W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > December 1996

Re: anchor awareness (was Re: Richer & richer semantics?)

From: Tim Bray <tbray@textuality.com>
Date: Sat, 21 Dec 1996 17:51:31 -0800
Message-Id: <>
To: w3c-sgml-wg@www10.w3.org
I think that Steve was making an important point, but I think that I
didn't really get it.  So this is a request for amplification, with some 

>The question is:
>"Does an anchor know that it is an anchor?"

What does it mean for an anchor to know it's an anchor... and I guess,
what exactly are you terming an anchor?  Consider the following:

Example 1: http://www.textuality.com/sgml-erb/mprdv.html

not as an example, but in and of itself, embedded in the email you
are now reading.  I would assume this is not an anchor in the sense that you
mean; 1-way www semantics make it a link-end but not an anchor.  The person 
who placed mprdv.html at www.textuality.com and sent the URL out by email 
was consciously creating an anchor that in some sense knows it's an anchor
since there is an httpd server that will give anyone a copy, no questions

On the other hand, when 

Example 2: <A NAME="sec3.17"> 

appears in an HTML document, I assume you would call this an anchor that 
knows it's an anchor?  It exists only to provide addressing hooks.

Some form of the same argument could be applied to any element with an
attribute that has been declared to be of type ID?

On the other hand, (Example 3: ) with some analogue of ilink, where you can 
point into a document from outside using locaddrs or some such, you clearly
have a case that what's being pointed-at does not and cannot in principle
know it's an anchor... or am I missing your point?

>The answers to lots of important questions depend on the answer to the
>above question, including:
>"Can an n-ended link be n-directional?"  ( n >= 2, of course )

Huh? It is not obvious to me why this depends on anchor-self-knowledge.

>On the one hand, if we say that anchors must be aware of their
>anchorishness even when the links that confer anchor status upon them
>are elsewhere, a many-headed Hydra monster arises.

This seems waaaaaaay outside our scope.

>On the other hand, if (as in HTML) we say that all linking is
>unidirectional and all links have two ends, the starting end of which
>is where the link is, XML does not offer any functional improvement,
>in hyper terms, over HTML.

Can we not have multiway ilink-style thingies and perhaps even a
modest amount of locaddr and so on, without getting into major
paradigm re-engineering?  This is the key point - I had asserted that
an ilink thing, particularly if you restrict to addressing by entity
& ID attribute, was a low-hanging fruit that was easy to understand,
easy to implement, and clearly better than today's HTML.  Are you saying
that (a) this is a can of worms, or that (b) it is not in fact better,
or (c) have I just missed the whole point?

Cheers, Tim Bray
tbray@textuality.com http://www.textuality.com/ +1-604-488-1167
Received on Saturday, 21 December 1996 20:52:40 UTC

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