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Unfortunately, Rust is not a good choice for this kind of tricks. This is where Zig shines. In Rust, you can’t even use proper arenas, which can help a ton with

by f311a 20d ago

Unfortunately, Rust is not a good choice for this kind of tricks. This is where Zig shines. In Rust, you can’t even use proper arenas, which can help a ton with allocations. Cloudflare started to pick Zig recently, for projects, that have memory constraints.

afdbcreid 20d ago
> In Rust, you can’t even use proper arenas You definitely can and this is done a lot. What you might mean is that you can't use standard library's collections with them (this is getting stabilized soon!) and have to use third-party, but that is a different thing than "can't use arenas". > Rust is not a good choice for this kind of tricks. Rust can do those tricks, but it's true that it is hard than in C or Zig. That said there are often crates to help.
- f311a 20d ago
  Stabilized soon, really? They did not stabilize it after 10 years and were thinking about different approach. I thought it’s dead.
  - kibwen 20d ago
    Yes, really. The design has been decided upon ( https://hackmd.io/nNHdKkp1TTK7jat0I-ABqA https://hackmd.io/nNHdKkp1TTK7jat0I-ABqA ) and the implementation has been updated to match ( https://github.com/rust-lang/rust/pull/157428 https://github.com/rust-lang/rust/pull/157428 ). The stabilization PR is just waiting on final approval by the relevant team members, with no remaining concerns currently listed: https://github.com/rust-lang/rust/pull/156882#issuecomment-5350668934 https://github.com/rust-lang/rust/pull/156882#issuecomment-5...
chlorion 20d ago
I'd like to know why I can't use arenas in rust? Especially considering that I have used them before in rust.
- f311a 20d ago
  You can’t allocate collections without nightly or without reimplementing them in the library. Every implementation uses it’s own set of trade offs to provide safety in unsafe implementation.
kibwen 20d ago
Rust supports arenas just fine ( https://crates.io/crates/bumpalo https://crates.io/crates/bumpalo ), and if you mean the support for using custom allocators in the standard library collections, that's as stable as Zig is.
- f311a 20d ago
  There are more than 10 crates for arenas with different tradeoffs, I'm well aware of them. They are still very limited compared to C/Zig.

by f311a 20d ago

afdbcreid 20d ago

> In Rust, you can’t even use proper arenas You definitely can and this is done a lot. What you might mean is that you can't use standard library's collections with them (this is getting stabilized soon!) and have to use third-party, but that is a different thing than "can't use arenas". > Rust is not a good choice for this kind of tricks. Rust can do those tricks, but it's true that it is hard than in C or Zig. That said there are often crates to help.

f311a 20d ago
Stabilized soon, really? They did not stabilize it after 10 years and were thinking about different approach. I thought it’s dead.
- kibwen 20d ago
  Yes, really. The design has been decided upon ( https://hackmd.io/nNHdKkp1TTK7jat0I-ABqA https://hackmd.io/nNHdKkp1TTK7jat0I-ABqA ) and the implementation has been updated to match ( https://github.com/rust-lang/rust/pull/157428 https://github.com/rust-lang/rust/pull/157428 ). The stabilization PR is just waiting on final approval by the relevant team members, with no remaining concerns currently listed: https://github.com/rust-lang/rust/pull/156882#issuecomment-5350668934 https://github.com/rust-lang/rust/pull/156882#issuecomment-5...

chlorion 20d ago

I'd like to know why I can't use arenas in rust? Especially considering that I have used them before in rust.

f311a 20d ago
You can’t allocate collections without nightly or without reimplementing them in the library. Every implementation uses it’s own set of trade offs to provide safety in unsafe implementation.

kibwen 20d ago

Rust supports arenas just fine ( https://crates.io/crates/bumpalo https://crates.io/crates/bumpalo ), and if you mean the support for using custom allocators in the standard library collections, that's as stable as Zig is.

f311a 20d ago
There are more than 10 crates for arenas with different tradeoffs, I'm well aware of them. They are still very limited compared to C/Zig.