Scala hieroglyph experiments

arrows.scala

import language.{postfixOps,implicitConversions}
case class -->[A, B] (from: A, to: B)
implicit class ArrowSugar[A](private val self: A) { def --> [B] (other: B) = new -->(self, other)}

def diff(arrow: Int-->Int) = arrow match {
  case x --> y => y - x
}

diff(1 --> 4) should be (3)

def buildMap[A,B](items: A-->B*) = items map {case (x --> y) => (x, y)} toMap

buildMap('2' --> "two", '5' --> "five") should be(Map(('2', "two"), ('5', "five")))