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Re: "in-scope" and BIND question

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Thu, 10 May 2012 10:06:48 +0100
Message-ID: <4FAB8528.6050200@epimorphics.com>
To: public-rdf-dawg@w3.org


On 09/05/12 15:27, Polleres, Axel wrote:
> I havea a question on in-scope variables and BIND, particularly, on item
> 12. in
> http://www.w3.org/2009/sparql/docs/query-1.1/rq25.xml#sparqlGrammar
> # " The variable assigned in a |BIND| clause must not be already in-scope
> <http://www.w3.org/TR/sparql11-query/#variableScope>.
> "
> I am not sure here, what "already" in-scope means. Can we clarify that?

Do you have suggestions? (I note the definition is based on your 
suggestions)

> Particularly, when reading the in-scope definition, I am a bit unsure of
> what happens
> with regards to e.g. UNION queries, i.e. my feeling is that
> SELECT *
> {
> { BIND (1 AS ?Y) }
> UNION
> { <s> <p> ?Y }
> }
> shouldn't be different from
> SELECT *
> {
> { <s><p> ?Y }
> UNION
> { BIND (1 AS ?Y) }
> }
> and both should be allowed (returning 1 on the empty graph), is that
> correct?

This is legal.  Scope as defined works bottom-up.

Maybe something needed for across a group?

	Andy

> thanks,
> Axel
> --
> Dr. Axel Polleres
> Siemens AG Österreich
> Corporate Technology Central Eastern Europe Research & Technologies
> CT T CEE
> Tel.: +43 (0) 51707-36983
> Mobile: +43 (0) 664 88550859
> Fax: +43 (0) 51707-56682 mailto:axel.polleres@siemens.com
Received on Thursday, 10 May 2012 09:07:21 GMT

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