Another look at namespaces

Simon St.Laurent simonstl at simonstl.com
Thu Sep 16 20:21:05 BST 1999


At 01:05 PM 9/16/99 -0500, Shane P. McCarron wrote (a better answer than I
hoped to receive):
>"Simon St.Laurent" wrote:
>> Is there _anything_ else besides their names that distinguishes these
flavors?
>
>Sure.
>
>XHTML Frameset has a completely different content model than the other
>two. Its root element is html, but that html element may NOT contain a
>body element. Instead, it contains a frameset element that defines the
>collection of frames. These frames have some weird inherent behaviour
>that cannot be described by existing schema technology (various panels
>are defined in the window, one per defined frame). To be clear, an XHTML
>Frameset document as NO CONTENT.  Instead, it refers to content.  Is
>this stupid?  Sure. However, it is a faithful representation of HTML
>4.0.

The question in full was 'Is there anything else besides [the DTDs 
- from prev para - and ] their names that distinguishes these flavors.

'Completely different content model' is still well within the realm of
DTDs/schemas.  'Weird inherent behavior' at least moves beyond that, but
I'm not sure it justifies an additional namespace.

>XHTML Transitional has a different content model than Strict in that it
>is more permissive.  XHTML Transitional may be a superset of XHTML
>Strict, but I have never done the evaluation to be certain. I am certain
>that they are significantly different. In particular, XHTML Transitional
>contains all sorts of stuff that is eliminated in XHTML 1.1. XHTML
>Strict only has a few items that are removed in XHTML 1.1 (e.g. the name
>attribute on the a element is eliminated in favor of the id attribute).

This is all represented by the DTD, however - I don't think there's any
need to go beyond that and distinguish strict from transitional as far as
identifiers are concerned.

>> >Information about those namespaces may, if the W3C chooses to follow this
>> >path, be obtained from a schema, DTD, or other data source at the end of
>> >that URI.
>> 
>> Or, since this is an XML 1.0 application, you could just read the DOCTYPE
>> declaration and not try to map namespace URIs to places where the W3C might
>> (but won't comment on publicly at present) want to go someday.
>
>Absolutely. And, since XHTML 1.0 requires a DOCTYPE declaration, you can
>be confident that one will be present in XHTML 1.0-conforming documents.
>Moving forward, as the HTML Working Group completes its work on Document
>and Client profiles (which might just be requirements to CC/PP, who
>knows), I expect that the group will define elements that allow document
>authors specify:
>
>	a pointer to a document profile
>	a complete, embedded document profile
>	information about the schema
>	information about how the schema is based upon other, well known 
>		schema (like XHTML)
>	etc.
>
>However, that is a future problem. The current problem is finding a way
>through this morass so that we can publish the first baby step toward a
>better, more interoperable web. That is XHTML 1.0.  What do we need to
>do to get on with it?

Simplify would be a good first step.  Give XHTML 1.0 a single namespace for
this version, and then get on with the more exciting work that follows.
Don't complicate matters by adding namespaces on top of the DOCTYPE
declaration you promise to use faithfully.

But remember, I haven't paid any membership dues.


Simon St.Laurent
XML: A Primer (2nd Ed - September)
Building XML Applications
Inside XML DTDs: Scientific and Technical
Sharing Bandwidth / Cookies
http://www.simonstl.com

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