Add in enum34 1.1.6 (58c4cd7)
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https://bitbucket.org/stoneleaf/enum34/get/1.1.6.zip
Also added in misc files (Android.bp, METADATA, NOTICE, etc)
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Bug: 122778810
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Change-Id: I2dd62b9938f154fbe425da0475988ed1b99e6707
diff --git a/enum/doc/enum.rst b/enum/doc/enum.rst
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+``enum`` --- support for enumerations
+========================================
+
+.. :synopsis: enumerations are sets of symbolic names bound to unique, constant
+ values.
+.. :moduleauthor:: Ethan Furman <ethan@stoneleaf.us>
+.. :sectionauthor:: Barry Warsaw <barry@python.org>,
+.. :sectionauthor:: Eli Bendersky <eliben@gmail.com>,
+.. :sectionauthor:: Ethan Furman <ethan@stoneleaf.us>
+
+----------------
+
+An enumeration is a set of symbolic names (members) bound to unique, constant
+values. Within an enumeration, the members can be compared by identity, and
+the enumeration itself can be iterated over.
+
+
+Module Contents
+---------------
+
+This module defines two enumeration classes that can be used to define unique
+sets of names and values: ``Enum`` and ``IntEnum``. It also defines
+one decorator, ``unique``.
+
+``Enum``
+
+Base class for creating enumerated constants. See section `Functional API`_
+for an alternate construction syntax.
+
+``IntEnum``
+
+Base class for creating enumerated constants that are also subclasses of ``int``.
+
+``unique``
+
+Enum class decorator that ensures only one name is bound to any one value.
+
+
+Creating an Enum
+----------------
+
+Enumerations are created using the ``class`` syntax, which makes them
+easy to read and write. An alternative creation method is described in
+`Functional API`_. To define an enumeration, subclass ``Enum`` as
+follows::
+
+ >>> from enum import Enum
+ >>> class Color(Enum):
+ ... red = 1
+ ... green = 2
+ ... blue = 3
+
+Note: Nomenclature
+
+ - The class ``Color`` is an *enumeration* (or *enum*)
+ - The attributes ``Color.red``, ``Color.green``, etc., are
+ *enumeration members* (or *enum members*).
+ - The enum members have *names* and *values* (the name of
+ ``Color.red`` is ``red``, the value of ``Color.blue`` is
+ ``3``, etc.)
+
+Note:
+
+ Even though we use the ``class`` syntax to create Enums, Enums
+ are not normal Python classes. See `How are Enums different?`_ for
+ more details.
+
+Enumeration members have human readable string representations::
+
+ >>> print(Color.red)
+ Color.red
+
+...while their ``repr`` has more information::
+
+ >>> print(repr(Color.red))
+ <Color.red: 1>
+
+The *type* of an enumeration member is the enumeration it belongs to::
+
+ >>> type(Color.red)
+ <enum 'Color'>
+ >>> isinstance(Color.green, Color)
+ True
+ >>>
+
+Enum members also have a property that contains just their item name::
+
+ >>> print(Color.red.name)
+ red
+
+Enumerations support iteration. In Python 3.x definition order is used; in
+Python 2.x the definition order is not available, but class attribute
+``__order__`` is supported; otherwise, value order is used::
+
+ >>> class Shake(Enum):
+ ... __order__ = 'vanilla chocolate cookies mint' # only needed in 2.x
+ ... vanilla = 7
+ ... chocolate = 4
+ ... cookies = 9
+ ... mint = 3
+ ...
+ >>> for shake in Shake:
+ ... print(shake)
+ ...
+ Shake.vanilla
+ Shake.chocolate
+ Shake.cookies
+ Shake.mint
+
+The ``__order__`` attribute is always removed, and in 3.x it is also ignored
+(order is definition order); however, in the stdlib version it will be ignored
+but not removed.
+
+Enumeration members are hashable, so they can be used in dictionaries and sets::
+
+ >>> apples = {}
+ >>> apples[Color.red] = 'red delicious'
+ >>> apples[Color.green] = 'granny smith'
+ >>> apples == {Color.red: 'red delicious', Color.green: 'granny smith'}
+ True
+
+
+Programmatic access to enumeration members and their attributes
+---------------------------------------------------------------
+
+Sometimes it's useful to access members in enumerations programmatically (i.e.
