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Re: SPARQL: language tag issues

From: Dan Connolly <connolly@w3.org>
Date: Mon, 21 Nov 2005 19:27:55 -0600
To: Bjoern Hoehrmann <derhoermi@gmx.net>
Cc: Eric Prud'hommeaux <eric@w3.org>, public-rdf-dawg-comments@w3.org
Message-Id: <1132622875.26034.113.camel@dirk>

On Fri, 2005-11-11 at 12:19 +0100, Bjoern Hoehrmann wrote:
> * Eric Prud'hommeaux wrote:
> >  Returns true if language-range (first argument) matches language-tag
> >  (second argument) per Tags for the Identification of Languages
> >  [RFC3066] section 2.5. RFC3066 defines a case-insensitive,
> >  hierarchical matching algorithm which operates on ISO-defined
> >  subtags for language and country codes, and user defined subtags. In
> >  SPARQL, a language-range of "*" matches any non-empty language-tag
> >  string.
> 
> http://lists.w3.org/Archives/Public/spec-prod/2005OctDec/0007.html would
> suggest to change the reference to the more generic BCP 0047, XML 1.0
> uses "The values of the attribute are language identifiers as defined by
> [IETF RFC 3066], Tags for the Identification of Languages, or its
> successor" -- either is fine with me as long as it is clear that SPARQL
> does not need to be revised in order to consider the successor of RFC
> 3066 as the normative reference. The links also lack ".txt" which is
> included for other RFC references.
> 
> Do I understand correctly that for some RDF with xml:lang="" or no in-
> scope language information "*" would not match?

Good question... that's how I read "non-empty language-tag string" too.

Eric, let's be sure there's a test case or three for this to be sure
we know what the answer is.

>  That would be different
> from e.g. how the Accept-Language:* header would be interpreted, is
> there a specific reason for this difference?

One possible reason is that xml:lang="" doesn't produce a literal
whose lang is the empty string; it produces a literal with no lang.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Tuesday, 22 November 2005 01:28:05 GMT

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