Re: How to explicitly destroy an object so that all other references to it would become false?


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Re: How to explicitly destroy an object so that all other references to it would become false?

by bdimych (Monk)

on Feb 21, 2008 at 12:30 UTC ( #669259=note: print w/replies, xml )

Need Help??

in reply to How to explicitly destroy an object so that all other references to it would become false?

1)
Many thanks!

2)
>do you have an example?

package XXX;

my %already_created_objects;

sub new {
    my ($class, $X) = @_;
    if (!$already_created_objects{$X}) {
        $already_created_objects{$X} = bless {somekey => $X} $class;
    }
    $already_created_objects{$X}
}
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somewhere inside the script

...
$obj = new XXX($some_var_which_can_repeat);
...
if ($some_conditions) {
    some_superundef $obj
}
...
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Scalar::Util::weaken can do what I would like, but, as I've understood, it is required to mark as "weak" every reference to the object? Indirection layer seems more handy, may be...

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Re^2: How to explicitly destroy an object so that all other references to it would become false? (just 1)
by tye (Sage) on Feb 21, 2008 at 16:05 UTC

but, as I've understood, it is required to mark as "weak" every reference to the object?

No, the typical use would be to have only %already_created_objects contain weak references. Then normal object life-time control would take place and when an object is no longer referenced other than in %already_created_objects, that object would be destroyed and the value in %already_created_objects would transform into undef.

If there is some reason you want to destroy the object while there are still live references to it besides %already_created_objects, then you should give more information to justify that unusual requirement.

- tye

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