Support for OpenLink Virtuoso

[fonji]

Hello!

We changed our server to use OpenLink Virtuoso (because reasons), which is a bit meticulous.

Virtuoso doesn't like this query:

DESCRIBE ?uri WHERE {
  SELECT DISTINCT ?uri ?graph WHERE { 
    GRAPH ?graph { 
      ?uri a <http://www.w3.org/2004/02/skos/core#Concept> . 
      ?uri ?p ?o . 
      FILTER(?uri = <http://www.isyrare.fr/bamara/disease#93593> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98666> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#79207> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98711> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98713>
      ) 
    } 
  } 
}

It will respond

37000 Error SP030: SPARQL compiler, line 2: syntax error at 'SELECT' before 'DISTINCT'

Solution is to use double {{ }}:

DESCRIBE ?uri WHERE {{ 
  SELECT DISTINCT ?uri ?graph WHERE { 
    GRAPH ?graph { 
      ?uri a <http://www.w3.org/2004/02/skos/core#Concept> . 
      ?uri ?p ?o . 
      FILTER(?uri = <http://www.isyrare.fr/bamara/disease#93593> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98666> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#79207> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98711> 
        || ?uri = <http://www.isyrare.fr/bamara/disease#98713>
      ) 
    } 
  } 
}}

And then it's happy.
I don't know how other servers will react to this, but I patched my fork anyway.
Here's the commit.

Hope this helps.
Stay tuned, I still have stuff that doesn't want to work nicely. But it will.

[fonji]

Nevermind the other problems. After first investigation it seems to be more a rails 4 problem than a virtuoso one.
I'll keep you up to date.

[fonji]

#20 duplicate. Sorry.