Update callable provider docs, including API, and examples

dependency_injector/providers.py

@@ -293,7 +293,18 @@ class Singleton(Provider):
     __slots__ = ('instance', 'factory')
 
     def __init__(self, provides, *args, **kwargs):
-        """Initializer."""
+        """Initializer.
+
+        :param provides: Class or other callable that provides object
+            for creation.
+        :type provides: type | callable
+
+        :param args: Tuple of injections.
+        :type args: tuple
+
+        :param kwargs: Dictionary of injections.
+        :type kwargs: dict
+        """
         self.instance = None
         """Read-only reference to singleton's instance.
 
@@ -492,33 +503,78 @@ class Value(StaticProvider):
 
 
 class Callable(Provider):
-    """Callable provider.
+    """:py:class:`Callable` provider calls wrapped callable on every call.
 
-    Callable provider provides callable that is called on every provider call
-    with some predefined dependency injections.
+    :py:class:`Callable` provider provides callable that is called on every
+    provider call with some predefined dependency injections.
+
+    :py:class:`Callable` syntax of passing injections is the same like
+    :py:class:`Factory` one:
+
+    .. code-block:: python
+
+        some_function = Callable(some_function, 'arg1', 'arg2', arg3=3, arg4=4)
+        result = some_function()
     """
 
     __slots__ = ('callback', 'args', 'kwargs')
 
     def __init__(self, callback, *args, **kwargs):
-        """Initializer."""
+        """Initializer.
+
+        :param callback: wrapped callable.
+        :type callback: callable
+
+        :param args: Tuple of injections.
+        :type args: tuple
+
+        :param kwargs: Dictionary of injections.
+        :type kwargs: dict
+        """
         if not callable(callback):
             raise Error('Callable expected, got {0}'.format(str(callback)))
         self.callback = callback
-        self.args = _parse_args_injections(args)
-        self.kwargs = _parse_kwargs_injections(args, kwargs)
-        super(Callable, self).__init__()
+        """Wrapped callable.
 
-    def _provide(self, *args, **kwargs):
-        """Return provided instance."""
-        return self.callback(*_get_injectable_args(args, self.args),
-                             **_get_injectable_kwargs(kwargs, self.kwargs))
+        :type: callable
+        """
+
+        self.args = _parse_args_injections(args)
+        """Tuple of positional argument injections.
+
+        :type: tuple[:py:class:`dependency_injector.injections.Arg`]
+        """
+
+        self.kwargs = _parse_kwargs_injections(args, kwargs)
+        """Tuple of keyword argument injections.
+
+        :type: tuple[:py:class:`dependency_injector.injections.KwArg`]
+        """
+
+        super(Callable, self).__init__()
 
     @property
     def injections(self):
-        """Return tuple of all injections."""
+        """Read-only tuple of all injections.
+
+        :rtype: tuple[:py:class:`dependency_injector.injections.Injection`]
+        """
         return self.args + self.kwargs
 
+    def _provide(self, *args, **kwargs):
+        """Return provided instance.
+
+        :param args: tuple of context positional arguments
+        :type args: tuple[object]
+
+        :param kwargs: dictionary of context keyword arguments
+        :type kwargs: dict[str, object]
+
+        :rtype: object
+        """
+        return self.callback(*_get_injectable_args(args, self.args),
+                             **_get_injectable_kwargs(kwargs, self.kwargs))
+
 
 class Config(Provider):
     """Config provider.

docs/providers/callable.rst

@@ -1,40 +1,43 @@
 Callable providers
 ------------------
 
-``di.Callable`` provider is a provider that wraps particular callable with
+.. module:: dependency_injector.providers
+
+:py:class:`Callable` provider is a provider that wraps particular callable with
 some injections. Every call of this provider returns result of call of initial
 callable.
 
 Callable providers and injections
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-``di.Callable`` takes a various number of positional and keyword arguments 
-that are used as decorated callable injections. Every time, when 
-``di.Callable`` is called, positional and keyword argument injections would be 
-passed as an callable arguments.
+:py:class:`Callable` takes a various number of positional and keyword 
+arguments that are used as decorated callable injections. Every time, when 
+:py:class:`Callable` is called, positional and keyword argument injections 
+would be passed as an callable arguments.
 
