Comment by steveklabnik

5 years ago

That is being backfilled in; Vec already implements it on nightly, IIRC.

And really, what you're talking about here is "the standard library data structures," which aren't super likely to be used in firmware anyway. It's a lot easier for ecosystem data structures to add support, after all, they already would choose to call the global allocator, so now they can do either. And it is much easier for them to cut backwards-incompatible changes, if they have to.

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steveklabnik

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yellowapple  5 years ago

> which aren't super likely to be used in firmware anyway.

Why not? Zig's std library is specifically designed to be usable for freestanding/baremetal targets (e.g. firmware), and the compiler is smart enough to only include the parts of a library (including std) that are actually used. If you do need to reimplement a part of std, you can just... reimplement that part, and import your own implementation instead of the one from std.

Unless you're talking purely about Rust?

  • steveklabnik  5 years ago

    I am talking purely about Rust, yes. Firmware tends to use libcore, and if it does happen to dynamically allocate memory, liballoc. libstd assumes you have an OS, so...

glandium  5 years ago

I mean, in terms of Rust, it sounds like Zig allows to use any allocator for anything in any crate. Not only structs in std or other crates that explicitly allow a custom allocator. In Rust, and only talking about std, you'd need to change a lot of things to allow e.g. BufWrite, etc. to use a custom allocator. And every crate that uses types that allocate stuff under the hood. But maybe I'm misunderstanding what Zig allows.