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Re: specifying literals

From: Graham Klyne <GK@NineByNine.org>
Date: Sun, 15 Dec 2002 10:18:26 +0000
Message-Id: <5.1.0.14.2.20021215101436.03bb13a0@127.0.0.1>
To: Dan Connolly <connolly@w3.org>, Jeremy Carroll <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org

At 06:13 PM 12/13/02 -0600, Dan Connolly wrote:

>I see yet another specification of literals in
>http://lists.w3.org/Archives/Public/www-archive/2002Dec/att-0053/00-rc#section-Graph-Literal
>
>That has the same problem.
>
>Here's a suggested replacement:
>
>6.5 RDF Literals
>
>   To define a literal in an RDF graph,
>   let S be the set of Unicode
>   strings in Normal Form C,
>   L be the set of language identifiers [RFC3066],
>   and U be the set of RDF URI references.
>
>   A plain literal is an element of the
>   union of S with SxL; i.e. it's either
>   a string or a string paired with a
>   language identifier.
>
>   A typed literal is an element of the
>   union of SxU with SxUxL.
>
>   Note that U and L are disjoint
>   (every member of U contains a colon;
>    no member of L contains a colon),
>   so SxL doesn't intersect SxU.

Eh?  Where's this about literal strings not containing colons come from?

As far as I'm concerned, "a:b" is a perfectly good literal.

>Then literal equality falls out from
>the traditional definition of tuple
>equality and string equality.
>
>I don't see what the NOTE about literals
>being distinguisable from URI references
>is supposed to mean; that's the same sort
>of double-speak that's giving us trouble
>in the XML Schema spec.

It's meant to mean that:

   ex:subj ex:prop <http://example.org/abc> .

and

   ex:subj ex:prop "http://example.org/abc" .

are different graphs.

#g


-------------------
Graham Klyne
<GK@NineByNine.org>
Received on Sunday, 15 December 2002 05:55:43 EST

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