[Python-Dev] Garbage collecting closures
Phillip J. Eby
Mon, 14 Apr 2003 12:08:38 -0400
At 11:58 AM 4/14/03 -0400, Jeremy Hylton wrote:
>On Mon, 2003-04-14 at 11:52, Phillip J. Eby wrote:
> > If I understand correctly, it should also be breakable by deleting 'foo'
> > from the outer function when you're done with it. E.g.:
> > def bar(a):
> > def foo():
> > return None
> > x = a
> > foo()
> > del foo # clears the cell and breaks the cycle
>You haven't tried this, have you? ;-)
Well, I did say, "If I understand correctly". :)
What's funny is, I could've sworn I've used 'del' under similar
circumstances before. It must not have been to delete a cell, just deleting
something else in a function that defined a function. Ah well.
>SyntaxError: can not delete variable 'foo' referenced in nested scope
Interestingly, it gives me a different error in IDLE: "unsupported operand
type(s) for -: 'NoneType' and 'int'"
>Since foo() could escape bar, i.e. become reachable outside of bar(), we
>don't allow you to unbind foo.
So do this instead:
foo = None