| 4710c53d |
1 | """Fixer for it.next() -> next(it), per PEP 3114."""\r |
| 2 | # Author: Collin Winter\r |
| 3 | \r |
| 4 | # Things that currently aren't covered:\r |
| 5 | # - listcomp "next" names aren't warned\r |
| 6 | # - "with" statement targets aren't checked\r |
| 7 | \r |
| 8 | # Local imports\r |
| 9 | from ..pgen2 import token\r |
| 10 | from ..pygram import python_symbols as syms\r |
| 11 | from .. import fixer_base\r |
| 12 | from ..fixer_util import Name, Call, find_binding\r |
| 13 | \r |
| 14 | bind_warning = "Calls to builtin next() possibly shadowed by global binding"\r |
| 15 | \r |
| 16 | \r |
| 17 | class FixNext(fixer_base.BaseFix):\r |
| 18 | BM_compatible = True\r |
| 19 | PATTERN = """\r |
| 20 | power< base=any+ trailer< '.' attr='next' > trailer< '(' ')' > >\r |
| 21 | |\r |
| 22 | power< head=any+ trailer< '.' attr='next' > not trailer< '(' ')' > >\r |
| 23 | |\r |
| 24 | classdef< 'class' any+ ':'\r |
| 25 | suite< any*\r |
| 26 | funcdef< 'def'\r |
| 27 | name='next'\r |
| 28 | parameters< '(' NAME ')' > any+ >\r |
| 29 | any* > >\r |
| 30 | |\r |
| 31 | global=global_stmt< 'global' any* 'next' any* >\r |
| 32 | """\r |
| 33 | \r |
| 34 | order = "pre" # Pre-order tree traversal\r |
| 35 | \r |
| 36 | def start_tree(self, tree, filename):\r |
| 37 | super(FixNext, self).start_tree(tree, filename)\r |
| 38 | \r |
| 39 | n = find_binding(u'next', tree)\r |
| 40 | if n:\r |
| 41 | self.warning(n, bind_warning)\r |
| 42 | self.shadowed_next = True\r |
| 43 | else:\r |
| 44 | self.shadowed_next = False\r |
| 45 | \r |
| 46 | def transform(self, node, results):\r |
| 47 | assert results\r |
| 48 | \r |
| 49 | base = results.get("base")\r |
| 50 | attr = results.get("attr")\r |
| 51 | name = results.get("name")\r |
| 52 | \r |
| 53 | if base:\r |
| 54 | if self.shadowed_next:\r |
| 55 | attr.replace(Name(u"__next__", prefix=attr.prefix))\r |
| 56 | else:\r |
| 57 | base = [n.clone() for n in base]\r |
| 58 | base[0].prefix = u""\r |
| 59 | node.replace(Call(Name(u"next", prefix=node.prefix), base))\r |
| 60 | elif name:\r |
| 61 | n = Name(u"__next__", prefix=name.prefix)\r |
| 62 | name.replace(n)\r |
| 63 | elif attr:\r |
| 64 | # We don't do this transformation if we're assigning to "x.next".\r |
| 65 | # Unfortunately, it doesn't seem possible to do this in PATTERN,\r |
| 66 | # so it's being done here.\r |
| 67 | if is_assign_target(node):\r |
| 68 | head = results["head"]\r |
| 69 | if "".join([str(n) for n in head]).strip() == u'__builtin__':\r |
| 70 | self.warning(node, bind_warning)\r |
| 71 | return\r |
| 72 | attr.replace(Name(u"__next__"))\r |
| 73 | elif "global" in results:\r |
| 74 | self.warning(node, bind_warning)\r |
| 75 | self.shadowed_next = True\r |
| 76 | \r |
| 77 | \r |
| 78 | ### The following functions help test if node is part of an assignment\r |
| 79 | ### target.\r |
| 80 | \r |
| 81 | def is_assign_target(node):\r |
| 82 | assign = find_assign(node)\r |
| 83 | if assign is None:\r |
| 84 | return False\r |
| 85 | \r |
| 86 | for child in assign.children:\r |
| 87 | if child.type == token.EQUAL:\r |
| 88 | return False\r |
| 89 | elif is_subtree(child, node):\r |
| 90 | return True\r |
| 91 | return False\r |
| 92 | \r |
| 93 | def find_assign(node):\r |
| 94 | if node.type == syms.expr_stmt:\r |
| 95 | return node\r |
| 96 | if node.type == syms.simple_stmt or node.parent is None:\r |
| 97 | return None\r |
| 98 | return find_assign(node.parent)\r |
| 99 | \r |
| 100 | def is_subtree(root, node):\r |
| 101 | if root == node:\r |
| 102 | return True\r |
| 103 | return any(is_subtree(c, node) for c in root.children)\r |
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