Licheng Fang wrote:
> On Apr 14 2003, 10:30 pm, Alex Martelli <[EMAIL PROTECTED]> wrote:
>> Sebastian Wilhelmi wrote:
>> > Hi,
>>
>> > I would like to do the following:
>>
>> > -------8<-------8<-------8<-------8<-------
>> > def test ():
>> > count = 0
>> > def inc_count ():
>> > count += 1
>> > inc_count ()
>> > inc_count ()
>> > print count
>>
>> > test ()
>> > -------8<-------8<-------8<-------8<-------
>>
>> > This doesn't work (and I even understand, why ;-)
>>
>> Specifically: a nested function cannot *RE-BIND* a variable of
>> an outer function.
>>
>
> Sorry to dig up this old thread, but I would like to know what's the
> rationale is. Why can't a nested function rebind a variable of an
> outer function?
Because the lack of variable declarations in python makes the
left-hand-side-appearance of a variable the exact distinction criteria
between inner and outer scopes. Thus it can't rebind them. What you can do
is to use mutables as container for outer variables:
def outer():
v =[1]
def increment():
a = v[0]
a += 1
v[0] = a
increment()
print v[0]
Diez
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