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Re: ACTION: MarkB to email TF with his bnode proposal

From: Steven Pemberton <steven.pemberton@cwi.nl>
Date: Tue, 26 Apr 2005 17:19:49 +0200
To: "Mark Birbeck" <mark.birbeck@x-port.net>, public-rdf-in-xhtml-tf@w3.org
Cc: "'HTML WG'" <w3c-html-wg@w3.org>
Message-ID: <op.spuh7brqsmjzpq@r600.lan>

On Wed, 13 Apr 2005 16:01:38 +0200, Mark Birbeck <mark.birbeck@x-port.net>  
wrote:

Let me see if I understand.

 From this comment:

> NOTE: For this to work, we need to be able to distinguish between @href
> pointing to an anonymous node, and @href pointing to a named node when
> serialising. However, I think this is possible, and in fact, the only  
> check
> you need to do is whether an @id exists with that name. If there is no  
> @id,
> then we serialise as normal, even if there is no @about with that @id.

I understand that we use hrefs with fragments to identify bnodes when  
there is no actual element with that name, and if there is a element, then  
it identifies the node itself.

So to do the _:a foaf:knows _:b example, we would have

	<link about="#_a" rel="foaf:mailbox" href="mailto:steven@w3.org"/>
	<link about="#_b" rel="foaf:mailbox" href="mailto:mark@xport.net"/>
	<link about="#_a" rel="foaf:knows" href="#_b"/>

and if and only if there are no elements with id="_a" and id="_b" it  
refers to bnodes.

And so

	<meta about="#section1" rel="dc:creator">Ben Adida</meta>
	...
	<div id="section1">
	...

says that someone called "Ben Adida" created the element with id section1.

Did I get that right?

If so, then I don't see that it breaks anything. The only danger is that  
someone inadvertantly adds an element with an id that matches something  
that is meant to be a bnode, so they would have to be careful about naming  
(such as using an underscore as the first character).

But I do have a problem with the following statement:

> NOTE; We'd need to decide whether @id and @about can exist on the same
> element. At first sight it looks like it would be best if they didn't.

I don't see why, and I would strongly object to such a requirement. id is  
allowed anywhere in XHTML for a reason, and there are good reasons why  
both should be allowed on an element.

Steven
Received on Tuesday, 26 April 2005 15:19:57 GMT

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