python-docs-fr/extending/newtypes.po

# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001-2016, Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Python 3.6\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2018-03-23 09:03+0100\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"Language: fr\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"

#: ../Doc/extending/newtypes.rst:8
msgid "Defining New Types"
msgstr ""

#: ../Doc/extending/newtypes.rst:15
msgid ""
"As mentioned in the last chapter, Python allows the writer of an extension "
"module to define new types that can be manipulated from Python code, much "
"like strings and lists in core Python."
msgstr ""

#: ../Doc/extending/newtypes.rst:19
msgid ""
"This is not hard; the code for all extension types follows a pattern, but "
"there are some details that you need to understand before you can get "
"started."
msgstr ""

#: ../Doc/extending/newtypes.rst:26
msgid "The Basics"
msgstr ""

#: ../Doc/extending/newtypes.rst:28
msgid ""
"The Python runtime sees all Python objects as variables of type :c:type:"
"`PyObject\\*`, which serves as a \"base type\" for all Python objects. :c:"
"type:`PyObject` itself only contains the refcount and a pointer to the "
"object's \"type object\".  This is where the action is; the type object "
"determines which (C) functions get called when, for instance, an attribute "
"gets looked up on an object or it is multiplied by another object.  These C "
"functions are called \"type methods\"."
msgstr ""

#: ../Doc/extending/newtypes.rst:36
msgid ""
"So, if you want to define a new object type, you need to create a new type "
"object."
msgstr ""

#: ../Doc/extending/newtypes.rst:39
msgid ""
"This sort of thing can only be explained by example, so here's a minimal, "
"but complete, module that defines a new type:"
msgstr ""

#: ../Doc/extending/newtypes.rst:45
msgid ""
"Now that's quite a bit to take in at once, but hopefully bits will seem "
"familiar from the last chapter."
msgstr ""

#: ../Doc/extending/newtypes.rst:48
msgid "The first bit that will be new is::"
msgstr ""

#: ../Doc/extending/newtypes.rst:54
msgid ""
"This is what a Noddy object will contain---in this case, nothing more than "
"what every Python object contains---a field called ``ob_base`` of type :c:"
"type:`PyObject`.  :c:type:`PyObject` in turn, contains an ``ob_refcnt`` "
"field and a pointer to a type object.  These can be accessed using the "
"macros :c:macro:`Py_REFCNT` and :c:macro:`Py_TYPE` respectively.  These are "
"the fields the :c:macro:`PyObject_HEAD` macro brings in.  The reason for the "
"macro is to standardize the layout and to enable special debugging fields in "
"debug builds."
msgstr ""

#: ../Doc/extending/newtypes.rst:62
msgid ""
"Note that there is no semicolon after the :c:macro:`PyObject_HEAD` macro; "
"one is included in the macro definition.  Be wary of adding one by accident; "
"it's easy to do from habit, and your compiler might not complain, but "
"someone else's probably will!  (On Windows, MSVC is known to call this an "
"error and refuse to compile the code.)"
msgstr ""

#: ../Doc/extending/newtypes.rst:68
msgid ""
"For contrast, let's take a look at the corresponding definition for standard "
"Python floats::"
msgstr ""

#: ../Doc/extending/newtypes.rst:76
msgid "Moving on, we come to the crunch --- the type object. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:102
msgid ""
"Now if you go and look up the definition of :c:type:`PyTypeObject` in :file:"
"`object.h` you'll see that it has many more fields that the definition "
"above.  The remaining fields will be filled with zeros by the C compiler, "
"and it's common practice to not specify them explicitly unless you need them."
msgstr ""

#: ../Doc/extending/newtypes.rst:107
msgid ""
"This is so important that we're going to pick the top of it apart still "
"further::"
msgstr ""

#: ../Doc/extending/newtypes.rst:112
msgid "This line is a bit of a wart; what we'd like to write is::"
msgstr ""

#: ../Doc/extending/newtypes.rst:116
msgid ""
"as the type of a type object is \"type\", but this isn't strictly conforming "
"C and some compilers complain.  Fortunately, this member will be filled in "
"for us by :c:func:`PyType_Ready`. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:122
msgid ""
"The name of our type.  This will appear in the default textual "
"representation of our objects and in some error messages, for example::"
msgstr ""

#: ../Doc/extending/newtypes.rst:130
msgid ""
"Note that the name is a dotted name that includes both the module name and "
"the name of the type within the module. The module in this case is :mod:"
"`noddy` and the type is :class:`Noddy`, so we set the type name to :class:"
"`noddy.Noddy`. One side effect of using an undotted name is that the pydoc "
"documentation tool will not list the new type in the module documentation. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:138
msgid ""
"This is so that Python knows how much memory to allocate when you call :c:"
"func:`PyObject_New`."
msgstr ""

#: ../Doc/extending/newtypes.rst:143
msgid ""
"If you want your type to be subclassable from Python, and your type has the "
"same :c:member:`~PyTypeObject.tp_basicsize` as its base type, you may have "
"problems with multiple inheritance.  A Python subclass of your type will "
"have to list your type first in its :attr:`~class.__bases__`, or else it "
"will not be able to call your type's :meth:`__new__` method without getting "
"an error.  You can avoid this problem by ensuring that your type has a "
"larger value for :c:member:`~PyTypeObject.tp_basicsize` than its base type "
"does.  Most of the time, this will be true anyway, because either your base "
"type will be :class:`object`, or else you will be adding data members to "
"your base type, and therefore increasing its size."
msgstr ""

#: ../Doc/extending/newtypes.rst:157
msgid ""
"This has to do with variable length objects like lists and strings. Ignore "
"this for now."
msgstr ""

#: ../Doc/extending/newtypes.rst:160
msgid ""
"Skipping a number of type methods that we don't provide, we set the class "
"flags to :const:`Py_TPFLAGS_DEFAULT`. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:165
msgid ""
"All types should include this constant in their flags.  It enables all of "
"the members defined until at least Python 3.3.  If you need further members, "
"you will need to OR the corresponding flags."
msgstr ""

#: ../Doc/extending/newtypes.rst:169
msgid ""
"We provide a doc string for the type in :c:member:`~PyTypeObject.tp_doc`. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:173
msgid ""
"Now we get into the type methods, the things that make your objects "
"different from the others.  We aren't going to implement any of these in "
"this version of the module.  We'll expand this example later to have more "
"interesting behavior."
msgstr ""

