W3C home > Mailing lists > Public > public-cdf@w3.org > January 2008

Re: xml:id

From: Henri Sivonen <hsivonen@iki.fi>
Date: Wed, 9 Jan 2008 12:07:14 +0200
Cc: Maciej Stachowiak <mjs@apple.com>, Timur Mehrvarz <timur.mehrvarz@web.de>, public-xml-core-wg@w3.org, public-cdf@w3.org, Eric Seidel <eric@webkit.org>
Message-Id: <44BA6D0D-B1D6-4E2E-B999-3CE4B53A107B@iki.fi>
To: daniel@veillard.com

On Jan 9, 2008, at 07:01, Daniel Veillard wrote:
> On Tue, Jan 08, 2008 at 03:25:32AM -0800, Maciej Stachowiak wrote:
>> On Jan 7, 2008, at 4:18 PM, Timur Mehrvarz wrote:
>>
>>> Are you really suggesting for authors to duplicate id and xml:id, in
>>> order to cope with this?
>>
>> I can't speak for Henri, but I would suggest authors use only id in
>> SVG content, and not xml:id, since id is more compatible and xml:id
>> offers no advantages for publicly deployed web content.

I'm not sure who "you" in the question referred to, but I agree with  
Maciej.

> Do SVG implementation actually parse/handle the DTD embedded in Web
> documents ?

They don't generally.

> I doubt it, in that case you rely on hardcoded behaviour of the  
> engine,

You don't need to rely on SVG engine-level hardcoding if you move the  
hardcoding layer (at least conceptually) to between the XML processor  
and the DOM builder. After all, that's were you'd put an xml:id  
Processor.

> and in my opinion it's better to rely on a low level hardcoded  
> behaviour (basically xml:id is an hardcoded DTD bypass)
> than one coming from upper layers which are less generic and  
> sometimes can be conflicting.

I'm suggesting putting the IDness assignment exactly on the level of  
lowness you'd put the xml:id Processor.

> What you are suggesting may be better from a code behaviour  
> viewpoint *now* but from an user data point of view,
> generic processing, long term management of those, it sounds safer  
> to use an ID handled at the XML level,

xml:id isn't on the XML level. It is immediately on one level above  
the XML level. I'm suggesting assigning IDness to id in no namespace  
(possibly making a grandfathered exception for CML elements) on the  
level where the xml:id spec specifies assigning IDness to id in the http://www.w3.org/XML/1998/namespace 
. What I'm suggesting is exactly as low or high level as xml:id.

> and since DTD processing is not guaranteed xml:id should be the most  
> reliable option.

That's a false dichotomy.

> There is certainly Web engine which don't recognize xml:id now, but  
> if the web content is targetting reuse and long lifetime I would  
> avoid relying just on the SVG hardcoded behaviour.

Considering long life time, browsers can never stop supporting the  
IDness of id in no namespace on XHTML, MathML and SVG elements.

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Wednesday, 9 January 2008 10:07:34 GMT

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