| Rust provides Higher Order Functions (HOF), these are functions that take a | |
| closure as argument to produce a more useful function. HOFs and lazy iterators | |
| give Rust its functional flavor. | |
| {hof.play} | |
| [Option](http://doc.rust-lang.org/core/option/type.Option.html) | |
| and | |
| [Iterator](http://doc.rust-lang.org/core/iter/trait.Iterator.html) | |
| implement their fair share of HOFs. |