Macro s 

macro_rules! s {
    ($(
        $(#[$attr:meta])*
        pub $t:ident $i:ident { $($field:tt)* }
    )*) => { ... };
    (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => { ... };
    (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => { ... };
}

Implement Clone and Copy for a struct, as well as Debug, Eq, Hash, and PartialEq if the extra_traits feature is enabled.

Use [s_no_extra_traits] for structs where the extra_traits feature does not make sense, and for unions.