Asynchronous Error Handling in Swift 2.0
As Swift 1.0 did not include support for exceptions, a common error handling pattern was to use a Result enum that either took on a value on success, or an error on failure. In a way, this was superior to using exceptions, since being a instantiable type, Results could be passed around freely, enabling asynchronous code to use the same error handling mechanisim as synchronous code. Using Swift's robust support for custom operators, this also enabled Railway Oriented Programming for more functional oriented programers.
Swift 2.0 introduces throwable errors, which are similar to exceptions. However, like exceptions, thrown errors