Method area

Rust/notes.rs:1684–1692

(&self)

        // caller object. In this case `Self` = `Rectangle`
        #[allow(dead_code)]
        fn area(&self) -> f64 {
            // `self` gives access to the struct fields via the dot operator
            let Point { x: x1, y: y1 } = self.p1;
            let Point { x: x2, y: y2 } = self.p2;
    
            // `abs` is a `f64` method that returns the absolute value of the
            // caller
            ((x1 - x2) * (y1 - y2)).abs()
        }
    
        #[allow(dead_code)]
        fn perimeter(&self) -> f64 {