| From: Thomas Bushnell BSG <xxxxxx@becket.net>
 | Date: Fri, 21 Oct 2005 18:22:45 -0700
 |
 | Aubrey Jaffer <xxxxxx@alum.mit.edu> writes:
 |
 | > I think that an implementation should be allowed to signal an
 | > error under some conditions where an error object is encountered.
 | > Mandating readable written representations for error objects
 | > prevents an implementation from signaling such errors.
 |
 | I think this might be confused.  Surely the mandating of a
 | representation would mean "if you print something (rather than
 | signalling an error) you should print it such-and-such a way."

That still prevents an implementation from displaying information
about what type of NaN was returned.  Such information could be
helpful to find the call which generated the NaN.

R*RS have so far constrained only output which was readable.  That
policy allows an implementation to present debugging info in results
without making every object first class.