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Re: rdf:text draft

From: Pat Hayes <phayes@ihmc.us>
Date: Tue, 26 May 2009 18:05:56 -0500
Message-Id: <E36E84B2-4BF3-4AFB-B461-1B89418BBAF8@ihmc.us>
To: public-rdf-text@w3.org
> On May 26, 2009, at 3:43 PM, Sandro Hawke wrote:
>> Nice explanation.  Can you send the RDF' bit, or what you like, to  
>> the
>> mailing list?

Which I did, which is why y'all are reading this.  "RDF' " is the  
'plain typed RDF' in that draft I just posted a link to.

>>  Thanks!
>>     - s
>>> On May 25, 2009, at 12:02 AM, Sandro Hawke wrote:
>>>>> Let me try to explain.
>>>>> I see where Boris is going, but just saying that the literal  
>>>>> must not
>>>>> be used doesn't work. The point is, who has the authority to say  
>>>>> that
>>>>> a certain datatyped literal MUST NOT be used? After all, RDF  
>>>>> itself
>>>>> does not prohibit any legal datatype to be used to type a literal,
>>>>> and
>>>>> there is nothjng in the idea of a datatype itself that allows a
>>>>> datatype to exert any kind of prohibition over RDF syntax. The RDF
>>>>> datatype description certainly does not give any provision for a
>>>>> datatype to exert any restrictions on RDF syntax. So if someone  
>>>>> were
>>>>> to publish some RDF with literals of the form "foo"^^rdf:text,  
>>>>> they
>>>>> would not be doing anything illegal according to the RDF specs.  
>>>>> That,
>>>>> it seems to me, is the core issue here: a datatype definition,
>>>>> speaking precisely, can only define a datatype. It cannot say that
>>>>> certain RDF syntactic forms MUST NOT be used. It simply is not the
>>>>> kind of spec that can have this kind of authority: that just isn't
>>>>> the
>>>>> kind of thing that datatypes do. So the second paragraph says  
>>>>> "this
>>>>> specification semantically extends RDF by introducing a datatype
>>>>> called rdf:text."  but that cannot be right, since just defining a
>>>>> datatype cannot itself extend or alter RDF.
>>>> It seems to me that any time people have a reasonable choice about
>>>> what
>>>> to do with their computers, and it would been good for the world  
>>>> for
>>>> people to act in concert, then it's appropriate for W3C to issue a
>>>> Recommendation telling them what to do there.  If it were actually
>>>> thought to be good for everyone, I think W3C could perfectly well
>>>> issue
>>>> a Recommendation to never use URL's in RDF which ended in the  
>>>> letter
>>>> "q".
>>> Hmm, I guess we think differently. The W3C does not lay down laws:  
>>> it
>>> makes recommendations which define various notations and formats
>>> (HTTP, HTML, RDF, etc. etc.)  For instance, the W3C has issued the  
>>> OWL
>>> recommendation, but if Im not claiming to process OWL, I can just
>>> ignore it. I'm only obliged to follow it if I'm claiming to be
>>> conforming to that particular Recommendation's specs.  Right now,  
>>> the
>>> use of rdf:PlainLiteral typed literals is legal RDF, according to  
>>> the
>>> RDF specs. I don't see how anything that anyone can say can change
>>> that: its just a fact we have to live with. If someone want to say
>>> that they are following the RDF spec, and ignoring other W3C specs,
>>> then they are perfectly justified in using it, even if some other
>>> document says if SHOULD/MUST not be used. They aren't claiming to
>>> conform to that other document's views.
>>> Seems to me that this is at the heart of the problem here.  
>>> Defining a
>>> datatype is one thing, and imposing a new syntactic condition on RDF
>>> syntax is something else. Mashing them is just going to create
>>> confusion. (Did I say "going to'?) So, I suggest, we don't try to
>>> retrospectively impose things on RDF: we (in effect) define a new
>>> RDF' (though that is a VERY small prime, there) on which we do  
>>> impose
>>> our own conditions, and strongly suggest that people use RDF'  
>>> instead.
>>> We point out that unless you are undertaking to utilize this new
>>> datatype, then RDF' is indistinguishable from RDF; and even if you
>>> are, its still a subset of RDF which can express everything that RDF
>>> can in exactly the same way that RDF always has expressed it, so  
>>> using
>>> RDF' is zero cost and can be achieved simply by saying publicly that
>>> you are doing it. What it amounts to in practice is, in effect,
>>> announcing that you are NOT going to use this new datatype. And  
>>> then,
>>> of course, not actually using it.
Received on Tuesday, 26 May 2009 23:06:35 UTC

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