+situations where ``Color.red`` won't do because the exact color is not known
+at program-writing time). ``Enum`` allows such access::
+
+ >>> Color(1)
+ <Color.red: 1>
+ >>> Color(3)
+ <Color.blue: 3>
+
+If you want to access enum members by *name*, use item access::
+
+ >>> Color['red']
+ <Color.red: 1>
+ >>> Color['green']
+ <Color.green: 2>
+
+If have an enum member and need its ``name`` or ``value``::
+
+ >>> member = Color.red
+ >>> member.name
+ 'red'
+ >>> member.value
+ 1
+
+
+Duplicating enum members and values
+-----------------------------------
+
+Having two enum members (or any other attribute) with the same name is invalid;
+in Python 3.x this would raise an error, but in Python 2.x the second member
+simply overwrites the first::
+
+ >>> # python 2.x
+ >>> class Shape(Enum):
+ ... square = 2
+ ... square = 3
+ ...
+ >>> Shape.square
+ <Shape.square: 3>
+
+ >>> # python 3.x
+ >>> class Shape(Enum):
+ ... square = 2
+ ... square = 3
+ Traceback (most recent call last):
+ ...
+ TypeError: Attempted to reuse key: 'square'
+
+However, two enum members are allowed to have the same value. Given two members
+A and B with the same value (and A defined first), B is an alias to A. By-value
+lookup of the value of A and B will return A. By-name lookup of B will also
+return A::
+
+ >>> class Shape(Enum):
+ ... __order__ = 'square diamond circle alias_for_square' # only needed in 2.x
+ ... square = 2
+ ... diamond = 1
+ ... circle = 3
+ ... alias_for_square = 2
+ ...
+ >>> Shape.square
+ <Shape.square: 2>
+ >>> Shape.alias_for_square
+ <Shape.square: 2>
+ >>> Shape(2)
+ <Shape.square: 2>
+
+
+Allowing aliases is not always desirable. ``unique`` can be used to ensure
+that none exist in a particular enumeration::
+
+ >>> from enum import unique
+ >>> @unique
+ ... class Mistake(Enum):
+ ... __order__ = 'one two three four' # only needed in 2.x
+ ... one = 1
+ ... two = 2
+ ... three = 3
+ ... four = 3
+ Traceback (most recent call last):
+ ...
+ ValueError: duplicate names found in <enum 'Mistake'>: four -> three
+
+Iterating over the members of an enum does not provide the aliases::
+
+ >>> list(Shape)
+ [<Shape.square: 2>, <Shape.diamond: 1>, <Shape.circle: 3>]
+
+The special attribute ``__members__`` is a dictionary mapping names to members.
+It includes all names defined in the enumeration, including the aliases::
+
+ >>> for name, member in sorted(Shape.__members__.items()):
+ ... name, member
+ ...
+ ('alias_for_square', <Shape.square: 2>)
+ ('circle', <Shape.circle: 3>)
+ ('diamond', <Shape.diamond: 1>)
+ ('square', <Shape.square: 2>)
+
+The ``__members__`` attribute can be used for detailed programmatic access to
+the enumeration members. For example, finding all the aliases::
+
+ >>> [name for name, member in Shape.__members__.items() if member.name != name]
+ ['alias_for_square']
+
+Comparisons
+-----------
+
+Enumeration members are compared by identity::
+
+ >>> Color.red is Color.red
+ True
+ >>> Color.red is Color.blue
+ False
+ >>> Color.red is not Color.blue
+ True
+
+Ordered comparisons between enumeration values are *not* supported. Enum
+members are not integers (but see `IntEnum`_ below)::
+
+ >>> Color.red < Color.blue
+ Traceback (most recent call last):
+ File "<stdin>", line 1, in <module>
+ TypeError: unorderable types: Color() < Color()
+
+.. warning::
+
+ In Python 2 *everything* is ordered, even though the ordering may not
+ make sense. If you want your enumerations to have a sensible ordering
+ check out the `OrderedEnum`_ recipe below.
