Macro one_adapt 

macro_rules! one_adapt {
    ($adapt:ident, $alias:ident, $init:ident,
        $vis:vis fn $n:ident($id:ident: &$k:ty, $entity:ident: &$entity_ty:ty $(,)?) -> Option<$v:ty> {
        $($t:tt)*
    }) => { ... };
}