RDF::Query: broken local name if prefixes overlap

[nichtich]

use v5.14;
use RDF::Query;
say RDF::Query->new(join "", <DATA>)->as_sparql;
__DATA__
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX ps: <http://www.wikidata.org/prop/statement/>
SELECT * WHERE {
    ?id p:P1549 ?statement .
    ?statement ps:P1549 ?label .
}

Expect query as given above but got:

PREFIX p: <http://www.wikidata.org/prop/>
PREFIX ps: <http://www.wikidata.org/prop/statement/>
SELECT * WHERE {
    ?id p:P1549 ?statement .
    ?statement p:statement/P1549 ?label .
}

which is invalid because p:statement/P1549 is not IRI and should be ps:P1549.

I am sorry to say: RDF::Query is great for query execution but seems to be a bit too buggy for my use case (parsing, inspecting and pretty-printing SPARQL queries). Do you plan to create a new SPARQL parser as part of Attean? I'd prefer to split SPARQL parsing and serialization from SPARQL execution. Thanks anyway!

[kasei]

Hi Jakob. Really sorry to hear this. I'll be committing a fix for this, but can appreciate that you've been finding quite a few bugs, and am sorry about that.

I've actually been working on a new SPARQL parser for Attean in the last few days, but a few thoughts I think are relevant:

• Most of the bugs you've been running into have been serialization bugs and don't have anything to do with the parser. The SPARQL serialization code hasn't ever been used much, and I suspect you're the only one doing anything serious with it.
• As mentioned in your wdq issue, I'd love to see a Marpa parser for SPARQL. However, be aware that none of the parsing bugs have had anything to do with the parser being hand-written vs. using something like Marpa. They've all been bugs in the code that is translating the AST into SPARQL algebra. You might have better luck doing that on top of Marpa, but simply changing parsing technology won't directly address the problem.

Let me know if I can be of any further help.

best, .greg

[nichtich]

Thanks for fixing, you were right this was a serializing issue. Anyway, could you please release a new version of RDF::Query including this fix?

[kasei]

Sure. I've uploaded a beta of RDF::Query 2.917 to CPAN, and will release a full version as soon as I see successful reports from cpan-testers.