Rust Option

playground.rs

#[derive(Debug)]
struct Data;

//By default, variables must have a value
//Option<T> lets you explicitly bind to 'None'
fn might_be_null(input: bool) -> Option<Data> {
  if input {
    Some(Data)
  }
  else {
    None
  }
}

fn main() {
  let not_null = might_be_null(false);
  
  //You have to match on your result to see what it contains
  match not_null {
    Some(data) => println!("told you: {:?}", data),
    None => println!("It was null all along!? I'm so lucky Rust has my back!")
  }
  
  //You can also use helpers like 'is_some', 'ok_or', 'map' etc
}