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[Richard B. Kreckel]

Hi Bernard,

Sorry it took me so long to answer this but the changes in CLN 1.1 kept me
busy...

On Thu, 2 Nov 2000, Parisse Bernard wrote:
> > IMHO, users of GiNaC should not reply on the internal representation of
> > algebraic objects (even that op(nops()-1) thing is suspicious to me), because
> > that representation has changed, and will change sometime in the future.

Okay, it has changed and it will change sometime in the future.  But
still, I would argue that op(nops()-1) thing is trivial to guarantee and
should be guaranteed because it can be useful in times.

> > Extensions to GiNaC in the form of new classes, however, may benefit from
> > or even require access to the internal representation, in which case the
> > C++ "friend" mechanism can be used.
> 
> The main problem is however that the friend declaration must be
> present in GiNaC source code not in the extension source code.
> Anyway, I don't see any difference in accessing internal representation
> via a friend class or via members as soon as it is documented that
> these members might change in the future. I don't like bureaucraty!

Sure.  The other clean option would be that you provide us with a method
sitting in expariseq, add and mul which maps the object to a data
structure that you need and we'll simply put that into GiNaC.  Maybe this
is what should be done.

Regards
    -richy.
-- 
Richard Kreckel
<Richard.Kreckel at Uni-Mainz.DE>
<http://wwwthep.physik.uni-mainz.de/~kreckel/>