encodePair.scala

encodePair.scala

def encodePair(pair: (Char, Char)): (Char, Char) = findLetterInSquare(pair._1) match {
  case (a, b) => findLetterInSquare(pair._2) match {
    case (`a`, `b`) => throw new Exception("UNPOSSIBLE!") // same cell
    case (`a`,  d ) => (indexToLetter((a, (b+1)%5)), indexToLetter((a, (d+1)%5))) // same row
    case ( c,  `b`) => (indexToLetter(((a + 1)%5, b)), indexToLetter(((c+1)%5, b))) // same column
    case ( c,   d ) => (indexToLetter((a, d)),indexToLetter((c, b)))
  }
}