#: ../Doc/extending/newtypes.rst:177
msgid ""
"For now, all we want to be able to do is to create new :class:`Noddy` "
"objects. To enable object creation, we have to provide a :c:member:"
"`~PyTypeObject.tp_new` implementation. In this case, we can just use the "
"default implementation provided by the API function :c:func:"
"`PyType_GenericNew`.  We'd like to just assign this to the :c:member:"
"`~PyTypeObject.tp_new` slot, but we can't, for portability sake, On some "
"platforms or compilers, we can't statically initialize a structure member "
"with a function defined in another C module, so, instead, we'll assign the :"
"c:member:`~PyTypeObject.tp_new` slot in the module initialization function "
"just before calling :c:func:`PyType_Ready`::"
msgstr ""

#: ../Doc/extending/newtypes.rst:191
msgid ""
"All the other type methods are *NULL*, so we'll go over them later --- "
"that's for a later section!"
msgstr ""

#: ../Doc/extending/newtypes.rst:194
msgid ""
"Everything else in the file should be familiar, except for some code in :c:"
"func:`PyInit_noddy`::"
msgstr ""

#: ../Doc/extending/newtypes.rst:200
msgid ""
"This initializes the :class:`Noddy` type, filing in a number of members, "
"including :attr:`ob_type` that we initially set to *NULL*. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:205
msgid ""
"This adds the type to the module dictionary.  This allows us to create :"
"class:`Noddy` instances by calling the :class:`Noddy` class::"
msgstr ""

#: ../Doc/extending/newtypes.rst:211
msgid ""
"That's it!  All that remains is to build it; put the above code in a file "
"called :file:`noddy.c` and ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:218
msgid "in a file called :file:`setup.py`; then typing"
msgstr ""

#: ../Doc/extending/newtypes.rst:224
msgid ""
"at a shell should produce a file :file:`noddy.so` in a subdirectory; move to "
"that directory and fire up Python --- you should be able to ``import noddy`` "
"and play around with Noddy objects."
msgstr ""

#: ../Doc/extending/newtypes.rst:228
msgid "That wasn't so hard, was it?"
msgstr ""

#: ../Doc/extending/newtypes.rst:230
msgid ""
"Of course, the current Noddy type is pretty uninteresting. It has no data "
"and doesn't do anything. It can't even be subclassed."
msgstr ""

#: ../Doc/extending/newtypes.rst:235
msgid "Adding data and methods to the Basic example"
msgstr ""

#: ../Doc/extending/newtypes.rst:237
msgid ""
"Let's extend the basic example to add some data and methods.  Let's also "
"make the type usable as a base class. We'll create a new module, :mod:"
"`noddy2` that adds these capabilities:"
msgstr ""

#: ../Doc/extending/newtypes.rst:244
msgid "This version of the module has a number of changes."
msgstr ""

#: ../Doc/extending/newtypes.rst:246
msgid "We've added an extra include::"
msgstr ""

#: ../Doc/extending/newtypes.rst:250
msgid ""
"This include provides declarations that we use to handle attributes, as "
"described a bit later."
msgstr ""

#: ../Doc/extending/newtypes.rst:253
msgid ""
"The name of the :class:`Noddy` object structure has been shortened to :class:"
"`Noddy`.  The type object name has been shortened to :class:`NoddyType`."
msgstr ""

#: ../Doc/extending/newtypes.rst:256
msgid ""
"The  :class:`Noddy` type now has three data attributes, *first*, *last*, and "
"*number*.  The *first* and *last* variables are Python strings containing "
"first and last names. The *number* attribute is an integer."
msgstr ""

#: ../Doc/extending/newtypes.rst:260
msgid "The object structure is updated accordingly::"
msgstr ""

#: ../Doc/extending/newtypes.rst:269
msgid ""
"Because we now have data to manage, we have to be more careful about object "
"allocation and deallocation.  At a minimum, we need a deallocation method::"
msgstr ""

#: ../Doc/extending/newtypes.rst:280
msgid "which is assigned to the :c:member:`~PyTypeObject.tp_dealloc` member::"
msgstr ""

#: ../Doc/extending/newtypes.rst:284
msgid ""
"This method decrements the reference counts of the two Python attributes. We "
"use :c:func:`Py_XDECREF` here because the :attr:`first` and :attr:`last` "
"members could be *NULL*.  It then calls the :c:member:`~PyTypeObject."
"tp_free` member of the object's type to free the object's memory.  Note that "
"the object's type might not be :class:`NoddyType`, because the object may be "
"an instance of a subclass."
msgstr ""

#: ../Doc/extending/newtypes.rst:290
msgid ""
"We want to make sure that the first and last names are initialized to empty "
"strings, so we provide a new method::"
msgstr ""

#: ../Doc/extending/newtypes.rst:318
msgid "and install it in the :c:member:`~PyTypeObject.tp_new` member::"
msgstr ""

#: ../Doc/extending/newtypes.rst:322
msgid ""
"The new member is responsible for creating (as opposed to initializing) "
"objects of the type.  It is exposed in Python as the :meth:`__new__` "
"method.  See the paper titled \"Unifying types and classes in Python\" for a "
"detailed discussion of the :meth:`__new__` method.  One reason to implement "
"a new method is to assure the initial values of instance variables.  In this "
"case, we use the new method to make sure that the initial values of the "
"members :attr:`first` and :attr:`last` are not *NULL*. If we didn't care "
"whether the initial values were *NULL*, we could have used :c:func:"
"`PyType_GenericNew` as our new method, as we did before.  :c:func:"
"`PyType_GenericNew` initializes all of the instance variable members to "
"*NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:333
msgid ""
"The new method is a static method that is passed the type being instantiated "
"and any arguments passed when the type was called, and that returns the new "
"object created. New methods always accept positional and keyword arguments, "
"but they often ignore the arguments, leaving the argument handling to "
"initializer methods. Note that if the type supports subclassing, the type "
"passed may not be the type being defined.  The new method calls the :c:"
"member:`~PyTypeObject.tp_alloc` slot to allocate memory. We don't fill the :"
"c:member:`~PyTypeObject.tp_alloc` slot ourselves. Rather :c:func:"
"`PyType_Ready` fills it for us by inheriting it from our base class, which "
"is :class:`object` by default.  Most types use the default allocation."
msgstr ""

