Re: Summary: Annotation Syntax Proposals

On 19/01/2021 23:50, Holger Knublauch wrote:
> 
> On 2021-01-20 4:10 am, Andy Seaborne wrote:
>> + Is nesting allowed in the annotationBlock? that is, be able to add 
>> annotations to the extra triples inside the annotation block? 
>> (Technical consequence: if not, then the Turtle grammar has to have 
>> more changes to exclude this possibility by having versions of some 
>> grammar rules with and without the annotation syntax, and also in the 
>> grammar rules a production uses. Annotation is part of 
>> predicateObjectList.
>>
>> Nesting requires a delimiter style - mark the start and end of the 
>> annotation block.
> 
> Has the RDF* group agreed that nesting should be supported in general? I 
> would consider this feature rather unnecessary. Allowing multiple levels 
> of annotations (i.e. reification of reified triples) puts extra burden 
> on developers who then need to create UIs and other algorithms around 
> those cases. And how many of the users are going to understand these 
> constructs?

re: "algorithms"

Annotation syntax is "syntactic sugar". The data may have the forms in 
it anyway - it would take a change to the RDF abstract data model to 
exclude it.


Nesting happens because an annotationBlock is using PredicateObjectList.

Take a look at TriplesSameSubject and TriplesSameSubjectPath and all the 
derived with/without "Path" rules in the SPARQL grammar. 
PropertyListPathNotEmpty,TriplesNodePath, PropertyListPath  etc etc.

This is what is used to have paths only in WHERE{} and not 
CONSTRUCT/INSERT/DELETE templates - it makes the grammar bigger - for 
Turtle, it means there are two parallel grammars for "triples".


The SPARQL 1.1 WG decided not to do the same for expressions where there 
are two cases (with and without aggregates) because the grammar size 
explodes. It is covered by a grammar note 14.

That is what makes

     BIND(Count(*) AS ?C)

illegal syntax, not the grammar itself.

     Andy

> 
> Holger
> 
> 
>

Received on Wednesday, 20 January 2021 10:56:24 UTC