- From: Alexandre Passant <alexandre.passant@deri.org>
- Date: Wed, 31 Mar 2010 11:55:59 +0100
- To: Andy Seaborne <andy.seaborne@talis.com>
- Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
On 31 Mar 2010, at 11:35, Andy Seaborne wrote:
>
>
> On 31/03/2010 11:11 AM, Alexandre Passant wrote:
>>
>> On 31 Mar 2010, at 09:13, Andy Seaborne wrote:
>>
>>> Should the syntax of MINUS be like UNION with {} on the left-hand side
>>>
>>> { { ?s a foaf:Person
>>> ?s foaf:name ?name
>>> }
>>> MINUS
>>> { ?s foaf:knows ?other }
>>> }
>>>
>>> or without:
>>>
>>> { ?s a foaf:Person .
>>> ?s foaf:name ?name .
>>> MINUS { ?s foaf:name ?name }
>>> }
>>
>> My preference for the second one, saves a few editing process when adding / removing a MINUS clause from an existing query.
>
> For the record, we could change UNION to allow {}-less LHS
>
> A chain of UNIONs would be
>
> pattern UNION { pattern } UNION { pattern }
Would be nice indeed.
Alex.
>
> This has no effect on SPARQL 1.0 style queries.
>
> { pattern } UNION { pattern } UNION { pattern }
>
> is still legal and the same semantics. It's just a tweak to the grammar - the same AST and same algebra would result.
>
> (Ditto any future INTERSECTION which would presumably be the same as doing a join and projecting to common variables in SPARQL).
>
> Andy
>
--
Dr. Alexandre Passant
Digital Enterprise Research Institute
National University of Ireland, Galway
:me owl:sameAs <http://apassant.net/alex> .
Received on Wednesday, 31 March 2010 11:00:16 UTC