[PPL-devel] Another big change [Was: Documenting the classes PolyBase, Polyhedron and NNC_Polyhedron.]

[P M Hill]

On Wed, 27 Mar 2002, Roberto Bagnara wrote:

> Enea Zaffanella wrote:
> > However, as things are now, almost all the methods are defined only
> > in PolyBase and barely inherited by the two derived classes.
>
> This fact should probably bring us to the next big change,
> which should go as follows:
>
> 1) Rename Polyhedron to C_Polyhedron (from Closed Polyhedron).
> 2) Rename PolyBase to Polyhedron.
>
> Now C_Polyhedron and NNC_Polyhedron are just two varieties of
> Polyhedron, and we should probably insist they inherit _everything_
> from Polyhedron (this means, e.g., implementing is_topologically_closed()
> in Polyhedron so that it does the right thing).

I know, I am far removed from the centre of things and don't hear all the
reasons for why we do things as we do...
But, it looks to me from here strange that we need this NNC_Polyhedron as
a separate class from Polyhedron (was PolyBase).
I had thought that the reason for having PolyBase was that it was in some
way more general than an NNC_Polyhedron, but reading this, it is not so
clear to me anymore. If a Polyhderon is not necessarily closed, it can be
any Polyhedron?? On the other hand, a C_Polyhedron sounds like a subclass
of the (NNC_)Polyhedron.

ciao,
  Pat