trie: introduce delete_node

src/sqltrie/pygtrie.py

@@ -51,6 +51,9 @@ def __len__(self):
     def has_node(self, key):
         return bool(self._trie.has_node(key))
 
+    def delete_node(self, key):
+        raise NotImplementedError
+
     def items(self, prefix=None, shallow=False):
         kwargs = {"shallow": shallow}
         if prefix is not None:

src/sqltrie/serialized.py

@@ -99,6 +99,9 @@ def diff(self, *args, **kwargs):
     def has_node(self, key):
         return self._trie.has_node(key)
 
+    def delete_node(self, key):
+        return self._trie.delete_node(key)
+
     def shortest_prefix(self, key):
         sprefix = self._trie.shortest_prefix(key)
         if sprefix is None:

src/sqltrie/sqlite/sqlite.py

@@ -149,16 +149,6 @@ def _get_children(self, key, limit=None):
             (node["id"],),
         ).fetchall()
 
-    def _delete_node(self, key):
-        node = self._get_node(key)
-        del self._ids[key]
-        self._conn.execute(
-            """
-            DELETE FROM nodes WHERE id = ?
-            """,
-            (node["id"],),
-        )
-
     def __setitem__(self, key, value):
         pid = self._create_node(key[:-1])
 
@@ -290,6 +280,16 @@ def has_node(self, key: TrieKey) -> bool:
         except KeyError:
             return False
 
+    def delete_node(self, key: TrieKey):
+        node = self._get_node(key)
+        del self._ids[key]
+        self._conn.execute(
+            """
+            DELETE FROM nodes WHERE id = ?
+            """,
+            (node["id"],),
+        )
+
     def ls(
         self, key: TrieKey, with_values: Optional[bool] = False
     ) -> Iterator[Union[TrieKey, TrieNode]]:

src/sqltrie/trie.py

@@ -85,6 +85,11 @@ def view(self, key: Optional[TrieKey] = None) -> "AbstractTrie":
     def has_node(self, key: TrieKey) -> bool:
         pass
 
+    @abstractmethod
+    def delete_node(self, key: TrieKey) -> bool:
+        # NOTE: this will leave orphans down the tree
+        pass
+
     @abstractmethod
     def prefixes(self, key: TrieKey) -> Iterator[TrieStep]:
         pass