Add path groups (#37)

* Add path groups #26, #35

* Remove unnecessary enumerate

* Update CHANGELOG and bump version in setup.py

CHANGELOG.md

@@ -1,6 +1,14 @@
 # CHANGELOG
 
-### **0.5.0** (Unreleased)
+### **0.6.0** (February 15 2024)
+
+> New path group operator
+
+#### Features
+
+-   Support for path group operators (#37)
+
+### **0.5.0** (February 13 2024)
 
 > Lots of language support for new query operators.
 

grandcypher/__init__.py

@@ -46,7 +46,9 @@
 many_match_clause   : (match_clause)+
 
 
-match_clause        : "match"i node_match (edge_match node_match)*
+match_clause        : "match"i path_clause? node_match (edge_match node_match)*
+
+path_clause         : CNAME EQUAL
 
 where_clause        : "where"i compound_condition
 
@@ -111,6 +113,7 @@
 
 LEFT_ANGLE          : "<"
 RIGHT_ANGLE         : ">"
+EQUAL               : "="
 MIN_HOP             : INT
 MAX_HOP             : INT
 TYPE                : CNAME
@@ -309,6 +312,7 @@ def _data_path_to_entity_name_attribute(data_path):
 class _GrandCypherTransformer(Transformer):
     def __init__(self, target_graph: nx.Graph, limit=None):
         self._target_graph = target_graph
+        self._paths = []
         self._where_condition: CONDITION = None
         self._motif = nx.DiGraph()
         self._matches = None
@@ -327,7 +331,7 @@ def _lookup(self, data_paths: List[str], offset_limit) -> Dict[str, List]:
 
         for data_path in data_paths:
             entity_name, _ = _data_path_to_entity_name_attribute(data_path)
-            if entity_name not in motif_nodes and entity_name not in self._return_edges:
+            if entity_name not in motif_nodes and entity_name not in self._return_edges and entity_name not in self._paths:
                 raise NotImplementedError(f"Unknown entity name: {data_path}")
 
         result = {}
@@ -352,6 +356,20 @@ def _lookup(self, data_paths: List[str], offset_limit) -> Dict[str, List]:
                         for node in ret
                     )
 
+            elif entity_name in self._paths:
+                ret = []
+                for mapping, _ in true_matches:
+                    path, nodes = [], list(mapping.values())
+                    for x, node in enumerate(nodes):
+                        # Edge
+                        if x > 0:
+                            path.append(self._target_graph.get_edge_data(nodes[x - 1], node))
+
+                        # Node
+                        path.append(node)
+
+                    ret.append(path)
+
             else:
                 mapping_u, mapping_v = self._return_edges[data_path]
                 # We are looking for an edge mapping in the target graph:
@@ -460,8 +478,7 @@ def _matches_iter(self, motif):
 
         # Single match clause iterator
         if iterators and len(iterators) == 1:
-            for x, match in enumerate(iterators[0]):
-                yield match
+            yield from iterators[0]
 
         # Multi match clause, requires a cartesian join
         else:
@@ -603,6 +620,8 @@ def match_clause(self, match_clause: Tuple):
             u, ut, js = match_clause[0]
             self._motif.add_node(u.value, __labels__=ut, **js)
             return
+
+        match_clause = match_clause[1:] if not match_clause[0] else match_clause
         for start in range(0, len(match_clause) - 2, 2):
             ((u, ut, ujs), (g, t, d, minh, maxh), (v, vt, vjs)) = match_clause[
                 start : start + 3
@@ -633,6 +652,9 @@ def match_clause(self, match_clause: Tuple):
             self._motif.add_node(u, __labels__=ut, **ujs)
             self._motif.add_node(v, __labels__=vt, **vjs)
 
+    def path_clause(self, path_clause: tuple):
+        self._paths.append(path_clause[0])
+
     def where_clause(self, where_clause: tuple):
         self._where_condition = where_clause[0]
 

grandcypher/test_queries.py

@@ -1157,3 +1157,23 @@ def test_nested_nots_in_statements(self):
 
         res = GrandCypher(host).run(qry)
         assert len(res["Instrument"]) == 1
+
+
+class TestPath:
+    def test_path(self):
+        host = nx.DiGraph()
+        host.add_node("x", name="x")
+        host.add_node("y", name="y")
+        host.add_node("z", name="z")
+
+        host.add_edge("x", "y", foo="bar")
+        host.add_edge("y", "z",)
+
+        qry = """
+        MATCH P = ()-[r*2]->()
+        RETURN P
+        LIMIT 1
+        """
+
+        res = GrandCypher(host).run(qry)
+        assert len(res["P"][0]) == 5

setup.py

@@ -5,7 +5,7 @@
 
 setuptools.setup(
     name="grand-cypher",
-    version="0.5.0",
+    version="0.6.0",
     author="Jordan Matelsky",
     author_email="opensource@matelsky.com",
     description="Query Grand graphs using Cypher",