diff options
author | Benjamin Peterson <benjamin@python.org> | 2008-09-08 23:05:23 (GMT) |
---|---|---|
committer | Benjamin Peterson <benjamin@python.org> | 2008-09-08 23:05:23 (GMT) |
commit | ae5360b31eb9bc78de48dd263f07ff247f86213a (patch) | |
tree | bf19f4fbfd79953ae4f5d6c62f6493dc0b848874 /Doc/library/2to3.rst | |
parent | e5b4ca6c998ca64681a8f1259c244da02313fad4 (diff) | |
download | cpython-ae5360b31eb9bc78de48dd263f07ff247f86213a.zip cpython-ae5360b31eb9bc78de48dd263f07ff247f86213a.tar.gz cpython-ae5360b31eb9bc78de48dd263f07ff247f86213a.tar.bz2 |
Merged revisions 66141,66145,66150,66180,66211,66217,66219,66226,66231,66244,66246,66249-66250,66264,66268,66272,66294,66306 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
........
r66141 | gregory.p.smith | 2008-09-02 00:29:51 -0500 (Tue, 02 Sep 2008) | 3 lines
Issue #3678: Correctly pass LDFLAGS and LDLAST to the linker on shared
library targets in the Makefile.
........
r66145 | marc-andre.lemburg | 2008-09-02 05:32:34 -0500 (Tue, 02 Sep 2008) | 5 lines
Add quotes around the file name to avoid issues with spaces.
Closes #3719.
........
r66150 | marc-andre.lemburg | 2008-09-02 07:11:19 -0500 (Tue, 02 Sep 2008) | 3 lines
Add news item for #3719.
........
r66180 | vinay.sajip | 2008-09-03 04:20:05 -0500 (Wed, 03 Sep 2008) | 1 line
Issue #3726: Allowed spaces in separators in logging configuration files.
........
r66211 | vinay.sajip | 2008-09-04 02:31:21 -0500 (Thu, 04 Sep 2008) | 1 line
Issue #3772: Fixed regression problem in StreamHandler.emit().
........
r66217 | andrew.kuchling | 2008-09-04 08:26:24 -0500 (Thu, 04 Sep 2008) | 1 line
#3671: various corrections and markup fixes noted by Kent Johnson
........
r66219 | hirokazu.yamamoto | 2008-09-04 09:25:30 -0500 (Thu, 04 Sep 2008) | 1 line
Added NEWS
........
r66226 | benjamin.peterson | 2008-09-04 18:31:27 -0500 (Thu, 04 Sep 2008) | 1 line
flesh out the documentation on using 2to3
........
r66231 | andrew.kuchling | 2008-09-05 10:15:56 -0500 (Fri, 05 Sep 2008) | 1 line
#3671: Typo fix
........
r66244 | jesse.noller | 2008-09-05 20:20:11 -0500 (Fri, 05 Sep 2008) | 2 lines
Fix typo in multiprocessing doc, cancel_join_thread was missing _thread
........
r66246 | benjamin.peterson | 2008-09-05 22:00:00 -0500 (Fri, 05 Sep 2008) | 1 line
actually tell the name of the flag to use
........
r66249 | andrew.kuchling | 2008-09-06 07:50:05 -0500 (Sat, 06 Sep 2008) | 1 line
Various corrections
........
r66250 | andrew.kuchling | 2008-09-06 08:04:02 -0500 (Sat, 06 Sep 2008) | 1 line
#3040: include 'dest' argument in example; trim some trailing whitespace
........
r66264 | benjamin.peterson | 2008-09-06 14:42:39 -0500 (Sat, 06 Sep 2008) | 1 line
docs are pretty good about new-style classes these days
........
r66268 | andrew.kuchling | 2008-09-06 15:28:01 -0500 (Sat, 06 Sep 2008) | 1 line
#3669 from Robert Lehmann: simplify use of iterator in example
........
r66272 | andrew.kuchling | 2008-09-06 16:26:02 -0500 (Sat, 06 Sep 2008) | 1 line
#1317: describe the does_esmtp, ehlo_resp, esmtp_features, and helo_resp attributes
........
r66294 | georg.brandl | 2008-09-07 12:00:17 -0500 (Sun, 07 Sep 2008) | 2 lines
Add a new howto about Python and the web, by Marek Kubica.
