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authorRaymond Hettinger <rhettinger@users.noreply.github.com>2020-11-02 04:15:50 (GMT)
committerGitHub <noreply@github.com>2020-11-02 04:15:50 (GMT)
commite9208f0e74d8c37542a750476ff272143fa8f67c (patch)
tree08453df36b571b0928f9c2c4c2259f47688c7caf /Doc
parentda7bb7b4d769350c5fd03e6cfb16b23dc265ed72 (diff)
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Minor formatting edits to the descriptor howto guide (GH-23092)
Diffstat (limited to 'Doc')
-rw-r--r--Doc/howto/descriptor.rst39
1 files changed, 20 insertions, 19 deletions
diff --git a/Doc/howto/descriptor.rst b/Doc/howto/descriptor.rst
index 5373025..fedf8a8 100644
--- a/Doc/howto/descriptor.rst
+++ b/Doc/howto/descriptor.rst
@@ -27,8 +27,9 @@ This guide has four major sections:
4) The last section has pure Python equivalents for built-in descriptors that
are written in C. Read this if you're curious about how functions turn
- into bound methods or about how to implement common tools like
- :func:`classmethod`, :func:`staticmethod`, and :func:`property`.
+ into bound methods or about the implementation of common tools like
+ :func:`classmethod`, :func:`staticmethod`, :func:`property`, and
+ :term:`__slots__`.
Primer
@@ -188,7 +189,7 @@ logged attribute and that its name is unchangeable. In the next example,
we'll fix that problem.
-Customized Names
+Customized names
----------------
When a class uses descriptors, it can inform each descriptor about what
@@ -438,7 +439,7 @@ creates a deeper understanding of how Python works and an appreciation for the
elegance of its design.
-Definition and Introduction
+Definition and introduction
---------------------------
In general, a descriptor is an object attribute with "binding behavior", one
@@ -463,7 +464,7 @@ simplify the underlying C code and offer a flexible set of new tools for
everyday Python programs.
-Descriptor Protocol
+Descriptor protocol
-------------------
``descr.__get__(self, obj, type=None) -> value``
@@ -493,7 +494,7 @@ called. Defining the :meth:`__set__` method with an exception raising
placeholder is enough to make it a data descriptor.
-Overview of Descriptor Invocation
+Overview of descriptor invocation
---------------------------------
A descriptor can be called directly with ``desc.__get__(obj)`` or
@@ -510,7 +511,7 @@ The details of invocation depend on whether ``obj`` is an object, class, or
instance of super.
-Invocation from an Instance
+Invocation from an instance
---------------------------
Instance lookup scans through a chain of namespaces giving data descriptors
@@ -549,7 +550,7 @@ The :exc:`TypeError` exception handler is needed because the instance dictionary
doesn't exist when its class defines :term:`__slots__`.
-Invocation from a Class
+Invocation from a class
-----------------------
The logic for a dotted lookup such as ``A.x`` is in
@@ -563,7 +564,7 @@ The full C implementation can be found in :c:func:`type_getattro()` and
:c:func:`_PyType_Lookup()` in :source:`Objects/typeobject.c`.
-Invocation from Super
+Invocation from super
---------------------
The logic for super's dotted lookup is in the :meth:`__getattribute__` method for
@@ -580,7 +581,7 @@ The full C implementation can be found in :c:func:`super_getattro()` in
<https://www.python.org/download/releases/2.2.3/descrintro/#cooperation>`_.
-Summary of Invocation Logic
+Summary of invocation logic
---------------------------
The mechanism for descriptors is embedded in the :meth:`__getattribute__()`
@@ -606,7 +607,7 @@ The important points to remember are:
* Non-data descriptors may be overridden by instance dictionaries.
-Automatic Name Notification
+Automatic name notification
---------------------------
Sometimes it is desirable for a descriptor to know what class variable name it
@@ -624,7 +625,7 @@ place at the time of class creation. If descriptors are added to the class
afterwards, :meth:`__set_name__` will need to be called manually.
-ORM Example
+ORM example
-----------
The following code is simplified skeleton showing how data descriptors could
@@ -694,8 +695,8 @@ Pure Python Equivalents
The descriptor protocol is simple and offers exciting possibilities. Several
use cases are so common that they have been prepackaged into built-in tools.
-Properties, bound methods, static methods, and class methods are all based on
-the descriptor protocol.
+Properties, bound methods, static methods, class methods, and \_\_slots\_\_ are
+all based on the descriptor protocol.
Properties
@@ -774,7 +775,7 @@ to wrap access to the value attribute in a property data descriptor::
return self._value
-Functions and Methods
+Functions and methods
---------------------
Python's object oriented features are built upon a function based environment.
@@ -858,7 +859,7 @@ If you have ever wondered where *self* comes from in regular methods or where
*cls* comes from in class methods, this is it!
-Static Methods
+Static methods
--------------
Non-data descriptors provide a simple mechanism for variations on the usual
@@ -926,7 +927,7 @@ Using the non-data descriptor protocol, a pure Python version of
return self.f
-Class Methods
+Class methods
-------------
Unlike static methods, class methods prepend the class reference to the
@@ -991,8 +992,8 @@ For example, a classmethod and property could be chained together::
def __doc__(cls):
return f'A doc for {cls.__name__!r}'
-Member Objects
---------------
+Member objects and __slots__
+----------------------------
When a class defines ``__slots__``, it replaces instance dictionaries with a
fixed-length array of slot values. From a user point of view that has