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      1 # Copyright 2006 Google, Inc. All Rights Reserved.
      2 # Licensed to PSF under a Contributor Agreement.
      3 
      4 """Fixer for apply().
      5 
      6 This converts apply(func, v, k) into (func)(*v, **k)."""
      7 
      8 # Local imports
      9 from .. import pytree
     10 from ..pgen2 import token
     11 from .. import fixer_base
     12 from ..fixer_util import Call, Comma, parenthesize
     13 
     14 class FixApply(fixer_base.BaseFix):
     15     BM_compatible = True
     16 
     17     PATTERN = """
     18     power< 'apply'
     19         trailer<
     20             '('
     21             arglist<
     22                 (not argument<NAME '=' any>) func=any ','
     23                 (not argument<NAME '=' any>) args=any [','
     24                 (not argument<NAME '=' any>) kwds=any] [',']
     25             >
     26             ')'
     27         >
     28     >
     29     """
     30 
     31     def transform(self, node, results):
     32         syms = self.syms
     33         assert results
     34         func = results["func"]
     35         args = results["args"]
     36         kwds = results.get("kwds")
     37         # I feel like we should be able to express this logic in the
     38         # PATTERN above but I don't know how to do it so...
     39         if args:
     40             if args.type == self.syms.star_expr:
     41                 return  # Make no change.
     42             if (args.type == self.syms.argument and
     43                 args.children[0].value == '**'):
     44                 return  # Make no change.
     45         if kwds and (kwds.type == self.syms.argument and
     46                      kwds.children[0].value == '**'):
     47             return  # Make no change.
     48         prefix = node.prefix
     49         func = func.clone()
     50         if (func.type not in (token.NAME, syms.atom) and
     51             (func.type != syms.power or
     52              func.children[-2].type == token.DOUBLESTAR)):
     53             # Need to parenthesize
     54             func = parenthesize(func)
     55         func.prefix = ""
     56         args = args.clone()
     57         args.prefix = ""
     58         if kwds is not None:
     59             kwds = kwds.clone()
     60             kwds.prefix = ""
     61         l_newargs = [pytree.Leaf(token.STAR, u"*"), args]
     62         if kwds is not None:
     63             l_newargs.extend([Comma(),
     64                               pytree.Leaf(token.DOUBLESTAR, u"**"),
     65                               kwds])
     66             l_newargs[-2].prefix = u" " # that's the ** token
     67         # XXX Sometimes we could be cleverer, e.g. apply(f, (x, y) + t)
     68         # can be translated into f(x, y, *t) instead of f(*(x, y) + t)
     69         #new = pytree.Node(syms.power, (func, ArgList(l_newargs)))
     70         return Call(func, l_newargs, prefix=prefix)
     71