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Date: Wed, 10 Jul 2024 19:34:23 +0200
To: internals@lists.php.net
Subject: [PHP-DEV] [low priority] WeakMaps with scalar keys
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From: rob@bottled.codes ("Rob Landers")

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Hello internals,

I know now that some of you are swamped getting ready for 8.4, so I want=
 to be clear that this will be an 8.5+ thing. I am simply sending it to =
the list in case anyone wants to discuss it, burn it with fire, give it =
a gold star, or ignore until later.

Currently, a WeakMap may only have object keys, and this logically makes=
 a lot of sense. However, there are cases where you want to reference an=
 object by a value but if the value is no longer referenced, no longer n=
eed it. A good example of this might be used in dependency injection con=
tainers, lookup tables for value objects, etc.

I'd like to propose a ReverseWeakMap where the keys must be scalar, and =
given an object as the value. Once the value is no longer referenced, th=
e key and value is removed from the ReverseWeakMap.

=E2=80=94 Rob
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<!DOCTYPE html><html><head><title></title><style type=3D"text/css">p.Mso=
Normal,p.MsoNoSpacing{margin:0}
p.MsoNormal,p.MsoNoSpacing{margin:0}</style></head><body><div>Hello inte=
rnals,<br></div><div><br></div><div>I know now that some of you are swam=
ped getting ready for 8.4, so I want to be clear that this will be an 8.=
5+ thing. I am simply sending it to the list in case anyone wants to dis=
cuss it, burn it with fire, give it a gold star, or ignore until later.<=
br></div><div><br></div><div>Currently, a WeakMap may only have object k=
eys, and this logically makes a lot of sense. However, there are cases w=
here you want to reference an object by a value but if the value is no l=
onger referenced, no longer need it. A good example of this might be use=
d in dependency injection containers, lookup tables for value objects, e=
tc.<br></div><div><br></div><div>I'd like to propose a ReverseWeakMap wh=
ere the keys must be scalar, and given an object as the value. Once the =
value is no longer referenced, the key and value is removed from the Rev=
erseWeakMap.<br></div><div><br></div><div id=3D"sig121229152">=E2=80=94 =
Rob<br></div></body></html>
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