Or.scala

trait Or[+A, +B]
case class LOr[+A, +B](a: A) extends Or[A, B]
case class ROr[+A, +B](b: B) extends Or[A, B]

implicit def lOr[A, B](implicit a: A): Or[A, B] = LOr[A, B](a)
implicit def rOr[A, B](implicit b: B): Or[A, B] = ROr[A, B](b)

def valueIsIntOrString[T](value: T)(implicit param: Or[T => String, T => Int]) = param match {
  case LOr(t2String) =>
    println("value is String") 
    println(t2String(value))
  case ROr(t2Int) =>
    println("value is Int")
    println(t2Int(value))
}

valueIsIntOrString(100)
valueIsIntOrString("Foo")
// valueIsIntOrString(1.0) // Compilation Error