alias F9 {
  var %birth.month = May
  var %birth.day = 13
  var %birth.year = 1988
  var %birth.time = 00:00:00
  var %i = $calc($ctime - $ctime(%birth.month %birth.day %birth.year %birth.time)), %j = $calc($ctime(%birth.month %birth.day $asctime(yyyy) %birth.time) - $ctime)
  if (%j < 0) { var %j = $calc($ctime(%birth.month %birth.day $calc($asctime(yyyy) +1) %birth.time) - $ctime) }
  var %age = $calc(%i / 3600 / 24 / 365.25))
  me is  $+ %age $+  years old, with a birthday in  $+ $datexpander($duration(%j,2),mwd) $+ 
}