Macro struct 

macro_rules! struct {
    (
        $(#[$($struct_doc:meta),*])*
        $struct_vis:vis struct $struct_identifier:ident
        $(<
            $($struct_generics:tt),*
        >)?
        $(where
            $($where_alias:ty : $($where_boundary:tt)::* $(<$($($where_boundary_generics:tt)::*),*>)?),*
        )? $(,)?
        {
            $(
                $(#[$($field_doc:meta),*])*
                $field_vis:vis $field_identifier:ident : $field_type:ty
            ),* $(,)?
        }
    ) => { ... };
}