| % Closures |
| |
| <small>There is a new edition of the book and this is an old link.</small> |
| |
| > Anonymous functions you can save in a variable or pass as arguments to other functions. |
| |
| ```rust |
| # use std::thread; |
| # use std::time::Duration; |
| |
| let expensive_closure = |num| { |
| println!("calculating slowly..."); |
| thread::sleep(Duration::from_secs(2)); |
| num |
| }; |
| # expensive_closure(5); |
| ``` |
| |
| --- |
| |
| Here are the relevant sections in the new and old books: |
| |
| * **[in the current edition: Ch 13.01 — Closures][2]** |
| * <small>[In the first edition: Ch 3.23 — Closures][1]</small> |
| |
| |
| [1]: https://doc.rust-lang.org/1.30.0/book/first-edition/closures.html |
| [2]: ch13-01-closures.html |
