alt Hacker NewsSeems like a long way to walk though. Retrofitting this will take time (if it'll ever complete). Zig made it a core part of the language and library. I'll assume Rust will make it farther than C++ ever made it, but just take a look at how retrofitting custom allocators is going there.
Seems like it will be useful for use-cases like embedded where you're restricted to certain parts of the library anyway. But the battle is kind of already lost for support at the level of Zig or Odin. Even if they retrofitted support for the whole standard library, they'll never be able retrofit all crates or make people even bother adding support for all new crates.
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Rust's Allocator APIs have been around since 2016, less than a year after 1.0, they're just now stabilized.
The stdlib types that allocate have been generic (with default generic parameters) over the underlying Allocator used for a very long time. All widely-used data structure libraries where it's feasible/reasonable to use other allocators also are already generic over the Allocator.
It won't "take time to retrofit" because the language and ecosystem have already been prepared for it for 10 years. For context, async syntax was introduced a few years after that and if you just started learning the language today you wouldn't notice it wasn't there in 1.0.
> Seems like it will be useful for use-cases like embedded where you're restricted to certain parts of the library anyway. But the battle is kind of already lost for support at the level of Zig or Odin.
Odin in particular does a simply terrible job here. Take the most common need for allocations, a growable array type, in Rust Vec<T> and in Odin dynamic[T]
In Rust we only pay extra to store the allocator metadata if there is allocator metadata. If we're content using the general purpose allocator Global with global metadata it's free. In Odin we always need to pay to store an "allocator proc" function pointer and a (possibly unused) metadata pointer, so that's 2x machine word worse for Odin. We pay this even if we never allocate, and indeed even if we can't allocate, whereas of course in Rust that's free.
But then when we do need to allocate, in Rust that's a static dispatch unless our allocator specifically wants dynamic dispatch. So again for Global it's just a static dispatch. But in Odin it's always a slower dynamic dispatch.
The upside? To the extent there is one it's probably the New Jersey style, ie it was simpler to implement Odin. Which is a benefit to Ginger Bill, but not to you as an Odin programmer.