Rust Programming Cookbook

How to do it...

You are only a few steps from creating macros:

1. Run cargo new custom-macros in Terminal (or PowerShell on Windows) and open the directory with Visual Studio Code.
2. Open src/main.rs in the editor. Let's create a new macro called one_plus_one at the top of the file:

// A simple macro without argumentsmacro_rules! one_plus_one {    () => { 1 + 1 };}

3. Let's call this simple macro inside the main function:

fn main() {    println!("1 + 1 = {}", one_plus_one!());}

4. This was a very simple macro, but macros can do so much more! How about one that lets us decide on the operation. Add a very simple macro to the top of the file:

// A simple pattern matching argumentmacro_rules! one_and_one { (plus) => { 1 + 1 }; (minus) => { 1 - 1 }; (mult) ...