withExtendedLifetimes (arbitrary number of parameters)

gistfile1.swift

// You call this as:
//   withExtendedLifetimes([x,y,z]) { ... }
// I haven't been able to replace the array with variadic. The function
// will be absorbed into the list (even if it's curried).
func withExtendedLifetimes(args: [Any], f: () -> ()) {
  var rest = args
  let last:Any = rest.removeLast()
  if rest.count > 0 {
    Swift.withExtendedLifetime(last) { () -> () in withExtendedLifetimes(rest, f) }
  }
  else {
    Swift.withExtendedLifetime(last, f)
  }
}

////////

// But don't discount the other approach which doesn't require the extra array
// (in the spirit of withUnsafePointers):

// To get rid of the `() -> () in` casting
func withExtendedLifetime<T>(x: T, f: () -> ()) {
  return Swift.withExtendedLifetime(x, f)
}

func withExtendedLifetimes<A0, A1>(arg0: A0, arg1: A1, f: () -> ()) {
  return withExtendedLifetime(arg0) { withExtendedLifetime(arg1, f) }
}

func withExtendedLifetimes<A0, A1, A2>(arg0: A0, arg1: A1, arg2: A2, f: () -> ()) {
  return withExtendedLifetime(arg0) { withExtendedLifetimes(arg1, arg2, f) }
}

// ... however more you want ...