Go lang中的多态性

Question

I am learning go lang and i was wondering if there is a way to do something like this:

type Foo struct {
   ...
}

type Bar struct {
   Foo
   ...
}

func getFoo() Foo {
   return Bar{...}
}

In an object oriented language, such code should work without problems, but in go it throws me an error, saying that getFoo() must return an instance of class Foo.

Is there a way to do polymorphism similar to what i've described in Go?

Answer 1

Go is not a typical OO language. Also each language has it own way of doing things. You can use interface and composition to achieve what you desire to, as shown below:

package main

import "fmt"

type Foo interface {
   printFoo()
}

type FooImpl struct {

}

type Bar struct {
   FooImpl
}

type Bar2 struct {
   FooImpl
}

func (f FooImpl)printFoo(){
    fmt.Println("Print Foo Impl")
}

func getFoo() Foo {
   return Bar{}
}

func main() {
    fmt.Println("Hello, playground")
    b := getFoo()
    b.printFoo()
}

http://play.golang.org/p/iR8QkD3DnP