Re: Comments on SPARQL Query Language for RDF (draft)

Seaborne, Andy wrote:
> Arjohn Kampman wrote:
>> - <LANGTAG> only allows language tags that consists of max two
>>    components. However, the following document also seems to use tags
>>    with three or more tags like "zh-min-nan" and "en-GB-oed":
>>    http://www.iana.org/assignments/language-tags
> 
> 
> I believe the grammar is already aligned with RFC 3066.  The token A2Z 
> is not a
> 2 characters; it's "A to Z".
> 
> <LANGTAG>   ::=  '@' <A2Z>+ ('-' (<A2ZN>)+)?
> 
> and RDF 3006 has:
> 
> Language-Tag = Primary-subtag *( "-" Subtag )
> Primary-subtag = 1*8ALPHA
> Subtag = 1*8(ALPHA / DIGIT)
> 
> (I also note that the language-tags document has tags that are not 
> covered by the production in 3066).

Please note that these two production rules are not equivalent: the
former allows 0 or 1 subtags but the latter allows 0 or more. The '*'
character before the subtag part denotes this (don't you just love these
alternative bnf notations...;-)). This should be fixed by replacing the
'?' character with a '*' in the former rule, i.e.:

replace:
   <LANGTAG>   ::=  '@' <A2Z>+ ('-' (<A2ZN>)+)?
with
   <LANGTAG>   ::=  '@' <A2Z>+ ('-' (<A2ZN>)+)*


--
Arjohn