# Easy doc initialization ## Description If a struct takes significant effort to initialize, when writing docs it can be quicker to wrap your example with a function the struct as an argument. ## Motivation Sometimes there is a struct with multiple or complicated parameters and several methods. Each of these methods should have examples. For example: ```rust struct Connection { name: String, stream: TcpStream, } impl Connection { /// Sends a request over the connection. /// # Example /// ```no_run /// # //This is some really borring boiler plate to get an example working. /// # let stream = TcpStream::connect("127.0.0.1:34254"); /// # let connection = Connection{ name: "Foo".to_owned(), stream: stream }; /// # let request = Request::new("ReuqestId", RequestType::Get, "dummy_payload"); /// let result = connection.send_reqest(request); /// // do stuff with result. /// ``` fn send_reqest(&self, request: Request) -> Result { //... } /// Oh no all that boiler plate needs to be repeated here !!! fn check_status(&self) -> Status { //... } } ``` ## Example Instead of typing all of this boiler plate to create an `Connection` and `Request` it is easier to just create a wrapping dummy function which takes them as arguments: ```rust struct Connection { name: String, stream: TcpStream, //... } impl Connection { /// Sends a request over the connection. /// # Example /// ``` /// # fn call_send(connection: Connection, request: Request) { /// let result = connection.send_reqest(); /// // do stuff with result. /// # } /// ``` fn send_reqest(&self, request: Request) { //... } } ``` ## Advantages This is much more concise and avoids repetitive code in examples. ## Disadvantages Because the example is in a function, the code won't actually be tested. (Though it still will checked to make sure it compiles when running a `cargo test`) So this pattern is most useful when you would need to add `no_run` anyway. ## Discussion If assertions are not required this pattern works well. If they are, an alternative can be to create a public method to create a dummy instance which is annotated with `#[doc(hidden)]` (so that users won't see it). Then this method can be called inside of Rustdocs because it is part of the crate's public API.