Macro build_register_view 

macro_rules! build_register_view {
    (
        $(#[$($reg_attrs:tt)*])*
        $reg:ident, $state:path, $state_perms:path, $priority:ident ;
        $(
            $(#[$($field_attrs:tt)*])*
            $field:ident : $perms:expr
        ),+ $(,)*
    ) => { ... };
}