RUST 1

public:: true

• Cargo
  • We can create a project using cargo new. We can build a project using cargo build. We can build and run a project in one step using cargo run. We can build a project without producing a binary to check for errors using cargo check. Instead of saving the result of the build in the same directory as our code, Cargo stores it in the target/debug directory.
• Rust has statements and expressions, expressions return a value. If is an expression so you can bind the conditional to a variable. If a x+1 expression you add a ; it will become a statement
• Ownership Rules
  • First, let’s take a look at the ownership rules. Keep these rules in mind as we work through the examples that illustrate them:
    • Each value in Rust has an owner.
    • There can only be one owner at a time.
    • When the owner goes out of scope, the value will be dropped
• Rust by Example book // online https://practice.rs
  • Lifetime
    • There are elision rules → that’s why for a lot of functions we don’t need to annotate lifetime
    • but if we need, there are 2 rules
      • Any reference must have an annotated lifetime
        • Any reference being returned must have the same lifetime as one of the inputs or be static

      • fn pass_x<'a, 'b>(x: &'a i32, _: &'b i32) -> &'a i32 { x }
• cargo-watch: to execute cargo commands each time files change
  • cargo watch -x test
• Difference between Clone and Copy traits
  • • Copy is implicit, inexpensive, and cannot be re-implemented (memcpy).
  • • Clone is explicit, may be expensive, and may be re-implement arbitrarily.
• Difference between Rc, Box and RefCell
  • RefCell → is to remove the rule of “you can have n borrows non mutable or 1 mutable, for achieving this… inside uses unsafe code, so there is the possibility of crash in runtime
  • Box → is a pointer to some data in the heap → prevents the Copy trait
  • RC (Reference counting) → used on single thread, it allows to have multiple owners. Each time you use .clone() a counter is incremented, when all .clone() are out of scope the data can be drop.
• Resources:
  • https://fasterthanli.me/articles/a-half-hour-to-learn-rust