anchor.diff:      let WindowProxyType = Class "Window"
       let MessagePortType = Class "MessagePort"
   
  +
  +
       let MessageEvent =
           Class "MessageEvent"
           // |=> Implements [T<Event>]
  +        |+> Static [
  +            Constructor (T<string> * !?T<obj>)
  +        ]
           |+> Instance [
               "data" =? T<obj>
               "origin" =? T<string>
  
positive.code:             "font" =@ T<string>
              "textAlign" =@ TextAlign
              "textBaseline" =@ TextBaseline
  
              "fillText" => T<string> * T<float> * T<float> ^-> T<unit>
              "fillText" => T<string> * T<float> * T<float> * T<float> ^-> T<unit>
  
negative.code:               // updates
              "update" => T<unit> ^-> T<unit>
              "swapCache" => T<unit> ^-> T<unit>
              "abort" => T<unit> ^-> T<unit>
  
              // events
              ///  Function onchecking;
  