Traits in Rust

Shared behavior a type can implement.

trait Summary {
    fn summarize(&self) -> String;
}

struct Article {
    title: String,
}

impl Summary for Article {
    fn summarize(&self) -> String {
        format!("Read more: {}", self.title)
    }
}

fn main() {
    let a = Article { title: String::from("Typing") };
    println!("{}", a.summarize());
}

How it works

1. A trait declares method signatures.
2. impl Summary for Article provides them.
3. The method is then callable on the type.

Keywords and builtins used here

• Article
• String
• fn
• for
• impl
• let
• main
• self
• struct
• summarize
• trait

The run, in numbers

Lines

18

Characters to type

281

Tokens

83

Three-star pace

100 tpm

At the three-star pace of 100 tokens a minute, this run takes about 50 seconds.

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Step 1 of 3 in Traits, step 1 of 19 in Traits & generics.

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