Pattern Matching in Rust

Rust has a really awesome feature called Pattern Matching. Elixir also has this. In Rust, it’s used for matching complex data structures in a clean and expressive way. It looks like this:

match value {
    pattern1 => result1,
    pattern2 => result2,
    _ => fallback_result,  // The `_` is a catch-all pattern
}

Note the use of _ as the catch all.

Pattern Guards

We can also use if statements within pattern matching statements to do something called “pattern guards”. Looks like this:

let num = 7;

match num {
    x if x % 2 == 0 => println!("Even number"),
    x => println!("Odd number"),
}

Destructuring

We can also destructure the input data type, kinda similar to Javascript destructuring.

// example with a tuple
let point = (3, 7);

match point {
    (x, y) => println!("x is {} and y is {}", x, y),
}

// example with an inline struct
let p = Point { x: 5, y: 10 };

match p {
    Point { x, y } => println!("x is {} and y is {}", x, y),
}

This and pattern guards allow us to get even more granular and specific with how we conditionalize/match the data.