Rust code shared from the playground

playground.rs

pub struct Convex<T: AsRef<[Point]> + ?Sized> {
    vertices: T
}

pub struct Point(f32, f32);

impl<T: AsRef<[Point]>> Convex<T> {
    pub fn new(vertices: T) -> Option<Convex<T>> {
        fn is_polygon_convex(_: &[Point]) -> bool { true }
        let is_convex = {
            let vs = vertices.as_ref();
            vs.len() >= 3 && is_polygon_convex(vs)
        };
        
        if is_convex {
            Some(Convex { vertices })
        } else {
            None
        }
    }
}

impl<T: AsRef<[Point]> + ?Sized> Convex<T> {
    fn pointsum(&self) -> Point {
        self.vertices.as_ref().iter().fold(Point(0.0, 0.0), |p1, p2|Point(p1.0 + p2.0, p1.1 + p2.1))
    }
}

fn main() {
    let points = [Point(1.0, 2.0), Point(3.0, 4.0), Point(5.0, 6.0)];
    let c = Convex::new(points).expect("A convex");
    let c: &Convex<[Point]> = &c;
    let ps = c.pointsum();
    println!("{} {}", ps.0, ps.1);
}