W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

Re: datatypes and MT

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Thu, 8 Nov 2001 20:24:25 -0600
Message-Id: <p05101022b810eb270e90@[65.212.118.147]>
To: Dan Connolly <connolly@w3.org>
Cc: w3c-rdfcore-wg@w3.org
>Pat Hayes wrote:
>
>>>  > I think we need to nail down the handling of simpler cases before getting
>>>
>>>>  too involved in arcane syntax options.  By simpler cases, I mean 
>>>>how are we
>>>>  to interpret simple RDF like this:
>>>>
>>>>     <rdf:Description rdf:about="#me">
>>>>       <ex:shoeSize>10</ex:shoeSize>
>>>>     </rdf:Description>
>>>
>>>
>>>dirt simple:
>>>
>>>     <...#me> <...#shoeSize> "10".
>>
>>
>>No no, wait a minute. You are having your cake and eating it. That 
>>triple doesn't conform to your proposed idiom;
>
>
>
>Indeed, that triple doesn't conform to my proposed idiom, but
>that's because the RDF from which it's transcribed doesn't conform.
>I don't want folks to write that sort of RDF.

Yes, but what if they do write it? Its not *illegal*.

Oh, I think I see, For you, all literals are strings, right? No 
exceptions. So if I say my shoesize is a string, then that's what I'm 
saying; and if that's not what I meant, then silly me.

But now consider the following circumstance. Suppose that for some 
weird reason, something knows that Pat's shoeSize is represented by a 
literal string "10", and that's all it knows. Maybe a page scraper 
found it somewhere and wants to record what it found in RDF. However, 
it has no idea how this string is supposed to be interpreted; it 
hasn't had time yet to look up 'shoeSize' to find out what datatype 
it expects to be using. It will do that later, maybe. What can it do? 
It shouldn't write

Pat shoeSize "10" .

on your scheme, since that is only correct if shoeSize uses a string. 
What it ought to is write something like this:

Pat shoeSize _:1 .
_:1 <some unknown datatype> "10" .

But there is no way to write that if you don't know the datatype.

(Hmmm. Maybe this is a case use for anonymous predicates. If we could write

Pat shoeSize _:1 .
_:1 _:2 "10" .
_:2 rdf:type rdfs:Datatype .

that might be just right.)

Maybe what it ought to write is something like

Pat temp:ShoeSize "10" .

temp:ShoeSize temp:tobereplacedby shoeSize .

and then leave the re-transcription to something else which knows 
about temp: names (??)

Pat
-- 
---------------------------------------------------------------------
IHMC					(850)434 8903   home
40 South Alcaniz St.			(850)202 4416   office
Pensacola,  FL 32501			(850)202 4440   fax
phayes@ai.uwf.edu 
http://www.coginst.uwf.edu/~phayes
Received on Thursday, 8 November 2001 21:24:20 EST

This archive was generated by hypermail pre-2.1.9 : Wednesday, 3 September 2003 09:42:35 EDT