Subject: Re: The role of media types for XML content
From: Chris Lilley <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: Mark Baker <[email-masked]>, [email-masked]
Date: Thu, 16 Jun 2005 02:01:51 +0200
List-Id: <ietf-xml-mime.imc.org>

On Thursday, June 16, 2005, 1:35:09 AM, MURATA wrote:

Chris>> With respect, you are, since I pointed one out in this thread. You may
Chris>> disagree with it, but you are not unaware of it. I have already
Chris>> mentioned content negotiation of schemas and the problems caused by
Chris>> serving both RNG and XSD as application/xml.

MM> Yes, of course.  You pointed out the problem.  

MM> Chris, Mark, and Martin think that an attribute indicating media types
MM> is very useful for standalone schemas and are inclined to forget
MM> embedded schemas for now.

Or at least, to say that reliably identifying a standalone schema does
not necessarily constrain any future solution for embedded ones.

MM>   I think that an attribute specifying primary
MM> namespaces, for example, is more useful and it works for standalone
MM> schemas as well as embedded schemas.

Possibly; a mere list is not really quite sufficient, as the xslt
template shows. Nesting order is also important.

MM>  I also think that the use of media
MM> types by the referrer should be avoided, since they may be different
MM> from what the server says.

Which has been looked at by the TAG and found to be consistent with Web
Architecture as long as it is treated as a fetching hint and not defined
to be authoritative over what the server sends, in the very few cases
where that turns out to be different.

-- 
 Chris Lilley                    mailto:[email-masked]
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead

Date: Thu, 16 Jun 2005 08:35:09 +0900
From: MURATA Makoto <[email-masked]>
To: Chris Lilley <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: Mark Baker <[email-masked]>, [email-masked]
Sender: [email-masked]

Chris> With respect, you are, since I pointed one out in this thread. You may
Chris> disagree with it, but you are not unaware of it. I have already
Chris> mentioned content negotiation of schemas and the problems caused by
Chris> serving both RNG and XSD as application/xml.

Yes, of course.  You pointed out the problem.  

Chris, Mark, and Martin think that an attribute indicating media types 
is very useful for standalone schemas and are inclined to forget
embedded schemas for now.  I think that an attribute specifying primary 
namespaces, for example, is more useful and it works for standalone
schemas as well as embedded schemas.  I also think that the use of media
types by the referrer should be avoided, since they may be different
from what the server says.

Cheers,

-- 
MURATA Makoto <[email-masked]>

Date: Wed, 15 Jun 2005 20:31:16 +0200
From: Chris Lilley <[email-masked]>
Reply-To: Chris Lilley <[email-masked]>
Organization: W3C
To: MURATA Makoto <[email-masked]>
Cc: Mark Baker <[email-masked]>, [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Wednesday, June 15, 2005, 8:22:17 PM, MURATA wrote:

Mark>> but for now though, I agree with Liam and Martin

and Chris :)

Mark>> that a new media type makes the most sense.

MM> Here we do not agree.  I think that the advantages of specialized 
MM> media types are rather minor.  I am not aware of any complaints 
MM> about the lack of specialized media types for W3C XML Schema.

With respect, you are, since I pointed one out in this thread. You may
disagree with it, but you are not unaware of it. I have already
mentioned content negotiation of schemas and the problems caused by
serving both RNG and XSD as application/xml.

-- 
 Chris Lilley                    mailto:[email-masked]
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead

Date: Thu, 16 Jun 2005 03:22:17 +0900
From: MURATA Makoto <[email-masked]>
To: Mark Baker <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Mark,

Mark> I agree with your premise that a new media type for each new XML
Mark> vocabulary is not a scalable, long-term solution.  But neither do I
Mark> think that application/xml is a solution.  

Here we agree.  (I suppose you meant application/xml combined with namespace
sniffing.)

Mark> The work being done in the
Mark> CDF WG may provide one, 

I think that a long-term solution is badly needed and 
that it is likely to be different from media types.

Mark> but for now though, I agree with Liam and
Mark> Martin that a new media type makes the most sense.

Here we do not agree.  I think that the advantages of specialized 
media types are rather minor.  I am not aware of any complaints 
about the lack of specialized media types for W3C XML Schema.