#: ../Doc/extending/newtypes.rst:345
msgid ""
"If you are creating a co-operative :c:member:`~PyTypeObject.tp_new` (one "
"that calls a base type's :c:member:`~PyTypeObject.tp_new` or :meth:"
"`__new__`), you must *not* try to determine what method to call using method "
"resolution order at runtime.  Always statically determine what type you are "
"going to call, and call its :c:member:`~PyTypeObject.tp_new` directly, or "
"via ``type->tp_base->tp_new``.  If you do not do this, Python subclasses of "
"your type that also inherit from other Python-defined classes may not work "
"correctly. (Specifically, you may not be able to create instances of such "
"subclasses without getting a :exc:`TypeError`.)"
msgstr ""

#: ../Doc/extending/newtypes.rst:354
msgid "We provide an initialization function::"
msgstr ""

#: ../Doc/extending/newtypes.rst:385
msgid "by filling the :c:member:`~PyTypeObject.tp_init` slot. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:389
msgid ""
"The :c:member:`~PyTypeObject.tp_init` slot is exposed in Python as the :meth:"
"`__init__` method. It is used to initialize an object after it's created. "
"Unlike the new method, we can't guarantee that the initializer is called.  "
"The initializer isn't called when unpickling objects and it can be "
"overridden.  Our initializer accepts arguments to provide initial values for "
"our instance. Initializers always accept positional and keyword arguments. "
"Initializers should return either ``0`` on success or ``-1`` on error."
msgstr ""

#: ../Doc/extending/newtypes.rst:397
msgid ""
"Initializers can be called multiple times.  Anyone can call the :meth:"
"`__init__` method on our objects.  For this reason, we have to be extra "
"careful when assigning the new values.  We might be tempted, for example to "
"assign the :attr:`first` member like this::"
msgstr ""

#: ../Doc/extending/newtypes.rst:408
msgid ""
"But this would be risky.  Our type doesn't restrict the type of the :attr:"
"`first` member, so it could be any kind of object.  It could have a "
"destructor that causes code to be executed that tries to access the :attr:"
"`first` member.  To be paranoid and protect ourselves against this "
"possibility, we almost always reassign members before decrementing their "
"reference counts.  When don't we have to do this?"
msgstr ""

#: ../Doc/extending/newtypes.rst:415
msgid "when we absolutely know that the reference count is greater than 1"
msgstr ""

#: ../Doc/extending/newtypes.rst:417
msgid ""
"when we know that deallocation of the object [#]_ will not cause any calls "
"back into our type's code"
msgstr ""

#: ../Doc/extending/newtypes.rst:420
msgid ""
"when decrementing a reference count in a :c:member:`~PyTypeObject."
"tp_dealloc` handler when garbage-collections is not supported [#]_"
msgstr ""

#: ../Doc/extending/newtypes.rst:423
msgid ""
"We want to expose our instance variables as attributes. There are a number "
"of ways to do that. The simplest way is to define member definitions::"
msgstr ""

#: ../Doc/extending/newtypes.rst:436
msgid ""
"and put the definitions in the :c:member:`~PyTypeObject.tp_members` slot::"
msgstr ""

#: ../Doc/extending/newtypes.rst:440
msgid ""
"Each member definition has a member name, type, offset, access flags and "
"documentation string. See the :ref:`Generic-Attribute-Management` section "
"below for details."
msgstr ""

#: ../Doc/extending/newtypes.rst:444
msgid ""
"A disadvantage of this approach is that it doesn't provide a way to restrict "
"the types of objects that can be assigned to the Python attributes.  We "
"expect the first and last names to be strings, but any Python objects can be "
"assigned. Further, the attributes can be deleted, setting the C pointers to "
"*NULL*.  Even though we can make sure the members are initialized to non-"
"*NULL* values, the members can be set to *NULL* if the attributes are "
"deleted."
msgstr ""

#: ../Doc/extending/newtypes.rst:451
msgid ""
"We define a single method, :meth:`name`, that outputs the objects name as "
"the concatenation of the first and last names. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:470
msgid ""
"The method is implemented as a C function that takes a :class:`Noddy` (or :"
"class:`Noddy` subclass) instance as the first argument.  Methods always take "
"an instance as the first argument. Methods often take positional and keyword "
"arguments as well, but in this case we don't take any and don't need to "
"accept a positional argument tuple or keyword argument dictionary. This "
"method is equivalent to the Python method::"
msgstr ""

#: ../Doc/extending/newtypes.rst:480
msgid ""
"Note that we have to check for the possibility that our :attr:`first` and :"
"attr:`last` members are *NULL*.  This is because they can be deleted, in "
"which case they are set to *NULL*.  It would be better to prevent deletion "
"of these attributes and to restrict the attribute values to be strings.  "
"We'll see how to do that in the next section."
msgstr ""

#: ../Doc/extending/newtypes.rst:486
msgid ""
"Now that we've defined the method, we need to create an array of method "
"definitions::"
msgstr ""

#: ../Doc/extending/newtypes.rst:496
msgid "and assign them to the :c:member:`~PyTypeObject.tp_methods` slot::"
msgstr ""

#: ../Doc/extending/newtypes.rst:500
msgid ""
"Note that we used the :const:`METH_NOARGS` flag to indicate that the method "
"is passed no arguments."
msgstr ""

#: ../Doc/extending/newtypes.rst:503
msgid ""
"Finally, we'll make our type usable as a base class.  We've written our "
"methods carefully so far so that they don't make any assumptions about the "
"type of the object being created or used, so all we need to do is to add "
"the :const:`Py_TPFLAGS_BASETYPE` to our class flag definition::"
msgstr ""

#: ../Doc/extending/newtypes.rst:510
msgid ""
"We rename :c:func:`PyInit_noddy` to :c:func:`PyInit_noddy2` and update the "
"module name in the :c:type:`PyModuleDef` struct."
msgstr ""

#: ../Doc/extending/newtypes.rst:513
msgid "Finally, we update our :file:`setup.py` file to build the new module::"
msgstr ""

#: ../Doc/extending/newtypes.rst:524
msgid "Providing finer control over data attributes"
msgstr ""

#: ../Doc/extending/newtypes.rst:526
msgid ""
"In this section, we'll provide finer control over how the :attr:`first` and :"
"attr:`last` attributes are set in the :class:`Noddy` example. In the "
"previous version of our module, the instance variables :attr:`first` and :"
"attr:`last` could be set to non-string values or even deleted. We want to "
"make sure that these attributes always contain strings."
msgstr ""

#: ../Doc/extending/newtypes.rst:535
msgid ""
"To provide greater control, over the :attr:`first` and :attr:`last` "
"attributes, we'll use custom getter and setter functions.  Here are the "
"functions for getting and setting the :attr:`first` attribute::"
msgstr ""

