Re: XML:ID extension spec proposal to HTML5 documents

Doug Schepers, Wed, 05 Feb 2014 14:26:05 -0500:
> Hi, Leif–
> 
> xml:id was well-intentioned, but poorly designed. It tries to solve 
> the problem in the wrong layer.
> 
> Since you referenced SVG, I thought I'd chime in with some history I 
> thought might help. We removed xml:id from SVG because it created 
> identity conflicts, led to confusing authoring guidelines, and was 
> generally disruptive to existing content formats like SVG and HTML. I 
> researched this and wrote it up [1] for the SVG WG.

Thanks. I did in fact read that writeup of yours in the autumn. No 
doubt did it give me valuable insights. 

> If XInclude UAs or other parts of the XML toolchain want to recognize 
> the ID-ness of HTML, SVG, or MathML, those tools should simply be 
> updated to use the same building blocks of the Web Stack that other 
> tools are shifting to. There are far fewer of those tools than there 
> are authoring tools or authors. Don't ask the dog to be wagged by the 
> long tail.

I think the correct way to put it would be to say that if xml tools 
wants to support/recognize HTML5, then they should assign IDness the 
way it is done in HTML5. (But it is perhaps more valuable to talk the 
issue …)

> (In my opinion, XML should simply have defined @id to be of type ID 
> from the beginning,

Another way to say that ID-ness should have been separated from XML 
validity, from the start.

> or done so later instead of working on xm:id; the 
> only major XML language that didn't conform to the @id-uniqueness 
> best practice was Chemical Markup Language (CML), and they should 
> simply have chosen a different attribute name.)

In principle the XML ID assignment mechanism is also an i18n feature 
(as it allows to assign ID-ness to e.g. абвæøå="foo").  I wonder if 
there are examples of XML languages that have made of use it that 
aspect of it?

Leif Halvard Silli


> [1] http://www.schepers.cc/xmlid/svgxmlid.html

> 
> Regards-
> -Doug
> 
> On 1/31/14 5:48 PM, Leif Halvard Silli wrote:
>> Jirka Kosek, Fri, 31 Jan 2014 22:19:34 +0100:
>>> On 31.1.2014 8:09, Leif Halvard Silli wrote:
>>>> The extension spec addresses the issue that the new doctype that was
>>>> introduced by HTML5, removed (classic) XML ID-type assignment from HTML
>>>> documents consumed as XML. As a result, XML tools relying on that kind
>>>> of assignment are unable to locate resources of XML ID type in HTML5
>>>> documents. XHTML1 documents do not have this issue (as long at their
>>>> DOCTYPE is included).
>>> 
>>> It seems that your motivation is solely based on making it possible to
>>> use xpointer in XInclude for HTML content. Then I think right approach
>>> is to define that when XInclude is evaluated on text/html content, then
>>> id attribute is considered of ID type and you are done. There is no need
>>> to clutter HTML5 with xml:id attribute.
>> 
>> Of course, it would be very handy if it was as simple to use HTML5
>> documents with XInclude as it is to use XHML1.x documents. And since
>> the spec is about ”XML ID-type assignment“ for HTML5 documents (see the
>> title), a future update could add the kind of mechanism that you
>> suggest.
>> 
>> But as of right now, I am unaware of tools that have taken that
>> approach. It does not even seem to work for SVG (please correct me!) -
>> and least not when it come XML tools. (And this despite the fact that
>> SVG is a format for which the approach you recommend ha been talked
>> about for a while.)
>> 
>> Using HTML as format for all kinds of documents, is increasingly
>> popular. Thus my attitude is that there is a need for a document that
>> specifies what exists and works today.
>> 
> 
>

Received on Wednesday, 5 February 2014 19:55:25 UTC