Rust errors

Rust has two primary methods of handling errors.

• panic!() halts/exits the program
• Result types are for handle-able errors

panic

• intended for halting application, not control flow
• have backtraces

panic!("tried to X but couldn't Y")

// convert panic to result
// (not intended for native rust code)
let result = panic::catch_unwind(|| {
    panic!("oh no!");
});

Result

The result type is an enum, whose options Ok, Err have been merged into the global scope through prelude.

Example.

fn is_one(i: isize) -> Result<String, String> {
    if i == 1 {
        Ok("success".to_string())

    } else {
        Err("not success".to_string())
    }
}

fn main() {
    let result = match is_one(2) {
        Ok(x) => format!("horay: {}", x),
        Err(x) => format!("[ERROR] {}", x),
    };
    println!("{}", result);
}