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bpo-28837: Fix lib2to3 handling of map/zip/filter calls when followed with a 'trailer', e.g. zip()[x] (#24)

This commit is contained in:
Stuart Berg 2017-04-06 01:19:40 -04:00 committed by Benjamin Peterson
parent 01fa9ae546
commit 93b4b47e3a
5 changed files with 110 additions and 26 deletions
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21
Lib/lib2to3/fixes/fix_filter.py
View File

@ -15,7 +15,10 @@ Python 2.6 figure it out.
# Local imports
from .. import fixer_base
from ..fixer_util import Name, Call, ListComp, in_special_context
from ..pytree import Node
from ..pygram import python_symbols as syms
from ..fixer_util import Name, ArgList, ListComp, in_special_context
class FixFilter(fixer_base.ConditionalFix):
BM_compatible = True
@ -34,16 +37,19 @@ class FixFilter(fixer_base.ConditionalFix):
>
')'
>
[extra_trailers=trailer*]
>
|
power<
'filter'
trailer< '(' arglist< none='None' ',' seq=any > ')' >
[extra_trailers=trailer*]
>
|
power<
'filter'
args=trailer< '(' [any] ')' >
[extra_trailers=trailer*]
>
"""
@ -53,23 +59,32 @@ class FixFilter(fixer_base.ConditionalFix):
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:
new = ListComp(results.get("fp").clone(),
results.get("fp").clone(),
results.get("it").clone(),
results.get("xp").clone())
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
new = node.clone()
args = results['args'].clone()
new = Node(syms.power, [Name("filter"), args], prefix="")
new = Node(syms.power, [Name("list"), ArgList([new])] + trailers)
new.prefix = ""
new = Call(Name("list"), [new])
new.prefix = node.prefix
return new

37
Lib/lib2to3/fixes/fix_map.py
View File

@ -22,8 +22,10 @@ soon as the shortest argument is exhausted.
# Local imports
from ..pgen2 import token
from .. import fixer_base
from ..fixer_util import Name, Call, ListComp, in_special_context
from ..fixer_util import Name, ArgList, Call, ListComp, in_special_context
from ..pygram import python_symbols as syms
from ..pytree import Node
class FixMap(fixer_base.ConditionalFix):
BM_compatible = True
@ -32,6 +34,7 @@ class FixMap(fixer_base.ConditionalFix):
map_none=power<
'map'
trailer< '(' arglist< 'None' ',' arg=any [','] > ')' >
[extra_trailers=trailer*]
>
|
map_lambda=power<
@ -47,10 +50,12 @@ class FixMap(fixer_base.ConditionalFix):
>
')'
>
[extra_trailers=trailer*]
>
|
power<
'map' trailer< '(' [arglist=any] ')' >
'map' args=trailer< '(' [any] ')' >
[extra_trailers=trailer*]
>
"""
@ -60,6 +65,11 @@ class FixMap(fixer_base.ConditionalFix):
if self.should_skip(node):
return
trailers = []
if 'extra_trailers' in results:
for t in results['extra_trailers']:
trailers.append(t.clone())
if node.parent.type == syms.simple_stmt:
self.warning(node, "You should use a for loop here")
new = node.clone()
@ -69,23 +79,32 @@ class FixMap(fixer_base.ConditionalFix):
new = ListComp(results["xp"].clone(),
results["fp"].clone(),
results["it"].clone())
new = Node(syms.power, [new] + trailers, prefix="")
else:
if "map_none" in results:
new = results["arg"].clone()
new.prefix = ""
else:
if "arglist" in results:
args = results["arglist"]
if args.type == syms.arglist and \
args.children[0].type == token.NAME and \
args.children[0].value == "None":
if "args" in results:
args = results["args"]
if args.type == syms.trailer and \
args.children[1].type == syms.arglist and \
args.children[1].children[0].type == token.NAME and \
args.children[1].children[0].value == "None":
self.warning(node, "cannot convert map(None, ...) "
"with multiple arguments because map() "
"now truncates to the shortest sequence")
return
new = Node(syms.power, [Name("map"), args.clone()])
new.prefix = ""
if in_special_context(node):
return None
new = node.clone()
new = Node(syms.power, [Name("list"), ArgList([new])] + trailers)
new.prefix = ""
new = Call(Name("list"), [new])
new.prefix = node.prefix
return new

