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Clarify the transition plan for the 2to3 fixer. Also link directly to the 

fixer itself.
This commit is contained in:
Brett Cannon 2007-03-20 21:47:44 +00:00
parent 1c68c46409
commit 34e9d0f39f
1 changed files with 20 additions and 7 deletions
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27
pep-3113.txt
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@ -216,13 +216,12 @@ emitted when Python's compiler comes across a tuple parameter in
Python 2.6. This will be treated like any other syntactic change that Python 2.6. This will be treated like any other syntactic change that
is to occur in Python 3.0 compared to Python 2.6. is to occur in Python 3.0 compared to Python 2.6.
Second, the 2to3 refactoring tool [#2to3]_ will gain a rule for Second, the 2to3 refactoring tool [#2to3]_ will gain a fixer
translating tuple parameters to being a single parameter that is [#fixer]_ for translating tuple parameters to being a single parameter
unpacked as the first statement in the function. The name of the new that is unpacked as the first statement in the function. The name of
parameter will be a mangling of tuple parameter's names by joining the new parameter will be changed. The new parameter will then be
them with underscores. The new parameter will then be unpacked into unpacked into the names originally used in the tuple parameter. This
the names originally used in the tuple parameter. This means that the means that the following function::
following function::
def fxn((a, (b, c))): def fxn((a, (b, c))):
pass pass
@ -233,6 +232,17 @@ will be translated into::
(a, (b, c)) = a_b_c (a, (b, c)) = a_b_c
pass pass
As tuple parameters are used by lambdas because of the single
expression limitation, they must also be supported. This is done by
having the expected sequence argument bound to a single parameter and
then indexing on that parameter::
lambda (x, y): x + y
will be translated into::
lambda x_y: x_y[0] + x_y[1]
References References
========== ==========
@ -240,6 +250,9 @@ References
.. [#2to3] 2to3 refactoring tool .. [#2to3] 2to3 refactoring tool
(http://svn.python.org/view/sandbox/trunk/2to3/) (http://svn.python.org/view/sandbox/trunk/2to3/)
.. [#fixer] 2to3 fixer
(http://svn.python.org/view/sandbox/trunk/2to3/fixes/fix_tuple_params.py)
.. [#ironpython] IronPython .. [#ironpython] IronPython
(http://www.codeplex.com/Wiki/View.aspx?ProjectName=IronPython) (http://www.codeplex.com/Wiki/View.aspx?ProjectName=IronPython)