 Such behaviour is very similar to the standard Python ``functools.partial`` 
 object, except of one thing: all injectable values are provided 
-*"as is"*, except of providers (subclasses of ``di.Provider``). Providers 
+*"as is"*, except of providers (subclasses of :py:class:`Provider`). Providers 
 will be called every time, when injection needs to be done. For example, 
-if injectable value of injection is a ``di.Factory``, it will provide new one 
-instance (as a result of its call) every time, when injection needs to be done.
+if injectable value of injection is a :py:class:`Factory`, it will provide 
+new one instance (as a result of its call) every time, when injection needs 
+to be done.
 
-``di.Callable`` behaviour with context positional and keyword arguments is 
-very like a standard Python ``functools.partial``:
+:py:class:`Callable` behaviour with context positional and keyword arguments 
+is very like a standard Python ``functools.partial``:
 
-- Positional context arguments will be appended after ``di.Callable`` 
+- Positional context arguments will be appended after :py:class:`Callable` 
   positional injections.
-- Keyword context arguments have priority on ``di.Callable`` keyword 
+- Keyword context arguments have priority on :py:class:`Callable` keyword 
   injections and will be merged over them.
 
-Example that shows usage of ``di.Callable`` with positional argument 
+Example that shows usage of :py:class:`Callable` with positional argument 
 injections:
 
 .. literalinclude:: ../../examples/providers/callable_args.py
    :language: python
 
-Next one example shows usage of ``di.Callable`` with keyword argument 
+Next one example shows usage of :py:class:`Callable` with keyword argument 
 injections:
 
 .. image:: /images/providers/callable.png
@@ -47,13 +50,13 @@ injections:
 Callable providers delegation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-``di.Callable`` provider could be delegated to any other provider via any kind 
-of injection. Delegation of ``di.Callable`` providers is the same as 
-``di.Factory`` and ``di.Singleton`` providers delegation, please follow 
-*Factory providers delegation* section for example.
+:py:class:`Callable` provider could be delegated to any other provider via any 
+kind of injection. Delegation of :py:class:`Callable` providers is the same as 
+:py:class:`Factory` and :py:class:`Singleton` providers delegation, please 
+follow *Factory providers delegation* section for example.
 
-``di.Callable`` delegate could be created obviously using 
-``di.Delegate(di.Callable())`` or by calling ``di.Callable.delegate()`` method.
+:py:class:`Callable` delegate could be created obviously using 
+``Delegate(Callable(...))`` or by calling ``Callable(...).delegate()`` method.
 
 Example:
 

examples/providers/callable_args.py

@@ -1,11 +1,11 @@
-"""`di.Callable` providers with positional arguments example."""
+"""`Callable` providers with positional arguments example."""
 
-import dependency_injector as di
+from dependency_injector import providers
 
 
 # Creating even and odd filter providers:
-even_filter = di.Callable(filter, lambda x: x % 2 == 0)
-odd_filter = di.Callable(filter, lambda x: x % 2 != 0)
+even_filter = providers.Callable(filter, lambda x: x % 2 == 0)
+odd_filter = providers.Callable(filter, lambda x: x % 2 != 0)
 
 # Creating even and odd ranges using xrange() and filter providers:
 even_range = even_filter(xrange(1, 10))

examples/providers/callable_delegation.py

@@ -1,13 +1,14 @@
-"""`di.Callable` providers delegation example."""
+"""`Callable` providers delegation example."""
 
 import sys
-import dependency_injector as di
+
+from dependency_injector import providers
 
 
 # Creating some callable provider and few delegates of it:
-callable_provider = di.Callable(sys.exit)
+callable_provider = providers.Callable(sys.exit)
 callable_provider_delegate1 = callable_provider.delegate()
-callable_provider_delegate2 = di.Delegate(callable_provider)
+callable_provider_delegate2 = providers.Delegate(callable_provider)
 
 # Making some asserts:
 assert callable_provider_delegate1() is callable_provider

examples/providers/callable_kwargs.py

@@ -1,14 +1,16 @@
-"""`di.Callable` providers with keyword arguments example."""
+"""`Callable` providers with keyword arguments example."""
 
 import passlib.hash
-import dependency_injector as di
+
+from dependency_injector import providers
+
 
 # Password hasher and verifier providers (hash function could be changed
 # anytime (for example, to sha512) without any changes in client's code):
-password_hasher = di.Callable(passlib.hash.sha256_crypt.encrypt,
+password_hasher = providers.Callable(passlib.hash.sha256_crypt.encrypt,
                                      salt_size=16,
                                      rounds=10000)
-password_verifier = di.Callable(passlib.hash.sha256_crypt.verify)
+password_verifier = providers.Callable(passlib.hash.sha256_crypt.verify)
 
 # Making some asserts:
 hashed_password = password_hasher('super secret')