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| """Fixer for it.next() -> next(it), per PEP 3114.""" | |
| # Author: Collin Winter | |
| # Things that currently aren't covered: | |
| # - listcomp "next" names aren't warned | |
| # - "with" statement targets aren't checked | |
| # Local imports | |
| from ..pgen2 import token | |
| from ..pygram import python_symbols as syms | |
| from .. import fixer_base | |
| from ..fixer_util import Name, Call, find_binding | |
| bind_warning = "Calls to builtin next() possibly shadowed by global binding" | |
| class FixNext(fixer_base.BaseFix): | |
| BM_compatible = True | |
| PATTERN = """ | |
| power< base=any+ trailer< '.' attr='next' > trailer< '(' ')' > > | |
| | | |
| power< head=any+ trailer< '.' attr='next' > not trailer< '(' ')' > > | |
| | | |
| classdef< 'class' any+ ':' | |
| suite< any* | |
| funcdef< 'def' | |
| name='next' | |
| parameters< '(' NAME ')' > any+ > | |
| any* > > | |
| | | |
| global=global_stmt< 'global' any* 'next' any* > | |
| """ | |
| order = "pre" # Pre-order tree traversal | |
| def start_tree(self, tree, filename): | |
| super(FixNext, self).start_tree(tree, filename) | |
| n = find_binding('next', tree) | |
| if n: | |
| self.warning(n, bind_warning) | |
| self.shadowed_next = True | |
| else: | |
| self.shadowed_next = False | |
| def transform(self, node, results): | |
| assert results | |
| base = results.get("base") | |
| attr = results.get("attr") | |
| name = results.get("name") | |
| if base: | |
| if self.shadowed_next: | |
| attr.replace(Name("__next__", prefix=attr.prefix)) | |
| else: | |
| base = [n.clone() for n in base] | |
| base[0].prefix = "" | |
| node.replace(Call(Name("next", prefix=node.prefix), base)) | |
| elif name: | |
| n = Name("__next__", prefix=name.prefix) | |
| name.replace(n) | |
| elif attr: | |
| # We don't do this transformation if we're assigning to "x.next". | |
| # Unfortunately, it doesn't seem possible to do this in PATTERN, | |
| # so it's being done here. | |
| if is_assign_target(node): | |
| head = results["head"] | |
| if "".join([str(n) for n in head]).strip() == '__builtin__': | |
| self.warning(node, bind_warning) | |
| return | |
| attr.replace(Name("__next__")) | |
| elif "global" in results: | |
| self.warning(node, bind_warning) | |
| self.shadowed_next = True | |
| ### The following functions help test if node is part of an assignment | |
| ### target. | |
| def is_assign_target(node): | |
| assign = find_assign(node) | |
| if assign is None: | |
| return False | |
| for child in assign.children: | |
| if child.type == token.EQUAL: | |
| return False | |
| elif is_subtree(child, node): | |
| return True | |
| return False | |
| def find_assign(node): | |
| if node.type == syms.expr_stmt: | |
| return node | |
| if node.type == syms.simple_stmt or node.parent is None: | |
| return None | |
| return find_assign(node.parent) | |
| def is_subtree(root, node): | |
| if root == node: | |
| return True | |
| return any(is_subtree(c, node) for c in root.children) | |