> So, anyone have any ideas what NaN would be useful for? Especially given
> we have NULL available, which most (non DB) numeric applications don't.
Hmm. With Tom Lane's new fmgr interface, you *can* return NULL if you
spot a NaN result. Maybe that is the best way to go about it; we'll
stipulate that NaN and NULL are equivalent. And we'll further stipulate
that if you are messing with NaN then you deserve what you get ;)
- Thomas