test2

test2.scala

package org.test.uml

case class Object(name: String) {
  def --(message: String) = (this, message)
  def <--(message: String) = (this, message)
}
sealed trait Action
sealed case class Call(source: Object, verb: String, destination: Object) extends Action
sealed case class Async(source: Object, verb: String, destination: Object) extends Action

object implicits {
  class Sourceable(source: Object, action: String) {
    def -->(target: Object) = Call(source, action, target)
    def <--(target: Object) = Call(target, action, source)
  }
  implicit def toSourceable(tuple: (Object, String)) = new Sourceable(tuple._1, tuple._2)
}

object Uml {
  import implicits._
  def main(args: Array[String]): Unit = {
    val bob = Object("Bob")
    val dan = Object("Dan")
    println(List(
      bob -- "salutes" --> dan,
      dan -- "respondes" <-- bob
    ))
  }
}