Re: ISSUE-139: implementing (core) constraint components universally

On 6/3/16 5:14 PM, Holger Knublauch wrote:
>> Having a single implementation of each constraint component would
>> actually
>> reduce development costs.  Ideally, this single implementation would
>> be as
>> simple as the ask validators that implement many constraint components.
>> Consider, for example, sh:minCount whose implementation should be very
>> little more than "HAVING ( COUNT (DISTINCT ?value) < ?minCount )".
>
> Yes, if this were possible then this would be ideal.
>
>>    However,
>> I can't figure out how to do this nicely because of limitations in
>> SPARQL,
>> hence the solution with boilerplate.
>
> Exactly that's the same conclusion that I also have made. Furthermore I
> remember long discussions with Arthur on the phone in November. He had
> also questioned why we cannot combine all these cases. But he also did
> not come up with a better solution. If all three of us don't come up
> with a solution then maybe there is none.

There is no requirement that SHACL be implementable with SPARQL. We 
agreed to express the formalisms in SPARQL "where appropriate" but that 
is the only connection between SPARQL and SHACL. If SPARQL turns out not 
to be suitable as a defining technology, then we should abandon that 
resolution, or be more open about identifying the "where not 
appropriate" part of the resolution.

kc

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
m: 1-510-435-8234
skype: kcoylenet/+1-510-984-3600

Received on Saturday, 4 June 2016 18:57:44 UTC