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dataclasses.po
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# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001-2023, Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
# Translators:
# Transifex Bot <>, 2023
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Python 3.11\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2023-05-19 14:13+0000\n"
"PO-Revision-Date: 2021-06-28 01:03+0000\n"
"Last-Translator: Transifex Bot <>, 2023\n"
"Language-Team: Polish (https://app.transifex.com/python-doc/teams/5390/pl/)\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Language: pl\n"
"Plural-Forms: nplurals=4; plural=(n==1 ? 0 : (n%10>=2 && n%10<=4) && "
"(n%100<12 || n%100>14) ? 1 : n!=1 && (n%10>=0 && n%10<=1) || (n%10>=5 && "
"n%10<=9) || (n%100>=12 && n%100<=14) ? 2 : 3);\n"
msgid ":mod:`dataclasses` --- Data Classes"
msgstr ""
msgid "**Source code:** :source:`Lib/dataclasses.py`"
msgstr ""
msgid ""
"This module provides a decorator and functions for automatically adding "
"generated :term:`special method`\\s such as :meth:`~object.__init__` and :"
"meth:`~object.__repr__` to user-defined classes. It was originally "
"described in :pep:`557`."
msgstr ""
msgid ""
"The member variables to use in these generated methods are defined using :"
"pep:`526` type annotations. For example, this code::"
msgstr ""
msgid ""
"will add, among other things, a :meth:`~object.__init__` that looks like::"
msgstr ""
msgid ""
"Note that this method is automatically added to the class: it is not "
"directly specified in the ``InventoryItem`` definition shown above."
msgstr ""
msgid "Module contents"
msgstr ""
msgid ""
"This function is a :term:`decorator` that is used to add generated :term:"
"`special method`\\s to classes, as described below."
msgstr ""
msgid ""
"The :func:`dataclass` decorator examines the class to find ``field``\\s. A "
"``field`` is defined as a class variable that has a :term:`type annotation "
"<variable annotation>`. With two exceptions described below, nothing in :"
"func:`dataclass` examines the type specified in the variable annotation."
msgstr ""
msgid ""
"The order of the fields in all of the generated methods is the order in "
"which they appear in the class definition."
msgstr ""
msgid ""
"The :func:`dataclass` decorator will add various \"dunder\" methods to the "
"class, described below. If any of the added methods already exist in the "
"class, the behavior depends on the parameter, as documented below. The "
"decorator returns the same class that it is called on; no new class is "
"created."
msgstr ""
msgid ""
"If :func:`dataclass` is used just as a simple decorator with no parameters, "
"it acts as if it has the default values documented in this signature. That "
"is, these three uses of :func:`dataclass` are equivalent::"
msgstr ""
msgid "The parameters to :func:`dataclass` are:"
msgstr ""
msgid ""
"``init``: If true (the default), a :meth:`~object.__init__` method will be "
"generated."
msgstr ""
msgid ""
"If the class already defines :meth:`~object.__init__`, this parameter is "
"ignored."
msgstr ""
msgid ""
"``repr``: If true (the default), a :meth:`~object.__repr__` method will be "
"generated. The generated repr string will have the class name and the name "
"and repr of each field, in the order they are defined in the class. Fields "
"that are marked as being excluded from the repr are not included. For "
"example: ``InventoryItem(name='widget', unit_price=3.0, "
"quantity_on_hand=10)``."
msgstr ""
msgid ""
"If the class already defines :meth:`~object.__repr__`, this parameter is "
"ignored."
msgstr ""
msgid ""
"``eq``: If true (the default), an :meth:`~object.__eq__` method will be "
"generated. This method compares the class as if it were a tuple of its "
"fields, in order. Both instances in the comparison must be of the identical "
"type."
msgstr ""
msgid ""
"If the class already defines :meth:`~object.__eq__`, this parameter is "
"ignored."
msgstr ""
msgid ""
"``order``: If true (the default is ``False``), :meth:`~object.__lt__`, :meth:"
"`~object.__le__`, :meth:`~object.__gt__`, and :meth:`~object.__ge__` methods "
"will be generated. These compare the class as if it were a tuple of its "
"fields, in order. Both instances in the comparison must be of the identical "
"type. If ``order`` is true and ``eq`` is false, a :exc:`ValueError` is "
"raised."
msgstr ""
msgid ""
"If the class already defines any of :meth:`~object.__lt__`, :meth:`~object."
