hof: No explanation how to create a function that takes a closure

[kornelski]

The example uses preexisting functions accepting closures, but doesn't show how to create one.

I'm struggling with this, because the compiler won't infer the closure type, and closure types were not explained (related #405).

fn callme<T>(callable: T) {
    callable(12i32);
}

fn main() {
    callme(|&:arg| -arg);
}

error: expected function, found T

[strega-nil]

fn callme<F>(callable: F)
        where F: Fn(i32) -> i32 {
    println!("{}", callable(12i32));
}

[mdinger]

The closures section now includes an example covering this case. This should be fixed.

[kornelski]

Thank you!