+
+
+Equality comparisons are defined though::
+
+ >>> Color.blue == Color.red
+ False
+ >>> Color.blue != Color.red
+ True
+ >>> Color.blue == Color.blue
+ True
+
+Comparisons against non-enumeration values will always compare not equal
+(again, ``IntEnum`` was explicitly designed to behave differently, see
+below)::
+
+ >>> Color.blue == 2
+ False
+
+
+Allowed members and attributes of enumerations
+----------------------------------------------
+
+The examples above use integers for enumeration values. Using integers is
+short and handy (and provided by default by the `Functional API`_), but not
+strictly enforced. In the vast majority of use-cases, one doesn't care what
+the actual value of an enumeration is. But if the value *is* important,
+enumerations can have arbitrary values.
+
+Enumerations are Python classes, and can have methods and special methods as
+usual. If we have this enumeration::
+
+ >>> class Mood(Enum):
+ ... funky = 1
+ ... happy = 3
+ ...
+ ... def describe(self):
+ ... # self is the member here
+ ... return self.name, self.value
+ ...
+ ... def __str__(self):
+ ... return 'my custom str! {0}'.format(self.value)
+ ...
+ ... @classmethod
+ ... def favorite_mood(cls):
+ ... # cls here is the enumeration
+ ... return cls.happy
+
+Then::
+
+ >>> Mood.favorite_mood()
+ <Mood.happy: 3>
+ >>> Mood.happy.describe()
+ ('happy', 3)
+ >>> str(Mood.funky)
+ 'my custom str! 1'
+
+The rules for what is allowed are as follows: _sunder_ names (starting and
+ending with a single underscore) are reserved by enum and cannot be used;
+all other attributes defined within an enumeration will become members of this
+enumeration, with the exception of *__dunder__* names and descriptors (methods
+are also descriptors).
+
+Note:
+
+ If your enumeration defines ``__new__`` and/or ``__init__`` then
+ whatever value(s) were given to the enum member will be passed into
+ those methods. See `Planet`_ for an example.
+
+
+Restricted subclassing of enumerations
+--------------------------------------
+
+Subclassing an enumeration is allowed only if the enumeration does not define
+any members. So this is forbidden::
+
+ >>> class MoreColor(Color):
+ ... pink = 17
+ Traceback (most recent call last):
+ ...
+ TypeError: Cannot extend enumerations
+
+But this is allowed::
+
+ >>> class Foo(Enum):
+ ... def some_behavior(self):
+ ... pass
+ ...
+ >>> class Bar(Foo):
+ ... happy = 1
+ ... sad = 2
+ ...
+
+Allowing subclassing of enums that define members would lead to a violation of
+some important invariants of types and instances. On the other hand, it makes
+sense to allow sharing some common behavior between a group of enumerations.
+(See `OrderedEnum`_ for an example.)
+
+
+Pickling
+--------
+
+Enumerations can be pickled and unpickled::
+
+ >>> from enum.test_enum import Fruit
+ >>> from pickle import dumps, loads
+ >>> Fruit.tomato is loads(dumps(Fruit.tomato, 2))
+ True
+
+The usual restrictions for pickling apply: picklable enums must be defined in
+the top level of a module, since unpickling requires them to be importable
+from that module.
+
+Note:
+
+ With pickle protocol version 4 (introduced in Python 3.4) it is possible
+ to easily pickle enums nested in other classes.
+
+
+
+Functional API
+--------------
+
+The ``Enum`` class is callable, providing the following functional API::
+
+ >>> Animal = Enum('Animal', 'ant bee cat dog')
+ >>> Animal
+ <enum 'Animal'>
+ >>> Animal.ant
+ <Animal.ant: 1>
+ >>> Animal.ant.value
+ 1
+ >>> list(Animal)
+ [<Animal.ant: 1>, <Animal.bee: 2>, <Animal.cat: 3>, <Animal.dog: 4>]
+
+The semantics of this API resemble ``namedtuple``. The first argument
+of the call to ``Enum`` is the name of the enumeration.
