Give the nearest-neighbour cursors classes of their own

docs/object-model.md

@@ -125,7 +125,8 @@ that set from the two predicates and fails until each has a class, so a
 base type MEOS adds reaches the model with no edit to the file.
 `Nsegment`, `Raquet` and `JsonPath` are the MeosTypes no membership
 predicate admits; the model states them, and the same gate states that it
-does. `Pcschema`, `RTree`, `SPTree` and `MeosArray` go further: MEOS
+does. `Pcschema`, `RTree`, `RTreeNNCursor`, `SPTree`, `SPNNCursor` and
+`MeosArray` go further: MEOS
 registers them in no enum at all, and they say so with a null `temptype`
 rather than by leaving the field out. To a binding a pointer to a struct
 is one thing — an instance it holds and calls through — whether MEOS

meta/object-model.json

@@ -726,6 +726,15 @@
           "temptype": null,
           "doc": "MEOS's in-memory R-tree over spans, boxes and their kin. MEOS registers it in no enum, so it names no temptype."
         },
+        "RTreeNNCursor": {
+          "kind": "leaf",
+          "parent": "Value",
+          "prefixes": [
+            "rtree_nn_cursor"
+          ],
+          "temptype": null,
+          "doc": "A walk over an R-tree's entries in order of distance from a query. MEOS registers it in no enum, so it names no temptype."
+        },
         "SPTree": {
           "kind": "leaf",
           "parent": "Value",
@@ -735,6 +744,15 @@
           "temptype": null,
           "doc": "MEOS's in-memory SP-tree, the R-tree's sibling over the same key types. MEOS registers it in no enum, so it names no temptype."
         },
+        "SPNNCursor": {
+          "kind": "leaf",
+          "parent": "Value",
+          "prefixes": [
+            "sptree_nn_cursor"
+          ],
+          "temptype": null,
+          "doc": "The SP-tree's nearest-neighbour walk, the R-tree cursor's sibling. MEOS registers it in no enum, so it names no temptype."
+        },
         "MeosArray": {
           "kind": "leaf",
           "parent": "Value",

tests/test_object_model.py

@@ -241,7 +241,8 @@ def test_a_type_meos_registers_in_no_enum_still_gets_a_class(self):
         unregistered = {n for n, s in nodes.items()
                         if s["kind"] == "leaf" and s["temptype"] is None}
         self.assertEqual(unregistered,
-                         {"Pcschema", "RTree", "SPTree", "MeosArray"})
+                         {"Pcschema", "RTree", "RTreeNNCursor", "SPTree",
+                          "SPNNCursor", "MeosArray"})
 
     def test_a_function_named_as_its_own_prefix_still_has_a_member_name(self):
         # `meos_pc_schema` IS its class's prefix, so dropping the prefix leaves