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Re: Proposed: SPARQL grammar is complete as-is

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Fri, 31 Dec 2010 13:19:59 +0000
Message-ID: <4D1DD87F.9080105@epimorphics.com>
To: Steve Harris <steve.harris@garlik.com>
CC: Lee Feigenbaum <lee@thefigtrees.net>, SPARQL Working Group <public-rdf-dawg@w3.org>


On 23/12/10 12:09, Steve Harris wrote:
> On 2010-12-23, at 11:58, Andy Seaborne wrote:
>>>
>>> I had an action to look at including CONSTRUCT WHERE { ... } for commonality with DELETE WHERE. I've not done anything about that, but it looks to me like it could be included as:
>>>
>>> 'CONSTRUCT WHERE' GroupGraphPattern SolutionModifier
>>
>> See discussion:
>> http://lists.w3.org/Archives/Public/public-rdf-dawg/2010OctDec/0462.html
>
> I completely forgot that.
>
> In that case, modulo the stuff I've already mentioned, I think it's OK.
>
> - Steve

In the spirit of facts, and not mere guesswork, I went back and checked 
on the implications of a "CONSTRUCT WHERE" short form.  It's doable: my 
fears were unfounded.

Based on the discussion around DELETE WHERE, I have only considered a 
BGP or construct template for the WHERE clause.  No FILTER, no other 
graph patterns.

It's not quite like DELETE WHERE because of FROM/FROM NAMED.

It can be done by only changing the rule for CONSTRUCT:

[9]   	ConstructQuery 	  ::=
  'CONSTRUCT'
  (
    # The original rule
    ConstructTemplate DatasetClause* WhereClause SolutionModifier
    |
    # The short form.
    DatasetClause* 'WHERE' '{' TriplesTemplate? '}' SolutionModifier
  )

It may be possible to tidy this up.

In the short form WHERE is mandatory - this enables the parser to know 
it's skipped the template in the full form.

Therefore, I think we should put this in.  The extra editing is quite 
small - adding a short para and example query to the CONSTRUCT section.

	Andy
Received on Friday, 31 December 2010 13:20:40 GMT

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