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goofy literals

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Thu, 05 Jun 2003 13:47:34 +0100
Message-ID: <3EDF3BE6.4050906@hplb.hpl.hp.com>
To: RDF Core <w3c-rdfcore-wg@w3.org>

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."
 >>>>
Received on Thursday, 5 June 2003 08:47:56 EDT

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