[QUANTITY] Data Model for Quantity v0.5

[David Berry]

Pierre,

> Well! it depends of the point of view.
> Speaking of human species, starting from neolithic up to nowdays,
> something like that occurs, and it is not evident if a jet fighter
> project starting ab nihilo would have succed in any achievement.
> We may be need a bicycle first, and once we understand everything on the subject
> we can try a car, and then go on.
> Moreover, people needing only bicycle are then not force to use a jet.
> I am deeply in favour of a very pragmatic bicycle.
> I am really afraid by the lunar rocket style of the actual quantity model,

I think we are not starting from nothing, or anywhere near nothing. There
are already developed systems in regular use around the world which are
similar to the proposed Quantity model. It must surely make sense to
build on the existing experience rather than throwing it all away and
starting back at the "bicycle" stage. You never reach the aircraft
stage if you keep on throwing away previous experience.

> and I certainly don't understand half of the document.

This is the first problem to address. If people do not understand the
document, it will be difficult to get useful discussion on the model
itself. Comments welcome...

> Does people who would use these data types (data providers/VO actors...?)
> feel confortable with this very complex construction?

If not, we need to know what specific aspects of the document or model
are causing concern. Then we can attempt to clarify or simplify them.

> The only thing, I think is promising (imho) is to forgot the implementation
> (no mention of the data structure in term of data member or class attributes)
> and concentrate on interface and method definition, leaving implementation
> free and adjustable to the needs of any intervening party.

Agreed.

David

----------------------------------------------------------------------
Dr David S. Berry    (dsb at ast.man.ac.uk)

STARLINK project		 |	Centre for Astrophysics
(http://www.starlink.ac.uk/)	 |	University of Central Lancashire
Rutherford Appleton Laboratory	 |	PRESTON
DIDCOT				 |	United Kingdom
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