Flesh out abstract base mixins (#17)

pottery/base.py

@@ -144,6 +144,10 @@ class _Clearable(metaclass=abc.ABCMeta):
     def redis(self):
         'Redis client.'
 
+    @abc.abstractproperty
+    def key(self):
+        'Redis key.'
+
     def clear(self):
         'Remove the elements in a Redis-backed container.  O(n)'
         self.redis.delete(self.key)
@@ -155,11 +159,16 @@ class _ContextManaged(metaclass=abc.ABCMeta):
     def redis(self):
         'Redis client.'
 
+    @abc.abstractmethod
+    def __del__(self):
+        ...
+
     def __enter__(self):
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
-        self.__del__()
+        self.__del__()  # We can't do del self because we still need a
+                        # referense to self for the next line...
         self.redis.connection_pool.disconnect()
 
 
@@ -170,6 +179,14 @@ class Base(_Common, _ContextManaged, _Clearable, Pipelined):
 
 
 class Iterable(metaclass=abc.ABCMeta):
+    @abc.abstractmethod
+    def _decode(value):
+        ...
+
+    @abc.abstractproperty
+    def key(self):
+        'Redis key.'
+
     @abc.abstractmethod
     def _scan(self, key, *, cursor=0):
         ...

pottery/dict.py

@@ -18,7 +18,7 @@
 
 
 
-class RedisDict(Iterable, Base, collections.abc.MutableMapping):
+class RedisDict(Base, Iterable, collections.abc.MutableMapping):
     'Redis-backed container compatible with Python dicts.'
 
     def __init__(self, iterable=tuple(), *, redis=None, key=None, **kwargs):

pottery/set.py

@@ -16,7 +16,7 @@
 
 
 
-class RedisSet(Iterable, Base, collections.abc.MutableSet):
+class RedisSet(Base, Iterable, collections.abc.MutableSet):
     'Redis-backed container compatible with Python sets.'
 
     def __init__(self, iterable=tuple(), *, redis=None, key=None):