local Position Xs N NP L in
   fun {Position Xs N}
      local XT XH in
         case XH|XT = Xs of XH|nil then
            if XH == N then 1 end
         [] XH|XT then 1+{Position XT N}
         end
      end
   end

   NP = 3
   L = [1 2 3]
   {Browse {Position L NP}}

end