forked from AFPy/python-docs-fr
458 lines
15 KiB
Plaintext
458 lines
15 KiB
Plaintext
# Copyright (C) 2001-2018, Python Software Foundation
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# This file is distributed under the same license as the Python package.
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# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
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#
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#, fuzzy
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msgid ""
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msgstr ""
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"Project-Id-Version: Python 3.6\n"
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"Report-Msgid-Bugs-To: \n"
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"POT-Creation-Date: 2018-06-10 11:27+0200\n"
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"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
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"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
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"Language-Team: LANGUAGE <LL@li.org>\n"
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"Language: fr\n"
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"MIME-Version: 1.0\n"
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"Content-Type: text/plain; charset=UTF-8\n"
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"Content-Transfer-Encoding: 8bit\n"
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#: ../Doc/howto/descriptor.rst:3
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msgid "Descriptor HowTo Guide"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:0
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msgid "Author"
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msgstr "Auteur"
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#: ../Doc/howto/descriptor.rst:5
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msgid "Raymond Hettinger"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:0
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msgid "Contact"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:6
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msgid "<python at rcn dot com>"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:8
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msgid "Contents"
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msgstr "Sommaire"
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#: ../Doc/howto/descriptor.rst:11
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msgid "Abstract"
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msgstr "Résumé"
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#: ../Doc/howto/descriptor.rst:13
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msgid ""
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"Defines descriptors, summarizes the protocol, and shows how descriptors are "
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"called. Examines a custom descriptor and several built-in python "
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"descriptors including functions, properties, static methods, and class "
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"methods. Shows how each works by giving a pure Python equivalent and a "
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"sample application."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:18
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msgid ""
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"Learning about descriptors not only provides access to a larger toolset, it "
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"creates a deeper understanding of how Python works and an appreciation for "
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"the elegance of its design."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:24
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msgid "Definition and Introduction"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:26
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msgid ""
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"In general, a descriptor is an object attribute with \"binding behavior\", "
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"one whose attribute access has been overridden by methods in the descriptor "
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"protocol. Those methods are :meth:`__get__`, :meth:`__set__`, and :meth:"
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"`__delete__`. If any of those methods are defined for an object, it is said "
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"to be a descriptor."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:32
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msgid ""
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"The default behavior for attribute access is to get, set, or delete the "
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"attribute from an object's dictionary. For instance, ``a.x`` has a lookup "
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"chain starting with ``a.__dict__['x']``, then ``type(a).__dict__['x']``, and "
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"continuing through the base classes of ``type(a)`` excluding metaclasses. If "
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"the looked-up value is an object defining one of the descriptor methods, "
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"then Python may override the default behavior and invoke the descriptor "
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"method instead. Where this occurs in the precedence chain depends on which "
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"descriptor methods were defined."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:41
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msgid ""
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"Descriptors are a powerful, general purpose protocol. They are the "
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"mechanism behind properties, methods, static methods, class methods, and :"
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"func:`super()`. They are used throughout Python itself to implement the new "
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"style classes introduced in version 2.2. Descriptors simplify the "
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"underlying C-code and offer a flexible set of new tools for everyday Python "
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"programs."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:49
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msgid "Descriptor Protocol"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:51
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msgid "``descr.__get__(self, obj, type=None) --> value``"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:53
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msgid "``descr.__set__(self, obj, value) --> None``"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:55
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msgid "``descr.__delete__(self, obj) --> None``"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:57
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msgid ""
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"That is all there is to it. Define any of these methods and an object is "
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"considered a descriptor and can override default behavior upon being looked "
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"up as an attribute."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:61
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msgid ""
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"If an object defines both :meth:`__get__` and :meth:`__set__`, it is "
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"considered a data descriptor. Descriptors that only define :meth:`__get__` "
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"are called non-data descriptors (they are typically used for methods but "
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"other uses are possible)."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:66
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msgid ""
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"Data and non-data descriptors differ in how overrides are calculated with "
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"respect to entries in an instance's dictionary. If an instance's dictionary "
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"has an entry with the same name as a data descriptor, the data descriptor "
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"takes precedence. If an instance's dictionary has an entry with the same "
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"name as a non-data descriptor, the dictionary entry takes precedence."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:72
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msgid ""
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"To make a read-only data descriptor, define both :meth:`__get__` and :meth:"
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"`__set__` with the :meth:`__set__` raising an :exc:`AttributeError` when "
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"called. Defining the :meth:`__set__` method with an exception raising "
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"placeholder is enough to make it a data descriptor."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:79
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msgid "Invoking Descriptors"
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msgstr "Invocation des descripteurs"
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#: ../Doc/howto/descriptor.rst:81
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msgid ""
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"A descriptor can be called directly by its method name. For example, ``d."
