Re: 3023 update (was Re: Agenda TAG Telcon: 8th Nov 2004)

Tim Bray
>No.  In all cases of which I'm aware, data on the web that's served as 
>*/xml is a symptom of a bug, and it is not OK for agents, web robots or 
>any other kind, to infer #fragid rules.

Bjoern Hoehrmann 
> Further problems would arise in the context of compound documents,
> if FooML and BarML have different rules for what #foo refers to,
> implementation of it for a FooML+BarML document would probably be
> difficult (depending on the rules), worse if you have a XHTML+SVG+
> XForms+MathML+SMIL+sXBL+RDF document (which is not unlikely).

I strongly agree with this, current mechanisms for assigning mime types
really don't scale to compound documents. I don't think it's at all
clear what the answer is or should be and I'm happy to see W3C recently
started a CDF activity, which I hope will find an answer.

However despite Tim Bray's comments above that it's a symptom of a bug,
I think that for many document types (today at least) using
application/xml
has the best behaviour rather than continually inventing new mime types
which just result in an "unknown mime type" dialog and file/save option
on a typical client.

For example the XHTML + MathML version of the MathML spec,

http://www.w3.org/TR/mathml2/overview.xml

is actually served as text/xml. Well we've since learned that text/xml
should be deprecated and if doing it now it would be application/xml
although I don't think these documents actually suffer from being served
as text/* (as they only use ascii characters, and have entity or character
refs for anything else so are fairly immune to encoding isuses).

However there would be little point in serving the documents as
xhtml+xml or some newly invented type such as xhtml+mathml+xml as that
would simply stop the documents being rendered in a large percentage of
clients (i.e., IE).

That said, what the browsers actually do with #foo in the case of
arbitrary XML served as application/xml styled with XSL via the
xml-stylesheet pi is interpret the fragid in the (x)html that is
generated internally by the stylseet, not as an identifier in the XML
that is actually served. So even here (if one wanted to standardise
currently implemented behaviour) a pure XML xpointer based fragid syntax
wouldn't really help...

David

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Received on Monday, 22 November 2004 12:23:45 UTC