Custom hook example

custom_hook.rs

macro_rules! format_payload {
    ($payload:expr, $($p_type:ty),+) => {{
        $(
            if let Some(result) = $payload.downcast_ref::<$p_type>() {
                format!("{}", result)
            }
         )else+
         else {
             format!("{:?}", $payload)
         }
    }};
}

fn main() {
    std::panic::set_hook(Box::new(|info| {
        let payload = info.payload();

        let msg = format!("{}{}",
                          info.location()
                              .map(|loc| format!("{}:{} - ", loc.file(), loc.line()))
                              .unwrap_or("".to_string()),
                          format_payload!(payload, String, &'static str));

        println!("Fatal error: {}", msg);
    }));

    panic!("lolka");
}