21
Lib/lib2to3/fixes/fix_zip.py
View File

@ -9,13 +9,16 @@ iter(<>), list(<>), tuple(<>), sorted(<>), ...join(<>), or for V in <>:.
# Local imports
from .. import fixer_base
from ..fixer_util import Name, Call, in_special_context
from ..pytree import Node
from ..pygram import python_symbols as syms
from ..fixer_util import Name, ArgList, in_special_context
class FixZip(fixer_base.ConditionalFix):
BM_compatible = True
PATTERN = """
power< 'zip' args=trailer< '(' [any] ')' >
power< 'zip' args=trailer< '(' [any] ')' > [trailers=trailer*]
>
"""
@ -28,8 +31,16 @@ class FixZip(fixer_base.ConditionalFix):
if in_special_context(node):
return None
new = node.clone()
new.prefix = ""
new = Call(Name("list"), [new])
args = results['args'].clone()
args.prefix = ""
trailers = []
if 'trailers' in results:
trailers = [n.clone() for n in results['trailers']]
for n in trailers:
n.prefix = ""
new = Node(syms.power, [Name("zip"), args], prefix="")
new = Node(syms.power, [Name("list"), ArgList([new])] + trailers)
new.prefix = node.prefix
return new

56
Lib/lib2to3/tests/test_fixers.py
View File

@ -2954,10 +2954,23 @@ class Test_filter(FixerTestCase):
a = """x = [x for x in range(10) if x%2 == 0]"""
self.check(b, a)
# XXX This (rare) case is not supported
## b = """x = filter(f, 'abc')[0]"""
## a = """x = list(filter(f, 'abc'))[0]"""
## self.check(b, a)
def test_filter_trailers(self):
b = """x = filter(None, 'abc')[0]"""
a = """x = [_f for _f in 'abc' if _f][0]"""
self.check(b, a)
b = """x = len(filter(f, 'abc')[0])"""
a = """x = len(list(filter(f, 'abc'))[0])"""
self.check(b, a)
b = """x = filter(lambda x: x%2 == 0, range(10))[0]"""
a = """x = [x for x in range(10) if x%2 == 0][0]"""
self.check(b, a)
# Note the parens around x
b = """x = filter(lambda (x): x%2 == 0, range(10))[0]"""
a = """x = [x for x in range(10) if x%2 == 0][0]"""
self.check(b, a)
def test_filter_nochange(self):
a = """b.join(filter(f, 'abc'))"""
@ -3022,6 +3035,23 @@ class Test_map(FixerTestCase):
a = """x = list(map( f, 'abc' ))"""
self.check(b, a)
def test_map_trailers(self):
b = """x = map(f, 'abc')[0]"""
a = """x = list(map(f, 'abc'))[0]"""
self.check(b, a)
b = """x = map(None, l)[0]"""
a = """x = list(l)[0]"""
self.check(b, a)
b = """x = map(lambda x:x, l)[0]"""
a = """x = [x for x in l][0]"""
self.check(b, a)
b = """x = map(f, 'abc')[0][1]"""
a = """x = list(map(f, 'abc'))[0][1]"""
self.check(b, a)
def test_trailing_comment(self):
b = """x = map(f, 'abc') # foo"""
a = """x = list(map(f, 'abc')) # foo"""
@ -3066,11 +3096,6 @@ class Test_map(FixerTestCase):
"""
self.warns(b, a, "You should use a for loop here")
# XXX This (rare) case is not supported
## b = """x = map(f, 'abc')[0]"""
## a = """x = list(map(f, 'abc'))[0]"""
## self.check(b, a)
def test_map_nochange(self):
a = """b.join(map(f, 'abc'))"""
self.unchanged(a)
@ -3130,6 +3155,10 @@ class Test_zip(FixerTestCase):
super(Test_zip, self).check(b, a)
def test_zip_basic(self):
b = """x = zip()"""
a = """x = list(zip())"""
self.check(b, a)
b = """x = zip(a, b, c)"""
a = """x = list(zip(a, b, c))"""
self.check(b, a)
@ -3138,6 +3167,15 @@ class Test_zip(FixerTestCase):
a = """x = len(list(zip(a, b)))"""
self.check(b, a)
def test_zip_trailers(self):
b = """x = zip(a, b, c)[0]"""
a = """x = list(zip(a, b, c))[0]"""
self.check(b, a)
b = """x = zip(a, b, c)[0][1]"""
a = """x = list(zip(a, b, c))[0][1]"""
self.check(b, a)
def test_zip_nochange(self):
a = """b.join(zip(a, b))"""
self.unchanged(a)

1
Misc/ACKS
View File

@ -128,6 +128,7 @@ Andrew Bennetts
Andy Bensky
Bennett Benson
Ezra Berch
Stuart Berg
Michel Van den Bergh
Julian Berman
Brice Berna