//fn main() {
//    println!("Hello, world!");
//}
//
//pub trait Iterator {
//    type Item;
//
//    fn next(&mut self) -> Option<Self::Item>;
//}
//
//
//#[derive(Debug, PartialEq)]
//struct Point {
//    x: i32,
//    y: i32,
//}
//
//impl Add for Point {
//    type Output = Point;
//
//    fn add(self, other: Point) -> Point {
//        Point {
//            x: self.x + other.x,
//            y: self.y + other.y,
//        }
//    }
//}

//fn main() {
//    assert_eq!(Point { x: 1, y: 0 } + Point { x: 2, y: 3 },
//               Point { x: 3, y: 3 });
//    println!("Done.");
//}

//trait Add<RHS=Self> {
//    type Output;
//
//    fn add(self, rhs: RHS) -> Self::Output;
//}

//use std::ops::Add;
//
//struct Millimeters(u32);
//struct Meters(u32);
//
//impl Add<Meters> for Millimeters {
//    type Output = Millimeters;
//
//    fn add(self, other: Meters) -> Millimeters {
//        Millimeters(self.0 + (other.0 * 1000))
//    }
//}


//trait Pilot {
//    fn fly(&self);
//}
//
//trait Wizard {
//    fn fly(&self);
//}
//
//struct Human;
//
//impl Pilot for Human {
//    fn fly(&self) {
//        println!("Because I was inverted.");
//    }
//}
//
//impl Wizard for Human {
//    fn fly(&self) {
//        println!("Fly, you fools.");
//    }
//}
//
//impl Human {
//    fn fly(&self) {
//        println!("*feels real loose like a long-neck goose*");
//    }
//}
//
//
//trait Animal {
//    fn baby_name() -> String;
//}
//
//struct Dog;
//
//impl Dog {
//    fn baby_name() -> String {
//        String::from("Spot")
//    }
//}
//
//impl Animal for Dog {
//    fn baby_name() -> String {
//        String::from("puppy")
//    }
//}


//fn main() {
//    let person = Human;
//    person.fly();
//    Pilot::fly(&person);
//    Wizard::fly(&person);
//
//
//    println!("A baby dog is called a {}", <Dog as Animal>::baby_name());
//
//
//    println!("Done.");
//}
//


//use std::fmt;
//
//trait OutlinePrint: fmt::Display {
//    fn outline_print(&self) {
//        let output = self.to_string();
//        let len = output.len();
//        println!("{}", "*".repeat(len + 4));
//        println!("*{}*", " ".repeat(len + 2));
//        println!("* {} *", output);
//        println!("*{}*", " ".repeat(len + 2));
//        println!("{}", "*".repeat(len + 4));
//    }
//}
//
//struct Point { 
//    x: i32,
//    y: i32,
//}
//
//impl OutlinePrint for Point {}
//
//impl fmt::Display for Point {
//    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
//        write!(f, "({}, {})", self.x, self.y)
//    }
//}
//
//fn main() {
//    let point = Point { x: 5, y: 6 };
//    point.outline_print();
//}

use std::fmt;

struct Wrapper(Vec<String>);

impl fmt::Display for Wrapper {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "[{}]", self.0.join(", "))
    }
}

fn main() {
    let w = Wrapper(vec![String::from("hello"), String::from("world")]);
    println!("w = {}", w);
}