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Posted to users@jena.apache.org by Martynas Jusevičius <ma...@atomgraph.com> on 2021/01/02 17:48:59 UTC

TriX default

Hi,

some time ago we had an issue re. TriX:
https://issues.apache.org/jira/browse/JENA-1211

I was looking at the W3C DTD again, specifically for <graph> elements:

<!ELEMENT graph        (uri, triple*)>

This made me wonder how the default graph should be represented if it
has no URI.

My understanding was that the default <graph> should have no <uri>,
but the W3C DTD contradicts this.
I was probably thinking about the HP's DTD version [1] where the
<graph> definition was different (though still looks wrong with an
unbounded number of URIs):

<!ELEMENT graph (uri*, triple*)>

A quick test with riot CLI converts N-Triples

<http://s> <http://b> <http://c> .

to

<trix xmlns="http://www.w3.org/2004/03/trix/trix-1/">
  <graph>
    <triple>
      <uri>http://s</uri>
      <uri>http://b</uri>
      <uri>http://c</uri>
    </triple>
  </graph>
</trix>

Isn't this invalid in respect to the W3C DTD?

It's quite unfortunate that we have those 2 incompatible versions and
neither of them seems to get it right...

[1] https://www.hpl.hp.com/techreports/2004/HPL-2004-56.pdf


Martynas
atomgraph.com

Re: TriX default

Posted by Andy Seaborne <an...@apache.org>.


On 03/01/2021 11:25, Martynas Jusevičius wrote:
> I’ll see what RDF4J does.
> 
> I think ultimately the reasonable solution would be to have
> 
> <!ELEMENT graph        (uri?, triple*)>
> 
> as the DTD.

Indeed - that's what's implemented!

     Andy

> 
> On Sun, 3 Jan 2021 at 11.38, Andy Seaborne <an...@apache.org> wrote:
> 
>> What do other systems do?
>>
>> Everything else is secondary given that (W3C|HPLB)-trix is not a working
>> group, or community group, consensus.
>>
>> (IIRC the Jena reader doesn't care about namespaces)
>>
>>       Andy
>>
>> On 02/01/2021 17:48, Martynas Jusevičius wrote:
>>> Hi,
>>>
>>> some time ago we had an issue re. TriX:
>>> https://issues.apache.org/jira/browse/JENA-1211
>>>
>>> I was looking at the W3C DTD again, specifically for <graph> elements:
>>>
>>> <!ELEMENT graph        (uri, triple*)>
>>>
>>> This made me wonder how the default graph should be represented if it
>>> has no URI.
>>>
>>> My understanding was that the default <graph> should have no <uri>,
>>> but the W3C DTD contradicts this.
>>> I was probably thinking about the HP's DTD version [1] where the
>>> <graph> definition was different (though still looks wrong with an
>>> unbounded number of URIs):
>>>
>>> <!ELEMENT graph (uri*, triple*)>
>>>
>>> A quick test with riot CLI converts N-Triples
>>>
>>> <http://s> <http://b> <http://c> .
>>>
>>> to
>>>
>>> <trix xmlns="http://www.w3.org/2004/03/trix/trix-1/">
>>>     <graph>
>>>       <triple>
>>>         <uri>http://s</uri>
>>>         <uri>http://b</uri>
>>>         <uri>http://c</uri>
>>>       </triple>
>>>     </graph>
>>> </trix>
>>>
>>> Isn't this invalid in respect to the W3C DTD?
>>>
>>> It's quite unfortunate that we have those 2 incompatible versions and
>>> neither of them seems to get it right...
>>>
>>> [1] https://www.hpl.hp.com/techreports/2004/HPL-2004-56.pdf
>>>
>>>
>>> Martynas
>>> atomgraph.com
>>>
>>
>

Re: TriX default

Posted by Martynas Jusevičius <ma...@atomgraph.com>.

I’ll see what RDF4J does.

I think ultimately the reasonable solution would be to have

<!ELEMENT graph        (uri?, triple*)>

as the DTD.

On Sun, 3 Jan 2021 at 11.38, Andy Seaborne <an...@apache.org> wrote:

> What do other systems do?
>
> Everything else is secondary given that (W3C|HPLB)-trix is not a working
> group, or community group, consensus.
>
> (IIRC the Jena reader doesn't care about namespaces)
>
>      Andy
>
> On 02/01/2021 17:48, Martynas Jusevičius wrote:
> > Hi,
> >
> > some time ago we had an issue re. TriX:
> > https://issues.apache.org/jira/browse/JENA-1211
> >
> > I was looking at the W3C DTD again, specifically for <graph> elements:
> >
> > <!ELEMENT graph        (uri, triple*)>
> >
> > This made me wonder how the default graph should be represented if it
> > has no URI.
> >
> > My understanding was that the default <graph> should have no <uri>,
> > but the W3C DTD contradicts this.
> > I was probably thinking about the HP's DTD version [1] where the
> > <graph> definition was different (though still looks wrong with an
> > unbounded number of URIs):
> >
> > <!ELEMENT graph (uri*, triple*)>
> >
> > A quick test with riot CLI converts N-Triples
> >
> > <http://s> <http://b> <http://c> .
> >
> > to
> >
> > <trix xmlns="http://www.w3.org/2004/03/trix/trix-1/">
> >    <graph>
> >      <triple>
> >        <uri>http://s</uri>
> >        <uri>http://b</uri>
> >        <uri>http://c</uri>
> >      </triple>
> >    </graph>
> > </trix>
> >
> > Isn't this invalid in respect to the W3C DTD?
> >
> > It's quite unfortunate that we have those 2 incompatible versions and
> > neither of them seems to get it right...
> >
> > [1] https://www.hpl.hp.com/techreports/2004/HPL-2004-56.pdf
> >
> >
> > Martynas
> > atomgraph.com
> >
>

Re: TriX default

Posted by Andy Seaborne <an...@apache.org>.

What do other systems do?

Everything else is secondary given that (W3C|HPLB)-trix is not a working 
group, or community group, consensus.

(IIRC the Jena reader doesn't care about namespaces)

     Andy

On 02/01/2021 17:48, Martynas Jusevičius wrote:
> Hi,
> 
> some time ago we had an issue re. TriX:
> https://issues.apache.org/jira/browse/JENA-1211
> 
> I was looking at the W3C DTD again, specifically for <graph> elements:
> 
> <!ELEMENT graph        (uri, triple*)>
> 
> This made me wonder how the default graph should be represented if it
> has no URI.
> 
> My understanding was that the default <graph> should have no <uri>,
> but the W3C DTD contradicts this.
> I was probably thinking about the HP's DTD version [1] where the
> <graph> definition was different (though still looks wrong with an
> unbounded number of URIs):
> 
> <!ELEMENT graph (uri*, triple*)>
> 
> A quick test with riot CLI converts N-Triples
> 
> <http://s> <http://b> <http://c> .
> 
> to
> 
> <trix xmlns="http://www.w3.org/2004/03/trix/trix-1/">
>    <graph>
>      <triple>
>        <uri>http://s</uri>
>        <uri>http://b</uri>
>        <uri>http://c</uri>
>      </triple>
>    </graph>
> </trix>
> 
> Isn't this invalid in respect to the W3C DTD?
> 
> It's quite unfortunate that we have those 2 incompatible versions and
> neither of them seems to get it right...
> 
> [1] https://www.hpl.hp.com/techreports/2004/HPL-2004-56.pdf
> 
> 
> Martynas
> atomgraph.com
>