Re: arithmetic issues William D Clinger (18 Jan 2006 18:29 UTC)
Re: arithmetic issues Alan Watson (18 Jan 2006 18:53 UTC)
Re: arithmetic issues Alan Watson (18 Jan 2006 19:05 UTC)

Re: arithmetic issues Alan Watson 18 Jan 2006 19:05 UTC

William D Clinger wrote:
> In either case, I think flonums should be in the base
> language, because most hardware now supports them much
> more efficiently than they could be implemented in a
> library module.

I disagree.

Let me give a counter example. I could write an implementation in which
flonums are a basic type but flonum operations are not exposed in the
base language. That is, in the base language, the standard arithmetic
procedures (and probably the procedures that convert to and from
external representations) would signal an error if asked to operate on
flonums.

I could then implement a library module for the full tower, including
flonums. Of course, I would not be able to implement the library module
efficiently in the base language, but as I'm the implementor that is not
a real problem -- I define the extensions I need and make them available
to the library module.

So, it is possible to have an efficient implementation of flonums in the
library without forcing them to be exposed in the base language.

Regards,

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