pythongh-101100: Improve documentation for attributes on instance methods (python#112832)

Author: AlexWaygood

Doc/library/inspect.rst

@@ -492,7 +492,7 @@ attributes (see :ref:`import-mod-attrs` for module attributes):
    Methods implemented via descriptors that also pass one of the other tests
    return ``False`` from the :func:`ismethoddescriptor` test, simply because the
    other tests promise more -- you can, e.g., count on having the
-   :ref:`__func__ <instance-methods>` attribute (etc) when an object passes
+   :attr:`~method.__func__` attribute (etc) when an object passes
    :func:`ismethod`.
 
 

Doc/library/stdtypes.rst

@@ -5328,25 +5328,30 @@ Methods
 .. index:: pair: object; method
 
 Methods are functions that are called using the attribute notation. There are
-two flavors: built-in methods (such as :meth:`append` on lists) and class
-instance methods.  Built-in methods are described with the types that support
-them.
+two flavors: :ref:`built-in methods <builtin-methods>` (such as :meth:`append`
+on lists) and :ref:`class instance method <instance-methods>`.
+Built-in methods are described with the types that support them.
 
 If you access a method (a function defined in a class namespace) through an
 instance, you get a special object: a :dfn:`bound method` (also called
-:dfn:`instance method`) object. When called, it will add the ``self`` argument
+:ref:`instance method <instance-methods>`) object. When called, it will add
+the ``self`` argument
 to the argument list.  Bound methods have two special read-only attributes:
-``m.__self__`` is the object on which the method operates, and ``m.__func__`` is
+:attr:`m.__self__ <method.__self__>` is the object on which the method
+operates, and :attr:`m.__func__ <method.__func__>` is
 the function implementing the method.  Calling ``m(arg-1, arg-2, ..., arg-n)``
 is completely equivalent to calling ``m.__func__(m.__self__, arg-1, arg-2, ...,
 arg-n)``.
 
-Like function objects, bound method objects support getting arbitrary
+Like :ref:`function objects <user-defined-funcs>`, bound method objects support
+getting arbitrary
 attributes.  However, since method attributes are actually stored on the
-underlying function object (``meth.__func__``), setting method attributes on
+underlying function object (:attr:`method.__func__`), setting method attributes on
 bound methods is disallowed.  Attempting to set an attribute on a method
 results in an :exc:`AttributeError` being raised.  In order to set a method
-attribute, you need to explicitly set it on the underlying function object::
+attribute, you need to explicitly set it on the underlying function object:
+
+.. doctest::
 
    >>> class C:
    ...     def method(self):
@@ -5361,7 +5366,7 @@ attribute, you need to explicitly set it on the underlying function object::
    >>> c.method.whoami
    'my name is method'
 
-See :ref:`types` for more information.
+See :ref:`instance-methods` for more information.
 
 
 .. index:: object; code, code object

Doc/reference/datamodel.rst

@@ -519,6 +519,8 @@ These are the types to which the function call operation (see section
 :ref:`calls`) can be applied:
 
 
+.. _user-defined-funcs:
+
 User-defined functions
 ^^^^^^^^^^^^^^^^^^^^^^
 
@@ -654,43 +656,64 @@ callable object (normally a user-defined function).
    single: __name__ (method attribute)
    single: __module__ (method attribute)
 
-Special read-only attributes: :attr:`__self__` is the class instance object,
-:attr:`__func__` is the function object; :attr:`__doc__` is the method's
-documentation (same as ``__func__.__doc__``); :attr:`~definition.__name__` is the
-method name (same as ``__func__.__name__``); :attr:`__module__` is the
-name of the module the method was defined in, or ``None`` if unavailable.
+Special read-only attributes:
+
+.. list-table::
+
+   * - .. attribute:: method.__self__
+     - Refers to the class instance object to which the method is
+       :ref:`bound <method-binding>`
+
+   * - .. attribute:: method.__func__
+     - Refers to the original function object
+
+   * - .. attribute:: method.__doc__
+     - The method's documentation (same as :attr:`!method.__func__.__doc__`).
+       A :class:`string <str>` if the original function had a docstring, else
+       ``None``.
+
+   * - .. attribute:: method.__name__
+     - The name of the method (same as :attr:`!method.__func__.__name__`)
+
+   * - .. attribute:: method.__module__
+     - The name of the module the method was defined in, or ``None`` if
+       unavailable.
 
 Methods also support accessing (but not setting) the arbitrary function
-attributes on the underlying function object.
+attributes on the underlying :ref:`function object <user-defined-funcs>`.
 
 User-defined method objects may be created when getting an attribute of a
 class (perhaps via an instance of that class), if that attribute is a
-user-defined function object or a class method object.
+user-defined :ref:`function object <user-defined-funcs>` or a
+:class:`classmethod` object.
+
+.. _method-binding:
 
 When an instance method object is created by retrieving a user-defined
-function object from a class via one of its instances, its
-:attr:`__self__` attribute is the instance, and the method object is said
-to be bound.  The new method's :attr:`__func__` attribute is the original
-function object.
-
-When an instance method object is created by retrieving a class method
-object from a class or instance, its :attr:`__self__` attribute is the
-class itself, and its :attr:`__func__` attribute is the function object
+:ref:`function object <user-defined-funcs>` from a class via one of its
+instances, its :attr:`~method.__self__` attribute is the instance, and the
+method object is said to be *bound*.  The new method's :attr:`~method.__func__`
+attribute is the original function object.
+
+When an instance method object is created by retrieving a :class:`classmethod`
+object from a class or instance, its :attr:`~method.__self__` attribute is the
+class itself, and its :attr:`~method.__func__` attribute is the function object
 underlying the class method.
 
