Re: sh:allowedValues and skos:Collection

On 8/18/2015 2:04, Miika Alonen wrote:
> This is related to the ISSUE-80, but still separate matter.
>
> One way of referencing classifications etc. would be to create lists 
> from existing concepts. However, if you create such lists then you 
> should also describe how the list is created and add some human 
> readable documentation to it. I tried to think of a way to validate 
> data that references to members in skos:Collection. You could validate 
> skos:Collections with skos:member using inverse property constraints, 
> but skos:memberList is bit difficult. I tried to refence the same list 
> (blank node) in both skos:memberList and sh:allowedValues but it seems 
> that its a bad idea.
>
> Could it be possible to support instances of skos:Collection with the 
> sh:allowedValues predicate? Allowed values could come from the list 
> defined by skos:memberList. This would also mean that you could reuse 
> the same value lists in multiple constraints. Same functionality could 
> also be achieved by creating similar sh:Collection and sh:memberList 
> to the SHACL specification.

I believe this is technically no problem, although I would prefer to 
introduce a new keyword such as sh:allowedValuesCollection. But a 
question is whether SHACL can/should support on anything from the SKOS 
namespace. SKOS is popular and well-established, and I think it would be 
better to reuse skos:Collection instead of creating yet another 
variation of it. However, the layering feels a bit weird for the SHACL 
Core Language. For example, if we were to add SKOS constraints, then why 
not schema:Enumeration or Hydra Collection?

I don't want to sound like a broken record, but I believe such things 
would be best handled by a separate SHACL vocabulary, such as 
SHACL-SKOS. That library could also hold the other SKOS-related 
constraints, such as those captured as User Story 21:

http://www.w3.org/TR/2015/WD-shacl-ucr-20150414/#uc21-skos-constraints

Such work could be outsourced to a corresponding special interest group.

Holger