Pre-RFC: Catching Functions

This is an alternative design to Ok wrapping, which I am very excited about. Similar ideas have been floated in the past. Each subheading can be separated: The throw keyword The throw keyword has the semantics: throw $expr <=> return Err(From::from($expr)) This makes ? sugar for: match expr { Ok(x) => x, Err(e) => throw e, } The throw keyword is added mainly for assisting in raising errors, replac