Question is how to do these in Rust. An example might be a browser DOM: each node has a parent pointer, a list of child pointers, left and right sibling pointers, maybe a CSS node pointer, etc. Inserting or deleting nodes has to repair the pointers to and from the neighboring nodes as needed.

I know this is doable since obviously Servo (Rust's initial driving application) has to do it. I hope the answer doesn't involve the word "unsafe". But I am quite unclear about how to create such a structure under Rust's rules of pointer ownership, and also how to reliably reclaim storage when nodes and trees/subtrees are deleted. Plus there will be thread safety rules that should be statically enforced if possible.

I've heard that doubly linked lists in Rust are handled by an unsafe library, yet this seems even worse. Thanks.

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[–] [email protected] 5 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Typically for this I've done some wrapper type around a vector storage for the node data (a wish.com arena, if you will). Links are just some abstraction around indices.

It's kind of annoying to write initially, but it was easier than learning unsafe stuff. To do it correctly & most efficiently though, one would likely need unsafe code.

[–] [email protected] 3 points 2 weeks ago

Typically for this I’ve done some wrapper type around a vector storage for the node data (a wish.com arena, if you will). Links are just some abstraction around indices.

Not sure what wish.com is, but yeah, you're describing a traditional Fortran approach. I would say machine pointers are a hardware primitive, and using indices like that are an abstraction. Anyway, the reply is appreciated. It at least tells me that I'm not missing something super obvious.