Approaching release

twinql is getting there… the parser now generates correct expressions for even complex queries (nonsense though they may be):

* (parse-sparql 
  "PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
  SELECT ?name ?mbox WHERE { 
    ?x foaf:name ?name .  
    ?x foaf:mbox ?mbox .
    ?y foaf:knows ?knows .
    foaf:knows rdfs:label ?label .
  OPTIONAL {
    ?x a ?what .
    ?y a ?something .
    {} .
    { ?y a ?nested . } .
    OPTIONAL { 
      ?x ?something ?z .
      FILTER ( ?z < 5) .
    } .
  } .
  { ?something a ?flarp . }}")
(SPARQL 
  :SELECT
  :VARS (|name| |mbox|)
  :WHERE
  '(GRAPH-PATTERN 
     (TRIPLE |x| !foaf:name |name|)
     (TRIPLE |x| !foaf:mbox |mbox|)
     (TRIPLE |y| !foaf:knows |knows|)
     (TRIPLE "foaf:knows" !"rdfs:label" |label|)
     (OPTIONAL
       (GRAPH-PATTERN 
         (TRIPLE |x| !rdf:type |what|)
         (TRIPLE |y| !rdf:type |something|)
         (GRAPH-PATTERN)
         (GRAPH-PATTERN
            (TRIPLE |y| !rdf:type |nested|))
         (OPTIONAL
           (GRAPH-PATTERN
             (TRIPLE |x| |something| |y|)
             (FILTER (< |x| 5))))))
     (GRAPH-PATTERN 
       (TRIPLE |something| !rdf:type |flarp|))))

It also runs nested graph patterns, optionals, unions (not thoroughly tested), and so on, and I'm part-way through implementing filters. Ah yes, filters — complex buggers to do right.

I'm very pleased that this works:

(run-sparql 
"PREFIX foaf: <http://xmlns.com/foaf/0.1/> 
 SELECT ?name ?mbox WHERE { 
   ?x foaf:name ?name . 
   OPTIONAL { 
     ?x foaf:mbox ?mbox .
   } . 
 }" :stream *standard-output*
    :result-format :sparql-xml)

To parse, compile, and run that query on my FOAF file (780-odd statements) takes about 110ms. Not bad.

Release date… soon.

Posted at 2005-06-29 09:43:09 by Richard • Link to Approaching releas…
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