xml:id [was: MEETING MINUTES -- 19 Apr 2005 -- DITA TECHNICAL COMMITTEE]

["Paul Grosso" <pgrosso@arbortext.com>]

 > -----Original Message-----
> From: Larsen, Seraphim L [mailto:seraphim.l.larsen@intel.com] 
> Sent: Tuesday, 19 April, 2005 11:12
> To: dita@lists.oasis-open.org
> Subject: [dita] MEETING MINUTES -- 19 Apr 2005 -- DITA 
> TECHNICAL COMMITTEE
> 
> MEETING MINUTES -- 19 Apr 2005 -- DITA TECHNICAL COMMITTEE

>         - Issue 31 -- Side-by-side implementation of xml:id?
>                 - I couldn't capture the discussion.
>                 - Let's keep it on the list for 1.1 and keep
>                   discussing it.

Here's my explanation/discussion.

The W3C is developing a Recommendation that defines
the (reserved) attribute named xml:id to be of type "id"
even in the absence of any DTD or other schema.  The
idea is to make it easier to have ids in well-formed
XML documents (even if there is no schema).

Since DITA documents will generally be processed under
the influence of a schema, the use of xml:id may not be
needed.  However, if the use of xml:id becomes widespread
practice, in several years, users may expect to be able
to use xml:id to put an id on elements.  Furthermore, 
there may be certain processes where DITA content is
processed in the absence of any schema, and using xml:id
could be useful in this situation.

It is a validity error in XML for an element to have
more than one attribute on it whose type is "id".
The xml:id spec makes it an error to declare xml:id
to have any type other than "id".  Therefore, if we
were to add xml:id as an attribute on topic, we would
have to change the type of the existing id attribute
to be NMTOKEN (that is, we could not leave it as ID).

Michael didn't think that changing the type of the
existing id attribute to NMTOKEN would be much of
a problem.  I defer to him in this determination.

If we changed id to NMTOKEN and added xml:id to the
topic element type declaration in DITA 1.1, we might
have a fairly smooth transition path to using xml:id.

If we think we'll ever want to transition to xml:id,
I think doing it sooner (i.e., in DITA 1.1) is better.

paul