Step.scala

    def parseParams(path:String):Map[String,Array[String]] = {
      for {
        pair <- path.split('/').toList.tail.zipWithIndex.filter(part => placeholders.exists(place => part._2 == place))
      } yield (parts(pair._2) -> Array(pair._1))
    }

//[error] /Users/alan/Projects/scala/step/./src/main/scala/Step.scala:34: type mismatch;
//[error]  found   : List[(String, Array[String])]
//[error]  required: Map[String,Array[String]]
//[error]         pair <- path.split('/').toList.tail.zipWithIndex.filter(part => placeholders.exists(place => part._2 == place))
//[error]         ^
//[error] one error found