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"__get__(obj)``."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:84
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msgid ""
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"Alternatively, it is more common for a descriptor to be invoked "
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"automatically upon attribute access. For example, ``obj.d`` looks up ``d`` "
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"in the dictionary of ``obj``. If ``d`` defines the method :meth:`__get__`, "
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"then ``d.__get__(obj)`` is invoked according to the precedence rules listed "
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"below."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:89
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msgid ""
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"The details of invocation depend on whether ``obj`` is an object or a class."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:91
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msgid ""
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"For objects, the machinery is in :meth:`object.__getattribute__` which "
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"transforms ``b.x`` into ``type(b).__dict__['x'].__get__(b, type(b))``. The "
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"implementation works through a precedence chain that gives data descriptors "
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"priority over instance variables, instance variables priority over non-data "
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"descriptors, and assigns lowest priority to :meth:`__getattr__` if provided. "
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"The full C implementation can be found in :c:func:"
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"`PyObject_GenericGetAttr()` in :source:`Objects/object.c`."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:99
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msgid ""
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"For classes, the machinery is in :meth:`type.__getattribute__` which "
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"transforms ``B.x`` into ``B.__dict__['x'].__get__(None, B)``. In pure "
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"Python, it looks like::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:110
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msgid "The important points to remember are:"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:112
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msgid "descriptors are invoked by the :meth:`__getattribute__` method"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:113
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msgid "overriding :meth:`__getattribute__` prevents automatic descriptor calls"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:114
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msgid ""
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":meth:`object.__getattribute__` and :meth:`type.__getattribute__` make "
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"different calls to :meth:`__get__`."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:116
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msgid "data descriptors always override instance dictionaries."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:117
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msgid "non-data descriptors may be overridden by instance dictionaries."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:119
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msgid ""
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"The object returned by ``super()`` also has a custom :meth:"
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"`__getattribute__` method for invoking descriptors. The call ``super(B, "
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"obj).m()`` searches ``obj.__class__.__mro__`` for the base class ``A`` "
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"immediately following ``B`` and then returns ``A.__dict__['m'].__get__(obj, "
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"B)``. If not a descriptor, ``m`` is returned unchanged. If not in the "
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"dictionary, ``m`` reverts to a search using :meth:`object.__getattribute__`."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:126
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msgid ""
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"The implementation details are in :c:func:`super_getattro()` in :source:"
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"`Objects/typeobject.c`. and a pure Python equivalent can be found in "
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"`Guido's Tutorial`_."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:132
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msgid ""
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"The details above show that the mechanism for descriptors is embedded in "
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"the :meth:`__getattribute__()` methods for :class:`object`, :class:`type`, "
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"and :func:`super`. Classes inherit this machinery when they derive from :"
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"class:`object` or if they have a meta-class providing similar functionality. "
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"Likewise, classes can turn-off descriptor invocation by overriding :meth:"
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"`__getattribute__()`."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:141
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msgid "Descriptor Example"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:143
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msgid ""
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"The following code creates a class whose objects are data descriptors which "
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"print a message for each get or set. Overriding :meth:`__getattribute__` is "
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"alternate approach that could do this for every attribute. However, this "
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"descriptor is useful for monitoring just a few chosen attributes::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:181
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msgid ""
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"The protocol is simple and offers exciting possibilities. Several use cases "
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"are so common that they have been packaged into individual function calls. "
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"Properties, bound methods, static methods, and class methods are all based "
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"on the descriptor protocol."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:188
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msgid "Properties"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:190
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msgid ""
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"Calling :func:`property` is a succinct way of building a data descriptor "
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"that triggers function calls upon access to an attribute. Its signature is::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:195
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msgid ""
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"The documentation shows a typical use to define a managed attribute ``x``::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:203
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msgid ""
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"To see how :func:`property` is implemented in terms of the descriptor "
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"protocol, here is a pure Python equivalent::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:243
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msgid ""
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"The :func:`property` builtin helps whenever a user interface has granted "
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"attribute access and then subsequent changes require the intervention of a "
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"method."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:247
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msgid ""
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"For instance, a spreadsheet class may grant access to a cell value through "
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"``Cell('b10').value``. Subsequent improvements to the program require the "
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"cell to be recalculated on every access; however, the programmer does not "
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"want to affect existing client code accessing the attribute directly. The "
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"solution is to wrap access to the value attribute in a property data "
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"descriptor::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:263
