# coding=utf-8 """ past: compatibility with Python 2 from Python 3 =============================================== ``past`` is a package to aid with Python 2/3 compatibility. Whereas ``future`` contains backports of Python 3 constructs to Python 2, ``past`` provides implementations of some Python 2 constructs in Python 3 and tools to import and run Python 2 code in Python 3. It is intended to be used sparingly, as a way of running old Python 2 code from Python 3 until the code is ported properly. Potential uses for libraries: - as a step in porting a Python 2 codebase to Python 3 (e.g. with the ``futurize`` script) - to provide Python 3 support for previously Python 2-only libraries with the same APIs as on Python 2 -- particularly with regard to 8-bit strings (the ``past.builtins.str`` type). - to aid in providing minimal-effort Python 3 support for applications using libraries that do not yet wish to upgrade their code properly to Python 3, or wish to upgrade it gradually to Python 3 style. Here are some code examples that run identically on Python 3 and 2:: >>> from past.builtins import str as oldstr >>> philosopher = oldstr(u'\u5b54\u5b50'.encode('utf-8')) >>> # This now behaves like a Py2 byte-string on both Py2 and Py3. >>> # For example, indexing returns a Python 2-like string object, not >>> # an integer: >>> philosopher[0] '\xe5' >>> type(philosopher[0]) <past.builtins.oldstr> >>> # List-producing versions of range, reduce, map, filter >>> from past.builtins import range, reduce >>> range(10) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] >>> reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) 15 >>> # Other functions removed in Python 3 are resurrected ... >>> from past.builtins import execfile >>> execfile('myfile.py') >>> from past.builtins import raw_input >>> name = raw_input('What is your name? ') What is your name? [cursor] >>> from past.builtins import reload >>> reload(mymodule) # equivalent to imp.reload(mymodule) in Python 3 >>> from past.builtins import xrange >>> for i in xrange(10): ... pass It also provides import hooks so you can import and use Python 2 modules like this:: $ python3 >>> from past.translation import autotranslate >>> authotranslate('mypy2module') >>> import mypy2module until the authors of the Python 2 modules have upgraded their code. Then, for example:: >>> mypy2module.func_taking_py2_string(oldstr(b'abcd')) Credits ------- :Author: Ed Schofield, Jordan M. Adler, et al :Sponsor: Python Charmers Pty Ltd, Australia: http://pythoncharmers.com Licensing --------- Copyright 2013-2019 Python Charmers Pty Ltd, Australia. The software is distributed under an MIT licence. See LICENSE.txt. """ from future import __version__, __copyright__, __license__ __title__ = 'past' __author__ = 'Ed Schofield'