Macro make

macro_rules! make {
    (
        $(
            $(#[doc = $doc:expr])*
            $vis:vis enum $Enum:ident[$off:expr] {
                $(
                    $(#[doc = $var_doc:expr])*
                    $Var:ident = $TOK:ident,
                )+
            }
        )*
    ) => { ... };
}

Generate an enum implementing Tag, enforcing at compile time that the discriminant values are distinct.