Current File : //usr/lib64/python2.7/lib2to3/fixes/fix_has_key.py
# Copyright 2006 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.
"""Fixer for has_key().
Calls to .has_key() methods are expressed in terms of the 'in'
operator:
d.has_key(k) -> k in d
CAVEATS:
1) While the primary target of this fixer is dict.has_key(), the
fixer will change any has_key() method call, regardless of its
class.
2) Cases like this will not be converted:
m = d.has_key
if m(k):
...
Only *calls* to has_key() are converted. While it is possible to
convert the above to something like
m = d.__contains__
if m(k):
...
this is currently not done.
"""
# Local imports
from .. import pytree
from ..pgen2 import token
from .. import fixer_base
from ..fixer_util import Name, parenthesize
class FixHasKey(fixer_base.BaseFix):
BM_compatible = True
PATTERN = """
anchor=power<
before=any+
trailer< '.' 'has_key' >
trailer<
'('
( not(arglist | argument<any '=' any>) arg=any
| arglist<(not argument<any '=' any>) arg=any ','>
)
')'
>
after=any*
>
|
negation=not_test<
'not'
anchor=power<
before=any+
trailer< '.' 'has_key' >
trailer<
'('
( not(arglist | argument<any '=' any>) arg=any
| arglist<(not argument<any '=' any>) arg=any ','>
)
')'
>
>
>
"""
def transform(self, node, results):
assert results
syms = self.syms
if (node.parent.type == syms.not_test and
self.pattern.match(node.parent)):
# Don't transform a node matching the first alternative of the
# pattern when its parent matches the second alternative
return None
negation = results.get("negation")
anchor = results["anchor"]
prefix = node.prefix
before = [n.clone() for n in results["before"]]
arg = results["arg"].clone()
after = results.get("after")
if after:
after = [n.clone() for n in after]
if arg.type in (syms.comparison, syms.not_test, syms.and_test,
syms.or_test, syms.test, syms.lambdef, syms.argument):
arg = parenthesize(arg)
if len(before) == 1:
before = before[0]
else:
before = pytree.Node(syms.power, before)
before.prefix = u" "
n_op = Name(u"in", prefix=u" ")
if negation:
n_not = Name(u"not", prefix=u" ")
n_op = pytree.Node(syms.comp_op, (n_not, n_op))
new = pytree.Node(syms.comparison, (arg, n_op, before))
if after:
new = parenthesize(new)
new = pytree.Node(syms.power, (new,) + tuple(after))
if node.parent.type in (syms.comparison, syms.expr, syms.xor_expr,
syms.and_expr, syms.shift_expr,
syms.arith_expr, syms.term,
syms.factor, syms.power):
new = parenthesize(new)
new.prefix = prefix
return new
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