Examples of inheritance (embedded types) and interfaces in Go language

inheritance.go

package main

import (
    "fmt"
)

type (
    person struct {
        name string
        age  int
    }
    employee struct {
        person
        position string
    }
)

func main() {
    // Alternative initialization techniques
    // 
    // b := employee{
    //     person: person{
    //         name: "John",
    //         age:  25,
    //     },
    //     pos:  "Manager",
    // }
    // 
    // b := employee{person{"John", 25}, "Manager"}
    
    b := employee{}
    b.name = "John"
    b.age = 25
    b.position = "Manager"

    fmt.Println(b)
    // Outputs: {{John 25} Manager}
}

interface.go

package main

import (
	"fmt"
)

type (
	greeter interface {
		hello() string
	}
	cat struct{}
	dog struct{}
	cow struct{}
)

func (c cat) hello() string {
	return "meow!"
}

func (d dog) hello() string {
	return "bark!"
}

func (c cow) hello() string {
	return "mooo!"
}

func greet(g greeter) {
	hi := g.hello()
	fmt.Println(hi)
}

func main() {
	greet(cat{})
	// Outputs: meow!

	greet(dog{})
	// Outputs: bark!

	greet(cow{})
	// Outputs: mooo!
}