On 11/22/06, Mikael Högqvist <[EMAIL PROTECTED]> wrote: > Implementing the evaluation algorithm from [1] using the intermediary > format for graph pattern expressions produced by the bison SPARQL > parser would probably result in cleaner code since many lines in > SPARQLEvaluate.py are used to prepare the input to sparql.queryObject.
Yes, this thought had crossed my mind many times and I think this is what I plan to try ultimately (which will mean doing away with sparql-p). > I did some simple attempts in that direction (not using the algorithm > in [1] though) a couple of months ago because I wanted to understand > the details of how SPARQL queries are evaluated. Rewriting has the > downside that a lot of the existing and tested code in rdflib.sparql > would go unused... I'd be interested in synchronizing with the attempts you have made. > Since the spec. is changing I think it is more important that it is > known exactly what the rdflib parser and evaluator supports. If I as a > user want to use rdflib, what can I expect? Related to this are the > tests running against the RDF DAWG data set, is the list with > commented out tests in test/BisonSPARQLParser/test.py up-to-date? Yes the list is up to date. BTW with regards to the changing spec, I found out today that a SPARQL algebra is being formulated [1] and looks so far like a good starting point for such a rewrite. It's based on the SPARQL complexity paper > > I'm currently using rdflib within a project and would be interested > spending time on the SPARQL query evaluation implementation. Please, > let me know how I can contribute? Well you could help me sketch an attempted implementation of [1] that uses the bison parsed objects to start with =). In fact most of the directives in that document are already being done by SPARQLEvaluate.py - it just needs to be broken away from the sparql-p core. Perhaps some initial unit tests and a development branch? [1] http://www.w3.org/2001/sw/DataAccess/rq23/rq24-algebra.html _______________________________________________ Dev mailing list Dev@rdflib.net http://rdflib.net/mailman/listinfo/dev
