/Lib/lib2to3/fixes/fix_dict.py

http://unladen-swallow.googlecode.com/ · Python · 99 lines · 56 code · 1 blank · 42 comment · 0 complexity · d12677f15a5a34c7754e90cb06bc153e MD5 · raw file

  1. # Copyright 2007 Google, Inc. All Rights Reserved.
  2. # Licensed to PSF under a Contributor Agreement.
  3. """Fixer for dict methods.
  4. d.keys() -> list(d.keys())
  5. d.items() -> list(d.items())
  6. d.values() -> list(d.values())
  7. d.iterkeys() -> iter(d.keys())
  8. d.iteritems() -> iter(d.items())
  9. d.itervalues() -> iter(d.values())
  10. Except in certain very specific contexts: the iter() can be dropped
  11. when the context is list(), sorted(), iter() or for...in; the list()
  12. can be dropped when the context is list() or sorted() (but not iter()
  13. or for...in!). Special contexts that apply to both: list(), sorted(), tuple()
  14. set(), any(), all(), sum().
  15. Note: iter(d.keys()) could be written as iter(d) but since the
  16. original d.iterkeys() was also redundant we don't fix this. And there
  17. are (rare) contexts where it makes a difference (e.g. when passing it
  18. as an argument to a function that introspects the argument).
  19. """
  20. # Local imports
  21. from .. import pytree
  22. from .. import patcomp
  23. from ..pgen2 import token
  24. from .. import fixer_base
  25. from ..fixer_util import Name, Call, LParen, RParen, ArgList, Dot
  26. from .. import fixer_util
  27. iter_exempt = fixer_util.consuming_calls | set(["iter"])
  28. class FixDict(fixer_base.BaseFix):
  29. PATTERN = """
  30. power< head=any+
  31. trailer< '.' method=('keys'|'items'|'values'|
  32. 'iterkeys'|'iteritems'|'itervalues') >
  33. parens=trailer< '(' ')' >
  34. tail=any*
  35. >
  36. """
  37. def transform(self, node, results):
  38. head = results["head"]
  39. method = results["method"][0] # Extract node for method name
  40. tail = results["tail"]
  41. syms = self.syms
  42. method_name = method.value
  43. isiter = method_name.startswith("iter")
  44. if isiter:
  45. method_name = method_name[4:]
  46. assert method_name in ("keys", "items", "values"), repr(method)
  47. head = [n.clone() for n in head]
  48. tail = [n.clone() for n in tail]
  49. special = not tail and self.in_special_context(node, isiter)
  50. args = head + [pytree.Node(syms.trailer,
  51. [Dot(),
  52. Name(method_name,
  53. prefix=method.get_prefix())]),
  54. results["parens"].clone()]
  55. new = pytree.Node(syms.power, args)
  56. if not special:
  57. new.set_prefix("")
  58. new = Call(Name(isiter and "iter" or "list"), [new])
  59. if tail:
  60. new = pytree.Node(syms.power, [new] + tail)
  61. new.set_prefix(node.get_prefix())
  62. return new
  63. P1 = "power< func=NAME trailer< '(' node=any ')' > any* >"
  64. p1 = patcomp.compile_pattern(P1)
  65. P2 = """for_stmt< 'for' any 'in' node=any ':' any* >
  66. | comp_for< 'for' any 'in' node=any any* >
  67. """
  68. p2 = patcomp.compile_pattern(P2)
  69. def in_special_context(self, node, isiter):
  70. if node.parent is None:
  71. return False
  72. results = {}
  73. if (node.parent.parent is not None and
  74. self.p1.match(node.parent.parent, results) and
  75. results["node"] is node):
  76. if isiter:
  77. # iter(d.iterkeys()) -> iter(d.keys()), etc.
  78. return results["func"].value in iter_exempt
  79. else:
  80. # list(d.keys()) -> list(d.keys()), etc.
  81. return results["func"].value in fixer_util.consuming_calls
  82. if not isiter:
  83. return False
  84. # for ... in d.iterkeys() -> for ... in d.keys(), etc.
  85. return self.p2.match(node.parent, results) and results["node"] is node