"__le__`, :meth:`~object.__gt__`, or :meth:`~object.__ge__`, then :exc:"
"`TypeError` is raised."
msgstr ""
msgid ""
"``unsafe_hash``: If ``False`` (the default), a :meth:`~object.__hash__` "
"method is generated according to how ``eq`` and ``frozen`` are set."
msgstr ""
msgid ""
":meth:`~object.__hash__` is used by built-in :meth:`hash()`, and when "
"objects are added to hashed collections such as dictionaries and sets. "
"Having a :meth:`~object.__hash__` implies that instances of the class are "
"immutable. Mutability is a complicated property that depends on the "
"programmer's intent, the existence and behavior of :meth:`~object.__eq__`, "
"and the values of the ``eq`` and ``frozen`` flags in the :func:`dataclass` "
"decorator."
msgstr ""
msgid ""
"By default, :func:`dataclass` will not implicitly add a :meth:`~object."
"__hash__` method unless it is safe to do so. Neither will it add or change "
"an existing explicitly defined :meth:`~object.__hash__` method. Setting the "
"class attribute ``__hash__ = None`` has a specific meaning to Python, as "
"described in the :meth:`~object.__hash__` documentation."
msgstr ""
msgid ""
"If :meth:`~object.__hash__` is not explicitly defined, or if it is set to "
"``None``, then :func:`dataclass` *may* add an implicit :meth:`~object."
"__hash__` method. Although not recommended, you can force :func:`dataclass` "
"to create a :meth:`~object.__hash__` method with ``unsafe_hash=True``. This "
"might be the case if your class is logically immutable but can nonetheless "
"be mutated. This is a specialized use case and should be considered "
"carefully."
msgstr ""
msgid ""
"Here are the rules governing implicit creation of a :meth:`~object.__hash__` "
"method. Note that you cannot both have an explicit :meth:`~object.__hash__` "
"method in your dataclass and set ``unsafe_hash=True``; this will result in "
"a :exc:`TypeError`."
msgstr ""
msgid ""
"If ``eq`` and ``frozen`` are both true, by default :func:`dataclass` will "
"generate a :meth:`~object.__hash__` method for you. If ``eq`` is true and "
"``frozen`` is false, :meth:`~object.__hash__` will be set to ``None``, "
"marking it unhashable (which it is, since it is mutable). If ``eq`` is "
"false, :meth:`~object.__hash__` will be left untouched meaning the :meth:"
"`~object.__hash__` method of the superclass will be used (if the superclass "
"is :class:`object`, this means it will fall back to id-based hashing)."
msgstr ""
msgid ""
"``frozen``: If true (the default is ``False``), assigning to fields will "
"generate an exception. This emulates read-only frozen instances. If :meth:"
"`~object.__setattr__` or :meth:`~object.__delattr__` is defined in the "
"class, then :exc:`TypeError` is raised. See the discussion below."
msgstr ""
msgid ""
"``match_args``: If true (the default is ``True``), the ``__match_args__`` "
"tuple will be created from the list of parameters to the generated :meth:"
"`~object.__init__` method (even if :meth:`~object.__init__` is not "
"generated, see above). If false, or if ``__match_args__`` is already "
"defined in the class, then ``__match_args__`` will not be generated."
msgstr ""
msgid ""
"``kw_only``: If true (the default value is ``False``), then all fields will "
"be marked as keyword-only. If a field is marked as keyword-only, then the "
"only effect is that the :meth:`~object.__init__` parameter generated from a "
"keyword-only field must be specified with a keyword when :meth:`~object."
