The rdoc for the Comparable module and its methods consistently indicate 
that the <=> method must return values -1, 0, or +1. But the 
implementation consistently tests for values < 0, == 0 and > 0.
See compar.c in the source tree.

I believe that this is a documentation bug, and I will submit a patch if 
folks here agree with me.  Shouldn't we be allowed to write our <=> 
operators so that they return any Numeric value?

	David Flanagan