anchor.diff:          do
               this.Text <- html
       end    
  +    
  +    // support for 303 Redirect
  +    type Http303(location:string) as this = class
  +        inherit Response(303,"text/html")
  +        do
  +            this.AddHeader("Location",location)
  +    end
  +
       type MyLock() = class 
           let x = 9
           do 
  
positive.code:     let explanation code =
          match code with
              | 200 -> "OK"
              | 404 -> "Not found"
              | 401 -> "Authorization required"
              | _ -> "unknown"
  
negative.code:     /// http page not found response
      let http404 text = Http404(text) :> Response
  
      /// http redirect
      let http303 location = Http303(location) :> Response
  
      /// helper for xml responses
      let xmlResp text = XMLResponse(text) :> Response
  
  