Return unsubscribe function from SettingsDict.subscribe (#47)

Author: FichteFoll

st3/sublime_lib/settings_dict.py

@@ -2,6 +2,7 @@
 
 from uuid import uuid4
 from collections.abc import Mapping
+from functools import partial
 
 from .collection_utils import projection
 
@@ -145,8 +146,9 @@ def update(self, other=[], **kwargs):
 
     def subscribe(self, selector, callback, default_value=None):
         """
-        Register a calback to be invoked when the a value derived from the
-        settings object changes.
+        Register a callback to be invoked when the a value derived from the
+        settings object changes. Returns a function that when invoked will
+        unregister the callback.
 
         The derived value depends on the type of `selector`:
 
@@ -181,10 +183,7 @@ def onchange():
 
         key = str(uuid4())
         self.settings.add_on_change(key, onchange)
-        return key
-
-    def unsubscribe(self, key):
-        self.settings.clear_on_change(key)
+        return partial(self.settings.clear_on_change, key)
 
 
 class NamedSettingsDict(SettingsDict):

tests/test_settings_dict.py

@@ -140,9 +140,6 @@ def tearDown(self):
             self.view.window().focus_view(self.view)
             self.view.window().run_command("close_file")
 
-        if self.fancy and getattr(self, 'key', None):
-            self.fancy.unsubscribe(self.key)
-
     def test_subscribe(self):
         self.fancy['example_setting'] = 1
 
@@ -152,12 +149,12 @@ def callback(new, old):
             nonlocal values
             values = (new, old)
 
-        self.key = self.fancy.subscribe('example_setting', callback)
+        unsubscribe = self.fancy.subscribe('example_setting', callback)
 
         self.fancy['example_setting'] = 2
         self.assertEqual(values, (2, 1))
 
-        self.fancy.unsubscribe(self.key)
+        unsubscribe()
         self.fancy['example_setting'] = 3
         self.assertEqual(values, (2, 1))
 
@@ -173,7 +170,7 @@ def callback(new, old):
             nonlocal values
             values = new
 
-        self.key = self.fancy.subscribe({'example_1', 'example_2', 'example_3'}, callback)
+        self.fancy.subscribe({'example_1', 'example_2', 'example_3'}, callback)
 
         self.fancy['example_1'] = 10