where to put generics?

[Andy Wingo]

Hi again,

I figured while I was emailing I could get something else off my chest
-- what is the best way for two modules that do not want to know about
each other to add methods to the same generic? The problem there is that
such a generic might not exist in the 'stock' top-level environment. The
generic would need to be created and then exported, but only one time --
if both modules export generics, the generics from recent modules will
replace those from previous modules.

So, if the generics are only exported once, where should they be put?
I'm hacking around this for the moment by putting them in the root
module, but that's not exactly an elegant solution. What's the thought
on this? Has anyone else had to deal with these issues in the past?

Thanks again,

wingo.