Re: shapes-ISSUE-168 (instance count): How to constrain number of instances of a class in a graph [SHACL - Core]

On 14/06/2016 14:30, Dimitris Kontokostas wrote:
>
>     The general problem with scope-based constraints is that scopes
>     are only one way to trigger validation. Other cases include nested
>     shapes (sh:shape, sh:or etc) and (as in ShEx) to have some
>     dedicated root shape or (as in Arthur's use cases, if I may speak
>     on his behalf) control the validation process completely outside
>     of the model, from some application-specific algorithm. So
>     anything that behaves differently depending on whether it has a
>     scope or not is bound to fail.
>
>
> I do not think this is a problem but a feature, every constraint can 
> have a scope that is direct (sh:scope*), indirect (from sh:shape, 
> sh:or etc) or manual (from validation).
> If we treat constraints & scopes like this everything becomes much 
> simpler.

I have tried to capture this question in a proposal

https://www.w3.org/2014/data-shapes/wiki/Proposals#Topic_3:_Size_of_value_nodes_set_for_node_constraints

Also related to ISSUE-168. I have not yet had time to think through all 
the technical implications of such a change, and what variation would be 
more intuitive to users.

Holger