[Python-checkins] r88332 - python/branches/py3k/Doc/howto/pyporting.rst
brett.cannon
python-checkins at python.org
Thu Feb 3 23:14:58 CET 2011
Author: brett.cannon
Date: Thu Feb 3 23:14:58 2011
New Revision: 88332
Log:
use 3-space indents.
Modified:
python/branches/py3k/Doc/howto/pyporting.rst
Modified: python/branches/py3k/Doc/howto/pyporting.rst
==============================================================================
--- python/branches/py3k/Doc/howto/pyporting.rst (original)
+++ python/branches/py3k/Doc/howto/pyporting.rst Thu Feb 3 23:14:58 2011
@@ -8,14 +8,14 @@
.. topic:: Abstract
- With Python 3 being the future of Python while Python 2 is still in active
- use, it is good to have your project available for both major releases of
- Python. This guide is meant to help you choose which strategy works best
- for your project to support both Python 2 & 3 along with how to execute
- that strategy.
+ With Python 3 being the future of Python while Python 2 is still in active
+ use, it is good to have your project available for both major releases of
+ Python. This guide is meant to help you choose which strategy works best
+ for your project to support both Python 2 & 3 along with how to execute
+ that strategy.
- If you are looking to port an extension module instead of pure Python code,
- please see http://docs.python.org/py3k/howto/cporting.html .
+ If you are looking to port an extension module instead of pure Python code,
+ please see http://docs.python.org/py3k/howto/cporting.html .
Choosing a Strategy
@@ -70,20 +70,20 @@
(from
http://techspot.zzzeek.org/2011/01/24/zzzeek-s-guide-to-python-3-porting/)::
- setup(
- name='Your Library',
- version='1.0',
- classifiers=[
- # make sure to use :: Python *and* :: Python :: 3 so
- # that pypi can list the package on the python 3 page
- 'Programming Language :: Python',
- 'Programming Language :: Python :: 3'
- ],
- packages=['yourlibrary'],
- # make sure to add custom_fixers to the MANIFEST.in
- include_package_data=True,
- # ...
- )
+ setup(
+ name='Your Library',
+ version='1.0',
+ classifiers=[
+ # make sure to use :: Python *and* :: Python :: 3 so
+ # that pypi can list the package on the python 3 page
+ 'Programming Language :: Python',
+ 'Programming Language :: Python :: 3'
+ ],
+ packages=['yourlibrary'],
+ # make sure to add custom_fixers to the MANIFEST.in
+ include_package_data=True,
+ # ...
+ )
Doing so will cause your project to show up in the
@@ -340,25 +340,25 @@
``__str__()`` for you (code from
http://lucumr.pocoo.org/2011/1/22/forwards-compatible-python/)::
- import sys
+ import sys
- class UnicodeMixin(object):
+ class UnicodeMixin(object):
- """Mixin class to handle defining the proper __str__/__unicode__
- methods in Python 2 or 3."""
+ """Mixin class to handle defining the proper __str__/__unicode__
+ methods in Python 2 or 3."""
- if sys.version_info[0] >= 3: # Python 3
- def __str__(self):
- return self.__unicode__()
- else: # Python 2
- def __str__(self):
- return self.__unicode__().encode('utf8')
+ if sys.version_info[0] >= 3: # Python 3
+ def __str__(self):
+ return self.__unicode__()
+ else: # Python 2
+ def __str__(self):
+ return self.__unicode__().encode('utf8')
- class Spam(UnicodeMixin):
+ class Spam(UnicodeMixin):
- def __unicode__(self):
- return u'spam-spam-bacon-spam' # 2to3 will remove the 'u' prefix
+ def __unicode__(self):
+ return u'spam-spam-bacon-spam' # 2to3 will remove the 'u' prefix
Specify when opening a file as binary
@@ -380,11 +380,11 @@
'''''''''''''''''''''''''
In Python 2, the following worked::
- >>> exc = Exception(1, 2, 3)
- >>> exc.args[1]
- 2
- >>> exc[1] # Python 2 only!
- 2
+ >>> exc = Exception(1, 2, 3)
+ >>> exc.args[1]
+ 2
+ >>> exc[1] # Python 2 only!
+ 2
But in Python 3, indexing directly off of an exception is an error. You need to
make sure to only index on :attr:`BaseException.args` attribute which is a
@@ -426,13 +426,13 @@
To manually convert source code using 2to3_, you use the ``2to3`` script that
is installed with Python 2.6 and later.::
- 2to3 <directory or file to convert>
+ 2to3 <directory or file to convert>
This will cause 2to3 to write out a diff with all of the fixers applied for the
converted source code. If you would like 2to3 to go ahead and apply the changes
you can pass it the ``-w`` flag::
- 2to3 -w <stuff to convert>
+ 2to3 -w <stuff to convert>
There are other flags available to control exactly which fixers are applied,
etc.
@@ -444,20 +444,20 @@
:mod:`distutils` or Distribute_ run 2to3_ on your behalf.
For distutils, use the following idiom::
- try: # Python 3
- from distutils.command.build_py import build_py_2to3 as build_py
- except ImportError: # Python 2
- from distutils.command.build_py import build_py
-
- setup(cmdclass = {'build_py':build_py},
- # ...
- )
-
-For Distribute::
-
- setup(use_2to3=True,
- # ...
- )
+ try: # Python 3
+ from distutils.command.build_py import build_py_2to3 as build_py
+ except ImportError: # Python 2
+ from distutils.command.build_py import build_py
+
+ setup(cmdclass = {'build_py':build_py},
+ # ...
+ )
+
+ For Distribute::
+
+ setup(use_2to3=True,
+ # ...
+ )
This will allow you to not have to distribute a separate Python 3 version of
your project. It does require, though, that when you perform development that
@@ -526,30 +526,30 @@
accessing the currently raised exception. In Python 2 the syntax to access the
current exception is::
- try:
- raise Exception()
- except Exception, exc:
- # Current exception is 'exc'
- pass
+ try:
+ raise Exception()
+ except Exception, exc:
+ # Current exception is 'exc'
+ pass
This syntax changed in Python 3 to::
- try:
- raise Exception()
- except Exception as exc:
- # Current exception is 'exc'
- pass
+ try:
+ raise Exception()
+ except Exception as exc:
+ # Current exception is 'exc'
+ pass
Because of this syntax change you must change to capturing the current
exception to::
- try:
- raise Exception()
- except Exception:
- import sys
- exc = sys.exc_info()[1]
- # Current exception is 'exc'
- pass
+ try:
+ raise Exception()
+ except Exception:
+ import sys
+ exc = sys.exc_info()[1]
+ # Current exception is 'exc'
+ pass
You can get more information about the raised exception from
:func:`sys.exc_info` than simply the current exception instance, but you most
More information about the Python-checkins
mailing list