[Tutor] regex to promote Py 2 to Py 3?

[eryksun]

On Tue, Apr 16, 2013 at 9:02 PM, Jim Mooney <cybervigilante at gmail.com> wrote:
> So for online progs, examples, ebooks, etc, that still have Py 2
> examples I can copy, has anyone come up with a nice regex package to
> do most of the conversions and produce a mostly Py3 from a Py2? That
> might make some things a bit easier.

Generally the 2to3 script does an OK job. If you're using Windows it's
[Python_Dir]\Tools\Scripts\2to3.py.

http://docs.python.org/3/library/2to3

lib2to3 doesn't have a stable API, but you can use it in the REPL if
you want to experiment:

    >>> from lib2to3.refactor import RefactoringTool
    >>> rt = RefactoringTool(['lib2to3.fixes.fix_print'])

    >>> code2 = r'''
    ... for s in strings:
    ...     print >>myfile, s,
    ... '''

    >>> code3 = str(rt.refactor_string(code2, '<string>'))
    >>> print(code3)

    for s in strings:
        print(s, end=' ', file=myfile)

If you want all the fixes applied, you can use

    >>> from lib2to3.refactor import (
    ...   RefactoringTool, get_fixers_from_package)

    >>> rt = RefactoringTool(get_fixers_from_package('lib2to3.fixes'))

    >>> code2 = r'''
    ... class Test(object):
    ...     __metaclass__ = MetaTest
    ... '''
    >>> code3 = str(r.refactor_string(code2, '<string>'))
    >>> print(code3)

    class Test(object, metaclass=MetaTest):
        pass