better solution for initial jump

lib/virtual/object.rb

@@ -3,7 +3,7 @@ require "parfait/message"
 
 module Positioned
   def position
-    raise "position accessed but not set at #{length} for #{self.inspect}" if @position == nil
+    raise "position accessed but not set at #{length} for #{self.inspect[0...500]}" if @position == nil
     @position
   end
   def set_position pos