#: ../Doc/extending/newtypes.rst:566
msgid ""
"The getter function is passed a :class:`Noddy` object and a \"closure\", "
"which is void pointer. In this case, the closure is ignored. (The closure "
"supports an advanced usage in which definition data is passed to the getter "
"and setter. This could, for example, be used to allow a single set of getter "
"and setter functions that decide the attribute to get or set based on data "
"in the closure.)"
msgstr ""

#: ../Doc/extending/newtypes.rst:572
msgid ""
"The setter function is passed the :class:`Noddy` object, the new value, and "
"the closure. The new value may be *NULL*, in which case the attribute is "
"being deleted.  In our setter, we raise an error if the attribute is deleted "
"or if the attribute value is not a string."
msgstr ""

#: ../Doc/extending/newtypes.rst:577
msgid "We create an array of :c:type:`PyGetSetDef` structures::"
msgstr ""

#: ../Doc/extending/newtypes.rst:591
msgid "and register it in the :c:member:`~PyTypeObject.tp_getset` slot::"
msgstr ""

#: ../Doc/extending/newtypes.rst:595
msgid "to register our attribute getters and setters."
msgstr ""

#: ../Doc/extending/newtypes.rst:597
msgid ""
"The last item in a :c:type:`PyGetSetDef` structure is the closure mentioned "
"above. In this case, we aren't using the closure, so we just pass *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:600
msgid "We also remove the member definitions for these attributes::"
msgstr ""

#: ../Doc/extending/newtypes.rst:608
msgid ""
"We also need to update the :c:member:`~PyTypeObject.tp_init` handler to only "
"allow strings [#]_ to be passed::"
msgstr ""

#: ../Doc/extending/newtypes.rst:640
msgid ""
"With these changes, we can assure that the :attr:`first` and :attr:`last` "
"members are never *NULL* so we can remove checks for *NULL* values in almost "
"all cases. This means that most of the :c:func:`Py_XDECREF` calls can be "
"converted to :c:func:`Py_DECREF` calls. The only place we can't change these "
"calls is in the deallocator, where there is the possibility that the "
"initialization of these members failed in the constructor."
msgstr ""

#: ../Doc/extending/newtypes.rst:647
msgid ""
"We also rename the module initialization function and module name in the "
"initialization function, as we did before, and we add an extra definition to "
"the :file:`setup.py` file."
msgstr ""

#: ../Doc/extending/newtypes.rst:653
msgid "Supporting cyclic garbage collection"
msgstr ""

#: ../Doc/extending/newtypes.rst:655
msgid ""
"Python has a cyclic-garbage collector that can identify unneeded objects "
"even when their reference counts are not zero. This can happen when objects "
"are involved in cycles.  For example, consider::"
msgstr ""

#: ../Doc/extending/newtypes.rst:663
msgid ""
"In this example, we create a list that contains itself. When we delete it, "
"it still has a reference from itself. Its reference count doesn't drop to "
"zero. Fortunately, Python's cyclic-garbage collector will eventually figure "
"out that the list is garbage and free it."
msgstr ""

#: ../Doc/extending/newtypes.rst:668
msgid ""
"In the second version of the :class:`Noddy` example, we allowed any kind of "
"object to be stored in the :attr:`first` or :attr:`last` attributes [#]_. "
"This means that :class:`Noddy` objects can participate in cycles::"
msgstr ""

#: ../Doc/extending/newtypes.rst:677
msgid ""
"This is pretty silly, but it gives us an excuse to add support for the "
"cyclic-garbage collector to the :class:`Noddy` example.  To support cyclic "
"garbage collection, types need to fill two slots and set a class flag that "
"enables these slots:"
msgstr ""

#: ../Doc/extending/newtypes.rst:685
msgid ""
"The traversal method provides access to subobjects that could participate in "
"cycles::"
msgstr ""

#: ../Doc/extending/newtypes.rst:707
msgid ""
"For each subobject that can participate in cycles, we need to call the :c:"
"func:`visit` function, which is passed to the traversal method. The :c:func:"
"`visit` function takes as arguments the subobject and the extra argument "
"*arg* passed to the traversal method.  It returns an integer value that must "
"be returned if it is non-zero."
msgstr ""

#: ../Doc/extending/newtypes.rst:713
msgid ""
"Python provides a :c:func:`Py_VISIT` macro that automates calling visit "
"functions.  With :c:func:`Py_VISIT`, :c:func:`Noddy_traverse` can be "
"simplified::"
msgstr ""

#: ../Doc/extending/newtypes.rst:726
msgid ""
"Note that the :c:member:`~PyTypeObject.tp_traverse` implementation must name "
"its arguments exactly *visit* and *arg* in order to use :c:func:`Py_VISIT`.  "
"This is to encourage uniformity across these boring implementations."
msgstr ""

#: ../Doc/extending/newtypes.rst:730
msgid ""
"We also need to provide a method for clearing any subobjects that can "
"participate in cycles."
msgstr ""

#: ../Doc/extending/newtypes.rst:751
msgid ""
"Notice the use of a temporary variable in :c:func:`Noddy_clear`. We use the "
"temporary variable so that we can set each member to *NULL* before "
"decrementing its reference count.  We do this because, as was discussed "
"earlier, if the reference count drops to zero, we might cause code to run "
"that calls back into the object.  In addition, because we now support "
"garbage collection, we also have to worry about code being run that triggers "
"garbage collection.  If garbage collection is run, our :c:member:"
"`~PyTypeObject.tp_traverse` handler could get called. We can't take a chance "
"of having :c:func:`Noddy_traverse` called when a member's reference count "
"has dropped to zero and its value hasn't been set to *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:761
msgid ""
"Python provides a :c:func:`Py_CLEAR` that automates the careful decrementing "
"of reference counts.  With :c:func:`Py_CLEAR`, the :c:func:`Noddy_clear` "
"function can be simplified::"
msgstr ""

#: ../Doc/extending/newtypes.rst:773
msgid ""
"Note that :c:func:`Noddy_dealloc` may call arbitrary functions through "
"``__del__`` method or weakref callback. It means circular GC can be "
"triggered inside the function.  Since GC assumes reference count is not "
"zero, we need to untrack the object from GC by calling :c:func:"
"`PyObject_GC_UnTrack` before clearing members. Here is reimplemented "
"deallocator which uses :c:func:`PyObject_GC_UnTrack` and :c:func:"
"`Noddy_clear`."
msgstr ""

