Localizable views in xib or storyboards

LocalizableButton.swift

import UIKit

/// Implements a UIButton that can be localized within a xib or storyboard.
/// To render a localized string set a “User defined runtime attribute” on 
/// the view with a key path of `localizableStringKey` and a string value of 
/// the localized string key.
class LocalizableButton: UIButton {
    
    var localizableStringKey: String? {
        didSet {
            if let key = localizableStringKey {
                let string = LocStr(key)
                setTitle(string, forState: .Normal)
            }
        }
    }

}

LocalizableLabel.swift

import UIKit

/// Implements a UILabel that can be localized within a xib or storyboard.
/// To render a localized string set a “User defined runtime attribute” on
/// the view with a key path of `localizableStringKey` and a string value of
/// the localized string key.
class LocalizableLabel: UILabel {
    
    var localizableStringKey: String? {
        didSet {
            if let key = localizableStringKey {
                text = LocStr(key)
            }
        }
    }
    
}

trying out the suggestion here: http://stackoverflow.com/a/7413783/123781

Of course we could just use Base Internationalization but I wanted to get a feel for how this method worked.