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Re: Parser mods to support rdf:dtype and rdf:lform

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Fri, 15 Feb 2002 13:16:20 +0200
To: ext Brian McBride <bwm@hplb.hpl.hp.com>, RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <B892BAA4.EA21%patrick.stickler@nokia.com>
On 2002-02-15 12:10, "ext Brian McBride" <bwm@hplb.hpl.hp.com> wrote:

> At 11:04 15/02/2002 +0200, Patrick Stickler wrote:
> [...]
>>    <dc:date rdf:value="2002-02-14" rdf:dtype="&xsd;date"/>
> Am I right that under the current proposal this can be more compactly written:
>  <dc:date xsd:date="2002-02-14"/>

Yes and no. It is more compact, but is less local (thus it
is not exactly an equivalent variant of the doublet idiom).

In this case, it is not clear from the RDF that xsd:date is a
datatype. It could be any kind of property at all. It has
no more datatyping clarity to the parser than

   <dc:date foo:bar="2002-02-14"/>

And it is unclear, if e.g xml:lang is specified, whether
the value of xsd:date or foo:bar is the actual literal
value of the dc:date property or just some extra attribution
of the bNode. Thus, schema knowledge would be required
by the parser (not just pre-defined automatic statements
in the spec) to know for sure that xsd:date or foo:bar
should be treated as rdf:value.

And one would not, I think, expect xml:lang to apply to
all attributes of the element -- or really to any of
the attributes, but rather only the content of the element,
and it's just a trick of rdf:value that the content can
be hidden (contracted) into an attribute.

If I have

 <dc:title rdf:value="Foo" xml:lang="en" x:scope="237a87"/>

we're saying that "Foo" is English, but not "237a87".

Yet if I have

 <dc:title xsd:string="Foo" xml:lang="en" x:scope="237a87"/>

how does the parser know which attribute, if any, denotes
the actual content of the dc:title property element?

Thus, with the datatype triple idiom, the parser cannot
know what is or is not the content of the property element
to which xml:lang is to be attached simply from the
vocabulary used in the idiom itself.

I admit that it's a handy form of expression, but these
issues have to be resolved before we're completely
done, I think.

> which would require no change to the parsers?

Correct, in that the required bNode is generated.
Apologies for missing this in my earlier examples.

Though, as pointed out above, proper attachment of xml:lang
to the literal either requires schema knowledge or results
in over-attachment to all attributes.


Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Friday, 15 February 2002 07:27:13 UTC

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