#: ../Doc/extending/newtypes.rst:790
msgid ""
"Finally, we add the :const:`Py_TPFLAGS_HAVE_GC` flag to the class flags::"
msgstr ""

#: ../Doc/extending/newtypes.rst:794
msgid ""
"That's pretty much it.  If we had written custom :c:member:`~PyTypeObject."
"tp_alloc` or :c:member:`~PyTypeObject.tp_free` slots, we'd need to modify "
"them for cyclic-garbage collection. Most extensions will use the versions "
"automatically provided."
msgstr ""

#: ../Doc/extending/newtypes.rst:800
msgid "Subclassing other types"
msgstr ""

#: ../Doc/extending/newtypes.rst:802
msgid ""
"It is possible to create new extension types that are derived from existing "
"types. It is easiest to inherit from the built in types, since an extension "
"can easily use the :class:`PyTypeObject` it needs. It can be difficult to "
"share these :class:`PyTypeObject` structures between extension modules."
msgstr ""

#: ../Doc/extending/newtypes.rst:807
msgid ""
"In this example we will create a :class:`Shoddy` type that inherits from the "
"built-in :class:`list` type. The new type will be completely compatible with "
"regular lists, but will have an additional :meth:`increment` method that "
"increases an internal counter. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:825
msgid ""
"As you can see, the source code closely resembles the :class:`Noddy` "
"examples in previous sections. We will break down the main differences "
"between them. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:833
msgid ""
"The primary difference for derived type objects is that the base type's "
"object structure must be the first value. The base type will already include "
"the :c:func:`PyObject_HEAD` at the beginning of its structure."
msgstr ""

#: ../Doc/extending/newtypes.rst:837
msgid ""
"When a Python object is a :class:`Shoddy` instance, its *PyObject\\** "
"pointer can be safely cast to both *PyListObject\\** and *Shoddy\\**. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:849
msgid ""
"In the :attr:`__init__` method for our type, we can see how to call through "
"to the :attr:`__init__` method of the base type."
msgstr ""

#: ../Doc/extending/newtypes.rst:852
msgid ""
"This pattern is important when writing a type with custom :attr:`new` and :"
"attr:`dealloc` methods. The :attr:`new` method should not actually create "
"the memory for the object with :c:member:`~PyTypeObject.tp_alloc`, that will "
"be handled by the base class when calling its :c:member:`~PyTypeObject."
"tp_new`."
msgstr ""

#: ../Doc/extending/newtypes.rst:857
msgid ""
"When filling out the :c:func:`PyTypeObject` for the :class:`Shoddy` type, "
"you see a slot for :c:func:`tp_base`. Due to cross platform compiler issues, "
"you can't fill that field directly with the :c:func:`PyList_Type`; it can be "
"done later in the module's :c:func:`init` function. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:880
msgid ""
"Before calling :c:func:`PyType_Ready`, the type structure must have the :c:"
"member:`~PyTypeObject.tp_base` slot filled in. When we are deriving a new "
"type, it is not necessary to fill out the :c:member:`~PyTypeObject.tp_alloc` "
"slot with :c:func:`PyType_GenericNew` -- the allocate function from the base "
"type will be inherited."
msgstr ""

#: ../Doc/extending/newtypes.rst:885
msgid ""
"After that, calling :c:func:`PyType_Ready` and adding the type object to the "
"module is the same as with the basic :class:`Noddy` examples."
msgstr ""

#: ../Doc/extending/newtypes.rst:892
msgid "Type Methods"
msgstr ""

#: ../Doc/extending/newtypes.rst:894
msgid ""
"This section aims to give a quick fly-by on the various type methods you can "
"implement and what they do."
msgstr ""

#: ../Doc/extending/newtypes.rst:897
msgid ""
"Here is the definition of :c:type:`PyTypeObject`, with some fields only used "
"in debug builds omitted:"
msgstr ""

#: ../Doc/extending/newtypes.rst:903
msgid ""
"Now that's a *lot* of methods.  Don't worry too much though - if you have a "
"type you want to define, the chances are very good that you will only "
"implement a handful of these."
msgstr ""

#: ../Doc/extending/newtypes.rst:907
msgid ""
"As you probably expect by now, we're going to go over this and give more "
"information about the various handlers.  We won't go in the order they are "
"defined in the structure, because there is a lot of historical baggage that "
"impacts the ordering of the fields; be sure your type initialization keeps "
"the fields in the right order!  It's often easiest to find an example that "
"includes all the fields you need (even if they're initialized to ``0``) and "
"then change the values to suit your new type. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:917
msgid ""
"The name of the type - as mentioned in the last section, this will appear in "
"various places, almost entirely for diagnostic purposes. Try to choose "
"something that will be helpful in such a situation! ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:923
msgid ""
"These fields tell the runtime how much memory to allocate when new objects "
"of this type are created.  Python has some built-in support for variable "
"length structures (think: strings, lists) which is where the :c:member:"
"`~PyTypeObject.tp_itemsize` field comes in.  This will be dealt with "
"later. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:930
msgid ""
"Here you can put a string (or its address) that you want returned when the "
"Python script references ``obj.__doc__`` to retrieve the doc string."
msgstr ""

#: ../Doc/extending/newtypes.rst:933
msgid ""
"Now we come to the basic type methods---the ones most extension types will "
"implement."
msgstr ""

#: ../Doc/extending/newtypes.rst:938
msgid "Finalization and De-allocation"
msgstr ""

#: ../Doc/extending/newtypes.rst:950
msgid ""
"This function is called when the reference count of the instance of your "
"type is reduced to zero and the Python interpreter wants to reclaim it.  If "
"your type has memory to free or other clean-up to perform, you can put it "
"here.  The object itself needs to be freed here as well.  Here is an example "
"of this function::"
msgstr ""

#: ../Doc/extending/newtypes.rst:967
msgid ""
"One important requirement of the deallocator function is that it leaves any "
"pending exceptions alone.  This is important since deallocators are "
"frequently called as the interpreter unwinds the Python stack; when the "
"stack is unwound due to an exception (rather than normal returns), nothing "
"is done to protect the deallocators from seeing that an exception has "
"already been set.  Any actions which a deallocator performs which may cause "
"additional Python code to be executed may detect that an exception has been "
"set.  This can lead to misleading errors from the interpreter.  The proper "
"way to protect against this is to save a pending exception before performing "
"the unsafe action, and restoring it when done.  This can be done using the :"
"c:func:`PyErr_Fetch` and :c:func:`PyErr_Restore` functions::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1006
msgid ""
"There are limitations to what you can safely do in a deallocator function. "
"First, if your type supports garbage collection (using :c:member:"
"`~PyTypeObject.tp_traverse` and/or :c:member:`~PyTypeObject.tp_clear`), some "
"of the object's members can have been cleared or finalized by the time :c:"
"member:`~PyTypeObject.tp_dealloc` is called.  Second, in :c:member:"
"`~PyTypeObject.tp_dealloc`, your object is in an unstable state: its "
"reference count is equal to zero.  Any call to a non-trivial object or API "
"(as in the example above) might end up calling :c:member:`~PyTypeObject."
"tp_dealloc` again, causing a double free and a crash."
msgstr ""

