RE: [opengoop] Virtual Methods (Abstraction)

[Jim K. <ji...@ji...>]

Jean-Pierre,

First, thanks for the summary of the example.  I will add some notes =
from
your email to the page containing the OpenGOOP Inheritance example.

>=20
> Like class type inheritance refnums, child datatype will=20
> coerce (upcast) to parent datatype but not the reverse. If=20
> data is accessible as a variant (root data), all classes in=20
> the lineage can explicitely downcast the data to its class=20
> data using "Variant to Data" with error detection at run=20
> time. This would considerably ease the data access (the root=20
> object can create the dataspace (a variant for everybody) and=20
> no dynamic call to ancestor to get the data.
>=20
> I'll let you think about this for the moment....
>=20

Yes, it only took a moment to see that this is a very natural solution.  =
I
have created a page for this called "Data Type Inheritance Cluster" and
posted an example VI there that is derived from the Class Type =
Inheritance
Refnum example.  This page is located at:
<http://www.openg.org/tiki/tiki-index.php?page=3DData+Type+Inheritance+Cl=
uster
>

There is also a link to this page from the "OpenG Fwk: OpenGOOP =
Inheritance
Feasibility" page:
<http://www.openg.org/tiki/tiki-index.php?page=3DOpenG+Fwk%3A+OpenGOOP+In=
herit
ance+Feasibility>

-Jim