Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

package main

import "fmt"

// Base type
type Animal struct {
    Name string
}

func (a Animal) Speak() string {
    return a.Name + " makes a sound."
}

func (a Animal) Describe() string {
    return fmt.Sprintf("I am %s", a.Name)
}

// Dog embeds Animal
type Dog struct {
    Animal          // anonymous (embedded) field
    Breed  string
}

// Dog overrides Speak
func (d Dog) Speak() string {
    return d.Name + " says: Woof!"
}

// Logger shows embedding for cross-cutting concerns
type Logger struct {
    Prefix string
}

func (l Logger) Log(msg string) {
    fmt.Printf("[%s] %s
", l.Prefix, msg)
}

type Service struct {
    Logger              // embedded logger
    Name   string
}

func (s *Service) Start() {
    s.Log("starting service: " + s.Name) // promoted method
}

func main() {
    d := Dog{
        Animal: Animal{Name: "Rex"},
        Breed:  "Labrador",
    }

fmt.Println(d.Speak())       // Dog's own method
    fmt.Println(d.Describe())    // promoted from Animal
    fmt.Println(d.Name)          // promoted field

svc := Service{
        Logger: Logger{Prefix: "INFO"},
        Name:   "AuthService",
    }
    svc.Start()
}