Macro exit_with 

macro_rules! exit_with {
    ($exit_code:expr) => { ... };
    ($exit_code:expr, $($message:tt)*) => { ... };
}

https://stackoverflow.com/a/32289869/14452787

and some help from https://dev.to/rogertorres/first-steps-with-rust-declarative-macros-1f8m