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# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001-2021, Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
# Translators:
# Maciej Olko <maciej.olko@gmail.com>, 2019
# Tomasz Rodzen <t.rodzen@poczta.fm>, 2020
# Igor Zubrycki <igorzubrycki@gmail.com>, 2020
"Project-Id-Version: Python 3.9\n"
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"Last-Translator: Igor Zubrycki <igorzubrycki@gmail.com>, 2020\n"
"Language-Team: Polish (https://www.transifex.com/python-doc/teams/5390/pl/)\n"
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msgid "Classes"
msgstr "Klasy"
"Classes provide a means of bundling data and functionality together.  "
"Creating a new class creates a new *type* of object, allowing new "
"*instances* of that type to be made.  Each class instance can have "
"attributes attached to it for maintaining its state.  Class instances can "
"also have methods (defined by its class) for modifying its state."
"Klasy dostarczają sposoby powiązania informacji i funkcjonalności. "
"Stworzenie nowej klasy, tworzy nowy typ obiektu, pozwalający na tworzenie "
"nowych instancji tego typu. Każda instancja klasy może mieć atrybuty "
"przypisane w celu utrzymania jej stanu. Instancje klas mogą również posiadać "
"metody (zdefiniowane przez jej klasę) w celu modyfikacje ich stanu."
"Compared with other programming languages, Python's class mechanism adds "
"classes with a minimum of new syntax and semantics.  It is a mixture of the "
"class mechanisms found in C++ and Modula-3.  Python classes provide all the "
"standard features of Object Oriented Programming: the class inheritance "
"mechanism allows multiple base classes, a derived class can override any "
"methods of its base class or classes, and a method can call the method of a "
"base class with the same name.  Objects can contain arbitrary amounts and "
"kinds of data.  As is true for modules, classes partake of the dynamic "
"nature of Python: they are created at runtime, and can be modified further "
"after creation."
"W porównaniu do innych języków programowania, w Pythonie, mechanizm "
"dodawania nowych klas wymaga niewielkiej ilości nowej składni i semantyki. "
"Jest to połączenie  mechanizmu klas, które można znaleźć w C++ i Modula-3. "
"Klasy w Pythonie dostarczają wszystkie standardowe cechy Programowania "
"Obiektowego: mechanizm dziedziczenia klas pozwala na tworzenie wielu "
"bazowych klas, pochodne klasy mogą nadpisać każdą metodę klasy lub klas "
"bazowej i metoda może przywołać metody klas bazowych o tej samej nazwie. "
"Obiekty mogą zawierać dowolną ilość i rodzaj danych. Zarówno klasy jak i "
"moduły są częścią dynamicznej natury Python'a: są tworzone w trakcje "
"działania programu i mogą być modyfikowane później, po stworzeniu. "
"In C++ terminology, normally class members (including the data members) are "
"*public* (except see below :ref:`tut-private`), and all member functions are "
"*virtual*.  As in Modula-3, there are no shorthands for referencing the "
"object's members from its methods: the method function is declared with an "
"explicit first argument representing the object, which is provided "
"implicitly by the call.  As in Smalltalk, classes themselves are objects.  "
"This provides semantics for importing and renaming.  Unlike C++ and "
"Modula-3, built-in types can be used as base classes for extension by the "
"user.  Also, like in C++, most built-in operators with special syntax "
"(arithmetic operators, subscripting etc.) can be redefined for class "
"instances."
"Korzystając z terminologii C++, składniki klas (także pola)są *publiczne* (z "
"wyjątkiem zobacz :ref:`tut-private`), a wszystkie metody są *wirtualne*.  "
"Podobnie jak w Moduli-3, nie ma skrótów pozwalających na odnoszenie się do "
"składników klas z ich metod: metoda jest deklarowana poprzez podanie wprost "
"jako pierwszego argumentu obiektu, który w czasie wywołania metody zostanie "
"jej przekazany niejawnie. Podobnie jak w Smalltalku, same klasy także są "
"obiektami.  Dostarcza nam to wyrażeń semantycznych pozwalających na "
"importowanie i zmianę nazw klasy. Inaczej niż w C++ i Moduli-3 wbudowane "
"typy mogą stanowić klasy z których klasa użytkownika będzie dziedziczyć. "
"Podobnie jak w C++, większość wbudowanych operatorów ze specjalną składnią "
"(operatory arytmetyczne, indeksowanie) mogą być przedefiniowane przez "
"instancje klasy."
