Example 1:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | struct Example { let run: (Int) -> (String) // type declaration}extension Example { init(){ // define self.run = { i in return "good, " + String(i) } }}let e = Example() // e.run is definede.run(90) // e.run can be used |