#: ../Doc/extending/newtypes.rst:1015
msgid ""
"Starting with Python 3.4, it is recommended not to put any complex "
"finalization code in :c:member:`~PyTypeObject.tp_dealloc`, and instead use "
"the new :c:member:`~PyTypeObject.tp_finalize` type method."
msgstr ""

#: ../Doc/extending/newtypes.rst:1020
msgid ":pep:`442` explains the new finalization scheme."
msgstr ""

#: ../Doc/extending/newtypes.rst:1027
msgid "Object Presentation"
msgstr ""

#: ../Doc/extending/newtypes.rst:1029
msgid ""
"In Python, there are two ways to generate a textual representation of an "
"object: the :func:`repr` function, and the :func:`str` function.  (The :func:"
"`print` function just calls :func:`str`.)  These handlers are both optional."
msgstr ""

#: ../Doc/extending/newtypes.rst:1038
msgid ""
"The :c:member:`~PyTypeObject.tp_repr` handler should return a string object "
"containing a representation of the instance for which it is called.  Here is "
"a simple example::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1049
msgid ""
"If no :c:member:`~PyTypeObject.tp_repr` handler is specified, the "
"interpreter will supply a representation that uses the type's :c:member:"
"`~PyTypeObject.tp_name` and a uniquely-identifying value for the object."
msgstr ""

#: ../Doc/extending/newtypes.rst:1053
msgid ""
"The :c:member:`~PyTypeObject.tp_str` handler is to :func:`str` what the :c:"
"member:`~PyTypeObject.tp_repr` handler described above is to :func:`repr`; "
"that is, it is called when Python code calls :func:`str` on an instance of "
"your object.  Its implementation is very similar to the :c:member:"
"`~PyTypeObject.tp_repr` function, but the resulting string is intended for "
"human consumption.  If :c:member:`~PyTypeObject.tp_str` is not specified, "
"the :c:member:`~PyTypeObject.tp_repr` handler is used instead."
msgstr ""

#: ../Doc/extending/newtypes.rst:1060
msgid "Here is a simple example::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1072
msgid "Attribute Management"
msgstr ""

#: ../Doc/extending/newtypes.rst:1074
msgid ""
"For every object which can support attributes, the corresponding type must "
"provide the functions that control how the attributes are resolved.  There "
"needs to be a function which can retrieve attributes (if any are defined), "
"and another to set attributes (if setting attributes is allowed).  Removing "
"an attribute is a special case, for which the new value passed to the "
"handler is *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:1080
msgid ""
"Python supports two pairs of attribute handlers; a type that supports "
"attributes only needs to implement the functions for one pair.  The "
"difference is that one pair takes the name of the attribute as a :c:type:"
"`char\\*`, while the other accepts a :c:type:`PyObject\\*`.  Each type can "
"use whichever pair makes more sense for the implementation's convenience. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1092
msgid ""
"If accessing attributes of an object is always a simple operation (this will "
"be explained shortly), there are generic implementations which can be used "
"to provide the :c:type:`PyObject\\*` version of the attribute management "
"functions. The actual need for type-specific attribute handlers almost "
"completely disappeared starting with Python 2.2, though there are many "
"examples which have not been updated to use some of the new generic "
"mechanism that is available."
msgstr ""

#: ../Doc/extending/newtypes.rst:1103
msgid "Generic Attribute Management"
msgstr ""

#: ../Doc/extending/newtypes.rst:1105
msgid ""
"Most extension types only use *simple* attributes.  So, what makes the "
"attributes simple?  There are only a couple of conditions that must be met:"
msgstr ""

#: ../Doc/extending/newtypes.rst:1108
msgid ""
"The name of the attributes must be known when :c:func:`PyType_Ready` is "
"called."
msgstr ""

#: ../Doc/extending/newtypes.rst:1111
msgid ""
"No special processing is needed to record that an attribute was looked up or "
"set, nor do actions need to be taken based on the value."
msgstr ""

#: ../Doc/extending/newtypes.rst:1114
msgid ""
"Note that this list does not place any restrictions on the values of the "
"attributes, when the values are computed, or how relevant data is stored."
msgstr ""

#: ../Doc/extending/newtypes.rst:1117
msgid ""
"When :c:func:`PyType_Ready` is called, it uses three tables referenced by "
"the type object to create :term:`descriptor`\\s which are placed in the "
"dictionary of the type object.  Each descriptor controls access to one "
"attribute of the instance object.  Each of the tables is optional; if all "
"three are *NULL*, instances of the type will only have attributes that are "
"inherited from their base type, and should leave the :c:member:"
"`~PyTypeObject.tp_getattro` and :c:member:`~PyTypeObject.tp_setattro` fields "
"*NULL* as well, allowing the base type to handle attributes."
msgstr ""

#: ../Doc/extending/newtypes.rst:1125
msgid "The tables are declared as three fields of the type object::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1131
msgid ""
"If :c:member:`~PyTypeObject.tp_methods` is not *NULL*, it must refer to an "
"array of :c:type:`PyMethodDef` structures.  Each entry in the table is an "
"instance of this structure::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1142
msgid ""
"One entry should be defined for each method provided by the type; no entries "
"are needed for methods inherited from a base type.  One additional entry is "
"needed at the end; it is a sentinel that marks the end of the array.  The :"
"attr:`ml_name` field of the sentinel must be *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:1147
msgid ""
"The second table is used to define attributes which map directly to data "
"stored in the instance.  A variety of primitive C types are supported, and "
"access may be read-only or read-write.  The structures in the table are "
"defined as::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1159
msgid ""
"For each entry in the table, a :term:`descriptor` will be constructed and "
"added to the type which will be able to extract a value from the instance "
"structure.  The :attr:`type` field should contain one of the type codes "
"defined in the :file:`structmember.h` header; the value will be used to "
"determine how to convert Python values to and from C values.  The :attr:"
"`flags` field is used to store flags which control how the attribute can be "
"accessed."
msgstr ""

