Current File : //snap/core20/2318/lib/python3.8/lib2to3/fixes/fix_filter.py
# Copyright 2007 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.
"""Fixer that changes filter(F, X) into list(filter(F, X)).
We avoid the transformation if the filter() call is directly contained
in iter(<>), list(<>), tuple(<>), sorted(<>), ...join(<>), or
for V in <>:.
NOTE: This is still not correct if the original code was depending on
filter(F, X) to return a string if X is a string and a tuple if X is a
tuple. That would require type inference, which we don't do. Let
Python 2.6 figure it out.
"""
# Local imports
from .. import fixer_base
from ..pytree import Node
from ..pygram import python_symbols as syms
from ..fixer_util import Name, ArgList, ListComp, in_special_context, parenthesize
class FixFilter(fixer_base.ConditionalFix):
BM_compatible = True
PATTERN = """
filter_lambda=power<
'filter'
trailer<
'('
arglist<
lambdef< 'lambda'
(fp=NAME | vfpdef< '(' fp=NAME ')'> ) ':' xp=any
>
','
it=any
>
')'
>
[extra_trailers=trailer*]
>
|
power<
'filter'
trailer< '(' arglist< none='None' ',' seq=any > ')' >
[extra_trailers=trailer*]
>
|
power<
'filter'
args=trailer< '(' [any] ')' >
[extra_trailers=trailer*]
>
"""
skip_on = "future_builtins.filter"
def transform(self, node, results):
if self.should_skip(node):
return
trailers = []
if 'extra_trailers' in results:
for t in results['extra_trailers']:
trailers.append(t.clone())
if "filter_lambda" in results:
xp = results.get("xp").clone()
if xp.type == syms.test:
xp.prefix = ""
xp = parenthesize(xp)
new = ListComp(results.get("fp").clone(),
results.get("fp").clone(),
results.get("it").clone(), xp)
new = Node(syms.power, [new] + trailers, prefix="")
elif "none" in results:
new = ListComp(Name("_f"),
Name("_f"),
results["seq"].clone(),
Name("_f"))
new = Node(syms.power, [new] + trailers, prefix="")
else:
if in_special_context(node):
return None
args = results['args'].clone()
new = Node(syms.power, [Name("filter"), args], prefix="")
new = Node(syms.power, [Name("list"), ArgList([new])] + trailers)
new.prefix = ""
new.prefix = node.prefix
return new
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