Source code of RDF-3X can be obtained from RDF-3X Google Code Repository.

A summary of SPARQL support of RDF-3X based on my own testing.

Query Types

</tr> </tr> </tbody> </table> **Projection**
Query Type Example Support
SELECT SELECT ?a WHERE{?a "Jeff"}</td> Yes
ASK ASK ?a WHERE{?a "Jeff"}</td> No
DESCRIBE DESCRIBE <http://www.facebook.com/johndoe> No
CONSTRUCT No
</tr> </tr> </tr> </tr> </tbody> </table> **Graph Pattern**
Feature Example Support
DISTINCT SELECT DISTINCT ?a WHERE{?a "Jeff"}</td> Yes
Expressions SELECT (1+1) No
LIMIT SELECT ?url WHERE{?url "Jeff"} LIMIT 10</td> Yes
OFFSET SELECT ?url WHERE{?url "Jeff"} OFFSET 10</td> No
ORDER BY SELECT ?url ?age WHERE{?url "Jeff". ?url ?age} ORDER BY ?age</td> Yes
</tr> </tbody> </table>
Feature Example Support
UNION SELECT ?name
WHERE {?e ?name. {?e "actor"} UNION {?e "athlete"}}</td>
Yes