File indexing completed on 2024-04-28 15:53:57

 #!/usr/bin/env python2.7
 # -*- coding: utf-8 -*-
 """:synopsis: Future statement definitions
 
 
 :mod:`__future__` is a real module, and serves three purposes:
 
 * To avoid confusing existing tools that analyze import statements and expect to
 find the modules they're importing.
 
 * To ensure that :ref:`future statements <future>` run under releases prior to
 2.1 at least yield runtime exceptions (the import of :mod:`__future__` will
 fail, because there was no module of that name prior to 2.1).
 
 * To document when incompatible changes were introduced, and when they will be
 --- or were --- made mandatory.  This is a form of executable documentation, and
 can be inspected programmatically via importing :mod:`__future__` and examining
 its contents.
 
 Each statement in :file:`__future__.py` is of the form::
 
 FeatureName = _Feature(OptionalRelease, MandatoryRelease,
 CompilerFlag)
 
 
 where, normally, *OptionalRelease* is less than *MandatoryRelease*, and both are
 5-tuples of the same form as ``sys.version_info``::
 
 (PY_MAJOR_VERSION, # the 2 in 2.1.0a3; an int
 PY_MINOR_VERSION, # the 1; an int
 PY_MICRO_VERSION, # the 0; an int
 PY_RELEASE_LEVEL, # "alpha", "beta", "candidate" or "final"; string
 PY_RELEASE_SERIAL # the 3; an int
 )
 
 *OptionalRelease* records the first release in which the feature was accepted.
 
 In the case of a *MandatoryRelease* that has not yet occurred,
 *MandatoryRelease* predicts the release in which the feature will become part of
 the language.
 
 Else *MandatoryRelease* records when the feature became part of the language; in
 releases at or after that, modules no longer need a future statement to use the
 feature in question, but may continue to use such imports.
 
 *MandatoryRelease* may also be ``None``, meaning that a planned feature got
 dropped.
 
 Instances of class :class:`_Feature` have two corresponding methods,
 :meth:`getOptionalRelease` and :meth:`getMandatoryRelease`.
 
 *CompilerFlag* is the (bitfield) flag that should be passed in the fourth
 argument to the built-in function :func:`compile` to enable the feature in
 dynamically compiled code.  This flag is stored in the :attr:`compiler_flag`
 attribute on :class:`_Feature` instances.
 
 No feature description will ever be deleted from :mod:`__future__`. Since its
 introduction in Python 2.1 the following features have found their way into the
 language using this mechanism:
 
 +------------------+-------------+--------------+---------------------------------------------+
 | feature          | optional in | mandatory in | effect                                      |
 +==================+=============+==============+=============================================+
 | nested_scopes    | 2.1.0b1     | 2.2          | :pep:`227`:                                 |
 |                  |             |              | *Statically Nested Scopes*                  |
 +------------------+-------------+--------------+---------------------------------------------+
 | generators       | 2.2.0a1     | 2.3          | :pep:`255`:                                 |
 |                  |             |              | *Simple Generators*                         |
 +------------------+-------------+--------------+---------------------------------------------+
 | division         | 2.2.0a2     | 3.0          | :pep:`238`:                                 |
 |                  |             |              | *Changing the Division Operator*            |
 +------------------+-------------+--------------+---------------------------------------------+
 | absolute_import  | 2.5.0a1     | 2.7          | :pep:`328`:                                 |
 |                  |             |              | *Imports: Multi-Line and Absolute/Relative* |
 +------------------+-------------+--------------+---------------------------------------------+
 | with_statement   | 2.5.0a1     | 2.6          | :pep:`343`:                                 |
 |                  |             |              | *The "with" Statement*                      |
 +------------------+-------------+--------------+---------------------------------------------+
 | print_function   | 2.6.0a2     | 3.0          | :pep:`3105`:                                |
 |                  |             |              | *Make print a function*                     |
 +------------------+-------------+--------------+---------------------------------------------+
 | unicode_literals | 2.6.0a2     | 3.0          | :pep:`3112`:                                |
 |                  |             |              | *Bytes literals in Python 3000*             |
 +------------------+-------------+--------------+---------------------------------------------+
 
 """
 
 def nested_scopes(): pass
 def generators(): pass
 def print_function(): pass
 def division(): pass
 def absolute_import(): pass
 def with_statement(): pass
 def unicode_literals(): pass