cpython/Lib/lib2to3/fixes/fix_paren.py

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2010-02-05 22:40:03 -04:00
"""Fixer that addes parentheses where they are required
This converts ``[x for x in 1, 2]`` to ``[x for x in (1, 2)]``."""
# By Taek Joo Kim and Benjamin Peterson
# Local imports
from .. import fixer_base
from ..fixer_util import LParen, RParen
# XXX This doesn't support nested for loops like [x for x in 1, 2 for x in 1, 2]
class FixParen(fixer_base.BaseFix):
PATTERN = """
atom< ('[' | '(')
(listmaker< any
comp_for<
'for' NAME 'in'
target=testlist_safe< any (',' any)+ [',']
>
[any]
>
>
|
testlist_gexp< any
comp_for<
'for' NAME 'in'
target=testlist_safe< any (',' any)+ [',']
>
[any]
>
>)
(']' | ')') >
"""
def transform(self, node, results):
target = results["target"]
lparen = LParen()
lparen.prefix = target.prefix
target.prefix = u"" # Make it hug the parentheses
target.insert_child(0, lparen)
target.append_child(RParen())