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From: Hubert HOLIN (Hubert.Holin_at_[hidden])
Date: 2002-11-14 09:14:49

Somewhere in the E.U., le 14/11/2002


                Thanks for the wonderfull reference!

                I would, of course, see octonions become part of the standard, but
there is currently a technical problem: The input operator is grossly
difficult to maintain.

                No sane implemetor (what does that mean for me? :-) ) would want to
ship an implementation such as the one I gave. There is a (wonderfully
elegant) way out of this problem: use Spirit (this is on my to-do list),
but this places a very significant standardization dependency.

                The problem is similar, but less accute, for quaternions.

                I believe the standard, in some future form, should also change the
complex specification to rely on an explicit (parseable) grammar. To
root the chain, I believe an explicit (parseable) grammar for floating
numbers and integers should at some point go in the standard as well.
This would not restrict the lattitude with wich compilers could find a
binary equivalent to a given explicit floating point constant, but would
be a step in the right direction with regard to explit constants (see
the discution on sclc++...).

                I would love to write a formal proposal for octonions, as well as for
quaternions, but for various reasons (getting my employer to understand
that would be time well spent, for instance), I now fear I risk missing
the boat...


                        Hubert Holin

"Paul A. Bristow" wrote:
> Ian Stewart, "The Missing Link...", New Scientist p 30, 9 Nov 2002 writes
> accessibly about Quaternions & Octonions:
> "The octonions started out as mathmetical curiosities, and were almost entirely
> ignored for 150 years, but their time has now come"
> so that I think these can be regarded as mainstream and entirely suitable for
> C++ Standard Library.
> Also references for further reading
> "The Octonions", John Baez, American Mathemtical Society, vol 39, p 145 (2002)
> Paul
> Paul A Bristow, Prizet Farmhouse, Kendal, Cumbria, LA8 8AB UK
> +44 1539 561830 Mobile +44 7714 33 02 04
> Mobile mailto:pabristow_at_[hidden]
> mailto:pbristow_at_[hidden]
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