Data hiding - the integer can only be modified/accessed through the get/set functions.

gistfile1.go

type obj_interface struct{
   set func(y int)
   get func() int
}

func instantiate() *obj_interface  {
  var x int
  var o = new(obj_interface)
  o.set = func(y int){
     x = y
  }
  o.get = func() int{
     return x
  }
  return o
}