RE: [xml-dev] Identify PUBLICID outside of dtd?

["Chris Wilper" <cwilper@cs.cornell.edu>]

Hi Ken,

Thanks for your response and link... comments below

> The idea of allowing a public identifier alone was shot 
> down every time it was brought up.
> I don't think we'll ever see a public identifier allowed 
> alone ... we will always be required to supply a fallback 
> system identifier.  

There are now several languages to express (and to varying degrees)
the schema for a particular 'type' of document.  This is why
I'm thinking outside the DTD context, where the assumption
seems to have always been "there is one format for expressing
the schema to which this document conforms".

Just as the MIME "media type" identifiers (text/plain, image/gif)
identify the nature of a datastream without referencing a
particular expression of their format specification, I am
interested in the same kind of identifier for XML stream
natures.

I'm interested in doing this, not just for validation of
an XML document, but for datastream-to-agent binding.

I suppose I could make up a media type for my pet schemas and
submit it to IANA (appending it with the handy new +xml),
but in light of a TAG finding 
http://www.w3.org/2001/tag/2002/01-uriMediaType-9 essentially
saying "yes, existing media types should have URIs" and
it's blessing of RDDL as a possible way to describe
*namespaces* at the endpoints of URIs, *and* my belief that
an XML stream's "nature" is not unlike unlike a "Media type"'s
"nature"...  I'm thinking that having a URI to identify a 
doctype would ... be good...  Whether the format would be
registered with IANA or not is another issue.

- Chris

-----Original Message-----
From: G. Ken Holman [mailto:gkholman@CraneSoftwrights.com]
Sent: Tuesday, October 15, 2002 11:41 AM
To: xml-dev@lists.xml.org
Subject: Re: [xml-dev] Identify PUBLICID outside of dtd?


At 2002-10-15 10:51 -0400, Chris Wilper wrote:
>I am convinced that the concept of a DOCTYPE/PUBLICID
>identifying a doctype is needed...

Many people (myself include) already are convinced.

I think the last time this was discussed publicly was quite a while ago ... 
from my records the thread begins here:

   http://lists.xml.org/archives/xml-dev/199809/msg00427.html

I cannot find the original XML SIG discussions where this was hotly debated.

>Is anyone working on defining something like this?

The idea of allowing a public identifier alone was shot down every time it 
was brought up.

I don't think we'll ever see a public identifier allowed alone ... we will 
always be required to supply a fallback system identifier.  According to 
XML 1.0 4.2.2 a processor may choose to use the public identifier first and 
only if it fails need it use the fallback system identifier.  For this 
reason I don't think the issue of allowing it alone (which is what I think 
you are asking for) need be debated again ... just use a processor that 
respects the use of the public identifier (and whatever mechanism it 
chooses to use for resolution of the public identifier) and you don't need 
to change the definition of XML.

I hope this helps.

.................... Ken


--
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