cpython/Lib/lib2to3/fixes/fix_next.py
Benjamin Peterson 6ae94ee299 Merged revisions 66805,66841,66860,66884-66886,66893,66907,66910 via svnmerge from
svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3

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  r66805 | benjamin.peterson | 2008-10-04 20:11:02 -0500 (Sat, 04 Oct 2008) | 1 line

  mention what the fixes directory is for
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  r66841 | benjamin.peterson | 2008-10-07 17:48:12 -0500 (Tue, 07 Oct 2008) | 1 line

  use assertFalse and assertTrue
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  r66860 | benjamin.peterson | 2008-10-08 16:05:07 -0500 (Wed, 08 Oct 2008) | 1 line

  instead of abusing the pattern matcher, use start_tree to find a next binding
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  r66884 | benjamin.peterson | 2008-10-13 15:50:30 -0500 (Mon, 13 Oct 2008) | 1 line

  don't print tokens to stdout when -v is given
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  r66885 | benjamin.peterson | 2008-10-13 16:28:57 -0500 (Mon, 13 Oct 2008) | 1 line

  add the -x option to disable fixers
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  r66886 | benjamin.peterson | 2008-10-13 16:33:53 -0500 (Mon, 13 Oct 2008) | 1 line

  cut down on some crud
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  r66893 | benjamin.peterson | 2008-10-14 17:16:54 -0500 (Tue, 14 Oct 2008) | 1 line

  add an optional set literal fixer
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  r66907 | benjamin.peterson | 2008-10-15 16:59:41 -0500 (Wed, 15 Oct 2008) | 1 line

  don't write backup files by default
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  r66910 | benjamin.peterson | 2008-10-15 17:43:10 -0500 (Wed, 15 Oct 2008) | 1 line

  add the -n option; it stops backupfiles from being written
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2008-10-15 23:10:28 +00:00

103 lines
3.1 KiB
Python

"""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, any
bind_warning = "Calls to builtin next() possibly shadowed by global binding"
class FixNext(fixer_base.BaseFix):
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")
mod = results.get("mod")
if base:
if self.shadowed_next:
attr.replace(Name("__next__", prefix=attr.get_prefix()))
else:
base = [n.clone() for n in base]
base[0].set_prefix("")
node.replace(Call(Name("next", prefix=node.get_prefix()), base))
elif name:
n = Name("__next__", prefix=name.get_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])