[R6RS] NaNs and infinities

[dyb at cs.indiana.edu]

> Anyway, the important part of of my statement was that there
> are no infinite integers in the current draft of SRFI 77.
> Although that blows your mind, I appreciate your endorsement
> of infinite reals in SRFI 77.

I said my peace but for the record it didn't include an endorsement
of infinite reals.  (Infinite extended reals are okay, but we don't
have an extended-real? predicate.)  (Or do we?  Maybe that's what
this mysterious real-valued? is.)

Kent