Documentation

Rust comes with extensive documentation. For example:

• All of the details about loops.
• Primitive types like u8.
• Standard library types like Option or BinaryHeap.

Use rustup doc --std or https://std.rs to view the documentation.

In fact, you can document your own code:

/// Determine whether the first argument is divisible by the second argument.
///
/// If the second argument is zero, the result is false.
fn is_divisible_by(lhs: u32, rhs: u32) -> bool {
    if rhs == 0 {
        return false;
    }
    lhs % rhs == 0
}

The contents are treated as Markdown. All published Rust library crates are automatically documented at docs.rs using the rustdoc tool. It is idiomatic to document all public items in an API using this pattern.

To document an item from inside the item (such as inside a module), use //! or /*! .. */, called “inner doc comments”:

//! This module contains functionality relating to divisibility of integers.

This slide should take about 5 minutes.

• Show students the generated docs for the rand crate at https://docs.rs/rand.