gistfile1.scala

class Projection(source: Pipe, transformers: List[(Map[String, Any]) => (Map[String, Any])]) extends Traversable[Map[String, Any]] {
  def foreach[U](f: (Map[String, Any]) => U) {
    source.foreach((m) => {
      transformers.map((transformer) => transformer.apply(m)).reduceLeft(_ ++ _)
    })
  }
}