Rust Results

playground.rs

fn maybe_works(i: i32) -> Result<(), String> {
  //The try! macro makes early return from errors easier. There's a '?' operator coming soon
  //Composing error types and implementing Error can suck, so libraries like error_chain help
  
  //Result has similar helpers to Option
  try!(must_not_be_negative(i));
  
  Ok(())
}

fn must_not_be_negative(i: i32) -> Result<(), &'static str> {
  if i > 0 {
    Ok(())
  }
  else {
    Err("error")
  }
}

fn main() {
  println!("{:?}", maybe_works(1));
  println!("{:?}", maybe_works(-1));
}