scala> def fo() = {
     |   var i=0
     |   var s="init"
     |    () => {
     |      if (s == "init") {
     |        s = "add"
     |        i
     |      } else {
     |        i += 1
     |        i
     |      }
     |    }
     | }
fo: ()() => Int

scala> val func1 = fo()
func1: () => Int = <function0>

scala> println(func1())
0

scala> println(func1())
1

scala> println(func1())
2

scala> println(func1())
3

scala> println(func1())
4