Cheers,

-- 
MURATA Makoto <[email-masked]>

Date: Wed, 15 Jun 2005 20:16:45 +0200
From: Chris Lilley <[email-masked]>
Reply-To: Chris Lilley <[email-masked]>
Organization: W3C
To: MURATA Makoto <[email-masked]>
Cc: Liam Quin <[email-masked]>, [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Wednesday, June 15, 2005, 8:01:56 PM, MURATA wrote:

Liam>> 
Liam>> > Then, why doesn't W3C register specialized media types for XSLT or
Liam>> > W3C XML Schema?  Is there some consensus in W3C?
Liam>> 
Liam>> XSLT - I think application/xslt+xml is either registered or the
Liam>> registration will be sent here for XSLT 2.

MM> It is not registered at IANA.

It is not *yet* registered (since it is not a Recommendation), but is in
process. Please see
http://www.w3.org/2002/06/registering-mediatype.html#Status

and
http://www.w3.org/2002/06/registering-mediatype.html#Planned

-- 
 Chris Lilley                    mailto:[email-masked]
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead

Date: Thu, 16 Jun 2005 03:01:56 +0900
From: MURATA Makoto <[email-masked]>
To: Liam Quin <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Liam> 
Liam> > Then, why doesn't W3C register specialized media types for XSLT or 
Liam> > W3C XML Schema?  Is there some consensus in W3C?
Liam> 
Liam> XSLT - I think application/xslt+xml is either registered or the
Liam> registration will be sent here for XSLT 2.

It is not registered at IANA.

Cheers,
-- 
MURATA Makoto <[email-masked]>

Date: Wed, 15 Jun 2005 12:50:02 -0400
From: Mark Baker <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Tue, Jun 14, 2005 at 11:47:40PM +0900, MURATA Makoto wrote:
> Mark> >And do you want to specify a 
> Mark> > specialized media type when you reference the embedded RNG?
> Mark> 
> Mark> Ideally, yes, I think that would be valuable for the reasons I gave
> Mark> before concerning layering and security.
> Mark> 
> Mark>  [1] http://www.w3.org/2004/CDF/
> Mark>  [2] http://www.markbaker.ca/2004/01/XmlDispatchTest/
> 
> You propose to use a specialized media type for a fragment and 
> to use a different media type for the entire resource.

Ah, I misunderstood you.  I thought you were referring to a separate
media type for the embedded RNG itself, not for use by the referrer to
that RNG.  I wouldn't encourage the referrer to use a separate media
type since it violates the principle that the server provided media type
be authoritative in determining fragment identifier.

I agree with your premise that a new media type for each new XML
vocabulary is not a scalable, long-term solution.  But neither do I
think that application/xml is a solution.  The work being done in the
CDF WG may provide one, but for now though, I agree with Liam and
Martin that a new media type makes the most sense.

Mark.
-- 
Mark Baker.  Ottawa, Ontario, CANADA.          http://www.markbaker.ca
Coactus; Web-inspired integration strategies   http://www.coactus.com

Date: Wed, 15 Jun 2005 12:05:08 -0400
From: Liam Quin <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Wed, Jun 15, 2005 at 09:45:04AM +0900, MURATA Makoto wrote:
> Liam> I'd like to see a registration for the XML syntax simply because
> Liam> it's useful today, despite the limitations.
> 
> Then, why doesn't W3C register specialized media types for XSLT or 
> W3C XML Schema?  Is there some consensus in W3C?

XSLT - I think application/xslt+xml is either registered or the
registration will be sent here for XSLT 2.  I don't know the status
for Schema offhand -- we're getting better, slowly :-)

> Anyway, we can do nothing about a specialized media type for the RNG 
> XML syntax by November.
Understood.  Thanks for the reply.

Liam

-- 
Liam Quin, W3C XML Activity Lead, http://www.w3.org/People/Quin/
http://www.holoweb.net/~liam/

Date: Wed, 15 Jun 2005 07:53:14 -0400
From: "John.Cowan" <[email-masked]>
To: Martin Duerst <[email-masked]>
Cc: Liam Quin <[email-masked]>, MURATA Makoto <[email-masked]>, [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

Martin Duerst scripsit:

> Also, Relax NG in XML syntax most probably may have provisions
> of some sort about how to include other namespaces, e.g. for
> documentation,...

