Rust

description: Rust Programming Language - Low level language

lang: ENG

Basics

  • std is the standard rust library.
  • Libraries brought into the scope by rust from the std library are called the prelude.
  • Statements are instructions that perform some action and do not return a value.
  • Expressions evaluate to a resultant value. They don't end with a semicolon.

Syntax

Comments

  • They are always the same:
// Rust use only the one line comment
// so you don't have to worry about various
// styles!

Main

  • This is how you start a rust program:
fn main() {
    // Program
}

Imports

  • Bring some library into the scope:
use std::io;

Constants and variables

  • Immutable variable:
let x = 5;
let x = 6;
// Forbidden: x = 6
  • Mutable variable:
let mut x = 5;
x = 6;
  • Constants:
const I_AM_A_CONSTANT: u32 = 42;

Tuples

let tuple: (i32, f32, bool, char) = (500, 6.4, true, 'a');
let (i,f,b,c) = tuple; // Deconstruction
let f = tuple.1; // Field access

Arrays

let x = [1,2,3,4,4];
let x: [i32; 5] = [1,2,3,4,4];
let x = [4; 5]; // = [4, 4, 4, 4, 4];
let first = x[0];

Functions

fn function_name(arg: i32) -> i32 {
    return arg + 2;
}

Printing

  • We can print value using println! placeholders:
let x = 1;
let y = 2;

println!("x = {x}, y = {}", y);

Pattern matching

let x = match res {
    Ok(num) => num,
    Err(_) => continue,
}

If-then-else

  • if-then-else acts like a variable and can be consume by a variable or as a return expression from a function.
if boolean_expression {
    // Case one!
} else if another_expression {
    // Another case!
} else {
    // Final case!
}

Loop

  • Infinity loop:
loop {
    // Need a break; to leave this loop.
}
  • Infinite loop with return result:
let mut counter = 0;
let result = loop {
    counter += 1;
    if counter == 10 {
        break counter * 2;
    }
};
  • Loop label:
'label: loop {
    break 'label;
}
  • While loop:
let mut number = 10;
while number != 0 {
    number -= 1;
}
  • For loop:
for element in collection {
    // Do something.
}

for number in (0..4) {
    // Do something too.
}

Cmdline

Rustc

  • To compile a code, just run:
rustc file.rs
./file

Cargo

Create a new project

cargo new <project_name>

Build a project

cargo build

Build and run a project

cargo run

Check the code is correct

cargo check

Resources

Library docs

Learning