W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > December 2002

Re: handling rdf:value

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 9 Dec 2002 18:09:19 -0600
Message-Id: <p05111b21ba1aca0378ab@[10.0.100.86]>
To: Graham Klyne <GK@NineByNine.org>
Cc: w3c-rdfcore-wg@w3.org

>At 10:36 AM 12/9/02 -0600, pat hayes wrote:
>>Well, yes, but rdf:value *is* contextual, but at least this keeps 
>>it in bounds. I'd prefer to abandon it, but that's apparently not 
>>an option.
>
>Er, yes.  In the past few days, I've come across a few instances of 
>its use in RDF schedule data.  Some of which, I think, doesn't 
>conform with your proposed "abbreviated form" approach;  e.g.

Well, if I understand these examples, it seems to me that they do, at 
least plausibly. I gather that the value of the rdf:value triples 
here is a representation of the 'full' value, and that the others are 
'pieces' of it broken out for access via RDF reasoning, is that 
correct? Because if so, that fits perfectly: in this case presumably 
it would, or at least could, be appropriate to write that 'full' 
value as the value of the DTSTART property of the event, no?

>
>[[
><VEVENT>
><!--- snipped -->
><DTSTART>
>
><DATE-TIME>
><TZID rdf:resource="#US-Eastern"/>
><rdf:value>20010226T090000</rdf:value>
><util:hour>09</util:hour>
><util:minute>00</util:minute>
></DATE-TIME>
></DTSTART>
>
><DTEND>
><DATE-TIME>
><TZID rdf:resource="#US-Eastern"/>
><rdf:value>20010227T173000</rdf:value>
><util:hour>17</util:hour>
><util:minute>30</util:minute>
></DATE-TIME>
></DTEND>
></VEVENT>
>]]
>-- http://www.ilrt.bristol.ac.uk/discovery/2001/06/content/rdf_meeting.rdf
>
>This is just an example picked at random.  I've noticed this pattern 
>a couple of times in iCalendar/RDF data.

Look, there is a more general issue here. Our charter asks us to make 
the RDF M&S clear. That thing that we were supposed to clarify has 
spawned this monstrosity BY BEING UNCLEAR about what rdf:value is 
supposed to mean or to be appropriately used for. The result, that 
existing code use it for all kinds of not-mutually-compatible things, 
is the PROBLEM that we are supposed to be solving, seems to me, not 
the state of affairs that we are supposed to preserve by avoiding 
anything that might violate some use case. If the existing use cases, 
taken as a whole, are confused, then one or more of them have GOT to 
change, or else we just declare that confusion reigns and we are not 
going to do anything about it. Which, to return to my first point, 
seems to me to be a clear violation of our charter. If confusion were 
supposed to reign, there would have been no need to form this WG in 
the first place.

So I think that we should say something that makes an intended use 
case for rdf:value reasonably clear, and then say that this is what 
rdf:value is supposed to mean. We should try to capture as many use 
cases as we can, of course, but if we can't get them all, we should 
not just give up. Im not sure what the above pattern is supposed to 
mean, to tell you the truth, but if it can't be interpreted in the 
way I suggest, then iCalendar/RDF will have to invent a new property: 
tough.

Pat

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Received on Monday, 9 December 2002 19:09:49 EST

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