Working on RDFLib#955 Success enough for today, basic examples pass

Approach is horrid though, and code is being executed in the wrong place.

rdflib/plugins/sparql/algebra.py

@@ -16,6 +16,8 @@
 
 from rdflib import Literal, Variable, URIRef, BNode
 
+from rdflib.namespace import RDF
+
 from rdflib.plugins.sparql.sparql import Prologue, Query
 from rdflib.plugins.sparql.parserutils import CompValue, Expr
 from rdflib.plugins.sparql.operators import (
@@ -243,6 +245,46 @@ def collectAndRemoveFilters(parts):
 
     return None
 
+def collectExpandEmpTP(parts):
+    """
+
+    FILTER expressions apply to the whole group graph pattern in which
+    they appear.
+
+    http://www.w3.org/TR/sparql11-query/#sparqlCollectFilters
+    """
+
+
+
+    i = 0
+    while i < len(parts):
+        p = parts[i]
+        if p.name == 'TriplesBlock':
+            newTriples = []
+            for t in p.triples:
+                if isinstance(t[0], CompValue) and t[0].name == 'EmpTP':
+                    r = Variable('__EMP_s_'+ str(i))
+                    e = t[0]
+                    t[0] = r
+                    newTriples.append([e.s[0], e.p[0], e.o[0]])
+                    t.extend([r, RDF.type, RDF.Statement,
+                                       r, RDF.subject, e.s[0],
+                                       r, RDF.predicate, e.p[0],
+                                       r, RDF.object, e.o[0]])
+                if isinstance(t[2], CompValue) and t[2].name == 'EmpTP':
+                    r = Variable('__EMP_o_'+str(i))
+                    e = t[2]
+                    t[2] = r
+                    newTriples.append([e.s[0], e.p[0], e.o[0]])
+                    newTriples.append([r, RDF.type, RDF.Statement,
+                                       r, RDF.subject, e.s[0],
+                                       r, RDF.predicate, e.p[0],
+                                       r, RDF.object, e.o[0]])
+            for t in newTriples:
+                p.triples.append(t)
+        i += 1
+
+    return parts
 
 def translateGroupOrUnionGraphPattern(graphPattern):
     A = None
@@ -278,6 +320,7 @@ def translateGroupGraphPattern(graphPattern):
 
     filters = collectAndRemoveFilters(graphPattern.part)
 
+    graphPattern.part = collectExpandEmpTP(graphPattern.part)
     g = []
     for p in graphPattern.part:
         if p.name == 'TriplesBlock':
@@ -346,11 +389,9 @@ def _traverse(e, visitPre=lambda n: None, visitPost=lambda n: None):
         return tuple([_traverse(x, visitPre, visitPost) for x in e])
 
     elif isinstance(e, CompValue):
-        if e.name != 'EmpTP':
-            for k, val in e.items():
-                e[k] = _traverse(val, visitPre, visitPost)
-        else:
-            raise Exception("Sparql star not tied into the algebra jet")
+        for k, val in e.items():
+            e[k] = _traverse(val, visitPre, visitPost)
+
     _e = visitPost(e)
     if _e is not None:
         return _e

rdflib/plugins/sparql/parser.py

@@ -24,7 +24,7 @@
 
 import rdflib
 
-DEBUG = True
+DEBUG = False
 
 # ---------------- ACTIONS
 

test/test_sparql_star.py

@@ -1,40 +1,122 @@
 from rdflib import Graph
-from rdflib.plugins.sparql.parser import VarOrBlankNodeOrIriOrLitOrEmbTP
-import  pyparsing
+from rdflib.namespace import RDF, Namespace
 import unittest
 
+
+
 class SparqlStarTests(unittest.TestCase):
 
