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Re: goofy literals

From: Frank Manola <fmanola@mitre.org>
Date: Thu, 05 Jun 2003 09:04:44 -0400
Message-ID: <3EDF3FEC.55C28813@mitre.org>
To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
CC: RDF Core <w3c-rdfcore-wg@w3.org>

Could you please suggest what, if anything, should be done to the Primer
if this proposal is accepted?

Jeremy Carroll wrote:
> 
> Issuette:
> Should we change the term: "plain literal" to mean a literal of just a
> lexical form, and then have a new term "language tagged literal"?
> 
> Possible text based on a 'yes' to this question is:
> 
> Section 6.5 RDF Literals
> 
> [[
> A literal in an RDF graph contains one or two named components.
> 
> All literals have a lexical form being a Unicode [UNICODE] string in Normal
> Form C [NFC].
> 
> Language tagged literals have a lexical form and a language tag as defined
> by [RFC-3066], normalized to lowercase.
> 
> Typed literals have a lexical form and a datatype URI being an RDF URI
> reference.
> 
> Plain literals do not have a language tag or datatype URI.
> ]]
> Notes etc unchanged.
> 
> Possible text based on a 'no' answer (i.e. the term 'plain literal' is
> unchanged)
> 
> Section 6.5 RDF Literals
> 
> [[
> A literal in an RDF graph contains one or two named components.
> 
> All literals have a lexical form being a Unicode [UNICODE] string in Normal
> Form C [NFC].
> 
> Plain literals have a lexical form and optionally a language tag as defined
> by [RFC-3066], normalized to lowercase.
> 
> Typed literals have a lexical form and a datatype URI being an RDF URI
> reference.
> 
> ]]
> 
> (Hmmm I had thought that the 'yes' text was going to be obviously better,
> but it's not clear).
> 
> The rest of the goofy literals proposal is more-or-less as in:
> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003May/0151.html
> with possible knock on effects of the terminology change with plain
> literals. (Note some of these knock on effects occur in semantics and are
> quoted in the issue resolution below. The equivalent text in 2003May/0151
> is with the meaning of plain literal unchanged).
> 
> Further note: the wording used, which actually caused the comment, is
> intended to be suggestive of a many sorted logic to prevent confusion
> between say a language tagged literal and a typed literal, or a plain
> literal and a uriref. I avoid being explicit about this because: (a) I
> think it is overkill solving a problem that isn't really there - this is
> obvious (b) the complexity of explaining a many sorted logic is greater
> than the benefit in clarity (c) I believe the wording in semantics allows
> the separation of the domain of discourse questions from the abstract
> syntax questions.
> 
> <<
> PROPOSE
> Accept danc-02.
> Our design of literals was a bit goofy, and we have changed it:
> [[
> **new text as above**
> ]]
> Moreover, we believe some of the concern was to do with the denotation of
> literals in the domain of discourse. To avoid copying any goofiness in the
> abstract syntax into the domain of discourse,
> we have hence changed the following rule in rdf-mt:
> http://www.w3.org/TR/2003/WD-rdf-mt-20030123/#gddenot
> From
> "if E is a plain literal then I(E) = E"
> to
> http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/#gddenot
> "if E is a plain literal "aaa" then I(E) = aaa"
> "if E is a language tagged literal "aaa"@ttt then I(E) = <aaa, ttt>"
> 
> The textual gloss is:
> "Plain literals and language tagged literals are always interpreted as
> referring to themselves: a character string or a pair consisting of
> two character strings."
> 
> The informative text in concepts:
> "As recommended in the RDF formal semantics [RDF-SEMANTICS], these plain
> literals are self-denoting."
> becomes
> "As recommended in the RDF formal semantics [RDF-SEMANTICS] plain
> literals and language tagged literals are self-denoting."
>  >>>>

-- 
Frank Manola                   The MITRE Corporation
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mailto:fmanola@mitre.org       voice: 781-271-8147   FAX: 781-271-875
Received on Thursday, 5 June 2003 09:04:55 EDT

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