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Re: language-tagged literal datatypes

From: Richard Cyganiak <richard@cyganiak.de>
Date: Mon, 22 Aug 2011 18:55:54 +0100
Cc: Pat Hayes <phayes@ihmc.us>, "public-rdf-wg@w3.org Group WG" <public-rdf-wg@w3.org>
Message-Id: <69C95D8C-7DE6-469A-88CE-86F991C05877@cyganiak.de>
To: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
On 22 Aug 2011, at 17:59, Pierre-Antoine Champin wrote:
>> Terminology question. What's the “lexical form” of a language-tagged string?
>> 
>> a) it's a pair of string and language tag
>> b) it's just the string; the language tag is not considered part of the lexical form
>> c) it doesn't have one, only typed literals have a lexical form
>> 
>> My preference would be b), because it seems nicely consistent with the use of the term for typed literals.
> 
> well, the notion of "lexical form" only makes sense in the context of a
> datatype, and in relation with a "value".

Why are you saying that? In RDF 2004, plain literals have a lexical form, despite not having a datatype [1].

And a typed literal still has a lexical form even if its datatype IRI doesn't actually name a datatype.

> In your proposal,
> rdf:LangString is not a real datatype, and there is no L2V mapping, so
> at this stage, speaking of the "lexical form" of the language-tagged
> string seems pointless to me...
> 
> I'd rather swallow it all and consider that there is no lexical form,

That would be yet another terminology change from RDF 2004, and I don't see the benefit of that change.

Quoting from [1]:

[[
Plain literals have a lexical form and optionally a language tag […].
]]

This reinforces my preference for b) above. The lexical form of "foo"@en in RDF 1.1 should still be the same as the lexical form of "foo"@en in RDF 2004.

> (which, in a sense, is already the case for xsd:string as L2V is the
> identity mapping).

Not really. Lexical form and value are identical. That doesn't mean it has no lexical form.

> Note that, if you really want language-tagged strings to have a lexical
> value (that does not embed the language tag), you might be interested in
> my proposal 3a from another sub-thread...

I don't much like 3 nor 3a. There's lots of mechanics there that just complicate the spec and don't actually *do* anything except mapping A to A, and still it misses the original goal of making DATATYPE("foo"@en) in SPARQL a datatype. Your 2c proposal is simpler and better.

Best,
Richard

[1] http://www.w3.org/TR/rdf-concepts/#section-Graph-Literal
> 
>  pa
> 
>> 
>> Best,
>> Richard
> 
> 
Received on Monday, 22 August 2011 18:12:51 GMT

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