"__init__` is called. There is no effect on any other aspect of "
"dataclasses. See the :term:`parameter` glossary entry for details. Also "
"see the :const:`KW_ONLY` section."
msgstr ""
msgid ""
"``slots``: If true (the default is ``False``), :attr:`~object.__slots__` "
"attribute will be generated and new class will be returned instead of the "
"original one. If :attr:`~object.__slots__` is already defined in the class, "
"then :exc:`TypeError` is raised."
msgstr ""
msgid ""
"If a field name is already included in the ``__slots__`` of a base class, it "
"will not be included in the generated ``__slots__`` to prevent :ref:"
"`overriding them <datamodel-note-slots>`. Therefore, do not use "
"``__slots__`` to retrieve the field names of a dataclass. Use :func:`fields` "
"instead. To be able to determine inherited slots, base class ``__slots__`` "
"may be any iterable, but *not* an iterator."
msgstr ""
msgid ""
"``weakref_slot``: If true (the default is ``False``), add a slot named "
"\"__weakref__\", which is required to make an instance weakref-able. It is "
"an error to specify ``weakref_slot=True`` without also specifying "
"``slots=True``."
msgstr ""
msgid ""
"``field``\\s may optionally specify a default value, using normal Python "
"syntax::"
msgstr ""
msgid ""
"In this example, both ``a`` and ``b`` will be included in the added :meth:"
"`~object.__init__` method, which will be defined as::"
msgstr ""
msgid ""
":exc:`TypeError` will be raised if a field without a default value follows a "
"field with a default value. This is true whether this occurs in a single "
"class, or as a result of class inheritance."
msgstr ""
msgid ""
"For common and simple use cases, no other functionality is required. There "
"are, however, some dataclass features that require additional per-field "
"information. To satisfy this need for additional information, you can "
"replace the default field value with a call to the provided :func:`field` "
"function. For example::"
msgstr ""
msgid ""
"As shown above, the :const:`MISSING` value is a sentinel object used to "
"detect if some parameters are provided by the user. This sentinel is used "
"because ``None`` is a valid value for some parameters with a distinct "
"meaning. No code should directly use the :const:`MISSING` value."
msgstr ""
msgid "The parameters to :func:`field` are:"
msgstr ""
msgid ""
"``default``: If provided, this will be the default value for this field. "
"This is needed because the :meth:`field` call itself replaces the normal "
"position of the default value."
msgstr ""
msgid ""
"``default_factory``: If provided, it must be a zero-argument callable that "
"will be called when a default value is needed for this field. Among other "
"purposes, this can be used to specify fields with mutable default values, as "
"discussed below. It is an error to specify both ``default`` and "
"``default_factory``."
msgstr ""
msgid ""
"``init``: If true (the default), this field is included as a parameter to "
"the generated :meth:`~object.__init__` method."
msgstr ""
msgid ""
"``repr``: If true (the default), this field is included in the string "
"returned by the generated :meth:`~object.__repr__` method."
msgstr ""
msgid ""
"``hash``: This can be a bool or ``None``. If true, this field is included "
"in the generated :meth:`~object.__hash__` method. If ``None`` (the "
"default), use the value of ``compare``: this would normally be the expected "
"behavior. A field should be considered in the hash if it's used for "
"comparisons. Setting this value to anything other than ``None`` is "
"discouraged."
msgstr ""
msgid ""
"One possible reason to set ``hash=False`` but ``compare=True`` would be if a "
"field is expensive to compute a hash value for, that field is needed for "
"equality testing, and there are other fields that contribute to the type's "
"hash value. Even if a field is excluded from the hash, it will still be "
"used for comparisons."
msgstr ""
msgid ""
"``compare``: If true (the default), this field is included in the generated "
"equality and comparison methods (:meth:`~object.__eq__`, :meth:`~object."
