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Re: ISSUE-41: Property paths

From: Simon Steyskal <simon.steyskal@wu.ac.at>
Date: Thu, 10 Mar 2016 07:05:46 +0100
To: Holger Knublauch <holger@topquadrant.com>
Cc: public-data-shapes-wg@w3.org
Message-ID: <2daa135969732da7f7a77cc2628aba0d@wu.ac.at>
Hi!

> If we wanted to support this while preserving the usefulness of SHACL
> for data description (form building etc), we could for example just
> add a new kind of constraint such as
> 
> ex:MyShape
>     a sh:Shape ;
>     sh:pathConstraint [
>         sh:path [ a sh:SPARQLPath ; sh:sparql "rdf:rest*/rdf:first" ] ;
>         sh:class ex:Something ;
>     ] .

yes, I would definitely prefer such a "lightweight" version over adding 
an entirely new path construct (e.g., sh:Path, sh:AltPath, ...).

simon

---
DDipl.-Ing. Simon Steyskal
Institute for Information Business, WU Vienna

www: http://www.steyskal.info/  twitter: @simonsteys

Am 2016-03-09 07:36, schrieb Holger Knublauch:
> If we wanted to support this while preserving the usefulness of SHACL
> for data description (form building etc), we could for example just
> add a new kind of constraint such as
> 
> ex:MyShape
>     a sh:Shape ;
>     sh:pathConstraint [
>         sh:path [ a sh:SPARQLPath ; sh:sparql "rdf:rest*/rdf:first" ] ;
>         sh:class ex:Something ;
>     ] .
> 
> This could be limited to the extension mechanisms to keep the core
> language reasonably sized, avoiding topics like recursion all over
> again.
> 
> Holger
> 
> 
> On 9/03/2016 16:17, Simon Steyskal wrote:
>> Hi!
>> 
>> as for 2) we may want to consider re-opening issue-41 "Using property 
>> paths to refer to values/types?" [1]
>> (which I would be very very happy about)
>> 
>> [1] https://www.w3.org/2014/data-shapes/track/issues/41
>> 
>> simon
>> ---
>> DDipl.-Ing. Simon Steyskal
>> Institute for Information Business, WU Vienna
>> 
>> www: http://www.steyskal.info/  twitter: @simonsteys
>> 
>> Am 2016-03-09 07:02, schrieb Holger Knublauch:
>>> I see three main areas of differences between current SHACL and your 
>>> draft:
>>> 
>>> 1) Shall the concepts Shape and Constraint be merged (syntactic 
>>> sugar)
>>> 2) Shall SHACL constraints support arbitrary property paths instead 
>>> of
>>> property/inverseProperty
>>> 3) Shall constraint parameters be limited to a single property only
>>> 
>>> Leaving aside the specific triples, does anyone see other major 
>>> differences?
>>> 
>>> The ISSUE-133 that you raised is limited to 3) and it may be worth
>>> having separate issues for the two other differences, if only to
>>> structure the discussion.
>>> 
>>> I do not believe that there are necessary dependencies between these
>>> areas, and it would IMHO be more fruitful to look at them
>>> individually, because there are different variations even of the
>>> existing syntax conceivable. I do not understand why you elected to
>>> start everything from scratch.
>>> 
>>> Holger
>>> 
>>> 
>>> On 9/03/2016 9:03, Peter F. Patel-Schneider wrote:
>>>> See
>>>> https://www.w3.org/2014/data-shapes/wiki/ISSUE-95:_Metamodel_simplifications#Proposal_4 
>>>> On 03/06/2016 06:24 PM, Holger Knublauch wrote:
>>>>> Peter,
>>>>> 
>>>>> I understand this is largely just a sketch and you may be "thinking 
>>>>> out loud".
>>>>> Yet I don't have sufficient information on how all this is supposed 
>>>>> to work,
>>>>> e.g. with SPARQL generation. It would help if you could provide 
>>>>> some examples
>>>>> of how this vocabulary would be used to define some built-in and 
>>>>> extension
>>>>> constraint types. On
>>>>> 
>>>>> https://www.w3.org/2014/data-shapes/wiki/ISSUE-95:_Metamodel_simplifications#Proposal_3 
>>>>> I am presenting snippets illustrating the definitions of
>>>>> ex:LanguageConstraintType, sh:PatternConstraintType and
>>>>> sh:ClassConstraintType. Would you mind creating similar examples in 
>>>>> your
>>>>> metamodel?
>>>>> 
>>>>> Furthermore, I am unclear what problem you are trying to solve. 
>>>>> What is broken
>>>>> in the current SHACL syntax that motivates your (radical) changes? 
>>>>> Have any
>>>>> users complained or are there any related ISSUEs recorded? Of 
>>>>> course we can
>>>>> come up with any number of syntaxes for SHACL and I could certainly 
>>>>> make up
>>>>> plenty of variations, too.
>>>>> 
>>>>> Thanks,
>>>>> Holger
>>>>> 
>>>>> 
>>>>> On 5/03/2016 13:32, Peter F. Patel-Schneider wrote:
>>>>>> I fixed up some silly syntax errors and added prefix declarations. 
>>>>>>  The
>>>>>> attached file looks OK to the syntax checker I grabbed.
>>>>>> 
>>>>>> peter
>>>>>> 
>>>>>> 
>>>>>> On 03/04/2016 04:29 PM, Holger Knublauch wrote:
>>>>>>> Turtle file doesn't parse. Could you fix this?
>>>>>>> 
>>>>>>> Thanks,
>>>>>>> Holger
>>>>>>> 
>>>>>>> 
>>>>>>> On 5/03/2016 10:17, Peter F. Patel-Schneider wrote:
>>>>>>>> On 03/03/2016 04:20 PM, Holger Knublauch wrote:
>>>>>>>>> If you want this to be
>>>>>>>>> seriously considered, please work out the details, including 
>>>>>>>>> Turtle files
>>>>>>>>> etc.
>>>>>>>>> Holger
>>>>>>>> OK, since you asked so nicely, see the two attached files.
>>>>>>>> 
>>>>>>>> peter
>>>>>>>> 
>>>>> 
Received on Thursday, 10 March 2016 06:06:14 UTC

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