title: play framework: calling functions in routes file
body: <p>Is it possible to call functions in playframework routes file?.
  In the below example if the url path doesn't have instance_id in it, I will have to generate a new one (using <code>utils.Util.uuid</code> function) to assign it to the instance_id parameter.</p>
  
  <pre><code>POST  /job/instance/start/:jobName/:instanceId   @controllers.JobInstanceController.startInstance(jobName: String, instance_id: String = utils.Util.uuid, label: Option[String])
  </code></pre>