generic-function-caller-example.rs

/// compile time monomorphization
/// no runtime overhead
/// no reflection
/// no dynamic dispatch

trait Handler<T> {
    fn call(self);
}

impl<F> Handler<()> for F
where
    F: FnOnce(),
{
    fn call(self) {
        self()
    }
}

impl<F> Handler<(String,)> for F
where
    F: FnOnce(String),
{
    fn call(self) {
        self("val".to_string());
    }
}

fn caller<H, T>(c: H)
where
    H: Handler<T>,
{
    c.call();
}

fn test_1() {
    println!("test_1 called");
}

fn test_2(val: String) {
    println!("test_2: {}", val);
}

fn main() {
    caller(test_1);
    caller(test_2);
}