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Re: Definition of FilteredBasicGraphPattern in SPARQL grammar

From: Arjohn Kampman <arjohn.kampman@aduna-software.com>
Date: Thu, 26 Oct 2006 20:57:41 +0200
Message-ID: <45410525.8000904@aduna-software.com>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
CC: public-rdf-dawg-comments@w3.org

Seaborne, Andy wrote:
> -------- Original Message --------
>> From: Arjohn Kampman <>
>> Date: 26 October 2006 16:48
>>
>> It took me quite some time to understand the production rule for
>> FilteredBasicGraphPattern in the SPARQL grammar, due to the
>> recursiveness of the definition. I think this production rule
>> in combination with BlockOfTriples can be reformulated to one of the
>> following, much simpler, definitions:
>>
>> FilteredBasicGraphPattern ::=
>>          ( (TriplesSameSubject|Constraint) '.'? )*
>>
>> As far as I can see, there is only one difference between these rules
>> and the rules from the grammar: The rules from the grammar allow
>> multiple dots after TriplesSameSubject blocks and zero or one dot
> after
>> Constraint blocks, whereas the above rule only allows zero or one dot
>> after both blocks. Alternatively, the above rule can be slightly
>> modified to allow multiple dots after (both) blocks.
>>
>> --
>> Arjohn Kampman, Senior Software Engineer
>> Aduna - Guided Exploration
>> www.aduna-software.com
> 
> Arjohn,
> 
> Thanks for the observation.
> 
> [22] BlockOfTriples ::=
> 	TriplesSameSubject ( '.' TriplesSameSubject? )*
> 
> should be 
> 
> [22'] BlockOfTriples ::=
> 	TriplesSameSubject ( '.' BlockOfTriples? )?

OK, that makes sense. Thanks for the quick reply.

Arjohn
Received on Thursday, 26 October 2006 18:58:04 GMT

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