If you make a SELECT or an ASK query, the response will be turned into a
EasyRdf_Sparql_Result object.
If you make a CONSTRUCT or DESCRIBE query, the response will be turned
into a EasyRdf_Graph object.
A SPARQL SELECT query is just a table of results, like the result of an
SQL query or a spreadsheet. There isn't a direct way of turning it back
into RDF. It doesn't look like you can just json_encode() a
EasyRdf_Sparql_Result object, but it probably wouldn't take very much code
to convert it to some simple JSON.
nick.