Swift stuff

I started with Swift recently. So this is going to be the place I put all the gotchas, tricks and everything including complains

• Private functions are private:
  This:

  self.addTarget(self, action: Selector("valueChanged"), forControlEvents:.ValueChanged)
  
  private func valueChanged() { ... }
  

  Leads to: unrecognized selector sent to instance the function must not be private.

  func valueChanged() { ... }
  

• Downcasting:
  These two are basically equal. (cell is an UITableCellView). In objc there is no problem accessing nil stuff. It is a NOP, has good and bad sides. In swift it must be explicitly declared and accessing nils leads to crashes.
  

  // objc
  [[cell viewWithTag:102] setText:@”Something”];
  
  //or something syntaxly closer to below swift code
  ((UILabel *)[cell viewWithTag:102]).text = @”Something”;
  

  // swift
  (cell.viewWithTag(102) as? UILabel)?.text = “Something”
  
  // to refer `label` more than once create a variable and access its methods if not nil
  if let label = cell.viewWithTag(102) as? UILabel {
      label.text = “Something”
  }