Comment by greenhouse_gas

My issue with Monads (and why I like kotlin and swift nullable types) is that it allows the compiler to infer nullability like the following code:

fun f(a1: Int?, a2: Int?): Int {

  if (a1 == null || a2 == null) {

     return 0

   } 

   //now you can do something like

   return a1+a2

}

In contrast, if it didn't, the code would look like:

fn func1(q: Option<i32>, z: Option<i32>) -> i32 {

    if let Some(q_in) = q {

        if let Some(z_in) = z {

            return q_in + z_in

        }

    }

    return 0

}

Note the deeply nested parenthesis.