 When an instance method object is called, the underlying function
-(:attr:`__func__`) is called, inserting the class instance
-(:attr:`__self__`) in front of the argument list.  For instance, when
+(:attr:`~method.__func__`) is called, inserting the class instance
+(:attr:`~method.__self__`) in front of the argument list.  For instance, when
 :class:`!C` is a class which contains a definition for a function
 :meth:`!f`, and ``x`` is an instance of :class:`!C`, calling ``x.f(1)`` is
 equivalent to calling ``C.f(x, 1)``.
 
-When an instance method object is derived from a class method object, the
-"class instance" stored in :attr:`__self__` will actually be the class
+When an instance method object is derived from a :class:`classmethod` object, the
+"class instance" stored in :attr:`~method.__self__` will actually be the class
 itself, so that calling either ``x.f(1)`` or ``C.f(1)`` is equivalent to
 calling ``f(C,1)`` where ``f`` is the underlying function.
 
-Note that the transformation from function object to instance method
+Note that the transformation from :ref:`function object <user-defined-funcs>`
+to instance method
 object happens each time the attribute is retrieved from the instance.  In
 some cases, a fruitful optimization is to assign the attribute to a local
 variable and call that local variable. Also notice that this
@@ -774,6 +797,8 @@ set to ``None`` (but see the next item); :attr:`__module__` is the name of
 the module the function was defined in or ``None`` if unavailable.
 
 
+.. _builtin-methods:
+
 Built-in methods
 ^^^^^^^^^^^^^^^^
 
@@ -785,8 +810,9 @@ Built-in methods
 This is really a different disguise of a built-in function, this time containing
 an object passed to the C function as an implicit extra argument.  An example of
 a built-in method is ``alist.append()``, assuming *alist* is a list object. In
-this case, the special read-only attribute :attr:`__self__` is set to the object
-denoted by *alist*.
+this case, the special read-only attribute :attr:`!__self__` is set to the object
+denoted by *alist*. (The attribute has the same semantics as it does with
+:attr:`other instance methods <method.__self__>`.)
 
 
 Classes
@@ -901,8 +927,9 @@ https://www.python.org/download/releases/2.3/mro/.
 
 When a class attribute reference (for class :class:`!C`, say) would yield a
 class method object, it is transformed into an instance method object whose
-:attr:`__self__` attribute is :class:`!C`.  When it would yield a static
-method object, it is transformed into the object wrapped by the static method
+:attr:`~method.__self__` attribute is :class:`!C`.
+When it would yield a :class:`staticmethod` object,
+it is transformed into the object wrapped by the static method
 object. See section :ref:`descriptors` for another way in which attributes
 retrieved from a class may differ from those actually contained in its
 :attr:`~object.__dict__`.
@@ -970,7 +997,7 @@ in which attribute references are searched.  When an attribute is not found
 there, and the instance's class has an attribute by that name, the search
 continues with the class attributes.  If a class attribute is found that is a
 user-defined function object, it is transformed into an instance method
-object whose :attr:`__self__` attribute is the instance.  Static method and
+object whose :attr:`~method.__self__` attribute is the instance.  Static method and
 class method objects are also transformed; see above under "Classes".  See
 section :ref:`descriptors` for another way in which attributes of a class
 retrieved via its instances may differ from the objects actually stored in

Doc/tutorial/classes.rst

@@ -769,8 +769,10 @@ data from a string buffer instead, and pass it as an argument.
    or arithmetic operators, and assigning such a "pseudo-file" to sys.stdin will
    not cause the interpreter to read further input from it.)
 
-Instance method objects have attributes, too: ``m.__self__`` is the instance
-object with the method :meth:`!m`, and ``m.__func__`` is the function object
+:ref:`Instance method objects <instance-methods>` have attributes, too:
+:attr:`m.__self__ <method.__self__>` is the instance
+object with the method :meth:`!m`, and :attr:`m.__func__ <method.__func__>` is
+the :ref:`function object <user-defined-funcs>`
 corresponding to the method.
 
 

Doc/whatsnew/2.6.rst

@@ -1678,8 +1678,8 @@ Some smaller changes made to the core Python language are:
 
 * Instance method objects have new attributes for the object and function
   comprising the method; the new synonym for :attr:`!im_self` is
-  :ref:`__self__ <instance-methods>`, and :attr:`!im_func` is also available as
-  :ref:`__func__ <instance-methods>`.
+  :attr:`~method.__self__`, and :attr:`!im_func` is also available as
+  :attr:`~method.__func__`.
   The old names are still supported in Python 2.6, but are gone in 3.0.
 
 * An obscure change: when you use the :func:`locals` function inside a

Doc/whatsnew/2.7.rst

@@ -858,9 +858,10 @@ Some smaller changes made to the core Python language are:
 
   .. XXX bytearray doesn't seem to be documented
 
-* When using ``@classmethod`` and ``@staticmethod`` to wrap
+* When using :class:`@classmethod <classmethod>` and
+  :class:`@staticmethod <staticmethod>` to wrap
   methods as class or static methods, the wrapper object now
-  exposes the wrapped function as their :ref:`__func__ <instance-methods>`
+  exposes the wrapped function as their :attr:`~method.__func__`
   attribute.
   (Contributed by Amaury Forgeot d'Arc, after a suggestion by
   George Sakkis; :issue:`5982`.)