ios - How to better structure the functions in this script so that it will continue looping without a crash? -

my program update time each second, , using core graphics hours, minutes , seconds drawn out using shapes in uiview created in storyboard. when have script set in xcode, @ibdesignable aspect updates appropriate hour time in storyboard. below uiview subclass associated uiview in storyboard.

import uikit  @ibdesignable  class clock: uiview {     func updatetime() -> (hour:int, minute:int, second:int) {          var date:nsdate = nsdate()         var calendar:nscalendar = nscalendar.currentcalendar()         var components:nsdatecomponents = calendar.components(nscalendarunit.calendarunithour | nscalendarunit.calendarunitminute | nscalendarunit.calendarunitsecond, fromdate: date)          var hour = components.hour         var minute = components.minute         var second = components.second         setneedsdisplay()         return (hour, minute, second)           }      var timer = nstimer.scheduledtimerwithtimeinterval(0.1, target: self, selector: "updatetime", userinfo: nil, repeats: true)      override func drawrect(rect: cgrect) {          var hour = updatetime(hour)           switch hour {          case 0:              clockstylekit.drawcanvas0()          case 01, 13:             clockstylekit.drawcanvas0()             clockstylekit.drawcanvas01()          case 02, 14:             clockstylekit.drawcanvas0()             clockstylekit.drawcanvas01()             clockstylekit.drawcanvas02()      }  } 

when crashes, culprit line:

var hour = updatetime() 

it throws error says

variable used within own initial value.

any ideas? how can better structure continue updating time?