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Re: XML observation

From: Graham Klyne <gk@ninebynine.org>
Date: Wed, 09 Jul 2003 09:19:12 +0100
Message-Id: <>
To: Martin Duerst <duerst@w3.org>, pat hayes <phayes@ihmc.us>, w3c-rdfcore-wg@w3.org
Cc: w3c-i18n-ig@w3.org

At 17:21 08/07/03 -0400, Martin Duerst wrote:
>>Hmmm... I'm not sure what the implication of this may be.
>>RDF/XML syntax is (now) defined in terms of the XML infoset
>>of the containing XML document.  So, I think, that suggests that
>>XML literals in RDF/XML must likewise be defined.  Or maybe not,
>>because RDF literals are defined (in some cases partly) in terms
>>of the Unicode string that represents the literal.
>>At best, it feels rather convoluted.
>Sorry for my imprecision. I think I should have said that
>Tim wasn't aware of the fact that there was no need to use
>the Infoset in an RDF store. An RDF parser will of course
>use the infoset in whatever way it is exposed by the API
>of the underlying XML parser when it parses RDF/XML.

Er, maybe I'm being plain dumb here, but I still struggle to grasp the 
implication.   In a sense, it's "obvious" that an infoset processor is not 
*needed*, since infoset is an abstract data model, and implementers can do 
their own thing.  On the other hand, RDF/XML being defined in terms of 
infoset does somewhat confine its behaviour to be in terms of the infoset.

My current take is that the XML literal has an lexical form (in the RDF 
abstract syntax) that is the EXC-C14N representation of the infoset 
elements corresponding to the content of a parseType-Literal element.  That 
is what I meant by convoluted.  But maybe that's just how it must be.

>>>And the inclusion of XML literals in RDF is not a mistake, it's
>>>important for i18n reasons. I feel it's terribly sad that this
>>>gets ignored here time and again.
>>You don't quite say this, but this suggests the purpose of XML
>>literals in RDF is for I18N.  If so, this would be the first time
>>I've heard that suggested.
>It is true that I18N was a major advocate for including them
>in RDF in the first place. That does not mean that XML literals
>in RDF are for I18N only, of course. But it hopefully makes it
>understandable that changes to the original design (such as
>throwing out xml:lang from XML literals, disconnecting plain
>literals and XML literals,...) are seen in a very bad light
>on our side.

I think this is useful data.

>>This is very suggestive of the role of XML as text-with-markup,
>Yes indeed. As I said already, that's what XML literals
>were designed for, because there was no other standard way
>to include text-with-markup into RDF, and because text-with-markup
>was considered too important a thing (expecially for i18n) to
>just drop.

OK, I can appreciate that desideratum.

>>to my mind does little to square that role with XML-for-arbitrary-data.
>Yes, it doesn't. And for RDF, it doesn't have to. If you have
>structured data, and you want to handle it in RDF, you should
>use RDF, not XML. I'm surprised that I should have to tell you.

(You don't have to tell me -- I've always favoured such an approach.  But 
at this point I'm trying to understand where the *requirements* are coming 
from, and for that purpose am trying to suspend some of my own technical 

>>I find this lack of clarity about the role of XML to be really unsettling,
>>because, as Pat has pointed out, there are some real tensions here.
>The tension is here. But RDF has the chance to absorb this
>tension in an elegant way, rather than to increase it.

That would be good ;-)

I shall think some more about what you say, and maybe respond separately.

>>(Hmmm... general W3C process point:
>>given I18N is regarded as so fundamental, I think the purpose would be
>>better served by having I18N *participation* from the beginning, or
>>at the beginning, not occasional reviews later in the process.)
>As Misha already pointed out, I18N was involved from early on
>in the M&S days. Misha was a full participant in the RDF WG.
>Also, there was a joint meeting at the Technical Plenary in
>Cannes in Feb or March 2002.

As I responded to Misha, somehow the I18N role of XML literals somehow 
didn't come over clearly, at least to me.  (This is not intended as a 
criticism of any persons concerned, but as feedback which may or may not 
help you to achieve your worthy goals more effectively in future.)


Graham Klyne
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
Received on Wednesday, 9 July 2003 04:53:10 UTC

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