Rust

101:

• Scope Syntax:
  • Everything between matched {}
  • Scopes can nest {Outer Scope {Inner Scope}}
  • Pay attention to a value’s scope!

• Function Syntax:

  • fn myfunction { ... }

  • fn myfunction (arg: type, arg: type) - > resulttype { ... }

  • Type signatures are like Mad Libs

  • Function has at least name and scope

• Macro Syntax:

  • Shorthand for functions with variable number of arguments

  • macroname!(foo, bar, baz)

  • doc.rust-lang.org/beta/book/macros.html

  • You’ll see “println!”

• Punctuation Matters:

  • Expressions end with a semicolon

  • Exception: bare expression on last line of function returns result

  • Spaces separate tokens: i32 is not i 32

  • Whitespace is mostly irrelevant

• Control Flow Syntax:

  • Conditionals and loops are familiar

    • if x { ... }

    • loop { ... }

    • while x { ... }

    • for x in 1..100 { ... }

  • Match statements combine conditionals

    • https://doc.rust-lang.org/book/if.html

    • https://doc.rust-lang.org/book/loops.html

    • https://doc.rust-lang.org/book/match.html

• Function Example:

fn halve(x: i32) -> i32 {
    return x / 2;
}

fn main(){
    println!("{}", halve(4));
}

Matching on a Variable:

fn main() {
    let day = 19;
    println!("January {} 2017 is:", day);
    match day {
        15 => println!("Travel to Hobart"),
        16 | 17 => println!("Miniconf Time"),
        18...20 => println!("The Conference"),
        _ => println!("not LCA at all"),
    }
}