Re: [opengoop] Virtual Methods (Abstraction)

[Jean-Pierre D. <jea...@tr...>]

Jim,

I did not mean clustered child data. I can't see why it doesn't work with=
out cluster. What's that link/duplicate thing?

Jean-Pierre

----- Message d'origine -----=20
De : "Jim Kring" <ji...@ji...>
=C0 : <ope...@li...>
Envoy=E9 : 13 octobre, 2003 02:58
Objet : RE: [opengoop] Virtual Methods (Abstraction)


Jean-Pierre,

The example that I posted to the "Data Type Inheritance Cluster" page won=
't
work.  In order to work the class data should be in its own cluster.  I
believe that the structure needs to look like the following:

object:  variant
base: {{base data}, variant}
child: {{base data}, {{child data}, variant}}.
and so on

Instead of:

> object:  variant
> base: {base data, variant}
> child: {base data, {child data, variant}}.
> and so on

I'm sure you meant that "base data" and "child data" are in fact clusters=
,
but I didn't interpret it that way initially.  Having class data in a
cluster separate from the variant is necessary for a descendant to link t=
o
an ancestor's data store (rather than duplicating it).

I have posted a new "Example - Data Type Inheritance Cluster Coercion" at=
:
<http://www.openg.org/tiki/tiki-index.php?page=3DData+Type+Inheritance+Cl=
uster
>

This new example uses a class hierarchy from an OOP example (sent to me
privately by Niels Harre), which graphs geometric objects to a picture
control.

-Jim