interfaces

Interfaces

No keyword like extends, if you implement all the methods then you can be that type

So everything is the empty interface{}

type Animal interface {
    Speak() string
}

Usage

type Dog struct {
    //...
}

func (d Dog) Speak() string {
    return "Woof"
}

func main() {
    poodle:= Animal(Dog()) //cast as Animal
}

The empty interface

• Specifies no methods

• May hold values of any type like fmt.Println

interface{}

An empty interface may hold values of any type. (Every type implements at least zero methods.)