Can I pass a function as a parameter? If not, what is a good alternative?

I tried some different syntaxes but I have not found the right one. I know I can do this:

```
fn example() {
    let fun: fn(value: i32) -> i32;
    fun = fun_test;
    fun(5i32);
}

fn fun_test(value: i32) -> i32 {
    println!("{}", value);
    value
}

```

but that's not passing the function as a parameter to another function:

```
fn fun_test(value: i32, (some_function_prototype)) -> i32 {
    println!("{}", value);
    value
}

```