........
r66306 | mark.summerfield | 2008-09-08 09:45:37 -0500 (Mon, 08 Sep 2008) | 3 lines
Added xrefs to each other.
........
Diffstat (limited to 'Doc/library/2to3.rst')
-rw-r--r-- | Doc/library/2to3.rst | 49 |
1 files changed, 35 insertions, 14 deletions
diff --git a/Doc/library/2to3.rst b/Doc/library/2to3.rst index 99749b3..e8ea861 100644 --- a/Doc/library/2to3.rst +++ b/Doc/library/2to3.rst @@ -7,15 +7,21 @@ 2to3 is a Python program that reads Python 2.x source code and applies a series of *fixers* to transform it into valid Python 3.x code. The standard library -contains a rich set of fixers that will handle almost all code. It is, however, -possible to write your own fixers. +contains a rich set of fixers that will handle almost all code. 2to3 supporting +library :mod:`lib2to3` is, however, a flexible and generic library, so it is +possible to write your own fixers for 2to3. :mod:`lib2to3` could also be +adapted to custom applications in which Python code needs to be edited +automatically. Using 2to3 ---------- -2to3 can be run with a list of files to transform or a directory to recursively -traverse looking for files with the ``.py`` extension. +2to3 will usually be installed with the Python interpreter as a script. It is +also located in the :file:`Tools/scripts` directory of the Python root. + +2to3's basic arguments are a list of files or directories to transform. The +directories are to recursively traversed for Python sources. Here is a sample Python 2.x source file, :file:`example.py`:: @@ -29,13 +35,14 @@ It can be converted to Python 3.x code via 2to3 on the command line:: $ 2to3 example.py -A diff against the original source file will be printed. 2to3 can also write -the needed modifications right back to the source file. (A backup of the -original file will also be made.) This is done with the :option:`-w` flag:: +A diff against the original source file is printed. 2to3 can also write the +needed modifications right back to the source file. (Of course, a backup of the +original is also be made.) Writing the changes back is enabled with the +:option:`-w` flag:: $ 2to3 -w example.py -:file:`example.py` will now look like this:: +After transformation, :file:`example.py` looks like this:: def greet(name): print("Hello, {0}!".format(name)) @@ -43,10 +50,10 @@ original file will also be made.) This is done with the :option:`-w` flag:: name = input() greet(name) -Comments and and exact indentation will be preserved throughout the translation +Comments and and exact indentation are preserved throughout the translation process. -By default, 2to3 will run a set of predefined fixers. The :option:`-l` flag +By default, 2to3 runs a set of predefined fixers. The :option:`-l` flag lists all avaible fixers. An explicit set of fixers to run can be given by use of the :option:`-f` flag. The following example runs only the ``imports`` and ``has_key`` fixers:: @@ -54,16 +61,30 @@ of the :option:`-f` flag. The following example runs only the ``imports`` and $ 2to3 -f imports -f has_key example.py Some fixers are *explicit*, meaning they aren't run be default and must be -listed on the command line. Here, in addition to the default fixers, the -``idioms`` fixer is run:: +listed on the command line to be run. Here, in addition to the default fixers, +the ``idioms`` fixer is run:: $ 2to3 -f all -f idioms example.py -Notice how ``all`` enables all default fixers. +Notice how passing ``all`` enables all default fixers. Sometimes 2to3 will find will find a place in your source code that needs to be changed, but 2to3 cannot fix automatically. In this case, 2to3 will print a -warning beneath the diff for a file. +warning beneath the diff for a file. You should address the warning in order to +have compliant 3.x code. + +2to3 can also refactor doctests. To enable this mode, use the :option:`-d` +flag. Note that *only* doctests will be refactored. + +The :option:`-v` option enables the output of more information on the +translation process. + +When the :option:`-p` is passed to it, 2to3 treats ``print`` as a function +instead of a statement. This is useful when ``from __future__ import +print_function`` is being used. If this option is not given, the print fixer +will surround print calls in an extra set of parentheses because it cannot +differentiate between the and print statement with parentheses (such as ``print +("a" + "b" + "c")``) and a true function call. :mod:`lib2to3` - 2to3's library |