Indeed, arbitrary elements and attributes may appear in a RELAX NG document,
provided they are in a namespace other than the RNG namespace.  There is
no specific wrapper element as there is in W3C XML Schema.

The RNG documentation indeed provides for a documentation namespace
as well as a namespace for recording DTD-specific information in order
to make it possible to roundtrip DTDs through RNG.

-- 
"Well, I'm back."  --Sam        John Cowan <[email-masked]>

Date: Wed, 15 Jun 2005 09:32:49 +0900
To: Liam Quin <[email-masked]>, MURATA Makoto <[email-masked]>
From: Martin Duerst <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

At 08:59 05/06/15, Liam Quin wrote:

 >But that should not stop us from using the existing infrastructure as
 >best and as helpfully as we can in the meantime.
 >
 >I'd like to see a registration for the XML syntax simply because
 >it's useful today, despite the limitations.

I fully agree with Liam. I think the argument against registering
a type for the XML syntax was based on the question "but what about
pieces of this in another XML document?". Creating a type for a
standalone Relax NG document in XML syntax, which allows people
to label such documents if they can, does not exclude the use
of Relax NG in XML syntax as part of other documents.

Also, Relax NG in XML syntax most probably may have provisions
of some sort about how to include other namespaces, e.g. for
documentation,...

Regards,    Martin. 

Date: Wed, 15 Jun 2005 09:45:04 +0900
From: MURATA Makoto <[email-masked]>
To: Liam Quin <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Liam> I'd like to see a registration for the XML syntax simply because
Liam> it's useful today, despite the limitations.

Then, why doesn't W3C register specialized media types for XSLT or 
W3C XML Schema?  Is there some consensus in W3C?

Anyway, we can do nothing about a specialized media type for the RNG 
XML syntax by November.

Cheers,
-- 
MURATA Makoto <[email-masked]>

Date: Tue, 14 Jun 2005 19:59:47 -0400
From: Liam Quin <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Wed, Jun 15, 2005 at 08:06:36AM +0900, MURATA Makoto wrote:
[...]
> I have said that specialized media types for XML-based vocabularies are 
> ad-hoc solutions which do not work for multi-namespace documents
Here I agree with you.  The architectures clearly don't match at all:
Internet media types simply don't work for this sort of document today.
Mozilla Firefox is making this clear -- it supports XHTML with
embedded MathML and SVG for example, in either order, and perhaps
with XHTML and SVG and mathML inside the SVG...

> and that proliferation of specialized media types blocks future use 
> of multi-namespace documents.
I don't think it's blocking future use.  I think in the long term we
have to rethink how multi-namespace XML documents are handled.

But that should not stop us from using the existing infrastructure as
best and as helpfully as we can in the meantime.

I'd like to see a registration for the XML syntax simply because
it's useful today, despite the limitations.

Best,

Liam

-- 
Liam Quin, W3C XML Activity Lead, http://www.w3.org/People/Quin/
http://www.holoweb.net/~liam/

Date: Wed, 15 Jun 2005 08:06:36 +0900
From: MURATA Makoto <[email-masked]>
To: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

Chris> 
Chris> MM> However, unless such significant changes are endorsed, I continue 
Chris> MM> to be very reluctant to register a specialized media type for 
Chris> MM> the RELAX NG XML syntax.
Chris> 
Chris> I don't see how the issue of how/whether to point to a portion of an xml
Chris> resource which happens to be in RNG, has *any* bearing on the issue of
Chris> what media type to use when RNG is served as a stand-alone document,
Chris> which is by far the typical case at the moment. There is no dependency
Chris> there.

I have said that specialized media types for XML-based vocabularies are 
ad-hoc solutions which do not work for multi-namespace documents and
that proliferation of specialized media types blocks future use 
of multi-namespace documents.  I thus see strong dependency.

