Type embedding

But what if you would like a struct to inherit the methods of another struct? The closest feature that the Go language offers to the concept of inheritance is known as type embedding. This feature is best explained through an example. Let's go back to the Person struct type:

type Person struct{
    name string
    age int
}

func (p Person) GetName()string{
  return p.name
}

func (p Person) GetAge()int{
  return p.age
}

Now, let's say that we would like to create a new struct type called Student, which has all the properties and methods of Person, plus some more:

type Student struct{
    Person
    studentId int
}

func (s Student) GetStudentID()int{
    return s.studentId
}

Notice that in the preceding code, we included the type Person inside the struct definition of type Student, without specifying a field name. This will effectively make the Student type inherit all the exported methods and fields of the Person struct type. In other words, we can access the methods and fields of Person directly from an object of type Student:

s := Student{}
//This code is valid, because the method GetAge() belongs to the embedded type 'Person':
s.GetAge()
s.GetName()

In Go, when a type gets embedded inside another type, the exported methods and fields of the embedded type are said to be promoted to the parent or embedding type.

Let's explore how to build interfaces in Go in the next section.