#: ../Doc/extending/newtypes.rst:1166
msgid ""
"The following flag constants are defined in :file:`structmember.h`; they may "
"be combined using bitwise-OR."
msgstr ""

#: ../Doc/extending/newtypes.rst:1170
msgid "Constant"
msgstr "Constante"

#: ../Doc/extending/newtypes.rst:1170
msgid "Meaning"
msgstr "Signification"

#: ../Doc/extending/newtypes.rst:1172
msgid ":const:`READONLY`"
msgstr ""

#: ../Doc/extending/newtypes.rst:1172
msgid "Never writable."
msgstr ""

#: ../Doc/extending/newtypes.rst:1174
msgid ":const:`READ_RESTRICTED`"
msgstr ""

#: ../Doc/extending/newtypes.rst:1174
msgid "Not readable in restricted mode."
msgstr ""

#: ../Doc/extending/newtypes.rst:1176
msgid ":const:`WRITE_RESTRICTED`"
msgstr ""

#: ../Doc/extending/newtypes.rst:1176
msgid "Not writable in restricted mode."
msgstr ""

#: ../Doc/extending/newtypes.rst:1178
msgid ":const:`RESTRICTED`"
msgstr ""

#: ../Doc/extending/newtypes.rst:1178
msgid "Not readable or writable in restricted mode."
msgstr ""

#: ../Doc/extending/newtypes.rst:1187
msgid ""
"An interesting advantage of using the :c:member:`~PyTypeObject.tp_members` "
"table to build descriptors that are used at runtime is that any attribute "
"defined this way can have an associated doc string simply by providing the "
"text in the table.  An application can use the introspection API to retrieve "
"the descriptor from the class object, and get the doc string using its :attr:"
"`__doc__` attribute."
msgstr ""

#: ../Doc/extending/newtypes.rst:1193
msgid ""
"As with the :c:member:`~PyTypeObject.tp_methods` table, a sentinel entry "
"with a :attr:`name` value of *NULL* is required."
msgstr ""

#: ../Doc/extending/newtypes.rst:1207
msgid "Type-specific Attribute Management"
msgstr ""

#: ../Doc/extending/newtypes.rst:1209
msgid ""
"For simplicity, only the :c:type:`char\\*` version will be demonstrated "
"here; the type of the name parameter is the only difference between the :c:"
"type:`char\\*` and :c:type:`PyObject\\*` flavors of the interface. This "
"example effectively does the same thing as the generic example above, but "
"does not use the generic support added in Python 2.2.  It explains how the "
"handler functions are called, so that if you do need to extend their "
"functionality, you'll understand what needs to be done."
msgstr ""

#: ../Doc/extending/newtypes.rst:1217
msgid ""
"The :c:member:`~PyTypeObject.tp_getattr` handler is called when the object "
"requires an attribute look-up.  It is called in the same situations where "
"the :meth:`__getattr__` method of a class would be called."
msgstr ""

#: ../Doc/extending/newtypes.rst:1221
msgid "Here is an example::"
msgstr "Voici un exemple : ::"

#: ../Doc/extending/newtypes.rst:1237
msgid ""
"The :c:member:`~PyTypeObject.tp_setattr` handler is called when the :meth:"
"`__setattr__` or :meth:`__delattr__` method of a class instance would be "
"called.  When an attribute should be deleted, the third parameter will be "
"*NULL*.  Here is an example that simply raises an exception; if this were "
"really all you wanted, the :c:member:`~PyTypeObject.tp_setattr` handler "
"should be set to *NULL*. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1251
msgid "Object Comparison"
msgstr ""

#: ../Doc/extending/newtypes.rst:1257
msgid ""
"The :c:member:`~PyTypeObject.tp_richcompare` handler is called when "
"comparisons are needed.  It is analogous to the :ref:`rich comparison "
"methods <richcmpfuncs>`, like :meth:`__lt__`, and also called by :c:func:"
"`PyObject_RichCompare` and :c:func:`PyObject_RichCompareBool`."
msgstr ""

#: ../Doc/extending/newtypes.rst:1262
msgid ""
"This function is called with two Python objects and the operator as "
"arguments, where the operator is one of ``Py_EQ``, ``Py_NE``, ``Py_LE``, "
"``Py_GT``, ``Py_LT`` or ``Py_GT``.  It should compare the two objects with "
"respect to the specified operator and return ``Py_True`` or ``Py_False`` if "
"the comparison is successful, ``Py_NotImplemented`` to indicate that "
"comparison is not implemented and the other object's comparison method "
"should be tried, or *NULL* if an exception was set."
msgstr ""

#: ../Doc/extending/newtypes.rst:1270
msgid ""
"Here is a sample implementation, for a datatype that is considered equal if "
"the size of an internal pointer is equal::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1300
msgid "Abstract Protocol Support"
msgstr ""

#: ../Doc/extending/newtypes.rst:1302
msgid ""
"Python supports a variety of *abstract* 'protocols;' the specific interfaces "
"provided to use these interfaces are documented in :ref:`abstract`."
msgstr ""

#: ../Doc/extending/newtypes.rst:1306
msgid ""
"A number of these abstract interfaces were defined early in the development "
"of the Python implementation.  In particular, the number, mapping, and "
"sequence protocols have been part of Python since the beginning.  Other "
"protocols have been added over time.  For protocols which depend on several "
"handler routines from the type implementation, the older protocols have been "
"defined as optional blocks of handlers referenced by the type object.  For "
"newer protocols there are additional slots in the main type object, with a "
"flag bit being set to indicate that the slots are present and should be "
"checked by the interpreter.  (The flag bit does not indicate that the slot "
"values are non-*NULL*. The flag may be set to indicate the presence of a "
"slot, but a slot may still be unfilled.) ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1321
msgid ""
"If you wish your object to be able to act like a number, a sequence, or a "
"mapping object, then you place the address of a structure that implements "
"the C type :c:type:`PyNumberMethods`, :c:type:`PySequenceMethods`, or :c:"
"type:`PyMappingMethods`, respectively. It is up to you to fill in this "
"structure with appropriate values. You can find examples of the use of each "
"of these in the :file:`Objects` directory of the Python source "
"distribution. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1330
msgid ""
"This function, if you choose to provide it, should return a hash number for "
"an instance of your data type. Here is a moderately pointless example::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1346
msgid ""
"This function is called when an instance of your data type is \"called\", "
"for example, if ``obj1`` is an instance of your data type and the Python "
"script contains ``obj1('hello')``, the :c:member:`~PyTypeObject.tp_call` "
"handler is invoked."
msgstr ""

