rust-lang / rust-lang/hashbrown

Improve Readme comparison std and FNV

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Dominant language
Rust
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Description

From the readme:

Since Rust 1.36, this is now the HashMap implementation for the Rust standard library. However you may still want to use this crate instead since it works in environments without std, such as embedded systems and kernels.

This paragraph implies that std is the same as hashbrown, but this omits that fact that std still uses SipHash and hashbrown uses AHash. Is this not a significant difference? (I'm asking since I don't fully understand these terms.)

Also, I can't find any guidance on choosing between hashbrown and FNV. Can we add this as well? Is FNV still generally the best choice when working with small keys? FNV is mentioned in the std docs so it seems warranted that this guidance should be available.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the README section quoted in the issue and review how it compares std with hashbrown. Research the stated SipHash, AHash, and FNV differences, including the question of small keys, then update the README with accurate guidance for choosing between them; done means the comparison and recommendation are clear.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
documentation
Issue type
Documentation
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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