Re: Summary: Annotation Syntax Proposals

- I would stay away from { } because of the connotation with graphs in N3
and Trig and some of the constructs in SPARQL. All of them have complete
triple statements that include a subject. IMO the use of * or | doesn't
really make that super clear.

Trig          :a { :x :y :z } but I can't write :a { :y :z }
N3            :a :b { :x :y :z } but I can't write :a :b { :y :z }
SPARQL  WHERE { :x :y :z } but I can't write WHERE { :y :z }
RDF* .     :a :b :c *{ :y :z } but I can't write :a :b :c *{ :x :y :z }

If you want to stick to something like that, *[ ] would be more uniform
(but that would probably cause issues with blanknode parsing )

- Another (minor) concern I have about annotations in a fourth position is
that it breaks the pattern introduced by all other syntaxes (with the
exception Trig). They all note things down in three (= triples) or four (=
quads) parts, shorthand syntax included.

<< :subject :predicate :object >>  :source :URL  . -> 3 parts
{| :subject :predicate :object |}  :source :URL  . -> 3 parts

:subject :predicate :object {| :source :URL |} . -> 4 parts
:subject :predicate :object @{ :source :URL } .-> 4parts

N-Triples/N-Quads are indeed something else, but let's not ignore the
patterns they have already introduced.  Also, Turtle is superset of
N-Triples, Trig & N3 are supersets of Turtle and N-Quads is a superset of
N-Triples - shouldn't we guarentee that future RDF* extensions of these
syntaxes remain feasible (eg. getting into shorthand hell) and without
diverging too much from these superset relations. Something that has four
parts reads like a quad to me. But this is just personal preference.



Op wo 20 jan. 2021 om 00:51 schreef Holger Knublauch <holger@topquadrant.com
>:

>
> 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?
>
> Holger
>
>
>
>