+
+The second argument is the *source* of enumeration member names. It can be a
+whitespace-separated string of names, a sequence of names, a sequence of
+2-tuples with key/value pairs, or a mapping (e.g. dictionary) of names to
+values. The last two options enable assigning arbitrary values to
+enumerations; the others auto-assign increasing integers starting with 1. A
+new class derived from ``Enum`` is returned. In other words, the above
+assignment to ``Animal`` is equivalent to::
+
+ >>> class Animals(Enum):
+ ... ant = 1
+ ... bee = 2
+ ... cat = 3
+ ... dog = 4
+
+Pickling enums created with the functional API can be tricky as frame stack
+implementation details are used to try and figure out which module the
+enumeration is being created in (e.g. it will fail if you use a utility
+function in separate module, and also may not work on IronPython or Jython).
+The solution is to specify the module name explicitly as follows::
+
+ >>> Animals = Enum('Animals', 'ant bee cat dog', module=__name__)
+
+Derived Enumerations
+--------------------
+
+IntEnum
+^^^^^^^
+
+A variation of ``Enum`` is provided which is also a subclass of
+``int``. Members of an ``IntEnum`` can be compared to integers;
+by extension, integer enumerations of different types can also be compared
+to each other::
+
+ >>> from enum import IntEnum
+ >>> class Shape(IntEnum):
+ ... circle = 1
+ ... square = 2
+ ...
+ >>> class Request(IntEnum):
+ ... post = 1
+ ... get = 2
+ ...
+ >>> Shape == 1
+ False
+ >>> Shape.circle == 1
+ True
+ >>> Shape.circle == Request.post
+ True
+
+However, they still can't be compared to standard ``Enum`` enumerations::
+
+ >>> class Shape(IntEnum):
+ ... circle = 1
+ ... square = 2
+ ...
+ >>> class Color(Enum):
+ ... red = 1
+ ... green = 2
+ ...
+ >>> Shape.circle == Color.red
+ False
+
+``IntEnum`` values behave like integers in other ways you'd expect::
+
+ >>> int(Shape.circle)
+ 1
+ >>> ['a', 'b', 'c'][Shape.circle]
+ 'b'
+ >>> [i for i in range(Shape.square)]
+ [0, 1]
+
+For the vast majority of code, ``Enum`` is strongly recommended,
+since ``IntEnum`` breaks some semantic promises of an enumeration (by
+being comparable to integers, and thus by transitivity to other
+unrelated enumerations). It should be used only in special cases where
+there's no other choice; for example, when integer constants are
+replaced with enumerations and backwards compatibility is required with code
+that still expects integers.
+
+
+Others
+^^^^^^
+
+While ``IntEnum`` is part of the ``enum`` module, it would be very
+simple to implement independently::
+
+ class IntEnum(int, Enum):
+ pass
+
+This demonstrates how similar derived enumerations can be defined; for example
+a ``StrEnum`` that mixes in ``str`` instead of ``int``.
+
+Some rules:
+
+1. When subclassing ``Enum``, mix-in types must appear before
+ ``Enum`` itself in the sequence of bases, as in the ``IntEnum``
+ example above.
+2. While ``Enum`` can have members of any type, once you mix in an
+ additional type, all the members must have values of that type, e.g.
+ ``int`` above. This restriction does not apply to mix-ins which only
+ add methods and don't specify another data type such as ``int`` or
+ ``str``.
+3. When another data type is mixed in, the ``value`` attribute is *not the
+ same* as the enum member itself, although it is equivalant and will compare
+ equal.
+4. %-style formatting: ``%s`` and ``%r`` call ``Enum``'s ``__str__`` and
+ ``__repr__`` respectively; other codes (such as ``%i`` or ``%h`` for
+ IntEnum) treat the enum member as its mixed-in type.
+
+ Note: Prior to Python 3.4 there is a bug in ``str``'s %-formatting: ``int``
+ subclasses are printed as strings and not numbers when the ``%d``, ``%i``,
+ or ``%u`` codes are used.