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msgid "Functions and Methods"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:265
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msgid ""
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"Python's object oriented features are built upon a function based "
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"environment. Using non-data descriptors, the two are merged seamlessly."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:268
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msgid ""
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"Class dictionaries store methods as functions. In a class definition, "
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"methods are written using :keyword:`def` or :keyword:`lambda`, the usual "
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"tools for creating functions. Methods only differ from regular functions in "
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"that the first argument is reserved for the object instance. By Python "
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"convention, the instance reference is called *self* but may be called *this* "
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"or any other variable name."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:275
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msgid ""
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"To support method calls, functions include the :meth:`__get__` method for "
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"binding methods during attribute access. This means that all functions are "
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"non-data descriptors which return bound methods when they are invoked from "
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"an object. In pure python, it works like this::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:288
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msgid ""
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"Running the interpreter shows how the function descriptor works in practice::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:326
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msgid "Static Methods and Class Methods"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:328
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msgid ""
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"Non-data descriptors provide a simple mechanism for variations on the usual "
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"patterns of binding functions into methods."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:331
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msgid ""
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"To recap, functions have a :meth:`__get__` method so that they can be "
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"converted to a method when accessed as attributes. The non-data descriptor "
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"transforms an ``obj.f(*args)`` call into ``f(obj, *args)``. Calling ``klass."
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"f(*args)`` becomes ``f(*args)``."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:336
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msgid "This chart summarizes the binding and its two most useful variants:"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:339
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msgid "Transformation"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:339
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msgid "Called from an Object"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:339
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msgid "Called from a Class"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:342
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msgid "function"
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msgstr "fonction"
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#: ../Doc/howto/descriptor.rst:342
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msgid "f(obj, \\*args)"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:342 ../Doc/howto/descriptor.rst:344
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msgid "f(\\*args)"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:344
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msgid "staticmethod"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:346
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msgid "classmethod"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:346
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msgid "f(type(obj), \\*args)"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:346
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msgid "f(klass, \\*args)"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:349
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msgid ""
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"Static methods return the underlying function without changes. Calling "
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"either ``c.f`` or ``C.f`` is the equivalent of a direct lookup into ``object."
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"__getattribute__(c, \"f\")`` or ``object.__getattribute__(C, \"f\")``. As a "
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"result, the function becomes identically accessible from either an object or "
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"a class."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:355
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msgid ""
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"Good candidates for static methods are methods that do not reference the "
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"``self`` variable."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:358
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msgid ""
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"For instance, a statistics package may include a container class for "
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"experimental data. The class provides normal methods for computing the "
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"average, mean, median, and other descriptive statistics that depend on the "
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"data. However, there may be useful functions which are conceptually related "
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"but do not depend on the data. For instance, ``erf(x)`` is handy conversion "
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"routine that comes up in statistical work but does not directly depend on a "
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"particular dataset. It can be called either from an object or the class: "
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"``s.erf(1.5) --> .9332`` or ``Sample.erf(1.5) --> .9332``."
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msgstr ""
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#: ../Doc/howto/descriptor.rst:367
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msgid ""
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"Since staticmethods return the underlying function with no changes, the "
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"example calls are unexciting::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:380
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msgid ""
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"Using the non-data descriptor protocol, a pure Python version of :func:"
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"`staticmethod` would look like this::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:392
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msgid ""
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"Unlike static methods, class methods prepend the class reference to the "
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"argument list before calling the function. This format is the same for "
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"whether the caller is an object or a class::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:407
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msgid ""
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"This behavior is useful whenever the function only needs to have a class "
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"reference and does not care about any underlying data. One use for "
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"classmethods is to create alternate class constructors. In Python 2.3, the "
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"classmethod :func:`dict.fromkeys` creates a new dictionary from a list of "
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"keys. The pure Python equivalent is::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:423
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msgid "Now a new dictionary of unique keys can be constructed like this::"
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msgstr ""
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#: ../Doc/howto/descriptor.rst:428
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msgid ""
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"Using the non-data descriptor protocol, a pure Python version of :func:"
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"`classmethod` would look like this::"
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msgstr ""
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