A little shortcut around always having to specify Left or Right

either-shortcut.scala

implicit def aToEither[A,B](a: A): Either[A, B] = Left(a)
implicit def bToEither[A,B](b: B): Either[A, B] = Right(b)

def f(input: Either[String, Int]) = input match {
  case Left(s) => println(s"Hello, $s")
  case Right(i) => println(s"You are $i years old")
}

scala> f(10)
You are 10 years old