Re^2: Action at a distance (updated)

I wouldn't go with tie (if it even works?). I'd overload = to automatically clone the object on assignment.

Another approach is to use immutable objects. Such a class wouldn't provide a method for incrementing the object; it would provide a method that returns a new object with the higher value.

Both of these approaches add the unnecessary computational and memory overhead of creating clones in situations where they aren't needed.

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Re^3: Action at a distance
by LanX (Saint) on Nov 03, 2022 at 15:05 UTC

> I'd overload = to automatically clone the object on assignment.

Sorry, that's too easy to misunderstand.

Let me be more precise:

$b = $a with = overloaded to ->clone will not do an immediate $b = $a->clone °

It's rather a kind of copy-on-write.

After the assignment the refs will still be identical : $b == $a

The ->clone ("copy" in COW) will only happen delayed just prior to changing $b or $a ("write" in COW)

https://perldoc.perl.org/overload#Copy-Constructor

$a = $b;
# ... (other code which does not modify $a or $b) ...
++$b;
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would be executed in a manner equivalent to
$a = $b; # ... $b = $b->clone(undef, ""); $b->incr(undef, "");
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But the wording is fuzzy and needs to be tested.

Anyway this could indeed fix the problem of the OP in an efficient way.

Cheers Rolf
_{(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :)

Wikisyntax for the Monastery}

°) In Math::BigInt the cloning is done with the method ->copy

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