Statement from HTML WG

Mon Sep 20 18:00:35 BST 1999

> The only place where the distinction between using one namespace and
> using three is important is when including fragments of xhtml in
> another document.

The distinction is important whenever one uses a namespace aware (rather
than XML 1.0) application. 3 namespaces makes querying into xhtml
documents with xpath (and thus with xslt) vastly more complicated.
The same would be true of any other XML namespace based application.

> However, in a fragment such as the following:
>
>              <notes>
>                <p xmlns='http://www.w3.org/TR/xhtml1/strict'>
>                    This is also available
>                        <a href="http://www.w3.org/">online</a>. 
>                </p>
>              </notes>

This really is the strangest claim. When importing an html p element
into the document type for notes, it is clear that (almost always)
you will want the paragraphs to contain inline elements from the
current document type as well as, or instead of, elements from html.
Thus the differences in the content model between a p in the 3 xhtml
DTD is _completely_ irrelevant, as the content model of this p will be
something else again. What is needed is

  <p xmlns='http://www.w3.org/html'>

No `strict' no `1' version number  This much is essential and
(possibly) no `x' either.

> The HTML WG opted for three namespaces on the grounds that one
> namespace makes one of the classes of use-case impossible, whereas
> three namespaces allows both, only making one of the classes harder to
> do.

Using one namespace does not make distinguishing between strict and
transitional impossible, it just means that you can't use the namespace
to do it, you have to use some more obvious system like having an
attribute that gives a url to the schema in use.

> However, the HTML WG is not bound irrevocably to three namespaces. We
> want XHTML to be a good XML citizen, and if the consensus of the XML
> community is that the 3-namespace use-cases are not important and can
> reasonably be ignored, we are willing to go with that consensus.

I am sure you will find that the consensus of the community is that
1 namespace should be used _and_ that the use-cases that need to
distinguish the DTD being used _are_ important (but that they should not
be distinguished by namespace)

Apart from this 1 v 3 argument there is still the worrying question not
really answered in the current drafts as to why xhtml is being specified
in a way incompatible with the namespace REC, which would make
<html xmlns="http://www.w3.org/html"> and
<css:html xmlns:css="http://www.w3.org/html">
equivalent, but the xhtml draft only acknowledges the validity of the
former?

David

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