Rust Cheatsheet

Written 2020-08-17 — Updated 2021-01-25

https://github.com/rust-unofficial/patterns has a lot of patterns
Error Handling
- anyhow is great for just merging random errors together when you don't really care otherwise and just want to get the error message out and all the various errors to have the same type. (i.e. most CLI utilities)
- thiserror is nice for structured error types where you want to add extra formatting or otherwise handle errors in a more detailed way.
  - Can wrap an anyhow inside a thiserror as well
  - ```
  #[derive(Error, Debug)]
  pub enum RequestError {
    #[error("Invalid query string: {0}")]
    QueryStringError(#[from] serde_qs::Error),
  
    #[error(transparent)]
    Other(#[from] anyhow::Error),
  }
```
Partial Moves
- Rust doesn't allow moving part of a structure out, but there are better ways than just clone.
- Use mem::replace to take items out from structures without needing to take ownership of the entire thing.
- Destructuring also helps when you want to eventually move all the items out of the structure.
Performance
- fxhash crate is good for fast hashing that doesn't need to be cryptographically secure.
- Rust Performance Book
- Enable Link-time Optimization
  - ```
  [profile.release]
  lto = true
```
Debugging
- Use the CodeLLDB extension in VS Code
- For vim, https://alpha2phi.medium.com/setting-up-neovim-for-rust-debugging-termdebug-and-vimspector-df749e1ba47c walks through the process of setting up CodeLLDB with the Vimspector plugin.
- In unit tests use cargo test -- --nocapture to show anything the tests write to stdout

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