"__gt__`, et al.)."
msgstr ""
msgid ""
"``metadata``: This can be a mapping or None. None is treated as an empty "
"dict. This value is wrapped in :func:`~types.MappingProxyType` to make it "
"read-only, and exposed on the :class:`Field` object. It is not used at all "
"by Data Classes, and is provided as a third-party extension mechanism. "
"Multiple third-parties can each have their own key, to use as a namespace in "
"the metadata."
msgstr ""
msgid ""
"``kw_only``: If true, this field will be marked as keyword-only. This is "
"used when the generated :meth:`~object.__init__` method's parameters are "
"computed."
msgstr ""
msgid ""
"If the default value of a field is specified by a call to :func:`field()`, "
"then the class attribute for this field will be replaced by the specified "
"``default`` value. If no ``default`` is provided, then the class attribute "
"will be deleted. The intent is that after the :func:`dataclass` decorator "
"runs, the class attributes will all contain the default values for the "
"fields, just as if the default value itself were specified. For example, "
"after::"
msgstr ""
msgid ""
"The class attribute ``C.z`` will be ``10``, the class attribute ``C.t`` will "
"be ``20``, and the class attributes ``C.x`` and ``C.y`` will not be set."
msgstr ""
msgid ""
":class:`Field` objects describe each defined field. These objects are "
"created internally, and are returned by the :func:`fields` module-level "
"method (see below). Users should never instantiate a :class:`Field` object "
"directly. Its documented attributes are:"
msgstr ""
msgid "``name``: The name of the field."
msgstr ""
msgid "``type``: The type of the field."
msgstr ""
msgid ""
"``default``, ``default_factory``, ``init``, ``repr``, ``hash``, ``compare``, "
"``metadata``, and ``kw_only`` have the identical meaning and values as they "
"do in the :func:`field` function."
msgstr ""
msgid ""
"Other attributes may exist, but they are private and must not be inspected "
"or relied on."
msgstr ""
msgid ""
"Returns a tuple of :class:`Field` objects that define the fields for this "
"dataclass. Accepts either a dataclass, or an instance of a dataclass. "
"Raises :exc:`TypeError` if not passed a dataclass or instance of one. Does "
"not return pseudo-fields which are ``ClassVar`` or ``InitVar``."
msgstr ""
msgid ""
"Converts the dataclass ``obj`` to a dict (by using the factory function "
"``dict_factory``). Each dataclass is converted to a dict of its fields, as "
"``name: value`` pairs. dataclasses, dicts, lists, and tuples are recursed "
"into. Other objects are copied with :func:`copy.deepcopy`."
msgstr ""
msgid "Example of using :func:`asdict` on nested dataclasses::"
msgstr ""
msgid "To create a shallow copy, the following workaround may be used::"
msgstr ""
msgid ""
":func:`asdict` raises :exc:`TypeError` if ``obj`` is not a dataclass "
"instance."
msgstr ""
msgid ""
"Converts the dataclass ``obj`` to a tuple (by using the factory function "
"``tuple_factory``). Each dataclass is converted to a tuple of its field "
"values. dataclasses, dicts, lists, and tuples are recursed into. Other "
"objects are copied with :func:`copy.deepcopy`."
msgstr ""
msgid "Continuing from the previous example::"
msgstr ""
msgid ""
":func:`astuple` raises :exc:`TypeError` if ``obj`` is not a dataclass "
"instance."
msgstr ""
msgid ""
"Creates a new dataclass with name ``cls_name``, fields as defined in "
"``fields``, base classes as given in ``bases``, and initialized with a "
"namespace as given in ``namespace``. ``fields`` is an iterable whose "
"elements are each either ``name``, ``(name, type)``, or ``(name, type, "
"Field)``. If just ``name`` is supplied, ``typing.Any`` is used for "
"``type``. The values of ``init``, ``repr``, ``eq``, ``order``, "
"``unsafe_hash``, ``frozen``, ``match_args``, ``kw_only``, ``slots``, and "
"``weakref_slot`` have the same meaning as they do in :func:`dataclass`."