"(Lacking universally accepted terminology to talk about classes, I will make "
"occasional use of Smalltalk and C++ terms.  I would use Modula-3 terms, "
"since its object-oriented semantics are closer to those of Python than C++, "
"but I expect that few readers have heard of it.)"
"(Z powodu braku ogólnie zaakceptowanej terminologii w kontekście klas, będę "
"używał terminów ze Samlltalk i C++. Użyłbym Modula-3 ponieważ semantyka "
"programowania obiektowego jest mu bliższa Pythonowi niż C++ ale zakładam, że "
"mniej czytelników o nim słyszało.)"
msgid "A Word About Names and Objects"
msgstr "Kilka słów o nazwach i obiektach"
"Objects have individuality, and multiple names (in multiple scopes) can be "
"bound to the same object.  This is known as aliasing in other languages.  "
"This is usually not appreciated on a first glance at Python, and can be "
"safely ignored when dealing with immutable basic types (numbers, strings, "
"tuples).  However, aliasing has a possibly surprising effect on the "
"semantics of Python code involving mutable objects such as lists, "
"dictionaries, and most other types. This is usually used to the benefit of "
"the program, since aliases behave like pointers in some respects.  For "
"example, passing an object is cheap since only a pointer is passed by the "
"implementation; and if a function modifies an object passed as an argument, "
"the caller will see the change --- this eliminates the need for two "
"different argument passing mechanisms as in Pascal."
msgid "Python Scopes and Namespaces"
"Before introducing classes, I first have to tell you something about "
"Python's scope rules.  Class definitions play some neat tricks with "
"namespaces, and you need to know how scopes and namespaces work to fully "
"understand what's going on. Incidentally, knowledge about this subject is "
"useful for any advanced Python programmer."
msgid "Let's begin with some definitions."
"A *namespace* is a mapping from names to objects.  Most namespaces are "
"currently implemented as Python dictionaries, but that's normally not "
"noticeable in any way (except for performance), and it may change in the "
"future.  Examples of namespaces are: the set of built-in names (containing "
"functions such as :func:`abs`, and built-in exception names); the global "
"names in a module; and the local names in a function invocation.  In a sense "
"the set of attributes of an object also form a namespace.  The important "
"thing to know about namespaces is that there is absolutely no relation "
"between names in different namespaces; for instance, two different modules "
"may both define a function ``maximize`` without confusion --- users of the "
"modules must prefix it with the module name."
"By the way, I use the word *attribute* for any name following a dot --- for "
"example, in the expression ``z.real``, ``real`` is an attribute of the "
"object ``z``.  Strictly speaking, references to names in modules are "
"attribute references: in the expression ``modname.funcname``, ``modname`` is "
"a module object and ``funcname`` is an attribute of it.  In this case there "
"happens to be a straightforward mapping between the module's attributes and "
"the global names defined in the module: they share the same namespace!  [#]_"
"Attributes may be read-only or writable.  In the latter case, assignment to "
"attributes is possible.  Module attributes are writable: you can write "
"``modname.the_answer = 42``.  Writable attributes may also be deleted with "
"the :keyword:`del` statement.  For example, ``del modname.the_answer`` will "
"remove the attribute :attr:`the_answer` from the object named by ``modname``."
"Namespaces are created at different moments and have different lifetimes.  "
"The namespace containing the built-in names is created when the Python "
"interpreter starts up, and is never deleted.  The global namespace for a "
"module is created when the module definition is read in; normally, module "
"namespaces also last until the interpreter quits.  The statements executed "
"by the top-level invocation of the interpreter, either read from a script "
"file or interactively, are considered part of a module called :mod:"
"`__main__`, so they have their own global namespace.  (The built-in names "
"actually also live in a module; this is called :mod:`builtins`.)"