+5. ``str.__format__`` (or ``format``) will use the mixed-in
+ type's ``__format__``. If the ``Enum``'s ``str`` or
+ ``repr`` is desired use the ``!s`` or ``!r`` ``str`` format codes.
+
+
+Decorators
+----------
+
+unique
+^^^^^^
+
+A ``class`` decorator specifically for enumerations. It searches an
+enumeration's ``__members__`` gathering any aliases it finds; if any are
+found ``ValueError`` is raised with the details::
+
+ >>> @unique
+ ... class NoDupes(Enum):
+ ... first = 'one'
+ ... second = 'two'
+ ... third = 'two'
+ Traceback (most recent call last):
+ ...
+ ValueError: duplicate names found in <enum 'NoDupes'>: third -> second
+
+
+Interesting examples
+--------------------
+
+While ``Enum`` and ``IntEnum`` are expected to cover the majority of
+use-cases, they cannot cover them all. Here are recipes for some different
+types of enumerations that can be used directly, or as examples for creating
+one's own.
+
+
+AutoNumber
+^^^^^^^^^^
+
+Avoids having to specify the value for each enumeration member::
+
+ >>> class AutoNumber(Enum):
+ ... def __new__(cls):
+ ... value = len(cls.__members__) + 1
+ ... obj = object.__new__(cls)
+ ... obj._value_ = value
+ ... return obj
+ ...
+ >>> class Color(AutoNumber):
+ ... __order__ = "red green blue" # only needed in 2.x
+ ... red = ()
+ ... green = ()
+ ... blue = ()
+ ...
+ >>> Color.green.value == 2
+ True
+
+Note:
+
+ The `__new__` method, if defined, is used during creation of the Enum
+ members; it is then replaced by Enum's `__new__` which is used after
+ class creation for lookup of existing members. Due to the way Enums are
+ supposed to behave, there is no way to customize Enum's `__new__`.
+
+
+UniqueEnum
+^^^^^^^^^^
+
+Raises an error if a duplicate member name is found instead of creating an
+alias::
+
+ >>> class UniqueEnum(Enum):
+ ... def __init__(self, *args):
+ ... cls = self.__class__
+ ... if any(self.value == e.value for e in cls):
+ ... a = self.name
+ ... e = cls(self.value).name
+ ... raise ValueError(
+ ... "aliases not allowed in UniqueEnum: %r --> %r"
+ ... % (a, e))
+ ...
+ >>> class Color(UniqueEnum):
+ ... red = 1
+ ... green = 2
+ ... blue = 3
+ ... grene = 2
+ Traceback (most recent call last):
+ ...
+ ValueError: aliases not allowed in UniqueEnum: 'grene' --> 'green'
+
+
+OrderedEnum
+^^^^^^^^^^^
+
+An ordered enumeration that is not based on ``IntEnum`` and so maintains
+the normal ``Enum`` invariants (such as not being comparable to other
+enumerations)::
+
+ >>> class OrderedEnum(Enum):
+ ... def __ge__(self, other):
+ ... if self.__class__ is other.__class__:
+ ... return self._value_ >= other._value_
+ ... return NotImplemented
+ ... def __gt__(self, other):
+ ... if self.__class__ is other.__class__:
+ ... return self._value_ > other._value_
+ ... return NotImplemented
+ ... def __le__(self, other):
+ ... if self.__class__ is other.__class__:
+ ... return self._value_ <= other._value_
+ ... return NotImplemented
+ ... def __lt__(self, other):
+ ... if self.__class__ is other.__class__:
+ ... return self._value_ < other._value_
+ ... return NotImplemented
+ ...
+ >>> class Grade(OrderedEnum):
+ ... __ordered__ = 'A B C D F'
+ ... A = 5
+ ... B = 4
+ ... C = 3
+ ... D = 2
+ ... F = 1
+ ...
