FunctorsTweaks.scala

// apply optional tweak: Option[Tweak[_]]
def large(implicit ctx: Context): Option[Tweak[TextView]] = hdpi ? TextSize.large
myTextView ~> large

// apply a list of tweaks: List[Tweak[_]]
myButton ~> List(text("The red button"), id(Id.redButton))

// functional reactive programming: Rx[Tweak[_]]
val caption = rx.Var("Olá")
myTextView ~> caption.map(c ⇒ text(c)) // sets text to “Olá”
caption.update("Adeus") // text automatically updates to “Adeus”

// apply tweak to a list of widgets: List[View] ~> Tweak[_]
List(myButton, myTextView) ~> hide

// apply optional tweak to a list of widgets: List[View] ~> Option[Tweak[_]]
List(myButton, myTextView) ~> (hdpi ? hide)