Also, check out https://docs.python.org/3/library/weakref.html
<https://docs.python.org/3/library/weakref.html>
Maybe it will not provide exactly what you indicated, but might get some ideas
how to do things differently.
—
Now is better than never. Although never is often better than *right* now. ==
Deferred Evaluation
—
Dg
> On 9 Sep 2023, at 09:02, Jeff Allen <ja...@farowl.co.uk> wrote:
>
> On 06/09/2023 03:47, Daniel Walker wrote:
>> Perhaps this is a solution in search of a problem but I recently encountered
>> this situation in one of my projects.
>>
>> I have an object, foo, which, due to the references it contains, I'd rather
>> not keep around longer than necessary.
>>
>> I use foo to instantiate another object:
>>
>> bar = Bar(foo)
>>
>> bar is free to manipulate foo however it wants and even del it if necessary.
>> However, since the foo name is still around, those resources won't get
>> cleaned up even if bar is done with them. The simple solution is
>>
> It's a neat idea but there are other ways that may be better.
>
> I assume foo is a "specification", that is, an object you configure through a
> number of optional calls or attribute assignments, then pass to Bar() as a
> design alternative to Bar() having a complicated set of arguments. A pattern
> often used is the fluent API:
>
> bar = Bar(Foo().a().b(42).c('penguin'))
>
> Now only Bar has a reference to the Foo you made.
>
> But foo is not necessarily destroyed immediately the last reference to it is
> dropped, even with del or when nameless in the fluent API. If you wanted to
> be certain, you could make Foo a context manager to use like this:
>
> with Foo() as foo:
> foo.a()
> foo.b(42)
> foo.c('penguin')
> bar = Bar(foo)
> bar.do_stuff()
> (Think I got that right. Not tried it.) Now Foo.__exit__ can be made to
> properly tear down the resources in a foo.
>
> --
>
> Jeff Allen
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