package sbt
object Util
{
def separateE[A,B](ps: Seq[Either[A,B]]): (Seq[A], Seq[B]) =
separate(ps)(Types.idFun)
def separate[T,A,B](ps: Seq[T])(f: T => Either[A,B]): (Seq[A], Seq[B]) =
{
val (a,b) = ((Nil: Seq[A], Nil: Seq[B]) /: ps)( (xs, y) => prependEither(xs, f(y)) )
(a.reverse, b.reverse)
}
def prependEither[A,B](acc: (Seq[A], Seq[B]), next: Either[A,B]): (Seq[A], Seq[B]) =
next match
{
case Left(l) => (l +: acc._1, acc._2)
case Right(r) => (acc._1, r +: acc._2)
}
def counted(prefix: String, single: String, plural: String, count: Int): Option[String] =
count match
{
case 0 => None
case 1 => Some("1 " + prefix + single)
case x => Some(x.toString + " " + prefix + plural)
}
def pairID[A,B] = (a: A, b: B) => (a,b)
}