gee, I just read what I wrote and it borders on nonsense (I don't
exactly think in words, so its not alwasy easy to translate) BUt to
explain better:

     struct object {
     |
     | fields.each{|f| field f}
     |
     };

change marker, becomes:

     struct object {
     #
     # fields.each{|f| field f}
     #
     };

invert:

     #struct object {
       fields.each{|f| field f}
     #};

So, using this setup a normal ruby program would run while printing out
it's comments. Not useful, but I just thought it was interesting.