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Re: XHTML Invalidity / WML2 / New XHTML 1.1 Attribute

From: Dan Connolly <connolly@w3.org>
Date: Sat, 12 Aug 2000 11:36:25 -0500
Message-ID: <39957D09.3B9E7915@w3.org>
To: Sean Palmer <sean_b_palmer@yahoo.com>
CC: www-html@w3.org, jrexon@newsguy.com, DJW@bts.co.uk, bertilow@hem.passagen.se
Sean Palmer wrote:
> 
> Dear All,
> 
> Once again, thanks for the great response.
> Contents
> 1) Individual replies to people
> 2) Comments in general (along with more replies!)
> 
> Re: Dan Connolly
> Thank you for taking time out to prepare these files
> for us - it certainly saves us the future task. Will
> the schema URI be permanent,

Yes, I expect it to be highly available (our servers
are mirrored around the world) at that address
for many years to come.

W3C has a policy that once we make something available
at some address, we service that address (possibly
by way of a redirection) forever.
	http://www.w3.org/Consortium/Persistence

> or should I copy it
> locally?

You may... lemme make that explicit...

OK... I added a copyright statement and open source
license terms:

http://www.w3.org/XML/2000/04schema-hacking/comment.xsd
$Revision: 1.3 $ of $Date: 2000/08/12 16:15:54 $

> Namespaces are certainly one way of doing it; however,
> it doesn't seem as if any provisions are being made to
> combine the Schema spec. with the (X)HTML spec. - i.e.
> it doesn't validate on the main XHTML validator.

Try again... the main validator has a limited understanding
of namespaces and schemas, at this time. In particular,
it only looked for namespace declarations on the first
line. I removed a linebreak, and you'll see that now
the validator reports

	"No errors found! "
http://validator.w3.org/check?uri=http://www.w3.org/XML/2000/04schema-hacking/comment-test.html


> For people's convenience, I added an XHTML DTD to the
> document at
> http://www.waptechinfo.com/comment_test_xhtml.html

You'll have to do more work if you want to use namespaces
with DTDs. The XHTML modularization spec supposedly
tells you how to do it, but it's pretty tedious.
I recommend you don't bother with DTDs, if you're
interested in mixing vocabularies.

> Having a util:comment attribute, however, is not the
> same as having a comment attribute, unless the Schema
> was universally recognised.

The schema is recognized by all systems that (a) implement
the XML Schema spec, and (b1) can use HTTP to find
schemas from namespace names or (b2) have this
particular schema cached or hardcoded.

> Maybe the W3C should come
> up with a library of Schema for people to use? (Such
> as the one you kindly prepared for us).

We have come up with a library: it's called the Web.
My 04schema-hacking stuff is (some of) my contribution
to the world wide library of XML schemas. The XML Schema WG
has contributed a piece too:
	http://www.w3.org/1999/XMLSchema
and I expect them to contribute more.

I have an incomplete index of schemas in the library at:
	http://www.w3.org/XML/Schema#usage




> Of course, we have Christian Smiths idea:-
> 
> <?BM_COMMENT
> <meta name="date" content="8/11/2000">
> <meta name="author" content="Chris Jones">
> <meta name="status" content="Review">
> <meta name="reference" content="bluemoon.gif>
> <meta name="comment" content=" The bluemoon.gif
> file is just a placeholder logo Maddy says Dave has a
> friend who does graphic design and he is going to do
> something fancy in exchange for some work he needs
> Dave to do (I'm not asking, I don't want to know " >
> ?>

Sigh... more ad-hock markup, not grounded in the web.

May I suggest:

<div style="display: none">
<web:RDF xmlns:web="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
         xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:util="mid:place-holder@example.org"
	xmlns:s="http://www.w3.org/2000/01/rdf-schema#">
  <web:Description about="bluemoon.gif"
	dc:date="2000-08-11"
	dc:creator="Chris Jones"
	util:status="Review"
	>
	<comment>The bluemoon.gif
 file is just a placeholder logo Maddy says Dave has a
 friend who does graphic design and he is going to do
 something fancy in exchange for some work he needs
 Dave to do (I'm not asking, I don't want to know 
	</comment>
  </web:Description>
</web:RDF>
</div>

As to the meaning of each bit of markup above, just
follow the namespace pointers and find out for yourself.


> But this would only work for small amounts of
> comments. If you had 50 elements in an XHTML document
> that needed commenting upon, you would end up with way
> too much META info, and confusion in this style.

That's when a stand-off system, ala the annotation
work that Karl alluded to, makes more sense.

> In
> the reference part, you would have to start using ID#
> instead of file names (which is bad practise anyway).
> 
> The idea that you provided earlier may be a little
> better:-
> 
> <!--
> <date>8/11/2000</date>

Blech. More ad-hoc markup syntax.
Good luck getting much tool support for that.
You'll have to build it all yourself.

> But we couldn't do an XSLT transform on this because
> it is commented out.

Exactly.

> Some browsers can't handle markup
> in a comment.

None, in my experience.

[...]
> My idea is simple, and it works well; of that
> I am now convinced. However, an extensible META
> language for comments only does sound promising; but
> we would still need to include this into the document
> by means of namespaces. We could write a whole new
> languge for this (METAML? or how about UTIL, as per
> Mr. Connolly)

We did just that:
	Resource Description Framework (RDF)
	http://www.w3.org/RDF/

> and declare a namespace for it and the
> DTD.

Using DTDs with namespace is awkard (though it
can be done; cf
http://www.w3.org/XML/9710rdf-dtd/ ).

I recommend using XML Schemas if you want
syntactic validation of XML documents.

> Then, we would just include parts of it into the
> document - encompassing the range of attributes that
> DJW talked about, and the Schemas that Mr. Connolly
> has provided.
> 
> SO, in conclusion, the best two ideas (in my humble
> opinion) are a comment attribute, or a completely new
> language. What say ye all?

I don't think we need anything new; XML, namespaces,
RDF, and XML Schemas should do nicely.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Saturday, 12 August 2000 12:37:14 GMT

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