Create your own lib

How to implement extra feature to lib.

• lib hi.rs

  #![allow(unused)]
  fn main() {
  // 👇 exclamation ! mean apply to whole file.
  #![cfg(feature = "hi")]
  pub fn hi(){
    println!(":#?", base64::encode("hi"));
  }
  }

• lib Cargo.toml

  [package]
  name = "foo"
  
  [dependencies]
  # optional true = include only when need 👇
  base64 =  { version = "0.13", optional = true }
  
  [features]
  hi = ["dep:base64"] # 👈 related crate.
  

How to use extra feature from lib.

• app Cargo.toml

  [package]
  name = "bar"
  
  [dependencies]
  # To include feature named "hi" 👇
  foo = { version = "1", features = ["hi"] }
  

How to use your lib from path

[dependencies]
pyth-sdk-solana = { path = "../pyth-sdk-solana" }

How to use your lib from github

[dependencies]
pyth-sdk-solana = { git = "https://github.com/pyth-network/pyth-sdk-rs", rev = "75e2742" }

What common traits we should derive?

• Debug
• Send for Mutex
• Sync for Arc
• Clone
• Default
• PartialEq, PartialOrd, Hash, Eq, and Ord for comparison.
• Serialize, Deserialize

💡 You can read more about this at at Rust for Rustaceans

Which function restrictions shall we use?

#![allow(unused)]
fn main() {
// Take owned String, return owned String.
fn hello(foo: String) -> String

// Take ref to str, return Copy on Write.
fn hello(foo: &str) -> Cow<'_, str>

// Take impl, return impl.
fn hello(foo: impl AsRef<Str>) -> impl AsRef<str>
}

💡 You can read more about Cow here 👉 6 things you can do with the Cow 🐄 in Rust 🦀