__del__: when to use it? What happens when you SystemExit/NameError wrt del? Method vs function calls.

[Ben Finney]

"Veek. M" <vek.m1234 at gmail.com> writes:

> 1. What are the rules for using __del__ besides: 'don't use it'.

What do you mean by “rules”?

If you want advice on using that method, I don't think a canonical
exhaustive “rules” set exists.

For example: Use ‘__del__’ to mark an object as no longer used; don't
expect that to result in the object actually going away at any
particular point in time.

> 2. What happens when I SystemExit? __del__ and gc are not invoked when
> I SystemExit and there's a circular reference - but why?

So that we can have a concrete example: Can you give a (very minimal and
simple) example demonstrating the behaviour, so we can run it too?

> 3.
> import foo
> def __del__(self, foo=foo):
>   foo.bar()

That appears to be a module-level function. It is not a method of any
class, so I am not clear on how it relates to garbage collection.

> 4. also, are method calls more efficient than function calls?

All method calls are function calls. This is because all methods are
functions.

-- 
 \     “Unix is an operating system, OS/2 is half an operating system, |
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Ben Finney