Current File : //opt/alt/python37/lib64/python3.7/lib2to3/fixes/fix_idioms.py
"""Adjust some old Python 2 idioms to their modern counterparts.
* Change some type comparisons to isinstance() calls:
type(x) == T -> isinstance(x, T)
type(x) is T -> isinstance(x, T)
type(x) != T -> not isinstance(x, T)
type(x) is not T -> not isinstance(x, T)
* Change "while 1:" into "while True:".
* Change both
v = list(EXPR)
v.sort()
foo(v)
and the more general
v = EXPR
v.sort()
foo(v)
into
v = sorted(EXPR)
foo(v)
"""
# Author: Jacques Frechet, Collin Winter
# Local imports
from .. import fixer_base
from ..fixer_util import Call, Comma, Name, Node, BlankLine, syms
CMP = "(n='!=' | '==' | 'is' | n=comp_op< 'is' 'not' >)"
TYPE = "power< 'type' trailer< '(' x=any ')' > >"
class FixIdioms(fixer_base.BaseFix):
explicit = True # The user must ask for this fixer
PATTERN = r"""
isinstance=comparison< %s %s T=any >
|
isinstance=comparison< T=any %s %s >
|
while_stmt< 'while' while='1' ':' any+ >
|
sorted=any<
any*
simple_stmt<
expr_stmt< id1=any '='
power< list='list' trailer< '(' (not arglist<any+>) any ')' > >
>
'\n'
>
sort=
simple_stmt<
power< id2=any
trailer< '.' 'sort' > trailer< '(' ')' >
>
'\n'
>
next=any*
>
|
sorted=any<
any*
simple_stmt< expr_stmt< id1=any '=' expr=any > '\n' >
sort=
simple_stmt<
power< id2=any
trailer< '.' 'sort' > trailer< '(' ')' >
>
'\n'
>
next=any*
>
""" % (TYPE, CMP, CMP, TYPE)
def match(self, node):
r = super(FixIdioms, self).match(node)
# If we've matched one of the sort/sorted subpatterns above, we
# want to reject matches where the initial assignment and the
# subsequent .sort() call involve different identifiers.
if r and "sorted" in r:
if r["id1"] == r["id2"]:
return r
return None
return r
def transform(self, node, results):
if "isinstance" in results:
return self.transform_isinstance(node, results)
elif "while" in results:
return self.transform_while(node, results)
elif "sorted" in results:
return self.transform_sort(node, results)
else:
raise RuntimeError("Invalid match")
def transform_isinstance(self, node, results):
x = results["x"].clone() # The thing inside of type()
T = results["T"].clone() # The type being compared against
x.prefix = ""
T.prefix = " "
test = Call(Name("isinstance"), [x, Comma(), T])
if "n" in results:
test.prefix = " "
test = Node(syms.not_test, [Name("not"), test])
test.prefix = node.prefix
return test
def transform_while(self, node, results):
one = results["while"]
one.replace(Name("True", prefix=one.prefix))
def transform_sort(self, node, results):
sort_stmt = results["sort"]
next_stmt = results["next"]
list_call = results.get("list")
simple_expr = results.get("expr")
if list_call:
list_call.replace(Name("sorted", prefix=list_call.prefix))
elif simple_expr:
new = simple_expr.clone()
new.prefix = ""
simple_expr.replace(Call(Name("sorted"), [new],
prefix=simple_expr.prefix))
else:
raise RuntimeError("should not have reached here")
sort_stmt.remove()
btwn = sort_stmt.prefix
# Keep any prefix lines between the sort_stmt and the list_call and
# shove them right after the sorted() call.
if "\n" in btwn:
if next_stmt:
# The new prefix should be everything from the sort_stmt's
# prefix up to the last newline, then the old prefix after a new
# line.
prefix_lines = (btwn.rpartition("\n")[0], next_stmt[0].prefix)
next_stmt[0].prefix = "\n".join(prefix_lines)
else:
assert list_call.parent
assert list_call.next_sibling is None
# Put a blank line after list_call and set its prefix.
end_line = BlankLine()
list_call.parent.append_child(end_line)
assert list_call.next_sibling is end_line
# The new prefix should be everything up to the first new line
# of sort_stmt's prefix.
end_line.prefix = btwn.rpartition("\n")[0]
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