Object Soup is Made of Indexes (jacko.io)
from fettuccinecode@programming.dev to rust@programming.dev on 24 Oct 2023 11:34
https://programming.dev/post/4850038

#rust

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beejjorgensen@lemmy.sdf.org on 24 Oct 2023 14:56 next collapse

I like this approach for Rust in general when it comes to graphs. But it suffers from many of the same kinds of issues we get with pointers, e.g. dangling pointers, use after free, and so on. Tradeoffs!

Anders429@programming.dev on 24 Oct 2023 15:09 next collapse

If you want to go one step further, a lot of game development uses a generational index, where the index is both a value and a generation, allowing you to know whether the index you currently have stored references an object that has already been destroyed and replaced by another object. Basically every ECS framework I’ve ever seen uses this pattern.

huntrss@feddit.de on 24 Oct 2023 18:28 collapse

Interesting. Can you provide a good link regarding generational index?

Anders429@programming.dev on 24 Oct 2023 21:29 collapse

I was originally introduced to the idea by this RustConf 2018 keynote: kyren.github.io/2018/09/14/rustconf-talk.html. It’s rather dense though.

I did find this random article that outlines just the concept of generational indices pretty concisely: …medium.com/generational-indices-guide-8e3c5f7fd5…

huntrss@feddit.de on 25 Oct 2023 08:55 next collapse

Thanks

oconnor663@programming.dev on 02 Nov 2023 15:23 collapse

That same keynote is linked in the last paragraph! :) The slotmap crate is also one option for generational indexes.

Anders429@programming.dev on 02 Nov 2023 20:51 collapse

Ah, you’re right! Somehow I missed that, good catch.

EthicalAI@beehaw.org on 27 Oct 2023 17:10 collapse

This is exactly right and very educational