-    @staticmethod
-    def test_basic_sparql_star_subject():
+    def test_basic_sparql_star_subject(self):
         g = Graph()
-        res = g.query('''SELECT * WHERE {
-    << ?s ?p ?o >> ?p2 ?o2 . 
-    }''')
+        g.parse(data="""
+        PREFIX ex:<http://example.org/>
+        PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+        
+        ex:subject ex:predicate ex:object .
+        ex:reif a rdf:Statement ;
+         rdf:subject ex:subject ;
+         rdf:predicate ex:predicate ;
+         rdf:object ex:object .
+        ex:about a ex:reif .
+        """, format="ttl")
+        res = g.query('''SELECT * WHERE {<< ?s ?p ?o >> ?p2 ?o2 . }''')
 
-    @staticmethod
-    def test_basic_sparql_star_object():
+        rl = list(res)
+        self.assertEqual(4 , len(rl))
+
+
+    def test_basic_sparql_star_object(self):
         g = Graph()
+        g.parse(data="""
+        PREFIX ex:<http://example.org/>
+        PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+        
+        ex:subject ex:predicate ex:object .
+        ex:reif a rdf:Statement ;
+         rdf:subject ex:subject ;
+         rdf:predicate ex:predicate ;
+         rdf:object ex:object .
+        ex:about a ex:reif .
+        """, format="ttl")
         res = g.query('''SELECT * WHERE {
     ?s ?p << ?s2 ?p2 ?o2 >> . 
     }''')
+        rl = list(res)
+        self.assertEqual(1 , len(rl))
 
-    @staticmethod
-    def test_basic_sparql():
+
+    def test_basic_sparql(self):
         g = Graph()
-        res = g.query('''SELECT * WHERE {
+        g.parse(data="""
+        PREFIX ex:<http://example.org/>
+        PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+
+        ex:subject ex:predicate ex:object .
+        ex:reif a rdf:Statement ;
+         rdf:subject ex:subject ;
+         rdf:predicate ex:predicate ;
+         rdf:object ex:object .
+     ex:about a ex:reif .
+        """, format="ttl")
+        res = g.query('''PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
+        SELECT * WHERE {
         ?s ?p ?o . 
+        ?r a rdf:Statement ;
+           rdf:subject ?s ;
+           rdf:predicate ?p ;
+           rdf:object ?o .
+        ex:about a ?r.
         }''')
+        rl = list(res)
+        self.assertEqual(1 , len(rl))
 
     @staticmethod
     def test_bind_sparql_star():
         g = Graph()
         res = g.query('''SELECT * WHERE { BIND(<< ?s2 ?p2 ?o2 >> AS ?b) }''')
 
-    @staticmethod
-    def test_parser():
-        assert VarOrBlankNodeOrIriOrLitOrEmbTP.matches("<<?s ?p ?o>>")
+    def test_constant_sparql_star_object(self):
+        g = Graph()
+        g.parse(data="""
+           PREFIX ex:<http://example.org/>
+           PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
 
+           ex:subject ex:predicate ex:object .
+           ex:reif a rdf:Statement ;
+            rdf:subject ex:subject ;
+            rdf:predicate ex:predicate ;
+            rdf:object ex:object .
+           ex:reif a ex:about .
+           """, format="ttl")
+        res = g.query('''PREFIX ex:<http://example.org/> SELECT * WHERE {
+        << ex:subject ex:predicate ?object >> a ex:about  . 
+        }''')
+        rl = list(res)
+        self.assertEqual(1 , len(rl))
+
+    def test_constant_sparql_object(self):
+        g = Graph()
+        g.parse(data="""
+           PREFIX ex:<http://example.org/>
+           PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>
 
+           ex:subject ex:predicate ex:object .
+           ex:reif a rdf:Statement ;
+            a ex:about ;
+            rdf:subject ex:subject ;
+            rdf:predicate ex:predicate ;
+            rdf:object ex:object .
+           
+           """, format="ttl")
+        res = g.query('''PREFIX ex:<http://example.org/> SELECT * WHERE {
+        ex:subject ex:predicate ?object .
+        ex:reif a ex:about  ;
+        a rdf:Statement ;
+        rdf:subject ex:subject ;
+        rdf:predicate ex:predicate ;
+        rdf:object ?object . 
+        }''')
+        rl = list(res)
+        self.assertEqual(1 , len(rl))
 if __name__ == '__main__':
     unittest.main()