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Re: Datatype proposal G (oh no!)

From: Sergey Melnik <melnik@db.stanford.edu>
Date: Tue, 04 Dec 2001 14:28:29 -0800
Message-ID: <3C0D4E0D.A77CBD23@db.stanford.edu>
To: Graham Klyne <GK@NineByNine.org>
CC: RDF core WG <w3c-rdfcore-wg@w3.org>
Oops, Graham, I read your posting after writing
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Dec/0004.html.
There, Idiom B corresponds pretty much to what you suggested. And I
agree that this alternative idiom could be used as a convenient
migration path.

Sergey


Graham Klyne wrote:
> 
> This isn't really a new proposal, so much as some extra definitions that I
> see as allowing proposal S to work with some naive usage of RDF.  It is my
> attempt to pull together comments from other messages into a single place
> for consideration.
> 
> My understanding is that at the heart of proposal S is the idea that RDF
> literals denote strings.  What I want to propose here is an account of how
> XML schema datatypes can be used with RDF, scheme S handling of literals,
> and the original model theory from F2F.
> 
> (I'm basing much of my understanding of S on Sergey's message at
> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Nov/0312.html and
> sliding around the datatype-as-property aspect.)
> 
> Let 'foo' be an XML schema datatype (e.g. 'integer').  The URI derived from
> the XML schema specification for this would be:
>      http://www.w3.org/2001/XMLSchema#foo
> or
>      http://www.w3.org/2001/XMLSchema-datatypes#foo
> 
> XML schema talks about a datatype having a value space and a lexical space
> (http://www.w3.org/TR/xmlschema-2/#datatype).
> 
> My proposal is that additional datatype-related URIs be defined, based on
> the XML schema space, such as:
>      http://www.w3.org/2001/XMLSchema-datatypes#foo
>      http://www.w3.org/2001/XMLSchema-values#foo
>      http://www.w3.org/2001/XMLSchema-mappings#foo
> where:
> http://www.w3.org/2001/XMLSchema-datatypes#foo denotes the lexical space of
> the datatype.
> http://www.w3.org/2001/XMLSchema-values#foo denotes the value space of the
> datatype.
> http://www.w3.org/2001/XMLSchema-mappings#foo denotes an RDF property that
> relates the value space to its lexical space
> 
> Thus, in N3, we might have:
> 
>      @prefix xsd-lex: <http://www.w3.org/2001/XMLSchema-datatypes#> .
>      @prefix xsd-val: <http://www.w3.org/2001/XMLSchema-values#> .
>      @prefix xsd-map: <http://www.w3.org/2001/XMLSchema-mappings#> .
>      @prefix ex: <http://example.org/> .
> 
>      xsd-lex:integer a rdfs:Class .
>      xsd-val:integer a rdfs:Class .
>      xsd-map:integer a rdf:property .
>      xsd-map:integer rdfs:domain xsd-val:integer .
>      xsd-map:integer rdfs:range  xsd-lex:integer .
> 
>      _:number0 rdf:type xsd-val:integer .
>      _:number0 rdf:xsd-map "0" .
>      _:number1 rdf:type xsd-val:integer .
>      _:number1 rdf:xsd-map "1" .
>       :
>      (etc.)
> 
>      ex:person ex:age_in_years_as_string "10" .
>      ex:age rdfs:range xsd-lex:integer .
> 
>      ex:person ex:age_in_years
>         [ a xsd-val:integer ; xsd-map:integer "10" ] .
> 
> ..
> 
> What all this means is that there's nothing new to define for RDF.  The
> idiom for dealing in detail with values and their lexical representation is
> pretty much as indicated by S.  But the naive approach of using strings
> directly is also supported, with a clear migration path (i.e. use new
> properties) from the naive approach to the more precise form that is the
> preferred idiom.
> 
> #g
> 
> -------------------------
>        __
>       /\ \    Graham Klyne
>      /  \ \   (GK@ACM.ORG)
>     / /\ \ \
>    / / /\ \ \
>   / / /__\_\ \
> / / /________\
> \/___________/
Received on Tuesday, 4 December 2001 17:00:30 EST

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