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Re: Use of fragment identifiers in XML

From: Chris Lilley <chris@w3.org>
Date: Wed, 30 Oct 2002 21:46:47 +0100
Message-ID: <984481718.20021030214647@w3.org>
To: www-tag@w3.org, "Simon St.Laurent" <simonstl@simonstl.com>

On Tuesday, October 29, 2002, 10:42:11 PM, Simon wrote:

SSL> In the TAG minutes for the 28 October teleconference, I find this
SSL> exchange:
SSL> ------------------------------------------
SSL> 2.1.1 Use of fragment identifiers in XML

SSL>       * Action DC 2002/09/26: Describe this issue in more
SSL>         detail for the TAG

SSL>     CL: The fragments refer to elements.

SSL>     DC: Unclear from text of SVG spec (indicates that
SSL>     might be circle element or circle abstraction).

SSL>     CL: Please don't use SVG frags as an example of using
SSL>     a URI + frag to refer to an abstraction (circle).
SSL> ------------------------------------------

SSL> There isn't much context there, so I'm not entirely clear what the TAG
SSL> is considering,

I assert that in this SVG document toy.svg

<svg xmlns="http://www.w3.org/2000/svg">
 <circle r="2" id="foo"/>

that toy.svg#foo refers to a circle element.

Dan cites some wording in the SVG spec to the effect that no, this is
an example of pointing to an actual circle on screen, or the
mathematical definition of a circle, or the abstract notion of a
circle, or something.

I offered to clear up the loose wording in the spec as an erratum; Dan
was against that, presumably as fodder for the pointing-to-a-car line
of argument.  Myself, I find the whole argument akin to counting the
number of angels dancing on the head of a pin.

URIs point to Web resources. If people want to make derrived
assertions, of the form "I am talking about the car described on this
web page" then that is an arc, or an arcrole, or whatever - it is not
a property of the UIR, but an additional assertion that uses the URI
as part of its arguments. Both XLink and RDF have the concept of arcs
being separate from endpoints - I really don't see what the big deal
is here.

SSL> but this recent post of mine to uri@w3.org might be
SSL> relevant:

SSL> http://lists.w3.org/Archives/Public/uri/2002Oct/0027.html

SSL> URI references and fragment identifiers seem to have grown more
SSL> complex over the years, especially in XML contexts, and it seems
SSL> worthwhile at this point to discuss how they work once again.

Pointing to a bare id does not seem over complex to me. Your general
point is likely valid but the relevance to this example is not shown.

 Chris                            mailto:chris@w3.org
Received on Wednesday, 30 October 2002 15:46:48 UTC

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