[Manishearth]

https://github.com/bluss/ordermap is 100% safe rust and pretty fast

I believe the stdlib one could be refactored, but I'm not sure. There are a lot of optimizations in that one.

IMO "no unsafe code" is a stretch. "no unnecessary unsafe code" is what it should be.

[Animats]

That "ordermap" is nice. Could that replace std::collections::hash_map as the main supported map crate?

It imports std::collections::hash_map, which has unsafe code, but only for RandomState, which does not. If RandomState were pulled out of hash_map and moved to a crate with no unsafe code, that dependency could be removed and it would be safe crates all the way down.

IMO "no unsafe code" is a stretch. "no unnecessary unsafe code" is what it should be.

The author of the code doesn't get to determine "unnecessary". That should require extensive and hard to get justification.

[Manishearth]

> Could that replace std::collections::hash_map as the main supported map crate?

No, it is more specialized for certain kinds of loads.

> It imports std::collections::hash_map, which has unsafe code, but only for RandomState, which does not. If RandomState were pulled out of hash_map and moved to a crate with no unsafe code, that dependency could be removed and it would be safe crates all the way down.

That's a very vacuous distinction.

This is all in the same crate (std) anyway, it's just a different module.

> The author of the code doesn't get to determine "unnecessary".

The auditors (proposed in this blog post) do.

I've audited unsafe in the past to ensure our dependencies are fine, there are some pretty reasonable ways to define "unnecessary" here.

[kzrdude]

Sure, it could replace the stdlib hash map. It would regress performance for some usage and improve it for others. (And this makes it an unlikely candidate; pure improvements are a lot easier to get in.)