"The local namespace for a function is created when the function is called, "
"and deleted when the function returns or raises an exception that is not "
"handled within the function.  (Actually, forgetting would be a better way to "
"describe what actually happens.)  Of course, recursive invocations each have "
"their own local namespace."
"A *scope* is a textual region of a Python program where a namespace is "
"directly accessible.  \"Directly accessible\" here means that an unqualified "
"reference to a name attempts to find the name in the namespace."
"Although scopes are determined statically, they are used dynamically. At any "
"time during execution, there are 3 or 4 nested scopes whose namespaces are "
"directly accessible:"
msgid "the innermost scope, which is searched first, contains the local names"
"the scopes of any enclosing functions, which are searched starting with the "
"nearest enclosing scope, contains non-local, but also non-global names"
msgid "the next-to-last scope contains the current module's global names"
"the outermost scope (searched last) is the namespace containing built-in "
"If a name is declared global, then all references and assignments go "
"directly to the middle scope containing the module's global names.  To "
"rebind variables found outside of the innermost scope, the :keyword:"
"`nonlocal` statement can be used; if not declared nonlocal, those variables "
"are read-only (an attempt to write to such a variable will simply create a "
"*new* local variable in the innermost scope, leaving the identically named "
"outer variable unchanged)."
"Usually, the local scope references the local names of the (textually) "
"current function.  Outside functions, the local scope references the same "
"namespace as the global scope: the module's namespace. Class definitions "
"place yet another namespace in the local scope."
"It is important to realize that scopes are determined textually: the global "
"scope of a function defined in a module is that module's namespace, no "
"matter from where or by what alias the function is called.  On the other "
"hand, the actual search for names is done dynamically, at run time --- "
"however, the language definition is evolving towards static name resolution, "
"at \"compile\" time, so don't rely on dynamic name resolution!  (In fact, "
"local variables are already determined statically.)"
"A special quirk of Python is that -- if no :keyword:`global` or :keyword:"
"`nonlocal` statement is in effect -- assignments to names always go into the "
"innermost scope. Assignments do not copy data --- they just bind names to "
"objects.  The same is true for deletions: the statement ``del x`` removes "
"the binding of ``x`` from the namespace referenced by the local scope.  In "
"fact, all operations that introduce new names use the local scope: in "
"particular, :keyword:`import` statements and function definitions bind the "
"module or function name in the local scope."
"The :keyword:`global` statement can be used to indicate that particular "
"variables live in the global scope and should be rebound there; the :keyword:"
"`nonlocal` statement indicates that particular variables live in an "
"enclosing scope and should be rebound there."
msgid "Scopes and Namespaces Example"
"This is an example demonstrating how to reference the different scopes and "
"namespaces, and how :keyword:`global` and :keyword:`nonlocal` affect "
"variable binding::"
msgid "The output of the example code is:"
"Note how the *local* assignment (which is default) didn't change "
"*scope_test*\\'s binding of *spam*.  The :keyword:`nonlocal` assignment "
"changed *scope_test*\\'s binding of *spam*, and the :keyword:`global` "
"assignment changed the module-level binding."
"You can also see that there was no previous binding for *spam* before the :"
"keyword:`global` assignment."
msgid "A First Look at Classes"
"Classes introduce a little bit of new syntax, three new object types, and "
"some new semantics."
msgid "Class Definition Syntax"
msgid "The simplest form of class definition looks like this::"
"Class definitions, like function definitions (:keyword:`def` statements) "
"must be executed before they have any effect.  (You could conceivably place "
"a class definition in a branch of an :keyword:`if` statement, or inside a "
"function.)"
"In practice, the statements inside a class definition will usually be "
"function definitions, but other statements are allowed, and sometimes useful "
"--- we'll come back to this later.  The function definitions inside a class "
"normally have a peculiar form of argument list, dictated by the calling "
"conventions for methods --- again, this is explained later."
"When a class definition is entered, a new namespace is created, and used as "
"the local scope --- thus, all assignments to local variables go into this "
"new namespace.  In particular, function definitions bind the name of the new "
"function here."
