Re: A proposal for basing quotation and annotation upon blank graphs

Another tricky one would be

:a :b %{g1}.
:s :p %{g1} %{g1}.

Should that be plainly disallowed? (I believe it should, but again, 
that's quite a burden on the parser)

On 12/10/2023 16:15, Pierre-Antoine Champin wrote:
>
> Thanks Andy. Out of curioty, what would you do of the following 
> N-Quads (again, using qnames for convenience only):
>
>     :s :p :o %{g1}
>
> Seems to me that this one has no asserted triple, only a "floating" 
> graph term...
>
> What about this one:
>
>     :s :p :o %{g1}.
>     :s :p :o %{g2}.
>     :a :b %{g1}.
>     :c :d %{g2}.
>
> Seems to be that this one would be equivalent (in the /abstract 
> syntax/) to
>
>     :s :p :o %{g1}.
>     :a :b %{g1}.
>     :c :d %{g1}.
>
> Do you agree? Could that be a problem (non trivial to detect)?
>
> On 12/10/2023 14:00, Andy Seaborne wrote:
>> I see using blank nodes as one possible implementation approach. The 
>> core idea is graph terms (types) and occurrences (tokens, uses of).
>>
>> I think we should focus on the whole model with draph terms in the 
>> RDF abstract data model; then see how we get there. Just looking at 
>> an incremental steps may leave RDF with the blocking legacy for "RDF 
>> 1.3".
>>
>> We can put quoted triples to one side for now and come back to them 
>> when the big picture is more settled.
>>
>>
>> Proposal: Syntactic support for graph terms.
>>
>> We need syntactic support for graph terms. Graph terms will be larger 
>> than our one line examples to date - 10s of triples and up. Visually 
>> seeing that two graphs are the same graph will be error prone.
>>
>>   _:a1 rdf:occurenceOf  { :s :p :o }
>>   _:a1 rdf:type ....
>>   _:a2 rdf:occurenceOf  { :s :p :o }
>>   _:a2 rdf:type ....
>>
>> And we need N-quads support.
>>
>> Suggestion: Have syntax to define a syntax element:
>>
>>   USING %{label} FOR { :s :p :o1, :o2 }
>>   _:a1 rdf:occurenceOf %{label}
>>   _:a1 rdf:type ....
>>   _:a2 rdf:occurenceOf %{label}
>>   _:a2 rdf:type ....
>>
>> with
>>
>>   _:a3 rdf:occurenceOf  { :s :p :o }
>>
>> is a shorthand for an implicitly generated %{....}. c.f. blank nodes.
>>
>> "label" is scoped to the document.
>>
>> There are many ways to have define-use syntax.  The form above keeps 
>> these aspects separate and the general style will naturally follow 
>> for other syntaxes we need to update.
>>
>> Unlike current TriG, a label is defined to stand for the graph, not a 
>> part of a graph.
>>
>> Now we can use URIs for tokens and that makes the occurrence and the 
>> type accessible over the web.
>> https://lists.w3.org/Archives/Public/public-rdf-star-wg/2023Oct/0009.html 
>>
>>
>> It is syntax. It is not in the RDF abstract data model. Graph terms 
>> are in the RDF abstract data model.
>>
>> This might be N-Quads (prefixed names for email only!). No USING needed.
>>
>>   # 4th slot. Grouping.
>>   :s :p :o1 %{g} .
>>   :s :p :o2 %{g} .
>>   # Use in object slot
>>   _:a1 rdf:occurrenceOf %{g} .
>>   # Use in subject slot
>>   %{g} :property "abc" .
>>
>> %{} is not a graph name.
>>
>>    :s :p :o1 %{g} .
>>
>> co-ops the use of the 4th slot but does not imply it is a graph name.
>> Nothing appears in GRAPH ?g {} .
>>
>> The form "%{ }" has many choices - {} is to suggest "graphs".
>>
>> JSON-LD use of blank node named graph is not affected.
>> Blank nodes could be used for a RDF 1.1 like implementation.
>>
>> rdf:occurrenceOf was used above because as Pierre-Antoine noted 
>> (SemTF) there are different kinds of "occurrence". Syntax that omits 
>> the name for the relationship is hiding this and it is something we 
>> have to explore.
>>
>> It may even become a keyword if there is one property but we aren't 
>> there yet.
>>
>>     Andy
>>