msgstr ""
msgid ""
"This function is not strictly required, because any Python mechanism for "
"creating a new class with ``__annotations__`` can then apply the :func:"
"`dataclass` function to convert that class to a dataclass. This function is "
"provided as a convenience. For example::"
msgstr ""
msgid "Is equivalent to::"
msgstr ""
msgid ""
"Creates a new object of the same type as ``obj``, replacing fields with "
"values from ``changes``. If ``obj`` is not a Data Class, raises :exc:"
"`TypeError`. If values in ``changes`` do not specify fields, raises :exc:"
"`TypeError`."
msgstr ""
msgid ""
"The newly returned object is created by calling the :meth:`~object.__init__` "
"method of the dataclass. This ensures that :ref:`__post_init__ <post-init-"
"processing>`, if present, is also called."
msgstr ""
msgid ""
"Init-only variables without default values, if any exist, must be specified "
"on the call to :func:`replace` so that they can be passed to :meth:`~object."
"__init__` and :ref:`__post_init__ <post-init-processing>`."
msgstr ""
msgid ""
"It is an error for ``changes`` to contain any fields that are defined as "
"having ``init=False``. A :exc:`ValueError` will be raised in this case."
msgstr ""
msgid ""
"Be forewarned about how ``init=False`` fields work during a call to :func:"
"`replace`. They are not copied from the source object, but rather are "
"initialized in :ref:`__post_init__ <post-init-processing>`, if they're "
"initialized at all. It is expected that ``init=False`` fields will be "
"rarely and judiciously used. If they are used, it might be wise to have "
"alternate class constructors, or perhaps a custom ``replace()`` (or "
"similarly named) method which handles instance copying."
msgstr ""
msgid ""
"Return ``True`` if its parameter is a dataclass or an instance of one, "
"otherwise return ``False``."
msgstr ""
msgid ""
"If you need to know if a class is an instance of a dataclass (and not a "
"dataclass itself), then add a further check for ``not isinstance(obj, "
"type)``::"
msgstr ""
msgid "A sentinel value signifying a missing default or default_factory."
msgstr ""
msgid ""
"A sentinel value used as a type annotation. Any fields after a pseudo-field "
"with the type of :const:`KW_ONLY` are marked as keyword-only fields. Note "
"that a pseudo-field of type :const:`KW_ONLY` is otherwise completely "
"ignored. This includes the name of such a field. By convention, a name of "
"``_`` is used for a :const:`KW_ONLY` field. Keyword-only fields signify :"
"meth:`~object.__init__` parameters that must be specified as keywords when "
"the class is instantiated."
msgstr ""
msgid ""
"In this example, the fields ``y`` and ``z`` will be marked as keyword-only "
"fields::"
msgstr ""
msgid ""
"In a single dataclass, it is an error to specify more than one field whose "
"type is :const:`KW_ONLY`."
msgstr ""
msgid ""
"Raised when an implicitly defined :meth:`~object.__setattr__` or :meth:"
"`~object.__delattr__` is called on a dataclass which was defined with "
"``frozen=True``. It is a subclass of :exc:`AttributeError`."
msgstr ""
msgid "Post-init processing"
msgstr ""
msgid ""
"The generated :meth:`~object.__init__` code will call a method named :meth:`!"