#: ../Doc/extending/newtypes.rst:1350
msgid "This function takes three arguments:"
msgstr ""

#: ../Doc/extending/newtypes.rst:1352
msgid ""
"*arg1* is the instance of the data type which is the subject of the call. If "
"the call is ``obj1('hello')``, then *arg1* is ``obj1``."
msgstr ""

#: ../Doc/extending/newtypes.rst:1355
msgid ""
"*arg2* is a tuple containing the arguments to the call.  You can use :c:func:"
"`PyArg_ParseTuple` to extract the arguments."
msgstr ""

#: ../Doc/extending/newtypes.rst:1358
msgid ""
"*arg3* is a dictionary of keyword arguments that were passed. If this is non-"
"*NULL* and you support keyword arguments, use :c:func:"
"`PyArg_ParseTupleAndKeywords` to extract the arguments.  If you do not want "
"to support keyword arguments and this is non-*NULL*, raise a :exc:"
"`TypeError` with a message saying that keyword arguments are not supported."
msgstr ""

#: ../Doc/extending/newtypes.rst:1364
msgid ""
"Here is a desultory example of the implementation of the call function. ::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1395
msgid ""
"These functions provide support for the iterator protocol.  Any object which "
"wishes to support iteration over its contents (which may be generated during "
"iteration) must implement the ``tp_iter`` handler.  Objects which are "
"returned by a ``tp_iter`` handler must implement both the ``tp_iter`` and "
"``tp_iternext`` handlers. Both handlers take exactly one parameter, the "
"instance for which they are being called, and return a new reference.  In "
"the case of an error, they should set an exception and return *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:1403
msgid ""
"For an object which represents an iterable collection, the ``tp_iter`` "
"handler must return an iterator object.  The iterator object is responsible "
"for maintaining the state of the iteration.  For collections which can "
"support multiple iterators which do not interfere with each other (as lists "
"and tuples do), a new iterator should be created and returned.  Objects "
"which can only be iterated over once (usually due to side effects of "
"iteration) should implement this handler by returning a new reference to "
"themselves, and should also implement the ``tp_iternext`` handler.  File "
"objects are an example of such an iterator."
msgstr ""

#: ../Doc/extending/newtypes.rst:1413
msgid ""
"Iterator objects should implement both handlers.  The ``tp_iter`` handler "
"should return a new reference to the iterator (this is the same as the "
"``tp_iter`` handler for objects which can only be iterated over "
"destructively).  The ``tp_iternext`` handler should return a new reference "
"to the next object in the iteration if there is one.  If the iteration has "
"reached the end, it may return *NULL* without setting an exception or it may "
"set :exc:`StopIteration`; avoiding the exception can yield slightly better "
"performance.  If an actual error occurs, it should set an exception and "
"return *NULL*."
msgstr ""

#: ../Doc/extending/newtypes.rst:1426
msgid "Weak Reference Support"
msgstr ""

#: ../Doc/extending/newtypes.rst:1428
msgid ""
"One of the goals of Python's weak-reference implementation is to allow any "
"type to participate in the weak reference mechanism without incurring the "
"overhead on those objects which do not benefit by weak referencing (such as "
"numbers)."
msgstr ""

#: ../Doc/extending/newtypes.rst:1432
msgid ""
"For an object to be weakly referencable, the extension must include a :c:"
"type:`PyObject\\*` field in the instance structure for the use of the weak "
"reference mechanism; it must be initialized to *NULL* by the object's "
"constructor.  It must also set the :c:member:`~PyTypeObject."
"tp_weaklistoffset` field of the corresponding type object to the offset of "
"the field. For example, the instance type is defined with the following "
"structure::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1446
msgid "The statically-declared type object for instances is defined this way::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1463
msgid ""
"The type constructor is responsible for initializing the weak reference list "
"to *NULL*::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1475
msgid ""
"The only further addition is that the destructor needs to call the weak "
"reference manager to clear any weak references.  This is only required if "
"the weak reference list is non-*NULL*::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1494
msgid "More Suggestions"
msgstr ""

#: ../Doc/extending/newtypes.rst:1496
msgid ""
"Remember that you can omit most of these functions, in which case you "
"provide ``0`` as a value.  There are type definitions for each of the "
"functions you must provide.  They are in :file:`object.h` in the Python "
"include directory that comes with the source distribution of Python."
msgstr ""

#: ../Doc/extending/newtypes.rst:1501
msgid ""
"In order to learn how to implement any specific method for your new data "
"type, do the following: Download and unpack the Python source distribution.  "
"Go to the :file:`Objects` directory, then search the C source files for "
"``tp_`` plus the function you want (for example, ``tp_richcompare``).  You "
"will find examples of the function you want to implement."
msgstr ""

#: ../Doc/extending/newtypes.rst:1507
msgid ""
"When you need to verify that an object is an instance of the type you are "
"implementing, use the :c:func:`PyObject_TypeCheck` function. A sample of its "
"use might be something like the following::"
msgstr ""

#: ../Doc/extending/newtypes.rst:1517
msgid "Footnotes"
msgstr "Notes"

#: ../Doc/extending/newtypes.rst:1518
msgid ""
"This is true when we know that the object is a basic type, like a string or "
"a float."
msgstr ""

#: ../Doc/extending/newtypes.rst:1521
msgid ""
"We relied on this in the :c:member:`~PyTypeObject.tp_dealloc` handler in "
"this example, because our type doesn't support garbage collection. Even if a "
"type supports garbage collection, there are calls that can be made to "
"\"untrack\" the object from garbage collection, however, these calls are "
"advanced and not covered here."
msgstr ""

#: ../Doc/extending/newtypes.rst:1526
msgid ""
"We now know that the first and last members are strings, so perhaps we could "
"be less careful about decrementing their reference counts, however, we "
"accept instances of string subclasses. Even though deallocating normal "
"strings won't call back into our objects, we can't guarantee that "
"deallocating an instance of a string subclass won't call back into our "
"objects."
msgstr ""

#: ../Doc/extending/newtypes.rst:1532
msgid ""
"Even in the third version, we aren't guaranteed to avoid cycles.  Instances "
"of string subclasses are allowed and string subclasses could allow cycles "
"even if normal strings don't."
msgstr ""