why distinctions within XHTML?

Simon St.Laurent simonstl at simonstl.com
Mon Aug 30 19:25:22 BST 1999

At 05:57 PM 8/30/99 +0100, Mark Bireck wrote:
>But what if you wanted to write an editor that left MathML alone, or
>passed the MathML parts on to another application or plug-in? You'd need
>to use XML Schemas because DTDs couldn't handle that (your XHTML doc has
>just failed if it has MathML in it!) and you'll need a namespace for
>that (under current proposals). So, if you accept that you need three
>DTDs, then to get into the world of XML Schemas (or whatever it ends up
>being) you need three namespaces.

If it was clear that XML schemas would be using such a mechanism to connect
schema information to documents, I'd agree with this argument, though it
doesn't justify 3 DTDs in the first place.  However, so far as I know, no
such suggestion has been made in any official way.  The namespaces remain
only identifiers, not connectors to a particular schema.  The XHTML PR
doesn't even include the word 'schema', period.  (Surprising but true!)

On top of which, it isn't clear yet how XHTML will combine with other
schemas, like MathML - which I'd very much like to see explicitly stated.
Section 3.1.2 states:

>The XHTML 1.0 namespace may be used with other XML namespaces as 
>per [XMLNAMES], although such documents are not strictly conforming 
>XHTML 1.0 documents as defined above. Future work by W3C will address 
>ways to specify conformance for documents involving multiple namespaces.

I don't think we've gotten to the point where we have a clear understanding
of the relationship between namespaces and processing, which seems to have
been a deliberate decision in the creation of XML Namespaces.  Should the
W3C develop such an understanding (and publish it), we might then have
grounds for a rational decision.

Instead, complexity seems to get squared with every new conversation, as
new possibilities and different interpretations emerged.  3 namespaces to
me looks like 9 times the complexity overall, but I'll happily admit that's
just a gut feeling.

Simon St.Laurent
XML: A Primer (2nd Ed - September)
Building XML Applications
Inside XML DTDs: Scientific and Technical
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