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Re: qname shortland starting with a digit

From: Andy Seaborne <andy.seaborne@hp.com>
Date: Mon, 29 Jun 2009 18:18:47 +0100
Message-ID: <4A48F777.8040007@hp.com>
To: Tim rdf <timrdf@gmail.com>
CC: luc peuvrier at home <lc.pvrr@orange.fr>, ++cwm talk <public-cwm-talk@w3.org>


Tim rdf wrote:
> Luc,
> 
> Sesame 2.2.4 does not handle digits at the start of the local part of a QName, either. (Perhaps 3.0b does, but I haven't found the time)
> 
> Jena 2.5.4 and Jena 2.6.0 do, however.
> 
> Rather annoying behavior. I heard claims of "Historic XML namespace QName compliance", but Saxon handles elements with "digit names" in Plain Old XML....
> 
> Does anyone know why tools are mixed on how they handled digits in QNames? I would imagine that it would be a natural desire.


The Jena reader is adhering to the principle of being permissive in what 
it accepts.  The Jena readers for Turtle are derived from SPARQL where 
the local part of a prefixed name does allow a digit as the start char.

QNames (as in the XML Namespaces concept) do not allow the local part to 
start with digit.  SPARQL does not call it's abbreviations "qnames".

Turtle submission:
"""
10. Turtle compared to SPARQL
...
# SPARQL allows '.'s in names in all positions apart from the first or last.
# SPARQL allows digits in the first character of the PN_LOCAL lexical 
token. In Turtle, the only ascii characters allowed in a nameStartChar 
are [A-Z] | "_" | [a-z].
"""

SPARQL changed to allow the leading digits in the local part during the 
time of the original working group based on quite a lot of user input.

I don't know of any reason not to accept digits at the start of the 
local part.  For URIs derived from other naming schemes, it comes up 
naturally and forcing full forms <>, or strange prefix choices, adds no 
value.

	Andy



> 
> Regards,
> Tim Lebo
> 
> On Mon, Apr 27, 2009 at 5:49 AM, luc peuvrier at home <lc.pvrr@orange.fr<mailto:lc.pvrr@orange.fr>> wrote:
> Hi,
> 
> For the following uri <http://tap.xmlns.com/data/7UpBrand>
> 
> A n3 file can contains:
> 
>   @prefix data: <http://tap.xmlns.com/data/>
>   :x a data:7UpBrand
> 
> The n3 grammar do not accept "data:7UpBrand"
> 
> I propose to change qname non terminal definition as follow:
> 
> [qname] : name       | ':' n_name_opt
>       | name ':' n_name_opt
>       ;
> 
> n_name_opt :
>          | n_name
>          ;
> 
> where n_name is a name that can start with a digit
> 
> Luc Peuvrier
> 
> 
> 
> 
Received on Monday, 29 June 2009 17:19:39 GMT

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