python 9-4 如何实现属性可修改的函数装饰器,python3 nolocal或者在python2中列表方式

9-4 如何实现属性可修改的函数装饰器

解决方案:

python3 nolocal

为包裹函数添加一个函数，用来修改闭包中使用的自由变量.

python中，使用nonlocal访问嵌套作用域中的变量引用,或者在python2中列表方式,这样就不会在函数本地新建一个局部变量

from functools import wraps
import time
import logging
def warn(timeout):
timeout = [timeout]
def deco(func):
def wrapper(*args,**kwargs):
start = time.time()
res = func(*args,**kwargs)
used = time.time() -start
if used > timeout[0]:
msg = '"%s" : %s > %s'%(func.__name__,used,timeout[0])
logging.warn(msg)
return res
def setTimeout(k):
#nonlocal timeout
timeout[0] = k
print "timeout was given...."
wrapper.setTimeout = setTimeout
return wrapper
return deco

from random import randint

@warn(1.5)
def test():
print "in test..."
while randint(0,1):
time.sleep(0.5)

for _ in range(30):
test()

test.setTimeout(1)

print "after set to 1...."

for _ in range(30):
test()