I'd like to announce the existence of Multimethod.py, a package that implements real (eg, CLOS/Cecil/Dylan) multimethods for Python. These are nifty for oodles of reasons, but some of the more significant are: o They make the Visitor and Strategy patterns trivial to implement. o The whole "binary method/double dispatch" problem goes away, thus promoting loose coupling and other software-engineering buzzwords. o They resolve the whole contravariance/covariance debate so totally it's hard to remember what the problem was. You can find it on my webpage at: <URI:http://www.sff.net/people/neelk/open-source> It should work out of the box on CPython 1.5.2, and Jpython if Jpython has lists that support the insert() method. I don't know about Viper, since Viper apparently has a rather different type system from vanilla Python, but it should be easy to port, though. The current version is quite rough, with lame algorithms used in a couple of places and very substandard documentation. But it all works, and is quite usable for experimentation and learning. (Incidentally, is this the sort of thing that should go on the types-sig?) Neel <P><A HREF="http://www.sff.net/people/neelk/open-source">Multimethod.py</A> - support for real (i.e. CLOS/Cecil/Dylan-style) multimethods for Python. (07-Jan-2000) -- ----------- comp.lang.python.announce (moderated) ---------- Article Submission Address: python-announce@python.org Python Language Home Page: http://www.python.org/ Python Quick Help Index: http://www.python.org/Help.html ------------------------------------------------------------