comparisons between floats and ratios

["Gail Zacharias" <GZ%OZ.AI.MIT.EDU@XX.LCS.MIT.EDU>]

Is (> a-rational a-float) supposed to err out when (float a-rational a-float)
would overflow?  If so, there should at least be some way to tell ahead of time
if that's going to happen, for people who want to write a more careful
comparison routine.  The only way I can figure out of doing this now is
(> a-ratio (rational most-positive-xx-float)).  Consing up a bignum
representation of the largest float seems like a high price to pay for being
careful.

Since most floating point implementations can (internally at least) represent
infinity, it shouldn't cause a great loss of efficiency to require that this
case return T. 

A not-entirely-unrelated question:  What kind of rounding is FLOAT supposed
to do?
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