Add 30+ SPARQL 1.1 built-in functions and the MINUS algebra operator to the
custom SPARQL query backend.
String functions:
- SUBSTR (2-arg and 3-arg forms), STRBEFORE, STRAFTER
- REPLACE (regex with flags), ENCODE_FOR_URI
Numeric functions:
- FLOOR, CEIL, ROUND, ABS
Date/time accessors:
- YEAR, MONTH, DAY, HOURS, MINUTES, SECONDS
- NOW, TZ
Hash functions:
- MD5, SHA1, SHA256, SHA512
Term constructors:
- IRI/URI, BNODE, UUID, STRUUID
Other functions:
- LANGMATCHES, RAND
- EXISTS / NOT EXISTS (with async pre-evaluation to bridge the
sync expression evaluator and async algebra evaluator)
Algebra:
- MINUS set-difference operator
- HAVING already works via rdflib's Filter mapping (verified)
Fix SPARQL ORDER handling
Includes 653 lines of new unit tests covering all added functionality
across expressions, solutions, and algebra layers.
Fix threading of workspace paramater:
- The SPARQL algebra evaluator was threading a workspace parameter
through every function and passing it to TriplesClient.query(),
which doesn't accept it. Workspace isolation is handled by pub/sub
topic routing — the TriplesClient is already scoped to a
workspace-specific flow, same as GraphRAG. Passing workspace
explicitly was both incorrect and unnecessary.
Update tests:
- tests/unit/test_query/test_sparql_algebra.py (new) — Tests
_query_pattern, _eval_bgp, and evaluate() with various algebra
nodes. Key tests assert workspace is never in tc.query() kwargs,
plus correctness tests for BGP, JOIN, UNION, SLICE, DISTINCT, and
edge cases.
- tests/unit/test_retrieval/test_graph_rag.py — Added
test_triples_query_never_passes_workspace (checks query()) and
test_follow_edges_never_passes_workspace (checks query_stream()).
