Rounding on output

[Kent M. Pitman <kmp at MIT-MC>]

With one exception, I have no special opinions about rounding on output
and will take whatever is given. The exception is that the rounding 
should be defined to always produce a valid number, even if in some cases
that means violating the normal rounding rule once in a while. In Maclisp,
the largest flonum (octal 377777,,777777) can be typed in by 1.70141182e+38
but will type out as 1.70141183e+38, which cannot be re-read because it gives 
a numeric overflow error. I can't decide if this is relevant to ~G, etc. or
just to general PRIN1, but figured this was as good a time as any to mention
it...