Macro summon::fusion

macro_rules! fusion {
    (($($arg_ty:ty),*) -> $return_ty:expr) => { ... };
}

Use this to inscribe tag type/zero-sized struct (struct A;) conversions. Useful for logic.

use summon::{Tome, fusion};
#[derive(Clone)]
struct A;
struct B;
let mut tome = Tome::new();
tome.ether(A);
tome.inscribe(fusion!((A) -> B));
tome.summon::<B>().unwrap();