Macro named_parameters_verb 

macro_rules! named_parameters_verb {
    ($($input:tt)*) => { ... };
}

Define a verb using a closure, where the argument names are used as the key names

let mut dsl = TestDsl::<()>::new();

dsl.add_verb(
    "test",
    named_parameters_verb!(|_harness: &mut (), name: String, pi: usize| {
        println!("{name} = {pi}");
        Ok(())
    }),
);