Method override in Go

override.go

package main

import (
	"fmt"
	"strings"
)

type Cap struct {
	message string
}

func (c *Cap) Do() string {
	return strings.ToUpper(c.message)
}

func (c *Cap) GetMessage() string {
	return c.message
}

// Embed Cap
type Greet struct {
	greeting string
	Cap
}

// Use embedded implementation
func (g *Greet) Do() string {
	superVal := g.Cap.Do()
	return fmt.Sprintf("%s %s!", g.greeting, superVal)
}

// Embed Cap
type Repeat struct {
	count int
	Cap
}

// Completely override embedded imlementation
func (r *Repeat) Do() string {
	return strings.Repeat(r.Cap.GetMessage(), r.count)
}

func main() {
	capper := Cap{"Bob"}
	fmt.Printf("capper.Do(): %+v\n", capper.Do())

	greeter := Greet{"Hello", capper}
	fmt.Printf("greeter.Do(): %+v\n", greeter.Do())

	greeter2 := Greet{"Bye", Cap{"Kate"}}
	fmt.Printf("greeter2.Do(): %+v\n", greeter2.Do())

	repeater := Repeat{3, Cap{"Anne "}}
	fmt.Printf("repeater.Do(): %+v\n", repeater.Do())
}