Mike> Perl 6.0 is going to include even more drastic changes. It will Mike> also include a Perl 5.x interpreter, and will have to be switched Mike> to 6.0 mode by a magic cookie of some kind in the source. Possibly Mike> Python 3.0 could do something similar.
-1 Things are complex enough as it is. Maintaining two interpreters that have to somehow comingle would be worse. Maintain Python 2.x as a separate release for a period of time after Python 3.0 is released (a couple years, anyway, maybe longer), but don't mix the two. Skip -- http://mail.python.org/mailman/listinfo/python-list