alt Hacker Newsstd may not yet provide a stable interface for custom allocators (the Allocator API appears to be available in unstable presently), but use of custom allocators is common in no-std rust environments like embedded. Reading through https://github.com/irbull/custom_allocators the Allocator API doesn't seem particularly complicated. I think it's fair to expect that it will stabilize in time.
> That's like saying Rust has GC because GC libraries/runtimes can be implemented in/for Rust.
Quite a few have already been implemented and are available as libraries exactly as you describe, today. I wouldn't phrase that as "Rust has GC" because that might imply that the GC is required. But if your application might benefit from GC, it's certainly available in the language. I might say "GC is optionally available in Rust if desired" to be more accurate.
https://news.ycombinator.com/item?id=46684673 (reply to sibling)
> I think it's fair to expect that it will stabilize in time.
The allocator work is facing a lot of obstacles, unfortunately. I prefer it to be unstable for as long as it needs, though.
> Quite a few have already been implemented and are available as libraries exactly as you describe, today. I wouldn't phrase that as "Rust has GC" because that might imply that the GC is required.
This is exactly my point. Rust does not prevent GC by any means, but Rust also does not encourage GC by any means. The same goes for custom allocators, aside from the highly-unstable Allocator API.