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Re: What the #@&*$(!@ is going on here?! (was RE: N-Triples for proposed xsi:type [was Re: xsi:type test case ]

From: pat hayes <phayes@ai.uwf.edu>
Date: Wed, 7 Aug 2002 12:08:45 -0400
Message-Id: <p05111b4eb976f5dc1cad@[65.217.30.57]>
To: Jan Grant <Jan.Grant@bristol.ac.uk>
Cc: w3c-rdfcore-wg@w3.org

>On Wed, 7 Aug 2002, Dave Beckett wrote:
>
>>
>>  >>>"Patrick.Stickler" said:
>>  > [lots]
>>
>>  Don't read into a proposed N-Triples syntax change more than I wrote.
>>  I could have put it has datatype(decimal, "2.0") or somesuch.
>>  Specifically don't read that as qnames but evocative of how XSD is
>>  used in XML; similar how the xsi:type is being used in this RDF/XML -
>>  a special attribute.
>>
>>  But I'm still waiting for the triples for these RDF/XML + xsi:type
>>  examples.  Which is hard to do if they have no n-triples syntax.
>>  I'll create a better N-triples if needed when I'm clear what (if
>>  anything) has changed in the graph.  Catch 22.
>
>What's changed in the graph is that the space of "literals" has
>expanded; that is that
>
>	jenny age "10" .
>
>and
>
>	jenny age number(10) .
>
>are distinct triples, but that
>
>	jenny age number(10) .
>	bob age number(10) .
>
>indicates that jenny and bob really do have the same age.
>
>As to how much it has expanded: this proposal seems to be capable of
>going two ways:
>
>1. the space of literals is expanded by a small set of other literal
>types to provide a sufficient foundation for datatyping to be built
>upon. That a small set can be sufficient is indicated by the success
>people have in using RDBM systems, I suppose. This proposal would then
>need guidelines as to what to do with other "datatypes": eg: factor out
>units in property values; use uri-labelled resources for enumerations
>and taxons; use graph-structure to express compound types.
>
>This reading means that the RDF parser must have a transform from some
>serialised form to the appropriate value, but that the values are what
>are present in the graph. In this case, the "hook" for that transorf is
>the xsi:type attribute. The space of literals is not extnsible by third
>parties.
>
>Presumably for datatyping and range constraints, etc, rdf:Literal
>(rdfs:Literal? I forget) is subclassed into numbers (or ints and reals),
>strings, langstrings, whatever.
>
>That literals are essentially self-denoting entities is obvious in this
>setup.

Well, no; in fact, they can't be self-denoting in this setup. If 
(int)10 is supposed to denote an integer, then if it were 
self-denoting it would have to be an integer, which it isn't. In 
fact, you can't put integers into syntax, so *anything* that denotes 
integers isn't self-denoting.

Pat


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Received on Wednesday, 7 August 2002 12:08:36 EDT

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