a couple of “run time parsing and rewriting” ideas for ruby:

1) inline methods.  Not too hard, right?

2) if you’ve got

def go(a)

 if a.is_a? Array

   # stuff

 else

   # other stuff

 end

end

then you “could” wrap go, determine its inputs, then rewrite it as

def go_a_as_array(a)

  stuff

end

and call it appropriately.