+ >>> Grade.C < Grade.A
+ True
+
+
+Planet
+^^^^^^
+
+If ``__new__`` or ``__init__`` is defined the value of the enum member
+will be passed to those methods::
+
+ >>> class Planet(Enum):
+ ... MERCURY = (3.303e+23, 2.4397e6)
+ ... VENUS = (4.869e+24, 6.0518e6)
+ ... EARTH = (5.976e+24, 6.37814e6)
+ ... MARS = (6.421e+23, 3.3972e6)
+ ... JUPITER = (1.9e+27, 7.1492e7)
+ ... SATURN = (5.688e+26, 6.0268e7)
+ ... URANUS = (8.686e+25, 2.5559e7)
+ ... NEPTUNE = (1.024e+26, 2.4746e7)
+ ... def __init__(self, mass, radius):
+ ... self.mass = mass # in kilograms
+ ... self.radius = radius # in meters
+ ... @property
+ ... def surface_gravity(self):
+ ... # universal gravitational constant (m3 kg-1 s-2)
+ ... G = 6.67300E-11
+ ... return G * self.mass / (self.radius * self.radius)
+ ...
+ >>> Planet.EARTH.value
+ (5.976e+24, 6378140.0)
+ >>> Planet.EARTH.surface_gravity
+ 9.802652743337129
+
+
+How are Enums different?
+------------------------
+
+Enums have a custom metaclass that affects many aspects of both derived Enum
+classes and their instances (members).
+
+
+Enum Classes
+^^^^^^^^^^^^
+
+The ``EnumMeta`` metaclass is responsible for providing the
+``__contains__``, ``__dir__``, ``__iter__`` and other methods that
+allow one to do things with an ``Enum`` class that fail on a typical
+class, such as ``list(Color)`` or ``some_var in Color``. ``EnumMeta`` is
+responsible for ensuring that various other methods on the final ``Enum``
+class are correct (such as ``__new__``, ``__getnewargs__``,
+``__str__`` and ``__repr__``).
+
+.. note::
+
+ ``__dir__`` is not changed in the Python 2 line as it messes up some
+ of the decorators included in the stdlib.
+
+
+Enum Members (aka instances)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The most interesting thing about Enum members is that they are singletons.
+``EnumMeta`` creates them all while it is creating the ``Enum``
+class itself, and then puts a custom ``__new__`` in place to ensure
+that no new ones are ever instantiated by returning only the existing
+member instances.
+
+
+Finer Points
+^^^^^^^^^^^^
+
+``Enum`` members are instances of an ``Enum`` class, and even though they
+are accessible as `EnumClass.member1.member2`, they should not be
+accessed directly from the member as that lookup may fail or, worse,
+return something besides the ``Enum`` member you were looking for
+(changed in version 1.1.1)::
+
+ >>> class FieldTypes(Enum):
+ ... name = 1
+ ... value = 2
+ ... size = 3
+ ...
+ >>> FieldTypes.value.size
+ <FieldTypes.size: 3>
+ >>> FieldTypes.size.value
+ 3
+
+The ``__members__`` attribute is only available on the class.
+
+In Python 3.x ``__members__`` is always an ``OrderedDict``, with the order being
+the definition order. In Python 2.7 ``__members__`` is an ``OrderedDict`` if
+``__order__`` was specified, and a plain ``dict`` otherwise. In all other Python
+2.x versions ``__members__`` is a plain ``dict`` even if ``__order__`` was specified
+as the ``OrderedDict`` type didn't exist yet.
+
+If you give your ``Enum`` subclass extra methods, like the `Planet`_
+class above, those methods will show up in a `dir` of the member,
+but not of the class::
+
+ >>> dir(Planet)
+ ['EARTH', 'JUPITER', 'MARS', 'MERCURY', 'NEPTUNE', 'SATURN', 'URANUS',
+ 'VENUS', '__class__', '__doc__', '__members__', '__module__']
+ >>> dir(Planet.EARTH)
+ ['__class__', '__doc__', '__module__', 'name', 'surface_gravity', 'value']
+
+A ``__new__`` method will only be used for the creation of the
+``Enum`` members -- after that it is replaced. This means if you wish to
+change how ``Enum`` members are looked up you either have to write a
+helper function or a ``classmethod``.