cpython/Lib/lib2to3/fixes/fix_idioms.py

135 lines
3.9 KiB
Python

"""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, 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.set_prefix("")
T.set_prefix(" ")
test = Call(Name("isinstance"), [x, Comma(), T])
if "n" in results:
test.set_prefix(u" ")
test = Node(syms.not_test, [Name(u"not"), test])
test.set_prefix(node.get_prefix())
return test
def transform_while(self, node, results):
one = results["while"]
one.replace(Name(u"True", prefix=one.get_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(u"sorted", prefix=list_call.get_prefix()))
elif simple_expr:
new = simple_expr.clone()
new.set_prefix(u"")
simple_expr.replace(Call(Name(u"sorted"), [new],
prefix=simple_expr.get_prefix()))
else:
raise RuntimeError("should not have reached here")
sort_stmt.remove()
if next_stmt:
next_stmt[0].set_prefix(sort_stmt.get_prefix())