William D Clinger wrote:
> When I say that requiring only the fixnum/flonum foundation is
> an attractive option for R6RS, second only to requiring the
> full tower, I certainly do not mean to imply that systems
> would be forbidden to support numbers that are neither fixnum
> nor flonum.  In particular, I do not mean to suggest dropping
> the part of R5RS section 6.2.3 I quoted above.

I would say that R6RS has to provide arithmetic on exact integers that
are large enough to serve as indexes and lengths. So, either R6RS must
require that fixnums are large enough or it must provide routines to
perform arithmetic on integers that might be larger than fixnums.

Regards,

Alan
--
Dr Alan Watson
Centro de Radioastronomía y Astrofísica
Universidad Astronómico Nacional de México