effects_exception_handling.rs

mod exception_handling {
    pub trait Exception<B> {
        fn raise<A, K>(self, v: (), k: K) -> B
        where
            K: FnOnce(A) -> B;
    }

    pub struct ExceptionDiv {}
    impl Exception<()> for ExceptionDiv {
        fn raise<A, K>(self, _: (), _: K)
        where
            K: FnOnce(A),
        {
            println!("Error: Division By Zero.");
        }
    }

    pub fn div(a: usize, b: usize, exception_handler: impl Exception<()>) {
        let continuation = |x| {
            println!("Result: {x}");
        };

        if b == 0 {
            exception_handler.raise((), continuation);
        } else {
            continuation(a / b);
        }
    }
}

use exception_handling::*;

fn main() {
    div(5, 2, ExceptionDiv {});
    div(5, 0, ExceptionDiv {});
}