[question] Usage of return

[franklinchou]

One question I had was what if you explicitly want control flow to return to the calling function?

For example, in a web controller function I have the following:

def index(): Action[AnyContent] = Action.async { implicit rq: Request[AnyContent] => 
  rq.getQueryString("permission-field") match {
    case Some(pf) => 
      if (!permissioned.contains(pf)) return Action(Forbidden)
      else // do other stuff
    case None => 
      Future { BadRequest }
  }
}

[Slakah]

In your example, you would need to return something in the else block. If you wanted to reduce nesting, you could move the permission check into the pattern match, i.e.

def index(): Action[AnyContent] = Action.async { implicit rq: Request[AnyContent] => 
  rq.getQueryString("permission-field") match {
    case Some(pf) if (!permissioned.contains(pf)) => Action(Forbidden)
    case Some(pf) => 
      // do other stuff
    case None => 
      Future { BadRequest }
  }
}

I would also quote from the guide.

Besides, return is anti structural programming, as functions can be described with multiple exit points and if you need return, like in those gigantic methods with lots of if/else branches, the presence of a return is a clear signal that the code stinks, a magnet for future bugs and is thus in urgent need of refactoring.