Python 2.x闭包(enclosure)中的变量访问&修改

http://stackoverflow.com/questions/3190706/nonlocal-keyword-in-python-2-x

---answer----

Python can read nonlocal variables in 2.x, just not change them. This is annoying, but you can work around it. Just declare a dictionary, and store your variables as elements therein

python2.x天然支持nolocal类变量访问，只要不改变他们的“值“就好了。因此用dict/tuple就可以绕过。

demo如下：

>>> def make_sequence():
...     data={'sequence':0}
...     def handler(result):
...             data['sequence']+=1
...             print '[%d] Got: %s'%(data['sequence'], str(result))
...     return handler