[Python-Dev] Explicit Lexical Scoping (pre-PEP?)

[Ka-Ping Yee]

On Thu, 13 Jul 2006, Fredrik Lundh wrote:
> Boris Borcic wrote:
>
> >> note that most examples of this type already work, if the target type is
> >> mutable, and implement the right operations:
> >>
> >>       def counter(num):
> >>           num = mutable_int(num)
> >>           def inc():
> >>               num += 1
> >>               return num
> >>           return inc
[...]
> feel free to replace that += with an .add(1) method call; the point
> wasn't the behaviour of augmented assigment, the point was that that the
> most common use pattern involves *mutation* of the target object.

I don't think that's clear.  In:

    a = 1
    b = a
    a += 1

it doesn't seem common to me that one would expect b to become 2.
Sometimes you want mutation, sometimes you don't.  I don't think
that necessarily follows from whether you are accessing a free
variable.


-- ?!ng