"When a class definition is left normally (via the end), a *class object* is "
"created.  This is basically a wrapper around the contents of the namespace "
"created by the class definition; we'll learn more about class objects in the "
"next section.  The original local scope (the one in effect just before the "
"class definition was entered) is reinstated, and the class object is bound "
"here to the class name given in the class definition header (:class:"
"`ClassName` in the example)."
msgid "Class Objects"
"Class objects support two kinds of operations: attribute references and "
"instantiation."
"*Attribute references* use the standard syntax used for all attribute "
"references in Python: ``obj.name``.  Valid attribute names are all the names "
"that were in the class's namespace when the class object was created.  So, "
"if the class definition looked like this::"
"then ``MyClass.i`` and ``MyClass.f`` are valid attribute references, "
"returning an integer and a function object, respectively. Class attributes "
"can also be assigned to, so you can change the value of ``MyClass.i`` by "
"assignment. :attr:`__doc__` is also a valid attribute, returning the "
"docstring belonging to the class: ``\"A simple example class\"``."
"Class *instantiation* uses function notation.  Just pretend that the class "
"object is a parameterless function that returns a new instance of the class. "
"For example (assuming the above class)::"
"creates a new *instance* of the class and assigns this object to the local "
"variable ``x``."
"The instantiation operation (\"calling\" a class object) creates an empty "
"object. Many classes like to create objects with instances customized to a "
"specific initial state. Therefore a class may define a special method named :"
"meth:`__init__`, like this::"
"When a class defines an :meth:`__init__` method, class instantiation "
"automatically invokes :meth:`__init__` for the newly-created class "
"instance.  So in this example, a new, initialized instance can be obtained "
"Of course, the :meth:`__init__` method may have arguments for greater "
"flexibility.  In that case, arguments given to the class instantiation "
"operator are passed on to :meth:`__init__`.  For example, ::"
msgid "Instance Objects"
"Now what can we do with instance objects?  The only operations understood by "
"instance objects are attribute references.  There are two kinds of valid "
"attribute names: data attributes and methods."
"*data attributes* correspond to \"instance variables\" in Smalltalk, and to "
"\"data members\" in C++.  Data attributes need not be declared; like local "
"variables, they spring into existence when they are first assigned to.  For "
"example, if ``x`` is the instance of :class:`MyClass` created above, the "
"following piece of code will print the value ``16``, without leaving a "
"The other kind of instance attribute reference is a *method*. A method is a "
"function that \"belongs to\" an object.  (In Python, the term method is not "
"unique to class instances: other object types can have methods as well.  For "
"example, list objects have methods called append, insert, remove, sort, and "
"so on. However, in the following discussion, we'll use the term method "
"exclusively to mean methods of class instance objects, unless explicitly "
"stated otherwise.)"
"Valid method names of an instance object depend on its class.  By "
"definition, all attributes of a class that are function  objects define "
"corresponding methods of its instances.  So in our example, ``x.f`` is a "
"valid method reference, since ``MyClass.f`` is a function, but ``x.i`` is "
"not, since ``MyClass.i`` is not.  But ``x.f`` is not the same thing as "
"``MyClass.f`` --- it is a *method object*, not a function object."
msgid "Method Objects"
msgid "Usually, a method is called right after it is bound::"
"In the :class:`MyClass` example, this will return the string ``'hello "
"world'``. However, it is not necessary to call a method right away: ``x.f`` "
"is a method object, and can be stored away and called at a later time.  For "
"example::"
msgid "will continue to print ``hello world`` until the end of time."
"What exactly happens when a method is called?  You may have noticed that ``x."
"f()`` was called without an argument above, even though the function "
"definition for :meth:`f` specified an argument.  What happened to the "
"argument? Surely Python raises an exception when a function that requires an "
"argument is called without any --- even if the argument isn't actually "
"Actually, you may have guessed the answer: the special thing about methods "
"is that the instance object is passed as the first argument of the "
"function.  In our example, the call ``x.f()`` is exactly equivalent to "
"``MyClass.f(x)``.  In general, calling a method with a list of *n* arguments "
"is equivalent to calling the corresponding function with an argument list "
"that is created by inserting the method's instance object before the first "
"argument."
