Re: SHACL to SPARQL

Thanks for the links, I'll have a play with those and see if I can generate
the sorts of queries I'm using.
I was linked to some work recently
https://github.com/hypermedia-app/shape-to-query which had similar
extensions to what I've added e.g.
https://shape-to-query.hypermedia.app/docs/#extension-spo-rule - this
prompted me to ask.

The other context for the work I'm doing is it needs to combine a number of
things to generate SPARQL queries, some of which are specified in SHACL,
some not. To do this I've implemented the SPARQL Grammar as a set of Python
Pydantic models (
https://github.com/Kurrawong/sparql-grammar-pydantic/tree/david/wip-complete-grammar/sparql_grammar_pydantic),
which makes it conceptually easy/safe to merge the different inputs and
generate valid/performant SPARQL queries. I might look to extend one of the
existing libraries to optionally produce SPARQL Grammar.

On Tue, Sep 24, 2024 at 5:43 AM Kurt Cagle <kurt.cagle@gmail.com> wrote:

> Also, Flores Bakker has been working on an rdf representation of sparql
> that is coming along very well. There may be some overlap here.
>
> On Mon, Sep 23, 2024, 12:40 Kurt Cagle <kurt.cagle@gmail.com> wrote:
>
>> This looks like it may be incredibly useful.
>>
>> On Mon, Sep 23, 2024, 12:07 Vladimir Alexiev <
>> vladimir.alexiev@ontotext.com> wrote:
>>
>>> These may be useful:
>>>
>>> https://shape-fragments.github.io/shape-fragments-spec/
>>> https://github.com/Shape-Fragments/SHACL2SPARQL
>>> https://github.com/MaximeJakubowski/ssf_project
>>> https://github.com/MaximeJakubowski/sls_project
>>>
>>>
>>> On Mon, Sep 23, 2024 at 2:57 PM David Habgood <dcchabgood@gmail.com>
>>> wrote:
>>>
>>>> Hi all,
>>>>
>>>> I have a library which generates SPARQL queries from SHACL, mostly to
>>>> support two use cases. The first is listing sets of items, or focus nodes,
>>>> with constraints on which items are selected. I find this one quite
>>>> straightforward in SHACL. The second is describing individual objects, i.e.
>>>> which properties should be included/and or excluded when describing an
>>>> individual focus node. This one I find less clear - I can see there are a
>>>> series of SHACL predicates which are relevant, but it's unclear to me if
>>>> there's a "canonical" way this should be done.
>>>>
>>>> My question is whether there's a canonical way to do Use Case 2, and if
>>>> not, should this form part of the use cases SHACL covers in future or be a
>>>> part of a SHACL extension.
>>>>
>>>> In detail my use cases are:
>>>>
>>>> Use Case 1:
>>>> I want to describe the selection of a set of focus nodes, based on one
>>>> or a combination of the following focus node attributes:
>>>> - the class of the focus nodes
>>>> - the focus nodes' relationship to a specified node (e.g. is member of
>>>> x)
>>>> - the focus nodes' relationship to nodes of a specified class (e.g. the
>>>> dcat:Catalogs that contain any dcat:Dataset, dcat:Resource etc.)
>>>> - the presence or abscence of properties on the focus nodes, including
>>>> via path relations (inverse, sequence etc.)
>>>>
>>>> Use Case 2:
>>>> I want to describe a focus node by choosing one of the following two
>>>> methods:
>>>> 1.
>>>> a. including all direct properties, except:
>>>> - excluding any properties explicitly stated including via path
>>>> relations (inverse, sequence etc.). (e.g. when describing a dcat:Dataset,
>>>> not listing it's large number of members)
>>>> - including any properties explicitly stated via "indirect" path
>>>> relations (inverse, sequence etc.)
>>>> b. inclusion of blank nodes to a specified depth
>>>>
>>>> 2.
>>>> a. excluding all direct/indirect properties, except:
>>>> - including any properties explicitly stated via direct and indirect
>>>> path relations (inverse, sequence etc.)
>>>> b. inclusion of blank nodes to a specified depth
>>>>
>>>> If SHACL predicates are reused across both use cases I want a clear way
>>>> to distinguish which they are being used for. E.g. is a SHACL expression
>>>> which in some way specifies dcterms:hasPart being used to describe how to
>>>> select a set of focus nodes, or how to describe each focus node. At present
>>>> I've used extension predicates for the blank node depth and "include all
>>>> properties" concepts.
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>