ietf-xml-mime
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Re: Inconsistency between IETF and W3C: XML fragments and media types

1999-11-24 19:47:11
Dan,

Thank you for your prompt action.  I am hoping that all relevant 
specs will be clear about the relationship between fragment identifiers 
and media types.

www-html-editor: I suggest that the definition of the "type"
attribute on the HTML "link" element needs clarification.

Yes, indeed.

MURATA Makoto wrote:

We are writing this mail as co-authors of Internet Draft which is
intended to replace RFC 2376.

Hmm... perhaps I've neglected some stuff that I should have read, but

There was an announcement of the IETF-XML-MIME ML in the XML CG on 
March 30.

        http://lists.w3.org/Archives/Member/w3c-xml-cg/1999Mar/0048.html

This announcement is linked from the XML Coordination Group 
(http://www.w3.org/XML/Group/) as the second item in the "Attention CG 
members:" 
section (at the very beginning).  Fortunately, Chris, Martin, and Bert 
have been involved in the discussion.  I have thought you are counting 
on them :-)

My recollection is that type="..." is advisory: it helps user agents
optimize for the case that they don't know the relevant media type,
so they can skip fetching the thing. 

The semantics of the type attribute in HTML and the 
stylesheet-linking PI has to be clarified.
 
Anyway... the type="text/xml" in the XSLT spec example is saying:
"the stylesheet I'm pointing to is written in XML; if you don't
grok XML, don't bother fetching it." Given that interpretation,
I don't think it really matters that the pointer includes a fragid,
regardless of the sort of "type mismatch error" in givin a MIME
type for an XPointer node.

We have to agree on some interpretation.  In your interpreation, if 
a CSS stylesheet having the text/css media type is referenced by a 
PI with type="text/xsl", those user agents which do not know XSL 
don't fetch the CSS stylesheet.  Is this OK?

This is a case where it might be useful to have a specific MIME
type for XSL(T), so that you could say:

      "the stylesheet I'm pointing to is written in XSL; if you don't
      grok XSL, don't bother fetching it."

When do we need specialized media types and when can we live with 
text/xml and application/xml?  There have been a lot of discussion 
in the IETF-XML-MIME ML.

Specialized media types often look convenient, but do you give 
up general-purpose XML processing such as XPointer and tree views 
(e.g., IE 5.0)?

Which media type should be used if an XML document contain XHTML and SVG, 
for example?  How do we interpret fragment identifiers for such documents? 
(People would like to reference to an SVG element by an XPointer and 
then address an SVG element via a SVG view specification [1].)

[1] http://www.w3.org/TR/SVG/linking.html#LinksIntoSVG

We have agreed that specialized media types on XML will appear anyway.  
xml/*, */xml/*, */xml-*, */*;xml=1.0 have been proposed, but have 
not been agreed.

I see no consensus about interpretation of fragment identifiers. ;-(

Cheers,

Makoto
 
Fuji Xerox Information Systems
 
Tel: +81-44-812-7230   Fax: +81-44-812-7231
E-mail: murata(_dot_)makoto(_at_)fujixerox(_dot_)co(_dot_)jp