W3C home > Mailing lists > Public > public-data-shapes-wg@w3.org > March 2015

Re: How would option b) on the last straw poll of 12 March work?

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Mon, 16 Mar 2015 04:57:17 -0700
Message-ID: <5506C51D.1070105@gmail.com>
To: Eric Prud'hommeaux <eric@w3.org>
CC: RDF Data Shapes Working Group <public-data-shapes-wg@w3.org>
Hash: SHA1

On 03/15/2015 07:07 PM, Eric Prud'hommeaux wrote:
> cherry-picking the easy stuff 'cause i'm rather late for bed.
> * Peter F. Patel-Schneider <pfpschneider@gmail.com> [2015-03-15
> 18:24-0700]
>> On 03/15/2015 05:39 PM, Eric Prud'hommeaux wrote:
>>> * Peter F. Patel-Schneider <pfpschneider@gmail.com> [2015-03-15 
>>> 12:55-0700]
>>>> A few questions and comments.
>>>> Is this the entirety of SHACL or just the core language?  The
>>>> language here does not cover closed shapes, exclusive or, global
>>>> constraints, maximum cardinality of 0, non-datatype type matching,
>>>> or datatype facets.
>>> Agreed, it seemed wisest to start with a conservative subset and
>>> add.
>> The problem is that adding may be problematic or impossible.  How, for 
>> example, is this account going to handle closed shapes or global
>> constraints or extension via SPARQL code?
> Closed shapes can be implemented if `triple constraint matches` returns a
> set of passing and failing triples and `shape matches` subtracts the
> passing from the failing, returning true if their are no more failing
> triples. `and constraint matches` returns all of the passing and failing
> and `or constraint matches` returns those from the passing disjuncts.

I don't think that this works correctly, or at least it runs counter to my
intuitions as to what closed shapes are supposed to do.  Consider a shape like
  S1 = and ( property p shape S2 ;
	     property p shape S3 )
  S2 = property q
  S3 = property r
It seems to me that this should be a closed match to
  x p y .
  y q a .
  y r b .
but the S2 and S3 matches will return false.


Version: GnuPG v1

Received on Monday, 16 March 2015 11:57:47 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:30:17 UTC