digits.Swift

extension IntegerType {
  func digits() -> [Self] {
    var runner = self
    return anyGenerator {
      defer { runner /= 10 }
      return runner == 0 ? nil : runner % 10
    }.reverse()
  }
  func digits(base: Self) -> [Self] {
    var runner = self
    return anyGenerator {
      defer { runner /= base }
      return runner == 0 ? nil : runner % base
    }.reverse()
  }
}

extension SequenceType {
  func chunk(n: Int) -> AnyGenerator<[Generator.Element]> {
    var (g, count) = (self.generate(), n + 1)
    let innerGen = anyGenerator{ count++ == n ? nil : g.next() }
    return anyGenerator {
      count -= (n + 1)
      guard count == 0 else {return nil}
      let ar = Array(innerGen)
      guard !ar.isEmpty else {return nil}
      return ar
    }
  }
}