strange behaivor of nested function

[1989lzhh]

here is code

def make():
def jit(sig):
def wrap(function):
sig=sig[0] # unbound local error, if change to sig='' would be just fine
return function
return wrap
return jit
jit=make()
@jit('')
def f():
pass

It is strange that the interpreter complain about unbound local error.
please give me some suggestion, thanks!
Ps: I am using python 2.7
Liu Zhenhai




·¢×ÔÎÒµÄ iPhone

 

[Steven D'Aprano]

here is code

def make():
def jit(sig):
def wrap(function):
sig=sig[0] # unbound local error

You are saying:

"sig is a local variable. Assign sig to the value of sig[0]."

But what is sig? You've said it is a local variable, and at this point it
doesn't have a value yet.

Lua allows you to do this:

sig = sig[0]

will look up a global sig and assign it to the local sig first, but that
can be confusing and Python doesn't do that.