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Re: SPARQL Grammar updated

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Thu, 29 Apr 2010 20:08:45 +0100
Message-ID: <4BD9D93D.6010504@talis.com>
To: Steve Harris <steve.harris@garlik.com>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>

On 26/04/2010 10:45 AM, Steve Harris wrote:
> On 2010-04-25, at 18:11, Andy Seaborne wrote:
>> * GROUP_CONCAT(?x,?y ; SEPARATOR=";")
>> At F2F3, we converged on this named parameters form of GROUP_CONCAT.  I suggested a uniform treatment with params available in custom aggregates. However, having tried this, I found it leads to complexity without obvious benefit.
>> Question:
>> Is this legal:
>>   GROUP_CONCAT(?x,?y ; SEPARATOR=?sep)
>> where ?sep is some in-scope variable?  For now, I've made the separator a fixed string depending clarification.
> I think constants only is a good idea. As I mentioned at the F2F, it otherwise raises a host of issues around grouped v's non-grouped values.

I'm happy to leave it as a fixed string.

> As everything after the ; is passed directly to the set function, that expression must either be GROUP BY ?sep, or it would have to be SAMPLE(?sep), or similar, and I don't really want to go there.

It could be made to work by requiring ?sep to be a variable in the group 
key (related to what is legal to project).

Received on Thursday, 29 April 2010 19:09:21 UTC

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