Re: SHACL syntax and metamodel complexity

"fillers" = "values"?

On 2/24/16 9:03 AM, Peter F. Patel-Schneider wrote:
> SHACL states property constraints in the following way
>
>    for the fillers of property ex:p
>    the special fillers must all belong to class ex:s,
>    there must be at least one,
>    there must be at least five special fillers,
>    they must all be either ex:a, ex:b, ex:c, ex:d, ex:e, ex:f, ex:d, ex:h,
>      ex:i, or ex:j,
>    there must be at most ten,
>    the identifiers used for them must match regular expression r,
>    they must all belong to class ex:c, and
>    there must be at most seven special fillers.
>
> but not in the following way
>
>    for the fillers of property ex:p
>    there must be at least one,
>    they must all belong to class ex:c,
>    there must be at most five,
>    they must all belong to class ex:d, and
>    there must be at least three.
>
> In my opinion, these features of the SHACL RDF syntax are contributing to
> the complexity of the SHACL metamodel and to the number of decisions that
> have to be made to construct the SHACL metamodel.
>
>
> If SHACL stated constraints in the following way
>
>    there must be at least one filler of property ex:p,
>    all the fillers of property ex:p must belong to class ex:c,
>    there must be at most five fillers of property ex:p,
>    all the fillers of property ex:p must belong to class ex:d, and
>    there must be at least three fillers of property ex:p.
>
> then the the metamodel for SHACL constraints could have just particular
> constraints (from the clauses above and other constraint constructs).  This
> would be a significant simplification of the metamodel.
>
>
> Even if SHACL permitted the second construction above and uniformly stated
> multi-part particular constraints as at the end of the following there might
> be significant simplifications of the metamodel
>
>    for the fillers of property ex:p
>    there must be at least one,
>    they must all be either ex:a, ex:b, ex:c, ex:d, ex:e, ex:f, ex:d, ex:h,
>      ex:i, or ex:j,
>    there must be at most ten,
>    the identifiers used for them must match regular expression r,
>    they must all belong to class ex:c, and
>    there must be at between five and seven fillers that belong to class ex:s.
>
>
> These simplifications would require changes to the RDF syntax of SHACL.
>
> peter
>
>

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

Received on Wednesday, 24 February 2016 17:54:17 UTC