Your point? You said that someone should look to these systems as cases of "metaprogramming". Now you say that they are "metaprogrammable". You seem to have

Your point? You said that someone should look to these systems as cases of "metaprogramming". Now you say that they are "metaprogrammable". You seem to have a very specific notion of metaprogramming, what exactly would you consider to be a prototypical use of it?