aenum 1.3.2

Advanced Enumerations (compatible with Python's stdlib Enum), NamedTuples, and NamedConstants

aenum --- support for advanced enumerations, namedtuples, and constants
===========================================================================

aenum includes the new Python stdlib enum module available in Python 3.4
backported for previous versions of Python from 2.7 and 3.3+
tested on 2.7, and 3.3+


An ``Enum`` 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.

A ``NamedTuple`` is a class-based, fixed-length tuple with a name for each
possible position accessible using attribute-access notation.

A ``NamedConstant`` is a class whose members cannot be rebound; it lacks all other
``Enum`` capabilities, however; consequently, it can have duplicate values.
There is also a ``module`` function that can insert the ``NamedConstant`` class
into ``sys.modules`` where it will appear to be a module whose top-level
names cannot be rebound.


Module Contents
---------------

``NamedTuple``
^^^^^^^^^^^^^^
Base class for ``creating NamedTuples``_, either by subclassing or via it's
functional API.

``NamedConstant``
^^^^^^^^^^^^^^^^^
NamedConstant class for creating groups of constants. These names cannot be rebound
to other values.

``Enum``
^^^^^^^^
Base class for creating enumerated constants. See section ``Enum Functional API``_
for an alternate construction syntax.

``IntEnum``
^^^^^^^^^^^
Base class for creating enumerated constants that are also subclasses of ``int``.

``AutoNumberEnum``
^^^^^^^^^^^^^^^^^^
Derived class that automatically assigns an ``int`` value to each member.

``OrderedEnum``
^^^^^^^^^^^^^^^
Derived class that adds ``<``, ``<=``, ``>=``, and ``>`` methods to an ``Enum``.

``UniqueEnum``
^^^^^^^^^^^^^^
Derived class that ensures only one name is bound to any one value.

``unique``
^^^^^^^^^^
Enum class decorator that ensures only one name is bound to any one value.

``constant``
^^^^^^^^^^^^
Descriptor to add constant values to an ``Enum``

``convert``
^^^^^^^^^^^
Helper to transform target global variables into an ``Enum``.

``enum``
^^^^^^^^
Helper for specifying keyword arguments when creating ``Enum`` members.

``export``
^^^^^^^^^^`
Helper for inserting ``Enum`` members into a namespace (usually ``globals()``.

``extend_enum``
^^^^^^^^^^^^^^^
Helper for adding new ``Enum`` members after creation.

``module``
^^^^^^^^^^
Function to take a ``NamedConstant`` or ``Enum`` class and insert it into
``sys.modules`` with the affect of a module whose top-level constant and
member names cannot be rebound.

``skip``
^^^^^^^^
Descriptor to add a normal (non-``Enum`` member) attribute to an ``Enum``
or ``NamedConstant``.


Creating an Enum
----------------

Enumerations can be created using the ``class`` syntax, which makes them
easy to read and write. To define an enumeration, subclass ``Enum`` as
follows::

>>> from aenum import Enum
>>> class Color(Enum):
... red = 1
... green = 2
... blue = 3

The ``Enum`` class is also 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>]


Creating NamedTuples
--------------------

Simple
^^^^^^

The most common way to create a new NamedTuple will be via the functional API::

>>> from aenum import NamedTuple
>>> Book = NamedTuple('Book', 'title author genre', module=__name__)

Advanced
^^^^^^^^

The simple method of creating ``NamedTuples`` requires always specifying all
possible arguments when creating instances; failure to do so will raise
exceptions.

However, it is possible to specify both docstrings and default values when
creating a ``NamedTuple`` using the class method::

>>> class Point(NamedTuple):
... x = 0, 'horizontal coordinate', 0
... y = 1, 'vertical coordinate', 0
...
>>> Point()
Point(x=0, y=0)


Creating NamedConstants
------------------

>>> class K(NamedConstant):
... PI = 3.141596
... TAU = 2 * PI
...
>>> K.TAU
6.283192