The Rust 

Programming Language

Safe - Concurrent - Fast

By Davis Silverman

fn main() { 
    println!("Hello, World!")
}

Who Am I?

  • Davis Silverman
  • Some PL Geek
  • Hobby Game Dev

What Is RUST?

  • Modern idioms, the best of all worlds  
    • Immutable by default
    • No null pointers
    • Zero cost abstractions
  • Strong ownership system
    • move semantics by default - affine types
    • pass by value or reference
  • Memory safe without garbage collection
    • Library-provided smart pointers!
  • Hygienic Macros 
    • Typesafe Metaprogramming!

Pop quiz: How many bits in a C `long double`?

Who Is behind Rust?

  • Mozilla Research
  • The Rust community!

Why?

  • A safe systems programming language
  • Appropriate for large scale client applications
  • Web browsers, servers, video games
  • Not just `Safe C++`, modern language design.

An Introduction


  • No implicit casting
  • Readable and precise grammar
  • Powerful pattern matching











fn fizzbuzz(num: uint) -> String {
    match (num % 3, num % 5) {
        (0, 0) => "FizzBuzz".to_string(),
        (0, _) => "Fizz".to_string(),
        (_, 0) => "Buzz".to_string(),
        (_, _) => num.to_string()
    }
}

fn main() -> () {
    for num in range(0u, 101) {
        println!("{}", fizzbuzz(num));
    }
}

Nouns and verbs

    http://is.gd/i9KfQK

struct Dog {
    name: String,
    age: uint,
}
impl Dog {
    fn new(name: String, age: uint) -> Dog {
        Dog {name:name, age:age}
    }
    fn bark(&self) -> String {
        format!("I am dog {}. I am {}", self.name, self.age)
    }
}
fn main() -> () {
    let hunter_dawg: Dog = Dog::new("Hunter".to_string(), 5);
    println!("{}", hunter_dawg.bark()) // See no ;
}

OPTION

PROBLEM                                                     SOLUTION

  • Null pointers suck!
  • Exceptions are expensive!
  • Error codes (-1) are not strongly typed!


  • Explicit error handling
  • Efficiently represented!
  • Strongly typed! 
http://is.gd/3saFGH 
enum Option<T> {
    Some(T),
    None
}
enum Result<T, E> {
    Ok(T),
    Err(E)
}

Algebraic data types

#[deriving(Show)]
enum List<T> {
    Nil,
    Cons(T, Box<List<T>>),
}

fn main() {
    let list: List<i32> = Cons(1i32, box Cons(2, box Cons(3, box Nil)));
    println!("{}", list);
}
  • Enum is awesome
  • Box<T> is a pointer!
  • let bindings
  • automatic inference of integers

 
    http://is.gd/C6uUfH

Ownership And Aliasing



// This function takes ownership of the heap allocated memory
fn destroy_box(c: Box<int>) {
    // Have to return it to be claimed again.
    println!("destroying a box that contains {}", c);
    // `c` will be destroyed in this scope, and the memory will be freed
}

fn borrow_variable<T: std::fmt::Show>(d: &T) {
    // Do not have to return the variable to let the caller reclaim it
    println!("variable, {} is borrowed!", d);
}

fn borrow_mut_variable(f: &mut f64) {
    *f = 42.0;
}
  • References
  • Mutable references
  • Library defined pointers
        http://is.gd/MVznjn

Concurrency!







  • Rust eliminates data races through its safety system
  • Either have unique ownership and mutability
  • Or shared ownership and immutability

fn main() {
    for i in range(0u,500) {
        spawn(proc() {
            println!("Hello, {}!", i);
        });
    }
} 
http://is.gd/TMCqCN

Problems



  • The compiler is your worst enemy....In a good way!
  • APIs constantly changing to_str -> to_string (this just got fixed :D )
  • Language has ergonomic issues - not a priority for pre 1.0 per se
 

Lifetime Annotations

Explicit lifetimes to keep track of references

struct Pair<'a, 'b> {
    one: &'a mut int,
    two: &'b mut int,
}
fn main() {
    let mut one = 1; //lifetime of 'o
    {
        let mut two = 2; //lifetime of 't, shorter because in block ('t < 'o)

        println!("Before: ({}, {})", one, two);

        // `Pair` gets specialized for `'a = 'o` and `'b = 't`
        let pair = Pair { one: &mut one, two: &mut two };

        *pair.one = 2;
        *pair.two = 1;

        println!("After: ({}, {})", pair.one, pair.two);
    }
}

source

http://is.gd/KOHNNA

Interesting projects!


  • Gamedev
  • Emulators
  • Web Browsers
    • Servo By Mozilla - Multithreaded Browser engine
  • HUGE AMOUNTS OF OTHER STUFF!

please read more


Amazing resources






Thank you!







Rust is great :) Questions?

Davis Silverman
sinistersnare@gmail.com

The Rust programming Language

By Davis Silverman

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The Rust programming Language

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