NextIteration.scala

for (
  file <- inputFiles
  if file.isFile
) {
  val lines = scala.io.Source.fromFile(file).getLines().toList

  def grepScalaFrom(ln: Int): Unit = {
    if (ln >= lines.length) -1
    else {
      if (lines(ln).matches(".*scala.*")) println(file+", "+(ln+1)+": "+lines(ln).trim)
      grepScalaFrom(ln + 1)
    }
  }

  grepScalaFrom(0)
}