Is RDQL Supported?

[ThomasThelen]

In Jena 2, RDQL was supported. Is it still possible to run RDQL queries from Jena?

[rvesse]

No, it was a non-standard language superseded by the SPARQL language standards.

Is there some specific functionality of RDQL you need?

Most likely anything you could have done with RDQL can be done with SPARQL

[ThomasThelen]

I'm part of the RDQL revivalist movement (emphasis on KRSL, L-ONE, KQML, etc). I guess Jena has gone too mainstream now

[afs]

The functionality of RDQL is SPARQL BGP+FILTER.

It would only take writing parser that generates a parse tree made of SPARQL syntax elements put into a (current) Query object, then pass that Query to the SPARQL execution engine and you have an implementation of RDQL.

The original RDQL grammar is in old versions of Jena (pre-Apache, well it's somewhere in the SVN tree but hard to find). The parser generated complete in-memory abstract syntax tree (needed for USING...FOR). It uses JavaCC (jjtree) to get an AST.

The file is called rdql-arq.jjt.
rdql-arq.jjt.txt
The file timestamp is Sept 2007 but it looks to be the 2004 version.
Original license BSD 3-clause -- this copy is covered by the Software Grant to Apache (I dug the file out of a copy of the Apache import).

[afs]

For completeness: BRQL, an intermediate between RDQL and SPARQL.

brql-rdql.jjt.txt