"__post_init__`, if :meth:`!__post_init__` is defined on the class. It will "
"normally be called as ``self.__post_init__()``. However, if any ``InitVar`` "
"fields are defined, they will also be passed to :meth:`!__post_init__` in "
"the order they were defined in the class. If no :meth:`~object.__init__` "
"method is generated, then :meth:`!__post_init__` will not automatically be "
"called."
msgstr ""
msgid ""
"Among other uses, this allows for initializing field values that depend on "
"one or more other fields. For example::"
msgstr ""
msgid ""
"The :meth:`~object.__init__` method generated by :func:`dataclass` does not "
"call base class :meth:`~object.__init__` methods. If the base class has an :"
"meth:`~object.__init__` method that has to be called, it is common to call "
"this method in a :meth:`!__post_init__` method::"
msgstr ""
msgid ""
"Note, however, that in general the dataclass-generated :meth:`~object."
"__init__` methods don't need to be called, since the derived dataclass will "
"take care of initializing all fields of any base class that is a dataclass "
"itself."
msgstr ""
msgid ""
"See the section below on init-only variables for ways to pass parameters to :"
"meth:`!__post_init__`. Also see the warning about how :func:`replace` "
"handles ``init=False`` fields."
msgstr ""
msgid "Class variables"
msgstr ""
msgid ""
"One of the few places where :func:`dataclass` actually inspects the type of "
"a field is to determine if a field is a class variable as defined in :pep:"
"`526`. It does this by checking if the type of the field is ``typing."
"ClassVar``. If a field is a ``ClassVar``, it is excluded from consideration "
"as a field and is ignored by the dataclass mechanisms. Such ``ClassVar`` "
"pseudo-fields are not returned by the module-level :func:`fields` function."
msgstr ""
msgid "Init-only variables"
msgstr ""
msgid ""
"Another place where :func:`dataclass` inspects a type annotation is to "
"determine if a field is an init-only variable. It does this by seeing if "
"the type of a field is of type ``dataclasses.InitVar``. If a field is an "
"``InitVar``, it is considered a pseudo-field called an init-only field. As "
"it is not a true field, it is not returned by the module-level :func:"
"`fields` function. Init-only fields are added as parameters to the "
"generated :meth:`~object.__init__` method, and are passed to the optional :"
"ref:`__post_init__ <post-init-processing>` method. They are not otherwise "
"used by dataclasses."
msgstr ""
msgid ""
"For example, suppose a field will be initialized from a database, if a value "
"is not provided when creating the class::"
msgstr ""
msgid ""
"In this case, :func:`fields` will return :class:`Field` objects for ``i`` "
"and ``j``, but not for ``database``."
msgstr ""
msgid "Frozen instances"
msgstr ""
msgid ""
"It is not possible to create truly immutable Python objects. However, by "
"passing ``frozen=True`` to the :meth:`dataclass` decorator you can emulate "
"immutability. In that case, dataclasses will add :meth:`~object."
"__setattr__` and :meth:`~object.__delattr__` methods to the class. These "
"methods will raise a :exc:`FrozenInstanceError` when invoked."
msgstr ""
msgid ""
"There is a tiny performance penalty when using ``frozen=True``: :meth:"
"`~object.__init__` cannot use simple assignment to initialize fields, and "
"must use :meth:`~object.__setattr__`."
msgstr ""
msgid "Inheritance"
msgstr ""
msgid ""
"When the dataclass is being created by the :meth:`dataclass` decorator, it "
"looks through all of the class's base classes in reverse MRO (that is, "
"starting at :class:`object`) and, for each dataclass that it finds, adds the "
"fields from that base class to an ordered mapping of fields. After all of "
"the base class fields are added, it adds its own fields to the ordered "
"mapping. All of the generated methods will use this combined, calculated "
"ordered mapping of fields. Because the fields are in insertion order, "
"derived classes override base classes. An example::"
msgstr ""
msgid ""
"The final list of fields is, in order, ``x``, ``y``, ``z``. The final type "
"of ``x`` is ``int``, as specified in class ``C``."
msgstr ""
msgid ""
"The generated :meth:`~object.__init__` method for ``C`` will look like::"
msgstr ""
msgid "Re-ordering of keyword-only parameters in :meth:`~object.__init__`"
msgstr ""
msgid ""
"After the parameters needed for :meth:`~object.__init__` are computed, any "
"keyword-only parameters are moved to come after all regular (non-keyword-"
"only) parameters. This is a requirement of how keyword-only parameters are "
"implemented in Python: they must come after non-keyword-only parameters."
