bind.rs

fn main() {
    bind("a", |a| {
        println!("{}", a)
    });

    bind(("a", "b"), |(a, b)| {
        println!("{} {}", a, b)
    });

    /*
       Uncomment to show the error:
       `bind` did take a 2-tuple, but the closure expects 3 arguments.

       ```text
       error[E0593]: closure is expected to take a single 2-tuple as argument, but it takes 3 distinct arguments
         --> src/main.rs:12:5
          |
       12 |     bind(("a", "b"), |a, b, c| {
          |     ^^^^             --------- takes 3 distinct arguments
          |     |
          |     expected closure that takes a single 2-tuple as argument
       ````
     */
    //bind(("a", "b"), |a, b, c| {
    //    println!("{} {} {}", a, b, c)
    //});
}

pub trait Bind<Params> {
    fn bind<F: 'static>(params: Self, func: F)
    where
        Self: Sized,
        F: FnMut(Params);
}

pub fn bind<Binder, Params, F>(params: Binder, func: F)
where
    Binder: Bind<Params>,
    F: 'static,
    F: FnMut(Params)
{
    Binder::bind(params, func)
}

impl Bind<String> for &str {
    fn bind<F: 'static>(params: Self, mut func: F)
    where
        Self: Sized,
        F: FnMut(String)
    {
        let param = params.to_uppercase();
        func(param);
    }
}

impl Bind<(String, String)> for (&str, &str) {
    fn bind<F: 'static>(params: Self, mut func: F)
    where
        Self: Sized,
        F: FnMut((String, String))
    {
        let params = (params.0.to_uppercase(), params.1.to_uppercase());
        func(params);
    }
}