1  # Copyright 2007 Google, Inc. All Rights Reserved.
       2  # Licensed to PSF under a Contributor Agreement.
       3  
       4  """Fixer for dict methods.
       5  
       6  d.keys() -> list(d.keys())
       7  d.items() -> list(d.items())
       8  d.values() -> list(d.values())
       9  
      10  d.iterkeys() -> iter(d.keys())
      11  d.iteritems() -> iter(d.items())
      12  d.itervalues() -> iter(d.values())
      13  
      14  d.viewkeys() -> d.keys()
      15  d.viewitems() -> d.items()
      16  d.viewvalues() -> d.values()
      17  
      18  Except in certain very specific contexts: the iter() can be dropped
      19  when the context is list(), sorted(), iter() or for...in; the list()
      20  can be dropped when the context is list() or sorted() (but not iter()
      21  or for...in!). Special contexts that apply to both: list(), sorted(), tuple()
      22  set(), any(), all(), sum().
      23  
      24  Note: iter(d.keys()) could be written as iter(d) but since the
      25  original d.iterkeys() was also redundant we don't fix this.  And there
      26  are (rare) contexts where it makes a difference (e.g. when passing it
      27  as an argument to a function that introspects the argument).
      28  """
      29  
      30  # Local imports
      31  from .. import pytree
      32  from .. import patcomp
      33  from .. import fixer_base
      34  from ..fixer_util import Name, Call, Dot
      35  from .. import fixer_util
      36  
      37  
      38  iter_exempt = fixer_util.consuming_calls | {"iter"}
      39  
      40  
      41  class ESC[4;38;5;81mFixDict(ESC[4;38;5;149mfixer_baseESC[4;38;5;149m.ESC[4;38;5;149mBaseFix):
      42      BM_compatible = True
      43  
      44      PATTERN = """
      45      power< head=any+
      46           trailer< '.' method=('keys'|'items'|'values'|
      47                                'iterkeys'|'iteritems'|'itervalues'|
      48                                'viewkeys'|'viewitems'|'viewvalues') >
      49           parens=trailer< '(' ')' >
      50           tail=any*
      51      >
      52      """
      53  
      54      def transform(self, node, results):
      55          head = results["head"]
      56          method = results["method"][0] # Extract node for method name
      57          tail = results["tail"]
      58          syms = self.syms
      59          method_name = method.value
      60          isiter = method_name.startswith("iter")
      61          isview = method_name.startswith("view")
      62          if isiter or isview:
      63              method_name = method_name[4:]
      64          assert method_name in ("keys", "items", "values"), repr(method)
      65          head = [n.clone() for n in head]
      66          tail = [n.clone() for n in tail]
      67          special = not tail and self.in_special_context(node, isiter)
      68          args = head + [pytree.Node(syms.trailer,
      69                                     [Dot(),
      70                                      Name(method_name,
      71                                           prefix=method.prefix)]),
      72                         results["parens"].clone()]
      73          new = pytree.Node(syms.power, args)
      74          if not (special or isview):
      75              new.prefix = ""
      76              new = Call(Name("iter" if isiter else "list"), [new])
      77          if tail:
      78              new = pytree.Node(syms.power, [new] + tail)
      79          new.prefix = node.prefix
      80          return new
      81  
      82      P1 = "power< func=NAME trailer< '(' node=any ')' > any* >"
      83      p1 = patcomp.compile_pattern(P1)
      84  
      85      P2 = """for_stmt< 'for' any 'in' node=any ':' any* >
      86              | comp_for< 'for' any 'in' node=any any* >
      87           """
      88      p2 = patcomp.compile_pattern(P2)
      89  
      90      def in_special_context(self, node, isiter):
      91          if node.parent is None:
      92              return False
      93          results = {}
      94          if (node.parent.parent is not None and
      95                 self.p1.match(node.parent.parent, results) and
      96                 results["node"] is node):
      97              if isiter:
      98                  # iter(d.iterkeys()) -> iter(d.keys()), etc.
      99                  return results["func"].value in iter_exempt
     100              else:
     101                  # list(d.keys()) -> list(d.keys()), etc.
     102                  return results["func"].value in fixer_util.consuming_calls
     103          if not isiter:
     104              return False
     105          # for ... in d.iterkeys() -> for ... in d.keys(), etc.
     106          return self.p2.match(node.parent, results) and results["node"] is node