Constructors

Rust does not provide constructors, but a common idiom is to create a new() static method, also called an associated function:

impl Point {
    fn new(x: i32, y: i32) -> Self {
        Self { x: x, y: y }
    }
}

The difference with a normal method is that it does not take &self (or one of its variations) as a parameter.

Self is the type of the self value; we could have used Point instead of Self.

When the field name is the same as the value assigned, it is possible to omit the value, as a shorthand:

fn new(x: i32, y: i32) -> Self {
    Self { x, y }
}

When we create an instance of Point with the call to its constructor (let point = Point::new();), this will allocate the value on the stack.

We can provide multiple constructors:

impl Point {
    fn origin() -> Self {
        Point { x: 0, y: 0 }
    }
}