rust 特征 Trait ----来自圣经

rust 特征 Trait的简单练习，  这些代码来自 ————rust圣经 

pub trait Summary {
    fn summarize(&self) -> String{
        format!("liunn在测试{}","太好了")
    }
    fn summarize1(&self) -> String;
    fn summarize2(&self) -> String{
        format!("summarize2调用内部{}",self.summarize1())       
    }
}
pub struct Post {
    pub title: String, // 标题
    pub author: String, // 作者
    pub content: String, // 内容
}

impl Summary for Post {
    fn summarize(&self) -> String {
        format!("文章{}, 作者是{}", self.title, self.author)
    }
    fn summarize1(&self) -> String {
        format!("文章{}, 作者是{}", self.title, self.author)
    }
}

pub struct Weibo {
    pub username: String,
    pub content: String
}

impl Summary for Weibo {
    fn summarize(&self) -> String {
        format!("{}发表了微博{}", self.username, self.content)
    }
    fn summarize1(&self) -> String {
        format!("{}发表了微博{}", self.username, self.content)
    }
}

fn main() {
    let post = Post{title: "Rust语言简介".to_string(),author: "大佬".to_string(), content: "Rust棒极了!".to_string()};
    let weibo = Weibo{username: "大佬".to_string(),content: "好像微博没Tweet好用".to_string()};

    println!("{}",post.summarize());
    println!("{}",weibo.summarize2());

    notify(&post);
    notify2(&post);
    notify3(&post);
}

pub fn notify(item: &impl Summary) {
    println!("Breaking news! {}", item.summarize());
}

pub fn notify<T: Summary>(item: &T) {
    println!("Breaking news! {}", item.summarize());
}

pub fn notify2(item: &dyn Summary) {
    println!("Breaking news! {}", item.summarize());
}

pub fn notify3(item: &(impl Summary + Display)) {}

fn some_function<T: Display + Clone, U: Clone + Debug>(t: &T, u: &U) -> i32 {}

fn some_function<T, U>(t: &T, u: &U) -> i32
    where T: Display + Clone,
          U: Clone + Debug
{}

fn returns_summarizable(switch: bool) -> impl Summary {
    if switch {
        Post {
            title: String::from(
                "Penguins win the Stanley Cup Championship!",
            ),
            author: String::from("Iceburgh"),
            content: String::from(
                "The Pittsburgh Penguins once again are the best \
                 hockey team in the NHL.",
            ),
        }
    } else {
        Weibo {
            username: String::from("horse_ebooks"),
            content: String::from(
                "of course, as you probably already know, people",
            ),
        }
    }
}