some_more_combinators.scala

  def natural = rep1(single_digit) ^^ (_.mkString.toInt) named ("natural")

  def signedInt = new Parser[Int] {
    def apply(in: Input) = {
      '-'(in) match {
        case Success(_, rest) => natural(rest) map (_ * -1)
        case _ => natural(in)
      }
    }
  } named ("signed_int")

  def rawbyte = new Parser[Byte] {
    def apply(in: Input) = {
      if (in.atEnd) Failure("End of input reached", in)
      else Success(in.first, in.rest)
    }
  } named ("raw_bytes")

  def string: Parser[BString] =
    natural ~ ':' >> {
      case size ~ _ => repN(size, rawbyte) ^^ (BString(_))
    } named ("string")

  def int: Parser[BInt] = {
    delimitedBy(NUMBER_BEGIN, NUMBER_END)(signedInt) ^^ (BInt(_)) named ("int")
  }