UIView.loadFromNib().swift

import UIKit

/// Protocol to be extended with implementations
protocol UIViewLoading {}

/// Extend UIView to declare that it includes nib loading functionality
extension UIView : UIViewLoading {}

/// Protocol implementation
extension UIViewLoading where Self : UIView {
  
  /**
   Creates a new instance of the class on which this method is invoked,
   instantiated from a nib of the given name. If no nib name is given
   then a nib with the name of the class is used.
   
   - parameter nibNameOrNil: The name of the nib to instantiate from, or
   nil to indicate the nib with the name of the class should be used.
   
   - returns: A new instance of the class, loaded from a nib.
   */
  static func loadFromNib(nibNameOrNil: String? = nil) -> Self {
    let nibName = nibNameOrNil ?? self.className
    let nib = UINib(nibName: nibName, bundle: nil)
    return nib.instantiateWithOwner(self, options: nil).first as! Self
  }
  
  static private var className: String {
    let className = "\(self)"
    let components = className.characters.split{$0 == "."}.map ( String.init )
    return components.last!
  }
  
}