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Re: adding {}s to grammar to address I18N-ISSUE-189

From: Sandro Hawke <sandro@w3.org>
Date: Sun, 07 Oct 2012 13:10:18 -0400
Message-ID: <5071B77A.2020001@w3.org>
To: public-rdf-wg@w3.org
On 10/07/2012 10:35 AM, Gavin Carothers wrote:
> On Sun, Oct 7, 2012 at 5:32 AM, Eric Prud'hommeaux <eric@w3.org> wrote:
>> The LC grammar includes a LANGTAG production
>>
>>    [144s] LANGTAG ::= '@' [a-zA-Z]+ ('-' [a-zA-Z0-9]+)*
>>
>> which doesn't match the one in BCP 47
>>
>>           obs-language-tag = primary-subtag *( "-" subtag )
>>           primary-subtag   = 1*8ALPHA
>>           subtag           = 1*8(ALPHA / DIGIT)
>>
>> (Basically, Turtle is too liberal in what it permits in a LANGTAG.)
>> The proposal from I18N was to reference
>>    http://tools.ietf.org/html/bcp47#section-2.1
>> which could mean one of:
>>
>> 1 remove the production rule and include instead (coursly) href the bcp47 defn.
>> 2 preserve our production and href the bcp47 rule informatively
>> 3 preserve our production and href the bcp47 rule normatively
>> 4 align our production and href the bcp47 rule normatively
>>
>> I've mocked up #4 in the editor's draft (my pref). See the last
>> sentence of
>> http://www.w3.org/2011/rdf-wg/wiki/I18n-Comments#189:_.5BS.5D_reference_obs-language-tag_instead_of_defining_your_own
>> for all the links.
> None of 1-4 provides an enhancement to the state of language tag
> parsing in Turtle. In order to use the grammar to test for a valid
> language tag it must be compared to the complete registration list,
> and be a legal composition. For even the lower bar of testing for a
> well formed language tag a much more complex grammar must be used. All
> of these solutions would simply add complexity without any real gain
> to anyone. RDF Concepts already requires, with a MUST no less,
> that "The language tag must be well-formed according to section
> 2.2.9", these additions to Turtle aren't enough to do that. Either we
> need to go all the way and specify the exhaustive grammar for well
> formedness or leave this alone and let something up stream of the
> parser confirm well formedness.

+1 but I wonder what the I18N-WG thinks of this argument. Presumably 
they've heard it before, and they might have an interesting response.

      - s

> --Gavin
>
>
>> --
>> -ericP
>>
>
Received on Sunday, 7 October 2012 17:10:26 GMT

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