Tim Cook wrote:
> On Wed, 2008-05-07 at 18:04 +0100, Thomas Beale wrote:
>
>
>> this attribute is populated in memory when an archetype is deserialised,
>> so it points to the actual ARCHETYPE object. In almost every case (of
>> the few that there are) that there is a 'parent' reference, it works
>> like this.
>>
>
> Okay, so now my understanding is that; the attribute contains the
> parent archetype of this archetype? Not the current ("owner of this
> ontology") archetype (which is circular). That kind of clears that up.
>
no - it is the latter - the owner archetype. 'parent' was a poor choice
of name....
> But according to the AOM spec:
> "2.3.3 Archetype Specialisation
> ...
> reach them.
> "
>
> I originally read this to say that the specialization section was really
> for information and not an operational requirement for an archetype
> instance.
>
there is a whole new section in the forthcoming version 1.5 of ADL that
(finally;-) deals with specialisation semantics.
> However, from your explanation. It seems to me that an archetype
> instance with layers of specialization will require instances of all
> parents nested within. If this is true; what value are they at
> implementation?
>
in the archetype workbench we have implemented the idea of an 'archetype
lineage', i.e. specialisation trees of archetypes. Each specialised
archetype in the tree is in its 'differential' form, and also in its
'flat' generated form. Now, a confusing factor here in this is that the
current .adl files for specialised archetypes are in the flat form, i..e
they contain copies of inherited elements from parents. Clearly this is
not maintainable, so in the new generation of tools, .adls will be used
as the source files and these will be in differential form. For the
majority of archetypes that are not specialised, the result is the same.
The .adl files of the future will be generated from the .adls files; for
specialisation archetypes this is done by doing an
'inheritance-flattening' procedure. This is already implemented in a
basic way in the latest release of the Archetype Workbench.
Drafts of the new version of the ADL specification will be available as
soon as they are in a comprehensible form.
- thomas