Chris> MM> After all, it is ISO/IEC JTC1/SC34 that is requesting the
Chris> MM> registartion of a media type for the RELAX NG compact syntax. In its
Chris> MM> last meeting, SC34 decided to request this media type, but did not
Chris> MM> consider a specialized media type for the RELAX NG XML syntax.
Chris> 
Chris> 
Chris> So, now I am asking them to consider it. Will you convey this request to
Chris> them, or do I need to convey it by a more formal mechanism?

I can formally raise this issue in the next SC34 meeting in November and
can also informally contact SC34 members now.  However, between now and
Novembmer, SC34 WG1 can do nothing.  ISO/IEC JTC1 has no mechanisms for
making decisions other than formal meetings.

Chris> MM>  Since we are talking about
Chris> MM> media types in the standard tree, the media type for the RNG compact
Chris> MM> syntax can go to the IESG but that for the RNG XML syntax cannot.
Chris> 
Chris> I don't follow your last point there.

As far as a specialized media type for the RNG XML syntax in the
standard tree is concerned, nothing can be done before November.

Cheers,

-- 
MURATA Makoto <[email-masked]>

Date: Tue, 14 Jun 2005 17:40:33 +0200
From: Chris Lilley <[email-masked]>
Reply-To: Chris Lilley <[email-masked]>
Organization: W3C
To: MURATA Makoto <[email-masked]>
Cc: Mark Baker <[email-masked]>, [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

On Tuesday, June 14, 2005, 4:47:40 PM, MURATA wrote:

Mark>> >And do you want to specify a 
Mark>> > specialized media type when you reference the embedded RNG?
Mark>> 
Mark>> Ideally, yes, I think that would be valuable for the reasons I gave
Mark>> before concerning layering and security.
Mark>> 
Mark>>  [1] http://www.w3.org/2004/CDF/
Mark>>  [2] http://www.markbaker.ca/2004/01/XmlDispatchTest/

MM> You propose to use a specialized media type for a fragment and 
MM> to use a different media type for the entire resource.  It is a very
MM> interesting idea.  It might help the marriage between media types and
MM> multi-namespace XML documents.  But I do not think that MIME RFCs or
MM> URI/IRI RFCs bless it (at least now).  Media types have been intended
MM> as values of the content-type field of MIME.  

MM> You might want to raise this issue in the W3C CDF WG or W3C TAG, and
MM> you might even want to write an RFC that updates MIME RFCs or URI/IRI
MM> RFCs.

his is interesting, and speculative, future work. However, and not
distracting from the original specific issue:

MM> However, unless such significant changes are endorsed, I continue 
MM> to be very reluctant to register a specialized media type for 
MM> the RELAX NG XML syntax.

I don't see how the issue of how/whether to point to a portion of an xml
resource which happens to be in RNG, has *any* bearing on the issue of
what media type to use when RNG is served as a stand-alone document,
which is by far the typical case at the moment. There is no dependency
there.

MM> After all, it is ISO/IEC JTC1/SC34 that is requesting the
MM> registartion of a media type for the RELAX NG compact syntax. In its
MM> last meeting, SC34 decided to request this media type, but did not
MM> consider a specialized media type for the RELAX NG XML syntax.

So, now I am asking them to consider it. Will you convey this request to
them, or do I need to convey it by a more formal mechanism?

MM>  Since we are talking about
MM> media types in the standard tree, the media type for the RNG compact
MM> syntax can go to the IESG but that for the RNG XML syntax cannot.

I don't follow your last point there.

-- 
 Chris Lilley                    mailto:[email-masked]
 Chair, W3C SVG Working Group
 W3C Graphics Activity Lead

Date: Tue, 14 Jun 2005 23:47:40 +0900
From: MURATA Makoto <[email-masked]>
To: Mark Baker <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Mark> >And do you want to specify a 
Mark> > specialized media type when you reference the embedded RNG?
Mark> 
Mark> Ideally, yes, I think that would be valuable for the reasons I gave
Mark> before concerning layering and security.
Mark> 
Mark>  [1] http://www.w3.org/2004/CDF/
Mark>  [2] http://www.markbaker.ca/2004/01/XmlDispatchTest/

You propose to use a specialized media type for a fragment and 
to use a different media type for the entire resource.  It is a very 
interesting idea.  It might help the marriage between media types and 
multi-namespace XML documents.  But I do not think that MIME RFCs or
URI/IRI RFCs bless it (at least now).  Media types have been intended 
as values of the content-type field of MIME.  

