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diff --git a/Doc/library/2to3.rst b/Doc/library/2to3.rst new file mode 100644 index 0000000..4d64af8 --- /dev/null +++ b/Doc/library/2to3.rst @@ -0,0 +1,75 @@ +.. _2to3-reference: + +2to3 - Automated Python 2 to 3 code translation +=============================================== + +.. sectionauthor:: Benjamin Peterson + +2to3 is a Python program that reads your Python 2.x source code and applies a +series of *fixers* to transform it into valid Python 3.x code. + + +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. + +Here is a sample Python 2.x source file, :file:`example.py`:: + + def greet(name): + print "Hello, {0}!".format(name) + print "What's your name?" + name = raw_input() + greet(name) + +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:: + + $ 2to3 -w example.py + +:file:`example.py` will now look like this:: + + def greet(name): + print("Hello, {0}!".format(name)) + print("What's your name?") + name = input() + greet(name) + +Comments and and exact indentation will be preserved throughout the translation +process. + +By default, 2to3 will run 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:: + + $ 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:: + + $ 2to3 -f all -f idioms example.py + +Notice how ``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. + + +:mod:`lib2to3` - 2to3's library +------------------------------- + +.. module:: lib2to3 + :synopsis: the 2to3 library +.. moduleauthor:: Guido van Rossum +.. moduleauthor:: Collin Winter + +.. XXX What is the public interface anyway? |