rambo")
	fmt.Println(movieOrStar(value)) // Prints "Rambo"
}