anchor.diff:                                              | _ -> []
                                           ) 
                                           |> ExprArray
  +                                    | SpecialHole -> <@ [||] @>
                                       | a -> <@ [| %(getSimpleHole a.Value) |] @>
   
                                   if isRoot then 
  
positive.code:                                                 %nodes :> _ @>
                                          else failwithf "data-var attribute \"%s\" on invalid element \"%s\"" a.Value n
  
                              | a -> getSimpleHole a.Value
                          
                          let mainExpr = t |> createNode true
  
negative.code:     let dataVar = xn"data-var"
      let dataAttr = xn"data-attr"
      let dataEvent = "data-event-"
      let (|SpecialHole|_|) (a: XAttribute) =
          match a.Value.ToLowerInvariant() with
          | "scripts" | "meta" | "styles" -> Some()
          | _ -> None
  
      do
          this.Disposing.Add <| fun _ ->
  