"If you still don't understand how methods work, a look at the implementation "
"can perhaps clarify matters.  When a non-data attribute of an instance is "
"referenced, the instance's class is searched.  If the name denotes a valid "
"class attribute that is a function object, a method object is created by "
"packing (pointers to) the instance object and the function object just found "
"together in an abstract object: this is the method object.  When the method "
"object is called with an argument list, a new argument list is constructed "
"from the instance object and the argument list, and the function object is "
"called with this new argument list."
msgid "Class and Instance Variables"
"Generally speaking, instance variables are for data unique to each instance "
"and class variables are for attributes and methods shared by all instances "
"of the class::"
"As discussed in :ref:`tut-object`, shared data can have possibly surprising "
"effects with involving :term:`mutable` objects such as lists and "
"dictionaries. For example, the *tricks* list in the following code should "
"not be used as a class variable because just a single list would be shared "
"by all *Dog* instances::"
msgid "Correct design of the class should use an instance variable instead::"
msgid "Random Remarks"
"If the same attribute name occurs in both an instance and in a class, then "
"attribute lookup prioritizes the instance::"
"Data attributes may be referenced by methods as well as by ordinary users "
"(\"clients\") of an object.  In other words, classes are not usable to "
"implement pure abstract data types.  In fact, nothing in Python makes it "
"possible to enforce data hiding --- it is all based upon convention.  (On "
"the other hand, the Python implementation, written in C, can completely hide "
"implementation details and control access to an object if necessary; this "
"can be used by extensions to Python written in C.)"
"Clients should use data attributes with care --- clients may mess up "
"invariants maintained by the methods by stamping on their data attributes.  "
"Note that clients may add data attributes of their own to an instance object "
"without affecting the validity of the methods, as long as name conflicts are "
"avoided --- again, a naming convention can save a lot of headaches here."
"There is no shorthand for referencing data attributes (or other methods!) "
"from within methods.  I find that this actually increases the readability of "
"methods: there is no chance of confusing local variables and instance "
"variables when glancing through a method."
"Often, the first argument of a method is called ``self``.  This is nothing "
"more than a convention: the name ``self`` has absolutely no special meaning "
"to Python.  Note, however, that by not following the convention your code "
"may be less readable to other Python programmers, and it is also conceivable "
"that a *class browser* program might be written that relies upon such a "
"convention."
"Any function object that is a class attribute defines a method for instances "
"of that class.  It is not necessary that the function definition is "
"textually enclosed in the class definition: assigning a function object to a "
"local variable in the class is also ok.  For example::"
"Now ``f``, ``g`` and ``h`` are all attributes of class :class:`C` that refer "
"to function objects, and consequently they are all methods of instances of :"
"class:`C` --- ``h`` being exactly equivalent to ``g``.  Note that this "
"practice usually only serves to confuse the reader of a program."
"Methods may call other methods by using method attributes of the ``self`` "
"argument::"
"Methods may reference global names in the same way as ordinary functions.  "
"The global scope associated with a method is the module containing its "
"definition.  (A class is never used as a global scope.)  While one rarely "
"encounters a good reason for using global data in a method, there are many "
"legitimate uses of the global scope: for one thing, functions and modules "
"imported into the global scope can be used by methods, as well as functions "
"and classes defined in it.  Usually, the class containing the method is "
"itself defined in this global scope, and in the next section we'll find some "
"good reasons why a method would want to reference its own class."
"Each value is an object, and therefore has a *class* (also called its "
"*type*). It is stored as ``object.__class__``."
msgid "Inheritance"
"Of course, a language feature would not be worthy of the name \"class\" "
"without supporting inheritance.  The syntax for a derived class definition "
"looks like this::"
"The name :class:`BaseClassName` must be defined in a scope containing the "
"derived class definition.  In place of a base class name, other arbitrary "
"expressions are also allowed.  This can be useful, for example, when the "
"base class is defined in another module::"
"Execution of a derived class definition proceeds the same as for a base "
"class. When the class object is constructed, the base class is remembered.  "
"This is used for resolving attribute references: if a requested attribute is "
"not found in the class, the search proceeds to look in the base class.  This "
"rule is applied recursively if the base class itself is derived from some "
"other class."
