extract pair as expected type

fromScalaConsole.scala

trait CanFromString[T] {
  def fromString(s: String): T
}

implicit object intCanFromString extends CanFromString[Int] {
  override def fromString(s: String): Int = s.toInt
}
implicit object SymbolCanFromString extends CanFromString[Symbol] {
  override def fromString(s: String): Symbol = Symbol(s)
}

def pair[K: CanFromString, V: CanFromString](s: String, keyColumn: Int, valueColumn: Int): (K,V) = {
  val arr = s.split(",")
  implicitly[CanFromString[K]].fromString(arr(keyColumn)) -> implicitly[CanFromString[V]].fromString(arr(valueColumn))
}



assert(pair[Int, Symbol]("0001,notyy,37", 0, 1) == (1, 'notyy))