Meng Wang wrote:
Hi Brian,
Thank you for starting the thread. We (Martin Sulzmann and me) proposed a type class extension which allows modular extension of superclasses (a complement of subclass extension). The idea has been shown to be particularly useful in (but not limited to) encodings of generic programming with type classes. A brief introduction of the proposal is documented in our wiki: http://taichi.ddns.comp.nus.edu.sg/taichiwiki/GPHomePage. I will try to add it as a link in yours soon.
A more detailed and formal description of the proposal can be found in our Workshop on Generic Programming 06 paper which is available at http://www.comp.nus.edu.sg/~sulzmann http://web.comlab.ox.ac.uk/oucl/work/meng.wang/
Thanks - I've added the above links to http://www.haskell.org/haskellwiki/Class_system_extension_proposal along with a one-line summary which I'm sure is totally imperfect but hopefully not too misleading ;-) Best regards, Brian. -- http://www.metamilk.com