Macro with_any_parser 

macro_rules! with_any_parser {
    ($any:expr, |$p:ident| $body:expr) => { ... };
}

Dispatches over every AnyParser variant, binding the concrete Parser<XCode> to $p and evaluating $body once per arm.

Written out by hand rather than generated inside mk_action! so the arm list stays a plain match: a variant missing here is a non-exhaustive-match compile error, which is the whole guarantee. Every arm is unconditional — see the AnyParser docs for why no cfg is needed. Add a line here when mk_langs! gains a language.