| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455 |
- limitations of the ``future`` module and differences between Py2 and Py3 that are not (yet) handled
- ===================================================================================================
- The following attributes on functions in Python 3 are not provided in Python
- 2.7:
- __func__: see six.get_method_function()
- __self__: see six.get_method_self()
- __self__.__class__
- Limitations of the ``futurize`` script
- --------------------------------------
- The ``futurize`` script is not yet mature; like ``2to3``, on which it is based,
- it makes mistakes. Nevertheless, it should be useful for automatically
- performing a lot of the repetitive code-substitution tasks when porting from
- Py2 to Py2/3.
- Some new Python 3.3 features that cause SyntaxErrors on earlier versions
- are not currently handled by the ``futurize`` script. This includes:
- - ``yield ... from`` syntax for generators in Py3.3
- - ``raise ... from`` syntax for exceptions. (This is simple to fix
- manually by creating a temporary variable.)
- Also:
- - Usage of ``file('myfile', 'w')`` as a synonym for ``open`` doesn't seem
- to be converted currently.
- - ``isinstance(var, basestring)`` should sometimes be converted to
- ``isinstance(var, str) or isinstance(var, bytes)``, or sometimes simply
- ``isinstance(var, str)``, depending on the context. Currently it is always
- converted to ``isinstance(var, str)``.
- - Caveats with bytes indexing!::
- b'\x00'[0] != 0
- b'\x01'[0] != 1
-
- ``futurize`` does not yet wrap all byte-string literals in a ``bytes()``
- call. This is on the to-do list. See :ref:`bytes-object` for more information.
- Notes
- -----
- - Ensure you are using new-style classes on Py2. Py3 doesn't require
- inheritance from ``object`` for this, but Py2 does. ``pasteurize``
- adds this back in automatically, but ensure you do this too
- when writing your classes, otherwise weird breakage when e.g. calling
- ``super()`` may occur.
|