"There's nothing special about instantiation of derived classes: "
"``DerivedClassName()`` creates a new instance of the class.  Method "
"references are resolved as follows: the corresponding class attribute is "
"searched, descending down the chain of base classes if necessary, and the "
"method reference is valid if this yields a function object."
"Derived classes may override methods of their base classes.  Because methods "
"have no special privileges when calling other methods of the same object, a "
"method of a base class that calls another method defined in the same base "
"class may end up calling a method of a derived class that overrides it.  "
"(For C++ programmers: all methods in Python are effectively ``virtual``.)"
"An overriding method in a derived class may in fact want to extend rather "
"than simply replace the base class method of the same name. There is a "
"simple way to call the base class method directly: just call ``BaseClassName."
"methodname(self, arguments)``.  This is occasionally useful to clients as "
"well.  (Note that this only works if the base class is accessible as "
"``BaseClassName`` in the global scope.)"
msgid "Python has two built-in functions that work with inheritance:"
"Use :func:`isinstance` to check an instance's type: ``isinstance(obj, int)`` "
"will be ``True`` only if ``obj.__class__`` is :class:`int` or some class "
"derived from :class:`int`."
"Use :func:`issubclass` to check class inheritance: ``issubclass(bool, int)`` "
"is ``True`` since :class:`bool` is a subclass of :class:`int`.  However, "
"``issubclass(float, int)`` is ``False`` since :class:`float` is not a "
"subclass of :class:`int`."
msgid "Multiple Inheritance"
"Python supports a form of multiple inheritance as well.  A class definition "
"with multiple base classes looks like this::"
"For most purposes, in the simplest cases, you can think of the search for "
"attributes inherited from a parent class as depth-first, left-to-right, not "
"searching twice in the same class where there is an overlap in the "
"hierarchy. Thus, if an attribute is not found in :class:`DerivedClassName`, "
"it is searched for in :class:`Base1`, then (recursively) in the base classes "
"of :class:`Base1`, and if it was not found there, it was searched for in :"
"class:`Base2`, and so on."
"In fact, it is slightly more complex than that; the method resolution order "
"changes dynamically to support cooperative calls to :func:`super`.  This "
"approach is known in some other multiple-inheritance languages as call-next-"
"method and is more powerful than the super call found in single-inheritance "
"languages."
"Dynamic ordering is necessary because all cases of multiple inheritance "
"exhibit one or more diamond relationships (where at least one of the parent "
"classes can be accessed through multiple paths from the bottommost class).  "
"For example, all classes inherit from :class:`object`, so any case of "
"multiple inheritance provides more than one path to reach :class:`object`.  "
"To keep the base classes from being accessed more than once, the dynamic "
"algorithm linearizes the search order in a way that preserves the left-to-"
"right ordering specified in each class, that calls each parent only once, "
"and that is monotonic (meaning that a class can be subclassed without "
"affecting the precedence order of its parents). Taken together, these "
"properties make it possible to design reliable and extensible classes with "
"multiple inheritance.  For more detail, see https://www.python.org/download/"
"releases/2.3/mro/."
msgid "Private Variables"
"\"Private\" instance variables that cannot be accessed except from inside an "
"object don't exist in Python.  However, there is a convention that is "
"followed by most Python code: a name prefixed with an underscore (e.g. "
"``_spam``) should be treated as a non-public part of the API (whether it is "
"a function, a method or a data member).  It should be considered an "
"implementation detail and subject to change without notice."
"Since there is a valid use-case for class-private members (namely to avoid "
"name clashes of names with names defined by subclasses), there is limited "
"support for such a mechanism, called :dfn:`name mangling`.  Any identifier "
"of the form ``__spam`` (at least two leading underscores, at most one "
"trailing underscore) is textually replaced with ``_classname__spam``, where "
"``classname`` is the current class name with leading underscore(s) "
"stripped.  This mangling is done without regard to the syntactic position of "
"the identifier, as long as it occurs within the definition of a class."
"Name mangling is helpful for letting subclasses override methods without "
"breaking intraclass method calls.  For example::"
"The above example would work even if ``MappingSubclass`` were to introduce a "
"``__update`` identifier since it is replaced with ``_Mapping__update`` in "
"the ``Mapping`` class  and ``_MappingSubclass__update`` in the "
"``MappingSubclass`` class respectively."
