Pimping scala.collections

gistfile1.scala

implicit def iterable2Cross[T, C[T] <: Iterable[T]](tees: C[T]) = new {
  import collection.generic.CanBuildFrom

  def cross[S](esses: Iterable[S])(implicit cbf: CanBuildFrom[C[(T,S)],(T,S),C[(T,S)]]): C[(T,S)] = {
    val builder = cbf()

    val rst = for (t <- tees; s <- esses) yield (t, s)

    rst foreach { builder += }
    builder.result
  }
}