W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > January 1997

Re: [dgd@cs.bu.edu: BOS confusion (analysis; suggestion to resolve Newcomb/Bryan conflict)]

From: Martin Bryan <mtbryan@sgml.u-net.com>
Date: Fri, 03 Jan 1997 09:53:12 +0000
Message-Id: <>
To: dgd@cs.bu.edu (David G. Durand), w3c-sgml-wg@www10.w3.org

>>.... URLs that are not backed up by entity declarations
>>will still work just fine in the same way that they already do in HTML
>>-- in one direction only.  (However, if you want applications to be
>>aware of the fact that an object is the anchor of some particular
>>external link, you do have to declare where the application should
>>look for that external link.)
>Yes, I do. I want to separate that process from link creation entirely,
>because I don't see that they are closely related. My other point about
>URLs is that I think we are foolish if we make an important facility like
>this depend on the use of entity declarations -- most current users will
>find this indirection quite onerous. In fact, _I_ think that it is onerous
>for some kinds of simple document reference.

The point is that if we are using HyTime links then we need an entity
declaration that can be used to name the link source for a chain of links
(we don't want to repeat the same 1024 character URL hundreds of times, we
want to give it an id in a well controlled namespace). This is how HyTime
works. That entity declaration will contain the URL of the page we want. If
you have links to more than one point in that page this method is more
efficient than having to respecify the URL on each link. (Otherwise there is
an unnecessary overhead.) If the same URL is referenced by multiple
documents it should be stored in a subhub BOS that can be referenced by all
documents that refer to it. Seems to me that this helps URL management
greatly. This is the real bugbear of existing web applications.

> That means _no  mandatory entity declarations_ in the
>definition of linking.

But this would make the use of link sources for link chains impossible. Link
chains are one of the real gains that HyTime has to offer. If we drop them
from XML we are dead. Without a formally defined sources in the BOS you
cannot have a start point for the chain.
Martin Bryan, The SGML Centre, Churchdown, Glos. GL3 2PU, UK 
Phone/Fax: +44 1452 714029   WWW home page: http://www.u-net.com/~sgml/
Received on Friday, 3 January 1997 04:54:56 UTC

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