Scalable Web Development in Rust/

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Macros

Macros

Learn to use metaprogramming in Rust.

We'll cover the following...

Introduction to macros

Macros are the Rust metaprogramming feature that creates code in compile-time. Through this, we can save duplication, but we need to be careful because we could make a mess.

Macros are called using a ! in the end. We’ve been using a macro called println! to print text to the standard output.

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macro_rules! says_hi {
    () => {
        {
            println!("Hello World!");
        }
    };
}
fn main() {
    says_hi!();
}

The above code shows a simple macro to print a message. When we want to create a macro, we need to ...