文件評論

Rust 提供了兩種型別的文件註釋：內部文件註釋和外部文件註釋。以下提供各自的例項。

內部文件評論

mod foo {
    //! Inner documentation comments go *inside* an item (e.g. a module or a 
    //! struct). They use the comment syntax //! and must go at the top of the
    //! enclosing item. 
    struct Bar {
        pub baz: i64
        //! This is invalid. Inner comments must go at the top of the struct,
        //! and must not be placed after fields.
    }
}

外部文件評論

/// Outer documentation comments go *outside* the item that they refer to.
/// They use the syntax /// to distinguish them from inner comments.
pub enum Test {
    Success,
    Fail(Error)
}