1 """Fixer that addes parentheses where they are required

     2 

     3 This converts ``[x for x in 1, 2]`` to ``[x for x in (1, 2)]``."""

     4 

     5 # By Taek Joo Kim and Benjamin Peterson

     6 

     7 # Local imports

     8 from .. import fixer_base

     9 from ..fixer_util import LParen, RParen

    10 

    11 # XXX This doesn't support nested for loops like [x for x in 1, 2 for x in 1, 2]

    12 class FixParen(fixer_base.BaseFix):

    13     PATTERN = """

    14         atom< ('[' | '(')

    15             (listmaker< any

    16                 comp_for<

    17                     'for' NAME 'in'

    18                     target=testlist_safe< any (',' any)+ [',']

    19                      >

    20                     [any]

    21                 >

    22             >

    23             |

    24             testlist_gexp< any

    25                 comp_for<

    26                     'for' NAME 'in'

    27                     target=testlist_safe< any (',' any)+ [',']

    28                      >

    29                     [any]

    30                 >

    31             >)

    32         (']' | ')') >

    33     """

    34 

    35     def transform(self, node, results):

    36         target = results["target"]

    37 

    38         lparen = LParen()

    39         lparen.set_prefix(target.get_prefix())

    40         target.set_prefix("") # Make it hug the parentheses

    41         target.insert_child(0, lparen)

    42         target.append_child(RParen())