msgstr ""
msgid ""
"In this example, ``Base.y``, ``Base.w``, and ``D.t`` are keyword-only "
"fields, and ``Base.x`` and ``D.z`` are regular fields::"
msgstr ""
msgid ""
"The generated :meth:`~object.__init__` method for ``D`` will look like::"
msgstr ""
msgid ""
"Note that the parameters have been re-ordered from how they appear in the "
"list of fields: parameters derived from regular fields are followed by "
"parameters derived from keyword-only fields."
msgstr ""
msgid ""
"The relative ordering of keyword-only parameters is maintained in the re-"
"ordered :meth:`~object.__init__` parameter list."
msgstr ""
msgid "Default factory functions"
msgstr ""
msgid ""
"If a :func:`field` specifies a ``default_factory``, it is called with zero "
"arguments when a default value for the field is needed. For example, to "
"create a new instance of a list, use::"
msgstr ""
msgid ""
"If a field is excluded from :meth:`~object.__init__` (using ``init=False``) "
"and the field also specifies ``default_factory``, then the default factory "
"function will always be called from the generated :meth:`~object.__init__` "
"function. This happens because there is no other way to give the field an "
"initial value."
msgstr ""
msgid "Mutable default values"
msgstr ""
msgid ""
"Python stores default member variable values in class attributes. Consider "
"this example, not using dataclasses::"
msgstr ""
msgid ""
"Note that the two instances of class ``C`` share the same class variable "
"``x``, as expected."
msgstr ""
msgid "Using dataclasses, *if* this code was valid::"
msgstr ""
msgid "it would generate code similar to::"
msgstr ""
msgid ""
"This has the same issue as the original example using class ``C``. That is, "
"two instances of class ``D`` that do not specify a value for ``x`` when "
"creating a class instance will share the same copy of ``x``. Because "
"dataclasses just use normal Python class creation they also share this "
"behavior. There is no general way for Data Classes to detect this "
"condition. Instead, the :func:`dataclass` decorator will raise a :exc:"
"`TypeError` if it detects an unhashable default parameter. The assumption "
"is that if a value is unhashable, it is mutable. This is a partial "
"solution, but it does protect against many common errors."
msgstr ""
msgid ""
"Using default factory functions is a way to create new instances of mutable "
"types as default values for fields::"
msgstr ""
msgid ""
"Instead of looking for and disallowing objects of type ``list``, ``dict``, "
"or ``set``, unhashable objects are now not allowed as default values. "
"Unhashability is used to approximate mutability."
msgstr ""
msgid "Descriptor-typed fields"
msgstr ""
msgid ""
"Fields that are assigned :ref:`descriptor objects <descriptors>` as their "
"default value have the following special behaviors:"
msgstr ""
msgid ""
"The value for the field passed to the dataclass's ``__init__`` method is "
"passed to the descriptor's ``__set__`` method rather than overwriting the "
"descriptor object."
msgstr ""
msgid ""
"Similarly, when getting or setting the field, the descriptor's ``__get__`` "
"or ``__set__`` method is called rather than returning or overwriting the "
"descriptor object."
msgstr ""
msgid ""
"To determine whether a field contains a default value, ``dataclasses`` will "
"call the descriptor's ``__get__`` method using its class access form (i.e. "
"``descriptor.__get__(obj=None, type=cls)``. If the descriptor returns a "
"value in this case, it will be used as the field's default. On the other "
"hand, if the descriptor raises :exc:`AttributeError` in this situation, no "
"default value will be provided for the field."
msgstr ""
msgid ""
"Note that if a field is annotated with a descriptor type, but is not "
"assigned a descriptor object as its default value, the field will act like a "
"normal field."
msgstr ""