You might want to raise this issue in the W3C CDF WG or W3C TAG, and 
you might even want to write an RFC that updates MIME RFCs or URI/IRI
RFCs.

However, unless such significant changes are endorsed, I continue 
to be very reluctant to register a specialized media type for 
the RELAX NG XML syntax.

After all, it is ISO/IEC JTC1/SC34 that is requesting the registartion
of a media type for the RELAX NG compact syntax.  In its last meeting, 
SC34 decided to request this media type, but did not consider a specialized 
media type for the RELAX NG XML syntax.  Since we are talking about 
media types in the standard tree, the media type for the RNG compact
syntax can go to the IESG but that for the RNG XML syntax cannot.

Cheers,

-- 
MURATA Makoto <[email-masked]>

Date: Mon, 13 Jun 2005 11:25:13 -0400
From: Mark Baker <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

Hey,

On Sat, Jun 11, 2005 at 03:50:03PM +0900, MURATA Makoto wrote:
> Mark> >Although 
> Mark> > your example can be addressed by specialized media types, my example 
> Mark> > (schemas embedded within XHTML are referenced by XPointer) cannot.
> Mark> 
> Mark> Can you elaborate on that example please?  I don't think I've seen any
> Mark> schemas embedded in XHTML before.
> 
> Consider the following XML document (say multi.xml).  This example is not 
> artficial.  It is useful for literate programming.  As you know better
> than me, W3C is trying to promote compound documents.

Right.  For those who weren't aware, the W3C has a Compound Document
Formats WG[1] that is trying to address some of these issues.  I'm on
the WG as a representative of Justsystem Corp.

> I would like to reference to the embedded RNG schema using multi.xml#rng. 
> What is the media type of this document?

You could use the text/html or application/xhtml+xml media types.  If
fallback rendering was a problem, you could add some styling directives,
or else just "display: None"-it and place an HTML description in there.
Fragment identifiers would work as expected.

You could use application/xml too, though as you know, you don't get
fragment identifers.  Also, IE doesn't make the same assumptions as
other browsers[2], and will only display the tree view.  Moreover, the
interpretation made by these other browsers isn't licensed by RFC 3023;

  An XML document labeled as text/xml or application/xml might contain
  namespace declarations, stylesheet-linking processing instructions
  (PIs), schema information, or other declarations that might be used
  to suggest how the document is to be processed.  For example, a
  document might have the XHTML namespace and a reference to a CSS
  stylesheet.  Such a document might be handled by applications that
  would use this information to dispatch the document for appropriate
  processing.

The CDF WG may or may not be defining a media type that is suitable for
what you need (I can't say until we publish), but I can say with
certainty that it isn't currently supported by any existing agent. 8-)

If it were me, I'd go with text/html if there was a reasonable
expectation that somebody with IE might want to plug a URI that returns
one of these documents into their location bar.  Otherwise I'd use
application/xhtml+xml.

>And do you want to specify a 
> specialized media type when you reference the embedded RNG?

Ideally, yes, I think that would be valuable for the reasons I gave
before concerning layering and security.

 [1] http://www.w3.org/2004/CDF/
 [2] http://www.markbaker.ca/2004/01/XmlDispatchTest/

Mark.
-- 
Mark Baker.  Ottawa, Ontario, CANADA.          http://www.markbaker.ca
Coactus; Web-inspired integration strategies   http://www.coactus.com

Date: Sat, 11 Jun 2005 15:50:03 +0900
From: MURATA Makoto <[email-masked]>
To: Mark Baker <[email-masked]>
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Mark,

Mark> >Although 
Mark> > your example can be addressed by specialized media types, my example 
Mark> > (schemas embedded within XHTML are referenced by XPointer) cannot.
Mark> 
Mark> Can you elaborate on that example please?  I don't think I've seen any
Mark> schemas embedded in XHTML before.

Consider the following XML document (say multi.xml).  This example is not 
artficial.  It is useful for literate programming.  As you know better
than me, W3C is trying to promote compound documents.

