Re: [xtm-wg] Editors Alert: scopes on association roles.

["Nikita Ogievetsky" <nogievet@cogx.com>]

Steve,

Thanks, I am glad you agreed.

(I do not want to argue with some of your comments
and recollections because it is not important right now.)

Thanks,

Nikita.

-------------------------------------------
Nikita Ogievetsky                  Cogitech Inc
XML/XSLT/XLink/TopicMaps Consultant
nogievet@cogx.com   --   (917) 406-8734
http://www.cogx.com     Cogito Ergo XML

----- Original Message -----
From: Steve Pepper <pepper@ontopia.net>
To: <xtm-wg@yahoogroups.com>
Sent: Friday, February 09, 2001 2:54 AM
Subject: Re: [xtm-wg] Editors Alert: scopes on association roles.


> At 22:48 08/02/01 -0500, Nikita Ogievetsky wrote:
> >It came to my attention that F.3.2 says:
> >(as I was revisiting F.3.3 :-))
> >
> >"4. Either the Class or Instance roles are in a scope other than the
unconstrained scope. "
> >
> >I think this line should be removed because there is no scopes on
association roles.
> >It must be a leftover from the old DTD.
>
> It isn't incorrect, but it could be slightly confusing.
>
> It is, in fact, the *roles* that are scoped, as the conceptual
> model clearly states (see B.5 and B.8, but note that there is
> a typo in the current version of B.8: "membership" should read
> "role").
>
> This is also as we have always said:
>
>    "A topic has three kinds of characteristic: names,
>     occurrences, and *roles* played in associations."
>
>    "Scope expresses the limits of the validity of a
>     topic characteristic assignment.")
>
> However, *in the syntax* there is a constraint that all roles
> in the same association have to be in the same scope. This is
> enforced by having the <scope> element be a child of the
> <association> element rather than the <member> element. (See
> the note on B.8 in Annex B.) Again, this constraint is something
> that was discussed and decided in Dallas.
>
> So as it stands F.3.2 is not wrong in the way you think.
>
> Having said that, there *is* something wrong with that fourth
> condition in F.3.2, which is that it seems to forbid the use
> of scoping on class-instance associations altogether. This
> was not my intent, and I plan to clear it up with Graham today.
>
> For me, <instanceOf> is a useful -- but less powerful --
> alternative to using a class-instance association. The reason
> I say it is less powerful is precisely because you cannot
> express scope when using <instanceOf>. We've known this all
> along, and it's OK. <instanceOf> is syntactic sugar for the most
> common case. But that is no reason to hamstring the mechanism
> used to express the more general case.
>
> I will be suggesting to Graham that we add the words "in the
> unconstrained scope" after the word "association" in the second
> para of F.3.2, and that we remove the fourth error condition.
>
> Steve
>
> --
> Steve Pepper, Chief Technology Officer <pepper@ontopia.net>
> Convenor, ISO/IEC JTC1/SC34/WG3  Editor, XTM (XML Topic Maps)
> Ontopia AS, Maridalsveien 99B, N-0461 Oslo, Norway.
> http://www.ontopia.net/  phone: +47-22805465  GSM: +47-90827246
>
>
>
> To Post a message, send it to:   xtm-wg@eGroups.com
>
> To Unsubscribe, send a blank message to: xtm-wg-unsubscribe@eGroups.com
>
>
>




------------------------ Yahoo! Groups Sponsor ---------------------~-~>
eGroups is now Yahoo! Groups
Click here for more details
http://click.egroups.com/1/11231/0/_/337252/_/981791763/
---------------------------------------------------------------------_->

To Post a message, send it to:   xtm-wg@eGroups.com

To Unsubscribe, send a blank message to: xtm-wg-unsubscribe@eGroups.com