Felipe Lessa wrote: > On Sun, Jun 13, 2010 at 01:09:24PM +0100, Andrew Coppin wrote: > >> Does anybody have a less-insane way of doing this? >> > > Did you take a look at happstack-ixset[1]? > No. I'll take a look at it. (From the looks of it, it seems to be using TH and/or run-time checks to get around the type-system problems...)