I would like to reference to the embedded RNG schema using multi.xml#rng. 
What is the media type of this document?  And do you want to specify a 
specialized media type when you reference the embedded RNG?

<?xml version="1.0" encoding="UTF-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
    <head xml:lang="en">
        <script type="JavaScript"/>
        <title dir="ltr" lang="en"/>
        <style type="das"/>
    </head>
    <body>
        <h1>Welcome to XHTML</h1>
        <div title="a RELAX NG grammar">
            <grammar 
                xml:id="rng"
                xmlns="http://relaxng.org/ns/structure/1.0"
                xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0"
                datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
                <start>
                    ...
                </start>
                ...
            </grammar>
        </div>
        <div title="a W3C XML Schema schema>
            <xs:schema 
                xml:id="wxs"
                xmlns:xs="http://www.w3.org/2001/XMLSchema">
                ...
            </xs:schema>
        </div>
    </body>
</html>

-- 
MURATA Makoto <[email-masked]>

Date: Fri, 10 Jun 2005 10:55:17 -0400
From: Mark Baker <[email-masked]>
To: MURATA Makoto <[email-masked]>
Cc: [email-masked]
Subject: Re: The role of media types for XML content
Sender: [email-masked]

Hey,

On Fri, Jun 10, 2005 at 08:04:28AM +0900, MURATA Makoto wrote:
> Mark,
> 
> (I do think that this topic belongs to the ietf-xml-mime ML.  I am 
> ccing to the ietf-types but will not do so any more.)

Sounds good.

For those on ietf-xml-mime and not on ietf-types, my original
message can be found here;

http://eikenes.alvestrand.no/pipermail/ietf-types/2005-June/000817.html

> I think that you have presented some requirements which are not
> addressed by any of the existing mechanisms. 
> 
> > But I believe the security problem is just one manifestation of the
> > layering problem inherrent in using intrinsic dispatch (of which XML
> > namespace dispatch in one kind); that an extrinsic dispatch mechanism,
> > like media types, cleanly separates the "what" - the raw data - from
> > the "how" - the semantics with which that data is to be interpreted.
> 
> I do not think that media types are good enough for multi-namespace 
> documents and that W3C should develop something different.

I think media types are fine for multi-namespace documents.  I just
think that XML, by itself, doesn't provide a sufficiently rich framework
to address the root cause of the need for an explosion of media types
with these documents.

Consider RDF/XML documents, almost all of which are comprised of data
from several independent namespaces.  Yet a single media type,
application/rdf+xml, suffices for (almost[1]) all RDF/XML documents.

>Although 
> your example can be addressed by specialized media types, my example 
> (schemas embedded within XHTML are referenced by XPointer) cannot.

Can you elaborate on that example please?  I don't think I've seen any
schemas embedded in XHTML before.

Cheers,

 [1] http://esw.w3.org/topic/RdfAndMediaTypes

Mark.
-- 
Mark Baker.  Ottawa, Ontario, CANADA.          http://www.markbaker.ca
Coactus; Web-inspired integration strategies   http://www.coactus.com

Date: Fri, 10 Jun 2005 08:04:28 +0900
From: MURATA Makoto <[email-masked]>
To: [email-masked]
Subject: Re: The role of media types for XML content
Cc: [email-masked]
Sender: [email-masked]

Mark,

(I do think that this topic belongs to the ietf-xml-mime ML.  I am 
ccing to the ietf-types but will not do so any more.)

I think that you have presented some requirements which are not
addressed by any of the existing mechanisms. 

> But I believe the security problem is just one manifestation of the
> layering problem inherrent in using intrinsic dispatch (of which XML
> namespace dispatch in one kind); that an extrinsic dispatch mechanism,
> like media types, cleanly separates the "what" - the raw data - from
> the "how" - the semantics with which that data is to be interpreted.

I do not think that media types are good enough for multi-namespace 
documents and that W3C should develop something different.  Although 
your example can be addressed by specialized media types, my example 
(schemas embedded within XHTML are referenced by XPointer) cannot.

Cheers,

-- 
MURATA Makoto <[email-masked]>