“Programmers are taught early to spend a great deal of time considering ‘errors’, and how to ‘handle’ them. But one of the most important programming lessons I’ve learned over the past several years is to dismiss the idea that errors are special. At the bottom, the computer is a computer. It’s a data transformation machine. An error case is simply a case. Data encoding an error is simply another form of data. Irrespective of how many language features and type variants one decides to layer on top of the computer, nothing changes this fact.”