[Python-checkins] cpython (2.7): Issue20467: clarify __init__'s role
ethan.furman
python-checkins at python.org
Thu Jan 15 07:02:41 CET 2015
https://hg.python.org/cpython/rev/7972b18b6e42
changeset: 94152:7972b18b6e42
branch: 2.7
parent: 94147:38826e21f0db
user: Ethan Furman <ethan at stoneleaf.us>
date: Wed Jan 14 22:02:10 2015 -0800
summary:
Issue20467: clarify __init__'s role
files:
Doc/reference/datamodel.rst | 12 ++++++++----
1 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -1225,13 +1225,17 @@
.. index:: pair: class; constructor
- Called when the instance is created. The arguments are those passed to the
+ Called after the instance has been created (by :meth:`__new__`), but before
+ it is returned to the caller. The arguments are those passed to the
class constructor expression. If a base class has an :meth:`__init__` method,
the derived class's :meth:`__init__` method, if any, must explicitly call it to
ensure proper initialization of the base class part of the instance; for
- example: ``BaseClass.__init__(self, [args...])``. As a special constraint on
- constructors, no value may be returned; doing so will cause a :exc:`TypeError`
- to be raised at runtime.
+ example: ``BaseClass.__init__(self, [args...])``.
+
+ Because :meth:`__new__` and :meth:`__init__` work together in constructing
+ objects (:meth:`__new__` to create it, and :meth:`__init__` to customise it),
+ no non-``None`` value may be returned by :meth:`__init__`; doing so will
+ cause a :exc:`TypeError` to be raised at runtime.
.. method:: object.__del__(self)
--
Repository URL: https://hg.python.org/cpython
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