"Note that the mangling rules are designed mostly to avoid accidents; it "
"still is possible to access or modify a variable that is considered "
"private.  This can even be useful in special circumstances, such as in the "
"debugger."
"Notice that code passed to ``exec()`` or ``eval()`` does not consider the "
"classname of the invoking class to be the current class; this is similar to "
"the effect of the ``global`` statement, the effect of which is likewise "
"restricted to code that is byte-compiled together.  The same restriction "
"applies to ``getattr()``, ``setattr()`` and ``delattr()``, as well as when "
"referencing ``__dict__`` directly."
msgid "Odds and Ends"
"Sometimes it is useful to have a data type similar to the Pascal \"record\" "
"or C \"struct\", bundling together a few named data items.  An empty class "
"definition will do nicely::"
"A piece of Python code that expects a particular abstract data type can "
"often be passed a class that emulates the methods of that data type "
"instead.  For instance, if you have a function that formats some data from a "
"file object, you can define a class with methods :meth:`read` and :meth:`!"
"readline` that get the data from a string buffer instead, and pass it as an "
"argument."
"Instance method objects have attributes, too: ``m.__self__`` is the instance "
"object with the method :meth:`m`, and ``m.__func__`` is the function object "
"corresponding to the method."
msgid "Iterators"
"By now you have probably noticed that most container objects can be looped "
"over using a :keyword:`for` statement::"
"This style of access is clear, concise, and convenient.  The use of "
"iterators pervades and unifies Python.  Behind the scenes, the :keyword:"
"`for` statement calls :func:`iter` on the container object.  The function "
"returns an iterator object that defines the method :meth:`~iterator."
"__next__` which accesses elements in the container one at a time.  When "
"there are no more elements, :meth:`~iterator.__next__` raises a :exc:"
"`StopIteration` exception which tells the :keyword:`!for` loop to "
"terminate.  You can call the :meth:`~iterator.__next__` method using the :"
"func:`next` built-in function; this example shows how it all works::"
"Having seen the mechanics behind the iterator protocol, it is easy to add "
"iterator behavior to your classes.  Define an :meth:`__iter__` method which "
"returns an object with a :meth:`~iterator.__next__` method.  If the class "
"defines :meth:`__next__`, then :meth:`__iter__` can just return ``self``::"
msgid "Generators"
":term:`Generators <generator>` are a simple and powerful tool for creating "
"iterators.  They are written like regular functions but use the :keyword:"
"`yield` statement whenever they want to return data.  Each time :func:`next` "
"is called on it, the generator resumes where it left off (it remembers all "
"the data values and which statement was last executed).  An example shows "
"that generators can be trivially easy to create::"
"Anything that can be done with generators can also be done with class-based "
"iterators as described in the previous section.  What makes generators so "
"compact is that the :meth:`__iter__` and :meth:`~generator.__next__` methods "
"are created automatically."
"Another key feature is that the local variables and execution state are "
"automatically saved between calls.  This made the function easier to write "
"and much more clear than an approach using instance variables like ``self."
"index`` and ``self.data``."
"In addition to automatic method creation and saving program state, when "
"generators terminate, they automatically raise :exc:`StopIteration`. In "
"combination, these features make it easy to create iterators with no more "
"effort than writing a regular function."
msgid "Generator Expressions"
"Some simple generators can be coded succinctly as expressions using a syntax "
"similar to list comprehensions but with parentheses instead of square "
"brackets. These expressions are designed for situations where the generator "
"is used right away by an enclosing function.  Generator expressions are more "
"compact but less versatile than full generator definitions and tend to be "
"more memory friendly than equivalent list comprehensions."
msgid "Examples::"
msgid "Footnotes"
msgstr "Przypisy"
"Except for one thing.  Module objects have a secret read-only attribute "
"called :attr:`~object.__dict__` which returns the dictionary used to "
"implement the module's namespace; the name :attr:`~object.__dict__` is an "
"attribute but not a global name. Obviously, using this violates the "
"abstraction of namespace implementation, and should be restricted to things "
"like post-mortem debuggers."
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