How to Print a Struct in Rust

So, you're programming in Rust, and one day you think it would be really nice to be able to display a printed version of your structure in memory.

This is one of the handier things I've learned to do while working with Rust. I use it all the time, and while I've memorized the pattern, I don't want to forget again.

So, here it is:

#[derive(Debug)]
struct User {
    name: String,
    id: i32
}

fn main() {
    let user = User { name: "Gary".to_string(), id: 1234 };
    println!("{:?}", user);
}

Compiling and running:

$ rustc print-struct.rs
$ ./print-struct
User { name: "Gary", id: 1234 }

Lets look at the pieces:

1. Add #[derive(Debug)] above the struct definition to have rust extend the debug trait.
2. Use {:?} inside your println! format string instead of the usual {}.

That's it! It is really simple, but it makes development sooo much easier.